1  /* x86 cache info.
       2     Copyright (C) 2003-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #if IS_IN (libc)
      20  
      21  #include <unistd.h>
      22  #include <ldsodefs.h>
      23  
      24  /* Get the value of the system variable NAME.  */
      25  long int
      26  attribute_hidden
      27  __cache_sysconf (int name)
      28  {
      29    const struct cpu_features *cpu_features = __get_cpu_features ();
      30    switch (name)
      31      {
      32      case _SC_LEVEL1_ICACHE_SIZE:
      33        return cpu_features->level1_icache_size;
      34  
      35      case _SC_LEVEL1_ICACHE_LINESIZE:
      36        return cpu_features->level1_icache_linesize;
      37  
      38      case _SC_LEVEL1_DCACHE_SIZE:
      39        return cpu_features->level1_dcache_size;
      40  
      41      case _SC_LEVEL1_DCACHE_ASSOC:
      42        return cpu_features->level1_dcache_assoc;
      43  
      44      case _SC_LEVEL1_DCACHE_LINESIZE:
      45        return cpu_features->level1_dcache_linesize;
      46  
      47      case _SC_LEVEL2_CACHE_SIZE:
      48        return cpu_features->level2_cache_size;
      49  
      50      case _SC_LEVEL2_CACHE_ASSOC:
      51        return cpu_features->level2_cache_assoc;
      52  
      53      case _SC_LEVEL2_CACHE_LINESIZE:
      54        return cpu_features->level2_cache_linesize;
      55  
      56      case _SC_LEVEL3_CACHE_SIZE:
      57        return cpu_features->level3_cache_size;
      58  
      59      case _SC_LEVEL3_CACHE_ASSOC:
      60        return cpu_features->level3_cache_assoc;
      61  
      62      case _SC_LEVEL3_CACHE_LINESIZE:
      63        return cpu_features->level3_cache_linesize;
      64  
      65      case _SC_LEVEL4_CACHE_SIZE:
      66        return cpu_features->level4_cache_size;
      67  
      68      default:
      69        break;
      70      }
      71    return -1;
      72  }
      73  
      74  # ifdef SHARED
      75  /* NB: In libc.a, cacheinfo.h is included in libc-start.c.  In libc.so,
      76     cacheinfo.h is included here and call init_cacheinfo by initializing
      77     a dummy function pointer via IFUNC relocation after CPU features in
      78     ld.so have been initialized by DL_PLATFORM_INIT or IFUNC relocation.  */
      79  # include <cacheinfo.h>
      80  # include <ifunc-init.h>
      81  
      82  extern void __x86_cacheinfo (void) attribute_hidden;
      83  void (*const __x86_cacheinfo_p) (void) attribute_hidden
      84    = __x86_cacheinfo;
      85  
      86  __ifunc (__x86_cacheinfo, __x86_cacheinfo, NULL, void, init_cacheinfo);
      87  # endif
      88  #endif