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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
   3 #include <vmlinux.h>
   4 #include <bpf/bpf_tracing.h>
   5 #include <bpf/bpf_helpers.h>
   6 #include "../bpf_testmod/bpf_testmod_kfunc.h"
   7
   8 static struct prog_test_ref_kfunc __kptr *v;
   9 long total_sum = -1;
  10
  11 SEC("tc")
  12 int test_jit_probe_mem(struct __sk_buff *ctx)
  13 {
  14         struct prog_test_ref_kfunc *p;
  15         unsigned long zero = 0, sum;
  16
  17         p = bpf_kfunc_call_test_acquire(&zero);
  18         if (!p)
  19                 return 1;
  20
  21         p = bpf_kptr_xchg(&v, p);
  22         if (p)
  23                 goto release_out;
  24
  25         /* Direct map value access of kptr, should be PTR_UNTRUSTED */
  26         p = v;
  27         if (!p)
  28                 return 1;
  29
  30         asm volatile (
  31                 "r9 = %[p];"
  32                 "%[sum] = 0;"
  33
  34                 /* r8 = p->a */
  35                 "r8 = *(u32 *)(r9 + 0);"
  36                 "%[sum] += r8;"
  37
  38                 /* r8 = p->b */
  39                 "r8 = *(u32 *)(r9 + 4);"
  40                 "%[sum] += r8;"
  41
  42                 "r9 += 8;"
  43                 /* r9 = p->a */
  44                 "r9 = *(u32 *)(r9 - 8);"
  45                 "%[sum] += r9;"
  46
  47                 : [sum] "=r"(sum)
  48                 : [p] "r"(p)
  49                 : "r8", "r9"
  50         );
  51
  52         total_sum = sum;
  53         return 0;
  54 release_out:
  55         bpf_kfunc_call_test_release(p);
  56         return 1;
  57 }
  58
  59 char _license[] SEC("license") = "GPL";