/* 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 #include 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 */ #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 */ #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 */