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/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* SHA-256 optimized for ARM64
*
* Copyright 2025 Google LLC
*/
#include <asm/neon.h>
#include <asm/simd.h>
#include <linux/cpufeature.h>
static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_ce);
asmlinkage void sha256_block_data_order(struct sha256_block_state *state,
const u8 *data, size_t nblocks);
asmlinkage void sha256_block_neon(struct sha256_block_state *state,
const u8 *data, size_t nblocks);
asmlinkage size_t __sha256_ce_transform(struct sha256_block_state *state,
const u8 *data, size_t nblocks);
static void sha256_blocks(struct sha256_block_state *state,
const u8 *data, size_t nblocks)
{
if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
static_branch_likely(&have_neon) && likely(may_use_simd())) {
if (static_branch_likely(&have_ce)) {
do {
size_t rem;
kernel_neon_begin();
rem = __sha256_ce_transform(state,
data, nblocks);
kernel_neon_end();
data += (nblocks - rem) * SHA256_BLOCK_SIZE;
nblocks = rem;
} while (nblocks);
} else {
kernel_neon_begin();
sha256_block_neon(state, data, nblocks);
kernel_neon_end();
}
} else {
sha256_block_data_order(state, data, nblocks);
}
}
static_assert(offsetof(struct __sha256_ctx, state) == 0);
static_assert(offsetof(struct __sha256_ctx, bytecount) == 32);
static_assert(offsetof(struct __sha256_ctx, buf) == 40);
asmlinkage void sha256_ce_finup2x(const struct __sha256_ctx *ctx,
const u8 *data1, const u8 *data2, int len,
u8 out1[SHA256_DIGEST_SIZE],
u8 out2[SHA256_DIGEST_SIZE]);
#define sha256_finup_2x_arch sha256_finup_2x_arch
static bool sha256_finup_2x_arch(const struct __sha256_ctx *ctx,
const u8 *data1, const u8 *data2, size_t len,
u8 out1[SHA256_DIGEST_SIZE],
u8 out2[SHA256_DIGEST_SIZE])
{
/*
* The assembly requires len >= SHA256_BLOCK_SIZE && len <= INT_MAX.
* Further limit len to 65536 to avoid spending too long with preemption
* disabled. (Of course, in practice len is nearly always 4096 anyway.)
*/
if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
static_branch_likely(&have_ce) && len >= SHA256_BLOCK_SIZE &&
len <= 65536 && likely(may_use_simd())) {
kernel_neon_begin();
sha256_ce_finup2x(ctx, data1, data2, len, out1, out2);
kernel_neon_end();
kmsan_unpoison_memory(out1, SHA256_DIGEST_SIZE);
kmsan_unpoison_memory(out2, SHA256_DIGEST_SIZE);
return true;
}
return false;
}
static bool sha256_finup_2x_is_optimized_arch(void)
{
return static_key_enabled(&have_ce);
}
#ifdef CONFIG_KERNEL_MODE_NEON
#define sha256_mod_init_arch sha256_mod_init_arch
static void sha256_mod_init_arch(void)
{
if (cpu_have_named_feature(ASIMD)) {
static_branch_enable(&have_neon);
if (cpu_have_named_feature(SHA2))
static_branch_enable(&have_ce);
}
}
#endif /* CONFIG_KERNEL_MODE_NEON */
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