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/* SPDX-License-Identifier: GPL-2.0 */
/*
* ChaCha and HChaCha functions (ARM optimized)
*
* Copyright (C) 2016-2019 Linaro, Ltd. <ard.biesheuvel@linaro.org>
* Copyright (C) 2015 Martin Willi
*/
#include <crypto/internal/simd.h>
#include <linux/jump_label.h>
#include <linux/kernel.h>
#include <asm/cputype.h>
#include <asm/hwcap.h>
#include <asm/neon.h>
#include <asm/simd.h>
asmlinkage void chacha_block_xor_neon(const struct chacha_state *state,
u8 *dst, const u8 *src, int nrounds);
asmlinkage void chacha_4block_xor_neon(const struct chacha_state *state,
u8 *dst, const u8 *src,
int nrounds, unsigned int nbytes);
asmlinkage void hchacha_block_arm(const struct chacha_state *state,
u32 out[HCHACHA_OUT_WORDS], int nrounds);
asmlinkage void hchacha_block_neon(const struct chacha_state *state,
u32 out[HCHACHA_OUT_WORDS], int nrounds);
asmlinkage void chacha_doarm(u8 *dst, const u8 *src, unsigned int bytes,
const struct chacha_state *state, int nrounds);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(use_neon);
static inline bool neon_usable(void)
{
return static_branch_likely(&use_neon) && crypto_simd_usable();
}
static void chacha_doneon(struct chacha_state *state, u8 *dst, const u8 *src,
unsigned int bytes, int nrounds)
{
u8 buf[CHACHA_BLOCK_SIZE];
while (bytes > CHACHA_BLOCK_SIZE) {
unsigned int l = min(bytes, CHACHA_BLOCK_SIZE * 4U);
chacha_4block_xor_neon(state, dst, src, nrounds, l);
bytes -= l;
src += l;
dst += l;
state->x[12] += DIV_ROUND_UP(l, CHACHA_BLOCK_SIZE);
}
if (bytes) {
const u8 *s = src;
u8 *d = dst;
if (bytes != CHACHA_BLOCK_SIZE)
s = d = memcpy(buf, src, bytes);
chacha_block_xor_neon(state, d, s, nrounds);
if (d != dst)
memcpy(dst, buf, bytes);
state->x[12]++;
}
}
static void hchacha_block_arch(const struct chacha_state *state,
u32 out[HCHACHA_OUT_WORDS], int nrounds)
{
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable()) {
hchacha_block_arm(state, out, nrounds);
} else {
kernel_neon_begin();
hchacha_block_neon(state, out, nrounds);
kernel_neon_end();
}
}
static void chacha_crypt_arch(struct chacha_state *state, u8 *dst,
const u8 *src, unsigned int bytes, int nrounds)
{
if (!IS_ENABLED(CONFIG_KERNEL_MODE_NEON) || !neon_usable() ||
bytes <= CHACHA_BLOCK_SIZE) {
chacha_doarm(dst, src, bytes, state, nrounds);
state->x[12] += DIV_ROUND_UP(bytes, CHACHA_BLOCK_SIZE);
return;
}
do {
unsigned int todo = min_t(unsigned int, bytes, SZ_4K);
kernel_neon_begin();
chacha_doneon(state, dst, src, todo, nrounds);
kernel_neon_end();
bytes -= todo;
src += todo;
dst += todo;
} while (bytes);
}
#define chacha_mod_init_arch chacha_mod_init_arch
static void chacha_mod_init_arch(void)
{
if (IS_ENABLED(CONFIG_KERNEL_MODE_NEON) && (elf_hwcap & HWCAP_NEON)) {
switch (read_cpuid_part()) {
case ARM_CPU_PART_CORTEX_A7:
case ARM_CPU_PART_CORTEX_A5:
/*
* The Cortex-A7 and Cortex-A5 do not perform well with
* the NEON implementation but do incredibly with the
* scalar one and use less power.
*/
break;
default:
static_branch_enable(&use_neon);
}
}
}
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