[PATCH 2/2] crypto: arm/aes-neonbs - stop using the SIMD helper

Ard Biesheuvel
2025-04-02T07:03:12Z

From: Ard Biesheuvel <ardb@kernel.org>

Now that ARM permits use of the NEON unit in softirq context as well as
task context, there is no longer a need to rely on the SIMD helper
module to construct async skciphers wrapping the sync ones, as the
latter can always be called directly.

So remove these wrappers and the dependency on the SIMD helper. This
permits the use of these algorithms by callers that only support
synchronous use.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/arm/crypto/Kconfig | 1 -
arch/arm/crypto/aes-neonbs-glue.c | 114 +++---------------------------
2 files changed, 9 insertions(+), 106 deletions(-)

diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig
index 2fa8aba8dc12..ba1d1b67c727 100644
--- a/arch/arm/crypto/Kconfig
+++ b/arch/arm/crypto/Kconfig
@@ -169,7 +169,6 @@ config CRYPTO_AES_ARM_BS
select CRYPTO_AES_ARM
select CRYPTO_SKCIPHER
select CRYPTO_LIB_AES
- select CRYPTO_SIMD
help
Length-preserving ciphers: AES cipher algorithms (FIPS-197)
with block cipher modes:
diff --git a/arch/arm/crypto/aes-neonbs-glue.c b/arch/arm/crypto/aes-neonbs-glue.c
index f6be80b5938b..63800257a7ea 100644
--- a/arch/arm/crypto/aes-neonbs-glue.c
+++ b/arch/arm/crypto/aes-neonbs-glue.c
@@ -59,11 +59,6 @@ struct aesbs_xts_ctx {
struct crypto_aes_ctx tweak_key;
};

-struct aesbs_ctr_ctx {
- struct aesbs_ctx key; /* must be first member */
- struct crypto_aes_ctx fallback;
-};
-
static int aesbs_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
unsigned int key_len)
{
@@ -200,25 +195,6 @@ static int cbc_decrypt(struct skcipher_request *req)
return err;
}

-static int aesbs_ctr_setkey_sync(struct crypto_skcipher *tfm, const u8 *in_key,
- unsigned int key_len)
-{
- struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
- int err;
-
- err = aes_expandkey(&ctx->fallback, in_key, key_len);
- if (err)
- return err;
-
- ctx->key.rounds = 6 + key_len / 4;
-
- kernel_neon_begin();
- aesbs_convert_key(ctx->key.rk, ctx->fallback.key_enc, ctx->key.rounds);
- kernel_neon_end();
-
- return 0;
-}
-
static int ctr_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -254,21 +230,6 @@ static int ctr_encrypt(struct skcipher_request *req)
return err;
}

-static void ctr_encrypt_one(struct crypto_skcipher *tfm, const u8 *src, u8 *dst)
-{
- struct aesbs_ctr_ctx *ctx = crypto_skcipher_ctx(tfm);
-
- __aes_arm_encrypt(ctx->fallback.key_enc, ctx->key.rounds, src, dst);
-}
-
-static int ctr_encrypt_sync(struct skcipher_request *req)
-{
- if (!crypto_simd_usable())
- return crypto_ctr_encrypt_walk(req, ctr_encrypt_one);
-
- return ctr_encrypt(req);
-}
-
static int aesbs_xts_setkey(struct crypto_skcipher *tfm, const u8 *in_key,
unsigned int key_len)
{
@@ -374,13 +335,12 @@ static int xts_decrypt(struct skcipher_request *req)
}

static struct skcipher_alg aes_algs[] = { {
- .base.cra_name = "__ecb(aes)",
- .base.cra_driver_name = "__ecb-aes-neonbs",
+ .base.cra_name = "ecb(aes)",
+ .base.cra_driver_name = "ecb-aes-neonbs",
.base.cra_priority = 250,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct aesbs_ctx),
.base.cra_module = THIS_MODULE,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,

.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
@@ -389,13 +349,12 @@ static struct skcipher_alg aes_algs[] = { {
.encrypt = ecb_encrypt,
.decrypt = ecb_decrypt,
}, {
- .base.cra_name = "__cbc(aes)",
- .base.cra_driver_name = "__cbc-aes-neonbs",
+ .base.cra_name = "cbc(aes)",
+ .base.cra_driver_name = "cbc-aes-neonbs",
.base.cra_priority = 250,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct aesbs_cbc_ctx),
.base.cra_module = THIS_MODULE,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,

.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
@@ -405,13 +364,12 @@ static struct skcipher_alg aes_algs[] = { {
.encrypt = cbc_encrypt,
.decrypt = cbc_decrypt,
}, {
- .base.cra_name = "__ctr(aes)",
- .base.cra_driver_name = "__ctr-aes-neonbs",
+ .base.cra_name = "ctr(aes)",
+ .base.cra_driver_name = "ctr-aes-neonbs",
.base.cra_priority = 250,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct aesbs_ctx),
.base.cra_module = THIS_MODULE,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,

.min_keysize = AES_MIN_KEY_SIZE,
.max_keysize = AES_MAX_KEY_SIZE,
@@ -422,29 +380,12 @@ static struct skcipher_alg aes_algs[] = { {
.encrypt = ctr_encrypt,
.decrypt = ctr_encrypt,
}, {
- .base.cra_name = "ctr(aes)",
- .base.cra_driver_name = "ctr-aes-neonbs-sync",
- .base.cra_priority = 250 - 1,
- .base.cra_blocksize = 1,
- .base.cra_ctxsize = sizeof(struct aesbs_ctr_ctx),
- .base.cra_module = THIS_MODULE,
-
- .min_keysize = AES_MIN_KEY_SIZE,
- .max_keysize = AES_MAX_KEY_SIZE,
- .chunksize = AES_BLOCK_SIZE,
- .walksize = 8 * AES_BLOCK_SIZE,
- .ivsize = AES_BLOCK_SIZE,
- .setkey = aesbs_ctr_setkey_sync,
- .encrypt = ctr_encrypt_sync,
- .decrypt = ctr_encrypt_sync,
-}, {
- .base.cra_name = "__xts(aes)",
- .base.cra_driver_name = "__xts-aes-neonbs",
+ .base.cra_name = "xts(aes)",
+ .base.cra_driver_name = "xts-aes-neonbs",
.base.cra_priority = 250,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct aesbs_xts_ctx),
.base.cra_module = THIS_MODULE,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,

.min_keysize = 2 * AES_MIN_KEY_SIZE,
.max_keysize = 2 * AES_MAX_KEY_SIZE,
@@ -455,54 +396,17 @@ static struct skcipher_alg aes_algs[] = { {
.decrypt = xts_decrypt,
} };

-static struct simd_skcipher_alg *aes_simd_algs[ARRAY_SIZE(aes_algs)];
-
static void aes_exit(void)
{
- int i;
-
- for (i = 0; i < ARRAY_SIZE(aes_simd_algs); i++)
- if (aes_simd_algs[i])
- simd_skcipher_free(aes_simd_algs[i]);
-
crypto_unregister_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
}

static int __init aes_init(void)
{
- struct simd_skcipher_alg *simd;
- const char *basename;
- const char *algname;
- const char *drvname;
- int err;
- int i;
-
if (!(elf_hwcap & HWCAP_NEON))
return -ENODEV;

- err = crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
- if (err)
- return err;
-
- for (i = 0; i < ARRAY_SIZE(aes_algs); i++) {
- if (!(aes_algs[i].base.cra_flags & CRYPTO_ALG_INTERNAL))
- continue;
-
- algname = aes_algs[i].base.cra_name + 2;
- drvname = aes_algs[i].base.cra_driver_name + 2;
- basename = aes_algs[i].base.cra_driver_name;
- simd = simd_skcipher_create_compat(aes_algs + i, algname, drvname, basename);
- err = PTR_ERR(simd);
- if (IS_ERR(simd))
- goto unregister_simds;
-
- aes_simd_algs[i] = simd;
- }
- return 0;
-
-unregister_simds:
- aes_exit();
- return err;
+ return crypto_register_skciphers(aes_algs, ARRAY_SIZE(aes_algs));
}

late_initcall(aes_init);
--
2.49.0.472.ge94155a9ec-goog