The purpose of this series is to rethink how HID-BPF is invoked. Currently it implies a jmp table, a prog fd bpf_map, a preloaded tracing bpf program and a lot of manual work for handling the bpf program lifetime and addition/removal.
OTOH, bpf_struct_ops take care of most of the bpf handling leaving us with a simple list of ops pointers, and we can directly call the struct_ops program from the kernel as a regular function.
The net gain right now is in term of code simplicity and lines of code removal (though is an API breakage), but udev-hid-bpf is able to handle such breakages.
In the near future, we will be able to extend the HID-BPF struct_ops with entrypoints for hid_hw_raw_request() and hid_hw_output_report(), allowing for covering all of the initial use cases: - firewalling a HID device - fixing all of the HID device interactions (not just device events as it is right now).
The matching user-space loader (udev-hid-bpf) MR is at https://gitlab.freedesktop.org/libevdev/udev-hid-bpf/-/merge_requests/86
I'll put it out of draft once this is merged.
Cheers, Benjamin
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- Benjamin Tissoires (13): HID: rename struct hid_bpf_ops into hid_ops HID: bpf: add hid_get/put_device() helpers HID: bpf: implement HID-BPF through bpf_struct_ops selftests/hid: convert the hid_bpf selftests with struct_ops HID: samples: convert the 2 HID-BPF samples into struct_ops HID: bpf: add defines for HID-BPF SEC in in-tree bpf fixes HID: bpf: convert in-tree fixes into struct_ops HID: bpf: remove tracing HID-BPF capability selftests/hid: add subprog call test Documentation: HID: amend HID-BPF for struct_ops Documentation: HID: add a small blurb on udev-hid-bpf HID: bpf: Artist24: remove unused variable HID: bpf: error on warnings when compiling bpf objects
Documentation/hid/hid-bpf.rst | 162 +++--- drivers/hid/bpf/Makefile | 2 +- drivers/hid/bpf/entrypoints/Makefile | 93 ---- drivers/hid/bpf/entrypoints/README | 4 - drivers/hid/bpf/entrypoints/entrypoints.bpf.c | 25 - drivers/hid/bpf/entrypoints/entrypoints.lskel.h | 248 --------- drivers/hid/bpf/hid_bpf_dispatch.c | 266 +++------- drivers/hid/bpf/hid_bpf_dispatch.h | 12 +- drivers/hid/bpf/hid_bpf_jmp_table.c | 565 --------------------- drivers/hid/bpf/hid_bpf_struct_ops.c | 246 +++++++++ drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c | 9 +- drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c | 6 +- drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c | 9 +- .../hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c | 6 +- drivers/hid/bpf/progs/Makefile | 2 +- .../hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c | 6 +- drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c | 6 +- drivers/hid/bpf/progs/XPPen__Artist24.bpf.c | 10 +- drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c | 24 +- drivers/hid/bpf/progs/hid_bpf.h | 5 + drivers/hid/hid-core.c | 6 +- include/linux/hid_bpf.h | 109 ++-- samples/hid/Makefile | 5 +- samples/hid/hid_bpf_attach.bpf.c | 18 - samples/hid/hid_bpf_attach.h | 14 - samples/hid/hid_mouse.bpf.c | 26 +- samples/hid/hid_mouse.c | 39 +- samples/hid/hid_surface_dial.bpf.c | 10 +- samples/hid/hid_surface_dial.c | 53 +- tools/testing/selftests/hid/hid_bpf.c | 100 +++- tools/testing/selftests/hid/progs/hid.c | 100 +++- 31 files changed, 744 insertions(+), 1442 deletions(-) --- base-commit: 70ec81c2e2b4005465ad0d042e90b36087c36104 change-id: 20240513-hid_bpf_struct_ops-e3212a224555
Best regards,
Those operations are the ones from HID, not HID-BPF, and I'd like to reuse hid_bpf_ops as the user facing struct_ops API.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/hid_bpf_dispatch.c | 22 +++++++++++----------- drivers/hid/hid-core.c | 6 +++--- include/linux/hid_bpf.h | 4 ++-- 3 files changed, 16 insertions(+), 16 deletions(-)
diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 10289f44d0cc..55c9f82fdef0 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -21,8 +21,8 @@ #include "hid_bpf_dispatch.h" #include "entrypoints/entrypoints.lskel.h"
-struct hid_bpf_ops *hid_bpf_ops; -EXPORT_SYMBOL(hid_bpf_ops); +struct hid_ops *hid_ops; +EXPORT_SYMBOL(hid_ops);
/** * hid_bpf_device_event - Called whenever an event is coming in from the device @@ -284,13 +284,13 @@ hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags) struct device *dev; int err, fd;
- if (!hid_bpf_ops) + if (!hid_ops) return -EINVAL;
if ((flags & ~HID_BPF_FLAG_MASK)) return -EINVAL;
- dev = bus_find_device(hid_bpf_ops->bus_type, NULL, &hid_id, device_match_id); + dev = bus_find_device(hid_ops->bus_type, NULL, &hid_id, device_match_id); if (!dev) return -EINVAL;
@@ -335,10 +335,10 @@ hid_bpf_allocate_context(unsigned int hid_id) struct hid_bpf_ctx_kern *ctx_kern = NULL; struct device *dev;
- if (!hid_bpf_ops) + if (!hid_ops) return NULL;
- dev = bus_find_device(hid_bpf_ops->bus_type, NULL, &hid_id, device_match_id); + dev = bus_find_device(hid_ops->bus_type, NULL, &hid_id, device_match_id); if (!dev) return NULL;
@@ -386,7 +386,7 @@ __hid_bpf_hw_check_params(struct hid_bpf_ctx *ctx, __u8 *buf, size_t *buf__sz, u32 report_len;
/* check arguments */ - if (!ctx || !hid_bpf_ops || !buf) + if (!ctx || !hid_ops || !buf) return -EINVAL;
switch (rtype) { @@ -404,7 +404,7 @@ __hid_bpf_hw_check_params(struct hid_bpf_ctx *ctx, __u8 *buf, size_t *buf__sz, hdev = (struct hid_device *)ctx->hid; /* discard const */
report_enum = hdev->report_enum + rtype; - report = hid_bpf_ops->hid_get_report(report_enum, buf); + report = hid_ops->hid_get_report(report_enum, buf); if (!report) return -EINVAL;
@@ -459,7 +459,7 @@ hid_bpf_hw_request(struct hid_bpf_ctx *ctx, __u8 *buf, size_t buf__sz, if (!dma_data) return -ENOMEM;
- ret = hid_bpf_ops->hid_hw_raw_request(hdev, + ret = hid_ops->hid_hw_raw_request(hdev, dma_data[0], dma_data, size, @@ -501,7 +501,7 @@ hid_bpf_hw_output_report(struct hid_bpf_ctx *ctx, __u8 *buf, size_t buf__sz) if (!dma_data) return -ENOMEM;
- ret = hid_bpf_ops->hid_hw_output_report(hdev, + ret = hid_ops->hid_hw_output_report(hdev, dma_data, size);
@@ -534,7 +534,7 @@ hid_bpf_input_report(struct hid_bpf_ctx *ctx, enum hid_report_type type, u8 *buf
hdev = (struct hid_device *)ctx->hid; /* discard const */
- return hid_bpf_ops->hid_input_report(hdev, type, buf, size, 0); + return hid_ops->hid_input_report(hdev, type, buf, size, 0); } __bpf_kfunc_end_defs();
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index b1fa0378e8f4..14bbac432de5 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -2971,7 +2971,7 @@ int hid_check_keys_pressed(struct hid_device *hid) EXPORT_SYMBOL_GPL(hid_check_keys_pressed);
#ifdef CONFIG_HID_BPF -static struct hid_bpf_ops hid_ops = { +static struct hid_ops __hid_ops = { .hid_get_report = hid_get_report, .hid_hw_raw_request = hid_hw_raw_request, .hid_hw_output_report = hid_hw_output_report, @@ -2992,7 +2992,7 @@ static int __init hid_init(void) }
#ifdef CONFIG_HID_BPF - hid_bpf_ops = &hid_ops; + hid_ops = &__hid_ops; #endif
ret = hidraw_init(); @@ -3011,7 +3011,7 @@ static int __init hid_init(void) static void __exit hid_exit(void) { #ifdef CONFIG_HID_BPF - hid_bpf_ops = NULL; + hid_ops = NULL; #endif hid_debug_exit(); hidraw_exit(); diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index eec2592dec12..a66103618e6e 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -97,7 +97,7 @@ enum hid_bpf_prog_type {
struct hid_report_enum;
-struct hid_bpf_ops { +struct hid_ops { struct hid_report *(*hid_get_report)(struct hid_report_enum *report_enum, const u8 *data); int (*hid_hw_raw_request)(struct hid_device *hdev, unsigned char reportnum, __u8 *buf, @@ -110,7 +110,7 @@ struct hid_bpf_ops { const struct bus_type *bus_type; };
-extern struct hid_bpf_ops *hid_bpf_ops; +extern struct hid_ops *hid_ops;
struct hid_bpf_prog_list { u16 prog_idx[HID_BPF_MAX_PROGS_PER_DEV];
no code change, but this way we reduce code duplication and we can export it later.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/hid_bpf_dispatch.c | 47 ++++++++++++++++++++++---------------- 1 file changed, 27 insertions(+), 20 deletions(-)
diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 55c9f82fdef0..c8bb79ce2354 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -150,6 +150,25 @@ static int device_match_id(struct device *dev, const void *id) return hdev->id == *(int *)id; }
+static struct hid_device *hid_get_device(unsigned int hid_id) +{ + struct device *dev; + + if (!hid_ops) + return ERR_PTR(-EINVAL); + + dev = bus_find_device(hid_ops->bus_type, NULL, &hid_id, device_match_id); + if (!dev) + return ERR_PTR(-EINVAL); + + return to_hid_device(dev); +} + +static void hid_put_device(struct hid_device *hid) +{ + put_device(&hid->dev); +} + static int __hid_bpf_allocate_data(struct hid_device *hdev, u8 **data, u32 *size) { u8 *alloc_data; @@ -281,20 +300,14 @@ hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags) { struct hid_device *hdev; struct bpf_prog *prog; - struct device *dev; int err, fd;
- if (!hid_ops) - return -EINVAL; - if ((flags & ~HID_BPF_FLAG_MASK)) return -EINVAL;
- dev = bus_find_device(hid_ops->bus_type, NULL, &hid_id, device_match_id); - if (!dev) - return -EINVAL; - - hdev = to_hid_device(dev); + hdev = hid_get_device(hid_id); + if (IS_ERR(hdev)) + return PTR_ERR(hdev);
/* * take a ref on the prog itself, it will be released @@ -317,7 +330,7 @@ hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags) out_prog_put: bpf_prog_put(prog); out_dev_put: - put_device(dev); + hid_put_device(hdev); return err; }
@@ -333,20 +346,14 @@ hid_bpf_allocate_context(unsigned int hid_id) { struct hid_device *hdev; struct hid_bpf_ctx_kern *ctx_kern = NULL; - struct device *dev; - - if (!hid_ops) - return NULL;
- dev = bus_find_device(hid_ops->bus_type, NULL, &hid_id, device_match_id); - if (!dev) + hdev = hid_get_device(hid_id); + if (IS_ERR(hdev)) return NULL;
- hdev = to_hid_device(dev); - ctx_kern = kzalloc(sizeof(*ctx_kern), GFP_KERNEL); if (!ctx_kern) { - put_device(dev); + hid_put_device(hdev); return NULL; }
@@ -373,7 +380,7 @@ hid_bpf_release_context(struct hid_bpf_ctx *ctx) kfree(ctx_kern);
/* get_device() is called by bus_find_device() */ - put_device(&hid->dev); + hid_put_device(hid); }
static int
We do this implementation in several steps to not have the CI failing: - first (this patch), we add struct_ops while keeping the existing infra available - then we change the selftests, the examples and the existing in-tree HID-BPF programs - then we remove the existing trace points making old HID-BPF obsolete
There are a few advantages of struct_ops over tracing: - compatibility with sleepable programs (for hid_hw_raw_request() in a later patch) - a lot simpler in the kernel: it's a simple rcu protected list - we can add more parameters to the function called without much trouble - the "attach" is now generic through BPF-core: the caller just needs to set hid_id and flags before calling __load(). - all the BPF tough part is not handled in BPF-core through generic processing - hid_bpf_ctx is now only writable where it needs be
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/Makefile | 2 +- drivers/hid/bpf/hid_bpf_dispatch.c | 52 +++++++- drivers/hid/bpf/hid_bpf_dispatch.h | 4 + drivers/hid/bpf/hid_bpf_jmp_table.c | 3 + drivers/hid/bpf/hid_bpf_struct_ops.c | 246 +++++++++++++++++++++++++++++++++++ include/linux/hid_bpf.h | 64 ++++++++- 6 files changed, 362 insertions(+), 9 deletions(-)
diff --git a/drivers/hid/bpf/Makefile b/drivers/hid/bpf/Makefile index cf55120cf7d6..1cb3f31e9335 100644 --- a/drivers/hid/bpf/Makefile +++ b/drivers/hid/bpf/Makefile @@ -8,4 +8,4 @@ LIBBPF_INCLUDE = $(srctree)/tools/lib obj-$(CONFIG_HID_BPF) += hid_bpf.o CFLAGS_hid_bpf_dispatch.o += -I$(LIBBPF_INCLUDE) CFLAGS_hid_bpf_jmp_table.o += -I$(LIBBPF_INCLUDE) -hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_jmp_table.o +hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_jmp_table.o hid_bpf_struct_ops.o diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index c8bb79ce2354..7216c3c7713d 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -58,6 +58,7 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type }, .data = hdev->bpf.device_data, }; + struct hid_bpf_ops *e; int ret;
if (type >= HID_REPORT_TYPES) @@ -70,9 +71,25 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type memset(ctx_kern.data, 0, hdev->bpf.allocated_data); memcpy(ctx_kern.data, data, *size);
+ rcu_read_lock(); + list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) { + if (e->hid_device_event) { + ret = e->hid_device_event(&ctx_kern.ctx, type); + if (ret < 0) { + rcu_read_unlock(); + return ERR_PTR(ret); + } + + if (ret) + ctx_kern.ctx.retval = ret; + } + } + rcu_read_unlock(); + ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_DEVICE_EVENT, &ctx_kern); if (ret < 0) return ERR_PTR(ret); + ret = ctx_kern.ctx.retval;
if (ret) { if (ret > ctx_kern.ctx.allocated_size) @@ -122,7 +139,10 @@ u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *s
memcpy(ctx_kern.data, rdesc, min_t(unsigned int, *size, HID_MAX_DESCRIPTOR_SIZE));
- ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern); + if (hdev->bpf.rdesc_ops) + ret = hdev->bpf.rdesc_ops->hid_rdesc_fixup(&ctx_kern.ctx); + else + ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern); if (ret < 0) goto ignore_bpf;
@@ -150,7 +170,7 @@ static int device_match_id(struct device *dev, const void *id) return hdev->id == *(int *)id; }
-static struct hid_device *hid_get_device(unsigned int hid_id) +struct hid_device *hid_get_device(unsigned int hid_id) { struct device *dev;
@@ -164,7 +184,7 @@ static struct hid_device *hid_get_device(unsigned int hid_id) return to_hid_device(dev); }
-static void hid_put_device(struct hid_device *hid) +void hid_put_device(struct hid_device *hid) { put_device(&hid->dev); } @@ -205,7 +225,7 @@ static int __hid_bpf_allocate_data(struct hid_device *hdev, u8 **data, u32 *size return 0; }
-static int hid_bpf_allocate_event_data(struct hid_device *hdev) +int hid_bpf_allocate_event_data(struct hid_device *hdev) { /* hdev->bpf.device_data is already allocated, abort */ if (hdev->bpf.device_data) @@ -592,14 +612,22 @@ static const struct btf_kfunc_id_set hid_bpf_syscall_kfunc_set = {
int hid_bpf_connect_device(struct hid_device *hdev) { - struct hid_bpf_prog_list *prog_list; + bool need_to_allocate = false; + struct hid_bpf_ops *e;
rcu_read_lock(); - prog_list = rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT]); + list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) { + if (e->hid_device_event) { + need_to_allocate = true; + break; + } + } + if (rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT])) + need_to_allocate = true; rcu_read_unlock();
/* only allocate BPF data if there are programs attached */ - if (!prog_list) + if (!need_to_allocate) return 0;
return hid_bpf_allocate_event_data(hdev); @@ -623,12 +651,15 @@ void hid_bpf_destroy_device(struct hid_device *hdev) hdev->bpf.destroyed = true;
__hid_bpf_destroy_device(hdev); + __hid_bpf_ops_destroy_device(hdev); } EXPORT_SYMBOL_GPL(hid_bpf_destroy_device);
void hid_bpf_device_init(struct hid_device *hdev) { spin_lock_init(&hdev->bpf.progs_lock); + INIT_LIST_HEAD(&hdev->bpf.prog_list); + mutex_init(&hdev->bpf.prog_list_lock); } EXPORT_SYMBOL_GPL(hid_bpf_device_init);
@@ -662,6 +693,13 @@ static int __init hid_bpf_init(void) return 0; }
+ /* register struct_ops kfuncs after we are sure we can load our preloaded bpf program */ + err = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &hid_bpf_kfunc_set); + if (err) { + pr_warn("error while setting HID BPF tracing kfuncs: %d", err); + return 0; + } + /* register syscalls after we are sure we can load our preloaded bpf program */ err = register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &hid_bpf_syscall_kfunc_set); if (err) { diff --git a/drivers/hid/bpf/hid_bpf_dispatch.h b/drivers/hid/bpf/hid_bpf_dispatch.h index fbe0639d09f2..e52c43d81650 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.h +++ b/drivers/hid/bpf/hid_bpf_dispatch.h @@ -10,12 +10,16 @@ struct hid_bpf_ctx_kern { u8 *data; };
+struct hid_device *hid_get_device(unsigned int hid_id); +void hid_put_device(struct hid_device *hid); +int hid_bpf_allocate_event_data(struct hid_device *hdev); int hid_bpf_preload_skel(void); void hid_bpf_free_links_and_skel(void); int hid_bpf_get_prog_attach_type(struct bpf_prog *prog); int __hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_type, int prog_fd, struct bpf_prog *prog, __u32 flags); void __hid_bpf_destroy_device(struct hid_device *hdev); +void __hid_bpf_ops_destroy_device(struct hid_device *hdev); int hid_bpf_prog_run(struct hid_device *hdev, enum hid_bpf_prog_type type, struct hid_bpf_ctx_kern *ctx_kern); int hid_bpf_reconnect(struct hid_device *hdev); diff --git a/drivers/hid/bpf/hid_bpf_jmp_table.c b/drivers/hid/bpf/hid_bpf_jmp_table.c index aa8e1c79cdf5..8a54ba447718 100644 --- a/drivers/hid/bpf/hid_bpf_jmp_table.c +++ b/drivers/hid/bpf/hid_bpf_jmp_table.c @@ -81,6 +81,9 @@ static int hid_bpf_program_count(struct hid_device *hdev, if (type >= HID_BPF_PROG_TYPE_MAX) return -EINVAL;
+ if (type == HID_BPF_PROG_TYPE_RDESC_FIXUP && hdev->bpf.rdesc_ops) + n += 1; + FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { struct hid_bpf_prog_entry *entry = &jmp_table.entries[i];
diff --git a/drivers/hid/bpf/hid_bpf_struct_ops.c b/drivers/hid/bpf/hid_bpf_struct_ops.c new file mode 100644 index 000000000000..be514a98e55b --- /dev/null +++ b/drivers/hid/bpf/hid_bpf_struct_ops.c @@ -0,0 +1,246 @@ +// SPDX-License-Identifier: GPL-2.0-only + +/* + * HID-BPF support for Linux + * + * Copyright (c) 2024 Benjamin Tissoires + */ + +#include <linux/bitops.h> +#include <linux/bpf_verifier.h> +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/btf_ids.h> +#include <linux/filter.h> +#include <linux/hid.h> +#include <linux/hid_bpf.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/workqueue.h> +#include "hid_bpf_dispatch.h" + +static struct btf *hid_bpf_ops_btf; + +static int hid_bpf_ops_init(struct btf *btf) +{ + hid_bpf_ops_btf = btf; + return 0; +} + +static bool hid_bpf_ops_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + return bpf_tracing_btf_ctx_access(off, size, type, prog, info); +} + +static int hid_bpf_ops_check_member(const struct btf_type *t, + const struct btf_member *member, + const struct bpf_prog *prog) +{ + u32 moff = __btf_member_bit_offset(t, member) / 8; + + switch (moff) { + case offsetof(struct hid_bpf_ops, hid_rdesc_fixup): + break; + default: + if (prog->sleepable) + return -EINVAL; + } + + return 0; +} + +static int hid_bpf_ops_btf_struct_access(struct bpf_verifier_log *log, + const struct bpf_reg_state *reg, + int off, int size) +{ + const struct btf_type *state; + const struct btf_type *t; + s32 type_id; + + type_id = btf_find_by_name_kind(reg->btf, "hid_bpf_ctx", + BTF_KIND_STRUCT); + if (type_id < 0) + return -EINVAL; + + t = btf_type_by_id(reg->btf, reg->btf_id); + state = btf_type_by_id(reg->btf, type_id); + if (t != state) { + bpf_log(log, "only access to hid_bpf_ctx is supported\n"); + return -EACCES; + } + + /* out-of-bound access in hid_bpf_ctx */ + if (off + size > sizeof(struct hid_bpf_ctx)) { + bpf_log(log, "write access at off %d with size %d\n", off, size); + return -EACCES; + } + + if (off < offsetof(struct hid_bpf_ctx, retval)) { + bpf_log(log, + "write access at off %d with size %d on read-only part of hid_bpf_ctx\n", + off, size); + return -EACCES; + } + + return NOT_INIT; +} + +static const struct bpf_verifier_ops hid_bpf_verifier_ops = { + .is_valid_access = hid_bpf_ops_is_valid_access, + .btf_struct_access = hid_bpf_ops_btf_struct_access, +}; + +static int hid_bpf_ops_init_member(const struct btf_type *t, + const struct btf_member *member, + void *kdata, const void *udata) +{ + u32 flags; + + switch (member->offset) { + case offsetof(struct hid_bpf_ops, hid_id) * 8: + /* For hid_id and flags fields, this function has to copy it + * and return 1 to indicate that the data has been handled by + * the struct_ops type, or the verifier will reject the map if + * the value of those fields is not zero. + */ + ((struct hid_bpf_ops *)kdata)->hid_id = ((struct hid_bpf_ops *)udata)->hid_id; + return 1; + case offsetof(struct hid_bpf_ops, flags) * 8: + flags = ((struct hid_bpf_ops *)udata)->flags; + if (flags & ~HID_BPF_FLAG_MASK) + return -EINVAL; + ((struct hid_bpf_ops *)kdata)->flags = flags; + return 1; + } + return 0; +} + +static int hid_bpf_reg(void *kdata) +{ + struct hid_bpf_ops *ops = kdata; + struct hid_device *hdev; + int count, err = 0; + + hdev = hid_get_device(ops->hid_id); + if (IS_ERR(hdev)) + return PTR_ERR(hdev); + + ops->hdev = hdev; + + mutex_lock(&hdev->bpf.prog_list_lock); + + count = list_count_nodes(&hdev->bpf.prog_list); + if (count >= HID_BPF_MAX_PROGS_PER_DEV) { + err = -E2BIG; + goto out_unlock; + } + + if (ops->hid_rdesc_fixup) { + if (hdev->bpf.rdesc_ops) { + err = -EINVAL; + goto out_unlock; + } + + hdev->bpf.rdesc_ops = ops; + } + + if (ops->hid_device_event) { + err = hid_bpf_allocate_event_data(hdev); + if (err) + goto out_unlock; + } + + if (ops->flags & HID_BPF_FLAG_INSERT_HEAD) + list_add_rcu(&ops->list, &hdev->bpf.prog_list); + else + list_add_tail_rcu(&ops->list, &hdev->bpf.prog_list); + +out_unlock: + mutex_unlock(&hdev->bpf.prog_list_lock); + + if (err) { + if (hdev->bpf.rdesc_ops == ops) + hdev->bpf.rdesc_ops = NULL; + hid_put_device(hdev); + } else if (ops->hid_rdesc_fixup) { + hid_bpf_reconnect(hdev); + } + + return err; +} + +static void hid_bpf_unreg(void *kdata) +{ + struct hid_bpf_ops *ops = kdata; + struct hid_device *hdev; + bool reconnect = false; + + hdev = ops->hdev; + + /* check if __hid_bpf_ops_destroy_device() has been called */ + if (!hdev) + return; + + mutex_lock(&hdev->bpf.prog_list_lock); + + list_del_rcu(&ops->list); + + reconnect = hdev->bpf.rdesc_ops == ops; + if (reconnect) + hdev->bpf.rdesc_ops = NULL; + + mutex_unlock(&hdev->bpf.prog_list_lock); + + if (reconnect) + hid_bpf_reconnect(hdev); + + hid_put_device(hdev); +} + +static int __hid_bpf_device_event(struct hid_bpf_ctx *ctx, enum hid_report_type type) +{ + return 0; +} + +static int __hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx) +{ + return 0; +} + +static struct hid_bpf_ops __bpf_hid_bpf_ops = { + .hid_device_event = __hid_bpf_device_event, + .hid_rdesc_fixup = __hid_bpf_rdesc_fixup, +}; + +static struct bpf_struct_ops bpf_hid_bpf_ops = { + .verifier_ops = &hid_bpf_verifier_ops, + .init = hid_bpf_ops_init, + .check_member = hid_bpf_ops_check_member, + .init_member = hid_bpf_ops_init_member, + .reg = hid_bpf_reg, + .unreg = hid_bpf_unreg, + .name = "hid_bpf_ops", + .cfi_stubs = &__bpf_hid_bpf_ops, + .owner = THIS_MODULE, +}; + +void __hid_bpf_ops_destroy_device(struct hid_device *hdev) +{ + struct hid_bpf_ops *e; + + rcu_read_lock(); + list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) { + hid_put_device(hdev); + e->hdev = NULL; + } + rcu_read_unlock(); +} + +static int __init hid_bpf_struct_ops_init(void) +{ + return register_bpf_struct_ops(&bpf_hid_bpf_ops, hid_bpf_ops); +} +late_initcall(hid_bpf_struct_ops_init); diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index a66103618e6e..96495e977204 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -65,11 +65,12 @@ struct hid_bpf_ctx { * @HID_BPF_FLAG_INSERT_HEAD: insert the given program before any other program * currently attached to the device. This doesn't * guarantee that this program will always be first - * @HID_BPF_FLAG_MAX: sentinel value, not to be used by the callers */ enum hid_bpf_attach_flags { HID_BPF_FLAG_NONE = 0, HID_BPF_FLAG_INSERT_HEAD = _BITUL(0), + + /* private: internal use only */ HID_BPF_FLAG_MAX, };
@@ -112,6 +113,63 @@ struct hid_ops {
extern struct hid_ops *hid_ops;
+/** + * struct hid_bpf_ops - A BPF struct_ops of callbacks allowing to attach HID-BPF + * programs to a HID device + * @hid_id: the HID uniq ID to attach to. This is writeable before ``load()``, and + * cannot be changed after + * @flags: &enum hid_bpf_attach_flags to assign flags before ``load()``. + * Writeable only before ``load()`` + */ +struct hid_bpf_ops { + /* hid_id needs to stay first so we can easily change it + * from userspace. + */ + int hid_id; + u32 flags; + + /* private: internal use only */ + struct list_head list; + + /* public: rest is public */ + +/* fast path fields are put first to fill one cache line */ + + /** + * @hid_device_event: called whenever an event is coming in from the device + * + * It has the following arguments: + * + * ``ctx``: The HID-BPF context as &struct hid_bpf_ctx + * + * Return: %0 on success and keep processing; a positive + * value to change the incoming size buffer; a negative + * error code to interrupt the processing of this event + * + * Context: Interrupt context. + */ + int (*hid_device_event)(struct hid_bpf_ctx *ctx, enum hid_report_type report_type); + +/* control/slow paths put last */ + + /** + * @hid_rdesc_fixup: called when the probe function parses the report descriptor + * of the HID device + * + * It has the following arguments: + * + * ``ctx``: The HID-BPF context as &struct hid_bpf_ctx + * + * Return: %0 on success and keep processing; a positive + * value to change the incoming size buffer; a negative + * error code to interrupt the processing of this device + */ + int (*hid_rdesc_fixup)(struct hid_bpf_ctx *ctx); + + /* private: internal use only */ + struct hid_device *hdev; +} ____cacheline_aligned_in_smp; + struct hid_bpf_prog_list { u16 prog_idx[HID_BPF_MAX_PROGS_PER_DEV]; u8 prog_cnt; @@ -129,6 +187,10 @@ struct hid_bpf { bool destroyed; /* prevents the assignment of any progs */
spinlock_t progs_lock; /* protects RCU update of progs */ + + struct hid_bpf_ops *rdesc_ops; + struct list_head prog_list; + struct mutex prog_list_lock; /* protects RCU update of prog_list */ };
/* specific HID-BPF link when a program is attached to a device */
On Tue, May 28, 2024 at 6:15 AM Benjamin Tissoires bentiss@kernel.org wrote:
We do this implementation in several steps to not have the CI failing:
- first (this patch), we add struct_ops while keeping the existing infra available
- then we change the selftests, the examples and the existing in-tree HID-BPF programs
- then we remove the existing trace points making old HID-BPF obsolete
There are a few advantages of struct_ops over tracing:
- compatibility with sleepable programs (for hid_hw_raw_request() in a later patch)
- a lot simpler in the kernel: it's a simple rcu protected list
- we can add more parameters to the function called without much trouble
- the "attach" is now generic through BPF-core: the caller just needs to set hid_id and flags before calling __load().
- all the BPF tough part is not handled in BPF-core through generic processing
- hid_bpf_ctx is now only writable where it needs be
Signed-off-by: Benjamin Tissoires bentiss@kernel.org
drivers/hid/bpf/Makefile | 2 +- drivers/hid/bpf/hid_bpf_dispatch.c | 52 +++++++- drivers/hid/bpf/hid_bpf_dispatch.h | 4 + drivers/hid/bpf/hid_bpf_jmp_table.c | 3 + drivers/hid/bpf/hid_bpf_struct_ops.c | 246 +++++++++++++++++++++++++++++++++++ include/linux/hid_bpf.h | 64 ++++++++- 6 files changed, 362 insertions(+), 9 deletions(-)
diff --git a/drivers/hid/bpf/Makefile b/drivers/hid/bpf/Makefile index cf55120cf7d6..1cb3f31e9335 100644 --- a/drivers/hid/bpf/Makefile +++ b/drivers/hid/bpf/Makefile @@ -8,4 +8,4 @@ LIBBPF_INCLUDE = $(srctree)/tools/lib obj-$(CONFIG_HID_BPF) += hid_bpf.o CFLAGS_hid_bpf_dispatch.o += -I$(LIBBPF_INCLUDE) CFLAGS_hid_bpf_jmp_table.o += -I$(LIBBPF_INCLUDE) -hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_jmp_table.o +hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_jmp_table.o hid_bpf_struct_ops.o diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index c8bb79ce2354..7216c3c7713d 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -58,6 +58,7 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type }, .data = hdev->bpf.device_data, };
struct hid_bpf_ops *e; int ret; if (type >= HID_REPORT_TYPES)@@ -70,9 +71,25 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type memset(ctx_kern.data, 0, hdev->bpf.allocated_data); memcpy(ctx_kern.data, data, *size);
rcu_read_lock();list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) {
In the typical case there will be only one prog per device, right? The for_each is future proofing?
if (e->hid_device_event) {ret = e->hid_device_event(&ctx_kern.ctx, type);if (ret < 0) {rcu_read_unlock();return ERR_PTR(ret);}if (ret)ctx_kern.ctx.retval = ret;}}rcu_read_unlock();ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_DEVICE_EVENT, &ctx_kern); if (ret < 0) return ERR_PTR(ret);ret = ctx_kern.ctx.retval; if (ret) { if (ret > ctx_kern.ctx.allocated_size)@@ -122,7 +139,10 @@ u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *s
memcpy(ctx_kern.data, rdesc, min_t(unsigned int, *size, HID_MAX_DESCRIPTOR_SIZE));
ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern);
if (hdev->bpf.rdesc_ops)ret = hdev->bpf.rdesc_ops->hid_rdesc_fixup(&ctx_kern.ctx);elseret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern);
This is for backward compat? I don't see it's being removed in the later patches.
if (ret < 0) goto ignore_bpf;@@ -150,7 +170,7 @@ static int device_match_id(struct device *dev, const void *id) return hdev->id == *(int *)id; }
-static struct hid_device *hid_get_device(unsigned int hid_id) +struct hid_device *hid_get_device(unsigned int hid_id) { struct device *dev;
@@ -164,7 +184,7 @@ static struct hid_device *hid_get_device(unsigned int hid_id) return to_hid_device(dev); }
-static void hid_put_device(struct hid_device *hid) +void hid_put_device(struct hid_device *hid) { put_device(&hid->dev); } @@ -205,7 +225,7 @@ static int __hid_bpf_allocate_data(struct hid_device *hdev, u8 **data, u32 *size return 0; }
-static int hid_bpf_allocate_event_data(struct hid_device *hdev) +int hid_bpf_allocate_event_data(struct hid_device *hdev) { /* hdev->bpf.device_data is already allocated, abort */ if (hdev->bpf.device_data) @@ -592,14 +612,22 @@ static const struct btf_kfunc_id_set hid_bpf_syscall_kfunc_set = {
int hid_bpf_connect_device(struct hid_device *hdev) {
struct hid_bpf_prog_list *prog_list;
bool need_to_allocate = false;struct hid_bpf_ops *e; rcu_read_lock();
prog_list = rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT]);
list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) {if (e->hid_device_event) {need_to_allocate = true;break;}}if (rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT]))need_to_allocate = true; rcu_read_unlock(); /* only allocate BPF data if there are programs attached */
if (!prog_list)
if (!need_to_allocate) return 0; return hid_bpf_allocate_event_data(hdev);@@ -623,12 +651,15 @@ void hid_bpf_destroy_device(struct hid_device *hdev) hdev->bpf.destroyed = true;
__hid_bpf_destroy_device(hdev);
__hid_bpf_ops_destroy_device(hdev);} EXPORT_SYMBOL_GPL(hid_bpf_destroy_device);
void hid_bpf_device_init(struct hid_device *hdev) { spin_lock_init(&hdev->bpf.progs_lock);
INIT_LIST_HEAD(&hdev->bpf.prog_list);mutex_init(&hdev->bpf.prog_list_lock);} EXPORT_SYMBOL_GPL(hid_bpf_device_init);
@@ -662,6 +693,13 @@ static int __init hid_bpf_init(void) return 0; }
/* register struct_ops kfuncs after we are sure we can load our preloaded bpf program */err = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &hid_bpf_kfunc_set);if (err) {pr_warn("error while setting HID BPF tracing kfuncs: %d", err);return 0;}/* register syscalls after we are sure we can load our preloaded bpf program */ err = register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &hid_bpf_syscall_kfunc_set); if (err) {diff --git a/drivers/hid/bpf/hid_bpf_dispatch.h b/drivers/hid/bpf/hid_bpf_dispatch.h index fbe0639d09f2..e52c43d81650 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.h +++ b/drivers/hid/bpf/hid_bpf_dispatch.h @@ -10,12 +10,16 @@ struct hid_bpf_ctx_kern { u8 *data; };
+struct hid_device *hid_get_device(unsigned int hid_id); +void hid_put_device(struct hid_device *hid); +int hid_bpf_allocate_event_data(struct hid_device *hdev); int hid_bpf_preload_skel(void); void hid_bpf_free_links_and_skel(void); int hid_bpf_get_prog_attach_type(struct bpf_prog *prog); int __hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_type, int prog_fd, struct bpf_prog *prog, __u32 flags); void __hid_bpf_destroy_device(struct hid_device *hdev); +void __hid_bpf_ops_destroy_device(struct hid_device *hdev); int hid_bpf_prog_run(struct hid_device *hdev, enum hid_bpf_prog_type type, struct hid_bpf_ctx_kern *ctx_kern); int hid_bpf_reconnect(struct hid_device *hdev); diff --git a/drivers/hid/bpf/hid_bpf_jmp_table.c b/drivers/hid/bpf/hid_bpf_jmp_table.c index aa8e1c79cdf5..8a54ba447718 100644 --- a/drivers/hid/bpf/hid_bpf_jmp_table.c +++ b/drivers/hid/bpf/hid_bpf_jmp_table.c @@ -81,6 +81,9 @@ static int hid_bpf_program_count(struct hid_device *hdev, if (type >= HID_BPF_PROG_TYPE_MAX) return -EINVAL;
if (type == HID_BPF_PROG_TYPE_RDESC_FIXUP && hdev->bpf.rdesc_ops)n += 1;FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { struct hid_bpf_prog_entry *entry = &jmp_table.entries[i];diff --git a/drivers/hid/bpf/hid_bpf_struct_ops.c b/drivers/hid/bpf/hid_bpf_struct_ops.c new file mode 100644 index 000000000000..be514a98e55b --- /dev/null +++ b/drivers/hid/bpf/hid_bpf_struct_ops.c @@ -0,0 +1,246 @@ +// SPDX-License-Identifier: GPL-2.0-only
+/*
- HID-BPF support for Linux
- Copyright (c) 2024 Benjamin Tissoires
- */
+#include <linux/bitops.h> +#include <linux/bpf_verifier.h> +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/btf_ids.h> +#include <linux/filter.h> +#include <linux/hid.h> +#include <linux/hid_bpf.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/workqueue.h> +#include "hid_bpf_dispatch.h"
+static struct btf *hid_bpf_ops_btf;
+static int hid_bpf_ops_init(struct btf *btf) +{
hid_bpf_ops_btf = btf;return 0;+}
+static bool hid_bpf_ops_is_valid_access(int off, int size,
enum bpf_access_type type,const struct bpf_prog *prog,struct bpf_insn_access_aux *info)+{
return bpf_tracing_btf_ctx_access(off, size, type, prog, info);+}
+static int hid_bpf_ops_check_member(const struct btf_type *t,
const struct btf_member *member,const struct bpf_prog *prog)+{
u32 moff = __btf_member_bit_offset(t, member) / 8;
this is good...
switch (moff) {case offsetof(struct hid_bpf_ops, hid_rdesc_fixup):break;default:if (prog->sleepable)return -EINVAL;}return 0;+}
+static int hid_bpf_ops_btf_struct_access(struct bpf_verifier_log *log,
const struct bpf_reg_state *reg,int off, int size)+{
const struct btf_type *state;const struct btf_type *t;s32 type_id;type_id = btf_find_by_name_kind(reg->btf, "hid_bpf_ctx",BTF_KIND_STRUCT);if (type_id < 0)return -EINVAL;t = btf_type_by_id(reg->btf, reg->btf_id);state = btf_type_by_id(reg->btf, type_id);if (t != state) {bpf_log(log, "only access to hid_bpf_ctx is supported\n");return -EACCES;}/* out-of-bound access in hid_bpf_ctx */if (off + size > sizeof(struct hid_bpf_ctx)) {bpf_log(log, "write access at off %d with size %d\n", off, size);return -EACCES;}if (off < offsetof(struct hid_bpf_ctx, retval)) {bpf_log(log,"write access at off %d with size %d on read-only part of hid_bpf_ctx\n",off, size);return -EACCES;}return NOT_INIT;+}
+static const struct bpf_verifier_ops hid_bpf_verifier_ops = {
.is_valid_access = hid_bpf_ops_is_valid_access,.btf_struct_access = hid_bpf_ops_btf_struct_access,+};
+static int hid_bpf_ops_init_member(const struct btf_type *t,
const struct btf_member *member,void *kdata, const void *udata)+{
u32 flags;switch (member->offset) {case offsetof(struct hid_bpf_ops, hid_id) * 8:
but here you're open coding it and adding ugly * 8 Just do: moff = __btf_member_bit_offset(t, member) / 8; switch (moff) { case offsetof(struct tcp_congestion_ops, flags):
the way bpf_tcp_ca.c is doing? Open code of ->offset is asking for trouble.
/* For hid_id and flags fields, this function has to copy it* and return 1 to indicate that the data has been handled by* the struct_ops type, or the verifier will reject the map if* the value of those fields is not zero.*/((struct hid_bpf_ops *)kdata)->hid_id = ((struct hid_bpf_ops *)udata)->hid_id;return 1;case offsetof(struct hid_bpf_ops, flags) * 8:flags = ((struct hid_bpf_ops *)udata)->flags;if (flags & ~HID_BPF_FLAG_MASK)return -EINVAL;((struct hid_bpf_ops *)kdata)->flags = flags;return 1;}return 0;+}
+static int hid_bpf_reg(void *kdata) +{
struct hid_bpf_ops *ops = kdata;struct hid_device *hdev;int count, err = 0;hdev = hid_get_device(ops->hid_id);if (IS_ERR(hdev))return PTR_ERR(hdev);ops->hdev = hdev;mutex_lock(&hdev->bpf.prog_list_lock);count = list_count_nodes(&hdev->bpf.prog_list);if (count >= HID_BPF_MAX_PROGS_PER_DEV) {err = -E2BIG;goto out_unlock;}if (ops->hid_rdesc_fixup) {if (hdev->bpf.rdesc_ops) {err = -EINVAL;goto out_unlock;}hdev->bpf.rdesc_ops = ops;}if (ops->hid_device_event) {err = hid_bpf_allocate_event_data(hdev);if (err)goto out_unlock;}if (ops->flags & HID_BPF_FLAG_INSERT_HEAD)list_add_rcu(&ops->list, &hdev->bpf.prog_list);elselist_add_tail_rcu(&ops->list, &hdev->bpf.prog_list);
Looks like future proofing, but I feel it's too little to materialize. Take a look at include/linux/bpf_mprog.h I suspect it might be useful here too.
+out_unlock:
mutex_unlock(&hdev->bpf.prog_list_lock);if (err) {if (hdev->bpf.rdesc_ops == ops)hdev->bpf.rdesc_ops = NULL;hid_put_device(hdev);} else if (ops->hid_rdesc_fixup) {hid_bpf_reconnect(hdev);}return err;+}
+static void hid_bpf_unreg(void *kdata) +{
struct hid_bpf_ops *ops = kdata;struct hid_device *hdev;bool reconnect = false;hdev = ops->hdev;/* check if __hid_bpf_ops_destroy_device() has been called */if (!hdev)return;mutex_lock(&hdev->bpf.prog_list_lock);list_del_rcu(&ops->list);reconnect = hdev->bpf.rdesc_ops == ops;if (reconnect)hdev->bpf.rdesc_ops = NULL;mutex_unlock(&hdev->bpf.prog_list_lock);if (reconnect)hid_bpf_reconnect(hdev);hid_put_device(hdev);+}
+static int __hid_bpf_device_event(struct hid_bpf_ctx *ctx, enum hid_report_type type) +{
return 0;+}
+static int __hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx) +{
return 0;+}
+static struct hid_bpf_ops __bpf_hid_bpf_ops = {
.hid_device_event = __hid_bpf_device_event,.hid_rdesc_fixup = __hid_bpf_rdesc_fixup,+};
+static struct bpf_struct_ops bpf_hid_bpf_ops = {
.verifier_ops = &hid_bpf_verifier_ops,.init = hid_bpf_ops_init,.check_member = hid_bpf_ops_check_member,.init_member = hid_bpf_ops_init_member,.reg = hid_bpf_reg,.unreg = hid_bpf_unreg,.name = "hid_bpf_ops",.cfi_stubs = &__bpf_hid_bpf_ops,.owner = THIS_MODULE,+};
+void __hid_bpf_ops_destroy_device(struct hid_device *hdev) +{
struct hid_bpf_ops *e;rcu_read_lock();list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) {hid_put_device(hdev);e->hdev = NULL;}rcu_read_unlock();+}
+static int __init hid_bpf_struct_ops_init(void) +{
return register_bpf_struct_ops(&bpf_hid_bpf_ops, hid_bpf_ops);+} +late_initcall(hid_bpf_struct_ops_init); diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index a66103618e6e..96495e977204 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -65,11 +65,12 @@ struct hid_bpf_ctx {
- @HID_BPF_FLAG_INSERT_HEAD: insert the given program before any other program
currently attached to the device. This doesn'tguarantee that this program will always be first
*/
- @HID_BPF_FLAG_MAX: sentinel value, not to be used by the callers
enum hid_bpf_attach_flags { HID_BPF_FLAG_NONE = 0, HID_BPF_FLAG_INSERT_HEAD = _BITUL(0),
/* private: internal use only */ HID_BPF_FLAG_MAX,};
@@ -112,6 +113,63 @@ struct hid_ops {
extern struct hid_ops *hid_ops;
+/**
- struct hid_bpf_ops - A BPF struct_ops of callbacks allowing to attach HID-BPF
programs to a HID device
- @hid_id: the HID uniq ID to attach to. This is writeable before ``load()``, and
cannot be changed after
- @flags: &enum hid_bpf_attach_flags to assign flags before ``load()``.
Writeable only before ``load()``- */
+struct hid_bpf_ops {
/* hid_id needs to stay first so we can easily change it* from userspace.*/
hmm. patch 5 just does: + skel->struct_ops.mouse_invert->hid_id = hid_id;
I don't see a reason why it needs to be first.
int hid_id;u32 flags;/* private: internal use only */struct list_head list;/* public: rest is public */+/* fast path fields are put first to fill one cache line */
/*** @hid_device_event: called whenever an event is coming in from the device** It has the following arguments:** ``ctx``: The HID-BPF context as &struct hid_bpf_ctx** Return: %0 on success and keep processing; a positive* value to change the incoming size buffer; a negative* error code to interrupt the processing of this event** Context: Interrupt context.*/int (*hid_device_event)(struct hid_bpf_ctx *ctx, enum hid_report_type report_type);+/* control/slow paths put last */
/*** @hid_rdesc_fixup: called when the probe function parses the report descriptor* of the HID device** It has the following arguments:** ``ctx``: The HID-BPF context as &struct hid_bpf_ctx** Return: %0 on success and keep processing; a positive* value to change the incoming size buffer; a negative* error code to interrupt the processing of this device*/int (*hid_rdesc_fixup)(struct hid_bpf_ctx *ctx);
It's fine since you want to keep the prog mostly unchanged, but since the whole api is improving maybe it's time to do something about hid_bpf_ctx in all callbacks? Pass into prog what prog needs to see. In the old api all progs had to have a common hid_bpf_ctx. With struct-ops it can be fine tuned.
Overall it looks great. hid_id did the trick :)
On May 28 2024, Alexei Starovoitov wrote:
On Tue, May 28, 2024 at 6:15 AM Benjamin Tissoires bentiss@kernel.org wrote:
We do this implementation in several steps to not have the CI failing:
- first (this patch), we add struct_ops while keeping the existing infra available
- then we change the selftests, the examples and the existing in-tree HID-BPF programs
- then we remove the existing trace points making old HID-BPF obsolete
There are a few advantages of struct_ops over tracing:
- compatibility with sleepable programs (for hid_hw_raw_request() in a later patch)
- a lot simpler in the kernel: it's a simple rcu protected list
- we can add more parameters to the function called without much trouble
- the "attach" is now generic through BPF-core: the caller just needs to set hid_id and flags before calling __load().
- all the BPF tough part is not handled in BPF-core through generic processing
- hid_bpf_ctx is now only writable where it needs be
Signed-off-by: Benjamin Tissoires bentiss@kernel.org
drivers/hid/bpf/Makefile | 2 +- drivers/hid/bpf/hid_bpf_dispatch.c | 52 +++++++- drivers/hid/bpf/hid_bpf_dispatch.h | 4 + drivers/hid/bpf/hid_bpf_jmp_table.c | 3 + drivers/hid/bpf/hid_bpf_struct_ops.c | 246 +++++++++++++++++++++++++++++++++++ include/linux/hid_bpf.h | 64 ++++++++- 6 files changed, 362 insertions(+), 9 deletions(-)
diff --git a/drivers/hid/bpf/Makefile b/drivers/hid/bpf/Makefile index cf55120cf7d6..1cb3f31e9335 100644 --- a/drivers/hid/bpf/Makefile +++ b/drivers/hid/bpf/Makefile @@ -8,4 +8,4 @@ LIBBPF_INCLUDE = $(srctree)/tools/lib obj-$(CONFIG_HID_BPF) += hid_bpf.o CFLAGS_hid_bpf_dispatch.o += -I$(LIBBPF_INCLUDE) CFLAGS_hid_bpf_jmp_table.o += -I$(LIBBPF_INCLUDE) -hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_jmp_table.o +hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_jmp_table.o hid_bpf_struct_ops.o diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index c8bb79ce2354..7216c3c7713d 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -58,6 +58,7 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type }, .data = hdev->bpf.device_data, };
struct hid_bpf_ops *e; int ret; if (type >= HID_REPORT_TYPES)@@ -70,9 +71,25 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type memset(ctx_kern.data, 0, hdev->bpf.allocated_data); memcpy(ctx_kern.data, data, *size);
rcu_read_lock();list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) {In the typical case there will be only one prog per device, right?
90% of the time there is only one prog per device, but I need to have more than one for the following reasons: - when one prog is loaded, the output data gets modified, so to be able to access the raw data from the device I need to add a "tracing" program *before* the one that changes data to forward raw data to userspace - we already have situation where for convenience multiple programs are attached to one device (see drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c) - once firewalling will be in place, we will likely have one program for the firewall and one for the device fix
The for_each is future proofing?
if (e->hid_device_event) {ret = e->hid_device_event(&ctx_kern.ctx, type);if (ret < 0) {rcu_read_unlock();return ERR_PTR(ret);}if (ret)ctx_kern.ctx.retval = ret;}}rcu_read_unlock();ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_DEVICE_EVENT, &ctx_kern); if (ret < 0) return ERR_PTR(ret);ret = ctx_kern.ctx.retval; if (ret) { if (ret > ctx_kern.ctx.allocated_size)@@ -122,7 +139,10 @@ u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *s
memcpy(ctx_kern.data, rdesc, min_t(unsigned int, *size, HID_MAX_DESCRIPTOR_SIZE));
ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern);
if (hdev->bpf.rdesc_ops)ret = hdev->bpf.rdesc_ops->hid_rdesc_fixup(&ctx_kern.ctx);elseret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern);This is for backward compat?
yes
I don't see it's being removed in the later patches.
see patch 8/13, all the tracing capabilities are gone.
I made a backward compatibility step here so I do not break the selftests while changing the API.
if (ret < 0) goto ignore_bpf;@@ -150,7 +170,7 @@ static int device_match_id(struct device *dev, const void *id) return hdev->id == *(int *)id; }
-static struct hid_device *hid_get_device(unsigned int hid_id) +struct hid_device *hid_get_device(unsigned int hid_id) { struct device *dev;
@@ -164,7 +184,7 @@ static struct hid_device *hid_get_device(unsigned int hid_id) return to_hid_device(dev); }
-static void hid_put_device(struct hid_device *hid) +void hid_put_device(struct hid_device *hid) { put_device(&hid->dev); } @@ -205,7 +225,7 @@ static int __hid_bpf_allocate_data(struct hid_device *hdev, u8 **data, u32 *size return 0; }
-static int hid_bpf_allocate_event_data(struct hid_device *hdev) +int hid_bpf_allocate_event_data(struct hid_device *hdev) { /* hdev->bpf.device_data is already allocated, abort */ if (hdev->bpf.device_data) @@ -592,14 +612,22 @@ static const struct btf_kfunc_id_set hid_bpf_syscall_kfunc_set = {
int hid_bpf_connect_device(struct hid_device *hdev) {
struct hid_bpf_prog_list *prog_list;
bool need_to_allocate = false;struct hid_bpf_ops *e; rcu_read_lock();
prog_list = rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT]);
list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) {if (e->hid_device_event) {need_to_allocate = true;break;}}if (rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT]))need_to_allocate = true; rcu_read_unlock(); /* only allocate BPF data if there are programs attached */
if (!prog_list)
if (!need_to_allocate) return 0; return hid_bpf_allocate_event_data(hdev);@@ -623,12 +651,15 @@ void hid_bpf_destroy_device(struct hid_device *hdev) hdev->bpf.destroyed = true;
__hid_bpf_destroy_device(hdev);
__hid_bpf_ops_destroy_device(hdev);} EXPORT_SYMBOL_GPL(hid_bpf_destroy_device);
void hid_bpf_device_init(struct hid_device *hdev) { spin_lock_init(&hdev->bpf.progs_lock);
INIT_LIST_HEAD(&hdev->bpf.prog_list);mutex_init(&hdev->bpf.prog_list_lock);} EXPORT_SYMBOL_GPL(hid_bpf_device_init);
@@ -662,6 +693,13 @@ static int __init hid_bpf_init(void) return 0; }
/* register struct_ops kfuncs after we are sure we can load our preloaded bpf program */err = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &hid_bpf_kfunc_set);if (err) {pr_warn("error while setting HID BPF tracing kfuncs: %d", err);return 0;}/* register syscalls after we are sure we can load our preloaded bpf program */ err = register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &hid_bpf_syscall_kfunc_set); if (err) {diff --git a/drivers/hid/bpf/hid_bpf_dispatch.h b/drivers/hid/bpf/hid_bpf_dispatch.h index fbe0639d09f2..e52c43d81650 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.h +++ b/drivers/hid/bpf/hid_bpf_dispatch.h @@ -10,12 +10,16 @@ struct hid_bpf_ctx_kern { u8 *data; };
+struct hid_device *hid_get_device(unsigned int hid_id); +void hid_put_device(struct hid_device *hid); +int hid_bpf_allocate_event_data(struct hid_device *hdev); int hid_bpf_preload_skel(void); void hid_bpf_free_links_and_skel(void); int hid_bpf_get_prog_attach_type(struct bpf_prog *prog); int __hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_type, int prog_fd, struct bpf_prog *prog, __u32 flags); void __hid_bpf_destroy_device(struct hid_device *hdev); +void __hid_bpf_ops_destroy_device(struct hid_device *hdev); int hid_bpf_prog_run(struct hid_device *hdev, enum hid_bpf_prog_type type, struct hid_bpf_ctx_kern *ctx_kern); int hid_bpf_reconnect(struct hid_device *hdev); diff --git a/drivers/hid/bpf/hid_bpf_jmp_table.c b/drivers/hid/bpf/hid_bpf_jmp_table.c index aa8e1c79cdf5..8a54ba447718 100644 --- a/drivers/hid/bpf/hid_bpf_jmp_table.c +++ b/drivers/hid/bpf/hid_bpf_jmp_table.c @@ -81,6 +81,9 @@ static int hid_bpf_program_count(struct hid_device *hdev, if (type >= HID_BPF_PROG_TYPE_MAX) return -EINVAL;
if (type == HID_BPF_PROG_TYPE_RDESC_FIXUP && hdev->bpf.rdesc_ops)n += 1;FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { struct hid_bpf_prog_entry *entry = &jmp_table.entries[i];diff --git a/drivers/hid/bpf/hid_bpf_struct_ops.c b/drivers/hid/bpf/hid_bpf_struct_ops.c new file mode 100644 index 000000000000..be514a98e55b --- /dev/null +++ b/drivers/hid/bpf/hid_bpf_struct_ops.c @@ -0,0 +1,246 @@ +// SPDX-License-Identifier: GPL-2.0-only
+/*
- HID-BPF support for Linux
- Copyright (c) 2024 Benjamin Tissoires
- */
+#include <linux/bitops.h> +#include <linux/bpf_verifier.h> +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/btf_ids.h> +#include <linux/filter.h> +#include <linux/hid.h> +#include <linux/hid_bpf.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/workqueue.h> +#include "hid_bpf_dispatch.h"
+static struct btf *hid_bpf_ops_btf;
+static int hid_bpf_ops_init(struct btf *btf) +{
hid_bpf_ops_btf = btf;return 0;+}
+static bool hid_bpf_ops_is_valid_access(int off, int size,
enum bpf_access_type type,const struct bpf_prog *prog,struct bpf_insn_access_aux *info)+{
return bpf_tracing_btf_ctx_access(off, size, type, prog, info);+}
+static int hid_bpf_ops_check_member(const struct btf_type *t,
const struct btf_member *member,const struct bpf_prog *prog)+{
u32 moff = __btf_member_bit_offset(t, member) / 8;this is good...
switch (moff) {case offsetof(struct hid_bpf_ops, hid_rdesc_fixup):break;default:if (prog->sleepable)return -EINVAL;}return 0;+}
+static int hid_bpf_ops_btf_struct_access(struct bpf_verifier_log *log,
const struct bpf_reg_state *reg,int off, int size)+{
const struct btf_type *state;const struct btf_type *t;s32 type_id;type_id = btf_find_by_name_kind(reg->btf, "hid_bpf_ctx",BTF_KIND_STRUCT);if (type_id < 0)return -EINVAL;t = btf_type_by_id(reg->btf, reg->btf_id);state = btf_type_by_id(reg->btf, type_id);if (t != state) {bpf_log(log, "only access to hid_bpf_ctx is supported\n");return -EACCES;}/* out-of-bound access in hid_bpf_ctx */if (off + size > sizeof(struct hid_bpf_ctx)) {bpf_log(log, "write access at off %d with size %d\n", off, size);return -EACCES;}if (off < offsetof(struct hid_bpf_ctx, retval)) {bpf_log(log,"write access at off %d with size %d on read-only part of hid_bpf_ctx\n",off, size);return -EACCES;}return NOT_INIT;+}
+static const struct bpf_verifier_ops hid_bpf_verifier_ops = {
.is_valid_access = hid_bpf_ops_is_valid_access,.btf_struct_access = hid_bpf_ops_btf_struct_access,+};
+static int hid_bpf_ops_init_member(const struct btf_type *t,
const struct btf_member *member,void *kdata, const void *udata)+{
u32 flags;switch (member->offset) {case offsetof(struct hid_bpf_ops, hid_id) * 8:but here you're open coding it and adding ugly * 8 Just do: moff = __btf_member_bit_offset(t, member) / 8; switch (moff) { case offsetof(struct tcp_congestion_ops, flags):
the way bpf_tcp_ca.c is doing? Open code of ->offset is asking for trouble.
heh, I just monkey-copied tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
Will change it :)
/* For hid_id and flags fields, this function has to copy it* and return 1 to indicate that the data has been handled by* the struct_ops type, or the verifier will reject the map if* the value of those fields is not zero.*/((struct hid_bpf_ops *)kdata)->hid_id = ((struct hid_bpf_ops *)udata)->hid_id;return 1;case offsetof(struct hid_bpf_ops, flags) * 8:flags = ((struct hid_bpf_ops *)udata)->flags;if (flags & ~HID_BPF_FLAG_MASK)return -EINVAL;((struct hid_bpf_ops *)kdata)->flags = flags;return 1;}return 0;+}
+static int hid_bpf_reg(void *kdata) +{
struct hid_bpf_ops *ops = kdata;struct hid_device *hdev;int count, err = 0;hdev = hid_get_device(ops->hid_id);if (IS_ERR(hdev))return PTR_ERR(hdev);ops->hdev = hdev;mutex_lock(&hdev->bpf.prog_list_lock);count = list_count_nodes(&hdev->bpf.prog_list);if (count >= HID_BPF_MAX_PROGS_PER_DEV) {err = -E2BIG;goto out_unlock;}if (ops->hid_rdesc_fixup) {if (hdev->bpf.rdesc_ops) {err = -EINVAL;goto out_unlock;}hdev->bpf.rdesc_ops = ops;}if (ops->hid_device_event) {err = hid_bpf_allocate_event_data(hdev);if (err)goto out_unlock;}if (ops->flags & HID_BPF_FLAG_INSERT_HEAD)list_add_rcu(&ops->list, &hdev->bpf.prog_list);elselist_add_tail_rcu(&ops->list, &hdev->bpf.prog_list);Looks like future proofing, but I feel it's too little to materialize.
again, the case already happens, so I need a list (or equivalent of) :)
Take a look at include/linux/bpf_mprog.h I suspect it might be useful here too.
From the quick look of it this is interesting, but for plain struct bpf_prog, right?
So I would have to adapt this include for struct_ops?
+out_unlock:
mutex_unlock(&hdev->bpf.prog_list_lock);if (err) {if (hdev->bpf.rdesc_ops == ops)hdev->bpf.rdesc_ops = NULL;hid_put_device(hdev);} else if (ops->hid_rdesc_fixup) {hid_bpf_reconnect(hdev);}return err;+}
+static void hid_bpf_unreg(void *kdata) +{
struct hid_bpf_ops *ops = kdata;struct hid_device *hdev;bool reconnect = false;hdev = ops->hdev;/* check if __hid_bpf_ops_destroy_device() has been called */if (!hdev)return;mutex_lock(&hdev->bpf.prog_list_lock);list_del_rcu(&ops->list);reconnect = hdev->bpf.rdesc_ops == ops;if (reconnect)hdev->bpf.rdesc_ops = NULL;mutex_unlock(&hdev->bpf.prog_list_lock);if (reconnect)hid_bpf_reconnect(hdev);hid_put_device(hdev);+}
+static int __hid_bpf_device_event(struct hid_bpf_ctx *ctx, enum hid_report_type type) +{
return 0;+}
+static int __hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx) +{
return 0;+}
+static struct hid_bpf_ops __bpf_hid_bpf_ops = {
.hid_device_event = __hid_bpf_device_event,.hid_rdesc_fixup = __hid_bpf_rdesc_fixup,+};
+static struct bpf_struct_ops bpf_hid_bpf_ops = {
.verifier_ops = &hid_bpf_verifier_ops,.init = hid_bpf_ops_init,.check_member = hid_bpf_ops_check_member,.init_member = hid_bpf_ops_init_member,.reg = hid_bpf_reg,.unreg = hid_bpf_unreg,.name = "hid_bpf_ops",.cfi_stubs = &__bpf_hid_bpf_ops,.owner = THIS_MODULE,+};
+void __hid_bpf_ops_destroy_device(struct hid_device *hdev) +{
struct hid_bpf_ops *e;rcu_read_lock();list_for_each_entry_rcu(e, &hdev->bpf.prog_list, list) {hid_put_device(hdev);e->hdev = NULL;}rcu_read_unlock();+}
+static int __init hid_bpf_struct_ops_init(void) +{
return register_bpf_struct_ops(&bpf_hid_bpf_ops, hid_bpf_ops);+} +late_initcall(hid_bpf_struct_ops_init); diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index a66103618e6e..96495e977204 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -65,11 +65,12 @@ struct hid_bpf_ctx {
- @HID_BPF_FLAG_INSERT_HEAD: insert the given program before any other program
currently attached to the device. This doesn'tguarantee that this program will always be first
*/
- @HID_BPF_FLAG_MAX: sentinel value, not to be used by the callers
enum hid_bpf_attach_flags { HID_BPF_FLAG_NONE = 0, HID_BPF_FLAG_INSERT_HEAD = _BITUL(0),
/* private: internal use only */ HID_BPF_FLAG_MAX,};
@@ -112,6 +113,63 @@ struct hid_ops {
extern struct hid_ops *hid_ops;
+/**
- struct hid_bpf_ops - A BPF struct_ops of callbacks allowing to attach HID-BPF
programs to a HID device
- @hid_id: the HID uniq ID to attach to. This is writeable before ``load()``, and
cannot be changed after
- @flags: &enum hid_bpf_attach_flags to assign flags before ``load()``.
Writeable only before ``load()``- */
+struct hid_bpf_ops {
/* hid_id needs to stay first so we can easily change it* from userspace.*/hmm. patch 5 just does:
skel->struct_ops.mouse_invert->hid_id = hid_id;I don't see a reason why it needs to be first.
See the selftests (and my external loader, udev-hid-bpf):
map = bpf_object__find_map_by_name(*self->skel->skeleton->obj, programs[i].name + 4); ASSERT_OK_PTR(map) TH_LOG("can not find struct_ops by name '%s'", programs[i].name + 4);
/* hid_id is the first field of struct hid_bpf_ops */ ops_hid_id = bpf_map__initial_value(map, NULL); ASSERT_OK_PTR(ops_hid_id) TH_LOG("unable to retrieve struct_ops data");
*ops_hid_id = self->hid_id;
Basically, I want to have to deal with .bpf.o and not the skeletons for the generic case. I want to be able to drop a file in /lib/firmware/hid and have udev-hid-bpf load it without having to recompile udev-hid-bpf.
I couldn't seem to be able to access the struct_ops BTF information from libbpf, so I decided to have hid_id and flags first and consider this to be ABI while I figure out how to get to the real offsets :)
int hid_id;u32 flags;/* private: internal use only */struct list_head list;/* public: rest is public */+/* fast path fields are put first to fill one cache line */
/*** @hid_device_event: called whenever an event is coming in from the device** It has the following arguments:** ``ctx``: The HID-BPF context as &struct hid_bpf_ctx** Return: %0 on success and keep processing; a positive* value to change the incoming size buffer; a negative* error code to interrupt the processing of this event** Context: Interrupt context.*/int (*hid_device_event)(struct hid_bpf_ctx *ctx, enum hid_report_type report_type);+/* control/slow paths put last */
/*** @hid_rdesc_fixup: called when the probe function parses the report descriptor* of the HID device** It has the following arguments:** ``ctx``: The HID-BPF context as &struct hid_bpf_ctx** Return: %0 on success and keep processing; a positive* value to change the incoming size buffer; a negative* error code to interrupt the processing of this device*/int (*hid_rdesc_fixup)(struct hid_bpf_ctx *ctx);It's fine since you want to keep the prog mostly unchanged, but since the whole api is improving maybe it's time to do something about hid_bpf_ctx in all callbacks? Pass into prog what prog needs to see. In the old api all progs had to have a common hid_bpf_ctx. With struct-ops it can be fine tuned.
I agree, but I had a few cons: - right now, I can recompile the same bpf.c with just a -D in the cflags. Both types of program are compatible, which allows to write the file once and recompile it for both pre/post struct_ops. This will be very useful while HID-BPF struct_ops is not in mainline distributions - I need to have access to a few things: the struct hid_device, and the incoming buffer. And I don't think I can teach the verifier about the incoming buffer size without having to store it into a dedicated struct, which results into the same hid_bpf_ctx... - I like how hid_bpf_allocate_context() works with the same struct that can be later used with the same functions hid_bpf_input_event() or such (arguably I could return the struct hid_device directly)
I'll try to give it more thoughts :)
Overall it looks great. hid_id did the trick :)
Thanks!
I agree, relying on struct_ops allowed to do a heavy cleanup in my code, and TBH, even if I had only one callback, I think the gain is clear, because it's much straightforward and you can also authorize some fine grain write on your own structs (like changing the name of the hid_device, or its flags, which is not part of this series, but which will likely come later).
Cheers, Benjamin
On Wed, May 29, 2024 at 12:38 AM Benjamin Tissoires bentiss@kernel.org wrote:
Take a look at include/linux/bpf_mprog.h I suspect it might be useful here too.
From the quick look of it this is interesting, but for plain struct bpf_prog, right?
So I would have to adapt this include for struct_ops?
yeah. It needs work to be adapted to work with struct-ops. I mentioned it mainly from uapi perspective. BPF_F_BEFORE, BPF_F_AFTER, BPF_F_REPLACE. Would be good to keep things consistent.
@@ -112,6 +113,63 @@ struct hid_ops {
extern struct hid_ops *hid_ops;
+/**
- struct hid_bpf_ops - A BPF struct_ops of callbacks allowing to attach HID-BPF
programs to a HID device
- @hid_id: the HID uniq ID to attach to. This is writeable before ``load()``, and
cannot be changed after
- @flags: &enum hid_bpf_attach_flags to assign flags before ``load()``.
Writeable only before ``load()``- */
+struct hid_bpf_ops {
/* hid_id needs to stay first so we can easily change it* from userspace.*/hmm. patch 5 just does:
skel->struct_ops.mouse_invert->hid_id = hid_id;I don't see a reason why it needs to be first.
See the selftests (and my external loader, udev-hid-bpf):
map = bpf_object__find_map_by_name(*self->skel->skeleton->obj, programs[i].name + 4); ASSERT_OK_PTR(map) TH_LOG("can not find struct_ops by name '%s'", programs[i].name + 4); /* hid_id is the first field of struct hid_bpf_ops */ ops_hid_id = bpf_map__initial_value(map, NULL); ASSERT_OK_PTR(ops_hid_id) TH_LOG("unable to retrieve struct_ops data"); *ops_hid_id = self->hid_id;Basically, I want to have to deal with .bpf.o and not the skeletons for the generic case. I want to be able to drop a file in /lib/firmware/hid and have udev-hid-bpf load it without having to recompile udev-hid-bpf.
and with additional restriction of only one struct-ops prog per elf file, right? Otherwise multiple hid_bpf_ops will be in the same elf section and the same map.
I couldn't seem to be able to access the struct_ops BTF information from libbpf, so I decided to have hid_id and flags first and consider this to be ABI while I figure out how to get to the real offsets :)
I see. I guess it's ok for now.
Hi Benjamin,
kernel test robot noticed the following build warnings:
[auto build test WARNING on 70ec81c2e2b4005465ad0d042e90b36087c36104]
url: https://github.com/intel-lab-lkp/linux/commits/Benjamin-Tissoires/HID-rename... base: 70ec81c2e2b4005465ad0d042e90b36087c36104 patch link: https://lore.kernel.org/r/20240528-hid_bpf_struct_ops-v1-3-8c6663df27d8%40ke... patch subject: [PATCH HID 03/13] HID: bpf: implement HID-BPF through bpf_struct_ops config: i386-buildonly-randconfig-002-20240531 (https://download.01.org/0day-ci/archive/20240531/202405312035.U1rZN04z-lkp@i...) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240531/202405312035.U1rZN04z-lkp@i...)
If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot lkp@intel.com | Closes: https://lore.kernel.org/oe-kbuild-all/202405312035.U1rZN04z-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from include/linux/bpf_verifier.h:7:0, from drivers/hid/bpf/hid_bpf_struct_ops.c:10: drivers/hid/bpf/hid_bpf_struct_ops.c: In function 'hid_bpf_struct_ops_init':
include/linux/bpf.h:1844:50: warning: statement with no effect [-Wunused-value]
#define register_bpf_struct_ops(st_ops, type) ({ (void *)(st_ops); 0; }) ^~~~~~~~~~~~~~~~ drivers/hid/bpf/hid_bpf_struct_ops.c:244:9: note: in expansion of macro 'register_bpf_struct_ops' return register_bpf_struct_ops(&bpf_hid_bpf_ops, hid_bpf_ops); ^~~~~~~~~~~~~~~~~~~~~~~
vim +1844 include/linux/bpf.h
c196906d50e360d Hou Tao 2021-10-25 1834 c196906d50e360d Hou Tao 2021-10-25 1835 int bpf_struct_ops_test_run(struct bpf_prog *prog, const union bpf_attr *kattr, c196906d50e360d Hou Tao 2021-10-25 1836 union bpf_attr __user *uattr); c196906d50e360d Hou Tao 2021-10-25 1837 #endif f6be98d19985411 Kui-Feng Lee 2024-01-19 1838 int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc, f6be98d19985411 Kui-Feng Lee 2024-01-19 1839 struct btf *btf, f6be98d19985411 Kui-Feng Lee 2024-01-19 1840 struct bpf_verifier_log *log); 1338b93346587a2 Kui-Feng Lee 2024-01-19 1841 void bpf_map_struct_ops_info_fill(struct bpf_map_info *info, struct bpf_map *map); 1611603537a4b88 Kui-Feng Lee 2024-02-08 1842 void bpf_struct_ops_desc_release(struct bpf_struct_ops_desc *st_ops_desc); 27ae7997a66174c Martin KaFai Lau 2020-01-08 1843 #else f6be98d19985411 Kui-Feng Lee 2024-01-19 @1844 #define register_bpf_struct_ops(st_ops, type) ({ (void *)(st_ops); 0; }) 85d33df357b6346 Martin KaFai Lau 2020-01-08 1845 static inline bool bpf_try_module_get(const void *data, struct module *owner) 85d33df357b6346 Martin KaFai Lau 2020-01-08 1846 { 85d33df357b6346 Martin KaFai Lau 2020-01-08 1847 return try_module_get(owner); 85d33df357b6346 Martin KaFai Lau 2020-01-08 1848 } 85d33df357b6346 Martin KaFai Lau 2020-01-08 1849 static inline void bpf_module_put(const void *data, struct module *owner) 85d33df357b6346 Martin KaFai Lau 2020-01-08 1850 { 85d33df357b6346 Martin KaFai Lau 2020-01-08 1851 module_put(owner); 85d33df357b6346 Martin KaFai Lau 2020-01-08 1852 } 85d33df357b6346 Martin KaFai Lau 2020-01-08 1853 static inline int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, 85d33df357b6346 Martin KaFai Lau 2020-01-08 1854 void *key, 85d33df357b6346 Martin KaFai Lau 2020-01-08 1855 void *value) 85d33df357b6346 Martin KaFai Lau 2020-01-08 1856 { 85d33df357b6346 Martin KaFai Lau 2020-01-08 1857 return -EINVAL; 85d33df357b6346 Martin KaFai Lau 2020-01-08 1858 } 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1859 static inline int bpf_struct_ops_link_create(union bpf_attr *attr) 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1860 { 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1861 return -EOPNOTSUPP; 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1862 } 1338b93346587a2 Kui-Feng Lee 2024-01-19 1863 static inline void bpf_map_struct_ops_info_fill(struct bpf_map_info *info, struct bpf_map *map) 1338b93346587a2 Kui-Feng Lee 2024-01-19 1864 { 1338b93346587a2 Kui-Feng Lee 2024-01-19 1865 } 68b04864ca425d1 Kui-Feng Lee 2023-03-22 1866
We drop the need for the attach() bpf syscall, but we need to set up the hid_id field before calling __load().
The .bpf.c part is mechanical: we create one struct_ops per HID-BPF program, as all the tests are for one program at a time.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- tools/testing/selftests/hid/hid_bpf.c | 59 +++++++++++++------------ tools/testing/selftests/hid/progs/hid.c | 76 +++++++++++++++++++++++---------- 2 files changed, 85 insertions(+), 50 deletions(-)
diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c index f825623e3edc..967dfe6b58cb 100644 --- a/tools/testing/selftests/hid/hid_bpf.c +++ b/tools/testing/selftests/hid/hid_bpf.c @@ -460,7 +460,7 @@ FIXTURE(hid_bpf) { int hid_id; pthread_t tid; struct hid *skel; - int hid_links[3]; /* max number of programs loaded in a single test */ + struct bpf_link *hid_links[3]; /* max number of programs loaded in a single test */ }; static void detach_bpf(FIXTURE_DATA(hid_bpf) * self) { @@ -472,7 +472,7 @@ static void detach_bpf(FIXTURE_DATA(hid_bpf) * self)
for (i = 0; i < ARRAY_SIZE(self->hid_links); i++) { if (self->hid_links[i]) - close(self->hid_links[i]); + bpf_link__destroy(self->hid_links[i]); }
hid__destroy(self->skel); @@ -527,14 +527,7 @@ static void load_programs(const struct test_program programs[], FIXTURE_DATA(hid_bpf) * self, const FIXTURE_VARIANT(hid_bpf) * variant) { - int attach_fd, err = -EINVAL; - struct attach_prog_args args = { - .retval = -1, - }; - DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr, - .ctx_in = &args, - .ctx_size_in = sizeof(args), - ); + int err = -EINVAL;
ASSERT_LE(progs_count, ARRAY_SIZE(self->hid_links)) TH_LOG("too many programs are to be loaded"); @@ -545,35 +538,41 @@ static void load_programs(const struct test_program programs[],
for (int i = 0; i < progs_count; i++) { struct bpf_program *prog; + struct bpf_map *map; + int *ops_hid_id;
prog = bpf_object__find_program_by_name(*self->skel->skeleton->obj, programs[i].name); ASSERT_OK_PTR(prog) TH_LOG("can not find program by name '%s'", programs[i].name);
bpf_program__set_autoload(prog, true); + + map = bpf_object__find_map_by_name(*self->skel->skeleton->obj, + programs[i].name + 4); + ASSERT_OK_PTR(map) TH_LOG("can not find struct_ops by name '%s'", + programs[i].name + 4); + + /* hid_id is the first field of struct hid_bpf_ops */ + ops_hid_id = bpf_map__initial_value(map, NULL); + ASSERT_OK_PTR(ops_hid_id) TH_LOG("unable to retrieve struct_ops data"); + + *ops_hid_id = self->hid_id; }
err = hid__load(self->skel); ASSERT_OK(err) TH_LOG("hid_skel_load failed: %d", err);
- attach_fd = bpf_program__fd(self->skel->progs.attach_prog); - ASSERT_GE(attach_fd, 0) TH_LOG("locate attach_prog: %d", attach_fd); - for (int i = 0; i < progs_count; i++) { - struct bpf_program *prog; + struct bpf_map *map;
- prog = bpf_object__find_program_by_name(*self->skel->skeleton->obj, - programs[i].name); - ASSERT_OK_PTR(prog) TH_LOG("can not find program by name '%s'", programs[i].name); - - args.prog_fd = bpf_program__fd(prog); - args.hid = self->hid_id; - args.insert_head = programs[i].insert_head; - err = bpf_prog_test_run_opts(attach_fd, &tattr); - ASSERT_GE(args.retval, 0) - TH_LOG("attach_hid(%s): %d", programs[i].name, args.retval); + map = bpf_object__find_map_by_name(*self->skel->skeleton->obj, + programs[i].name + 4); + ASSERT_OK_PTR(map) TH_LOG("can not find struct_ops by name '%s'", + programs[i].name + 4);
- self->hid_links[i] = args.retval; + self->hid_links[i] = bpf_map__attach_struct_ops(map); + ASSERT_OK_PTR(self->hid_links[i]) TH_LOG("failed to attach struct ops '%s'", + programs[i].name + 4); }
self->hidraw_fd = open_hidraw(self->dev_id); @@ -648,13 +647,17 @@ TEST_F(hid_bpf, test_attach_detach) { .name = "hid_first_event" }, { .name = "hid_second_event" }, }; + struct bpf_link *link; __u8 buf[10] = {0}; - int err, link; + int err, link_fd;
LOAD_PROGRAMS(progs);
link = self->hid_links[0]; - ASSERT_GT(link, 0) TH_LOG("HID-BPF link not created"); + ASSERT_OK_PTR(link) TH_LOG("HID-BPF link not created"); + + link_fd = bpf_link__fd(link); + ASSERT_GE(link_fd, 0) TH_LOG("HID-BPF link FD not valid");
/* inject one event */ buf[0] = 1; @@ -673,7 +676,7 @@ TEST_F(hid_bpf, test_attach_detach)
/* pin the first program and immediately unpin it */ #define PIN_PATH "/sys/fs/bpf/hid_first_event" - err = bpf_obj_pin(link, PIN_PATH); + err = bpf_obj_pin(link_fd, PIN_PATH); ASSERT_OK(err) TH_LOG("error while calling bpf_obj_pin"); remove(PIN_PATH); #undef PIN_PATH diff --git a/tools/testing/selftests/hid/progs/hid.c b/tools/testing/selftests/hid/progs/hid.c index f67d35def142..9adace26e8aa 100644 --- a/tools/testing/selftests/hid/progs/hid.c +++ b/tools/testing/selftests/hid/progs/hid.c @@ -14,8 +14,8 @@ struct attach_prog_args { __u64 callback_check = 52; __u64 callback2_check = 52;
-SEC("?fmod_ret/hid_bpf_device_event") -int BPF_PROG(hid_first_event, struct hid_bpf_ctx *hid_ctx) +SEC("?struct_ops/hid_device_event") +int BPF_PROG(hid_first_event, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) { __u8 *rw_data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 3 /* size */);
@@ -29,8 +29,14 @@ int BPF_PROG(hid_first_event, struct hid_bpf_ctx *hid_ctx) return hid_ctx->size; }
-SEC("?fmod_ret/hid_bpf_device_event") -int BPF_PROG(hid_second_event, struct hid_bpf_ctx *hid_ctx) +SEC(".struct_ops.link") +struct hid_bpf_ops first_event = { + .hid_device_event = (void *)hid_first_event, + .hid_id = 2, +}; + +SEC("?struct_ops/hid_device_event") +int BPF_PROG(hid_second_event, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) { __u8 *rw_data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4 /* size */);
@@ -42,8 +48,13 @@ int BPF_PROG(hid_second_event, struct hid_bpf_ctx *hid_ctx) return hid_ctx->size; }
-SEC("?fmod_ret/hid_bpf_device_event") -int BPF_PROG(hid_change_report_id, struct hid_bpf_ctx *hid_ctx) +SEC(".struct_ops.link") +struct hid_bpf_ops second_event = { + .hid_device_event = (void *)hid_second_event, +}; + +SEC("?struct_ops/hid_device_event") +int BPF_PROG(hid_change_report_id, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) { __u8 *rw_data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 3 /* size */);
@@ -55,15 +66,10 @@ int BPF_PROG(hid_change_report_id, struct hid_bpf_ctx *hid_ctx) return 9; }
-SEC("syscall") -int attach_prog(struct attach_prog_args *ctx) -{ - ctx->retval = hid_bpf_attach_prog(ctx->hid, - ctx->prog_fd, - ctx->insert_head ? HID_BPF_FLAG_INSERT_HEAD : - HID_BPF_FLAG_NONE); - return 0; -} +SEC(".struct_ops.link") +struct hid_bpf_ops change_report_id = { + .hid_device_event = (void *)hid_change_report_id, +};
struct hid_hw_request_syscall_args { /* data needs to come at offset 0 so we can use it in calls */ @@ -181,7 +187,12 @@ static const __u8 rdesc[] = { 0xc0, /* END_COLLECTION */ };
-SEC("?fmod_ret/hid_bpf_rdesc_fixup") +/* + * the following program is marked as sleepable (struct_ops.s). + * This is not strictly mandatory but is a nice test for + * sleepable struct_ops + */ +SEC("?struct_ops.s/hid_rdesc_fixup") int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hid_ctx) { __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4096 /* size */); @@ -200,8 +211,13 @@ int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hid_ctx) return sizeof(rdesc) + 73; }
-SEC("?fmod_ret/hid_bpf_device_event") -int BPF_PROG(hid_test_insert1, struct hid_bpf_ctx *hid_ctx) +SEC(".struct_ops.link") +struct hid_bpf_ops rdesc_fixup = { + .hid_rdesc_fixup = (void *)hid_rdesc_fixup, +}; + +SEC("?struct_ops/hid_device_event") +int BPF_PROG(hid_test_insert1, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) { __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4 /* size */);
@@ -217,8 +233,14 @@ int BPF_PROG(hid_test_insert1, struct hid_bpf_ctx *hid_ctx) return 0; }
-SEC("?fmod_ret/hid_bpf_device_event") -int BPF_PROG(hid_test_insert2, struct hid_bpf_ctx *hid_ctx) +SEC(".struct_ops.link") +struct hid_bpf_ops test_insert1 = { + .hid_device_event = (void *)hid_test_insert1, + .flags = HID_BPF_FLAG_INSERT_HEAD, +}; + +SEC("?struct_ops/hid_device_event") +int BPF_PROG(hid_test_insert2, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) { __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4 /* size */);
@@ -234,8 +256,13 @@ int BPF_PROG(hid_test_insert2, struct hid_bpf_ctx *hid_ctx) return 0; }
-SEC("?fmod_ret/hid_bpf_device_event") -int BPF_PROG(hid_test_insert3, struct hid_bpf_ctx *hid_ctx) +SEC(".struct_ops.link") +struct hid_bpf_ops test_insert2 = { + .hid_device_event = (void *)hid_test_insert2, +}; + +SEC("?struct_ops/hid_device_event") +int BPF_PROG(hid_test_insert3, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) { __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4 /* size */);
@@ -250,3 +277,8 @@ int BPF_PROG(hid_test_insert3, struct hid_bpf_ctx *hid_ctx)
return 0; } + +SEC(".struct_ops.link") +struct hid_bpf_ops test_insert3 = { + .hid_device_event = (void *)hid_test_insert3, +};
hid_mouse is currently failing with bpf_printk() not available in struct_ops program type.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- samples/hid/Makefile | 5 ++-- samples/hid/hid_bpf_attach.bpf.c | 18 ------------- samples/hid/hid_bpf_attach.h | 14 ---------- samples/hid/hid_mouse.bpf.c | 26 +++++++++++++++---- samples/hid/hid_mouse.c | 39 ++++++++-------------------- samples/hid/hid_surface_dial.bpf.c | 10 +++++-- samples/hid/hid_surface_dial.c | 53 +++++++++++--------------------------- 7 files changed, 57 insertions(+), 108 deletions(-)
diff --git a/samples/hid/Makefile b/samples/hid/Makefile index c128ccd49974..8ea59e9631a3 100644 --- a/samples/hid/Makefile +++ b/samples/hid/Makefile @@ -16,7 +16,6 @@ LIBBPF_DESTDIR = $(LIBBPF_OUTPUT) LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a
-EXTRA_HEADERS := hid_bpf_attach.h EXTRA_BPF_HEADERS := hid_bpf_helpers.h
hid_mouse-objs := hid_mouse.o @@ -207,8 +206,8 @@ $(obj)/%.bpf.o: $(src)/%.bpf.c $(EXTRA_BPF_HEADERS_SRC) $(obj)/vmlinux.h LINKED_SKELS := hid_mouse.skel.h hid_surface_dial.skel.h clean-files += $(LINKED_SKELS)
-hid_mouse.skel.h-deps := hid_mouse.bpf.o hid_bpf_attach.bpf.o -hid_surface_dial.skel.h-deps := hid_surface_dial.bpf.o hid_bpf_attach.bpf.o +hid_mouse.skel.h-deps := hid_mouse.bpf.o +hid_surface_dial.skel.h-deps := hid_surface_dial.bpf.o
LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))
diff --git a/samples/hid/hid_bpf_attach.bpf.c b/samples/hid/hid_bpf_attach.bpf.c deleted file mode 100644 index d4dce4ea7c6e..000000000000 --- a/samples/hid/hid_bpf_attach.bpf.c +++ /dev/null @@ -1,18 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* Copyright (c) 2022 Benjamin Tissoires - */ - -#include "vmlinux.h" -#include <bpf/bpf_helpers.h> -#include <bpf/bpf_tracing.h> -#include "hid_bpf_attach.h" -#include "hid_bpf_helpers.h" - -SEC("syscall") -int attach_prog(struct attach_prog_args *ctx) -{ - ctx->retval = hid_bpf_attach_prog(ctx->hid, - ctx->prog_fd, - 0); - return 0; -} diff --git a/samples/hid/hid_bpf_attach.h b/samples/hid/hid_bpf_attach.h deleted file mode 100644 index 35bb28b49264..000000000000 --- a/samples/hid/hid_bpf_attach.h +++ /dev/null @@ -1,14 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0-only */ -/* Copyright (c) 2022 Benjamin Tissoires - */ - -#ifndef __HID_BPF_ATTACH_H -#define __HID_BPF_ATTACH_H - -struct attach_prog_args { - int prog_fd; - unsigned int hid; - int retval; -}; - -#endif /* __HID_BPF_ATTACH_H */ diff --git a/samples/hid/hid_mouse.bpf.c b/samples/hid/hid_mouse.bpf.c index 7c8b453ccb16..bd901fa855c9 100644 --- a/samples/hid/hid_mouse.bpf.c +++ b/samples/hid/hid_mouse.bpf.c @@ -5,8 +5,7 @@ #include <bpf/bpf_tracing.h> #include "hid_bpf_helpers.h"
-SEC("fmod_ret/hid_bpf_device_event") -int BPF_PROG(hid_y_event, struct hid_bpf_ctx *hctx) +static int hid_y_event(struct hid_bpf_ctx *hctx) { s16 y; __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */); @@ -51,8 +50,7 @@ int BPF_PROG(hid_y_event, struct hid_bpf_ctx *hctx) return 0; }
-SEC("fmod_ret/hid_bpf_device_event") -int BPF_PROG(hid_x_event, struct hid_bpf_ctx *hctx) +static int hid_x_event(struct hid_bpf_ctx *hctx) { s16 x; __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */); @@ -69,7 +67,19 @@ int BPF_PROG(hid_x_event, struct hid_bpf_ctx *hctx) return 0; }
-SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC("struct_ops/device_event") +int BPF_PROG(hid_event, struct hid_bpf_ctx *hctx, enum hid_report_type type) +{ + int ret = hid_y_event(hctx); + + if (ret) + return ret; + + return hid_x_event(hctx); +} + + +SEC("struct_ops/rdesc_fixup") int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */); @@ -109,4 +119,10 @@ int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx) return 0; }
+SEC(".struct_ops.link") +struct hid_bpf_ops mouse_invert = { + .rdesc_fixup = (void *)hid_rdesc_fixup, + .device_event = (void *)hid_event, +}; + char _license[] SEC("license") = "GPL"; diff --git a/samples/hid/hid_mouse.c b/samples/hid/hid_mouse.c index 018f1185f203..4b80d4e4c154 100644 --- a/samples/hid/hid_mouse.c +++ b/samples/hid/hid_mouse.c @@ -29,7 +29,6 @@ #include <bpf/libbpf.h>
#include "hid_mouse.skel.h" -#include "hid_bpf_attach.h"
static bool running = true;
@@ -76,18 +75,11 @@ static int get_hid_id(const char *path) int main(int argc, char **argv) { struct hid_mouse *skel; - struct bpf_program *prog; + struct bpf_link *link; int err; const char *optstr = ""; const char *sysfs_path; - int opt, hid_id, attach_fd; - struct attach_prog_args args = { - .retval = -1, - }; - DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr, - .ctx_in = &args, - .ctx_size_in = sizeof(args), - ); + int opt, hid_id;
while ((opt = getopt(argc, argv, optstr)) != -1) { switch (opt) { @@ -108,7 +100,7 @@ int main(int argc, char **argv) return 1; }
- skel = hid_mouse__open_and_load(); + skel = hid_mouse__open(); if (!skel) { fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__); return -1; @@ -120,27 +112,18 @@ int main(int argc, char **argv) fprintf(stderr, "can not open HID device: %m\n"); return 1; } - args.hid = hid_id; + skel->struct_ops.mouse_invert->hid_id = hid_id;
- attach_fd = bpf_program__fd(skel->progs.attach_prog); - if (attach_fd < 0) { - fprintf(stderr, "can't locate attach prog: %m\n"); + err = hid_mouse__load(skel); + if (err < 0) { + fprintf(stderr, "can not load HID-BPF program: %m\n"); return 1; }
- bpf_object__for_each_program(prog, *skel->skeleton->obj) { - /* ignore syscalls */ - if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING) - continue; - - args.retval = -1; - args.prog_fd = bpf_program__fd(prog); - err = bpf_prog_test_run_opts(attach_fd, &tattr); - if (err) { - fprintf(stderr, "can't attach prog to hid device %d: %m (err: %d)\n", - hid_id, err); - return 1; - } + link = bpf_map__attach_struct_ops(skel->maps.mouse_invert); + if (!link) { + fprintf(stderr, "can not attach HID-BPF program: %m\n"); + return 1; }
signal(SIGINT, int_exit); diff --git a/samples/hid/hid_surface_dial.bpf.c b/samples/hid/hid_surface_dial.bpf.c index 1f80478c0918..d8d0fb07391f 100644 --- a/samples/hid/hid_surface_dial.bpf.c +++ b/samples/hid/hid_surface_dial.bpf.c @@ -10,7 +10,7 @@ #define HID_UP_BUTTON 0x0009 #define HID_GD_WHEEL 0x0038
-SEC("fmod_ret/hid_bpf_device_event") +SEC("struct_ops/device_event") int BPF_PROG(hid_event, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */); @@ -101,7 +101,7 @@ int set_haptic(struct haptic_syscall_args *args) }
/* Convert REL_DIAL into REL_WHEEL */ -SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC("struct_ops/rdesc_fixup") int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */); @@ -130,5 +130,11 @@ int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx) return 0; }
+SEC(".struct_ops.link") +struct hid_bpf_ops surface_dial = { + .rdesc_fixup = (void *)hid_rdesc_fixup, + .device_event = (void *)hid_event, +}; + char _license[] SEC("license") = "GPL"; u32 _version SEC("version") = 1; diff --git a/samples/hid/hid_surface_dial.c b/samples/hid/hid_surface_dial.c index 4bc97373a708..9dd363845a85 100644 --- a/samples/hid/hid_surface_dial.c +++ b/samples/hid/hid_surface_dial.c @@ -31,7 +31,6 @@ #include <bpf/libbpf.h>
#include "hid_surface_dial.skel.h" -#include "hid_bpf_attach.h"
static bool running = true;
@@ -86,34 +85,6 @@ static int get_hid_id(const char *path) return (int)strtol(str_id, NULL, 16); }
-static int attach_prog(struct hid_surface_dial *skel, struct bpf_program *prog, int hid_id) -{ - struct attach_prog_args args = { - .hid = hid_id, - .retval = -1, - }; - int attach_fd, err; - DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr, - .ctx_in = &args, - .ctx_size_in = sizeof(args), - ); - - attach_fd = bpf_program__fd(skel->progs.attach_prog); - if (attach_fd < 0) { - fprintf(stderr, "can't locate attach prog: %m\n"); - return 1; - } - - args.prog_fd = bpf_program__fd(prog); - err = bpf_prog_test_run_opts(attach_fd, &tattr); - if (err) { - fprintf(stderr, "can't attach prog to hid device %d: %m (err: %d)\n", - hid_id, err); - return 1; - } - return 0; -} - static int set_haptic(struct hid_surface_dial *skel, int hid_id) { struct haptic_syscall_args args = { @@ -144,10 +115,10 @@ static int set_haptic(struct hid_surface_dial *skel, int hid_id) int main(int argc, char **argv) { struct hid_surface_dial *skel; - struct bpf_program *prog; const char *optstr = "r:"; + struct bpf_link *link; const char *sysfs_path; - int opt, hid_id, resolution = 72; + int err, opt, hid_id, resolution = 72;
while ((opt = getopt(argc, argv, optstr)) != -1) { switch (opt) { @@ -189,7 +160,7 @@ int main(int argc, char **argv) return 1; }
- skel = hid_surface_dial__open_and_load(); + skel = hid_surface_dial__open(); if (!skel) { fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__); return -1; @@ -201,15 +172,21 @@ int main(int argc, char **argv) return 1; }
+ skel->struct_ops.surface_dial->hid_id = hid_id; + + err = hid_surface_dial__load(skel); + if (err < 0) { + fprintf(stderr, "can not load HID-BPF program: %m\n"); + return 1; + } + skel->data->resolution = resolution; skel->data->physical = (int)(resolution / 72);
- bpf_object__for_each_program(prog, *skel->skeleton->obj) { - /* ignore syscalls */ - if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING) - continue; - - attach_prog(skel, prog, hid_id); + link = bpf_map__attach_struct_ops(skel->maps.surface_dial); + if (!link) { + fprintf(stderr, "can not attach HID-BPF program: %m\n"); + return 1; }
signal(SIGINT, int_exit);
We are going to switch over struct_ops, so instead of having to manually replace all fields one by one, let's have a common place to change it.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c | 4 ++-- drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c | 2 +- drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c | 4 ++-- drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c | 2 +- drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c | 2 +- drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c | 2 +- drivers/hid/bpf/progs/XPPen__Artist24.bpf.c | 4 ++-- drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c | 6 +++--- drivers/hid/bpf/progs/hid_bpf.h | 3 +++ 9 files changed, 16 insertions(+), 13 deletions(-)
diff --git a/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c b/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c index dc26a7677d36..2c2c1637ade8 100644 --- a/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c +++ b/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c @@ -133,7 +133,7 @@ HID_BPF_CONFIG( * integer. We thus divide it by 30 to match what other joysticks are * doing */ -SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC(HID_BPF_RDESC_FIXUP) int BPF_PROG(hid_fix_rdesc_raptor_mach_2, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, HID_MAX_DESCRIPTOR_SIZE /* size */); @@ -152,7 +152,7 @@ int BPF_PROG(hid_fix_rdesc_raptor_mach_2, struct hid_bpf_ctx *hctx) * divide it by 30. * Byte 34 is always null, so it is ignored. */ -SEC("fmod_ret/hid_bpf_device_event") +SEC(HID_BPF_DEVICE_EVENT) int BPF_PROG(raptor_mach_2_fix_hat_switch, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 64 /* size */); diff --git a/drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c b/drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c index 3d14bbb6f276..17fc55f6f02c 100644 --- a/drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c +++ b/drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c @@ -30,7 +30,7 @@ HID_BPF_CONFIG( * pointer. */
-SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC(HID_BPF_RDESC_FIXUP) int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */); diff --git a/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c b/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c index ff759f2276f9..24b8a5aa05f3 100644 --- a/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c +++ b/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c @@ -191,7 +191,7 @@ static const __u8 fixed_rdesc[] = { 0xc0, // End Collection 327 };
-SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC(HID_BPF_RDESC_FIXUP) int BPF_PROG(hid_fix_rdesc_huion_kamvas_pro_19, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, HID_MAX_DESCRIPTOR_SIZE /* size */); @@ -215,7 +215,7 @@ int BPF_PROG(hid_fix_rdesc_huion_kamvas_pro_19, struct hid_bpf_ctx *hctx) * - if there was this out-of-proximity event, we are entering * eraser mode, and we will until the next out-of-proximity. */ -SEC("fmod_ret/hid_bpf_device_event") +SEC(HID_BPF_DEVICE_EVENT) int BPF_PROG(kamvas_pro_19_fix_3rd_button, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */); diff --git a/drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c b/drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c index 225cbefdbf0e..bee37872ee8c 100644 --- a/drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c +++ b/drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c @@ -21,7 +21,7 @@ HID_BPF_CONFIG( * We just fix the report descriptor to enable those missing 7 buttons. */
-SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC(HID_BPF_RDESC_FIXUP) int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx) { const u8 offsets[] = {84, 112, 140}; diff --git a/drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c b/drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c index c04abecab8ee..f9ad33f4a373 100644 --- a/drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c +++ b/drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c @@ -93,7 +93,7 @@ _Static_assert(sizeof(rdesc_assign_selection) == sizeof(fixed_rdesc_assign_selec _Static_assert(sizeof(rdesc_assign_selection) + OFFSET_ASSIGN_SELECTION < ORIGINAL_RDESC_SIZE, "Rdesc at given offset is too big");
-SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC(HID_BPF_RDESC_FIXUP) int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */); diff --git a/drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c b/drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c index dc05aa48faa7..39d77c5e9172 100644 --- a/drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c +++ b/drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c @@ -101,7 +101,7 @@ static inline __u8 *get_u8(__u8 *data, unsigned int offset) return (__u8 *)get_bits(data, offset); }
-SEC("fmod_ret/hid_bpf_device_event") +SEC(HID_BPF_DEVICE_EVENT) int BPF_PROG(artpen_pressure_interpolate, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, PEN_REPORT_LEN /* size */); diff --git a/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c b/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c index e1be6a12bb75..c938808bd589 100644 --- a/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c +++ b/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c @@ -91,7 +91,7 @@ static const __u8 fixed_rdesc[] = {
#define U16(index) (data[index] | (data[index + 1] << 8))
-SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC(HID_BPF_RDESC_FIXUP) int BPF_PROG(hid_fix_rdesc_xppen_artist24, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */); @@ -152,7 +152,7 @@ static __u8 prev_state = 0; * E: TipSwitch InRange * */ -SEC("fmod_ret/hid_bpf_device_event") +SEC(HID_BPF_DEVICE_EVENT) int BPF_PROG(xppen_24_fix_eraser, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */); diff --git a/drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c b/drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c index 65ef10036126..77ef8b95d52e 100644 --- a/drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c +++ b/drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c @@ -82,7 +82,7 @@ static const __u8 fixed_rdesc[] = { 0xc0, // End Collection 112 };
-SEC("fmod_ret/hid_bpf_rdesc_fixup") +SEC(HID_BPF_RDESC_FIXUP) int BPF_PROG(hid_fix_rdesc_xppen_artistpro16gen2, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */); @@ -105,7 +105,7 @@ int BPF_PROG(hid_fix_rdesc_xppen_artistpro16gen2, struct hid_bpf_ctx *hctx) return sizeof(fixed_rdesc); }
-SEC("fmod_ret/hid_bpf_device_event") +SEC(HID_BPF_DEVICE_EVENT) int BPF_PROG(xppen_16_fix_eraser, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */); @@ -207,7 +207,7 @@ static void compensate_coordinates_by_tilt(__u8 *data, const __u8 idx, data[idx+1] = coords >> 8; }
-SEC("fmod_ret/hid_bpf_device_event") +SEC(HID_BPF_DEVICE_EVENT) int BPF_PROG(xppen_16_fix_angle_offset, struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */); diff --git a/drivers/hid/bpf/progs/hid_bpf.h b/drivers/hid/bpf/progs/hid_bpf.h index 7ee371cac2e1..1970faf84310 100644 --- a/drivers/hid/bpf/progs/hid_bpf.h +++ b/drivers/hid/bpf/progs/hid_bpf.h @@ -5,6 +5,9 @@ #ifndef ____HID_BPF__H #define ____HID_BPF__H
+#define HID_BPF_DEVICE_EVENT "fmod_ret/hid_bpf_device_event" +#define HID_BPF_RDESC_FIXUP "fmod_ret/hid_bpf_rdesc_fixup" + struct hid_bpf_probe_args { unsigned int hid; unsigned int rdesc_size;
Very mechanical: - Change HID_BPF_DEVICE_EVENT and HID_BPF_RDESC_FIXUP #defines - add a matching SEC(".struct_ops.link") - in ArtistPro16Gen2 make the 2 functions static and have a new one calling them
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c | 5 +++++ drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c | 4 ++++ drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c | 5 +++++ .../hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c | 4 ++++ .../hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c | 4 ++++ drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c | 4 ++++ drivers/hid/bpf/progs/XPPen__Artist24.bpf.c | 5 +++++ drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c | 22 ++++++++++++++++++---- drivers/hid/bpf/progs/hid_bpf.h | 6 ++++-- 9 files changed, 53 insertions(+), 6 deletions(-)
diff --git a/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c b/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c index 2c2c1637ade8..caec91391d32 100644 --- a/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c +++ b/drivers/hid/bpf/progs/FR-TEC__Raptor-Mach-2.bpf.c @@ -168,6 +168,11 @@ int BPF_PROG(raptor_mach_2_fix_hat_switch, struct hid_bpf_ctx *hctx) return 0; }
+HID_BPF_OPS(raptor_mach_2) = { + .hid_rdesc_fixup = (void *)hid_fix_rdesc_raptor_mach_2, + .hid_device_event = (void *)raptor_mach_2_fix_hat_switch, +}; + SEC("syscall") int probe(struct hid_bpf_probe_args *ctx) { diff --git a/drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c b/drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c index 17fc55f6f02c..c2413fa80543 100644 --- a/drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c +++ b/drivers/hid/bpf/progs/HP__Elite-Presenter.bpf.c @@ -45,6 +45,10 @@ int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx) return 0; }
+HID_BPF_OPS(hp_elite_presenter) = { + .hid_rdesc_fixup = (void *)hid_fix_rdesc, +}; + SEC("syscall") int probe(struct hid_bpf_probe_args *ctx) { diff --git a/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c b/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c index 24b8a5aa05f3..a4a4f324aedd 100644 --- a/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c +++ b/drivers/hid/bpf/progs/Huion__Kamvas-Pro-19.bpf.c @@ -255,6 +255,11 @@ int BPF_PROG(kamvas_pro_19_fix_3rd_button, struct hid_bpf_ctx *hctx) return 0; }
+HID_BPF_OPS(huion_Kamvas_pro_19) = { + .hid_rdesc_fixup = (void *)hid_fix_rdesc_huion_kamvas_pro_19, + .hid_device_event = (void *)kamvas_pro_19_fix_3rd_button, +}; + SEC("syscall") int probe(struct hid_bpf_probe_args *ctx) { diff --git a/drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c b/drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c index bee37872ee8c..82f1950445dd 100644 --- a/drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c +++ b/drivers/hid/bpf/progs/IOGEAR__Kaliber-MMOmentum.bpf.c @@ -45,6 +45,10 @@ int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx) return 0; }
+HID_BPF_OPS(iogear_kaliber_momentum) = { + .hid_rdesc_fixup = (void *)hid_fix_rdesc, +}; + SEC("syscall") int probe(struct hid_bpf_probe_args *ctx) { diff --git a/drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c b/drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c index f9ad33f4a373..70b16edfb59a 100644 --- a/drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c +++ b/drivers/hid/bpf/progs/Microsoft__XBox-Elite-2.bpf.c @@ -114,6 +114,10 @@ int BPF_PROG(hid_fix_rdesc, struct hid_bpf_ctx *hctx) return 0; }
+HID_BPF_OPS(xbox_elite_2) = { + .hid_rdesc_fixup = (void *)hid_fix_rdesc, +}; + SEC("syscall") int probe(struct hid_bpf_probe_args *ctx) { diff --git a/drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c b/drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c index 39d77c5e9172..2da680bc4e11 100644 --- a/drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c +++ b/drivers/hid/bpf/progs/Wacom__ArtPen.bpf.c @@ -139,6 +139,10 @@ int BPF_PROG(artpen_pressure_interpolate, struct hid_bpf_ctx *hctx) return 0; }
+HID_BPF_OPS(wacom_artpen) = { + .hid_device_event = (void *)artpen_pressure_interpolate, +}; + SEC("syscall") int probe(struct hid_bpf_probe_args *ctx) { diff --git a/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c b/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c index c938808bd589..bc0b85c38445 100644 --- a/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c +++ b/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c @@ -209,6 +209,11 @@ int BPF_PROG(xppen_24_fix_eraser, struct hid_bpf_ctx *hctx) return 0; }
+HID_BPF_OPS(xppen_artist_24) = { + .hid_rdesc_fixup = (void *)hid_fix_rdesc_xppen_artist24, + .hid_device_event = (void *)xppen_24_fix_eraser, +}; + SEC("syscall") int probe(struct hid_bpf_probe_args *ctx) { diff --git a/drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c b/drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c index 77ef8b95d52e..a669525691aa 100644 --- a/drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c +++ b/drivers/hid/bpf/progs/XPPen__ArtistPro16Gen2.bpf.c @@ -105,8 +105,7 @@ int BPF_PROG(hid_fix_rdesc_xppen_artistpro16gen2, struct hid_bpf_ctx *hctx) return sizeof(fixed_rdesc); }
-SEC(HID_BPF_DEVICE_EVENT) -int BPF_PROG(xppen_16_fix_eraser, struct hid_bpf_ctx *hctx) +static int xppen_16_fix_eraser(struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */);
@@ -207,8 +206,7 @@ static void compensate_coordinates_by_tilt(__u8 *data, const __u8 idx, data[idx+1] = coords >> 8; }
-SEC(HID_BPF_DEVICE_EVENT) -int BPF_PROG(xppen_16_fix_angle_offset, struct hid_bpf_ctx *hctx) +static int xppen_16_fix_angle_offset(struct hid_bpf_ctx *hctx) { __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */);
@@ -254,6 +252,22 @@ int BPF_PROG(xppen_16_fix_angle_offset, struct hid_bpf_ctx *hctx) return 0; }
+SEC(HID_BPF_DEVICE_EVENT) +int BPF_PROG(xppen_artist_pro_16_device_event, struct hid_bpf_ctx *hctx) +{ + int ret = xppen_16_fix_angle_offset(hctx); + + if (ret) + return ret; + + return xppen_16_fix_eraser(hctx); +} + +HID_BPF_OPS(xppen_artist_pro_16) = { + .hid_rdesc_fixup = (void *)hid_fix_rdesc_xppen_artistpro16gen2, + .hid_device_event = (void *)xppen_artist_pro_16_device_event, +}; + SEC("syscall") int probe(struct hid_bpf_probe_args *ctx) { diff --git a/drivers/hid/bpf/progs/hid_bpf.h b/drivers/hid/bpf/progs/hid_bpf.h index 1970faf84310..8c1cd9e25bc3 100644 --- a/drivers/hid/bpf/progs/hid_bpf.h +++ b/drivers/hid/bpf/progs/hid_bpf.h @@ -5,8 +5,10 @@ #ifndef ____HID_BPF__H #define ____HID_BPF__H
-#define HID_BPF_DEVICE_EVENT "fmod_ret/hid_bpf_device_event" -#define HID_BPF_RDESC_FIXUP "fmod_ret/hid_bpf_rdesc_fixup" +#define HID_BPF_DEVICE_EVENT "struct_ops/hid_device_event" +#define HID_BPF_RDESC_FIXUP "struct_ops/hid_rdesc_fixup" +#define HID_BPF_OPS(name) SEC(".struct_ops.link") \ + struct hid_bpf_ops name
struct hid_bpf_probe_args { unsigned int hid;
We can now rely on struct_ops as we cleared the users in-tree.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/Makefile | 2 +- drivers/hid/bpf/entrypoints/Makefile | 93 ---- drivers/hid/bpf/entrypoints/README | 4 - drivers/hid/bpf/entrypoints/entrypoints.bpf.c | 25 -- drivers/hid/bpf/entrypoints/entrypoints.lskel.h | 248 ----------- drivers/hid/bpf/hid_bpf_dispatch.c | 193 +------- drivers/hid/bpf/hid_bpf_dispatch.h | 8 - drivers/hid/bpf/hid_bpf_jmp_table.c | 568 ------------------------ include/linux/hid_bpf.h | 37 +- 9 files changed, 8 insertions(+), 1170 deletions(-)
diff --git a/drivers/hid/bpf/Makefile b/drivers/hid/bpf/Makefile index 1cb3f31e9335..d1f2b81788ca 100644 --- a/drivers/hid/bpf/Makefile +++ b/drivers/hid/bpf/Makefile @@ -8,4 +8,4 @@ LIBBPF_INCLUDE = $(srctree)/tools/lib obj-$(CONFIG_HID_BPF) += hid_bpf.o CFLAGS_hid_bpf_dispatch.o += -I$(LIBBPF_INCLUDE) CFLAGS_hid_bpf_jmp_table.o += -I$(LIBBPF_INCLUDE) -hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_jmp_table.o hid_bpf_struct_ops.o +hid_bpf-objs += hid_bpf_dispatch.o hid_bpf_struct_ops.o diff --git a/drivers/hid/bpf/entrypoints/Makefile b/drivers/hid/bpf/entrypoints/Makefile deleted file mode 100644 index 43b99b5575cf..000000000000 --- a/drivers/hid/bpf/entrypoints/Makefile +++ /dev/null @@ -1,93 +0,0 @@ -# SPDX-License-Identifier: GPL-2.0 -OUTPUT := .output -abs_out := $(abspath $(OUTPUT)) - -CLANG ?= clang -LLC ?= llc -LLVM_STRIP ?= llvm-strip - -TOOLS_PATH := $(abspath ../../../../tools) -BPFTOOL_SRC := $(TOOLS_PATH)/bpf/bpftool -BPFTOOL_OUTPUT := $(abs_out)/bpftool -DEFAULT_BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool -BPFTOOL ?= $(DEFAULT_BPFTOOL) - -LIBBPF_SRC := $(TOOLS_PATH)/lib/bpf -LIBBPF_OUTPUT := $(abs_out)/libbpf -LIBBPF_DESTDIR := $(LIBBPF_OUTPUT) -LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)/include -BPFOBJ := $(LIBBPF_OUTPUT)/libbpf.a - -INCLUDES := -I$(OUTPUT) -I$(LIBBPF_INCLUDE) -I$(TOOLS_PATH)/include/uapi -CFLAGS := -g -Wall - -VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \ - $(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \ - ../../../../vmlinux \ - /sys/kernel/btf/vmlinux \ - /boot/vmlinux-$(shell uname -r) -VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) -ifeq ($(VMLINUX_BTF),) -$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)") -endif - -ifeq ($(V),1) -Q = -msg = -else -Q = @ -msg = @printf ' %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))"; -MAKEFLAGS += --no-print-directory -submake_extras := feature_display=0 -endif - -.DELETE_ON_ERROR: - -.PHONY: all clean - -all: entrypoints.lskel.h - -clean: - $(call msg,CLEAN) - $(Q)rm -rf $(OUTPUT) entrypoints - -entrypoints.lskel.h: $(OUTPUT)/entrypoints.bpf.o | $(BPFTOOL) - $(call msg,GEN-SKEL,$@) - $(Q)$(BPFTOOL) gen skeleton -L $< > $@ - - -$(OUTPUT)/entrypoints.bpf.o: entrypoints.bpf.c $(OUTPUT)/vmlinux.h $(BPFOBJ) | $(OUTPUT) - $(call msg,BPF,$@) - $(Q)$(CLANG) -g -O2 --target=bpf $(INCLUDES) \ - -c $(filter %.c,$^) -o $@ && \ - $(LLVM_STRIP) -g $@ - -$(OUTPUT)/vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR) -ifeq ($(VMLINUX_H),) - $(call msg,GEN,,$@) - $(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@ -else - $(call msg,CP,,$@) - $(Q)cp "$(VMLINUX_H)" $@ -endif - -$(OUTPUT) $(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT): - $(call msg,MKDIR,$@) - $(Q)mkdir -p $@ - -$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT) - $(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) \ - OUTPUT=$(abspath $(dir $@))/ prefix= \ - DESTDIR=$(LIBBPF_DESTDIR) $(abspath $@) install_headers - -ifeq ($(CROSS_COMPILE),) -$(DEFAULT_BPFTOOL): $(BPFOBJ) | $(BPFTOOL_OUTPUT) - $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOL_SRC) \ - OUTPUT=$(BPFTOOL_OUTPUT)/ \ - LIBBPF_BOOTSTRAP_OUTPUT=$(LIBBPF_OUTPUT)/ \ - LIBBPF_BOOTSTRAP_DESTDIR=$(LIBBPF_DESTDIR)/ bootstrap -else -$(DEFAULT_BPFTOOL): | $(BPFTOOL_OUTPUT) - $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOL_SRC) \ - OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap -endif diff --git a/drivers/hid/bpf/entrypoints/README b/drivers/hid/bpf/entrypoints/README deleted file mode 100644 index 147e0d41509f..000000000000 --- a/drivers/hid/bpf/entrypoints/README +++ /dev/null @@ -1,4 +0,0 @@ -WARNING: -If you change "entrypoints.bpf.c" do "make -j" in this directory to rebuild "entrypoints.skel.h". -Make sure to have clang 10 installed. -See Documentation/bpf/bpf_devel_QA.rst diff --git a/drivers/hid/bpf/entrypoints/entrypoints.bpf.c b/drivers/hid/bpf/entrypoints/entrypoints.bpf.c deleted file mode 100644 index c22921125a1a..000000000000 --- a/drivers/hid/bpf/entrypoints/entrypoints.bpf.c +++ /dev/null @@ -1,25 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* Copyright (c) 2022 Benjamin Tissoires */ - -#include ".output/vmlinux.h" -#include <bpf/bpf_helpers.h> -#include <bpf/bpf_tracing.h> - -#define HID_BPF_MAX_PROGS 1024 - -struct { - __uint(type, BPF_MAP_TYPE_PROG_ARRAY); - __uint(max_entries, HID_BPF_MAX_PROGS); - __uint(key_size, sizeof(__u32)); - __uint(value_size, sizeof(__u32)); -} hid_jmp_table SEC(".maps"); - -SEC("fmod_ret/__hid_bpf_tail_call") -int BPF_PROG(hid_tail_call, struct hid_bpf_ctx *hctx) -{ - bpf_tail_call(ctx, &hid_jmp_table, hctx->index); - - return 0; -} - -char LICENSE[] SEC("license") = "GPL"; diff --git a/drivers/hid/bpf/entrypoints/entrypoints.lskel.h b/drivers/hid/bpf/entrypoints/entrypoints.lskel.h deleted file mode 100644 index 35618051598c..000000000000 --- a/drivers/hid/bpf/entrypoints/entrypoints.lskel.h +++ /dev/null @@ -1,248 +0,0 @@ -/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ -/* THIS FILE IS AUTOGENERATED BY BPFTOOL! */ -#ifndef __ENTRYPOINTS_BPF_SKEL_H__ -#define __ENTRYPOINTS_BPF_SKEL_H__ - -#include <bpf/skel_internal.h> - -struct entrypoints_bpf { - struct bpf_loader_ctx ctx; - struct { - struct bpf_map_desc hid_jmp_table; - } maps; - struct { - struct bpf_prog_desc hid_tail_call; - } progs; - struct { - int hid_tail_call_fd; - } links; -}; - -static inline int -entrypoints_bpf__hid_tail_call__attach(struct entrypoints_bpf *skel) -{ - int prog_fd = skel->progs.hid_tail_call.prog_fd; - int fd = skel_raw_tracepoint_open(NULL, prog_fd); - - if (fd > 0) - skel->links.hid_tail_call_fd = fd; - return fd; -} - -static inline int -entrypoints_bpf__attach(struct entrypoints_bpf *skel) -{ - int ret = 0; - - ret = ret < 0 ? ret : entrypoints_bpf__hid_tail_call__attach(skel); - return ret < 0 ? ret : 0; -} - -static inline void -entrypoints_bpf__detach(struct entrypoints_bpf *skel) -{ - skel_closenz(skel->links.hid_tail_call_fd); -} -static void -entrypoints_bpf__destroy(struct entrypoints_bpf *skel) -{ - if (!skel) - return; - entrypoints_bpf__detach(skel); - skel_closenz(skel->progs.hid_tail_call.prog_fd); - skel_closenz(skel->maps.hid_jmp_table.map_fd); - skel_free(skel); -} -static inline struct entrypoints_bpf * -entrypoints_bpf__open(void) -{ - struct entrypoints_bpf *skel; - - skel = skel_alloc(sizeof(*skel)); - if (!skel) - goto cleanup; - skel->ctx.sz = (void *)&skel->links - (void *)skel; - return skel; -cleanup: - entrypoints_bpf__destroy(skel); - return NULL; -} - -static inline int -entrypoints_bpf__load(struct entrypoints_bpf *skel) -{ - struct bpf_load_and_run_opts opts = {}; - int err; - - opts.ctx = (struct bpf_loader_ctx *)skel; - opts.data_sz = 2856; - opts.data = (void *)"\ -\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ -\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ 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-\0\xc5\x07\xca\xff\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x63\x71\0\0\0\0\ -\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\xf8\x09\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x90\ -\x0a\0\0\x7b\x01\0\0\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\0\x0a\0\0\x18\x61\0\0\ -\0\0\0\0\0\0\0\0\x88\x0a\0\0\x7b\x01\0\0\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\ -\x38\x0a\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\xd0\x0a\0\0\x7b\x01\0\0\0\0\0\0\x18\ -\x60\0\0\0\0\0\0\0\0\0\0\x40\x0a\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\xe0\x0a\0\0\ -\x7b\x01\0\0\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\x70\x0a\0\0\x18\x61\0\0\0\0\0\ -\0\0\0\0\0\0\x0b\0\0\x7b\x01\0\0\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\0\0\0\0\ -\x18\x61\0\0\0\0\0\0\0\0\0\0\xf8\x0a\0\0\x7b\x01\0\0\0\0\0\0\x61\x60\x08\0\0\0\ -\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x98\x0a\0\0\x63\x01\0\0\0\0\0\0\x61\x60\x0c\0\ -\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x9c\x0a\0\0\x63\x01\0\0\0\0\0\0\x79\x60\ -\x10\0\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\xa0\x0a\0\0\x7b\x01\0\0\0\0\0\0\x61\ -\xa0\x78\xff\0\0\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\xc8\x0a\0\0\x63\x01\0\0\0\0\0\ -\0\x18\x61\0\0\0\0\0\0\0\0\0\0\x10\x0b\0\0\xb7\x02\0\0\x14\0\0\0\xb7\x03\0\0\ -\x0c\0\0\0\xb7\x04\0\0\0\0\0\0\x85\0\0\0\xa7\0\0\0\xbf\x07\0\0\0\0\0\0\xc5\x07\ -\x91\xff\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\x80\x0a\0\0\x63\x70\x6c\0\0\0\0\0\ -\x77\x07\0\0\x20\0\0\0\x63\x70\x70\0\0\0\0\0\xb7\x01\0\0\x05\0\0\0\x18\x62\0\0\ -\0\0\0\0\0\0\0\0\x80\x0a\0\0\xb7\x03\0\0\x8c\0\0\0\x85\0\0\0\xa6\0\0\0\xbf\x07\ -\0\0\0\0\0\0\x18\x60\0\0\0\0\0\0\0\0\0\0\xf0\x0a\0\0\x61\x01\0\0\0\0\0\0\xd5\ -\x01\x02\0\0\0\0\0\xbf\x19\0\0\0\0\0\0\x85\0\0\0\xa8\0\0\0\xc5\x07\x7f\xff\0\0\ -\0\0\x63\x7a\x80\xff\0\0\0\0\x61\xa1\x78\xff\0\0\0\0\xd5\x01\x02\0\0\0\0\0\xbf\ -\x19\0\0\0\0\0\0\x85\0\0\0\xa8\0\0\0\x61\xa0\x80\xff\0\0\0\0\x63\x06\x28\0\0\0\ -\0\0\x18\x61\0\0\0\0\0\0\0\0\0\0\0\0\0\0\x61\x10\0\0\0\0\0\0\x63\x06\x18\0\0\0\ -\0\0\xb7\0\0\0\0\0\0\0\x95\0\0\0\0\0\0\0"; - err = bpf_load_and_run(&opts); - if (err < 0) - return err; - return 0; -} - -static inline struct entrypoints_bpf * -entrypoints_bpf__open_and_load(void) -{ - struct entrypoints_bpf *skel; - - skel = entrypoints_bpf__open(); - if (!skel) - return NULL; - if (entrypoints_bpf__load(skel)) { - entrypoints_bpf__destroy(skel); - return NULL; - } - return skel; -} - -__attribute__((unused)) static void -entrypoints_bpf__assert(struct entrypoints_bpf *s __attribute__((unused))) -{ -#ifdef __cplusplus -#define _Static_assert static_assert -#endif -#ifdef __cplusplus -#undef _Static_assert -#endif -} - -#endif /* __ENTRYPOINTS_BPF_SKEL_H__ */ diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 7216c3c7713d..06cc628e7bb4 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -3,7 +3,7 @@ /* * HID-BPF support for Linux * - * Copyright (c) 2022 Benjamin Tissoires + * Copyright (c) 2022-2024 Benjamin Tissoires */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt @@ -17,34 +17,11 @@ #include <linux/kfifo.h> #include <linux/minmax.h> #include <linux/module.h> -#include <linux/workqueue.h> #include "hid_bpf_dispatch.h" -#include "entrypoints/entrypoints.lskel.h"
struct hid_ops *hid_ops; EXPORT_SYMBOL(hid_ops);
-/** - * hid_bpf_device_event - Called whenever an event is coming in from the device - * - * @ctx: The HID-BPF context - * - * @return %0 on success and keep processing; a positive value to change the - * incoming size buffer; a negative error code to interrupt the processing - * of this event - * - * Declare an %fmod_ret tracing bpf program to this function and attach this - * program through hid_bpf_attach_prog() to have this helper called for - * any incoming event from the device itself. - * - * The function is called while on IRQ context, so we can not sleep. - */ -/* never used by the kernel but declared so we can load and attach a tracepoint */ -__weak noinline int hid_bpf_device_event(struct hid_bpf_ctx *ctx) -{ - return 0; -} - u8 * dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type, u8 *data, u32 *size, int interrupt) @@ -52,7 +29,6 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type struct hid_bpf_ctx_kern ctx_kern = { .ctx = { .hid = hdev, - .report_type = type, .allocated_size = hdev->bpf.allocated_data, .size = *size, }, @@ -86,11 +62,6 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type } rcu_read_unlock();
- ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_DEVICE_EVENT, &ctx_kern); - if (ret < 0) - return ERR_PTR(ret); - ret = ctx_kern.ctx.retval; - if (ret) { if (ret > ctx_kern.ctx.allocated_size) return ERR_PTR(-EINVAL); @@ -102,26 +73,6 @@ dispatch_hid_bpf_device_event(struct hid_device *hdev, enum hid_report_type type } EXPORT_SYMBOL_GPL(dispatch_hid_bpf_device_event);
-/** - * hid_bpf_rdesc_fixup - Called when the probe function parses the report - * descriptor of the HID device - * - * @ctx: The HID-BPF context - * - * @return 0 on success and keep processing; a positive value to change the - * incoming size buffer; a negative error code to interrupt the processing - * of this event - * - * Declare an %fmod_ret tracing bpf program to this function and attach this - * program through hid_bpf_attach_prog() to have this helper called before any - * parsing of the report descriptor by HID. - */ -/* never used by the kernel but declared so we can load and attach a tracepoint */ -__weak noinline int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx) -{ - return 0; -} - u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size) { int ret; @@ -133,16 +84,16 @@ u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *s }, };
+ if (!hdev->bpf.rdesc_ops) + goto ignore_bpf; + ctx_kern.data = kzalloc(ctx_kern.ctx.allocated_size, GFP_KERNEL); if (!ctx_kern.data) goto ignore_bpf;
memcpy(ctx_kern.data, rdesc, min_t(unsigned int, *size, HID_MAX_DESCRIPTOR_SIZE));
- if (hdev->bpf.rdesc_ops) - ret = hdev->bpf.rdesc_ops->hid_rdesc_fixup(&ctx_kern.ctx); - else - ret = hid_bpf_prog_run(hdev, HID_BPF_PROG_TYPE_RDESC_FIXUP, &ctx_kern); + ret = hdev->bpf.rdesc_ops->hid_rdesc_fixup(&ctx_kern.ctx); if (ret < 0) goto ignore_bpf;
@@ -242,39 +193,6 @@ int hid_bpf_reconnect(struct hid_device *hdev) return 0; }
-static int do_hid_bpf_attach_prog(struct hid_device *hdev, int prog_fd, struct bpf_prog *prog, - __u32 flags) -{ - int fd, err, prog_type; - - prog_type = hid_bpf_get_prog_attach_type(prog); - if (prog_type < 0) - return prog_type; - - if (prog_type >= HID_BPF_PROG_TYPE_MAX) - return -EINVAL; - - if (prog_type == HID_BPF_PROG_TYPE_DEVICE_EVENT) { - err = hid_bpf_allocate_event_data(hdev); - if (err) - return err; - } - - fd = __hid_bpf_attach_prog(hdev, prog_type, prog_fd, prog, flags); - if (fd < 0) - return fd; - - if (prog_type == HID_BPF_PROG_TYPE_RDESC_FIXUP) { - err = hid_bpf_reconnect(hdev); - if (err) { - close_fd(fd); - return err; - } - } - - return fd; -} - /* Disables missing prototype warnings */ __bpf_kfunc_start_defs();
@@ -303,57 +221,6 @@ hid_bpf_get_data(struct hid_bpf_ctx *ctx, unsigned int offset, const size_t rdwr return ctx_kern->data + offset; }
-/** - * hid_bpf_attach_prog - Attach the given @prog_fd to the given HID device - * - * @hid_id: the system unique identifier of the HID device - * @prog_fd: an fd in the user process representing the program to attach - * @flags: any logical OR combination of &enum hid_bpf_attach_flags - * - * @returns an fd of a bpf_link object on success (> %0), an error code otherwise. - * Closing this fd will detach the program from the HID device (unless the bpf_link - * is pinned to the BPF file system). - */ -/* called from syscall */ -__bpf_kfunc int -hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags) -{ - struct hid_device *hdev; - struct bpf_prog *prog; - int err, fd; - - if ((flags & ~HID_BPF_FLAG_MASK)) - return -EINVAL; - - hdev = hid_get_device(hid_id); - if (IS_ERR(hdev)) - return PTR_ERR(hdev); - - /* - * take a ref on the prog itself, it will be released - * on errors or when it'll be detached - */ - prog = bpf_prog_get(prog_fd); - if (IS_ERR(prog)) { - err = PTR_ERR(prog); - goto out_dev_put; - } - - fd = do_hid_bpf_attach_prog(hdev, prog_fd, prog, flags); - if (fd < 0) { - err = fd; - goto out_prog_put; - } - - return fd; - - out_prog_put: - bpf_prog_put(prog); - out_dev_put: - hid_put_device(hdev); - return err; -} - /** * hid_bpf_allocate_context - Allocate a context to the given HID device * @@ -583,21 +450,8 @@ static const struct btf_kfunc_id_set hid_bpf_kfunc_set = { .set = &hid_bpf_kfunc_ids, };
-/* our HID-BPF entrypoints */ -BTF_SET8_START(hid_bpf_fmodret_ids) -BTF_ID_FLAGS(func, hid_bpf_device_event) -BTF_ID_FLAGS(func, hid_bpf_rdesc_fixup) -BTF_ID_FLAGS(func, __hid_bpf_tail_call) -BTF_SET8_END(hid_bpf_fmodret_ids) - -static const struct btf_kfunc_id_set hid_bpf_fmodret_set = { - .owner = THIS_MODULE, - .set = &hid_bpf_fmodret_ids, -}; - /* for syscall HID-BPF */ BTF_KFUNCS_START(hid_bpf_syscall_kfunc_ids) -BTF_ID_FLAGS(func, hid_bpf_attach_prog) BTF_ID_FLAGS(func, hid_bpf_allocate_context, KF_ACQUIRE | KF_RET_NULL) BTF_ID_FLAGS(func, hid_bpf_release_context, KF_RELEASE) BTF_ID_FLAGS(func, hid_bpf_hw_request) @@ -622,8 +476,6 @@ int hid_bpf_connect_device(struct hid_device *hdev) break; } } - if (rcu_dereference(hdev->bpf.progs[HID_BPF_PROG_TYPE_DEVICE_EVENT])) - need_to_allocate = true; rcu_read_unlock();
/* only allocate BPF data if there are programs attached */ @@ -650,14 +502,12 @@ void hid_bpf_destroy_device(struct hid_device *hdev) /* mark the device as destroyed in bpf so we don't reattach it */ hdev->bpf.destroyed = true;
- __hid_bpf_destroy_device(hdev); __hid_bpf_ops_destroy_device(hdev); } EXPORT_SYMBOL_GPL(hid_bpf_destroy_device);
void hid_bpf_device_init(struct hid_device *hdev) { - spin_lock_init(&hdev->bpf.progs_lock); INIT_LIST_HEAD(&hdev->bpf.prog_list); mutex_init(&hdev->bpf.prog_list_lock); } @@ -670,37 +520,15 @@ static int __init hid_bpf_init(void) /* Note: if we exit with an error any time here, we would entirely break HID, which * is probably not something we want. So we log an error and return success. * - * This is not a big deal: the syscall allowing to attach a BPF program to a HID device - * will not be available, so nobody will be able to use the functionality. + * This is not a big deal: nobody will be able to use the functionality. */
- err = register_btf_fmodret_id_set(&hid_bpf_fmodret_set); - if (err) { - pr_warn("error while registering fmodret entrypoints: %d", err); - return 0; - } - - err = hid_bpf_preload_skel(); - if (err) { - pr_warn("error while preloading HID BPF dispatcher: %d", err); - return 0; - } - - /* register tracing kfuncs after we are sure we can load our preloaded bpf program */ - err = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &hid_bpf_kfunc_set); - if (err) { - pr_warn("error while setting HID BPF tracing kfuncs: %d", err); - return 0; - } - - /* register struct_ops kfuncs after we are sure we can load our preloaded bpf program */ err = register_btf_kfunc_id_set(BPF_PROG_TYPE_STRUCT_OPS, &hid_bpf_kfunc_set); if (err) { pr_warn("error while setting HID BPF tracing kfuncs: %d", err); return 0; }
- /* register syscalls after we are sure we can load our preloaded bpf program */ err = register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &hid_bpf_syscall_kfunc_set); if (err) { pr_warn("error while setting HID BPF syscall kfuncs: %d", err); @@ -710,15 +538,6 @@ static int __init hid_bpf_init(void) return 0; }
-static void __exit hid_bpf_exit(void) -{ - /* HID depends on us, so if we hit that code, we are guaranteed that hid - * has been removed and thus we do not need to clear the HID devices - */ - hid_bpf_free_links_and_skel(); -} - late_initcall(hid_bpf_init); -module_exit(hid_bpf_exit); MODULE_AUTHOR("Benjamin Tissoires"); MODULE_LICENSE("GPL"); diff --git a/drivers/hid/bpf/hid_bpf_dispatch.h b/drivers/hid/bpf/hid_bpf_dispatch.h index e52c43d81650..835e6f69f479 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.h +++ b/drivers/hid/bpf/hid_bpf_dispatch.h @@ -13,15 +13,7 @@ struct hid_bpf_ctx_kern { struct hid_device *hid_get_device(unsigned int hid_id); void hid_put_device(struct hid_device *hid); int hid_bpf_allocate_event_data(struct hid_device *hdev); -int hid_bpf_preload_skel(void); -void hid_bpf_free_links_and_skel(void); -int hid_bpf_get_prog_attach_type(struct bpf_prog *prog); -int __hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_type, int prog_fd, - struct bpf_prog *prog, __u32 flags); -void __hid_bpf_destroy_device(struct hid_device *hdev); void __hid_bpf_ops_destroy_device(struct hid_device *hdev); -int hid_bpf_prog_run(struct hid_device *hdev, enum hid_bpf_prog_type type, - struct hid_bpf_ctx_kern *ctx_kern); int hid_bpf_reconnect(struct hid_device *hdev);
struct bpf_prog; diff --git a/drivers/hid/bpf/hid_bpf_jmp_table.c b/drivers/hid/bpf/hid_bpf_jmp_table.c deleted file mode 100644 index 8a54ba447718..000000000000 --- a/drivers/hid/bpf/hid_bpf_jmp_table.c +++ /dev/null @@ -1,568 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only - -/* - * HID-BPF support for Linux - * - * Copyright (c) 2022 Benjamin Tissoires - */ - -#include <linux/bitops.h> -#include <linux/btf.h> -#include <linux/btf_ids.h> -#include <linux/circ_buf.h> -#include <linux/filter.h> -#include <linux/hid.h> -#include <linux/hid_bpf.h> -#include <linux/init.h> -#include <linux/module.h> -#include <linux/workqueue.h> -#include "hid_bpf_dispatch.h" -#include "entrypoints/entrypoints.lskel.h" - -#define HID_BPF_MAX_PROGS 1024 /* keep this in sync with preloaded bpf, - * needs to be a power of 2 as we use it as - * a circular buffer - */ - -#define NEXT(idx) (((idx) + 1) & (HID_BPF_MAX_PROGS - 1)) -#define PREV(idx) (((idx) - 1) & (HID_BPF_MAX_PROGS - 1)) - -/* - * represents one attached program stored in the hid jump table - */ -struct hid_bpf_prog_entry { - struct bpf_prog *prog; - struct hid_device *hdev; - enum hid_bpf_prog_type type; - u16 idx; -}; - -struct hid_bpf_jmp_table { - struct bpf_map *map; - struct hid_bpf_prog_entry entries[HID_BPF_MAX_PROGS]; /* compacted list, circular buffer */ - int tail, head; - struct bpf_prog *progs[HID_BPF_MAX_PROGS]; /* idx -> progs mapping */ - unsigned long enabled[BITS_TO_LONGS(HID_BPF_MAX_PROGS)]; -}; - -#define FOR_ENTRIES(__i, __start, __end) \ - for (__i = __start; CIRC_CNT(__end, __i, HID_BPF_MAX_PROGS); __i = NEXT(__i)) - -static struct hid_bpf_jmp_table jmp_table; - -static DEFINE_MUTEX(hid_bpf_attach_lock); /* held when attaching/detaching programs */ - -static void hid_bpf_release_progs(struct work_struct *work); - -static DECLARE_WORK(release_work, hid_bpf_release_progs); - -BTF_ID_LIST(hid_bpf_btf_ids) -BTF_ID(func, hid_bpf_device_event) /* HID_BPF_PROG_TYPE_DEVICE_EVENT */ -BTF_ID(func, hid_bpf_rdesc_fixup) /* HID_BPF_PROG_TYPE_RDESC_FIXUP */ - -static int hid_bpf_max_programs(enum hid_bpf_prog_type type) -{ - switch (type) { - case HID_BPF_PROG_TYPE_DEVICE_EVENT: - return HID_BPF_MAX_PROGS_PER_DEV; - case HID_BPF_PROG_TYPE_RDESC_FIXUP: - return 1; - default: - return -EINVAL; - } -} - -static int hid_bpf_program_count(struct hid_device *hdev, - struct bpf_prog *prog, - enum hid_bpf_prog_type type) -{ - int i, n = 0; - - if (type >= HID_BPF_PROG_TYPE_MAX) - return -EINVAL; - - if (type == HID_BPF_PROG_TYPE_RDESC_FIXUP && hdev->bpf.rdesc_ops) - n += 1; - - FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { - struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; - - if (type != HID_BPF_PROG_TYPE_UNDEF && entry->type != type) - continue; - - if (hdev && entry->hdev != hdev) - continue; - - if (prog && entry->prog != prog) - continue; - - n++; - } - - return n; -} - -__weak noinline int __hid_bpf_tail_call(struct hid_bpf_ctx *ctx) -{ - return 0; -} - -int hid_bpf_prog_run(struct hid_device *hdev, enum hid_bpf_prog_type type, - struct hid_bpf_ctx_kern *ctx_kern) -{ - struct hid_bpf_prog_list *prog_list; - int i, idx, err = 0; - - rcu_read_lock(); - prog_list = rcu_dereference(hdev->bpf.progs[type]); - - if (!prog_list) - goto out_unlock; - - for (i = 0; i < prog_list->prog_cnt; i++) { - idx = prog_list->prog_idx[i]; - - if (!test_bit(idx, jmp_table.enabled)) - continue; - - ctx_kern->ctx.index = idx; - err = __hid_bpf_tail_call(&ctx_kern->ctx); - if (err < 0) - break; - if (err) - ctx_kern->ctx.retval = err; - } - - out_unlock: - rcu_read_unlock(); - - return err; -} - -/* - * assign the list of programs attached to a given hid device. - */ -static void __hid_bpf_set_hdev_progs(struct hid_device *hdev, struct hid_bpf_prog_list *new_list, - enum hid_bpf_prog_type type) -{ - struct hid_bpf_prog_list *old_list; - - spin_lock(&hdev->bpf.progs_lock); - old_list = rcu_dereference_protected(hdev->bpf.progs[type], - lockdep_is_held(&hdev->bpf.progs_lock)); - rcu_assign_pointer(hdev->bpf.progs[type], new_list); - spin_unlock(&hdev->bpf.progs_lock); - synchronize_rcu(); - - kfree(old_list); -} - -/* - * allocate and populate the list of programs attached to a given hid device. - * - * Must be called under lock. - */ -static int hid_bpf_populate_hdev(struct hid_device *hdev, enum hid_bpf_prog_type type) -{ - struct hid_bpf_prog_list *new_list; - int i; - - if (type >= HID_BPF_PROG_TYPE_MAX || !hdev) - return -EINVAL; - - if (hdev->bpf.destroyed) - return 0; - - new_list = kzalloc(sizeof(*new_list), GFP_KERNEL); - if (!new_list) - return -ENOMEM; - - FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { - struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; - - if (entry->type == type && entry->hdev == hdev && - test_bit(entry->idx, jmp_table.enabled)) - new_list->prog_idx[new_list->prog_cnt++] = entry->idx; - } - - __hid_bpf_set_hdev_progs(hdev, new_list, type); - - return 0; -} - -static void __hid_bpf_do_release_prog(int map_fd, unsigned int idx) -{ - skel_map_delete_elem(map_fd, &idx); - jmp_table.progs[idx] = NULL; -} - -static void hid_bpf_release_progs(struct work_struct *work) -{ - int i, j, n, map_fd = -1; - bool hdev_destroyed; - - if (!jmp_table.map) - return; - - /* retrieve a fd of our prog_array map in BPF */ - map_fd = skel_map_get_fd_by_id(jmp_table.map->id); - if (map_fd < 0) - return; - - mutex_lock(&hid_bpf_attach_lock); /* protects against attaching new programs */ - - /* detach unused progs from HID devices */ - FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { - struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; - enum hid_bpf_prog_type type; - struct hid_device *hdev; - - if (test_bit(entry->idx, jmp_table.enabled)) - continue; - - /* we have an attached prog */ - if (entry->hdev) { - hdev = entry->hdev; - type = entry->type; - /* - * hdev is still valid, even if we are called after hid_destroy_device(): - * when hid_bpf_attach() gets called, it takes a ref on the dev through - * bus_find_device() - */ - hdev_destroyed = hdev->bpf.destroyed; - - hid_bpf_populate_hdev(hdev, type); - - /* mark all other disabled progs from hdev of the given type as detached */ - FOR_ENTRIES(j, i, jmp_table.head) { - struct hid_bpf_prog_entry *next; - - next = &jmp_table.entries[j]; - - if (test_bit(next->idx, jmp_table.enabled)) - continue; - - if (next->hdev == hdev && next->type == type) { - /* - * clear the hdev reference and decrement the device ref - * that was taken during bus_find_device() while calling - * hid_bpf_attach() - */ - next->hdev = NULL; - put_device(&hdev->dev); - } - } - - /* if type was rdesc fixup and the device is not gone, reconnect device */ - if (type == HID_BPF_PROG_TYPE_RDESC_FIXUP && !hdev_destroyed) - hid_bpf_reconnect(hdev); - } - } - - /* remove all unused progs from the jump table */ - FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { - struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; - - if (test_bit(entry->idx, jmp_table.enabled)) - continue; - - if (entry->prog) - __hid_bpf_do_release_prog(map_fd, entry->idx); - } - - /* compact the entry list */ - n = jmp_table.tail; - FOR_ENTRIES(i, jmp_table.tail, jmp_table.head) { - struct hid_bpf_prog_entry *entry = &jmp_table.entries[i]; - - if (!test_bit(entry->idx, jmp_table.enabled)) - continue; - - jmp_table.entries[n] = jmp_table.entries[i]; - n = NEXT(n); - } - - jmp_table.head = n; - - mutex_unlock(&hid_bpf_attach_lock); - - if (map_fd >= 0) - close_fd(map_fd); -} - -static void hid_bpf_release_prog_at(int idx) -{ - int map_fd = -1; - - /* retrieve a fd of our prog_array map in BPF */ - map_fd = skel_map_get_fd_by_id(jmp_table.map->id); - if (map_fd < 0) - return; - - __hid_bpf_do_release_prog(map_fd, idx); - - close(map_fd); -} - -/* - * Insert the given BPF program represented by its fd in the jmp table. - * Returns the index in the jump table or a negative error. - */ -static int hid_bpf_insert_prog(int prog_fd, struct bpf_prog *prog) -{ - int i, index = -1, map_fd = -1, err = -EINVAL; - - /* retrieve a fd of our prog_array map in BPF */ - map_fd = skel_map_get_fd_by_id(jmp_table.map->id); - - if (map_fd < 0) { - err = -EINVAL; - goto out; - } - - /* find the first available index in the jmp_table */ - for (i = 0; i < HID_BPF_MAX_PROGS; i++) { - if (!jmp_table.progs[i] && index < 0) { - /* mark the index as used */ - jmp_table.progs[i] = prog; - index = i; - __set_bit(i, jmp_table.enabled); - } - } - if (index < 0) { - err = -ENOMEM; - goto out; - } - - /* insert the program in the jump table */ - err = skel_map_update_elem(map_fd, &index, &prog_fd, 0); - if (err) - goto out; - - /* return the index */ - err = index; - - out: - if (err < 0) - __hid_bpf_do_release_prog(map_fd, index); - if (map_fd >= 0) - close_fd(map_fd); - return err; -} - -int hid_bpf_get_prog_attach_type(struct bpf_prog *prog) -{ - int prog_type = HID_BPF_PROG_TYPE_UNDEF; - int i; - - for (i = 0; i < HID_BPF_PROG_TYPE_MAX; i++) { - if (hid_bpf_btf_ids[i] == prog->aux->attach_btf_id) { - prog_type = i; - break; - } - } - - return prog_type; -} - -static void hid_bpf_link_release(struct bpf_link *link) -{ - struct hid_bpf_link *hid_link = - container_of(link, struct hid_bpf_link, link); - - __clear_bit(hid_link->hid_table_index, jmp_table.enabled); - schedule_work(&release_work); -} - -static void hid_bpf_link_dealloc(struct bpf_link *link) -{ - struct hid_bpf_link *hid_link = - container_of(link, struct hid_bpf_link, link); - - kfree(hid_link); -} - -static void hid_bpf_link_show_fdinfo(const struct bpf_link *link, - struct seq_file *seq) -{ - seq_printf(seq, - "attach_type:\tHID-BPF\n"); -} - -static const struct bpf_link_ops hid_bpf_link_lops = { - .release = hid_bpf_link_release, - .dealloc = hid_bpf_link_dealloc, - .show_fdinfo = hid_bpf_link_show_fdinfo, -}; - -/* called from syscall */ -noinline int -__hid_bpf_attach_prog(struct hid_device *hdev, enum hid_bpf_prog_type prog_type, - int prog_fd, struct bpf_prog *prog, __u32 flags) -{ - struct bpf_link_primer link_primer; - struct hid_bpf_link *link; - struct hid_bpf_prog_entry *prog_entry; - int cnt, err = -EINVAL, prog_table_idx = -1; - - mutex_lock(&hid_bpf_attach_lock); - - link = kzalloc(sizeof(*link), GFP_USER); - if (!link) { - err = -ENOMEM; - goto err_unlock; - } - - bpf_link_init(&link->link, BPF_LINK_TYPE_UNSPEC, - &hid_bpf_link_lops, prog); - - /* do not attach too many programs to a given HID device */ - cnt = hid_bpf_program_count(hdev, NULL, prog_type); - if (cnt < 0) { - err = cnt; - goto err_unlock; - } - - if (cnt >= hid_bpf_max_programs(prog_type)) { - err = -E2BIG; - goto err_unlock; - } - - prog_table_idx = hid_bpf_insert_prog(prog_fd, prog); - /* if the jmp table is full, abort */ - if (prog_table_idx < 0) { - err = prog_table_idx; - goto err_unlock; - } - - if (flags & HID_BPF_FLAG_INSERT_HEAD) { - /* take the previous prog_entry slot */ - jmp_table.tail = PREV(jmp_table.tail); - prog_entry = &jmp_table.entries[jmp_table.tail]; - } else { - /* take the next prog_entry slot */ - prog_entry = &jmp_table.entries[jmp_table.head]; - jmp_table.head = NEXT(jmp_table.head); - } - - /* we steal the ref here */ - prog_entry->prog = prog; - prog_entry->idx = prog_table_idx; - prog_entry->hdev = hdev; - prog_entry->type = prog_type; - - /* finally store the index in the device list */ - err = hid_bpf_populate_hdev(hdev, prog_type); - if (err) { - hid_bpf_release_prog_at(prog_table_idx); - goto err_unlock; - } - - link->hid_table_index = prog_table_idx; - - err = bpf_link_prime(&link->link, &link_primer); - if (err) - goto err_unlock; - - mutex_unlock(&hid_bpf_attach_lock); - - return bpf_link_settle(&link_primer); - - err_unlock: - mutex_unlock(&hid_bpf_attach_lock); - - kfree(link); - - return err; -} - -void __hid_bpf_destroy_device(struct hid_device *hdev) -{ - int type, i; - struct hid_bpf_prog_list *prog_list; - - rcu_read_lock(); - - for (type = 0; type < HID_BPF_PROG_TYPE_MAX; type++) { - prog_list = rcu_dereference(hdev->bpf.progs[type]); - - if (!prog_list) - continue; - - for (i = 0; i < prog_list->prog_cnt; i++) - __clear_bit(prog_list->prog_idx[i], jmp_table.enabled); - } - - rcu_read_unlock(); - - for (type = 0; type < HID_BPF_PROG_TYPE_MAX; type++) - __hid_bpf_set_hdev_progs(hdev, NULL, type); - - /* schedule release of all detached progs */ - schedule_work(&release_work); -} - -#define HID_BPF_PROGS_COUNT 1 - -static struct bpf_link *links[HID_BPF_PROGS_COUNT]; -static struct entrypoints_bpf *skel; - -void hid_bpf_free_links_and_skel(void) -{ - int i; - - /* the following is enough to release all programs attached to hid */ - if (jmp_table.map) - bpf_map_put_with_uref(jmp_table.map); - - for (i = 0; i < ARRAY_SIZE(links); i++) { - if (!IS_ERR_OR_NULL(links[i])) - bpf_link_put(links[i]); - } - entrypoints_bpf__destroy(skel); -} - -#define ATTACH_AND_STORE_LINK(__name) do { \ - err = entrypoints_bpf__##__name##__attach(skel); \ - if (err) \ - goto out; \ - \ - links[idx] = bpf_link_get_from_fd(skel->links.__name##_fd); \ - if (IS_ERR(links[idx])) { \ - err = PTR_ERR(links[idx]); \ - goto out; \ - } \ - \ - /* Avoid taking over stdin/stdout/stderr of init process. Zeroing out \ - * makes skel_closenz() a no-op later in iterators_bpf__destroy(). \ - */ \ - close_fd(skel->links.__name##_fd); \ - skel->links.__name##_fd = 0; \ - idx++; \ -} while (0) - -int hid_bpf_preload_skel(void) -{ - int err, idx = 0; - - skel = entrypoints_bpf__open(); - if (!skel) - return -ENOMEM; - - err = entrypoints_bpf__load(skel); - if (err) - goto out; - - jmp_table.map = bpf_map_get_with_uref(skel->maps.hid_jmp_table.map_fd); - if (IS_ERR(jmp_table.map)) { - err = PTR_ERR(jmp_table.map); - goto out; - } - - ATTACH_AND_STORE_LINK(hid_tail_call); - - return 0; -out: - hid_bpf_free_links_and_skel(); - return err; -} diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index 96495e977204..c0682db73aeb 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -4,7 +4,7 @@ #define __HID_BPF_H
#include <linux/bpf.h> -#include <linux/spinlock.h> +#include <linux/mutex.h> #include <uapi/linux/hid.h>
struct hid_device; @@ -24,11 +24,7 @@ struct hid_device; * * All of these fields are currently read-only. * - * @index: program index in the jump table. No special meaning (a smaller index - * doesn't mean the program will be executed before another program with - * a bigger index). * @hid: the ``struct hid_device`` representing the device itself - * @report_type: used for ``hid_bpf_device_event()`` * @allocated_size: Allocated size of data. * * This is how much memory is available and can be requested @@ -47,10 +43,8 @@ struct hid_device; * @retval: Return value of the previous program. */ struct hid_bpf_ctx { - __u32 index; const struct hid_device *hid; __u32 allocated_size; - enum hid_report_type report_type; union { __s32 retval; __s32 size; @@ -74,27 +68,13 @@ enum hid_bpf_attach_flags { HID_BPF_FLAG_MAX, };
-/* Following functions are tracepoints that BPF programs can attach to */ -int hid_bpf_device_event(struct hid_bpf_ctx *ctx); -int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx); - /* * Below is HID internal */
-/* internal function to call eBPF programs, not to be used by anybody */ -int __hid_bpf_tail_call(struct hid_bpf_ctx *ctx); - #define HID_BPF_MAX_PROGS_PER_DEV 64 #define HID_BPF_FLAG_MASK (((HID_BPF_FLAG_MAX - 1) << 1) - 1)
-/* types of HID programs to attach to */ -enum hid_bpf_prog_type { - HID_BPF_PROG_TYPE_UNDEF = -1, - HID_BPF_PROG_TYPE_DEVICE_EVENT, /* an event is emitted from the device */ - HID_BPF_PROG_TYPE_RDESC_FIXUP, - HID_BPF_PROG_TYPE_MAX, -};
struct hid_report_enum;
@@ -170,11 +150,6 @@ struct hid_bpf_ops { struct hid_device *hdev; } ____cacheline_aligned_in_smp;
-struct hid_bpf_prog_list { - u16 prog_idx[HID_BPF_MAX_PROGS_PER_DEV]; - u8 prog_cnt; -}; - /* stored in each device */ struct hid_bpf { u8 *device_data; /* allocated when a bpf program of type @@ -182,23 +157,13 @@ struct hid_bpf { * to this HID device */ u32 allocated_data; - - struct hid_bpf_prog_list __rcu *progs[HID_BPF_PROG_TYPE_MAX]; /* attached BPF progs */ bool destroyed; /* prevents the assignment of any progs */
- spinlock_t progs_lock; /* protects RCU update of progs */ - struct hid_bpf_ops *rdesc_ops; struct list_head prog_list; struct mutex prog_list_lock; /* protects RCU update of prog_list */ };
-/* specific HID-BPF link when a program is attached to a device */ -struct hid_bpf_link { - struct bpf_link link; - int hid_table_index; -}; - #ifdef CONFIG_HID_BPF u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, u8 *data, u32 *size, int interrupt);
I got a weird verifier error with a subprog once, so let's have a test for it.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- tools/testing/selftests/hid/hid_bpf.c | 41 +++++++++++++++++++++++++++++++++ tools/testing/selftests/hid/progs/hid.c | 24 +++++++++++++++++++ 2 files changed, 65 insertions(+)
diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c index 967dfe6b58cb..45e173db35bd 100644 --- a/tools/testing/selftests/hid/hid_bpf.c +++ b/tools/testing/selftests/hid/hid_bpf.c @@ -638,6 +638,47 @@ TEST_F(hid_bpf, raw_event) ASSERT_EQ(buf[2], 52); }
+/* + * Attach hid_first_event to the given uhid device, + * retrieve and open the matching hidraw node, + * inject one event in the uhid device, + * check that the program sees it and can change the data + */ +TEST_F(hid_bpf, subprog_raw_event) +{ + const struct test_program progs[] = { + { .name = "hid_subprog_first_event" }, + }; + __u8 buf[10] = {0}; + int err; + + LOAD_PROGRAMS(progs); + + /* inject one event */ + buf[0] = 1; + buf[1] = 42; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 6) TH_LOG("read_hidraw"); + ASSERT_EQ(buf[0], 1); + ASSERT_EQ(buf[2], 47); + + /* inject another event */ + memset(buf, 0, sizeof(buf)); + buf[0] = 1; + buf[1] = 47; + uhid_send_event(_metadata, self->uhid_fd, buf, 6); + + /* read the data from hidraw */ + memset(buf, 0, sizeof(buf)); + err = read(self->hidraw_fd, buf, sizeof(buf)); + ASSERT_EQ(err, 6) TH_LOG("read_hidraw"); + ASSERT_EQ(buf[2], 52); +} + /* * Ensures that we can attach/detach programs */ diff --git a/tools/testing/selftests/hid/progs/hid.c b/tools/testing/selftests/hid/progs/hid.c index 9adace26e8aa..efa3c7d292bc 100644 --- a/tools/testing/selftests/hid/progs/hid.c +++ b/tools/testing/selftests/hid/progs/hid.c @@ -35,6 +35,30 @@ struct hid_bpf_ops first_event = { .hid_id = 2, };
+int __hid_subprog_first_event(struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) +{ + __u8 *rw_data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 3 /* size */); + + if (!rw_data) + return 0; /* EPERM check */ + + rw_data[2] = rw_data[1] + 5; + + return hid_ctx->size; +} + +SEC("?struct_ops/hid_device_event") +int BPF_PROG(hid_subprog_first_event, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) +{ + return __hid_subprog_first_event(hid_ctx, type); +} + +SEC(".struct_ops.link") +struct hid_bpf_ops subprog_first_event = { + .hid_device_event = (void *)hid_subprog_first_event, + .hid_id = 2, +}; + SEC("?struct_ops/hid_device_event") int BPF_PROG(hid_second_event, struct hid_bpf_ctx *hid_ctx, enum hid_report_type type) {
Now that we are using struct_ops, the docs need to be changed.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- Documentation/hid/hid-bpf.rst | 145 +++++++++++++++++++----------------------- include/linux/hid_bpf.h | 8 +-- 2 files changed, 71 insertions(+), 82 deletions(-)
diff --git a/Documentation/hid/hid-bpf.rst b/Documentation/hid/hid-bpf.rst index 0765b3298ecf..bb8457bf15dd 100644 --- a/Documentation/hid/hid-bpf.rst +++ b/Documentation/hid/hid-bpf.rst @@ -132,16 +132,17 @@ input events. Available types of programs ===========================
-HID-BPF is built "on top" of BPF, meaning that we use tracing method to +HID-BPF is built "on top" of BPF, meaning that we use bpf struct_ops method to declare our programs.
HID-BPF has the following attachment types available:
-1. event processing/filtering with ``SEC("fmod_ret/hid_bpf_device_event")`` in libbpf +1. event processing/filtering with ``SEC("struct_ops/hid_device_event")`` in libbpf 2. actions coming from userspace with ``SEC("syscall")`` in libbpf -3. change of the report descriptor with ``SEC("fmod_ret/hid_bpf_rdesc_fixup")`` in libbpf +3. change of the report descriptor with ``SEC("struct_ops/hid_rdesc_fixup")`` or + ``SEC("struct_ops.s/hid_rdesc_fixup")`` in libbpf
-A ``hid_bpf_device_event`` is calling a BPF program when an event is received from +A ``hid_device_event`` is calling a BPF program when an event is received from the device. Thus we are in IRQ context and can act on the data or notify userspace. And given that we are in IRQ context, we can not talk back to the device.
@@ -149,37 +150,42 @@ A ``syscall`` means that userspace called the syscall ``BPF_PROG_RUN`` facility. This time, we can do any operations allowed by HID-BPF, and talking to the device is allowed.
-Last, ``hid_bpf_rdesc_fixup`` is different from the others as there can be only one +Last, ``hid_rdesc_fixup`` is different from the others as there can be only one BPF program of this type. This is called on ``probe`` from the driver and allows to -change the report descriptor from the BPF program. Once a ``hid_bpf_rdesc_fixup`` +change the report descriptor from the BPF program. Once a ``hid_rdesc_fixup`` program has been loaded, it is not possible to overwrite it unless the program which inserted it allows us by pinning the program and closing all of its fds pointing to it.
+Note that ``hid_rdesc_fixup`` can be declared as sleepable (``SEC("struct_ops.s/hid_rdesc_fixup")``). + + Developer API: ==============
-User API data structures available in programs: ------------------------------------------------ +Available ``struct_ops`` for HID-BPF: +-------------------------------------
.. kernel-doc:: include/linux/hid_bpf.h + :identifiers: hid_bpf_ops
-Available tracing functions to attach a HID-BPF program: ---------------------------------------------------------
-.. kernel-doc:: drivers/hid/bpf/hid_bpf_dispatch.c - :functions: hid_bpf_device_event hid_bpf_rdesc_fixup +User API data structures available in programs: +----------------------------------------------- + +.. kernel-doc:: include/linux/hid_bpf.h + :identifiers: hid_bpf_ctx hid_bpf_attach_flags
-Available API that can be used in all HID-BPF programs: -------------------------------------------------------- +Available API that can be used in all HID-BPF struct_ops programs: +------------------------------------------------------------------
.. kernel-doc:: drivers/hid/bpf/hid_bpf_dispatch.c - :functions: hid_bpf_get_data + :identifiers: hid_bpf_get_data
-Available API that can be used in syscall HID-BPF programs: ------------------------------------------------------------ +Available API that can be used in syscall HID-BPF programs or in sleepable HID-BPF struct_ops programs: +-------------------------------------------------------------------------------------------------------
.. kernel-doc:: drivers/hid/bpf/hid_bpf_dispatch.c - :functions: hid_bpf_attach_prog hid_bpf_hw_request hid_bpf_hw_output_report hid_bpf_input_report hid_bpf_allocate_context hid_bpf_release_context + :identifiers: hid_bpf_hw_request hid_bpf_hw_output_report hid_bpf_input_report hid_bpf_allocate_context hid_bpf_release_context
General overview of a HID-BPF program ===================================== @@ -222,8 +228,10 @@ This allows the following: Effect of a HID-BPF program ---------------------------
-For all HID-BPF attachment types except for :c:func:`hid_bpf_rdesc_fixup`, several eBPF -programs can be attached to the same device. +For all HID-BPF attachment types except for :c:func:`hid_rdesc_fixup`, several eBPF +programs can be attached to the same device. If a HID-BPF struct_ops has a +:c:func:`hid_rdesc_fixup` while another is already attached to the device, the +kernel will return `-EINVAL` when attaching the struct_ops.
Unless ``HID_BPF_FLAG_INSERT_HEAD`` is added to the flags while attaching the program, the new program is appended at the end of the list. @@ -234,8 +242,8 @@ from the device. Note that if there are multiple programs using the ``HID_BPF_FLAG_INSERT_HEAD`` flag, only the most recently loaded one is actually the first in the list.
-``SEC("fmod_ret/hid_bpf_device_event")`` -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +``SEC("struct_ops/hid_device_event")`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Whenever a matching event is raised, the eBPF programs are called one after the other and are working on the same data buffer. @@ -258,17 +266,17 @@ with, userspace needs to refer to the device by its unique system id (the last 4 in the sysfs path: ``/sys/bus/hid/devices/xxxx:yyyy:zzzz:0000``).
To retrieve a context associated with the device, the program must call -:c:func:`hid_bpf_allocate_context` and must release it with :c:func:`hid_bpf_release_context` +hid_bpf_allocate_context() and must release it with hid_bpf_release_context() before returning. Once the context is retrieved, one can also request a pointer to kernel memory with -:c:func:`hid_bpf_get_data`. This memory is big enough to support all input/output/feature +hid_bpf_get_data(). This memory is big enough to support all input/output/feature reports of the given device.
-``SEC("fmod_ret/hid_bpf_rdesc_fixup")`` -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +``SEC("struct_ops/hid_rdesc_fixup")`` +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The ``hid_bpf_rdesc_fixup`` program works in a similar manner to -``.report_fixup`` of ``struct hid_driver``. +The ``hid_rdesc_fixup`` program works in a similar manner to ``.report_fixup`` +of ``struct hid_driver``.
When the device is probed, the kernel sets the data buffer of the context with the content of the report descriptor. The memory associated with that buffer is @@ -277,33 +285,31 @@ content of the report descriptor. The memory associated with that buffer is The eBPF program can modify the data buffer at-will and the kernel uses the modified content and size as the report descriptor.
-Whenever a ``SEC("fmod_ret/hid_bpf_rdesc_fixup")`` program is attached (if no -program was attached before), the kernel immediately disconnects the HID device -and does a reprobe. +Whenever a struct_ops containing a ``SEC("struct_ops/hid_rdesc_fixup")`` program +is attached (if no program was attached before), the kernel immediately disconnects +the HID device and does a reprobe.
-In the same way, when the ``SEC("fmod_ret/hid_bpf_rdesc_fixup")`` program is -detached, the kernel issues a disconnect on the device. +In the same way, when this struct_ops is detached, the kernel issues a disconnect +on the device.
There is no ``detach`` facility in HID-BPF. Detaching a program happens when -all the user space file descriptors pointing at a program are closed. +all the user space file descriptors pointing at a HID-BPF struct_ops link are closed. Thus, if we need to replace a report descriptor fixup, some cooperation is required from the owner of the original report descriptor fixup. -The previous owner will likely pin the program in the bpffs, and we can then +The previous owner will likely pin the struct_ops link in the bpffs, and we can then replace it through normal bpf operations.
Attaching a bpf program to a device ===================================
-``libbpf`` does not export any helper to attach a HID-BPF program. -Users need to use a dedicated ``syscall`` program which will call -``hid_bpf_attach_prog(hid_id, program_fd, flags)``. +We now use standard struct_ops attachment through ``bpf_map__attach_struct_ops()``. +But given that we need to attach a struct_ops to a dedicated HID device, the caller +must set ``hid_id`` in the struct_ops map before loading the program in the kernel.
``hid_id`` is the unique system ID of the HID device (the last 4 numbers in the sysfs path: ``/sys/bus/hid/devices/xxxx:yyyy:zzzz:0000``)
-``progam_fd`` is the opened file descriptor of the program to attach. - -``flags`` is of type ``enum hid_bpf_attach_flags``. +One can also set ``flags``, which is of type ``enum hid_bpf_attach_flags``.
We can not rely on hidraw to bind a BPF program to a HID device. hidraw is an artefact of the processing of the HID device, and is not stable. Some drivers @@ -358,32 +364,15 @@ For that, we can create a basic skeleton for our BPF program:: extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx, unsigned int offset, const size_t __sz) __ksym; - extern int hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, u32 flags) __ksym;
struct { __uint(type, BPF_MAP_TYPE_RINGBUF); __uint(max_entries, 4096 * 64); } ringbuf SEC(".maps");
- struct attach_prog_args { - int prog_fd; - unsigned int hid; - unsigned int flags; - int retval; - }; - - SEC("syscall") - int attach_prog(struct attach_prog_args *ctx) - { - ctx->retval = hid_bpf_attach_prog(ctx->hid, - ctx->prog_fd, - ctx->flags); - return 0; - } - __u8 current_value = 0;
- SEC("?fmod_ret/hid_bpf_device_event") + SEC("struct_ops/hid_device_event") int BPF_PROG(filter_switch, struct hid_bpf_ctx *hid_ctx) { __u8 *data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 192 /* size */); @@ -407,37 +396,37 @@ For that, we can create a basic skeleton for our BPF program:: return 0; }
-To attach ``filter_switch``, userspace needs to call the ``attach_prog`` syscall -program first:: + SEC(".struct_ops.link") + struct hid_bpf_ops haptic_tablet = { + .hid_device_event = (void *)filter_switch, + }; + + +To attach ``haptic_tablet``, userspace needs to set ``hid_id`` first::
static int attach_filter(struct hid *hid_skel, int hid_id) { - int err, prog_fd; - int ret = -1; - struct attach_prog_args args = { - .hid = hid_id, - }; - DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattrs, - .ctx_in = &args, - .ctx_size_in = sizeof(args), - ); + int err, link_fd;
- args.prog_fd = bpf_program__fd(hid_skel->progs.filter_switch); + hid_skel->struct_ops.haptic_tablet->hid_id = hid_id; + err = hid__load(skel); + if (err) + return err;
- prog_fd = bpf_program__fd(hid_skel->progs.attach_prog); - - err = bpf_prog_test_run_opts(prog_fd, &tattrs); - if (err) - return err; + link_fd = bpf_map__attach_struct_ops(hid_skel->maps.haptic_tablet); + if (!link_fd) { + fprintf(stderr, "can not attach HID-BPF program: %m\n"); + return -1; + }
- return args.retval; /* the fd of the created bpf_link */ + return link_fd; /* the fd of the created bpf_link */ }
Our userspace program can now listen to notifications on the ring buffer, and is awaken only when the value changes.
When the userspace program doesn't need to listen to events anymore, it can just -close the returned fd from :c:func:`attach_filter`, which will tell the kernel to +close the returned bpf link from :c:func:`attach_filter`, which will tell the kernel to detach the program from the HID device.
Of course, in other use cases, the userspace program can also pin the fd to the diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index c0682db73aeb..36cfaf092d0f 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -20,11 +20,9 @@ struct hid_device; * struct hid_bpf_ctx - User accessible data for all HID programs * * ``data`` is not directly accessible from the context. We need to issue - * a call to ``hid_bpf_get_data()`` in order to get a pointer to that field. + * a call to hid_bpf_get_data() in order to get a pointer to that field. * - * All of these fields are currently read-only. - * - * @hid: the ``struct hid_device`` representing the device itself + * @hid: the &struct hid_device representing the device itself * @allocated_size: Allocated size of data. * * This is how much memory is available and can be requested @@ -41,6 +39,8 @@ struct hid_device; * ``size`` must always be less or equal than ``allocated_size`` (it is enforced * once all BPF programs have been run). * @retval: Return value of the previous program. + * + * ``hid`` and ``allocated_size`` are read-only, ``size`` and ``retval`` are read-write. */ struct hid_bpf_ctx { const struct hid_device *hid;
This is the current decision we took: we don't provide automatic loading of HID-BPF by the kernel directly, but rely on an external tool for it.
This tool is currently udev-hid-bpf, so let's make people aware of it.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- Documentation/hid/hid-bpf.rst | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/Documentation/hid/hid-bpf.rst b/Documentation/hid/hid-bpf.rst index bb8457bf15dd..7b151a2aef63 100644 --- a/Documentation/hid/hid-bpf.rst +++ b/Documentation/hid/hid-bpf.rst @@ -129,6 +129,23 @@ When a BPF program needs to emit input events, it needs to talk with the HID protocol, and rely on the HID kernel processing to translate the HID data into input events.
+In-tree HID-BPF programs and ``udev-hid-bpf`` +============================================= + +Official device fixes are shipped in the kernel tree as source in the +``drivers/hid/bpf/progs`` directory. This allows to add selftests to them in +``tools/testing/selftests/hid``. + +However, the compilation of these objects is not part of a regular kernel compilation +given that they need an external tool to be loaded. This tool is currently +`udev-hid-bpf https://libevdev.pages.freedesktop.org/udev-hid-bpf/index.html`_. + +For convenience, that external repository duplicates the files from here in +``drivers/hid/bpf/progs`` into its own ``src/bpf/stable`` directory. This allows +distributions to not have to pull the entire kernel source tree to ship and package +those HID-BPF fixes. ``udev-hid-bpf`` also has capabilities of handling multiple +objects files depending on the kernel the user is running. + Available types of programs ===========================
warning: unused variable ‘tilt’ [-Wunused-variable]
Signed-off-by: Peter Hutterer peter.hutterer@who-t.net Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/progs/XPPen__Artist24.bpf.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c b/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c index bc0b85c38445..d4d062c3a653 100644 --- a/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c +++ b/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c @@ -158,7 +158,6 @@ int BPF_PROG(xppen_24_fix_eraser, struct hid_bpf_ctx *hctx) __u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */); __u8 current_state, changed_state; bool prev_tip; - __u16 tilt;
if (!data) return 0; /* EPERM check */
There is no real reasons to paper over warnings for such small programs.
Signed-off-by: Benjamin Tissoires bentiss@kernel.org --- drivers/hid/bpf/progs/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hid/bpf/progs/Makefile b/drivers/hid/bpf/progs/Makefile index 63ed7e02adf1..ec1fc642fd63 100644 --- a/drivers/hid/bpf/progs/Makefile +++ b/drivers/hid/bpf/progs/Makefile @@ -56,7 +56,7 @@ clean:
%.bpf.o: %.bpf.c vmlinux.h $(BPFOBJ) | $(OUTPUT) $(call msg,BPF,$@) - $(Q)$(CLANG) -g -O2 --target=bpf $(INCLUDES) \ + $(Q)$(CLANG) -g -O2 --target=bpf -Wall -Werror $(INCLUDES) \ -c $(filter %.c,$^) -o $@ && \ $(LLVM_STRIP) -g $@
linux-kselftest-mirror@lists.linaro.org
-
Alexei Starovoitov -
Benjamin Tissoires -
kernel test robot