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9f97707bdb
Instead of having both sha256_blocks_arch() and sha256_blocks_simd(), instead have just sha256_blocks_arch() which uses the most efficient implementation that is available in the calling context. This is simpler, as it reduces the API surface. It's also safer, since sha256_blocks_arch() just works in all contexts, including contexts where the FPU/SIMD/vector registers cannot be used. This doesn't mean that SHA-256 computations *should* be done in such contexts, but rather we should just do the right thing instead of corrupting a random task's registers. Eliminating this footgun and simplifying the code is well worth the very small performance cost of doing the check. Note: in the case of arm and arm64, what used to be sha256_blocks_arch() is renamed back to its original name of sha256_block_data_order(). sha256_blocks_arch() is now used for the higher-level dispatch function. This renaming also required an update to lib/crypto/arm64/sha512.h, since sha2-armv8.pl is shared by both SHA-256 and SHA-512. Acked-by: Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20250630160645.3198-5-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@kernel.org>
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later */
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/*
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* arm64-optimized SHA-512 block function
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*
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* Copyright 2025 Google LLC
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*/
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#include <asm/neon.h>
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#include <crypto/internal/simd.h>
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#include <linux/cpufeature.h>
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static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_sha512_insns);
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asmlinkage void sha512_block_data_order(struct sha512_block_state *state,
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const u8 *data, size_t nblocks);
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asmlinkage size_t __sha512_ce_transform(struct sha512_block_state *state,
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const u8 *data, size_t nblocks);
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static void sha512_blocks(struct sha512_block_state *state,
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const u8 *data, size_t nblocks)
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{
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if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
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static_branch_likely(&have_sha512_insns) &&
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likely(crypto_simd_usable())) {
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do {
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size_t rem;
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kernel_neon_begin();
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rem = __sha512_ce_transform(state, data, nblocks);
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kernel_neon_end();
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data += (nblocks - rem) * SHA512_BLOCK_SIZE;
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nblocks = rem;
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} while (nblocks);
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} else {
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sha512_block_data_order(state, data, nblocks);
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}
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}
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#ifdef CONFIG_KERNEL_MODE_NEON
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#define sha512_mod_init_arch sha512_mod_init_arch
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static inline void sha512_mod_init_arch(void)
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{
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if (cpu_have_named_feature(SHA512))
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static_branch_enable(&have_sha512_insns);
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}
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#endif /* CONFIG_KERNEL_MODE_NEON */
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