AES in CTR mode is used by modes such as GCM and CCM, which are often
used in contexts where only synchronous ciphers are permitted. So
provide a synchronous version of ctr(aes) based on the existing code.
This requires a non-SIMD fallback to deal with invocations occurring
from a context where SIMD instructions may not be used. We have a
helper for this now in the AES library, so wire that up.

Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
---
 arch/arm/crypto/aes-ce-glue.c | 36 ++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/arch/arm/crypto/aes-ce-glue.c b/arch/arm/crypto/aes-ce-glue.c
index 04ba66903674..cdcc4b09e7db 100644
--- a/arch/arm/crypto/aes-ce-glue.c
+++ b/arch/arm/crypto/aes-ce-glue.c
@@ -10,6 +10,7 @@
 
 #include <asm/hwcap.h>
 #include <asm/neon.h>
+#include <asm/simd.h>
 #include <crypto/aes.h>
 #include <crypto/internal/simd.h>
 #include <crypto/internal/skcipher.h>
@@ -292,6 +293,23 @@ static int ctr_encrypt(struct skcipher_request *req)
        return err;
 }
 
+static int ctr_encrypt_sync(struct skcipher_request *req)
+{
+       struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
+       struct crypto_aes_ctx *ctx = crypto_skcipher_ctx(tfm);
+
+       if (!crypto_simd_usable()) {
+               struct skcipher_walk walk;
+               int err;
+
+               err = skcipher_walk_virt(&walk, req, true);
+               if (err)
+                       return err;
+               return skcipher_encrypt_aes_ctr(&walk, ctx);
+       }
+       return ctr_encrypt(req);
+}
+
 static int xts_encrypt(struct skcipher_request *req)
 {
        struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
@@ -381,6 +399,21 @@ static struct skcipher_alg aes_algs[] = { {
        .setkey                 = ce_aes_setkey,
        .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",
@@ -424,6 +457,9 @@ static int __init aes_init(void)
                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;
-- 
2.20.1

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