xref: /external/chromium_org/third_party/boringssl/src/crypto/cpu-intel.c

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.] */

#if !defined(__STDC_FORMAT_MACROS)
#define __STDC_FORMAT_MACROS
#endif

#include <openssl/cpu.h>


#if !defined(OPENSSL_NO_ASM) && (defined(OPENSSL_X86) || defined(OPENSSL_X86_64))

#include <stdio.h>
#include <inttypes.h>

/* This value must be explicitly initialised to zero in order to work around a
 * bug in libtool or the linker on OS X.
 *
 * If not initialised then it becomes a "common symbol". When put into an
 * archive, linking on OS X will fail to resolve common symbols. By
 * initialising it to zero, it becomes a "data symbol", which isn't so
 * affected. */
uint32_t OPENSSL_ia32cap_P[4] = {0};

/* OPENSSL_ia32_cpuid is defined in cpu-x86_64-asm.pl. */
extern uint64_t OPENSSL_ia32_cpuid(uint32_t*);

/* handle_cpu_env applies the value from |in| to the CPUID values in |out[0]|
 * and |out[1]|. See the comment in |OPENSSL_cpuid_setup| about this. */
static void handle_cpu_env(uint32_t *out, const char *in) {
  const int invert = in[0] == '~';
  uint64_t v;

  if (!sscanf(in + invert, "%" PRIi64, &v)) {
    return;
  }

  if (invert) {
    out[0] &= ~v;
    out[1] &= ~(v >> 32);
  } else {
    out[0] = v;
    out[1] = v >> 32;
  }
}

void OPENSSL_cpuid_setup(void) {
  const char *env1, *env2;

#if defined(OPENSSL_X86_64)
  OPENSSL_ia32_cpuid(OPENSSL_ia32cap_P);
#else
  uint64_t vec = OPENSSL_ia32_cpuid(OPENSSL_ia32cap_P);
  /* 1<<10 sets a reserved bit to indicate that the variable
   * was already initialised. */
  OPENSSL_ia32cap_P[0] = ((uint32_t)vec) | (1 << 10);
  OPENSSL_ia32cap_P[1] = vec >> 32;
#endif

  env1 = getenv("OPENSSL_ia32cap");
  if (env1 == NULL) {
    return;
  }

  /* OPENSSL_ia32cap can contain zero, one or two values, separated with a ':'.
   * Each value is a 64-bit, unsigned value which may start with "0x" to
   * indicate a hex value. Prior to the 64-bit value, a '~' may be given.
   *
   * If '~' isn't present, then the value is taken as the result of the CPUID.
   * Otherwise the value is inverted and ANDed with the probed CPUID result.
   *
   * The first value determines OPENSSL_ia32cap_P[0] and [1]. The second [2]
   * and [3]. */

  handle_cpu_env(&OPENSSL_ia32cap_P[0], env1);
  env2 = strchr(env1, ':');
  if (env2 != NULL) {
    handle_cpu_env(&OPENSSL_ia32cap_P[2], env2 + 1);
  }
}

#endif  /* !OPENSSL_NO_ASM && (OPENSSL_X86 || OPENSSL_X86_64) */