diff options
Diffstat (limited to 'drivers/hid/bpf/progs/hid_bpf_helpers.h')
| -rw-r--r-- | drivers/hid/bpf/progs/hid_bpf_helpers.h | 168 |
1 files changed, 168 insertions, 0 deletions
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..8f226f6e886b --- /dev/null +++ b/drivers/hid/bpf/progs/hid_bpf_helpers.h @@ -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 */ |