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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2018-03-10 15:21:47 +0000
committerHerbert Xu <herbert@gondor.apana.org.au>2018-03-16 23:35:54 +0800
commitbd2ad885e30d2c72996e051d9a81bd1f2694eba0 (patch)
treebc1b5fa3e6b67b7ded21eba6c14786d8da2391a7
parent702202f1d421af535b3074930344276f5361dd0e (diff)
crypto: arm64/aes-ce-ccm - move kernel mode neon en/disable into loop
When kernel mode NEON was first introduced on arm64, the preserve and restore of the userland NEON state was completely unoptimized, and involved saving all registers on each call to kernel_neon_begin(), and restoring them on each call to kernel_neon_end(). For this reason, the NEON crypto code that was introduced at the time keeps the NEON enabled throughout the execution of the crypto API methods, which may include calls back into the crypto API that could result in memory allocation or other actions that we should avoid when running with preemption disabled. Since then, we have optimized the kernel mode NEON handling, which now restores lazily (upon return to userland), and so the preserve action is only costly the first time it is called after entering the kernel. So let's put the kernel_neon_begin() and kernel_neon_end() calls around the actual invocations of the NEON crypto code, and run the remainder of the code with kernel mode NEON disabled (and preemption enabled) Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--arch/arm64/crypto/aes-ce-ccm-glue.c47
1 files changed, 23 insertions, 24 deletions
diff --git a/arch/arm64/crypto/aes-ce-ccm-glue.c b/arch/arm64/crypto/aes-ce-ccm-glue.c
index a1254036f2b1..68b11aa690e4 100644
--- a/arch/arm64/crypto/aes-ce-ccm-glue.c
+++ b/arch/arm64/crypto/aes-ce-ccm-glue.c
@@ -107,11 +107,13 @@ static int ccm_init_mac(struct aead_request *req, u8 maciv[], u32 msglen)
}
static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
- u32 abytes, u32 *macp, bool use_neon)
+ u32 abytes, u32 *macp)
{
- if (likely(use_neon)) {
+ if (may_use_simd()) {
+ kernel_neon_begin();
ce_aes_ccm_auth_data(mac, in, abytes, macp, key->key_enc,
num_rounds(key));
+ kernel_neon_end();
} else {
if (*macp > 0 && *macp < AES_BLOCK_SIZE) {
int added = min(abytes, AES_BLOCK_SIZE - *macp);
@@ -143,8 +145,7 @@ static void ccm_update_mac(struct crypto_aes_ctx *key, u8 mac[], u8 const in[],
}
}
-static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[],
- bool use_neon)
+static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[])
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_aes_ctx *ctx = crypto_aead_ctx(aead);
@@ -163,7 +164,7 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[],
ltag.len = 6;
}
- ccm_update_mac(ctx, mac, (u8 *)&ltag, ltag.len, &macp, use_neon);
+ ccm_update_mac(ctx, mac, (u8 *)&ltag, ltag.len, &macp);
scatterwalk_start(&walk, req->src);
do {
@@ -175,7 +176,7 @@ static void ccm_calculate_auth_mac(struct aead_request *req, u8 mac[],
n = scatterwalk_clamp(&walk, len);
}
p = scatterwalk_map(&walk);
- ccm_update_mac(ctx, mac, p, n, &macp, use_neon);
+ ccm_update_mac(ctx, mac, p, n, &macp);
len -= n;
scatterwalk_unmap(p);
@@ -242,43 +243,42 @@ static int ccm_encrypt(struct aead_request *req)
u8 __aligned(8) mac[AES_BLOCK_SIZE];
u8 buf[AES_BLOCK_SIZE];
u32 len = req->cryptlen;
- bool use_neon = may_use_simd();
int err;
err = ccm_init_mac(req, mac, len);
if (err)
return err;
- if (likely(use_neon))
- kernel_neon_begin();
-
if (req->assoclen)
- ccm_calculate_auth_mac(req, mac, use_neon);
+ ccm_calculate_auth_mac(req, mac);
/* preserve the original iv for the final round */
memcpy(buf, req->iv, AES_BLOCK_SIZE);
err = skcipher_walk_aead_encrypt(&walk, req, true);
- if (likely(use_neon)) {
+ if (may_use_simd()) {
while (walk.nbytes) {
u32 tail = walk.nbytes % AES_BLOCK_SIZE;
if (walk.nbytes == walk.total)
tail = 0;
+ kernel_neon_begin();
ce_aes_ccm_encrypt(walk.dst.virt.addr,
walk.src.virt.addr,
walk.nbytes - tail, ctx->key_enc,
num_rounds(ctx), mac, walk.iv);
+ kernel_neon_end();
err = skcipher_walk_done(&walk, tail);
}
- if (!err)
+ if (!err) {
+ kernel_neon_begin();
ce_aes_ccm_final(mac, buf, ctx->key_enc,
num_rounds(ctx));
-
- kernel_neon_end();
+ kernel_neon_end();
+ }
} else {
err = ccm_crypt_fallback(&walk, mac, buf, ctx, true);
}
@@ -301,43 +301,42 @@ static int ccm_decrypt(struct aead_request *req)
u8 __aligned(8) mac[AES_BLOCK_SIZE];
u8 buf[AES_BLOCK_SIZE];
u32 len = req->cryptlen - authsize;
- bool use_neon = may_use_simd();
int err;
err = ccm_init_mac(req, mac, len);
if (err)
return err;
- if (likely(use_neon))
- kernel_neon_begin();
-
if (req->assoclen)
- ccm_calculate_auth_mac(req, mac, use_neon);
+ ccm_calculate_auth_mac(req, mac);
/* preserve the original iv for the final round */
memcpy(buf, req->iv, AES_BLOCK_SIZE);
err = skcipher_walk_aead_decrypt(&walk, req, true);
- if (likely(use_neon)) {
+ if (may_use_simd()) {
while (walk.nbytes) {
u32 tail = walk.nbytes % AES_BLOCK_SIZE;
if (walk.nbytes == walk.total)
tail = 0;
+ kernel_neon_begin();
ce_aes_ccm_decrypt(walk.dst.virt.addr,
walk.src.virt.addr,
walk.nbytes - tail, ctx->key_enc,
num_rounds(ctx), mac, walk.iv);
+ kernel_neon_end();
err = skcipher_walk_done(&walk, tail);
}
- if (!err)
+ if (!err) {
+ kernel_neon_begin();
ce_aes_ccm_final(mac, buf, ctx->key_enc,
num_rounds(ctx));
-
- kernel_neon_end();
+ kernel_neon_end();
+ }
} else {
err = ccm_crypt_fallback(&walk, mac, buf, ctx, false);
}