Hi,
here comes the v7 of the HID-BPF series.
Again, for a full explanation of HID-BPF, please refer to the last patch in this series (24/24).
This version sees some minor improvements compared to v6, only focusing on the reviews I got.
I also wanted to mention that I have started working on the userspace side to "see" how the BPF programs would look when automatically loaded. See the udev-hid-bpf project[0] for the code.
The idea is to define the HID-BPF userspace programs so we can reuse the same semantic in the kernel. I am quite happy with the results: this looks pretty similar to a kernel module in term of design. The .bpf.c file is a standalone compilation unit, and instead of having a table of ids, the filename is used (based on the modalias). This allows to have a "probe" like function that we can run to decide if the program needs to be attached or not.
All in all, the end result is that we can write the bpf program, compile it locally, and send the result to the user. The user needs to drop the .bpf.o in a local folder, and udev-hid-bpf will pick it up the next time the device is plugged in. No other operations is required.
Next step will be to drop the same source file in the kernel source tree, and have some magic to automatically load the compiled program when the device is loaded.
Cheers, Benjamin
[0] https://gitlab.freedesktop.org/bentiss/udev-hid-bpf (warning: probably not the best rust code ever)
Benjamin Tissoires (24): selftests/bpf: fix config for CLS_BPF bpf/verifier: allow kfunc to read user provided context bpf/verifier: do not clear meta in check_mem_size selftests/bpf: add test for accessing ctx from syscall program type bpf/verifier: allow kfunc to return an allocated mem selftests/bpf: Add tests for kfunc returning a memory pointer bpf: prepare for more bpf syscall to be used from kernel and user space. libbpf: add map_get_fd_by_id and map_delete_elem in light skeleton HID: core: store the unique system identifier in hid_device HID: export hid_report_type to uapi HID: convert defines of HID class requests into a proper enum HID: Kconfig: split HID support and hid-core compilation HID: initial BPF implementation selftests/bpf: add tests for the HID-bpf initial implementation HID: bpf: allocate data memory for device_event BPF programs selftests/bpf/hid: add test to change the report size HID: bpf: introduce hid_hw_request() selftests/bpf: add tests for bpf_hid_hw_request HID: bpf: allow to change the report descriptor selftests/bpf: add report descriptor fixup tests selftests/bpf: Add a test for BPF_F_INSERT_HEAD samples/bpf: add new hid_mouse example HID: bpf: add Surface Dial example Documentation: add HID-BPF docs
Documentation/hid/hid-bpf.rst | 512 +++++++++ Documentation/hid/index.rst | 1 + drivers/Makefile | 2 +- drivers/hid/Kconfig | 20 +- drivers/hid/Makefile | 2 + drivers/hid/bpf/Kconfig | 18 + drivers/hid/bpf/Makefile | 11 + drivers/hid/bpf/entrypoints/Makefile | 93 ++ drivers/hid/bpf/entrypoints/README | 4 + drivers/hid/bpf/entrypoints/entrypoints.bpf.c | 66 ++ .../hid/bpf/entrypoints/entrypoints.lskel.h | 682 ++++++++++++ drivers/hid/bpf/hid_bpf_dispatch.c | 553 ++++++++++ drivers/hid/bpf/hid_bpf_dispatch.h | 28 + drivers/hid/bpf/hid_bpf_jmp_table.c | 577 ++++++++++ drivers/hid/hid-core.c | 49 +- include/linux/bpf.h | 9 +- include/linux/btf.h | 10 + include/linux/hid.h | 38 +- include/linux/hid_bpf.h | 148 +++ include/uapi/linux/hid.h | 26 +- include/uapi/linux/hid_bpf.h | 25 + kernel/bpf/btf.c | 91 +- kernel/bpf/syscall.c | 10 +- kernel/bpf/verifier.c | 65 +- net/bpf/test_run.c | 23 + samples/bpf/.gitignore | 2 + samples/bpf/Makefile | 27 + samples/bpf/hid_mouse.bpf.c | 134 +++ samples/bpf/hid_mouse.c | 147 +++ samples/bpf/hid_surface_dial.bpf.c | 161 +++ samples/bpf/hid_surface_dial.c | 212 ++++ tools/include/uapi/linux/hid.h | 62 ++ tools/include/uapi/linux/hid_bpf.h | 25 + tools/lib/bpf/skel_internal.h | 23 + tools/testing/selftests/bpf/Makefile | 5 +- tools/testing/selftests/bpf/config | 5 +- tools/testing/selftests/bpf/prog_tests/hid.c | 990 ++++++++++++++++++ .../selftests/bpf/prog_tests/kfunc_call.c | 76 ++ tools/testing/selftests/bpf/progs/hid.c | 206 ++++ .../selftests/bpf/progs/kfunc_call_test.c | 125 +++ 40 files changed, 5184 insertions(+), 79 deletions(-) create mode 100644 Documentation/hid/hid-bpf.rst create mode 100644 drivers/hid/bpf/Kconfig create mode 100644 drivers/hid/bpf/Makefile create mode 100644 drivers/hid/bpf/entrypoints/Makefile create mode 100644 drivers/hid/bpf/entrypoints/README create mode 100644 drivers/hid/bpf/entrypoints/entrypoints.bpf.c create mode 100644 drivers/hid/bpf/entrypoints/entrypoints.lskel.h create mode 100644 drivers/hid/bpf/hid_bpf_dispatch.c create mode 100644 drivers/hid/bpf/hid_bpf_dispatch.h create mode 100644 drivers/hid/bpf/hid_bpf_jmp_table.c create mode 100644 include/linux/hid_bpf.h create mode 100644 include/uapi/linux/hid_bpf.h create mode 100644 samples/bpf/hid_mouse.bpf.c create mode 100644 samples/bpf/hid_mouse.c create mode 100644 samples/bpf/hid_surface_dial.bpf.c create mode 100644 samples/bpf/hid_surface_dial.c create mode 100644 tools/include/uapi/linux/hid.h create mode 100644 tools/include/uapi/linux/hid_bpf.h create mode 100644 tools/testing/selftests/bpf/prog_tests/hid.c create mode 100644 tools/testing/selftests/bpf/progs/hid.c