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31899908a0
linux/arch/arm/crypto/poly1305-glue.c
Jason A. Donenfeld 31899908a0 crypto: {arm,arm64,mips}/poly1305 - remove redundant non-reduction from emit 
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>
2020-01-16 15:18:12 +08:00

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// SPDX-License-Identifier: GPL-2.0
/*
* OpenSSL/Cryptogams accelerated Poly1305 transform for ARM
*
* Copyright (C) 2019 Linaro Ltd. <ard.biesheuvel@linaro.org>
*/
#include <asm/hwcap.h>
#include <asm/neon.h>
#include <asm/simd.h>
#include <asm/unaligned.h>
#include <crypto/algapi.h>
#include <crypto/internal/hash.h>
#include <crypto/internal/poly1305.h>
#include <crypto/internal/simd.h>
#include <linux/cpufeature.h>
#include <linux/crypto.h>
#include <linux/jump_label.h>
#include <linux/module.h>
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, u8 *digest, const u32 *nonce);
void __weak poly1305_blocks_neon(void *state, const u8 *src, u32 len, u32 hibit)
{
}
static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_neon);
void poly1305_init_arch(struct poly1305_desc_ctx *dctx, const u8 *key)
{
poly1305_init_arm(&dctx->h, key);
dctx->s[0] = get_unaligned_le32(key + 16);
dctx->s[1] = get_unaligned_le32(key + 20);
dctx->s[2] = get_unaligned_le32(key + 24);
dctx->s[3] = get_unaligned_le32(key + 28);
dctx->buflen = 0;
}
EXPORT_SYMBOL(poly1305_init_arch);
static int arm_poly1305_init(struct shash_desc *desc)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
dctx->buflen = 0;
dctx->rset = 0;
dctx->sset = false;
return 0;
}
static void arm_poly1305_blocks(struct poly1305_desc_ctx *dctx, const u8 *src,
u32 len, u32 hibit, bool do_neon)
{
if (unlikely(!dctx->sset)) {
if (!dctx->rset) {
poly1305_init_arm(&dctx->h, src);
src += POLY1305_BLOCK_SIZE;
len -= POLY1305_BLOCK_SIZE;
dctx->rset = 1;
}
if (len >= POLY1305_BLOCK_SIZE) {
dctx->s[0] = get_unaligned_le32(src + 0);
dctx->s[1] = get_unaligned_le32(src + 4);
dctx->s[2] = get_unaligned_le32(src + 8);
dctx->s[3] = get_unaligned_le32(src + 12);
src += POLY1305_BLOCK_SIZE;
len -= POLY1305_BLOCK_SIZE;
dctx->sset = true;
}
if (len < POLY1305_BLOCK_SIZE)
return;
}
len &= ~(POLY1305_BLOCK_SIZE - 1);
if (static_branch_likely(&have_neon) && likely(do_neon))
poly1305_blocks_neon(&dctx->h, src, len, hibit);
else
poly1305_blocks_arm(&dctx->h, src, len, hibit);
}
static void arm_poly1305_do_update(struct poly1305_desc_ctx *dctx,
const u8 *src, u32 len, bool do_neon)
{
if (unlikely(dctx->buflen)) {
u32 bytes = min(len, POLY1305_BLOCK_SIZE - dctx->buflen);
memcpy(dctx->buf + dctx->buflen, src, bytes);
src += bytes;
len -= bytes;
dctx->buflen += bytes;
if (dctx->buflen == POLY1305_BLOCK_SIZE) {
arm_poly1305_blocks(dctx, dctx->buf,
POLY1305_BLOCK_SIZE, 1, false);
dctx->buflen = 0;
}
}
if (likely(len >= POLY1305_BLOCK_SIZE)) {
arm_poly1305_blocks(dctx, src, len, 1, do_neon);
src += round_down(len, POLY1305_BLOCK_SIZE);
len %= POLY1305_BLOCK_SIZE;
}
if (unlikely(len)) {
dctx->buflen = len;
memcpy(dctx->buf, src, len);
}
}
static int arm_poly1305_update(struct shash_desc *desc,
const u8 *src, unsigned int srclen)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
arm_poly1305_do_update(dctx, src, srclen, false);
return 0;
}
static int __maybe_unused arm_poly1305_update_neon(struct shash_desc *desc,
const u8 *src,
unsigned int srclen)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
bool do_neon = crypto_simd_usable() && srclen > 128;
if (static_branch_likely(&have_neon) && do_neon)
kernel_neon_begin();
arm_poly1305_do_update(dctx, src, srclen, do_neon);
if (static_branch_likely(&have_neon) && do_neon)
kernel_neon_end();
return 0;
}
void poly1305_update_arch(struct poly1305_desc_ctx *dctx, const u8 *src,
unsigned int nbytes)
{
bool do_neon = IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
crypto_simd_usable();
if (unlikely(dctx->buflen)) {
u32 bytes = min(nbytes, POLY1305_BLOCK_SIZE - dctx->buflen);
memcpy(dctx->buf + dctx->buflen, src, bytes);
src += bytes;
nbytes -= bytes;
dctx->buflen += bytes;
if (dctx->buflen == POLY1305_BLOCK_SIZE) {
poly1305_blocks_arm(&dctx->h, dctx->buf,
POLY1305_BLOCK_SIZE, 1);
dctx->buflen = 0;
}
}
if (likely(nbytes >= POLY1305_BLOCK_SIZE)) {
unsigned int len = round_down(nbytes, POLY1305_BLOCK_SIZE);
if (static_branch_likely(&have_neon) && do_neon) {
kernel_neon_begin();
poly1305_blocks_neon(&dctx->h, src, len, 1);
kernel_neon_end();
} else {
poly1305_blocks_arm(&dctx->h, src, len, 1);
}
src += len;
nbytes %= POLY1305_BLOCK_SIZE;
}
if (unlikely(nbytes)) {
dctx->buflen = nbytes;
memcpy(dctx->buf, src, nbytes);
}
}
EXPORT_SYMBOL(poly1305_update_arch);
void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst)
{
if (unlikely(dctx->buflen)) {
dctx->buf[dctx->buflen++] = 1;
memset(dctx->buf + dctx->buflen, 0,
POLY1305_BLOCK_SIZE - dctx->buflen);
poly1305_blocks_arm(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0);
}
poly1305_emit_arm(&dctx->h, dst, dctx->s);
*dctx = (struct poly1305_desc_ctx){};
}
EXPORT_SYMBOL(poly1305_final_arch);
static int arm_poly1305_final(struct shash_desc *desc, u8 *dst)
{
struct poly1305_desc_ctx *dctx = shash_desc_ctx(desc);
if (unlikely(!dctx->sset))
return -ENOKEY;
poly1305_final_arch(dctx, dst);
return 0;
}
static struct shash_alg arm_poly1305_algs[] = {{
.init = arm_poly1305_init,
.update = arm_poly1305_update,
.final = arm_poly1305_final,
.digestsize = POLY1305_DIGEST_SIZE,
.descsize = sizeof(struct poly1305_desc_ctx),
.base.cra_name = "poly1305",
.base.cra_driver_name = "poly1305-arm",
.base.cra_priority = 150,
.base.cra_blocksize = POLY1305_BLOCK_SIZE,
.base.cra_module = THIS_MODULE,
#ifdef CONFIG_KERNEL_MODE_NEON
}, {
.init = arm_poly1305_init,
.update = arm_poly1305_update_neon,
.final = arm_poly1305_final,
.digestsize = POLY1305_DIGEST_SIZE,
.descsize = sizeof(struct poly1305_desc_ctx),
.base.cra_name = "poly1305",
.base.cra_driver_name = "poly1305-neon",
.base.cra_priority = 200,
.base.cra_blocksize = POLY1305_BLOCK_SIZE,
.base.cra_module = THIS_MODULE,
#endif
}};
static int __init arm_poly1305_mod_init(void)
{
if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) &&
(elf_hwcap & HWCAP_NEON))
static_branch_enable(&have_neon);
else if (IS_REACHABLE(CONFIG_CRYPTO_HASH))
/* register only the first entry */
return crypto_register_shash(&arm_poly1305_algs[0]);
return IS_REACHABLE(CONFIG_CRYPTO_HASH) ?
crypto_register_shashes(arm_poly1305_algs,
ARRAY_SIZE(arm_poly1305_algs)) : 0;
}
static void __exit arm_poly1305_mod_exit(void)
{
if (!IS_REACHABLE(CONFIG_CRYPTO_HASH))
return;
if (!static_branch_likely(&have_neon)) {
crypto_unregister_shash(&arm_poly1305_algs[0]);
return;
}
crypto_unregister_shashes(arm_poly1305_algs,
ARRAY_SIZE(arm_poly1305_algs));
}
module_init(arm_poly1305_mod_init);
module_exit(arm_poly1305_mod_exit);
MODULE_LICENSE("GPL v2");
MODULE_ALIAS_CRYPTO("poly1305");
MODULE_ALIAS_CRYPTO("poly1305-arm");
MODULE_ALIAS_CRYPTO("poly1305-neon");
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