/*

 * Copyright 1998-2023 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