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crypto: {arm,arm64,mips}/poly1305 - remove redundant non-reduction from emit

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This appears to be some kind of copy and paste error, and is actually
dead code.

Pre: f = 0 ⇒ (f >> 32) = 0
    f = (f >> 32) + le32_to_cpu(digest[0]);
Post: 0 ≤ f < 2³²
    put_unaligned_le32(f, dst);

Pre: 0 ≤ f < 2³² ⇒ (f >> 32) = 0
    f = (f >> 32) + le32_to_cpu(digest[1]);
Post: 0 ≤ f < 2³²
    put_unaligned_le32(f, dst + 4);

Pre: 0 ≤ f < 2³² ⇒ (f >> 32) = 0
    f = (f >> 32) + le32_to_cpu(digest[2]);
Post: 0 ≤ f < 2³²
    put_unaligned_le32(f, dst + 8);

Pre: 0 ≤ f < 2³² ⇒ (f >> 32) = 0
    f = (f >> 32) + le32_to_cpu(digest[3]);
Post: 0 ≤ f < 2³²
    put_unaligned_le32(f, dst + 12);

Therefore this sequence is redundant. And Andy's code appears to handle
misalignment acceptably.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Tested-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Jason A. Donenfeld 2020-01-05 22:40:49 -05:00 committed by Herbert Xu
parent d7d7b85356
commit 31899908a0
3 changed files with 6 additions and 48 deletions
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18
arch/arm/crypto/poly1305-glue.c
View File

@ -20,7 +20,7 @@
void poly1305_init_arm(void *state, const u8 *key);
void poly1305_blocks_arm(void *state, const u8 *src, u32 len, u32 hibit);
void poly1305_emit_arm(void *state, __le32 *digest, const u32 *nonce);
void poly1305_emit_arm(void *state, u8 *digest, const u32 *nonce);
void __weak poly1305_blocks_neon(void *state, const u8 *src, u32 len, u32 hibit)
{
@ -179,9 +179,6 @@ EXPORT_SYMBOL(poly1305_update_arch);
void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
{
__le32 digest[4];
u64 f = 0;
if (unlikely(dctx->buflen)) {
dctx->buf[dctx->buflen++] = 1;
memset(dctx->buf + dctx->buflen, 0,
@ -189,18 +186,7 @@ void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
poly1305_blocks_arm(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0);
}
poly1305_emit_arm(&dctx->h, digest, dctx->s);
/* mac = (h + s) % (2^128) */
f = (f >> 32) + le32_to_cpu(digest[0]);
put_unaligned_le32(f, dst);
f = (f >> 32) + le32_to_cpu(digest[1]);
put_unaligned_le32(f, dst + 4);
f = (f >> 32) + le32_to_cpu(digest[2]);
put_unaligned_le32(f, dst + 8);
f = (f >> 32) + le32_to_cpu(digest[3]);
put_unaligned_le32(f, dst + 12);
poly1305_emit_arm(&dctx->h, dst, dctx->s);
*dctx = (struct poly1305_desc_ctx){};
}
EXPORT_SYMBOL(poly1305_final_arch);

18
arch/arm64/crypto/poly1305-glue.c
View File

@ -21,7 +21,7 @@
asmlinkage void poly1305_init_arm64(void *state, const u8 *key);
asmlinkage void poly1305_blocks(void *state, const u8 *src, u32 len, u32 hibit);
asmlinkage void poly1305_blocks_neon(void *state, const u8 *src, u32 len, u32 hibit);
asmlinkage void poly1305_emit(void *state, __le32 *digest, const u32 *nonce);
asmlinkage void poly1305_emit(void *state, u8 *digest, const u32 *nonce);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
@ -162,9 +162,6 @@ EXPORT_SYMBOL(poly1305_update_arch);
void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
{
__le32 digest[4];
u64 f = 0;
if (unlikely(dctx->buflen)) {
dctx->buf[dctx->buflen++] = 1;
memset(dctx->buf + dctx->buflen, 0,
@ -172,18 +169,7 @@ void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
poly1305_blocks(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0);
}
poly1305_emit(&dctx->h, digest, dctx->s);
/* mac = (h + s) % (2^128) */
f = (f >> 32) + le32_to_cpu(digest[0]);
put_unaligned_le32(f, dst);
f = (f >> 32) + le32_to_cpu(digest[1]);
put_unaligned_le32(f, dst + 4);
f = (f >> 32) + le32_to_cpu(digest[2]);
put_unaligned_le32(f, dst + 8);
f = (f >> 32) + le32_to_cpu(digest[3]);
put_unaligned_le32(f, dst + 12);
poly1305_emit(&dctx->h, dst, dctx->s);
*dctx = (struct poly1305_desc_ctx){};
}
EXPORT_SYMBOL(poly1305_final_arch);

18
arch/mips/crypto/poly1305-glue.c
View File

@ -15,7 +15,7 @@
asmlinkage void poly1305_init_mips(void *state, const u8 *key);
asmlinkage void poly1305_blocks_mips(void *state, const u8 *src, u32 len, u32 hibit);
asmlinkage void poly1305_emit_mips(void *state, __le32 *digest, const u32 *nonce);
asmlinkage void poly1305_emit_mips(void *state, u8 *digest, const u32 *nonce);
void poly1305_init_arch(struct poly1305_desc_ctx *dctx, const u8 *key)
{
@ -134,9 +134,6 @@ EXPORT_SYMBOL(poly1305_update_arch);
void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
{
__le32 digest[4];
u64 f = 0;
if (unlikely(dctx->buflen)) {
dctx->buf[dctx->buflen++] = 1;
memset(dctx->buf + dctx->buflen, 0,
@ -144,18 +141,7 @@ void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
poly1305_blocks_mips(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0);
}
poly1305_emit_mips(&dctx->h, digest, dctx->s);
/* mac = (h + s) % (2^128) */
f = (f >> 32) + le32_to_cpu(digest[0]);
put_unaligned_le32(f, dst);
f = (f >> 32) + le32_to_cpu(digest[1]);
put_unaligned_le32(f, dst + 4);
f = (f >> 32) + le32_to_cpu(digest[2]);
put_unaligned_le32(f, dst + 8);
f = (f >> 32) + le32_to_cpu(digest[3]);
put_unaligned_le32(f, dst + 12);
poly1305_emit_mips(&dctx->h, dst, dctx->s);
*dctx = (struct poly1305_desc_ctx){};
}
EXPORT_SYMBOL(poly1305_final_arch);