HID: bpf: add first in-tree HID-BPF fix for the XPPen Artist 24
This commit adds a fix for XPPen Artist 24 where the second button on the pen is used as an eraser. It's a "feature" from Microsoft, but it turns out that it's actually painful for artists. So we ship here a HID-BPF program that turns this second button into an actual button. Note that the HID-BPF program is not directly loaded by the kernel itself but by udev-hid-bpf[0]. But having the sources here allows us to also integrate tests into tools/testing/selftests/hid to ensure the HID-BPF program are actually tested. [0] https://gitlab.freedesktop.org/libevdev/udev-hid-bpf Link: https://lore.kernel.org/r/20240410-bpf_sources-v1-2-a8bf16033ef8@kernel.org Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net> Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
This commit is contained in:
Benjamin Tissoires
parent
65ad580a14
commit
04b3e5ab05
91
drivers/hid/bpf/progs/Makefile
Normal file
91
drivers/hid/bpf/progs/Makefile
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@ -0,0 +1,91 @@
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# SPDX-License-Identifier: GPL-2.0
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OUTPUT := .output
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abs_out := $(abspath $(OUTPUT))
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CLANG ?= clang
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LLC ?= llc
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LLVM_STRIP ?= llvm-strip
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TOOLS_PATH := $(abspath ../../../../tools)
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BPFTOOL_SRC := $(TOOLS_PATH)/bpf/bpftool
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BPFTOOL_OUTPUT := $(abs_out)/bpftool
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DEFAULT_BPFTOOL := $(BPFTOOL_OUTPUT)/bootstrap/bpftool
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BPFTOOL ?= $(DEFAULT_BPFTOOL)
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LIBBPF_SRC := $(TOOLS_PATH)/lib/bpf
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LIBBPF_OUTPUT := $(abs_out)/libbpf
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LIBBPF_DESTDIR := $(LIBBPF_OUTPUT)
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LIBBPF_INCLUDE := $(LIBBPF_DESTDIR)/include
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BPFOBJ := $(LIBBPF_OUTPUT)/libbpf.a
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INCLUDES := -I$(OUTPUT) -I$(LIBBPF_INCLUDE) -I$(TOOLS_PATH)/include/uapi
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CFLAGS := -g -Wall
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VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \
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$(if $(KBUILD_OUTPUT),$(KBUILD_OUTPUT)/vmlinux) \
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../../../../vmlinux \
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/sys/kernel/btf/vmlinux \
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/boot/vmlinux-$(shell uname -r)
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VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS))))
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ifeq ($(VMLINUX_BTF),)
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$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)")
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endif
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ifeq ($(V),1)
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Q =
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msg =
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else
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Q = @
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msg = @printf ' %-8s %s%s\n' "$(1)" "$(notdir $(2))" "$(if $(3), $(3))";
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MAKEFLAGS += --no-print-directory
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submake_extras := feature_display=0
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endif
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.DELETE_ON_ERROR:
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.PHONY: all clean
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SOURCES = $(wildcard *.bpf.c)
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TARGETS = $(SOURCES:.bpf.c=.bpf.o)
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all: $(TARGETS)
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clean:
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$(call msg,CLEAN)
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$(Q)rm -rf $(OUTPUT) $(TARGETS)
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%.bpf.o: %.bpf.c vmlinux.h $(BPFOBJ) | $(OUTPUT)
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$(call msg,BPF,$@)
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$(Q)$(CLANG) -g -O2 --target=bpf $(INCLUDES) \
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-c $(filter %.c,$^) -o $@ && \
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$(LLVM_STRIP) -g $@
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vmlinux.h: $(VMLINUX_BTF) $(BPFTOOL) | $(INCLUDE_DIR)
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ifeq ($(VMLINUX_H),)
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$(call msg,GEN,,$@)
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$(Q)$(BPFTOOL) btf dump file $(VMLINUX_BTF) format c > $@
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else
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$(call msg,CP,,$@)
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$(Q)cp "$(VMLINUX_H)" $@
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endif
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$(OUTPUT) $(LIBBPF_OUTPUT) $(BPFTOOL_OUTPUT):
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$(call msg,MKDIR,$@)
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$(Q)mkdir -p $@
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$(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OUTPUT)
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$(Q)$(MAKE) $(submake_extras) -C $(LIBBPF_SRC) \
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OUTPUT=$(abspath $(dir $@))/ prefix= \
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DESTDIR=$(LIBBPF_DESTDIR) $(abspath $@) install_headers
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ifeq ($(CROSS_COMPILE),)
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$(DEFAULT_BPFTOOL): $(BPFOBJ) | $(BPFTOOL_OUTPUT)
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$(Q)$(MAKE) $(submake_extras) -C $(BPFTOOL_SRC) \
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OUTPUT=$(BPFTOOL_OUTPUT)/ \
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LIBBPF_BOOTSTRAP_OUTPUT=$(LIBBPF_OUTPUT)/ \
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LIBBPF_BOOTSTRAP_DESTDIR=$(LIBBPF_DESTDIR)/ bootstrap
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else
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$(DEFAULT_BPFTOOL): | $(BPFTOOL_OUTPUT)
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$(Q)$(MAKE) $(submake_extras) -C $(BPFTOOL_SRC) \
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OUTPUT=$(BPFTOOL_OUTPUT)/ bootstrap
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endif
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102
drivers/hid/bpf/progs/README
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102
drivers/hid/bpf/progs/README
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@ -0,0 +1,102 @@
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# HID-BPF programs
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This directory contains various fixes for devices. They add new features or
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fix some behaviors without being entirely mandatory. It is better to load them
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when you have such a device, but they should not be a requirement for a device
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to be working during the boot stage.
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The .bpf.c files provided here are not automatically compiled in the kernel.
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They should be loaded in the kernel by `udev-hid-bpf`:
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https://gitlab.freedesktop.org/libevdev/udev-hid-bpf
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The main reasons for these fixes to be here is to have a central place to
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"upstream" them, but also this way we can test them thanks to the HID
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selftests.
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Once a .bpf.c file is accepted here, it is duplicated in `udev-hid-bpf`
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in the `src/bpf/stable` directory, and distributions are encouraged to
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only ship those bpf objects. So adding a file here should eventually
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land in distributions when they update `udev-hid-bpf`
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## Compilation
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Just run `make`
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## Installation
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### Automated way
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Just run `sudo udev-hid-bpf install ./my-awesome-fix.bpf.o`
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### Manual way
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- copy the `.bpf.o` you want in `/etc/udev-hid-bpf/`
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- create a new udev rule to automatically load it
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The following should do the trick (assuming udev-hid-bpf is available in
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/usr/bin):
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```
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$> cp xppen-ArtistPro16Gen2.bpf.o /etc/udev-hid-bpf/
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$> udev-hid-bpf inspect xppen-ArtistPro16Gen2.bpf.o
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[
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{
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"name": "xppen-ArtistPro16Gen2.bpf.o",
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"devices": [
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{
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"bus": "0x0003",
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"group": "0x0001",
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"vid": "0x28BD",
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"pid": "0x095A"
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},
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{
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"bus": "0x0003",
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"group": "0x0001",
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"vid": "0x28BD",
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"pid": "0x095B"
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}
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],
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...
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$> cat <EOF > /etc/udev/rules.d/99-load-hid-bpf-xppen-ArtistPro16Gen2.rules
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ACTION!="add|remove", GOTO="hid_bpf_end"
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SUBSYSTEM!="hid", GOTO="hid_bpf_end"
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# xppen-ArtistPro16Gen2.bpf.o
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ACTION=="add",ENV{MODALIAS}=="hid:b0003g0001v000028BDp0000095A", RUN{program}+="/usr/local/bin/udev-hid-bpf add $sys$devpath /etc/udev-hid-bpf/xppen-ArtistPro16Gen2.bpf.o"
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ACTION=="remove",ENV{MODALIAS}=="hid:b0003g0001v000028BDp0000095A", RUN{program}+="/usr/local/bin/udev-hid-bpf remove $sys$devpath "
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# xppen-ArtistPro16Gen2.bpf.o
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ACTION=="add",ENV{MODALIAS}=="hid:b0003g0001v000028BDp0000095B", RUN{program}+="/usr/local/bin/udev-hid-bpf add $sys$devpath /etc/udev-hid-bpf/xppen-ArtistPro16Gen2.bpf.o"
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ACTION=="remove",ENV{MODALIAS}=="hid:b0003g0001v000028BDp0000095B", RUN{program}+="/usr/local/bin/udev-hid-bpf remove $sys$devpath "
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LABEL="hid_bpf_end"
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EOF
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$> udevadm control --reload
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```
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Then unplug and replug the device.
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## Checks
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### udev rule
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You can check that the udev rule is correctly working by issuing
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```
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$> udevadm test /sys/bus/hid/devices/0003:28BD:095B*
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...
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run: '/usr/local/bin/udev-hid-bpf add /sys/devices/virtual/misc/uhid/0003:28BD:095B.0E57 /etc/udev-hid-bpf/xppen-ArtistPro16Gen2.bpf.o'
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```
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### program loaded
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You can check that the program has been properly loaded with `bpftool`
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```
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$> bpftool prog
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...
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247: tracing name xppen_16_fix_eraser tag 18d389353ed2ef07 gpl
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loaded_at 2024-03-28T16:02:28+0100 uid 0
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xlated 120B jited 77B memlock 4096B
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btf_id 487
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```
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229
drivers/hid/bpf/progs/XPPen__Artist24.bpf.c
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229
drivers/hid/bpf/progs/XPPen__Artist24.bpf.c
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@ -0,0 +1,229 @@
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// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2023 Benjamin Tissoires
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*/
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#include "vmlinux.h"
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#include "hid_bpf.h"
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#include "hid_bpf_helpers.h"
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#include <bpf/bpf_tracing.h>
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#define VID_UGEE 0x28BD /* VID is shared with SinoWealth and Glorious and prob others */
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#define PID_ARTIST_24 0x093A
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#define PID_ARTIST_24_PRO 0x092D
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HID_BPF_CONFIG(
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HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_UGEE, PID_ARTIST_24),
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HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_UGEE, PID_ARTIST_24_PRO)
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);
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/*
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* We need to amend the report descriptor for the following:
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* - the device reports Eraser instead of using Secondary Barrel Switch
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* - the pen doesn't have a rubber tail, so basically we are removing any
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* eraser/invert bits
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*/
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static const __u8 fixed_rdesc[] = {
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0x05, 0x0d, // Usage Page (Digitizers) 0
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0x09, 0x02, // Usage (Pen) 2
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0xa1, 0x01, // Collection (Application) 4
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0x85, 0x07, // Report ID (7) 6
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0x09, 0x20, // Usage (Stylus) 8
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0xa1, 0x00, // Collection (Physical) 10
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0x09, 0x42, // Usage (Tip Switch) 12
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0x09, 0x44, // Usage (Barrel Switch) 14
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0x09, 0x5a, // Usage (Secondary Barrel Switch) 16 /* changed from 0x45 (Eraser) to 0x5a (Secondary Barrel Switch) */
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0x15, 0x00, // Logical Minimum (0) 18
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0x25, 0x01, // Logical Maximum (1) 20
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0x75, 0x01, // Report Size (1) 22
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0x95, 0x03, // Report Count (3) 24
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0x81, 0x02, // Input (Data,Var,Abs) 26
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0x95, 0x02, // Report Count (2) 28
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0x81, 0x03, // Input (Cnst,Var,Abs) 30
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0x09, 0x32, // Usage (In Range) 32
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0x95, 0x01, // Report Count (1) 34
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0x81, 0x02, // Input (Data,Var,Abs) 36
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0x95, 0x02, // Report Count (2) 38
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0x81, 0x03, // Input (Cnst,Var,Abs) 40
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0x75, 0x10, // Report Size (16) 42
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0x95, 0x01, // Report Count (1) 44
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0x35, 0x00, // Physical Minimum (0) 46
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0xa4, // Push 48
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0x05, 0x01, // Usage Page (Generic Desktop) 49
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0x09, 0x30, // Usage (X) 51
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0x65, 0x13, // Unit (EnglishLinear: in) 53
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0x55, 0x0d, // Unit Exponent (-3) 55
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0x46, 0xf0, 0x50, // Physical Maximum (20720) 57
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0x26, 0xff, 0x7f, // Logical Maximum (32767) 60
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0x81, 0x02, // Input (Data,Var,Abs) 63
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0x09, 0x31, // Usage (Y) 65
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0x46, 0x91, 0x2d, // Physical Maximum (11665) 67
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0x26, 0xff, 0x7f, // Logical Maximum (32767) 70
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0x81, 0x02, // Input (Data,Var,Abs) 73
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0xb4, // Pop 75
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0x09, 0x30, // Usage (Tip Pressure) 76
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0x45, 0x00, // Physical Maximum (0) 78
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0x26, 0xff, 0x1f, // Logical Maximum (8191) 80
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0x81, 0x42, // Input (Data,Var,Abs,Null) 83
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0x09, 0x3d, // Usage (X Tilt) 85
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0x15, 0x81, // Logical Minimum (-127) 87
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0x25, 0x7f, // Logical Maximum (127) 89
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0x75, 0x08, // Report Size (8) 91
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0x95, 0x01, // Report Count (1) 93
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0x81, 0x02, // Input (Data,Var,Abs) 95
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0x09, 0x3e, // Usage (Y Tilt) 97
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0x15, 0x81, // Logical Minimum (-127) 99
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0x25, 0x7f, // Logical Maximum (127) 101
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0x81, 0x02, // Input (Data,Var,Abs) 103
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0xc0, // End Collection 105
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0xc0, // End Collection 106
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};
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#define BIT(n) (1UL << n)
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#define TIP_SWITCH BIT(0)
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#define BARREL_SWITCH BIT(1)
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#define ERASER BIT(2)
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/* padding BIT(3) */
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/* padding BIT(4) */
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#define IN_RANGE BIT(5)
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/* padding BIT(6) */
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/* padding BIT(7) */
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#define U16(index) (data[index] | (data[index + 1] << 8))
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SEC("fmod_ret/hid_bpf_rdesc_fixup")
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int BPF_PROG(hid_fix_rdesc_xppen_artist24, struct hid_bpf_ctx *hctx)
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{
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__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */);
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if (!data)
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return 0; /* EPERM check */
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__builtin_memcpy(data, fixed_rdesc, sizeof(fixed_rdesc));
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return sizeof(fixed_rdesc);
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}
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static __u8 prev_state = 0;
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/*
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* There are a few cases where the device is sending wrong event
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* sequences, all related to the second button (the pen doesn't
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* have an eraser switch on the tail end):
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*
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* whenever the second button gets pressed or released, an
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* out-of-proximity event is generated and then the firmware
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* compensate for the missing state (and the firmware uses
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* eraser for that button):
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*
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* - if the pen is in range, an extra out-of-range is sent
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* when the second button is pressed/released:
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* // Pen is in range
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* E: InRange
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*
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* // Second button is pressed
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* E:
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* E: Eraser InRange
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*
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* // Second button is released
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* E:
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* E: InRange
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*
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* This case is ignored by this filter, it's "valid"
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* and userspace knows how to deal with it, there are just
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* a few out-of-prox events generated, but the user doesn´t
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* see them.
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*
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* - if the pen is in contact, 2 extra events are added when
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* the second button is pressed/released: an out of range
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* and an in range:
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*
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* // Pen is in contact
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* E: TipSwitch InRange
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*
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* // Second button is pressed
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* E: <- false release, needs to be filtered out
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* E: Eraser InRange <- false release, needs to be filtered out
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* E: TipSwitch Eraser InRange
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*
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* // Second button is released
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* E: <- false release, needs to be filtered out
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* E: InRange <- false release, needs to be filtered out
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* E: TipSwitch InRange
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*
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*/
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SEC("fmod_ret/hid_bpf_device_event")
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int BPF_PROG(xppen_24_fix_eraser, struct hid_bpf_ctx *hctx)
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{
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__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 10 /* size */);
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__u8 current_state, changed_state;
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bool prev_tip;
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__u16 tilt;
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if (!data)
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return 0; /* EPERM check */
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current_state = data[1];
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/* if the state is identical to previously, early return */
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if (current_state == prev_state)
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return 0;
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prev_tip = !!(prev_state & TIP_SWITCH);
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/*
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* Illegal transition: pen is in range with the tip pressed, and
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* it goes into out of proximity.
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*
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* Ideally we should hold the event, start a timer and deliver it
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* only if the timer ends, but we are not capable of that now.
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*
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* And it doesn't matter because when we are in such cases, this
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* means we are detecting a false release.
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*/
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if ((current_state & IN_RANGE) == 0) {
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if (prev_tip)
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return HID_IGNORE_EVENT;
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return 0;
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}
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/*
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* XOR to only set the bits that have changed between
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* previous and current state
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*/
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changed_state = prev_state ^ current_state;
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/* Store the new state for future processing */
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prev_state = current_state;
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/*
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* We get both a tipswitch and eraser change in the same HID report:
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* this is not an authorized transition and is unlikely to happen
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* in real life.
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* This is likely to be added by the firmware to emulate the
|
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* eraser mode so we can skip the event.
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*/
|
||||
if ((changed_state & (TIP_SWITCH | ERASER)) == (TIP_SWITCH | ERASER)) /* we get both a tipswitch and eraser change at the same time */
|
||||
return HID_IGNORE_EVENT;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
SEC("syscall")
|
||||
int probe(struct hid_bpf_probe_args *ctx)
|
||||
{
|
||||
/*
|
||||
* The device exports 3 interfaces.
|
||||
*/
|
||||
ctx->retval = ctx->rdesc_size != 107;
|
||||
if (ctx->retval)
|
||||
ctx->retval = -EINVAL;
|
||||
|
||||
/* ensure the kernel isn't fixed already */
|
||||
if (ctx->rdesc[17] != 0x45) /* Eraser */
|
||||
ctx->retval = -EINVAL;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
char _license[] SEC("license") = "GPL";
|
||||
15
drivers/hid/bpf/progs/hid_bpf.h
Normal file
15
drivers/hid/bpf/progs/hid_bpf.h
Normal file
@ -0,0 +1,15 @@
|
||||
/* SPDX-License-Identifier: GPL-2.0-only */
|
||||
/* Copyright (c) 2022 Benjamin Tissoires
|
||||
*/
|
||||
|
||||
#ifndef ____HID_BPF__H
|
||||
#define ____HID_BPF__H
|
||||
|
||||
struct hid_bpf_probe_args {
|
||||
unsigned int hid;
|
||||
unsigned int rdesc_size;
|
||||
unsigned char rdesc[4096];
|
||||
int retval;
|
||||
};
|
||||
|
||||
#endif /* ____HID_BPF__H */
|
||||
168
drivers/hid/bpf/progs/hid_bpf_helpers.h
Normal file
168
drivers/hid/bpf/progs/hid_bpf_helpers.h
Normal file
@ -0,0 +1,168 @@
|
||||
/* SPDX-License-Identifier: GPL-2.0-only */
|
||||
/* Copyright (c) 2022 Benjamin Tissoires
|
||||
*/
|
||||
|
||||
#ifndef __HID_BPF_HELPERS_H
|
||||
#define __HID_BPF_HELPERS_H
|
||||
|
||||
#include "vmlinux.h"
|
||||
#include <bpf/bpf_helpers.h>
|
||||
#include <linux/errno.h>
|
||||
|
||||
extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx,
|
||||
unsigned int offset,
|
||||
const size_t __sz) __ksym;
|
||||
extern struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __ksym;
|
||||
extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __ksym;
|
||||
extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx,
|
||||
__u8 *data,
|
||||
size_t buf__sz,
|
||||
enum hid_report_type type,
|
||||
enum hid_class_request reqtype) __ksym;
|
||||
|
||||
#define HID_MAX_DESCRIPTOR_SIZE 4096
|
||||
#define HID_IGNORE_EVENT -1
|
||||
|
||||
/* extracted from <linux/input.h> */
|
||||
#define BUS_ANY 0x00
|
||||
#define BUS_PCI 0x01
|
||||
#define BUS_ISAPNP 0x02
|
||||
#define BUS_USB 0x03
|
||||
#define BUS_HIL 0x04
|
||||
#define BUS_BLUETOOTH 0x05
|
||||
#define BUS_VIRTUAL 0x06
|
||||
#define BUS_ISA 0x10
|
||||
#define BUS_I8042 0x11
|
||||
#define BUS_XTKBD 0x12
|
||||
#define BUS_RS232 0x13
|
||||
#define BUS_GAMEPORT 0x14
|
||||
#define BUS_PARPORT 0x15
|
||||
#define BUS_AMIGA 0x16
|
||||
#define BUS_ADB 0x17
|
||||
#define BUS_I2C 0x18
|
||||
#define BUS_HOST 0x19
|
||||
#define BUS_GSC 0x1A
|
||||
#define BUS_ATARI 0x1B
|
||||
#define BUS_SPI 0x1C
|
||||
#define BUS_RMI 0x1D
|
||||
#define BUS_CEC 0x1E
|
||||
#define BUS_INTEL_ISHTP 0x1F
|
||||
#define BUS_AMD_SFH 0x20
|
||||
|
||||
/* extracted from <linux/hid.h> */
|
||||
#define HID_GROUP_ANY 0x0000
|
||||
#define HID_GROUP_GENERIC 0x0001
|
||||
#define HID_GROUP_MULTITOUCH 0x0002
|
||||
#define HID_GROUP_SENSOR_HUB 0x0003
|
||||
#define HID_GROUP_MULTITOUCH_WIN_8 0x0004
|
||||
#define HID_GROUP_RMI 0x0100
|
||||
#define HID_GROUP_WACOM 0x0101
|
||||
#define HID_GROUP_LOGITECH_DJ_DEVICE 0x0102
|
||||
#define HID_GROUP_STEAM 0x0103
|
||||
#define HID_GROUP_LOGITECH_27MHZ_DEVICE 0x0104
|
||||
#define HID_GROUP_VIVALDI 0x0105
|
||||
|
||||
/* include/linux/mod_devicetable.h defines as (~0), but that gives us negative size arrays */
|
||||
#define HID_VID_ANY 0x0000
|
||||
#define HID_PID_ANY 0x0000
|
||||
|
||||
#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
|
||||
|
||||
/* Helper macro to convert (foo, __LINE__) into foo134 so we can use __LINE__ for
|
||||
* field/variable names
|
||||
*/
|
||||
#define COMBINE1(X, Y) X ## Y
|
||||
#define COMBINE(X, Y) COMBINE1(X, Y)
|
||||
|
||||
/* Macro magic:
|
||||
* __uint(foo, 123) creates a int (*foo)[1234]
|
||||
*
|
||||
* We use that macro to declare an anonymous struct with several
|
||||
* fields, each is the declaration of an pointer to an array of size
|
||||
* bus/group/vid/pid. (Because it's a pointer to such an array, actual storage
|
||||
* would be sizeof(pointer) rather than sizeof(array). Not that we ever
|
||||
* instantiate it anyway).
|
||||
*
|
||||
* This is only used for BTF introspection, we can later check "what size
|
||||
* is the bus array" in the introspection data and thus extract the bus ID
|
||||
* again.
|
||||
*
|
||||
* And we use the __LINE__ to give each of our structs a unique name so the
|
||||
* BPF program writer doesn't have to.
|
||||
*
|
||||
* $ bpftool btf dump file target/bpf/HP_Elite_Presenter.bpf.o
|
||||
* shows the inspection data, start by searching for .hid_bpf_config
|
||||
* and working backwards from that (each entry references the type_id of the
|
||||
* content).
|
||||
*/
|
||||
|
||||
#define HID_DEVICE(b, g, ven, prod) \
|
||||
struct { \
|
||||
__uint(name, 0); \
|
||||
__uint(bus, (b)); \
|
||||
__uint(group, (g)); \
|
||||
__uint(vid, (ven)); \
|
||||
__uint(pid, (prod)); \
|
||||
} COMBINE(_entry, __LINE__)
|
||||
|
||||
/* Macro magic below is to make HID_BPF_CONFIG() look like a function call that
|
||||
* we can pass multiple HID_DEVICE() invocations in.
|
||||
*
|
||||
* For up to 16 arguments, HID_BPF_CONFIG(one, two) resolves to
|
||||
*
|
||||
* union {
|
||||
* HID_DEVICE(...);
|
||||
* HID_DEVICE(...);
|
||||
* } _device_ids SEC(".hid_bpf_config")
|
||||
*
|
||||
*/
|
||||
|
||||
/* Returns the number of macro arguments, this expands
|
||||
* NARGS(a, b, c) to NTH_ARG(a, b, c, 15, 14, 13, .... 4, 3, 2, 1).
|
||||
* NTH_ARG always returns the 16th argument which in our case is 3.
|
||||
*
|
||||
* If we want more than 16 values _COUNTDOWN and _NTH_ARG both need to be
|
||||
* updated.
|
||||
*/
|
||||
#define _NARGS(...) _NARGS1(__VA_ARGS__, _COUNTDOWN)
|
||||
#define _NARGS1(...) _NTH_ARG(__VA_ARGS__)
|
||||
|
||||
/* Add to this if we need more than 16 args */
|
||||
#define _COUNTDOWN \
|
||||
15, 14, 13, 12, 11, 10, 9, 8, \
|
||||
7, 6, 5, 4, 3, 2, 1, 0
|
||||
|
||||
/* Return the 16 argument passed in. See _NARGS above for usage. Note this is
|
||||
* 1-indexed.
|
||||
*/
|
||||
#define _NTH_ARG( \
|
||||
_1, _2, _3, _4, _5, _6, _7, _8, \
|
||||
_9, _10, _11, _12, _13, _14, _15,\
|
||||
N, ...) N
|
||||
|
||||
/* Turns EXPAND(_ARG, a, b, c) into _ARG3(a, b, c) */
|
||||
#define _EXPAND(func, ...) COMBINE(func, _NARGS(__VA_ARGS__)) (__VA_ARGS__)
|
||||
|
||||
/* And now define all the ARG macros for each number of args we want to accept */
|
||||
#define _ARG1(_1) _1;
|
||||
#define _ARG2(_1, _2) _1; _2;
|
||||
#define _ARG3(_1, _2, _3) _1; _2; _3;
|
||||
#define _ARG4(_1, _2, _3, _4) _1; _2; _3; _4;
|
||||
#define _ARG5(_1, _2, _3, _4, _5) _1; _2; _3; _4; _5;
|
||||
#define _ARG6(_1, _2, _3, _4, _5, _6) _1; _2; _3; _4; _5; _6;
|
||||
#define _ARG7(_1, _2, _3, _4, _5, _6, _7) _1; _2; _3; _4; _5; _6; _7;
|
||||
#define _ARG8(_1, _2, _3, _4, _5, _6, _7, _8) _1; _2; _3; _4; _5; _6; _7; _8;
|
||||
#define _ARG9(_1, _2, _3, _4, _5, _6, _7, _8, _9) _1; _2; _3; _4; _5; _6; _7; _8; _9;
|
||||
#define _ARG10(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a;
|
||||
#define _ARG11(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b;
|
||||
#define _ARG12(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; _c;
|
||||
#define _ARG13(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, _d) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; _c; _d;
|
||||
#define _ARG14(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, _d, _e) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; _c; _d; _e;
|
||||
#define _ARG15(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b, _c, _d, _e, _f) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b; _c; _d; _e; _f;
|
||||
|
||||
|
||||
#define HID_BPF_CONFIG(...) union { \
|
||||
_EXPAND(_ARG, __VA_ARGS__) \
|
||||
} _device_ids SEC(".hid_bpf_config")
|
||||
|
||||
#endif /* __HID_BPF_HELPERS_H */
|
||||
Loading…
Reference in New Issue
Block a user