1 // SPDX-License-Identifier: GPL-2.0
2 #ifndef _PERF_BPF_H
3 #define _PERF_BPF_H
4 
5 #include <uapi/linux/bpf.h>
6 
7 /*
8  * A helper structure used by eBPF C program to describe map attributes to
9  * elf_bpf loader, taken from tools/testing/selftests/bpf/bpf_helpers.h:
10  */
11 struct bpf_map {
12         unsigned int type;
13         unsigned int key_size;
14         unsigned int value_size;
15         unsigned int max_entries;
16         unsigned int map_flags;
17         unsigned int inner_map_idx;
18         unsigned int numa_node;
19 };
20 
21 #define bpf_map(name, _type, type_key, type_val, _max_entries)	\
22 struct bpf_map SEC("maps") name = {				\
23 	.type	     = BPF_MAP_TYPE_##_type,			\
24 	.key_size    = sizeof(type_key),			\
25 	.value_size  = sizeof(type_val),			\
26 	.max_entries = _max_entries,				\
27 };								\
28 struct ____btf_map_##name {					\
29 	type_key key;						\
30 	type_val value;                                 	\
31 };								\
32 struct ____btf_map_##name __attribute__((section(".maps." #name), used)) \
33 	____btf_map_##name = { }
34 
35 /*
36  * FIXME: this should receive .max_entries as a parameter, as careful
37  *	  tuning of these limits is needed to avoid hitting limits that
38  *	  prevents other BPF constructs, such as tracepoint handlers,
39  *	  to get installed, with cryptic messages from libbpf, etc.
40  *	  For the current need, 'perf trace --filter-pids', 64 should
41  *	  be good enough, but this surely needs to be revisited.
42  */
43 #define pid_map(name, value_type) bpf_map(name, HASH, pid_t, value_type, 64)
44 
45 static int (*bpf_map_update_elem)(struct bpf_map *map, void *key, void *value, u64 flags) = (void *)BPF_FUNC_map_update_elem;
46 static void *(*bpf_map_lookup_elem)(struct bpf_map *map, void *key) = (void *)BPF_FUNC_map_lookup_elem;
47 
48 static void (*bpf_tail_call)(void *ctx, void *map, int index) = (void *)BPF_FUNC_tail_call;
49 
50 #define SEC(NAME) __attribute__((section(NAME),  used))
51 
52 #define probe(function, vars) \
53 	SEC(#function "=" #function " " #vars) function
54 
55 #define syscall_enter(name) \
56 	SEC("syscalls:sys_enter_" #name) syscall_enter_ ## name
57 
58 #define syscall_exit(name) \
59 	SEC("syscalls:sys_exit_" #name) syscall_exit_ ## name
60 
61 #define license(name) \
62 char _license[] SEC("license") = #name; \
63 int _version SEC("version") = LINUX_VERSION_CODE;
64 
65 static int (*probe_read)(void *dst, int size, const void *unsafe_addr) = (void *)BPF_FUNC_probe_read;
66 static int (*probe_read_str)(void *dst, int size, const void *unsafe_addr) = (void *)BPF_FUNC_probe_read_str;
67 
68 static int (*perf_event_output)(void *, struct bpf_map *, int, void *, unsigned long) = (void *)BPF_FUNC_perf_event_output;
69 
70 #endif /* _PERF_BPF_H */
71