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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* x64 SIMD accelerated ChaCha and XChaCha stream ciphers,
* including ChaCha20 (RFC7539)
*
* Copyright (C) 2015 Martin Willi
*/
#include <crypto/algapi.h>
#include <crypto/chacha.h>
#include <crypto/internal/simd.h>
#include <crypto/internal/skcipher.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/simd.h>
#define CHACHA_STATE_ALIGN 16
asmlinkage void chacha_block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds);
asmlinkage void chacha_4block_xor_ssse3(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds);
asmlinkage void hchacha_block_ssse3(const u32 *state, u32 *out, int nrounds);
#ifdef CONFIG_AS_AVX2
asmlinkage void chacha_2block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds);
asmlinkage void chacha_4block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds);
asmlinkage void chacha_8block_xor_avx2(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds);
static bool chacha_use_avx2;
#ifdef CONFIG_AS_AVX512
asmlinkage void chacha_2block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds);
asmlinkage void chacha_4block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds);
asmlinkage void chacha_8block_xor_avx512vl(u32 *state, u8 *dst, const u8 *src,
unsigned int len, int nrounds);
static bool chacha_use_avx512vl;
#endif
#endif
static unsigned int chacha_advance(unsigned int len, unsigned int maxblocks)
{
len = min(len, maxblocks * CHACHA_BLOCK_SIZE);
return round_up(len, CHACHA_BLOCK_SIZE) / CHACHA_BLOCK_SIZE;
}
static void chacha_dosimd(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes, int nrounds)
{
#ifdef CONFIG_AS_AVX2
#ifdef CONFIG_AS_AVX512
if (chacha_use_avx512vl) {
while (bytes >= CHACHA_BLOCK_SIZE * 8) {
chacha_8block_xor_avx512vl(state, dst, src, bytes,
nrounds);
bytes -= CHACHA_BLOCK_SIZE * 8;
src += CHACHA_BLOCK_SIZE * 8;
dst += CHACHA_BLOCK_SIZE * 8;
state[12] += 8;
}
if (bytes > CHACHA_BLOCK_SIZE * 4) {
chacha_8block_xor_avx512vl(state, dst, src, bytes,
nrounds);
state[12] += chacha_advance(bytes, 8);
return;
}
if (bytes > CHACHA_BLOCK_SIZE * 2) {
chacha_4block_xor_avx512vl(state, dst, src, bytes,
nrounds);
state[12] += chacha_advance(bytes, 4);
return;
}
if (bytes) {
chacha_2block_xor_avx512vl(state, dst, src, bytes,
nrounds);
state[12] += chacha_advance(bytes, 2);
return;
}
}
#endif
if (chacha_use_avx2) {
while (bytes >= CHACHA_BLOCK_SIZE * 8) {
chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
bytes -= CHACHA_BLOCK_SIZE * 8;
src += CHACHA_BLOCK_SIZE * 8;
dst += CHACHA_BLOCK_SIZE * 8;
state[12] += 8;
}
if (bytes > CHACHA_BLOCK_SIZE * 4) {
chacha_8block_xor_avx2(state, dst, src, bytes, nrounds);
state[12] += chacha_advance(bytes, 8);
return;
}
if (bytes > CHACHA_BLOCK_SIZE * 2) {
chacha_4block_xor_avx2(state, dst, src, bytes, nrounds);
state[12] += chacha_advance(bytes, 4);
return;
}
if (bytes > CHACHA_BLOCK_SIZE) {
chacha_2block_xor_avx2(state, dst, src, bytes, nrounds);
state[12] += chacha_advance(bytes, 2);
return;
}
}
#endif
while (bytes >= CHACHA_BLOCK_SIZE * 4) {
chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
bytes -= CHACHA_BLOCK_SIZE * 4;
src += CHACHA_BLOCK_SIZE * 4;
dst += CHACHA_BLOCK_SIZE * 4;
state[12] += 4;
}
if (bytes > CHACHA_BLOCK_SIZE) {
chacha_4block_xor_ssse3(state, dst, src, bytes, nrounds);
state[12] += chacha_advance(bytes, 4);
return;
}
if (bytes) {
chacha_block_xor_ssse3(state, dst, src, bytes, nrounds);
state[12]++;
}
}
static int chacha_simd_stream_xor(struct skcipher_walk *walk,
const struct chacha_ctx *ctx, const u8 *iv)
{
u32 *state, state_buf[16 + 2] __aligned(8);
int next_yield = 4096; /* bytes until next FPU yield */
int err = 0;
BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
crypto_chacha_init(state, ctx, iv);
while (walk->nbytes > 0) {
unsigned int nbytes = walk->nbytes;
if (nbytes < walk->total) {
nbytes = round_down(nbytes, walk->stride);
next_yield -= nbytes;
}
chacha_dosimd(state, walk->dst.virt.addr, walk->src.virt.addr,
nbytes, ctx->nrounds);
if (next_yield <= 0) {
/* temporarily allow preemption */
kernel_fpu_end();
kernel_fpu_begin();
next_yield = 4096;
}
err = skcipher_walk_done(walk, walk->nbytes - nbytes);
}
return err;
}
static int chacha_simd(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
int err;
if (req->cryptlen <= CHACHA_BLOCK_SIZE || !crypto_simd_usable())
return crypto_chacha_crypt(req);
err = skcipher_walk_virt(&walk, req, true);
if (err)
return err;
kernel_fpu_begin();
err = chacha_simd_stream_xor(&walk, ctx, req->iv);
kernel_fpu_end();
return err;
}
static int xchacha_simd(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
struct chacha_ctx subctx;
u32 *state, state_buf[16 + 2] __aligned(8);
u8 real_iv[16];
int err;
if (req->cryptlen <= CHACHA_BLOCK_SIZE || !crypto_simd_usable())
return crypto_xchacha_crypt(req);
err = skcipher_walk_virt(&walk, req, true);
if (err)
return err;
BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
state = PTR_ALIGN(state_buf + 0, CHACHA_STATE_ALIGN);
crypto_chacha_init(state, ctx, req->iv);
kernel_fpu_begin();
hchacha_block_ssse3(state, subctx.key, ctx->nrounds);
subctx.nrounds = ctx->nrounds;
memcpy(&real_iv[0], req->iv + 24, 8);
memcpy(&real_iv[8], req->iv + 16, 8);
err = chacha_simd_stream_xor(&walk, &subctx, real_iv);
kernel_fpu_end();
return err;
}
static struct skcipher_alg algs[] = {
{
.base.cra_name = "chacha20",
.base.cra_driver_name = "chacha20-simd",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = CHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.setkey = crypto_chacha20_setkey,
.encrypt = chacha_simd,
.decrypt = chacha_simd,
}, {
.base.cra_name = "xchacha20",
.base.cra_driver_name = "xchacha20-simd",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = XCHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.setkey = crypto_chacha20_setkey,
.encrypt = xchacha_simd,
.decrypt = xchacha_simd,
}, {
.base.cra_name = "xchacha12",
.base.cra_driver_name = "xchacha12-simd",
.base.cra_priority = 300,
.base.cra_blocksize = 1,
.base.cra_ctxsize = sizeof(struct chacha_ctx),
.base.cra_module = THIS_MODULE,
.min_keysize = CHACHA_KEY_SIZE,
.max_keysize = CHACHA_KEY_SIZE,
.ivsize = XCHACHA_IV_SIZE,
.chunksize = CHACHA_BLOCK_SIZE,
.setkey = crypto_chacha12_setkey,
.encrypt = xchacha_simd,
.decrypt = xchacha_simd,
},
};
static int __init chacha_simd_mod_init(void)
{
if (!boot_cpu_has(X86_FEATURE_SSSE3))
return -ENODEV;
#ifdef CONFIG_AS_AVX2
chacha_use_avx2 = boot_cpu_has(X86_FEATURE_AVX) &&
boot_cpu_has(X86_FEATURE_AVX2) &&
cpu_has_xfeatures(XFEATURE_MASK_SSE | XFEATURE_MASK_YMM, NULL);
#ifdef CONFIG_AS_AVX512
chacha_use_avx512vl = chacha_use_avx2 &&
boot_cpu_has(X86_FEATURE_AVX512VL) &&
boot_cpu_has(X86_FEATURE_AVX512BW); /* kmovq */
#endif
#endif
return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
}
static void __exit chacha_simd_mod_fini(void)
{
crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
}
module_init(chacha_simd_mod_init);
module_exit(chacha_simd_mod_fini);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (x64 SIMD accelerated)");
MODULE_ALIAS_CRYPTO("chacha20");
MODULE_ALIAS_CRYPTO("chacha20-simd");
MODULE_ALIAS_CRYPTO("xchacha20");
MODULE_ALIAS_CRYPTO("xchacha20-simd");
MODULE_ALIAS_CRYPTO("xchacha12");
MODULE_ALIAS_CRYPTO("xchacha12-simd");
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