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crypto: x86/chacha - Restore SSSE3 fallback path 

The chacha_use_simd static branch is required for x86 machines that
lack SSSE3 support.  Restore it and the generic fallback code.

Reported-by: Eric Biggers <ebiggers@kernel.org>
Fixes: 9b4400215e ("crypto: x86/chacha - Remove SIMD fallback path")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
pull/1250/head
Herbert Xu 2025-04-08 10:12:20 +08:00
parent 5322584385
commit 3be3f70ee9
1 changed files with 17 additions and 5 deletions
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22
arch/x86/crypto/chacha_glue.c
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@ -5,11 +5,12 @@
* Copyright (C) 2015 Martin Willi * Copyright (C) 2015 Martin Willi
*/ */
#include <asm/simd.h>
#include <crypto/chacha.h> #include <crypto/chacha.h>
#include <linux/jump_label.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/module.h> #include <linux/module.h>
#include <linux/sizes.h> #include <linux/sizes.h>
#include <asm/simd.h>
asmlinkage void chacha_block_xor_ssse3(u32 *state, u8 *dst, const u8 *src, asmlinkage void chacha_block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds); unsigned int len, int nrounds);
@ -31,6 +32,7 @@ asmlinkage void chacha_4block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src, asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds); unsigned int len, int nrounds);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_simd);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx2); static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx2);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx512vl); static __ro_after_init DEFINE_STATIC_KEY_FALSE(chacha_use_avx512vl);
@ -117,15 +119,23 @@ static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds) void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
{ {
kernel_fpu_begin(); if (!static_branch_likely(&chacha_use_simd)) {
hchacha_block_ssse3(state, stream, nrounds); hchacha_block_generic(state, stream, nrounds);
kernel_fpu_end(); } else {
kernel_fpu_begin();
hchacha_block_ssse3(state, stream, nrounds);
kernel_fpu_end();
}
} }
EXPORT_SYMBOL(hchacha_block_arch); EXPORT_SYMBOL(hchacha_block_arch);
void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes, void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
int nrounds) int nrounds)
{ {
if (!static_branch_likely(&chacha_use_simd) ||
bytes <= CHACHA_BLOCK_SIZE)
return chacha_crypt_generic(state, dst, src, bytes, nrounds);
do { do {
unsigned int todo = min_t(unsigned int, bytes, SZ_4K); unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
@ -142,7 +152,7 @@ EXPORT_SYMBOL(chacha_crypt_arch);
bool chacha_is_arch_optimized(void) bool chacha_is_arch_optimized(void)
{ {
return true; return static_key_enabled(&chacha_use_simd);
} }
EXPORT_SYMBOL(chacha_is_arch_optimized); EXPORT_SYMBOL(chacha_is_arch_optimized);
@ -151,6 +161,8 @@ static int __init chacha_simd_mod_init(void)
if (!boot_cpu_has(X86_FEATURE_SSSE3)) if (!boot_cpu_has(X86_FEATURE_SSSE3))
return 0; return 0;
static_branch_enable(&chacha_use_simd);
if (boot_cpu_has(X86_FEATURE_AVX) && if (boot_cpu_has(X86_FEATURE_AVX) &&
boot_cpu_has(X86_FEATURE_AVX2) && boot_cpu_has(X86_FEATURE_AVX2) &&
cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) { cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL)) {