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/*
* Copyright 1998-2022 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "internal/e_os.h"
#include "crypto/cryptlib.h"
#if defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
defined(__x86_64) || defined(__x86_64__) || \
defined(_M_AMD64) || defined(_M_X64)
extern unsigned int OPENSSL_ia32cap_P[4];
# if defined(OPENSSL_CPUID_OBJ)
/*
* Purpose of these minimalistic and character-type-agnostic subroutines
* is to break dependency on MSVCRT (on Windows) and locale. This makes
* OPENSSL_cpuid_setup safe to use as "constructor". "Character-type-
* agnostic" means that they work with either wide or 8-bit characters,
* exploiting the fact that first 127 characters can be simply casted
* between the sets, while the rest would be simply rejected by ossl_is*
* subroutines.
*/
# ifdef _WIN32
typedef WCHAR variant_char;
static variant_char *ossl_getenv(const char *name)
{
/*
* Since we pull only one environment variable, it's simpler to
* just ignore |name| and use equivalent wide-char L-literal.
* As well as to ignore excessively long values...
*/
static WCHAR value[48];
DWORD len = GetEnvironmentVariableW(L"OPENSSL_ia32cap", value, 48);
return (len > 0 && len < 48) ? value : NULL;
}
# else
typedef char variant_char;
# define ossl_getenv getenv
# endif
# include "crypto/ctype.h"
static int todigit(variant_char c)
{
if (ossl_isdigit(c))
return c - '0';
else if (ossl_isxdigit(c))
return ossl_tolower(c) - 'a' + 10;
/* return largest base value to make caller terminate the loop */
return 16;
}
static uint64_t ossl_strtouint64(const variant_char *str)
{
uint64_t ret = 0;
unsigned int digit, base = 10;
if (*str == '0') {
base = 8, str++;
if (ossl_tolower(*str) == 'x')
base = 16, str++;
}
while ((digit = todigit(*str++)) < base)
ret = ret * base + digit;
return ret;
}
static variant_char *ossl_strchr(const variant_char *str, char srch)
{ variant_char c;
while ((c = *str)) {
if (c == srch)
return (variant_char *)str;
str++;
}
return NULL;
}
# define OPENSSL_CPUID_SETUP
typedef uint64_t IA32CAP;
void OPENSSL_cpuid_setup(void)
{
static int trigger = 0;
IA32CAP OPENSSL_ia32_cpuid(unsigned int *);
IA32CAP vec;
const variant_char *env;
if (trigger)
return;
trigger = 1;
if ((env = ossl_getenv("OPENSSL_ia32cap")) != NULL) {
int off = (env[0] == '~') ? 1 : 0;
vec = ossl_strtouint64(env + off);
if (off) {
IA32CAP mask = vec;
vec = OPENSSL_ia32_cpuid(OPENSSL_ia32cap_P) & ~mask;
if (mask & (1<<24)) {
/*
* User disables FXSR bit, mask even other capabilities
* that operate exclusively on XMM, so we don't have to
* double-check all the time. We mask PCLMULQDQ, AMD XOP,
* AES-NI and AVX. Formally speaking we don't have to
* do it in x86_64 case, but we can safely assume that
* x86_64 users won't actually flip this flag.
*/
vec &= ~((IA32CAP)(1<<1|1<<11|1<<25|1<<28) << 32);
}
} else if (env[0] == ':') {
vec = OPENSSL_ia32_cpuid(OPENSSL_ia32cap_P);
}
if ((env = ossl_strchr(env, ':')) != NULL) {
IA32CAP vecx;
env++;
off = (env[0] == '~') ? 1 : 0;
vecx = ossl_strtouint64(env + off);
if (off) {
OPENSSL_ia32cap_P[2] &= ~(unsigned int)vecx;
OPENSSL_ia32cap_P[3] &= ~(unsigned int)(vecx >> 32);
} else {
OPENSSL_ia32cap_P[2] = (unsigned int)vecx;
OPENSSL_ia32cap_P[3] = (unsigned int)(vecx >> 32);
}
} else {
OPENSSL_ia32cap_P[2] = 0;
OPENSSL_ia32cap_P[3] = 0;
}
} else {
vec = OPENSSL_ia32_cpuid(OPENSSL_ia32cap_P);
}
/*
* |(1<<10) sets a reserved bit to signal that variable
* was initialized already... This is to avoid interference
* with cpuid snippets in ELF .init segment.
*/
OPENSSL_ia32cap_P[0] = (unsigned int)vec | (1 << 10);
OPENSSL_ia32cap_P[1] = (unsigned int)(vec >> 32);
}
# else
unsigned int OPENSSL_ia32cap_P[4];
# endif
#endif
#ifndef OPENSSL_CPUID_OBJ
# ifndef OPENSSL_CPUID_SETUP
void OPENSSL_cpuid_setup(void)
{
}
# endif
/*
* The rest are functions that are defined in the same assembler files as
* the CPUID functionality.
*/
/*
* The volatile is used to ensure that the compiler generates code that reads
* all values from the array and doesn't try to optimize this away. The standard
* doesn't actually require this behavior if the original data pointed to is
* not volatile, but compilers do this in practice anyway.
*
* There are also assembler versions of this function.
*/
# undef CRYPTO_memcmp
int CRYPTO_memcmp(const void *in_a, const void *in_b, size_t len)
{
size_t i;
const volatile unsigned char *a = in_a;
const volatile unsigned char *b = in_b;
unsigned char x = 0;
for (i = 0; i < len; i++)
x |= a[i] ^ b[i];
return x;
}
/*
* For systems that don't provide an instruction counter register or equivalent.
*/
uint32_t OPENSSL_rdtsc(void)
{
return 0;
}
size_t OPENSSL_instrument_bus(unsigned int *out, size_t cnt)
{
return 0;
}
size_t OPENSSL_instrument_bus2(unsigned int *out, size_t cnt, size_t max)
{
return 0;
}
#endif
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