LXR linux/tools/testing/selftests/bpf/progs/test

   1#include "vmlinux.h"
   2#include <bpf/bpf_helpers.h>
   3#include <bpf/bpf_core_read.h>
   4
   5const char LICENSE[] SEC("license") = "GPL";
   6
   7__noinline int sub1(int x)
   8{
   9        return x + 1;
  10}
  11
  12static __noinline int sub5(int v);
  13
  14__noinline int sub2(int y)
  15{
  16        return sub5(y + 2);
  17}
  18
  19static __noinline int sub3(int z)
  20{
  21        return z + 3 + sub1(4);
  22}
  23
  24static __noinline int sub4(int w)
  25{
  26        return w + sub3(5) + sub1(6);
  27}
  28
  29/* sub5() is an identitify function, just to test weirder functions layout and
  30 * call patterns
  31 */
  32static __noinline int sub5(int v)
  33{
  34        return sub1(v) - 1; /* compensates sub1()'s + 1 */
  35}
  36
  37/* unfortunately verifier rejects `struct task_struct *t` as an unkown pointer
  38 * type, so we need to accept pointer as integer and then cast it inside the
  39 * function
  40 */
  41__noinline int get_task_tgid(uintptr_t t)
  42{
  43        /* this ensures that CO-RE relocs work in multi-subprogs .text */
  44        return BPF_CORE_READ((struct task_struct *)(void *)t, tgid);
  45}
  46
  47int res1 = 0;
  48int res2 = 0;
  49int res3 = 0;
  50int res4 = 0;
  51
  52SEC("raw_tp/sys_enter")
  53int prog1(void *ctx)
  54{
  55        /* perform some CO-RE relocations to ensure they work with multi-prog
  56         * sections correctly
  57         */
  58        struct task_struct *t = (void *)bpf_get_current_task();
  59
  60        if (!BPF_CORE_READ(t, pid) || !get_task_tgid((uintptr_t)t))
  61                return 1;
  62
  63        res1 = sub1(1) + sub3(2); /* (1 + 1) + (2 + 3 + (4 + 1)) = 12 */
  64        return 0;
  65}
  66
  67SEC("raw_tp/sys_exit")
  68int prog2(void *ctx)
  69{
  70        struct task_struct *t = (void *)bpf_get_current_task();
  71
  72        if (!BPF_CORE_READ(t, pid) || !get_task_tgid((uintptr_t)t))
  73                return 1;
  74
  75        res2 = sub2(3) + sub3(4); /* (3 + 2) + (4 + 3 + (4 + 1)) = 17 */
  76        return 0;
  77}
  78
  79/* prog3 has the same section name as prog1 */
  80SEC("raw_tp/sys_enter")
  81int prog3(void *ctx)
  82{
  83        struct task_struct *t = (void *)bpf_get_current_task();
  84
  85        if (!BPF_CORE_READ(t, pid) || !get_task_tgid((uintptr_t)t))
  86                return 1;
  87
  88        res3 = sub3(5) + 6; /* (5 + 3 + (4 + 1)) + 6 = 19 */
  89        return 0;
  90}
  91
  92/* prog4 has the same section name as prog2 */
  93SEC("raw_tp/sys_exit")
  94int prog4(void *ctx)
  95{
  96        struct task_struct *t = (void *)bpf_get_current_task();
  97
  98        if (!BPF_CORE_READ(t, pid) || !get_task_tgid((uintptr_t)t))
  99                return 1;
 100
 101        res4 = sub4(7) + sub1(8); /* (7 + (5 + 3 + (4 + 1)) + (6 + 1)) + (8 + 1) = 36 */
 102        return 0;
 103}
 104