root/samples/bpf/spintest_kern.c

   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/skbuff.h>
   8 #include <linux/netdevice.h>
   9 #include <linux/version.h>
  10 #include <uapi/linux/bpf.h>
  11 #include <uapi/linux/perf_event.h>
  12 #include "bpf_helpers.h"
  13 
  14 struct bpf_map_def SEC("maps") my_map = {
  15         .type = BPF_MAP_TYPE_HASH,
  16         .key_size = sizeof(long),
  17         .value_size = sizeof(long),
  18         .max_entries = 1024,
  19 };
  20 struct bpf_map_def SEC("maps") my_map2 = {
  21         .type = BPF_MAP_TYPE_PERCPU_HASH,
  22         .key_size = sizeof(long),
  23         .value_size = sizeof(long),
  24         .max_entries = 1024,
  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 PROG(foo) \
  35 int foo(struct pt_regs *ctx) \
  36 { \
  37         long v = PT_REGS_IP(ctx), *val; \
  38 \
  39         val = bpf_map_lookup_elem(&my_map, &v); \
  40         bpf_map_update_elem(&my_map, &v, &v, BPF_ANY); \
  41         bpf_map_update_elem(&my_map2, &v, &v, BPF_ANY); \
  42         bpf_map_delete_elem(&my_map2, &v); \
  43         bpf_get_stackid(ctx, &stackmap, BPF_F_REUSE_STACKID); \
  44         return 0; \
  45 }
  46 
  47 /* add kprobes to all possible *spin* functions */
  48 SEC("kprobe/spin_unlock")PROG(p1)
  49 SEC("kprobe/spin_lock")PROG(p2)
  50 SEC("kprobe/mutex_spin_on_owner")PROG(p3)
  51 SEC("kprobe/rwsem_spin_on_owner")PROG(p4)
  52 SEC("kprobe/spin_unlock_irqrestore")PROG(p5)
  53 SEC("kprobe/_raw_spin_unlock_irqrestore")PROG(p6)
  54 SEC("kprobe/_raw_spin_unlock_bh")PROG(p7)
  55 SEC("kprobe/_raw_spin_unlock")PROG(p8)
  56 SEC("kprobe/_raw_spin_lock_irqsave")PROG(p9)
  57 SEC("kprobe/_raw_spin_trylock_bh")PROG(p10)
  58 SEC("kprobe/_raw_spin_lock_irq")PROG(p11)
  59 SEC("kprobe/_raw_spin_trylock")PROG(p12)
  60 SEC("kprobe/_raw_spin_lock")PROG(p13)
  61 SEC("kprobe/_raw_spin_lock_bh")PROG(p14)
  62 /* and to inner bpf helpers */
  63 SEC("kprobe/htab_map_update_elem")PROG(p15)
  64 SEC("kprobe/__htab_percpu_map_update_elem")PROG(p16)
  65 SEC("kprobe/htab_map_alloc")PROG(p17)
  66 
  67 char _license[] SEC("license") = "GPL";
  68 u32 _version SEC("version") = LINUX_VERSION_CODE;