1 /* Copyright (c) 2016 Facebook 2 * 3 * This program is free software; you can redistribute it and/or 4 * modify it under the terms of version 2 of the GNU General Public 5 * License as published by the Free Software Foundation. 6 */ 7 #include <linux/ptrace.h> 8 #include <linux/version.h> 9 #include <uapi/linux/bpf.h> 10 #include <uapi/linux/bpf_perf_event.h> 11 #include <uapi/linux/perf_event.h> 12 #include "bpf_helpers.h" 13 14 struct key_t { 15 char comm[TASK_COMM_LEN]; 16 u32 kernstack; 17 u32 userstack; 18 }; 19 20 struct bpf_map_def SEC("maps") counts = { 21 .type = BPF_MAP_TYPE_HASH, 22 .key_size = sizeof(struct key_t), 23 .value_size = sizeof(u64), 24 .max_entries = 10000, 25 }; 26 27 struct bpf_map_def SEC("maps") stackmap = { 28 .type = BPF_MAP_TYPE_STACK_TRACE, 29 .key_size = sizeof(u32), 30 .value_size = PERF_MAX_STACK_DEPTH * sizeof(u64), 31 .max_entries = 10000, 32 }; 33 34 #define KERN_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP) 35 #define USER_STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP | BPF_F_USER_STACK) 36 37 SEC("perf_event") 38 int bpf_prog1(struct bpf_perf_event_data *ctx) 39 { 40 char fmt[] = "CPU-%d period %lld ip %llx"; 41 u32 cpu = bpf_get_smp_processor_id(); 42 struct key_t key; 43 u64 *val, one = 1; 44 45 if (ctx->sample_period < 10000) 46 /* ignore warmup */ 47 return 0; 48 bpf_get_current_comm(&key.comm, sizeof(key.comm)); 49 key.kernstack = bpf_get_stackid(ctx, &stackmap, KERN_STACKID_FLAGS); 50 key.userstack = bpf_get_stackid(ctx, &stackmap, USER_STACKID_FLAGS); 51 if ((int)key.kernstack < 0 && (int)key.userstack < 0) { 52 bpf_trace_printk(fmt, sizeof(fmt), cpu, ctx->sample_period, 53 PT_REGS_IP(&ctx->regs)); 54 return 0; 55 } 56 57 val = bpf_map_lookup_elem(&counts, &key); 58 if (val) 59 (*val)++; 60 else 61 bpf_map_update_elem(&counts, &key, &one, BPF_NOEXIST); 62 return 0; 63 } 64 65 char _license[] SEC("license") = "GPL"; 66