[PATCH 1/2] crypto: arm/aes-ce - stop using the SIMD helper

Ard Biesheuvel
2025-04-02T07:03:10Z

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-ce-glue.c | 102 ++++------------------------------
2 files changed, 11 insertions(+), 92 deletions(-)

diff --git a/arch/arm/crypto/Kconfig b/arch/arm/crypto/Kconfig
index 32650c8431d9..2fa8aba8dc12 100644
--- a/arch/arm/crypto/Kconfig
+++ b/arch/arm/crypto/Kconfig
@@ -197,7 +197,6 @@ config CRYPTO_AES_ARM_CE
depends on KERNEL_MODE_NEON
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-ce-glue.c b/arch/arm/crypto/aes-ce-glue.c
index 21df5e7f51f9..c17d9e4ad8e6 100644
--- a/arch/arm/crypto/aes-ce-glue.c
+++ b/arch/arm/crypto/aes-ce-glue.c
@@ -418,29 +418,6 @@ 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 crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
- unsigned long flags;
-
- /*
- * Temporarily disable interrupts to avoid races where
- * cachelines are evicted when the CPU is interrupted
- * to do something else.
- */
- local_irq_save(flags);
- aes_encrypt(ctx, dst, src);
- local_irq_restore(flags);
-}
-
-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 xts_encrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -586,10 +563,9 @@ 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-ce",
+ .base.cra_name = "ecb(aes)",
+ .base.cra_driver_name = "ecb-aes-ce",
.base.cra_priority = 300,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
.base.cra_module = THIS_MODULE,
@@ -600,10 +576,9 @@ static struct skcipher_alg aes_algs[] = { {
.encrypt = ecb_encrypt,
.decrypt = ecb_decrypt,
}, {
- .base.cra_name = "__cbc(aes)",
- .base.cra_driver_name = "__cbc-aes-ce",
+ .base.cra_name = "cbc(aes)",
+ .base.cra_driver_name = "cbc-aes-ce",
.base.cra_priority = 300,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
.base.cra_module = THIS_MODULE,
@@ -615,10 +590,9 @@ static struct skcipher_alg aes_algs[] = { {
.encrypt = cbc_encrypt,
.decrypt = cbc_decrypt,
}, {
- .base.cra_name = "__cts(cbc(aes))",
- .base.cra_driver_name = "__cts-cbc-aes-ce",
+ .base.cra_name = "cts(cbc(aes))",
+ .base.cra_driver_name = "cts-cbc-aes-ce",
.base.cra_priority = 300,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
.base.cra_module = THIS_MODULE,
@@ -631,10 +605,9 @@ static struct skcipher_alg aes_algs[] = { {
.encrypt = cts_cbc_encrypt,
.decrypt = cts_cbc_decrypt,
}, {
- .base.cra_name = "__ctr(aes)",
- .base.cra_driver_name = "__ctr-aes-ce",
+ .base.cra_name = "ctr(aes)",
+ .base.cra_driver_name = "ctr-aes-ce",
.base.cra_priority = 300,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
.base.cra_module = THIS_MODULE,
@@ -647,25 +620,9 @@ static struct skcipher_alg aes_algs[] = { {
.encrypt = ctr_encrypt,
.decrypt = ctr_encrypt,
}, {
- .base.cra_name = "ctr(aes)",
- .base.cra_driver_name = "ctr-aes-ce-sync",
- .base.cra_priority = 300 - 1,
- .base.cra_blocksize = 1,
- .base.cra_ctxsize = sizeof(struct crypto_aes_ctx),
- .base.cra_module = THIS_MODULE,
-
- .min_keysize = AES_MIN_KEY_SIZE,
- .max_keysize = AES_MAX_KEY_SIZE,
- .ivsize = AES_BLOCK_SIZE,
- .chunksize = AES_BLOCK_SIZE,
- .setkey = ce_aes_setkey,
- .encrypt = ctr_encrypt_sync,
- .decrypt = ctr_encrypt_sync,
-}, {
- .base.cra_name = "__xts(aes)",
- .base.cra_driver_name = "__xts-aes-ce",
+ .base.cra_name = "xts(aes)",
+ .base.cra_driver_name = "xts-aes-ce",
.base.cra_priority = 300,
- .base.cra_flags = CRYPTO_ALG_INTERNAL,
.base.cra_blocksize = AES_BLOCK_SIZE,
.base.cra_ctxsize = sizeof(struct crypto_aes_xts_ctx),
.base.cra_module = THIS_MODULE,
@@ -679,51 +636,14 @@ 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) && aes_simd_algs[i]; 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;
-
- 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));
}

module_cpu_feature_match(AES, aes_init);
--
2.49.0.472.ge94155a9ec-goog