tools/testing/selftests/bpf/progs/perf_event_stackmap.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2020 Facebook
   3 #include "vmlinux.h"
   4 #include <bpf/bpf_helpers.h>
   5
   6 #ifndef PERF_MAX_STACK_DEPTH
   7 #define PERF_MAX_STACK_DEPTH         127
   8 #endif
   9
  10 typedef __u64 stack_trace_t[PERF_MAX_STACK_DEPTH];
  11 struct {
  12         __uint(type, BPF_MAP_TYPE_STACK_TRACE);
  13         __uint(max_entries, 16384);
  14         __uint(key_size, sizeof(__u32));
  15         __uint(value_size, sizeof(stack_trace_t));
  16 } stackmap SEC(".maps");
  17
  18 struct {
  19         __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
  20         __uint(max_entries, 1);
  21         __type(key, __u32);
  22         __type(value, stack_trace_t);
  23 } stackdata_map SEC(".maps");
  24
  25 long stackid_kernel = 1;
  26 long stackid_user = 1;
  27 long stack_kernel = 1;
  28 long stack_user = 1;
  29
  30 SEC("perf_event")
  31 int oncpu(void *ctx)
  32 {
  33         stack_trace_t *trace;
  34         __u32 key = 0;
  35         long val;
  36
  37         val = bpf_get_stackid(ctx, &stackmap, 0);
  38         if (val > 0)
  39                 stackid_kernel = 2;
  40         val = bpf_get_stackid(ctx, &stackmap, BPF_F_USER_STACK);
  41         if (val > 0)
  42                 stackid_user = 2;
  43
  44         trace = bpf_map_lookup_elem(&stackdata_map, &key);
  45         if (!trace)
  46                 return 0;
  47
  48         val = bpf_get_stack(ctx, trace, sizeof(stack_trace_t), 0);
  49         if (val > 0)
  50                 stack_kernel = 2;
  51
  52         val = bpf_get_stack(ctx, trace, sizeof(stack_trace_t), BPF_F_USER_STACK);
  53         if (val > 0)
  54                 stack_user = 2;
  55
  56         return 0;
  57 }
  58
  59 char LICENSE[] SEC("license") = "GPL";