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0bc81767c5
When the ARM accelerated ChaCha driver is built as part of a configuration
that has kernel mode NEON disabled, we expect the compiler to propagate
the build time constant expression IS_ENABLED(CONFIG_KERNEL_MODE_NEON) in
a way that eliminates all the cross-object references to the actual NEON
routines, which allows the chacha-neon-core.o object to be omitted from
the build entirely.
Unfortunately, this fails to work as expected in some cases, and we may
end up with a build error such as
chacha-glue.c:(.text+0xc0): undefined reference to `chacha_4block_xor_neon'
caused by the fact that chacha_doneon() has not been eliminated from the
object code, even though it will never be called in practice.
Let's fix this by adding some IS_ENABLED(CONFIG_KERNEL_MODE_NEON) tests
that are not strictly needed from a logical point of view, but should
help the compiler infer that the NEON code paths are unreachable in
those cases.
Fixes: b36d8c09e7 ("crypto: arm/chacha - remove dependency on generic ...")
Reported-by: Russell King <linux@armlinux.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
350 lines
9.4 KiB
C
350 lines
9.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* ARM NEON accelerated ChaCha and XChaCha stream ciphers,
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* including ChaCha20 (RFC7539)
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*
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* Copyright (C) 2016-2019 Linaro, Ltd. <ard.biesheuvel@linaro.org>
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* Copyright (C) 2015 Martin Willi
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*/
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#include <crypto/algapi.h>
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#include <crypto/internal/chacha.h>
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#include <crypto/internal/simd.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/jump_label.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <asm/cputype.h>
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#include <asm/hwcap.h>
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#include <asm/neon.h>
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#include <asm/simd.h>
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asmlinkage void chacha_block_xor_neon(const u32 *state, u8 *dst, const u8 *src,
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int nrounds);
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asmlinkage void chacha_4block_xor_neon(const u32 *state, u8 *dst, const u8 *src,
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int nrounds);
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asmlinkage void hchacha_block_arm(const u32 *state, u32 *out, int nrounds);
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asmlinkage void hchacha_block_neon(const u32 *state, u32 *out, int nrounds);
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asmlinkage void chacha_doarm(u8 *dst, const u8 *src, unsigned int bytes,
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const u32 *state, int nrounds);
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static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_neon);
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static inline bool neon_usable(void)
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{
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return static_branch_likely(&use_neon) && crypto_simd_usable();
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}
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static void chacha_doneon(u32 *state, u8 *dst, const u8 *src,
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unsigned int bytes, int nrounds)
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{
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u8 buf[CHACHA_BLOCK_SIZE];
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while (bytes >= CHACHA_BLOCK_SIZE * 4) {
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chacha_4block_xor_neon(state, dst, src, nrounds);
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bytes -= CHACHA_BLOCK_SIZE * 4;
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src += CHACHA_BLOCK_SIZE * 4;
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dst += CHACHA_BLOCK_SIZE * 4;
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state[12] += 4;
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}
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while (bytes >= CHACHA_BLOCK_SIZE) {
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chacha_block_xor_neon(state, dst, src, nrounds);
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bytes -= CHACHA_BLOCK_SIZE;
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src += CHACHA_BLOCK_SIZE;
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dst += CHACHA_BLOCK_SIZE;
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state[12]++;
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}
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if (bytes) {
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memcpy(buf, src, bytes);
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chacha_block_xor_neon(state, buf, buf, nrounds);
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memcpy(dst, buf, bytes);
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}
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}
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void hchacha_block_arch(const u32 *state, u32 *stream, int nrounds)
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{
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if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable()) {
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hchacha_block_arm(state, stream, nrounds);
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} else {
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kernel_neon_begin();
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hchacha_block_neon(state, stream, nrounds);
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kernel_neon_end();
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}
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}
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EXPORT_SYMBOL(hchacha_block_arch);
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void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv)
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{
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chacha_init_generic(state, key, iv);
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}
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EXPORT_SYMBOL(chacha_init_arch);
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void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src, unsigned int bytes,
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int nrounds)
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{
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if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable() ||
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bytes <= CHACHA_BLOCK_SIZE) {
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chacha_doarm(dst, src, bytes, state, nrounds);
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state[12] += DIV_ROUND_UP(bytes, CHACHA_BLOCK_SIZE);
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return;
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}
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kernel_neon_begin();
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chacha_doneon(state, dst, src, bytes, nrounds);
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kernel_neon_end();
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}
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EXPORT_SYMBOL(chacha_crypt_arch);
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static int chacha_stream_xor(struct skcipher_request *req,
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const struct chacha_ctx *ctx, const u8 *iv,
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bool neon)
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{
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struct skcipher_walk walk;
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u32 state[16];
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int err;
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err = skcipher_walk_virt(&walk, req, false);
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chacha_init_generic(state, ctx->key, iv);
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while (walk.nbytes > 0) {
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unsigned int nbytes = walk.nbytes;
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if (nbytes < walk.total)
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nbytes = round_down(nbytes, walk.stride);
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if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon) {
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chacha_doarm(walk.dst.virt.addr, walk.src.virt.addr,
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nbytes, state, ctx->nrounds);
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state[12] += DIV_ROUND_UP(nbytes, CHACHA_BLOCK_SIZE);
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} else {
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kernel_neon_begin();
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chacha_doneon(state, walk.dst.virt.addr,
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walk.src.virt.addr, nbytes, ctx->nrounds);
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kernel_neon_end();
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}
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err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
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}
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return err;
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}
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static int do_chacha(struct skcipher_request *req, bool neon)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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return chacha_stream_xor(req, ctx, req->iv, neon);
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}
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static int chacha_arm(struct skcipher_request *req)
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{
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return do_chacha(req, false);
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}
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static int chacha_neon(struct skcipher_request *req)
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{
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return do_chacha(req, neon_usable());
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}
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static int do_xchacha(struct skcipher_request *req, bool neon)
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{
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struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
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struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
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struct chacha_ctx subctx;
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u32 state[16];
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u8 real_iv[16];
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chacha_init_generic(state, ctx->key, req->iv);
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if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon) {
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hchacha_block_arm(state, subctx.key, ctx->nrounds);
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} else {
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kernel_neon_begin();
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hchacha_block_neon(state, subctx.key, ctx->nrounds);
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kernel_neon_end();
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}
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subctx.nrounds = ctx->nrounds;
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memcpy(&real_iv[0], req->iv + 24, 8);
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memcpy(&real_iv[8], req->iv + 16, 8);
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return chacha_stream_xor(req, &subctx, real_iv, neon);
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}
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static int xchacha_arm(struct skcipher_request *req)
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{
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return do_xchacha(req, false);
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}
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static int xchacha_neon(struct skcipher_request *req)
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{
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return do_xchacha(req, neon_usable());
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}
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static struct skcipher_alg arm_algs[] = {
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{
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.base.cra_name = "chacha20",
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.base.cra_driver_name = "chacha20-arm",
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.base.cra_priority = 200,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = CHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.setkey = chacha20_setkey,
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.encrypt = chacha_arm,
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.decrypt = chacha_arm,
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}, {
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.base.cra_name = "xchacha20",
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.base.cra_driver_name = "xchacha20-arm",
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.base.cra_priority = 200,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = XCHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.setkey = chacha20_setkey,
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.encrypt = xchacha_arm,
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.decrypt = xchacha_arm,
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}, {
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.base.cra_name = "xchacha12",
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.base.cra_driver_name = "xchacha12-arm",
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.base.cra_priority = 200,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = XCHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.setkey = chacha12_setkey,
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.encrypt = xchacha_arm,
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.decrypt = xchacha_arm,
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},
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};
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static struct skcipher_alg neon_algs[] = {
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{
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.base.cra_name = "chacha20",
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.base.cra_driver_name = "chacha20-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = CHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.walksize = 4 * CHACHA_BLOCK_SIZE,
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.setkey = chacha20_setkey,
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.encrypt = chacha_neon,
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.decrypt = chacha_neon,
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}, {
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.base.cra_name = "xchacha20",
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.base.cra_driver_name = "xchacha20-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = XCHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.walksize = 4 * CHACHA_BLOCK_SIZE,
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.setkey = chacha20_setkey,
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.encrypt = xchacha_neon,
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.decrypt = xchacha_neon,
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}, {
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.base.cra_name = "xchacha12",
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.base.cra_driver_name = "xchacha12-neon",
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.base.cra_priority = 300,
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.base.cra_blocksize = 1,
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.base.cra_ctxsize = sizeof(struct chacha_ctx),
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.base.cra_module = THIS_MODULE,
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.min_keysize = CHACHA_KEY_SIZE,
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.max_keysize = CHACHA_KEY_SIZE,
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.ivsize = XCHACHA_IV_SIZE,
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.chunksize = CHACHA_BLOCK_SIZE,
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.walksize = 4 * CHACHA_BLOCK_SIZE,
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.setkey = chacha12_setkey,
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.encrypt = xchacha_neon,
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.decrypt = xchacha_neon,
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}
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};
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static int __init chacha_simd_mod_init(void)
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{
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int err = 0;
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if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
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err = crypto_register_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
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if (err)
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return err;
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}
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if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON)) {
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int i;
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switch (read_cpuid_part()) {
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case ARM_CPU_PART_CORTEX_A7:
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case ARM_CPU_PART_CORTEX_A5:
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/*
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* The Cortex-A7 and Cortex-A5 do not perform well with
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* the NEON implementation but do incredibly with the
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* scalar one and use less power.
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*/
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for (i = 0; i < ARRAY_SIZE(neon_algs); i++)
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neon_algs[i].base.cra_priority = 0;
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break;
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default:
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static_branch_enable(&use_neon);
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}
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if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
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err = crypto_register_skciphers(neon_algs, ARRAY_SIZE(neon_algs));
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if (err)
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crypto_unregister_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
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}
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}
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return err;
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}
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static void __exit chacha_simd_mod_fini(void)
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{
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if (IS_REACHABLE(CONFIG_CRYPTO_SKCIPHER)) {
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crypto_unregister_skciphers(arm_algs, ARRAY_SIZE(arm_algs));
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if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON))
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crypto_unregister_skciphers(neon_algs, ARRAY_SIZE(neon_algs));
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}
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}
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module_init(chacha_simd_mod_init);
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module_exit(chacha_simd_mod_fini);
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MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (scalar and NEON accelerated)");
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS_CRYPTO("chacha20");
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MODULE_ALIAS_CRYPTO("chacha20-arm");
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MODULE_ALIAS_CRYPTO("xchacha20");
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MODULE_ALIAS_CRYPTO("xchacha20-arm");
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MODULE_ALIAS_CRYPTO("xchacha12");
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MODULE_ALIAS_CRYPTO("xchacha12-arm");
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#ifdef CONFIG_KERNEL_MODE_NEON
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MODULE_ALIAS_CRYPTO("chacha20-neon");
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MODULE_ALIAS_CRYPTO("xchacha20-neon");
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MODULE_ALIAS_CRYPTO("xchacha12-neon");
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#endif
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