src/ceph/src/arch/arm.c

   1 #include "acconfig.h"
   2 #include "arch/probe.h"
   3
   4 /* flags we export */
   5 int ceph_arch_neon = 0;
   6 int ceph_arch_aarch64_crc32 = 0;
   7
   8 #include <stdio.h>
   9
  10 #if __linux__
  11
  12 #include <elf.h>
  13 #include <link.h> // ElfW macro
  14
  15 #if __arm__ || __aarch64__
  16 #include <asm/hwcap.h>
  17 #endif // __arm__
  18
  19 static unsigned long get_auxval(unsigned long type)
  20 {
  21         unsigned long result = 0;
  22         FILE *f = fopen("/proc/self/auxv", "r");
  23         if (f) {
  24                 ElfW(auxv_t) entry;
  25                 while (fread(&entry, sizeof(entry), 1, f) == 1) {
  26                         if (entry.a_type == type) {
  27                                 result = entry.a_un.a_val;
  28                                 break;
  29                         }
  30                 }
  31                 fclose(f);
  32         }
  33         return result;
  34 }
  35
  36 static unsigned long get_hwcap(void)
  37 {
  38         return get_auxval(AT_HWCAP);
  39 }
  40
  41 #endif // __linux__
  42
  43 int ceph_arch_arm_probe(void)
  44 {
  45 #if __arm__ && __linux__
  46         ceph_arch_neon = (get_hwcap() & HWCAP_NEON) == HWCAP_NEON;
  47 #elif __aarch64__ && __linux__
  48         ceph_arch_neon = (get_hwcap() & HWCAP_ASIMD) == HWCAP_ASIMD;
  49 # if defined(HAVE_ARMV8_CRC) && defined(HWCAP_CRC32)
  50         ceph_arch_aarch64_crc32 = (get_hwcap() & HWCAP_CRC32) == HWCAP_CRC32;
  51 # endif
  52 #else
  53         if (0)
  54                 get_hwcap();  // make compiler shut up
  55 #endif
  56         return 0;
  57 }
  58