* [PATCH] crypto: inside-secure - remove crc32 support
@ 2025-05-31 20:42 Eric Biggers
2025-06-01 9:03 ` Ard Biesheuvel
2025-06-08 23:41 ` Eric Biggers
0 siblings, 2 replies; 3+ messages in thread
From: Eric Biggers @ 2025-05-31 20:42 UTC (permalink / raw)
To: linux-kernel; +Cc: linux-crypto, Ard Biesheuvel, Antoine Tenart
From: Eric Biggers <ebiggers@google.com>
The crc32 acceleration in the inside-secure driver is accessible only as
an asynchronous hash. However, there seems to be no corresponding user
of crc32 in the kernel that supports asynchronous hashes. Therefore,
this code seems to be unused.
The patch that added this code provided no justification for its
inclusion. All devicetree bindings for this accelerator are for arm64;
arm64 CPUs often have CRC or PMULL instructions, which already
accelerate crc32 very well. And these actually work with the crc32
users in the kernel, unlike this driver which doesn't.
Remove this unnecessary code.
Cc: Antoine Tenart <atenart@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
---
I'm planning to take this patch via the crc tree.
drivers/crypto/inside-secure/safexcel.c | 1 -
drivers/crypto/inside-secure/safexcel.h | 1 -
drivers/crypto/inside-secure/safexcel_hash.c | 92 +-------------------
3 files changed, 2 insertions(+), 92 deletions(-)
diff --git a/drivers/crypto/inside-secure/safexcel.c b/drivers/crypto/inside-secure/safexcel.c
index 9ca80d082c4fb..c3b2b22934b7e 100644
--- a/drivers/crypto/inside-secure/safexcel.c
+++ b/drivers/crypto/inside-secure/safexcel.c
@@ -1216,11 +1216,10 @@ static struct safexcel_alg_template *safexcel_algs[] = {
&safexcel_alg_authenc_hmac_sha384_ctr_aes,
&safexcel_alg_authenc_hmac_sha512_ctr_aes,
&safexcel_alg_xts_aes,
&safexcel_alg_gcm,
&safexcel_alg_ccm,
- &safexcel_alg_crc32,
&safexcel_alg_cbcmac,
&safexcel_alg_xcbcmac,
&safexcel_alg_cmac,
&safexcel_alg_chacha20,
&safexcel_alg_chachapoly,
diff --git a/drivers/crypto/inside-secure/safexcel.h b/drivers/crypto/inside-secure/safexcel.h
index 0c79ad78d1c0a..0f27367a85fa2 100644
--- a/drivers/crypto/inside-secure/safexcel.h
+++ b/drivers/crypto/inside-secure/safexcel.h
@@ -957,11 +957,10 @@ extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha256_ctr_aes;
extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha384_ctr_aes;
extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha512_ctr_aes;
extern struct safexcel_alg_template safexcel_alg_xts_aes;
extern struct safexcel_alg_template safexcel_alg_gcm;
extern struct safexcel_alg_template safexcel_alg_ccm;
-extern struct safexcel_alg_template safexcel_alg_crc32;
extern struct safexcel_alg_template safexcel_alg_cbcmac;
extern struct safexcel_alg_template safexcel_alg_xcbcmac;
extern struct safexcel_alg_template safexcel_alg_cmac;
extern struct safexcel_alg_template safexcel_alg_chacha20;
extern struct safexcel_alg_template safexcel_alg_chachapoly;
diff --git a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c
index d2b632193bebb..fd34dc8f5707d 100644
--- a/drivers/crypto/inside-secure/safexcel_hash.c
+++ b/drivers/crypto/inside-secure/safexcel_hash.c
@@ -287,18 +287,12 @@ static int safexcel_handle_req_result(struct safexcel_crypto_priv *priv,
*should_complete = false; /* Not done yet */
return 1;
}
- if (unlikely(sreq->digest == CONTEXT_CONTROL_DIGEST_XCM &&
- ctx->alg == CONTEXT_CONTROL_CRYPTO_ALG_CRC32)) {
- /* Undo final XOR with 0xffffffff ...*/
- *(__le32 *)areq->result = ~sreq->state[0];
- } else {
- memcpy(areq->result, sreq->state,
- crypto_ahash_digestsize(ahash));
- }
+ memcpy(areq->result, sreq->state,
+ crypto_ahash_digestsize(ahash));
}
cache_len = safexcel_queued_len(sreq);
if (cache_len)
memcpy(sreq->cache, sreq->cache_next, cache_len);
@@ -1879,92 +1873,10 @@ struct safexcel_alg_template safexcel_alg_hmac_md5 = {
},
},
},
};
-static int safexcel_crc32_cra_init(struct crypto_tfm *tfm)
-{
- struct safexcel_ahash_ctx *ctx = crypto_tfm_ctx(tfm);
- int ret = safexcel_ahash_cra_init(tfm);
-
- /* Default 'key' is all zeroes */
- memset(&ctx->base.ipad, 0, sizeof(u32));
- return ret;
-}
-
-static int safexcel_crc32_init(struct ahash_request *areq)
-{
- struct safexcel_ahash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(areq));
- struct safexcel_ahash_req *req = ahash_request_ctx_dma(areq);
-
- memset(req, 0, sizeof(*req));
-
- /* Start from loaded key */
- req->state[0] = cpu_to_le32(~ctx->base.ipad.word[0]);
- /* Set processed to non-zero to enable invalidation detection */
- req->len = sizeof(u32);
- req->processed = sizeof(u32);
-
- ctx->alg = CONTEXT_CONTROL_CRYPTO_ALG_CRC32;
- req->digest = CONTEXT_CONTROL_DIGEST_XCM;
- req->state_sz = sizeof(u32);
- req->digest_sz = sizeof(u32);
- req->block_sz = sizeof(u32);
-
- return 0;
-}
-
-static int safexcel_crc32_setkey(struct crypto_ahash *tfm, const u8 *key,
- unsigned int keylen)
-{
- struct safexcel_ahash_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
-
- if (keylen != sizeof(u32))
- return -EINVAL;
-
- memcpy(&ctx->base.ipad, key, sizeof(u32));
- return 0;
-}
-
-static int safexcel_crc32_digest(struct ahash_request *areq)
-{
- return safexcel_crc32_init(areq) ?: safexcel_ahash_finup(areq);
-}
-
-struct safexcel_alg_template safexcel_alg_crc32 = {
- .type = SAFEXCEL_ALG_TYPE_AHASH,
- .algo_mask = 0,
- .alg.ahash = {
- .init = safexcel_crc32_init,
- .update = safexcel_ahash_update,
- .final = safexcel_ahash_final,
- .finup = safexcel_ahash_finup,
- .digest = safexcel_crc32_digest,
- .setkey = safexcel_crc32_setkey,
- .export = safexcel_ahash_export,
- .import = safexcel_ahash_import,
- .halg = {
- .digestsize = sizeof(u32),
- .statesize = sizeof(struct safexcel_ahash_export_state),
- .base = {
- .cra_name = "crc32",
- .cra_driver_name = "safexcel-crc32",
- .cra_priority = SAFEXCEL_CRA_PRIORITY,
- .cra_flags = CRYPTO_ALG_OPTIONAL_KEY |
- CRYPTO_ALG_ASYNC |
- CRYPTO_ALG_ALLOCATES_MEMORY |
- CRYPTO_ALG_KERN_DRIVER_ONLY,
- .cra_blocksize = 1,
- .cra_ctxsize = sizeof(struct safexcel_ahash_ctx),
- .cra_init = safexcel_crc32_cra_init,
- .cra_exit = safexcel_ahash_cra_exit,
- .cra_module = THIS_MODULE,
- },
- },
- },
-};
-
static int safexcel_cbcmac_init(struct ahash_request *areq)
{
struct safexcel_ahash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(areq));
struct safexcel_ahash_req *req = ahash_request_ctx_dma(areq);
base-commit: 4cb6c8af8591135ec000fbe4bb474139ceec595d
--
2.49.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] crypto: inside-secure - remove crc32 support
2025-05-31 20:42 [PATCH] crypto: inside-secure - remove crc32 support Eric Biggers
@ 2025-06-01 9:03 ` Ard Biesheuvel
2025-06-08 23:41 ` Eric Biggers
1 sibling, 0 replies; 3+ messages in thread
From: Ard Biesheuvel @ 2025-06-01 9:03 UTC (permalink / raw)
To: Eric Biggers; +Cc: linux-kernel, linux-crypto, Antoine Tenart
On Sat, 31 May 2025 at 22:43, Eric Biggers <ebiggers@kernel.org> wrote:
>
> From: Eric Biggers <ebiggers@google.com>
>
> The crc32 acceleration in the inside-secure driver is accessible only as
> an asynchronous hash. However, there seems to be no corresponding user
> of crc32 in the kernel that supports asynchronous hashes. Therefore,
> this code seems to be unused.
>
> The patch that added this code provided no justification for its
> inclusion. All devicetree bindings for this accelerator are for arm64;
> arm64 CPUs often have CRC or PMULL instructions, which already
> accelerate crc32 very well. And these actually work with the crc32
> users in the kernel, unlike this driver which doesn't.
>
CRC instructions are mandatory in the ARM architecture revision v8.1,
and the only known core that does not implement them is the long
obsolete APM X-Gene.
> Remove this unnecessary code.
>
> Cc: Antoine Tenart <atenart@kernel.org>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
> ---
>
> I'm planning to take this patch via the crc tree.
>
> drivers/crypto/inside-secure/safexcel.c | 1 -
> drivers/crypto/inside-secure/safexcel.h | 1 -
> drivers/crypto/inside-secure/safexcel_hash.c | 92 +-------------------
> 3 files changed, 2 insertions(+), 92 deletions(-)
>
> diff --git a/drivers/crypto/inside-secure/safexcel.c b/drivers/crypto/inside-secure/safexcel.c
> index 9ca80d082c4fb..c3b2b22934b7e 100644
> --- a/drivers/crypto/inside-secure/safexcel.c
> +++ b/drivers/crypto/inside-secure/safexcel.c
> @@ -1216,11 +1216,10 @@ static struct safexcel_alg_template *safexcel_algs[] = {
> &safexcel_alg_authenc_hmac_sha384_ctr_aes,
> &safexcel_alg_authenc_hmac_sha512_ctr_aes,
> &safexcel_alg_xts_aes,
> &safexcel_alg_gcm,
> &safexcel_alg_ccm,
> - &safexcel_alg_crc32,
> &safexcel_alg_cbcmac,
> &safexcel_alg_xcbcmac,
> &safexcel_alg_cmac,
> &safexcel_alg_chacha20,
> &safexcel_alg_chachapoly,
> diff --git a/drivers/crypto/inside-secure/safexcel.h b/drivers/crypto/inside-secure/safexcel.h
> index 0c79ad78d1c0a..0f27367a85fa2 100644
> --- a/drivers/crypto/inside-secure/safexcel.h
> +++ b/drivers/crypto/inside-secure/safexcel.h
> @@ -957,11 +957,10 @@ extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha256_ctr_aes;
> extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha384_ctr_aes;
> extern struct safexcel_alg_template safexcel_alg_authenc_hmac_sha512_ctr_aes;
> extern struct safexcel_alg_template safexcel_alg_xts_aes;
> extern struct safexcel_alg_template safexcel_alg_gcm;
> extern struct safexcel_alg_template safexcel_alg_ccm;
> -extern struct safexcel_alg_template safexcel_alg_crc32;
> extern struct safexcel_alg_template safexcel_alg_cbcmac;
> extern struct safexcel_alg_template safexcel_alg_xcbcmac;
> extern struct safexcel_alg_template safexcel_alg_cmac;
> extern struct safexcel_alg_template safexcel_alg_chacha20;
> extern struct safexcel_alg_template safexcel_alg_chachapoly;
> diff --git a/drivers/crypto/inside-secure/safexcel_hash.c b/drivers/crypto/inside-secure/safexcel_hash.c
> index d2b632193bebb..fd34dc8f5707d 100644
> --- a/drivers/crypto/inside-secure/safexcel_hash.c
> +++ b/drivers/crypto/inside-secure/safexcel_hash.c
> @@ -287,18 +287,12 @@ static int safexcel_handle_req_result(struct safexcel_crypto_priv *priv,
>
> *should_complete = false; /* Not done yet */
> return 1;
> }
>
> - if (unlikely(sreq->digest == CONTEXT_CONTROL_DIGEST_XCM &&
> - ctx->alg == CONTEXT_CONTROL_CRYPTO_ALG_CRC32)) {
> - /* Undo final XOR with 0xffffffff ...*/
> - *(__le32 *)areq->result = ~sreq->state[0];
> - } else {
> - memcpy(areq->result, sreq->state,
> - crypto_ahash_digestsize(ahash));
> - }
> + memcpy(areq->result, sreq->state,
> + crypto_ahash_digestsize(ahash));
> }
>
> cache_len = safexcel_queued_len(sreq);
> if (cache_len)
> memcpy(sreq->cache, sreq->cache_next, cache_len);
> @@ -1879,92 +1873,10 @@ struct safexcel_alg_template safexcel_alg_hmac_md5 = {
> },
> },
> },
> };
>
> -static int safexcel_crc32_cra_init(struct crypto_tfm *tfm)
> -{
> - struct safexcel_ahash_ctx *ctx = crypto_tfm_ctx(tfm);
> - int ret = safexcel_ahash_cra_init(tfm);
> -
> - /* Default 'key' is all zeroes */
> - memset(&ctx->base.ipad, 0, sizeof(u32));
> - return ret;
> -}
> -
> -static int safexcel_crc32_init(struct ahash_request *areq)
> -{
> - struct safexcel_ahash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(areq));
> - struct safexcel_ahash_req *req = ahash_request_ctx_dma(areq);
> -
> - memset(req, 0, sizeof(*req));
> -
> - /* Start from loaded key */
> - req->state[0] = cpu_to_le32(~ctx->base.ipad.word[0]);
> - /* Set processed to non-zero to enable invalidation detection */
> - req->len = sizeof(u32);
> - req->processed = sizeof(u32);
> -
> - ctx->alg = CONTEXT_CONTROL_CRYPTO_ALG_CRC32;
> - req->digest = CONTEXT_CONTROL_DIGEST_XCM;
> - req->state_sz = sizeof(u32);
> - req->digest_sz = sizeof(u32);
> - req->block_sz = sizeof(u32);
> -
> - return 0;
> -}
> -
> -static int safexcel_crc32_setkey(struct crypto_ahash *tfm, const u8 *key,
> - unsigned int keylen)
> -{
> - struct safexcel_ahash_ctx *ctx = crypto_tfm_ctx(crypto_ahash_tfm(tfm));
> -
> - if (keylen != sizeof(u32))
> - return -EINVAL;
> -
> - memcpy(&ctx->base.ipad, key, sizeof(u32));
> - return 0;
> -}
> -
> -static int safexcel_crc32_digest(struct ahash_request *areq)
> -{
> - return safexcel_crc32_init(areq) ?: safexcel_ahash_finup(areq);
> -}
> -
> -struct safexcel_alg_template safexcel_alg_crc32 = {
> - .type = SAFEXCEL_ALG_TYPE_AHASH,
> - .algo_mask = 0,
> - .alg.ahash = {
> - .init = safexcel_crc32_init,
> - .update = safexcel_ahash_update,
> - .final = safexcel_ahash_final,
> - .finup = safexcel_ahash_finup,
> - .digest = safexcel_crc32_digest,
> - .setkey = safexcel_crc32_setkey,
> - .export = safexcel_ahash_export,
> - .import = safexcel_ahash_import,
> - .halg = {
> - .digestsize = sizeof(u32),
> - .statesize = sizeof(struct safexcel_ahash_export_state),
> - .base = {
> - .cra_name = "crc32",
> - .cra_driver_name = "safexcel-crc32",
> - .cra_priority = SAFEXCEL_CRA_PRIORITY,
> - .cra_flags = CRYPTO_ALG_OPTIONAL_KEY |
> - CRYPTO_ALG_ASYNC |
> - CRYPTO_ALG_ALLOCATES_MEMORY |
> - CRYPTO_ALG_KERN_DRIVER_ONLY,
> - .cra_blocksize = 1,
> - .cra_ctxsize = sizeof(struct safexcel_ahash_ctx),
> - .cra_init = safexcel_crc32_cra_init,
> - .cra_exit = safexcel_ahash_cra_exit,
> - .cra_module = THIS_MODULE,
> - },
> - },
> - },
> -};
> -
> static int safexcel_cbcmac_init(struct ahash_request *areq)
> {
> struct safexcel_ahash_ctx *ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(areq));
> struct safexcel_ahash_req *req = ahash_request_ctx_dma(areq);
>
>
> base-commit: 4cb6c8af8591135ec000fbe4bb474139ceec595d
> --
> 2.49.0
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] crypto: inside-secure - remove crc32 support
2025-05-31 20:42 [PATCH] crypto: inside-secure - remove crc32 support Eric Biggers
2025-06-01 9:03 ` Ard Biesheuvel
@ 2025-06-08 23:41 ` Eric Biggers
1 sibling, 0 replies; 3+ messages in thread
From: Eric Biggers @ 2025-06-08 23:41 UTC (permalink / raw)
To: linux-kernel; +Cc: linux-crypto, Ard Biesheuvel, Antoine Tenart
On Sat, May 31, 2025 at 01:42:44PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@google.com>
>
> The crc32 acceleration in the inside-secure driver is accessible only as
> an asynchronous hash. However, there seems to be no corresponding user
> of crc32 in the kernel that supports asynchronous hashes. Therefore,
> this code seems to be unused.
>
> The patch that added this code provided no justification for its
> inclusion. All devicetree bindings for this accelerator are for arm64;
> arm64 CPUs often have CRC or PMULL instructions, which already
> accelerate crc32 very well. And these actually work with the crc32
> users in the kernel, unlike this driver which doesn't.
>
> Remove this unnecessary code.
>
> Cc: Antoine Tenart <atenart@kernel.org>
> Signed-off-by: Eric Biggers <ebiggers@google.com>
> ---
>
> I'm planning to take this patch via the crc tree.
>
> drivers/crypto/inside-secure/safexcel.c | 1 -
> drivers/crypto/inside-secure/safexcel.h | 1 -
> drivers/crypto/inside-secure/safexcel_hash.c | 92 +-------------------
> 3 files changed, 2 insertions(+), 92 deletions(-)
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/ebiggers/linux.git/log/?h=crc-next
- Eric
^ permalink raw reply [flat|nested] 3+ messages in thread
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