| /* Initialize CPU feature data. |
| This file is part of the GNU C Library. |
| Copyright (C) 2008-2014 Free Software Foundation, Inc. |
| Contributed by Ulrich Drepper <drepper@redhat.com>. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #include <atomic.h> |
| #include <cpuid.h> |
| #include "init-arch.h" |
| |
| |
| struct cpu_features __cpu_features attribute_hidden; |
| |
| |
| static void |
| get_common_indeces (unsigned int *family, unsigned int *model) |
| { |
| __cpuid (1, __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ebx, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_1].edx); |
| |
| unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax; |
| *family = (eax >> 8) & 0x0f; |
| *model = (eax >> 4) & 0x0f; |
| } |
| |
| |
| void |
| __init_cpu_features (void) |
| { |
| unsigned int ebx; |
| unsigned int ecx; |
| unsigned int edx; |
| unsigned int family = 0; |
| unsigned int model = 0; |
| enum cpu_features_kind kind; |
| |
| __cpuid (0, __cpu_features.max_cpuid, ebx, ecx, edx); |
| |
| /* This spells out "GenuineIntel". */ |
| if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69) |
| { |
| kind = arch_kind_intel; |
| |
| get_common_indeces (&family, &model); |
| |
| unsigned int eax = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].eax; |
| unsigned int extended_family = (eax >> 20) & 0xff; |
| unsigned int extended_model = (eax >> 12) & 0xf0; |
| if (family == 0x0f) |
| { |
| family += extended_family; |
| model += extended_model; |
| } |
| else if (family == 0x06) |
| { |
| ecx = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx; |
| model += extended_model; |
| switch (model) |
| { |
| case 0x1c: |
| case 0x26: |
| /* BSF is slow on Atom. */ |
| __cpu_features.feature[index_Slow_BSF] |= bit_Slow_BSF; |
| break; |
| |
| case 0x37: |
| /* Unaligned load versions are faster than SSSE3 |
| on Silvermont. */ |
| #if index_Fast_Unaligned_Load != index_Prefer_PMINUB_for_stringop |
| # error index_Fast_Unaligned_Load != index_Prefer_PMINUB_for_stringop |
| #endif |
| #if index_Fast_Unaligned_Load != index_Slow_SSE4_2 |
| # error index_Fast_Unaligned_Load != index_Slow_SSE4_2 |
| #endif |
| __cpu_features.feature[index_Fast_Unaligned_Load] |
| |= (bit_Fast_Unaligned_Load |
| | bit_Prefer_PMINUB_for_stringop |
| | bit_Slow_SSE4_2); |
| break; |
| |
| default: |
| /* Unknown family 0x06 processors. Assuming this is one |
| of Core i3/i5/i7 processors if AVX is available. */ |
| if ((ecx & bit_AVX) == 0) |
| break; |
| |
| case 0x1a: |
| case 0x1e: |
| case 0x1f: |
| case 0x25: |
| case 0x2c: |
| case 0x2e: |
| case 0x2f: |
| /* Rep string instructions, copy backward, unaligned loads |
| and pminub are fast on Intel Core i3, i5 and i7. */ |
| #if index_Fast_Rep_String != index_Fast_Copy_Backward |
| # error index_Fast_Rep_String != index_Fast_Copy_Backward |
| #endif |
| #if index_Fast_Rep_String != index_Fast_Unaligned_Load |
| # error index_Fast_Rep_String != index_Fast_Unaligned_Load |
| #endif |
| #if index_Fast_Rep_String != index_Prefer_PMINUB_for_stringop |
| # error index_Fast_Rep_String != index_Prefer_PMINUB_for_stringop |
| #endif |
| __cpu_features.feature[index_Fast_Rep_String] |
| |= (bit_Fast_Rep_String |
| | bit_Fast_Copy_Backward |
| | bit_Fast_Unaligned_Load |
| | bit_Prefer_PMINUB_for_stringop); |
| break; |
| } |
| } |
| } |
| /* This spells out "AuthenticAMD". */ |
| else if (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65) |
| { |
| kind = arch_kind_amd; |
| |
| get_common_indeces (&family, &model); |
| |
| ecx = __cpu_features.cpuid[COMMON_CPUID_INDEX_1].ecx; |
| |
| unsigned int eax; |
| __cpuid (0x80000000, eax, ebx, ecx, edx); |
| if (eax >= 0x80000001) |
| __cpuid (0x80000001, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_80000001].eax, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_80000001].ebx, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_80000001].ecx, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_80000001].edx); |
| } |
| else |
| kind = arch_kind_other; |
| |
| if (__cpu_features.max_cpuid >= 7) |
| __cpuid_count (7, 0, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_7].eax, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_7].ebx, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_7].ecx, |
| __cpu_features.cpuid[COMMON_CPUID_INDEX_7].edx); |
| |
| /* Can we call xgetbv? */ |
| if (CPUID_OSXSAVE) |
| { |
| unsigned int xcrlow; |
| unsigned int xcrhigh; |
| asm ("xgetbv" : "=a" (xcrlow), "=d" (xcrhigh) : "c" (0)); |
| /* Is YMM and XMM state usable? */ |
| if ((xcrlow & (bit_YMM_state | bit_XMM_state)) == |
| (bit_YMM_state | bit_XMM_state)) |
| { |
| /* Determine if AVX is usable. */ |
| if (CPUID_AVX) |
| __cpu_features.feature[index_AVX_Usable] |= bit_AVX_Usable; |
| /* Determine if FMA is usable. */ |
| if (CPUID_FMA) |
| __cpu_features.feature[index_FMA_Usable] |= bit_FMA_Usable; |
| /* Determine if FMA4 is usable. */ |
| if (CPUID_FMA4) |
| __cpu_features.feature[index_FMA4_Usable] |= bit_FMA4_Usable; |
| } |
| } |
| |
| __cpu_features.family = family; |
| __cpu_features.model = model; |
| atomic_write_barrier (); |
| __cpu_features.kind = kind; |
| } |
| |
| #undef __get_cpu_features |
| |
| const struct cpu_features * |
| __get_cpu_features (void) |
| { |
| if (__cpu_features.kind == arch_kind_unknown) |
| __init_cpu_features (); |
| |
| return &__cpu_features; |
| } |