1 /* hwf-x86.c - Detect hardware features - x86 part
2 * Copyright (C) 2007, 2011, 2012 Free Software Foundation, Inc.
3 * Copyright (C) 2012 Jussi Kivilinna
5 * This file is part of Libgcrypt.
7 * Libgcrypt is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU Lesser General Public License as
9 * published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
12 * Libgcrypt is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this program; if not, see <http://www.gnu.org/licenses/>.
29 #include "hwf-common.h"
31 #if !defined (__i386__) && !defined (__x86_64__)
32 # error Module build for wrong CPU.
35 /* We use the next macro to decide whether we can test for certain
39 #if defined (__i386__) && SIZEOF_UNSIGNED_LONG == 4 && defined (__GNUC__)
40 # define HAS_X86_CPUID 1
43 is_cpuid_available(void)
47 /* Detect the CPUID feature by testing some undefined behaviour (16
48 vs 32 bit pushf/popf). */
50 ("pushf\n\t" /* Copy flags to EAX. */
52 "movl %%eax, %%ecx\n\t" /* Save flags into ECX. */
53 "xorl $0x200000, %%eax\n\t" /* Toggle ID bit and copy it to the flags. */
56 "pushf\n\t" /* Copy changed flags again to EAX. */
58 "pushl %%ecx\n\t" /* Restore flags from ECX. */
60 "xorl %%eax, %%ecx\n\t" /* Compare flags against saved flags. */
61 "jz .Lno_cpuid%=\n\t" /* Toggling did not work, thus no CPUID. */
62 "movl $1, %0\n" /* Worked. true -> HAS_CPUID. */
66 : "%eax", "%ecx", "cc"
73 get_cpuid(unsigned int in, unsigned int *eax, unsigned int *ebx,
74 unsigned int *ecx, unsigned int *edx)
79 ("pushl %%ebx\n\t" /* Save GOT register. */
83 "popl %%ebx\n\t" /* Restore GOT register. */
84 : "=a" (regs[0]), "=r" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
85 : "0" (in), "1" (0), "2" (0), "3" (0)
113 #endif /* i386 && GNUC */
116 #if defined (__x86_64__) && defined (__GNUC__)
117 # define HAS_X86_CPUID 1
120 is_cpuid_available(void)
126 get_cpuid(unsigned int in, unsigned int *eax, unsigned int *ebx,
127 unsigned int *ecx, unsigned int *edx)
129 unsigned int regs[4];
133 : "=a" (regs[0]), "=b" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
134 : "0" (in), "1" (0), "2" (0), "3" (0)
162 #endif /* x86-64 && GNUC */
167 detect_x86_gnuc (void)
169 char vendor_id[12+1];
170 unsigned int features;
171 unsigned int os_supports_avx_avx2_registers = 0;
172 unsigned int max_cpuid_level;
173 unsigned int result = 0;
175 (void)os_supports_avx_avx2_registers;
177 if (!is_cpuid_available())
180 get_cpuid(0, &max_cpuid_level,
181 (unsigned int *)&vendor_id[0],
182 (unsigned int *)&vendor_id[8],
183 (unsigned int *)&vendor_id[4]);
187 ; /* Just to make "else if" and ifdef macros look pretty. */
188 #ifdef ENABLE_PADLOCK_SUPPORT
189 else if (!strcmp (vendor_id, "CentaurHauls"))
191 /* This is a VIA CPU. Check what PadLock features we have. */
193 /* Check for extended centaur (EAX). */
194 get_cpuid(0xC0000000, &features, NULL, NULL, NULL);
196 /* Has extended centaur features? */
197 if (features > 0xC0000000)
199 /* Ask for the extended feature flags (EDX). */
200 get_cpuid(0xC0000001, NULL, NULL, NULL, &features);
202 /* Test bits 2 and 3 to see whether the RNG exists and is enabled. */
203 if ((features & 0x0C) == 0x0C)
204 result |= HWF_PADLOCK_RNG;
206 /* Test bits 6 and 7 to see whether the ACE exists and is enabled. */
207 if ((features & 0xC0) == 0xC0)
208 result |= HWF_PADLOCK_AES;
210 /* Test bits 10 and 11 to see whether the PHE exists and is
212 if ((features & 0xC00) == 0xC00)
213 result |= HWF_PADLOCK_SHA;
215 /* Test bits 12 and 13 to see whether the MONTMUL exists and is
217 if ((features & 0x3000) == 0x3000)
218 result |= HWF_PADLOCK_MMUL;
221 #endif /*ENABLE_PADLOCK_SUPPORT*/
222 else if (!strcmp (vendor_id, "GenuineIntel"))
224 /* This is an Intel CPU. */
225 result |= HWF_INTEL_CPU;
227 else if (!strcmp (vendor_id, "AuthenticAMD"))
229 /* This is an AMD CPU. */
232 /* Detect Intel features, that might also be supported by other
235 /* Get CPU info and Intel feature flags (ECX). */
236 get_cpuid(1, NULL, NULL, &features, NULL);
238 #ifdef ENABLE_PCLMUL_SUPPORT
239 /* Test bit 1 for PCLMUL. */
240 if (features & 0x00000002)
241 result |= HWF_INTEL_PCLMUL;
243 /* Test bit 9 for SSSE3. */
244 if (features & 0x00000200)
245 result |= HWF_INTEL_SSSE3;
246 #ifdef ENABLE_AESNI_SUPPORT
247 /* Test bit 25 for AES-NI. */
248 if (features & 0x02000000)
249 result |= HWF_INTEL_AESNI;
250 #endif /*ENABLE_AESNI_SUPPORT*/
251 #if defined(ENABLE_AVX_SUPPORT) || defined(ENABLE_AVX2_SUPPORT)
252 /* Test bit 27 for OSXSAVE (required for AVX/AVX2). */
253 if (features & 0x08000000)
255 /* Check that OS has enabled both XMM and YMM state support. */
256 if ((get_xgetbv() & 0x6) == 0x6)
257 os_supports_avx_avx2_registers = 1;
260 #ifdef ENABLE_AVX_SUPPORT
261 /* Test bit 28 for AVX. */
262 if (features & 0x10000000)
263 if (os_supports_avx_avx2_registers)
264 result |= HWF_INTEL_AVX;
265 #endif /*ENABLE_AVX_SUPPORT*/
266 #ifdef ENABLE_DRNG_SUPPORT
267 /* Test bit 30 for RDRAND. */
268 if (features & 0x40000000)
269 result |= HWF_INTEL_RDRAND;
270 #endif /*ENABLE_DRNG_SUPPORT*/
272 /* Check additional Intel feature flags. Early Intel P5 processors report
273 * too high max_cpuid_level, so don't check level 7 if processor does not
274 * support SSE3 (as cpuid:7 contains only features for newer processors).
275 * Source: http://www.sandpile.org/x86/cpuid.htm */
276 if (max_cpuid_level >= 7 && (features & 0x00000001))
278 /* Get CPUID:7 contains further Intel feature flags. */
279 get_cpuid(7, NULL, &features, NULL, NULL);
281 /* Test bit 8 for BMI2. */
282 if (features & 0x00000100)
283 result |= HWF_INTEL_BMI2;
285 #ifdef ENABLE_AVX2_SUPPORT
286 /* Test bit 5 for AVX2. */
287 if (features & 0x00000020)
288 if (os_supports_avx_avx2_registers)
289 result |= HWF_INTEL_AVX2;
290 #endif /*ENABLE_AVX_SUPPORT*/
295 #endif /* HAS_X86_CPUID */
299 _gcry_hwf_detect_x86 (void)
301 #if defined (HAS_X86_CPUID)
302 return detect_x86_gnuc ();