[PATCH v2 9/9] crypto: x86/twofish - stop using the SIMD helper

Eric Biggers
2025-04-02T00:24:45Z

From: Eric Biggers <ebiggers@google.com>

Stop wrapping skcipher and aead algorithms with the crypto SIMD helper
(crypto/simd.c). The only purpose of doing so was to work around x86
not always supporting kernel-mode FPU in softirqs. Specifically, if a
hardirq interrupted a task context kernel-mode FPU section and then a
softirqs were run at the end of that hardirq, those softirqs could not
use kernel-mode FPU. This has now been fixed. In combination with the
fact that the skcipher and aead APIs only support task and softirq
contexts, these can now just use kernel-mode FPU unconditionally on x86.

This simplifies the code and improves performance.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
arch/x86/crypto/Kconfig | 1 -
arch/x86/crypto/twofish_avx_glue.c | 21 +++++++--------------
2 files changed, 7 insertions(+), 15 deletions(-)

diff --git a/arch/x86/crypto/Kconfig b/arch/x86/crypto/Kconfig
index afc1a05e663dd..f9e46e83440f1 100644
--- a/arch/x86/crypto/Kconfig
+++ b/arch/x86/crypto/Kconfig
@@ -268,11 +268,10 @@ config CRYPTO_TWOFISH_X86_64_3WAY

config CRYPTO_TWOFISH_AVX_X86_64
tristate "Ciphers: Twofish with modes: ECB, CBC (AVX)"
depends on X86 && 64BIT
select CRYPTO_SKCIPHER
- select CRYPTO_SIMD
select CRYPTO_TWOFISH_COMMON
select CRYPTO_TWOFISH_X86_64
select CRYPTO_TWOFISH_X86_64_3WAY
imply CRYPTO_XTS
help
diff --git a/arch/x86/crypto/twofish_avx_glue.c b/arch/x86/crypto/twofish_avx_glue.c
index 3eb3440b477a8..9e20db0137501 100644
--- a/arch/x86/crypto/twofish_avx_glue.c
+++ b/arch/x86/crypto/twofish_avx_glue.c
@@ -11,11 +11,10 @@
#include <linux/module.h>
#include <linux/types.h>
#include <linux/crypto.h>
#include <linux/err.h>
#include <crypto/algapi.h>
-#include <crypto/internal/simd.h>
#include <crypto/twofish.h>

#include "twofish.h"
#include "ecb_cbc_helpers.h"

@@ -72,27 +71,25 @@ static int cbc_decrypt(struct skcipher_request *req)
CBC_WALK_END();
}

static struct skcipher_alg twofish_algs[] = {
{
- .base.cra_name = "__ecb(twofish)",
- .base.cra_driver_name = "__ecb-twofish-avx",
+ .base.cra_name = "ecb(twofish)",
+ .base.cra_driver_name = "ecb-twofish-avx",
.base.cra_priority = 400,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_blocksize = TF_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct twofish_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = TF_MIN_KEY_SIZE,
.max_keysize = TF_MAX_KEY_SIZE,
.setkey = twofish_setkey_skcipher,
.encrypt = ecb_encrypt,
.decrypt = ecb_decrypt,
}, {
- .base.cra_name = "__cbc(twofish)",
- .base.cra_driver_name = "__cbc-twofish-avx",
+ .base.cra_name = "cbc(twofish)",
+ .base.cra_driver_name = "cbc-twofish-avx",
.base.cra_priority = 400,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_blocksize = TF_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct twofish_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = TF_MIN_KEY_SIZE,
.max_keysize = TF_MAX_KEY_SIZE,
@@ -101,30 +98,26 @@ static struct skcipher_alg twofish_algs[] = {
.encrypt = cbc_encrypt,
.decrypt = cbc_decrypt,
},
};

-static struct simd_skcipher_alg *twofish_simd_algs[ARRAY_SIZE(twofish_algs)];
-
static int __init twofish_init(void)
{
const char *feature_name;

if (!cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, &feature_name)) {
pr_info("CPU feature '%s' is not supported.\n", feature_name);
return -ENODEV;
}

- return simd_register_skciphers_compat(twofish_algs,
- ARRAY_SIZE(twofish_algs),
- twofish_simd_algs);
+ return crypto_register_skciphers(twofish_algs,
+ ARRAY_SIZE(twofish_algs));
}

static void __exit twofish_exit(void)
{
- simd_unregister_skciphers(twofish_algs, ARRAY_SIZE(twofish_algs),
- twofish_simd_algs);
+ crypto_unregister_skciphers(twofish_algs, ARRAY_SIZE(twofish_algs));
}

module_init(twofish_init);
module_exit(twofish_exit);

--
2.49.0