tools/lib/bpf/libbpf_util.h

   1 /* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
   2 /* Copyright (c) 2019 Facebook */
   3
   4 #ifndef __LIBBPF_LIBBPF_UTIL_H
   5 #define __LIBBPF_LIBBPF_UTIL_H
   6
   7 #include <stdbool.h>
   8 #include <linux/compiler.h>
   9
  10 #ifdef __cplusplus
  11 extern "C" {
  12 #endif
  13
  14 /* Use these barrier functions instead of smp_[rw]mb() when they are
  15  * used in a libbpf header file. That way they can be built into the
  16  * application that uses libbpf.
  17  */
  18 #if defined(__i386__) || defined(__x86_64__)
  19 # define libbpf_smp_store_release(p, v)                                 \
  20         do {                                                            \
  21                 asm volatile("" : : : "memory");                        \
  22                 WRITE_ONCE(*p, v);                                      \
  23         } while (0)
  24 # define libbpf_smp_load_acquire(p)                                     \
  25         ({                                                              \
  26                 typeof(*p) ___p1 = READ_ONCE(*p);                       \
  27                 asm volatile("" : : : "memory");                        \
  28                 ___p1;                                                  \
  29         })
  30 #elif defined(__aarch64__)
  31 # define libbpf_smp_store_release(p, v)                                 \
  32                 asm volatile ("stlr %w1, %0" : "=Q" (*p) : "r" (v) : "memory")
  33 # define libbpf_smp_load_acquire(p)                                     \
  34         ({                                                              \
  35                 typeof(*p) ___p1;                                       \
  36                 asm volatile ("ldar %w0, %1"                            \
  37                               : "=r" (___p1) : "Q" (*p) : "memory");    \
  38                 __p1;                                                   \
  39         })
  40 #elif defined(__riscv)
  41 # define libbpf_smp_store_release(p, v)                                 \
  42         do {                                                            \
  43                 asm volatile ("fence rw,w" : : : "memory");             \
  44                 WRITE_ONCE(*p, v);                                      \
  45         } while (0)
  46 # define libbpf_smp_load_acquire(p)                                     \
  47         ({                                                              \
  48                 typeof(*p) ___p1 = READ_ONCE(*p);                       \
  49                 asm volatile ("fence r,rw" : : : "memory");             \
  50                 ___p1;                                                  \
  51         })
  52 #endif
  53
  54 #ifndef libbpf_smp_store_release
  55 #define libbpf_smp_store_release(p, v)                                  \
  56         do {                                                            \
  57                 __sync_synchronize();                                   \
  58                 WRITE_ONCE(*p, v);                                      \
  59         } while (0)
  60 #endif
  61
  62 #ifndef libbpf_smp_load_acquire
  63 #define libbpf_smp_load_acquire(p)                                      \
  64         ({                                                              \
  65                 typeof(*p) ___p1 = READ_ONCE(*p);                       \
  66                 __sync_synchronize();                                   \
  67                 ___p1;                                                  \
  68         })
  69 #endif
  70
  71 #ifdef __cplusplus
  72 } /* extern "C" */
  73 #endif
  74
  75 #endif