Quelle  sha1.h   Sprache: C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * SHA-1 optimized for x86_64
 *
 * Copyright 2025 Google LLC
 */
#include <asm/fpu/api.h>
#include <linux/static_call.h>

DEFINE_STATIC_CALL(sha1_blocks_x86, sha1_blocks_generic);

#define DEFINE_X86_SHA1_FN(c_fn, asm_fn)                           \
 asmlinkage void asm_fn(struct sha1_block_state *state,     \
          const u8 *data, size_t nblocks);    \
 static void c_fn(struct sha1_block_state *state,           \
    const u8 *data, size_t nblocks)           \
 {                                                          \
  if (likely(irq_fpu_usable())) {                    \
   kernel_fpu_begin();                        \
   asm_fn(state, data, nblocks);              \
   kernel_fpu_end();                          \
  } else {                                           \
   sha1_blocks_generic(state, data, nblocks); \
  }                                                  \
 }

DEFINE_X86_SHA1_FN(sha1_blocks_ssse3, sha1_transform_ssse3);
DEFINE_X86_SHA1_FN(sha1_blocks_avx, sha1_transform_avx);
DEFINE_X86_SHA1_FN(sha1_blocks_ni, sha1_ni_transform);

#define SHA1_AVX2_BLOCK_OPTSIZE 4 /* optimal 4*64 bytes of SHA1 blocks */

asmlinkage void sha1_transform_avx2(struct sha1_block_state *state,
        const u8 *data, size_t nblocks);
static void sha1_blocks_avx2(struct sha1_block_state *state,
        const u8 *data, size_t nblocks)
{
 if (likely(irq_fpu_usable())) {
  kernel_fpu_begin();
  /* Select the optimal transform based on the number of blocks */
  if (nblocks >= SHA1_AVX2_BLOCK_OPTSIZE)
   sha1_transform_avx2(state, data, nblocks);
  else
   sha1_transform_avx(state, data, nblocks);
  kernel_fpu_end();
 } else {
  sha1_blocks_generic(state, data, nblocks);
 }
}

static void sha1_blocks(struct sha1_block_state *state,
   const u8 *data, size_t nblocks)
{
 static_call(sha1_blocks_x86)(state, data, nblocks);
}

#define sha1_mod_init_arch sha1_mod_init_arch
static inline void sha1_mod_init_arch(void)
{
 if (boot_cpu_has(X86_FEATURE_SHA_NI)) {
  static_call_update(sha1_blocks_x86, sha1_blocks_ni);
 } else if (cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM,
         NULL) &&
     boot_cpu_has(X86_FEATURE_AVX)) {
  if (boot_cpu_has(X86_FEATURE_AVX2) &&
      boot_cpu_has(X86_FEATURE_BMI1) &&
      boot_cpu_has(X86_FEATURE_BMI2))
   static_call_update(sha1_blocks_x86, sha1_blocks_avx2);
  else
   static_call_update(sha1_blocks_x86, sha1_blocks_avx);
 } else if (boot_cpu_has(X86_FEATURE_SSSE3)) {
  static_call_update(sha1_blocks_x86, sha1_blocks_ssse3);
 }
}