September 2024 - Linux-stable-mirror

[PATCH RFC v2 00/10] extensible syscalls: CHECK_FIELDS to allow for easier feature detection

by Aleksa Sarai

This is something that I've been thinking about for a while. We had a discussion at LPC 2020 about this[1] but the proposals suggested there never materialised. In short, it is quite difficult for userspace to detect the feature capability of syscalls at runtime. This is something a lot of programs want to do, but they are forced to create elaborate scenarios to try to figure out if a feature is supported without causing damage to the system. For the vast majority of cases, each individual feature also needs to be tested individually (because syscall results are all-or-nothing), so testing even a single syscall's feature set can easily inflate the startup time of programs. This patchset implements the fairly minimal design I proposed in this talk[2] and in some old LKML threads (though I can't find the exact references ATM). The general flow looks like: 1. Userspace will indicate to the kernel that a syscall should a be no-op by setting the top bit of the extensible struct size argument. We will almost certainly never support exabyte sized structs, so the top bits are free for us to use as makeshift flag bits. This is preferable to using the per-syscall flag field inside the structure because seccomp can easily detect the bit in the flag and allow the probe or forcefully return -EEXTSYS_NOOP. 2. The kernel will then fill the provided structure with every valid bit pattern that the current kernel understands. For flags or other bitflag-like fields, this is the set of valid flags or bits. For pointer fields or fields that take an arbitrary value, the field has every bit set (0xFF... to fill the field) to indicate that any value is valid in the field. 3. The syscall then returns -EEXTSYS_NOOP which is an errno that will only ever be used for this purpose (so userspace can be sure that the request succeeded). On older kernels, the syscall will return a different error (usually -E2BIG or -EFAULT) and userspace can do their old-fashioned checks. 4. Userspace can then check which flags and fields are supported by looking at the fields in the returned structure. Flags are checked by doing an AND with the flags field, and field support can checked by comparing to 0. In principle you could just AND the entire structure if you wanted to do this check generically without caring about the structure contents (this is what libraries might consider doing). Userspace can even find out the internal kernel structure size by passing a PAGE_SIZE buffer and seeing how many bytes are non-zero. As with copy_struct_from_user(), this is designed to be forward- and backwards- compatible. This allows programas to get a one-shot understanding of what features a syscall supports without having to do any elaborate setups or tricks to detect support for destructive features. Flags can simply be ANDed to check if they are in the supported set, and fields can just be checked to see if they are non-zero. This patchset is IMHO the simplest way we can add the ability to introspect the feature set of extensible struct (copy_struct_from_user) syscalls. It doesn't preclude the chance of a more generic mechanism being added later. The intended way of using this interface to get feature information looks something like the following (imagine that openat2 has gained a new field and a new flag in the future): static bool openat2_no_automount_supported; static bool openat2_cwd_fd_supported; int check_openat2_support(void) { int err; struct open_how how = {}; err = openat2(AT_FDCWD, ".", &how, CHECK_FIELDS | sizeof(how)); assert(err < 0); switch (errno) { case EFAULT: case E2BIG: /* Old kernel... */ check_support_the_old_way(); break; case EEXTSYS_NOOP: openat2_no_automount_supported = (how.flags & RESOLVE_NO_AUTOMOUNT); openat2_cwd_fd_supported = (how.cwd_fd != 0); break; } } This series adds CHECK_FIELDS support for the following extensible struct syscalls, as they are quite likely to grow flags in the near future: * openat2 * clone3 * mount_setattr [1]: https://lwn.net/Articles/830666/ [2]: https://youtu.be/ggD-eb3yPVs Signed-off-by: Aleksa Sarai <cyphar(a)cyphar.com> --- Changes in v2: - Add CHECK_FIELDS support to mount_setattr(2). - Fix build failure on architectures with custom errno values. - Rework selftests to use the tools/ uAPI headers rather than custom defining EEXTSYS_NOOP. - Make sure we return -EINVAL and -E2BIG for invalid sizes even if CHECK_FIELDS is set, and add some tests for that. - v1: <https://lore.kernel.org/r/20240902-extensible-structs-check_fields-v1-0-545…> --- Aleksa Sarai (10): uaccess: add copy_struct_to_user helper sched_getattr: port to copy_struct_to_user openat2: explicitly return -E2BIG for (usize > PAGE_SIZE) openat2: add CHECK_FIELDS flag to usize argument selftests: openat2: add 0xFF poisoned data after misaligned struct selftests: openat2: add CHECK_FIELDS selftests clone3: add CHECK_FIELDS flag to usize argument selftests: clone3: add CHECK_FIELDS selftests mount_setattr: add CHECK_FIELDS flag to usize argument selftests: mount_setattr: add CHECK_FIELDS selftest arch/alpha/include/uapi/asm/errno.h | 3 + arch/mips/include/uapi/asm/errno.h | 3 + arch/parisc/include/uapi/asm/errno.h | 3 + arch/sparc/include/uapi/asm/errno.h | 3 + fs/namespace.c | 17 ++ fs/open.c | 18 ++ include/linux/uaccess.h | 98 ++++++++ include/uapi/asm-generic/errno.h | 3 + include/uapi/linux/openat2.h | 2 + kernel/fork.c | 30 ++- kernel/sched/syscalls.c | 42 +--- tools/arch/alpha/include/uapi/asm/errno.h | 3 + tools/arch/mips/include/uapi/asm/errno.h | 3 + tools/arch/parisc/include/uapi/asm/errno.h | 3 + tools/arch/sparc/include/uapi/asm/errno.h | 3 + tools/include/uapi/asm-generic/errno.h | 3 + tools/include/uapi/asm-generic/posix_types.h | 101 ++++++++ tools/testing/selftests/clone3/.gitignore | 1 + tools/testing/selftests/clone3/Makefile | 4 +- .../testing/selftests/clone3/clone3_check_fields.c | 264 +++++++++++++++++++++ tools/testing/selftests/mount_setattr/Makefile | 2 +- .../selftests/mount_setattr/mount_setattr_test.c | 53 ++++- tools/testing/selftests/openat2/Makefile | 2 + tools/testing/selftests/openat2/openat2_test.c | 165 ++++++++++++- 24 files changed, 778 insertions(+), 51 deletions(-) --- base-commit: 431c1646e1f86b949fa3685efc50b660a364c2b6 change-id: 20240803-extensible-structs-check_fields-a47e94cef691 Best regards, -- Aleksa Sarai <cyphar(a)cyphar.com>

2 weeks

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[PATCH 11/12] xhci: Set quirky xHC PCI hosts to D3 _after_ stopping and freeing them.

by Mathias Nyman

PCI xHC host should be stopped and xhci driver memory freed before putting host to PCI D3 state during PCI remove callback. Hosts with XHCI_SPURIOUS_WAKEUP quirk did this the wrong way around and set the host to D3 before calling usb_hcd_pci_remove(dev), which will access the host to stop it, and then free xhci. Fixes: f1f6d9a8b540 ("xhci: don't dereference a xhci member after removing xhci") Cc: stable(a)vger.kernel.org Signed-off-by: Mathias Nyman <mathias.nyman(a)linux.intel.com> --- drivers/usb/host/xhci-pci.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c index 526739af2070..de50f5ba60df 100644 --- a/drivers/usb/host/xhci-pci.c +++ b/drivers/usb/host/xhci-pci.c @@ -657,8 +657,10 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id) void xhci_pci_remove(struct pci_dev *dev) { struct xhci_hcd *xhci; + bool set_power_d3; xhci = hcd_to_xhci(pci_get_drvdata(dev)); + set_power_d3 = xhci->quirks & XHCI_SPURIOUS_WAKEUP; xhci->xhc_state |= XHCI_STATE_REMOVING; @@ -671,11 +673,11 @@ void xhci_pci_remove(struct pci_dev *dev) xhci->shared_hcd = NULL; } + usb_hcd_pci_remove(dev); + /* Workaround for spurious wakeups at shutdown with HSW */ - if (xhci->quirks & XHCI_SPURIOUS_WAKEUP) + if (set_power_d3) pci_set_power_state(dev, PCI_D3hot); - - usb_hcd_pci_remove(dev); } EXPORT_SYMBOL_NS_GPL(xhci_pci_remove, xhci); -- 2.25.1

2 weeks

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[PATCH] drm/panthor: Don't declare a queue blocked if deferred operations are pending

by Boris Brezillon

If deferred operations are pending, we want to wait for those to land before declaring the queue blocked on a SYNC_WAIT. We need this to deal with the case where the sync object is signalled through a deferred SYNC_{ADD,SET} from the same queue. If we don't do that and the group gets scheduled out before the deferred SYNC_{SET,ADD} is executed, we'll end up with a timeout, because no external SYNC_{SET,ADD} will make the scheduler reconsider the group for execution. Fixes: de8548813824 ("drm/panthor: Add the scheduler logical block") Cc: <stable(a)vger.kernel.org> Signed-off-by: Boris Brezillon <boris.brezillon(a)collabora.com> --- drivers/gpu/drm/panthor/panthor_sched.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index 41260cf4beb8..201d5e7a921e 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -1103,7 +1103,13 @@ cs_slot_sync_queue_state_locked(struct panthor_device *ptdev, u32 csg_id, u32 cs list_move_tail(&group->wait_node, &group->ptdev->scheduler->groups.waiting); } - group->blocked_queues |= BIT(cs_id); + + /* The queue is only blocked if there's no deferred operation + * pending, which can be checked through the scoreboard status. + */ + if (!cs_iface->output->status_scoreboards) + group->blocked_queues |= BIT(cs_id); + queue->syncwait.gpu_va = cs_iface->output->status_wait_sync_ptr; queue->syncwait.ref = cs_iface->output->status_wait_sync_value; status_wait_cond = cs_iface->output->status_wait & CS_STATUS_WAIT_SYNC_COND_MASK; -- 2.46.0

2 weeks

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[PATCH] drm/panthor: Don't add write fences to the shared BOs

by Boris Brezillon

The only user (the mesa gallium driver) is already assuming explicit synchronization and doing the export/import dance on shared BOs. The only reason we were registering ourselves as writers on external BOs is because Xe, which was the reference back when we developed Panthor, was doing so. Turns out Xe was wrong, and we really want bookkeep on all registered fences, so userspace can explicitly upgrade those to read/write when needed. Fixes: 4bdca1150792 ("drm/panthor: Add the driver frontend block") Cc: Matthew Brost <matthew.brost(a)intel.com> Cc: Simona Vetter <simona.vetter(a)ffwll.ch> Cc: <stable(a)vger.kernel.org> Signed-off-by: Boris Brezillon <boris.brezillon(a)collabora.com> --- drivers/gpu/drm/panthor/panthor_sched.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) diff --git a/drivers/gpu/drm/panthor/panthor_sched.c b/drivers/gpu/drm/panthor/panthor_sched.c index 9a0ff48f7061..41260cf4beb8 100644 --- a/drivers/gpu/drm/panthor/panthor_sched.c +++ b/drivers/gpu/drm/panthor/panthor_sched.c @@ -3423,13 +3423,8 @@ void panthor_job_update_resvs(struct drm_exec *exec, struct drm_sched_job *sched { struct panthor_job *job = container_of(sched_job, struct panthor_job, base); - /* Still not sure why we want USAGE_WRITE for external objects, since I - * was assuming this would be handled through explicit syncs being imported - * to external BOs with DMA_BUF_IOCTL_IMPORT_SYNC_FILE, but other drivers - * seem to pass DMA_RESV_USAGE_WRITE, so there must be a good reason. - */ panthor_vm_update_resvs(job->group->vm, exec, &sched_job->s_fence->finished, - DMA_RESV_USAGE_BOOKKEEP, DMA_RESV_USAGE_WRITE); + DMA_RESV_USAGE_BOOKKEEP, DMA_RESV_USAGE_BOOKKEEP); } void panthor_sched_unplug(struct panthor_device *ptdev) -- 2.46.0

2 weeks

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[PATCH v2] cxl/region: Fix bad logic for finding a free switch cxl decoder

by Zijun Hu

From: Zijun Hu <quic_zijuhu(a)quicinc.com> It is bad for current match_free_decoder()'s logic to find a free switch cxl decoder as explained below: - If all child decoders are sorted by ID in ascending order, then current logic can be simplified as below one: static int match_free_decoder(struct device *dev, void *data) { struct cxl_decoder *cxld; if (!is_switch_decoder(dev)) return 0; cxld = to_cxl_decoder(dev); return cxld->region ? 0 : 1; } dev = device_find_child(&port->dev, NULL, match_free_decoder); which does not also need to modify device_find_child()'s match data. - If all child decoders are NOT sorted by ID in ascending order, then current logic are wrong as explained below: F: free, (cxld->region == NULL) B: busy, (cxld->region != NULL) S(n)F : State of switch cxl_decoder with ID n is Free S(n)B : State of switch cxl_decoder with ID n is Busy Provided there are 2 child decoders: S(1)F -> S(0)B, then current logic will fail to find a free decoder even if there are a free one with ID 1 Anyway, current logic is not good, fixed by finding a free switch cxl decoder with minimal ID. Fixes: 384e624bb211 ("cxl/region: Attach endpoint decoders") Closes: https://lore.kernel.org/all/cdfc6f98-1aa0-4cb5-bd7d-93256552c39b@icloud.com/ Cc: stable(a)vger.kernel.org Signed-off-by: Zijun Hu <quic_zijuhu(a)quicinc.com> --- Changes in v2: - Correct title and commit message - Link to v1: https://lore.kernel.org/r/20240903-fix_cxld-v1-1-61acba7198ae@quicinc.com --- drivers/cxl/core/region.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c index 21ad5f242875..b9607b4fc40b 100644 --- a/drivers/cxl/core/region.c +++ b/drivers/cxl/core/region.c @@ -797,21 +797,26 @@ static size_t show_targetN(struct cxl_region *cxlr, char *buf, int pos) static int match_free_decoder(struct device *dev, void *data) { struct cxl_decoder *cxld; - int *id = data; + struct cxl_decoder *target_cxld; + struct device **target_device = data; if (!is_switch_decoder(dev)) return 0; cxld = to_cxl_decoder(dev); - - /* enforce ordered allocation */ - if (cxld->id != *id) + if (cxld->region) return 0; - if (!cxld->region) - return 1; - - (*id)++; + if (!*target_device) { + *target_device = get_device(dev); + return 0; + } + /* enforce ordered allocation */ + target_cxld = to_cxl_decoder(*target_device); + if (cxld->id < target_cxld->id) { + put_device(*target_device); + *target_device = get_device(dev); + } return 0; } @@ -839,8 +844,7 @@ cxl_region_find_decoder(struct cxl_port *port, struct cxl_endpoint_decoder *cxled, struct cxl_region *cxlr) { - struct device *dev; - int id = 0; + struct device *dev = NULL; if (port == cxled_to_port(cxled)) return &cxled->cxld; @@ -849,7 +853,8 @@ cxl_region_find_decoder(struct cxl_port *port, dev = device_find_child(&port->dev, &cxlr->params, match_auto_decoder); else - dev = device_find_child(&port->dev, &id, match_free_decoder); + /* Need to put_device(@dev) after use */ + device_for_each_child(&port->dev, &dev, match_free_decoder); if (!dev) return NULL; /* --- base-commit: 67784a74e258a467225f0e68335df77acd67b7ab change-id: 20240903-fix_cxld-4f6575a90619 Best regards, -- Zijun Hu <quic_zijuhu(a)quicinc.com>

2 weeks

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[PATCH 2/2 4.19.y] ALSA: usb-audio: Fix gpf in snd_usb_pipe_sanity_check

by Hillf Danton

[ Upstream commit 5d78e1c2b7f4be00bbe62141603a631dc7812f35 ] syzbot found the following crash on: general protection fault: 0000 [#1] SMP KASAN RIP: 0010:snd_usb_pipe_sanity_check+0x80/0x130 sound/usb/helper.c:75 Call Trace: snd_usb_motu_microbookii_communicate.constprop.0+0xa0/0x2fb sound/usb/quirks.c:1007 snd_usb_motu_microbookii_boot_quirk sound/usb/quirks.c:1051 [inline] snd_usb_apply_boot_quirk.cold+0x163/0x370 sound/usb/quirks.c:1280 usb_audio_probe+0x2ec/0x2010 sound/usb/card.c:576 usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361 really_probe+0x281/0x650 drivers/base/dd.c:548 .... It was introduced in commit 801ebf1043ae for checking pipe and endpoint types. It is fixed by adding a check of the ep pointer in question. BugLink: https://syzkaller.appspot.com/bug?extid=d59c4387bfb6eced94e2 Reported-by: syzbot <syzbot+d59c4387bfb6eced94e2(a)syzkaller.appspotmail.com> Fixes: 801ebf1043ae ("ALSA: usb-audio: Sanity checks for each pipe and EP types") Cc: Andrey Konovalov <andreyknvl(a)google.com> Signed-off-by: Hillf Danton <hdanton(a)sina.com> Signed-off-by: Takashi Iwai <tiwai(a)suse.de> Signed-off-by: Dan Carpenter <dan.carpenter(a)linaro.org> --- sound/usb/helper.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sound/usb/helper.c b/sound/usb/helper.c index b1cc9499c57e..029489b490ca 100644 --- a/sound/usb/helper.c +++ b/sound/usb/helper.c @@ -85,7 +85,7 @@ int snd_usb_pipe_sanity_check(struct usb_device *dev, unsigned int pipe) struct usb_host_endpoint *ep; ep = usb_pipe_endpoint(dev, pipe); - if (usb_pipetype(pipe) != pipetypes[usb_endpoint_type(&ep->desc)]) + if (!ep || usb_pipetype(pipe) != pipetypes[usb_endpoint_type(&ep->desc)]) return -EINVAL; return 0; } -- 2.45.2

2 weeks

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[PATCH 0/2 4.19.y] ALSA: usb-audio: sanity checks for pipes

by Dan Carpenter

Backporting the sanity checks on pipes seems like a good idea. These are basically the same as Takashi Iwai's patches upstream. The difference is that upstream added two sanity checks to code that doesn't exist in 4.19. I had talked about backporting fcc2cc1f3561 ("USB: move snd_usb_pipe_sanity_check into the USB core") but that's just a refactor and not a bug fix. Hillf Danton (1): ALSA: usb-audio: Fix gpf in snd_usb_pipe_sanity_check Takashi Iwai (1): ALSA: usb-audio: Sanity checks for each pipe and EP types sound/usb/helper.c | 17 +++++++++++++++++ sound/usb/helper.h | 1 + sound/usb/quirks.c | 14 +++++++++++--- 3 files changed, 29 insertions(+), 3 deletions(-) -- 2.45.2

2 weeks

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[PATCH 00/10] (no cover subject)

by Vikram Sharma

SC7280 is a Qualcomm SoC. This series adds support to bring up the CSIPHY, CSID, VFE/RDI interfaces in SC7280. SC7280 provides - 3 x VFE, 3 RDI per VFE - 2 x VFE Lite, 4 RDI per VFE - 3 x CSID - 2 x CSID Lite - 5 x CSI PHY The changes are verified on SC7280 qcs6490-rb3gen2-vision board, the base dts for qcs6490-rb3gen2 is: https://lore.kernel.org/all/20231103184655.23555-1-quic_kbajaj@quicinc.com/ V1 for this series: https://lore.kernel.org/linux-arm-msm/20240629-camss_first_post_linux_next-… Changes in V2: 1) Improved indentation/formatting. 2) Removed _src clocks and misleading code comments. 3) Added name fields for power domains and csid register offset in DTSI. 4) Dropped minItems field from YAML file. 5) Listed changes in alphabetical order. 6) Updated description and commit text to reflect changes 7) Changed the compatible string from imx412 to imx577. 8) Added board-specific enablement changes in the newly created vision board DTSI file. 9) Fixed bug encountered during testing. 10) Moved logically independent changes to a new/seprate patch. 11) Removed cci0 as no sensor is on this port and MCLK2, which was a copy-paste error from the RB5 board reference. 12) Added power rails, referencing the RB5 board. 13) Discarded Patch 5/6 completely (not required). 14) Removed unused enums. To: Robert Foss <rfoss(a)kernel.org> To: Todor Tomov <todor.too(a)gmail.com> To: Bryan O'Donoghue <bryan.odonoghue(a)linaro.org> To: Mauro Carvalho Chehab <mchehab(a)kernel.org> To: Rob Herring <robh(a)kernel.org> To: Krzysztof Kozlowski <krzk+dt(a)kernel.org> To: Conor Dooley <conor+dt(a)kernel.org> To: Kapatrala Syed <akapatra(a)quicinc.com> To: Hariram Purushothaman <hariramp(a)quicinc.com> To: Bjorn Andersson <andersson(a)kernel.org> To: Konrad Dybcio <konradybcio(a)kernel.org> To: Hans Verkuil <hverkuil-cisco(a)xs4all.nl> To: cros-qcom-dts-watchers(a)chromium.org To: Catalin Marinas <catalin.marinas(a)arm.com> To: Will Deacon <will(a)kernel.org> Cc: linux-arm-msm(a)vger.kernel.org Cc: linux-media(a)vger.kernel.org Cc: devicetree(a)vger.kernel.org Cc: linux-kernel(a)vger.kernel.org Cc: linux-arm-kernel(a)lists.infradead.org Test-by: Vikram Sharma <quic_vikramsa(a)quicinc.com> Signed-off-by: Vikram Sharma <quic_vikramsa(a)quicinc.com> --- Suresh Vankadara (1): media: qcom: camss: Add support for camss driver on SC7280 Vikram Sharma (9): media: dt-bindings: media: camss: Add qcom,sc7280-camss binding media: dt-bindings: media: qcs6490-rb3gen2-vision-mezzanine: Add dt bindings media: qcom: camss: Fix potential crash if domain attach fails media: qcom: camss: Sort CAMSS version enums and compatible strings media: qcom: camss: Add camss_link_entities_v2 arm64: dts: qcom: sc7280: Add support for camss arm64: dts: qcom: qcs6490-rb3gen2-vision-mezzanine: Enable IMX577 sensor arm64: dts: qcom: sc7280: Add default and suspend states for GPIO arm64: defconfig: Enable camcc driver for SC7280 Documentation/devicetree/bindings/arm/qcom.yaml | 1 + .../bindings/media/qcom,sc7280-camss.yaml | 441 +++++++++++++++++++++ arch/arm64/boot/dts/qcom/Makefile | 1 + .../dts/qcom/qcs6490-rb3gen2-vision-mezzanine.dts | 61 +++ arch/arm64/boot/dts/qcom/sc7280.dtsi | 208 ++++++++++ arch/arm64/configs/defconfig | 1 + drivers/media/platform/qcom/camss/camss-csid.c | 1 - .../platform/qcom/camss/camss-csiphy-3ph-1-0.c | 13 +- drivers/media/platform/qcom/camss/camss-csiphy.c | 5 + drivers/media/platform/qcom/camss/camss-csiphy.h | 1 + drivers/media/platform/qcom/camss/camss-vfe.c | 8 +- drivers/media/platform/qcom/camss/camss.c | 400 ++++++++++++++++++- drivers/media/platform/qcom/camss/camss.h | 1 + 13 files changed, 1131 insertions(+), 11 deletions(-) --- base-commit: fdadd93817f124fd0ea6ef251d4a1068b7feceba change-id: 20240904-camss_on_sc7280_rb3gen2_vision_v2_patches-15c195fb3f12 Best regards, -- Vikram Sharma <quic_vikramsa(a)quicinc.com>

2 weeks

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[PATCH 6.6 0/1] pm, restore async device resume optimization

by Yenchia Chen

We have met a deadlock issue on our device which use 5.15.y when resuming. After applying this patch which is picked from mainline, issue solved. Backport to 6.6.y also. Rafael J. Wysocki (1): PM: sleep: Restore asynchronous device resume optimization drivers/base/power/main.c | 117 +++++++++++++++++++++----------------- include/linux/pm.h | 1 + 2 files changed, 65 insertions(+), 53 deletions(-) -- 2.18.0

2 weeks

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[PATCH 6/8] serial: qcom-geni: fix console corruption

by Johan Hovold

The Qualcomm serial console implementation is broken and can lose characters when the serial port is also used for tty output. Specifically, the console code only waits for the current tx command to complete when all data has already been written to the fifo. When there are on-going longer transfers this often means that console output is lost when the console code inadvertently "hijacks" the current tx command instead of starting a new one. This can, for example, be observed during boot when console output that should have been interspersed with init output is truncated: [ 9.462317] qcom-snps-eusb2-hsphy fde000.phy: Registered Qcom-eUSB2 phy [ OK ] Found device KBG50ZNS256G KIOXIA Wi[ 9.471743ndows. [ 9.539915] xhci-hcd xhci-hcd.0.auto: xHCI Host Controller Add a new state variable to track how much data has been written to the fifo and use it to determine when the fifo and shift register are both empty. This is needed since there is currently no other known way to determine when the shift register is empty. This in turn allows the console code to interrupt long transfers without losing data. Note that the oops-in-progress case is similarly broken as it does not cancel any active command and also waits for the wrong status flag when attempting to drain the fifo (TX_FIFO_NOT_EMPTY_EN is only set when cancelling a command leaves data in the fifo). Fixes: c4f528795d1a ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP") Fixes: a1fee899e5be ("tty: serial: qcom_geni_serial: Fix softlock") Fixes: 9e957a155005 ("serial: qcom-geni: Don't cancel/abort if we can't get the port lock") Cc: stable(a)vger.kernel.org # 4.17 Signed-off-by: Johan Hovold <johan+linaro(a)kernel.org> --- drivers/tty/serial/qcom_geni_serial.c | 48 ++++++++++++++------------- 1 file changed, 25 insertions(+), 23 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index 7029c39a9a21..be620c5703f5 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -131,6 +131,7 @@ struct qcom_geni_serial_port { bool brk; unsigned int tx_remaining; + unsigned int tx_queued; int wakeup_irq; bool rx_tx_swap; bool cts_rts_swap; @@ -144,6 +145,8 @@ static const struct uart_ops qcom_geni_uart_pops; static struct uart_driver qcom_geni_console_driver; static struct uart_driver qcom_geni_uart_driver; +static void qcom_geni_serial_cancel_tx_cmd(struct uart_port *uport); + static inline struct qcom_geni_serial_port *to_dev_port(struct uart_port *uport) { return container_of(uport, struct qcom_geni_serial_port, uport); @@ -308,6 +311,17 @@ static bool qcom_geni_serial_poll_bit(struct uart_port *uport, return qcom_geni_serial_poll_bitfield(uport, offset, field, set ? field : 0); } +static void qcom_geni_serial_drain_fifo(struct uart_port *uport) +{ + struct qcom_geni_serial_port *port = to_dev_port(uport); + + if (!qcom_geni_serial_main_active(uport)) + return; + + qcom_geni_serial_poll_bitfield(uport, SE_GENI_M_GP_LENGTH, GP_LENGTH, + port->tx_queued); +} + static void qcom_geni_serial_setup_tx(struct uart_port *uport, u32 xmit_size) { u32 m_cmd; @@ -476,7 +490,6 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, struct qcom_geni_serial_port *port; bool locked = true; unsigned long flags; - u32 geni_status; WARN_ON(co->index < 0 || co->index >= GENI_UART_CONS_PORTS); @@ -490,34 +503,20 @@ static void qcom_geni_serial_console_write(struct console *co, const char *s, else uart_port_lock_irqsave(uport, &flags); - geni_status = readl(uport->membase + SE_GENI_STATUS); + if (qcom_geni_serial_main_active(uport)) { + /* Wait for completion or drain FIFO */ + if (!locked || port->tx_remaining == 0) + qcom_geni_serial_poll_tx_done(uport); + else + qcom_geni_serial_drain_fifo(uport); - if (!locked) { - /* - * We can only get here if an oops is in progress then we were - * unable to get the lock. This means we can't safely access - * our state variables like tx_remaining. About the best we - * can do is wait for the FIFO to be empty before we start our - * transfer, so we'll do that. - */ - qcom_geni_serial_poll_bit(uport, SE_GENI_M_IRQ_STATUS, - M_TX_FIFO_NOT_EMPTY_EN, false); - } else if ((geni_status & M_GENI_CMD_ACTIVE) && !port->tx_remaining) { - /* - * It seems we can't interrupt existing transfers if all data - * has been sent, in which case we need to look for done first. - */ - qcom_geni_serial_poll_tx_done(uport); + qcom_geni_serial_cancel_tx_cmd(uport); } __qcom_geni_serial_console_write(uport, s, count); - - if (locked) { - if (port->tx_remaining) - qcom_geni_serial_setup_tx(uport, port->tx_remaining); + if (locked) uart_port_unlock_irqrestore(uport, flags); - } } static void handle_rx_console(struct uart_port *uport, u32 bytes, bool drop) @@ -698,6 +697,7 @@ static void qcom_geni_serial_cancel_tx_cmd(struct uart_port *uport) writel(M_CMD_CANCEL_EN, uport->membase + SE_GENI_M_IRQ_CLEAR); port->tx_remaining = 0; + port->tx_queued = 0; } static void qcom_geni_serial_handle_rx_fifo(struct uart_port *uport, bool drop) @@ -924,6 +924,7 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, if (!port->tx_remaining) { qcom_geni_serial_setup_tx(uport, pending); port->tx_remaining = pending; + port->tx_queued = 0; irq_en = readl(uport->membase + SE_GENI_M_IRQ_EN); if (!(irq_en & M_TX_FIFO_WATERMARK_EN)) @@ -932,6 +933,7 @@ static void qcom_geni_serial_handle_tx_fifo(struct uart_port *uport, } qcom_geni_serial_send_chunk_fifo(uport, chunk); + port->tx_queued += chunk; /* * The tx fifo watermark is level triggered and latched. Though we had -- 2.44.2

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Linux-stable-mirror September 2024