lib/librte_eal/common/eal_common_cpuflags.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation
   3  */
   4
   5 #include <elf.h>
   6 #include <fcntl.h>
   7 #include <stdio.h>
   8 #include <string.h>
   9 #include <sys/stat.h>
  10 #include <sys/types.h>
  11 #include <unistd.h>
  12
  13 #if defined(__GLIBC__) && defined(__GLIBC_PREREQ)
  14 #if __GLIBC_PREREQ(2, 16)
  15 #include <sys/auxv.h>
  16 #define HAS_AUXV 1
  17 #endif
  18 #endif
  19
  20 #include <rte_common.h>
  21 #include <rte_cpuflags.h>
  22
  23 #ifndef HAS_AUXV
  24 static unsigned long
  25 getauxval(unsigned long type)
  26 {
  27         errno = ENOTSUP;
  28         return 0;
  29 }
  30 #endif
  31
  32 #ifdef RTE_ARCH_64
  33 typedef Elf64_auxv_t Internal_Elfx_auxv_t;
  34 #else
  35 typedef Elf32_auxv_t Internal_Elfx_auxv_t;
  36 #endif
  37
  38
  39 /**
  40  * Provides a method for retrieving values from the auxiliary vector and
  41  * possibly running a string comparison.
  42  *
  43  * @return Always returns a result.  When the result is 0, check errno
  44  * to see if an error occurred during processing.
  45  */
  46 static unsigned long
  47 _rte_cpu_getauxval(unsigned long type, const char *str)
  48 {
  49         unsigned long val;
  50
  51         errno = 0;
  52         val = getauxval(type);
  53
  54         if (!val && (errno == ENOTSUP || errno == ENOENT)) {
  55                 int auxv_fd = open("/proc/self/auxv", O_RDONLY);
  56                 Internal_Elfx_auxv_t auxv;
  57
  58                 if (auxv_fd == -1)
  59                         return 0;
  60
  61                 errno = ENOENT;
  62                 while (read(auxv_fd, &auxv, sizeof(auxv)) == sizeof(auxv)) {
  63                         if (auxv.a_type == type) {
  64                                 errno = 0;
  65                                 val = auxv.a_un.a_val;
  66                                 if (str)
  67                                         val = strcmp((const char *)val, str);
  68                                 break;
  69                         }
  70                 }
  71                 close(auxv_fd);
  72         }
  73
  74         return val;
  75 }
  76
  77 unsigned long
  78 rte_cpu_getauxval(unsigned long type)
  79 {
  80         return _rte_cpu_getauxval(type, NULL);
  81 }
  82
  83 int
  84 rte_cpu_strcmp_auxval(unsigned long type, const char *str)
  85 {
  86         return _rte_cpu_getauxval(type, str);
  87 }
  88
  89 /**
  90  * Checks if the machine is adequate for running the binary. If it is not, the
  91  * program exits with status 1.
  92  */
  93 void
  94 rte_cpu_check_supported(void)
  95 {
  96         if (!rte_cpu_is_supported())
  97                 exit(1);
  98 }
  99
 100 int
 101 rte_cpu_is_supported(void)
 102 {
 103         /* This is generated at compile-time by the build system */
 104         static const enum rte_cpu_flag_t compile_time_flags[] = {
 105                         RTE_COMPILE_TIME_CPUFLAGS
 106         };
 107         unsigned count = RTE_DIM(compile_time_flags), i;
 108         int ret;
 109
 110         for (i = 0; i < count; i++) {
 111                 ret = rte_cpu_get_flag_enabled(compile_time_flags[i]);
 112
 113                 if (ret < 0) {
 114                         fprintf(stderr,
 115                                 "ERROR: CPU feature flag lookup failed with error %d\n",
 116                                 ret);
 117                         return 0;
 118                 }
 119                 if (!ret) {
 120                         fprintf(stderr,
 121                                 "ERROR: This system does not support \"%s\".\n"
 122                                 "Please check that RTE_MACHINE is set correctly.\n",
 123                                 rte_cpu_get_flag_name(compile_time_flags[i]));
 124                         return 0;
 125                 }
 126         }
 127
 128         return 1;
 129 }