tools/perf/include/bpf/bpf.h

   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 */