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/* hwf-x86.c - Detect hardware features - x86 part
* Copyright (C) 2007, 2011, 2012 Free Software Foundation, Inc.
* Copyright (C) 2012 Jussi Kivilinna
*
* This file is part of Libgcrypt.
*
* Libgcrypt 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.
*
* Libgcrypt 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 this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <unistd.h>
#include "g10lib.h"
#include "hwf-common.h"
#if !defined (__i386__) && !defined (__x86_64__)
# error Module build for wrong CPU.
#endif
/* We use the next macro to decide whether we can test for certain
features. */
#undef HAS_X86_CPUID
#if defined (__i386__) && SIZEOF_UNSIGNED_LONG == 4 && defined (__GNUC__)
# define HAS_X86_CPUID 1
static int
is_cpuid_available(void)
{
int has_cpuid = 0;
/* Detect the CPUID feature by testing some undefined behaviour (16
vs 32 bit pushf/popf). */
asm volatile
("pushf\n\t" /* Copy flags to EAX. */
"popl %%eax\n\t"
"movl %%eax, %%ecx\n\t" /* Save flags into ECX. */
"xorl $0x200000, %%eax\n\t" /* Toggle ID bit and copy it to the flags. */
"pushl %%eax\n\t"
"popf\n\t"
"pushf\n\t" /* Copy changed flags again to EAX. */
"popl %%eax\n\t"
"pushl %%ecx\n\t" /* Restore flags from ECX. */
"popf\n\t"
"xorl %%eax, %%ecx\n\t" /* Compare flags against saved flags. */
"jz .Lno_cpuid%=\n\t" /* Toggling did not work, thus no CPUID. */
"movl $1, %0\n" /* Worked. true -> HAS_CPUID. */
".Lno_cpuid%=:\n\t"
: "+r" (has_cpuid)
:
: "%eax", "%ecx", "cc"
);
return has_cpuid;
}
static void
get_cpuid(unsigned int in, unsigned int *eax, unsigned int *ebx,
unsigned int *ecx, unsigned int *edx)
{
unsigned int regs[4];
asm volatile
("pushl %%ebx\n\t" /* Save GOT register. */
"cpuid\n\t"
"movl %%ebx, %1\n\t"
"popl %%ebx\n\t" /* Restore GOT register. */
: "=a" (regs[0]), "=r" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
: "0" (in)
: "cc"
);
if (eax)
*eax = regs[0];
if (ebx)
*ebx = regs[1];
if (ecx)
*ecx = regs[2];
if (edx)
*edx = regs[3];
}
#endif /* i386 && GNUC */
#if defined (__x86_64__) && defined (__GNUC__)
# define HAS_X86_CPUID 1
static int
is_cpuid_available(void)
{
return 1;
}
static void
get_cpuid(unsigned int in, unsigned int *eax, unsigned int *ebx,
unsigned int *ecx, unsigned int *edx)
{
unsigned int regs[4];
asm volatile
("cpuid\n\t"
: "=a" (regs[0]), "=b" (regs[1]), "=c" (regs[2]), "=d" (regs[3])
: "0" (in)
: "cc"
);
if (eax)
*eax = regs[0];
if (ebx)
*ebx = regs[1];
if (ecx)
*ecx = regs[2];
if (edx)
*edx = regs[3];
}
#endif /* x86-64 && GNUC */
#ifdef HAS_X86_CPUID
static unsigned int
detect_x86_gnuc (void)
{
char vendor_id[12+1];
unsigned int features;
unsigned int result = 0;
if (!is_cpuid_available())
return 0;
get_cpuid(0, NULL,
(unsigned int *)&vendor_id[0],
(unsigned int *)&vendor_id[8],
(unsigned int *)&vendor_id[4]);
vendor_id[12] = 0;
if (0)
; /* Just to make "else if" and ifdef macros look pretty. */
#ifdef ENABLE_PADLOCK_SUPPORT
else if (!strcmp (vendor_id, "CentaurHauls"))
{
/* This is a VIA CPU. Check what PadLock features we have. */
/* Check for extended centaur (EAX). */
get_cpuid(0xC0000000, &features, NULL, NULL, NULL);
/* Has extended centaur features? */
if (features > 0xC0000000)
{
/* Ask for the extended feature flags (EDX). */
get_cpuid(0xC0000001, NULL, NULL, NULL, &features);
/* Test bits 2 and 3 to see whether the RNG exists and is enabled. */
if ((features & 0x0C) == 0x0C)
result |= HWF_PADLOCK_RNG;
/* Test bits 6 and 7 to see whether the ACE exists and is enabled. */
if ((features & 0xC0) == 0xC0)
result |= HWF_PADLOCK_AES;
/* Test bits 10 and 11 to see whether the PHE exists and is
enabled. */
if ((features & 0xC00) == 0xC00)
result |= HWF_PADLOCK_SHA;
/* Test bits 12 and 13 to see whether the MONTMUL exists and is
enabled. */
if ((features & 0x3000) == 0x3000)
result |= HWF_PADLOCK_MMUL;
}
}
#endif /*ENABLE_PADLOCK_SUPPORT*/
else if (!strcmp (vendor_id, "GenuineIntel"))
{
/* This is an Intel CPU. */
}
else if (!strcmp (vendor_id, "AuthenticAMD"))
{
/* This is an AMD CPU. */
}
/* Detect Intel features, that might also be supported by other
vendors. */
/* Get CPU info and Intel feature flags (ECX). */
get_cpuid(1, NULL, NULL, &features, NULL);
#ifdef ENABLE_AESNI_SUPPORT
/* Test bit 25 for AES-NI. */
if (features & 0x02000000)
result |= HWF_INTEL_AESNI;
#endif /*ENABLE_AESNI_SUPPORT*/
#ifdef ENABLE_DRNG_SUPPORT
/* Test bit 30 for RDRAND. */
if (features & 0x40000000)
result |= HWF_INTEL_RDRAND;
#endif /*ENABLE_DRNG_SUPPORT*/
return result;
}
#endif /* HAS_X86_CPUID */
unsigned int
_gcry_hwf_detect_x86 (void)
{
#if defined (HAS_X86_CPUID)
return detect_x86_gnuc ();
#else
return 0;
#endif
}

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