/* 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.] */

#include <ring-core/base.h>

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

#if defined(_MSC_VER) && !defined(__clang__)

#pragma warning(push, 3)

#include <immintrin.h>

#include <intrin.h>

#pragma warning(pop)

#endif

#include "internal.h"

// OPENSSL_cpuid runs the cpuid instruction. |leaf| is passed in as EAX and ECX

// is set to zero. It writes EAX, EBX, ECX, and EDX to |*out_eax| through

// |*out_edx|.

static void OPENSSL_cpuid(uint32_t *out_eax, uint32_t *out_ebx,

                          uint32_t *out_ecx, uint32_t *out_edx, uint32_t leaf) {

#if defined(_MSC_VER) && !defined(__clang__)

  int tmp[4];

  __cpuid(tmp, (int)leaf);

  *out_eax = (uint32_t)tmp[0];

  *out_ebx = (uint32_t)tmp[1];

  *out_ecx = (uint32_t)tmp[2];

  *out_edx = (uint32_t)tmp[3];

#elif defined(__pic__) && defined(OPENSSL_32_BIT)

  // Inline assembly may not clobber the PIC register. For 32-bit, this is EBX.

  // See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=47602.

  __asm__ volatile (

    "xor %%ecx, %%ecx\n"

    "mov %%ebx, %%edi\n"

    "cpuid\n"

    "xchg %%edi, %%ebx\n"

    : "=a"(*out_eax), "=D"(*out_ebx), "=c"(*out_ecx), "=d"(*out_edx)

    : "a"(leaf)

  );

#else

  __asm__ volatile (

    "xor %%ecx, %%ecx\n"

    "cpuid\n"

    : "=a"(*out_eax), "=b"(*out_ebx), "=c"(*out_ecx), "=d"(*out_edx)

    : "a"(leaf)

  );

#endif

}

// OPENSSL_xgetbv returns the value of an Intel Extended Control Register (XCR).

// Currently only XCR0 is defined by Intel so |xcr| should always be zero.

//

// See https://software.intel.com/en-us/articles/how-to-detect-new-instruction-support-in-the-4th-generation-intel-core-processor-family

static uint64_t OPENSSL_xgetbv(uint32_t xcr) {

#if defined(_MSC_VER) && !defined(__clang__)

  return (uint64_t)_xgetbv(xcr);

#else

  uint32_t eax, edx;

  __asm__ volatile ("xgetbv" : "=a"(eax), "=d"(edx) : "c"(xcr));

  return (((uint64_t)edx) << 32) | eax;

#endif

}

void OPENSSL_cpuid_setup(void) {

  // Determine the vendor and maximum input value.

  uint32_t eax, ebx, ecx, edx;

  OPENSSL_cpuid(&eax, &ebx, &ecx, &edx, 0);

  uint32_t num_ids = eax;

  int is_intel = ebx == 0x756e6547 /* Genu */ &&

                 edx == 0x49656e69 /* ineI */ &&

                 ecx == 0x6c65746e /* ntel */;

  uint32_t extended_features[2] = {0};

  if (num_ids >= 7) {

    OPENSSL_cpuid(&eax, &ebx, &ecx, &edx, 7);

    extended_features[0] = ebx;

    extended_features[1] = ecx;

  }

  OPENSSL_cpuid(&eax, &ebx, &ecx, &edx, 1);

  // Force the hyper-threading bit so that the more conservative path is always

  // chosen.

  edx |= 1u << 28;

  // Reserved bit #20 was historically repurposed to control the in-memory

  // representation of RC4 state. Always set it to zero.

  edx &= ~(1u << 20);

  // Reserved bit #30 is repurposed to signal an Intel CPU.

  if (is_intel) {

    edx |= (1u << 30);

    // Clear the XSAVE bit on Knights Landing to mimic Silvermont. This enables

    // some Silvermont-specific codepaths which perform better. See OpenSSL

    // commit 64d92d74985ebb3d0be58a9718f9e080a14a8e7f.

    if ((eax & 0x0fff0ff0) == 0x00050670 /* Knights Landing */ ||

        (eax & 0x0fff0ff0) == 0x00080650 /* Knights Mill (per SDE) */) {

      ecx &= ~(1u << 26);

    }

  } else {

    edx &= ~(1u << 30);

  }

  // The SDBG bit is repurposed to denote AMD XOP support. Don't ever use AMD

  // XOP code paths.

  ecx &= ~(1u << 11);

  uint64_t xcr0 = 0;

  if (ecx & (1u << 27)) {

    // XCR0 may only be queried if the OSXSAVE bit is set.

    xcr0 = OPENSSL_xgetbv(0);

  }

  // See Intel manual, volume 1, section 14.3.

  if ((xcr0 & 6) != 6) {

    // YMM registers cannot be used.

    ecx &= ~(1u << 28);  // AVX

    ecx &= ~(1u << 12);  // FMA

    ecx &= ~(1u << 11);  // AMD XOP

    // Clear AVX2 and AVX512* bits.

    //

    // TODO(davidben): Should bits 17 and 26-28 also be cleared? Upstream

    // doesn't clear those.

    extended_features[0] &=

        ~((1u << 5) | (1u << 16) | (1u << 21) | (1u << 30) | (1u << 31));

  }

  // See Intel manual, volume 1, section 15.2.

  if ((xcr0 & 0xe6) != 0xe6) {

    // Clear AVX512F. Note we don't touch other AVX512 extensions because they

    // can be used with YMM.

    extended_features[0] &= ~(1u << 16);

  }

  // Disable ADX instructions on Knights Landing. See OpenSSL commit

  // 64d92d74985ebb3d0be58a9718f9e080a14a8e7f.

  if ((ecx & (1u << 26)) == 0) {

    extended_features[0] &= ~(1u << 19);

  }

  OPENSSL_ia32cap_P[0] = edx;

  OPENSSL_ia32cap_P[1] = ecx;

  OPENSSL_ia32cap_P[2] = extended_features[0];

  OPENSSL_ia32cap_P[3] = extended_features[1];

}

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