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 Signed-off-by: Benjamin Tissoires <bentiss@xxxxxxxxxx> --- drivers/hid/bpf/progs/Makefile | 91 +++++++++++ drivers/hid/bpf/progs/README | 102 +++++++++++++ drivers/hid/bpf/progs/XPPen__Artist24.bpf.c | 229 ++++++++++++++++++++++++++++ drivers/hid/bpf/progs/hid_bpf.h | 15 ++ drivers/hid/bpf/progs/hid_bpf_helpers.h | 170 +++++++++++++++++++++ 5 files changed, 607 insertions(+) diff --git a/drivers/hid/bpf/progs/Makefile b/drivers/hid/bpf/progs/Makefile new file mode 100644 index 000000000000..63ed7e02adf1 --- /dev/null +++ b/drivers/hid/bpf/progs/Makefile @@ -0,0 +1,91 @@ +# 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 + +SOURCES = $(wildcard *.bpf.c) +TARGETS = $(SOURCES:.bpf.c=.bpf.o) + +all: $(TARGETS) + +clean: + $(call msg,CLEAN) + $(Q)rm -rf $(OUTPUT) $(TARGETS) + +%.bpf.o: %.bpf.c vmlinux.h $(BPFOBJ) | $(OUTPUT) + $(call msg,BPF,$@) + $(Q)$(CLANG) -g -O2 --target=bpf $(INCLUDES) \ + -c $(filter %.c,$^) -o $@ && \ + $(LLVM_STRIP) -g $@ + +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/progs/README b/drivers/hid/bpf/progs/README new file mode 100644 index 000000000000..20b0928f385b --- /dev/null +++ b/drivers/hid/bpf/progs/README @@ -0,0 +1,102 @@ +# HID-BPF programs + +This directory contains various fixes for devices. They add new features or +fix some behaviors without being entirely mandatory. It is better to load them +when you have such a device, but they should not be a requirement for a device +to be working during the boot stage. + +The .bpf.c files provided here are not automatically compiled in the kernel. +They should be loaded in the kernel by `udev-hid-bpf`: + +https://gitlab.freedesktop.org/libevdev/udev-hid-bpf + +The main reasons for these fixes to be here is to have a central place to +"upstream" them, but also this way we can test them thanks to the HID +selftests. + +Once a .bpf.c file is accepted here, it is duplicated in `udev-hid-bpf` +in the `src/bpf/stable` directory, and distributions are encouraged to +only ship those bpf objects. So adding a file here should eventually +land in distributions when they update `udev-hid-bpf` + +## Compilation + +Just run `make` + +## Installation + +### Automated way + +Just run `sudo udev-hid-bpf install ./my-awesome-fix.bpf.o` + +### Manual way + +- copy the `.bpf.o` you want in `/etc/udev-hid-bpf/` +- create a new udev rule to automatically load it + +The following should do the trick (assuming udev-hid-bpf is available in +/usr/bin): + +``` +$> cp xppen-ArtistPro16Gen2.bpf.o /etc/udev-hid-bpf/ +$> udev-hid-bpf inspect xppen-ArtistPro16Gen2.bpf.o +[ + { + "name": "xppen-ArtistPro16Gen2.bpf.o", + "devices": [ + { + "bus": "0x0003", + "group": "0x0001", + "vid": "0x28BD", + "pid": "0x095A" + }, + { + "bus": "0x0003", + "group": "0x0001", + "vid": "0x28BD", + "pid": "0x095B" + } + ], +... +$> cat <EOF > /etc/udev/rules.d/99-load-hid-bpf-xppen-ArtistPro16Gen2.rules +ACTION!="add|remove", GOTO="hid_bpf_end" +SUBSYSTEM!="hid", GOTO="hid_bpf_end" + +# xppen-ArtistPro16Gen2.bpf.o +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" +ACTION=="remove",ENV{MODALIAS}=="hid:b0003g0001v000028BDp0000095A", RUN{program}+="/usr/local/bin/udev-hid-bpf remove $sys$devpath " +# xppen-ArtistPro16Gen2.bpf.o +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" +ACTION=="remove",ENV{MODALIAS}=="hid:b0003g0001v000028BDp0000095B", RUN{program}+="/usr/local/bin/udev-hid-bpf remove $sys$devpath " + +LABEL="hid_bpf_end" +EOF +$> udevadm control --reload +``` + +Then unplug and replug the device. + +## Checks + +### udev rule + +You can check that the udev rule is correctly working by issuing + +``` +$> udevadm test /sys/bus/hid/devices/0003:28BD:095B* +... +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' +``` + +### program loaded + +You can check that the program has been properly loaded with `bpftool` + +``` +$> bpftool prog +... +247: tracing name xppen_16_fix_eraser tag 18d389353ed2ef07 gpl + loaded_at 2024-03-28T16:02:28+0100 uid 0 + xlated 120B jited 77B memlock 4096B + btf_id 487 +``` diff --git a/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c b/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c new file mode 100644 index 000000000000..e1be6a12bb75 --- /dev/null +++ b/drivers/hid/bpf/progs/XPPen__Artist24.bpf.c @@ -0,0 +1,229 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2023 Benjamin Tissoires + */ + +#include "vmlinux.h" +#include "hid_bpf.h" +#include "hid_bpf_helpers.h" +#include <bpf/bpf_tracing.h> + +#define VID_UGEE 0x28BD /* VID is shared with SinoWealth and Glorious and prob others */ +#define PID_ARTIST_24 0x093A +#define PID_ARTIST_24_PRO 0x092D + +HID_BPF_CONFIG( + HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_UGEE, PID_ARTIST_24), + HID_DEVICE(BUS_USB, HID_GROUP_GENERIC, VID_UGEE, PID_ARTIST_24_PRO) +); + +/* + * We need to amend the report descriptor for the following: + * - the device reports Eraser instead of using Secondary Barrel Switch + * - the pen doesn't have a rubber tail, so basically we are removing any + * eraser/invert bits + */ +static const __u8 fixed_rdesc[] = { + 0x05, 0x0d, // Usage Page (Digitizers) 0 + 0x09, 0x02, // Usage (Pen) 2 + 0xa1, 0x01, // Collection (Application) 4 + 0x85, 0x07, // Report ID (7) 6 + 0x09, 0x20, // Usage (Stylus) 8 + 0xa1, 0x00, // Collection (Physical) 10 + 0x09, 0x42, // Usage (Tip Switch) 12 + 0x09, 0x44, // Usage (Barrel Switch) 14 + 0x09, 0x5a, // Usage (Secondary Barrel Switch) 16 /* changed from 0x45 (Eraser) to 0x5a (Secondary Barrel Switch) */ + 0x15, 0x00, // Logical Minimum (0) 18 + 0x25, 0x01, // Logical Maximum (1) 20 + 0x75, 0x01, // Report Size (1) 22 + 0x95, 0x03, // Report Count (3) 24 + 0x81, 0x02, // Input (Data,Var,Abs) 26 + 0x95, 0x02, // Report Count (2) 28 + 0x81, 0x03, // Input (Cnst,Var,Abs) 30 + 0x09, 0x32, // Usage (In Range) 32 + 0x95, 0x01, // Report Count (1) 34 + 0x81, 0x02, // Input (Data,Var,Abs) 36 + 0x95, 0x02, // Report Count (2) 38 + 0x81, 0x03, // Input (Cnst,Var,Abs) 40 + 0x75, 0x10, // Report Size (16) 42 + 0x95, 0x01, // Report Count (1) 44 + 0x35, 0x00, // Physical Minimum (0) 46 + 0xa4, // Push 48 + 0x05, 0x01, // Usage Page (Generic Desktop) 49 + 0x09, 0x30, // Usage (X) 51 + 0x65, 0x13, // Unit (EnglishLinear: in) 53 + 0x55, 0x0d, // Unit Exponent (-3) 55 + 0x46, 0xf0, 0x50, // Physical Maximum (20720) 57 + 0x26, 0xff, 0x7f, // Logical Maximum (32767) 60 + 0x81, 0x02, // Input (Data,Var,Abs) 63 + 0x09, 0x31, // Usage (Y) 65 + 0x46, 0x91, 0x2d, // Physical Maximum (11665) 67 + 0x26, 0xff, 0x7f, // Logical Maximum (32767) 70 + 0x81, 0x02, // Input (Data,Var,Abs) 73 + 0xb4, // Pop 75 + 0x09, 0x30, // Usage (Tip Pressure) 76 + 0x45, 0x00, // Physical Maximum (0) 78 + 0x26, 0xff, 0x1f, // Logical Maximum (8191) 80 + 0x81, 0x42, // Input (Data,Var,Abs,Null) 83 + 0x09, 0x3d, // Usage (X Tilt) 85 + 0x15, 0x81, // Logical Minimum (-127) 87 + 0x25, 0x7f, // Logical Maximum (127) 89 + 0x75, 0x08, // Report Size (8) 91 + 0x95, 0x01, // Report Count (1) 93 + 0x81, 0x02, // Input (Data,Var,Abs) 95 + 0x09, 0x3e, // Usage (Y Tilt) 97 + 0x15, 0x81, // Logical Minimum (-127) 99 + 0x25, 0x7f, // Logical Maximum (127) 101 + 0x81, 0x02, // Input (Data,Var,Abs) 103 + 0xc0, // End Collection 105 + 0xc0, // End Collection 106 +}; + +#define BIT(n) (1UL << n) + +#define TIP_SWITCH BIT(0) +#define BARREL_SWITCH BIT(1) +#define ERASER BIT(2) +/* padding BIT(3) */ +/* padding BIT(4) */ +#define IN_RANGE BIT(5) +/* padding BIT(6) */ +/* padding BIT(7) */ + +#define U16(index) (data[index] | (data[index + 1] << 8)) + +SEC("fmod_ret/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 */); + + if (!data) + return 0; /* EPERM check */ + + __builtin_memcpy(data, fixed_rdesc, sizeof(fixed_rdesc)); + + return sizeof(fixed_rdesc); +} + +static __u8 prev_state = 0; + +/* + * There are a few cases where the device is sending wrong event + * sequences, all related to the second button (the pen doesn't + * have an eraser switch on the tail end): + * + * whenever the second button gets pressed or released, an + * out-of-proximity event is generated and then the firmware + * compensate for the missing state (and the firmware uses + * eraser for that button): + * + * - if the pen is in range, an extra out-of-range is sent + * when the second button is pressed/released: + * // Pen is in range + * E: InRange + * + * // Second button is pressed + * E: + * E: Eraser InRange + * + * // Second button is released + * E: + * E: InRange + * + * This case is ignored by this filter, it's "valid" + * and userspace knows how to deal with it, there are just + * a few out-of-prox events generated, but the user doesn´t + * see them. + * + * - if the pen is in contact, 2 extra events are added when + * the second button is pressed/released: an out of range + * and an in range: + * + * // Pen is in contact + * E: TipSwitch InRange + * + * // Second button is pressed + * E: <- false release, needs to be filtered out + * E: Eraser InRange <- false release, needs to be filtered out + * E: TipSwitch Eraser InRange + * + * // Second button is released + * E: <- false release, needs to be filtered out + * E: InRange <- false release, needs to be filtered out + * E: TipSwitch InRange + * + */ +SEC("fmod_ret/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 */); + __u8 current_state, changed_state; + bool prev_tip; + __u16 tilt; + + if (!data) + return 0; /* EPERM check */ + + current_state = data[1]; + + /* if the state is identical to previously, early return */ + if (current_state == prev_state) + return 0; + + prev_tip = !!(prev_state & TIP_SWITCH); + + /* + * Illegal transition: pen is in range with the tip pressed, and + * it goes into out of proximity. + * + * Ideally we should hold the event, start a timer and deliver it + * only if the timer ends, but we are not capable of that now. + * + * And it doesn't matter because when we are in such cases, this + * means we are detecting a false release. + */ + if ((current_state & IN_RANGE) == 0) { + if (prev_tip) + return HID_IGNORE_EVENT; + return 0; + } + + /* + * XOR to only set the bits that have changed between + * previous and current state + */ + changed_state = prev_state ^ current_state; + + /* Store the new state for future processing */ + prev_state = current_state; + + /* + * We get both a tipswitch and eraser change in the same HID report: + * this is not an authorized transition and is unlikely to happen + * in real life. + * This is likely to be added by the firmware to emulate the + * eraser mode so we can skip the event. + */ + 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"; diff --git a/drivers/hid/bpf/progs/hid_bpf.h b/drivers/hid/bpf/progs/hid_bpf.h new file mode 100644 index 000000000000..7ee371cac2e1 --- /dev/null +++ b/drivers/hid/bpf/progs/hid_bpf.h @@ -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 */ diff --git a/drivers/hid/bpf/progs/hid_bpf_helpers.h b/drivers/hid/bpf/progs/hid_bpf_helpers.h new file mode 100644 index 000000000000..1d53b10aaa2e --- /dev/null +++ b/drivers/hid/bpf/progs/hid_bpf_helpers.h @@ -0,0 +1,170 @@ +/* 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 + +/* duplicated from incluse/linux/array_size.h + */ +#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 */ -- 2.44.0
