1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* Copyright (c) 2022 Benjamin Tissoires
5 #ifndef __HID_BPF_HELPERS_H
6 #define __HID_BPF_HELPERS_H
9 #include <bpf/bpf_helpers.h>
10 #include <linux/errno.h>
12 extern __u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx,
14 const size_t __sz) __ksym;
15 extern struct hid_bpf_ctx *hid_bpf_allocate_context(unsigned int hid_id) __ksym;
16 extern void hid_bpf_release_context(struct hid_bpf_ctx *ctx) __ksym;
17 extern int hid_bpf_hw_request(struct hid_bpf_ctx *ctx,
20 enum hid_report_type type,
21 enum hid_class_request reqtype) __ksym;
23 #define HID_MAX_DESCRIPTOR_SIZE 4096
24 #define HID_IGNORE_EVENT -1
26 /* extracted from <linux/input.h> */
29 #define BUS_ISAPNP 0x02
32 #define BUS_BLUETOOTH 0x05
33 #define BUS_VIRTUAL 0x06
35 #define BUS_I8042 0x11
36 #define BUS_XTKBD 0x12
37 #define BUS_RS232 0x13
38 #define BUS_GAMEPORT 0x14
39 #define BUS_PARPORT 0x15
40 #define BUS_AMIGA 0x16
45 #define BUS_ATARI 0x1B
49 #define BUS_INTEL_ISHTP 0x1F
50 #define BUS_AMD_SFH 0x20
52 /* extracted from <linux/hid.h> */
53 #define HID_GROUP_ANY 0x0000
54 #define HID_GROUP_GENERIC 0x0001
55 #define HID_GROUP_MULTITOUCH 0x0002
56 #define HID_GROUP_SENSOR_HUB 0x0003
57 #define HID_GROUP_MULTITOUCH_WIN_8 0x0004
58 #define HID_GROUP_RMI 0x0100
59 #define HID_GROUP_WACOM 0x0101
60 #define HID_GROUP_LOGITECH_DJ_DEVICE 0x0102
61 #define HID_GROUP_STEAM 0x0103
62 #define HID_GROUP_LOGITECH_27MHZ_DEVICE 0x0104
63 #define HID_GROUP_VIVALDI 0x0105
65 /* include/linux/mod_devicetable.h defines as (~0), but that gives us negative size arrays */
66 #define HID_VID_ANY 0x0000
67 #define HID_PID_ANY 0x0000
69 #define BIT(n) (1UL << (n))
70 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
72 /* Helper macro to convert (foo, __LINE__) into foo134 so we can use __LINE__ for
73 * field/variable names
75 #define COMBINE1(X, Y) X ## Y
76 #define COMBINE(X, Y) COMBINE1(X, Y)
79 * __uint(foo, 123) creates a int (*foo)[1234]
81 * We use that macro to declare an anonymous struct with several
82 * fields, each is the declaration of an pointer to an array of size
83 * bus/group/vid/pid. (Because it's a pointer to such an array, actual storage
84 * would be sizeof(pointer) rather than sizeof(array). Not that we ever
85 * instantiate it anyway).
87 * This is only used for BTF introspection, we can later check "what size
88 * is the bus array" in the introspection data and thus extract the bus ID
91 * And we use the __LINE__ to give each of our structs a unique name so the
92 * BPF program writer doesn't have to.
94 * $ bpftool btf dump file target/bpf/HP_Elite_Presenter.bpf.o
95 * shows the inspection data, start by searching for .hid_bpf_config
96 * and working backwards from that (each entry references the type_id of the
100 #define HID_DEVICE(b, g, ven, prod) \
104 __uint(group, (g)); \
105 __uint(vid, (ven)); \
106 __uint(pid, (prod)); \
107 } COMBINE(_entry, __LINE__)
109 /* Macro magic below is to make HID_BPF_CONFIG() look like a function call that
110 * we can pass multiple HID_DEVICE() invocations in.
112 * For up to 16 arguments, HID_BPF_CONFIG(one, two) resolves to
117 * } _device_ids SEC(".hid_bpf_config")
121 /* Returns the number of macro arguments, this expands
122 * NARGS(a, b, c) to NTH_ARG(a, b, c, 15, 14, 13, .... 4, 3, 2, 1).
123 * NTH_ARG always returns the 16th argument which in our case is 3.
125 * If we want more than 16 values _COUNTDOWN and _NTH_ARG both need to be
128 #define _NARGS(...) _NARGS1(__VA_ARGS__, _COUNTDOWN)
129 #define _NARGS1(...) _NTH_ARG(__VA_ARGS__)
131 /* Add to this if we need more than 16 args */
133 15, 14, 13, 12, 11, 10, 9, 8, \
134 7, 6, 5, 4, 3, 2, 1, 0
136 /* Return the 16 argument passed in. See _NARGS above for usage. Note this is
140 _1, _2, _3, _4, _5, _6, _7, _8, \
141 _9, _10, _11, _12, _13, _14, _15,\
144 /* Turns EXPAND(_ARG, a, b, c) into _ARG3(a, b, c) */
145 #define _EXPAND(func, ...) COMBINE(func, _NARGS(__VA_ARGS__)) (__VA_ARGS__)
147 /* And now define all the ARG macros for each number of args we want to accept */
148 #define _ARG1(_1) _1;
149 #define _ARG2(_1, _2) _1; _2;
150 #define _ARG3(_1, _2, _3) _1; _2; _3;
151 #define _ARG4(_1, _2, _3, _4) _1; _2; _3; _4;
152 #define _ARG5(_1, _2, _3, _4, _5) _1; _2; _3; _4; _5;
153 #define _ARG6(_1, _2, _3, _4, _5, _6) _1; _2; _3; _4; _5; _6;
154 #define _ARG7(_1, _2, _3, _4, _5, _6, _7) _1; _2; _3; _4; _5; _6; _7;
155 #define _ARG8(_1, _2, _3, _4, _5, _6, _7, _8) _1; _2; _3; _4; _5; _6; _7; _8;
156 #define _ARG9(_1, _2, _3, _4, _5, _6, _7, _8, _9) _1; _2; _3; _4; _5; _6; _7; _8; _9;
157 #define _ARG10(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a;
158 #define _ARG11(_1, _2, _3, _4, _5, _6, _7, _8, _9, _a, _b) _1; _2; _3; _4; _5; _6; _7; _8; _9; _a; _b;
159 #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;
160 #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;
161 #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;
162 #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;
165 #define HID_BPF_CONFIG(...) union { \
166 _EXPAND(_ARG, __VA_ARGS__) \
167 } _device_ids SEC(".hid_bpf_config")
169 #endif /* __HID_BPF_HELPERS_H */