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// SPDX-License-Identifier: GPL-2.0
/*
* ChaCha stream cipher (s390 optimized)
*
* Copyright IBM Corp. 2021
*/
#define KMSG_COMPONENT "chacha_s390"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <crypto/chacha.h>
#include <linux/cpufeature.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sizes.h>
#include <asm/fpu.h>
#include "chacha-s390.h"
void hchacha_block_arch(const struct chacha_state *state,
u32 out[HCHACHA_OUT_WORDS], int nrounds)
{
/* TODO: implement hchacha_block_arch() in assembly */
hchacha_block_generic(state, out, nrounds);
}
EXPORT_SYMBOL(hchacha_block_arch);
void chacha_crypt_arch(struct chacha_state *state, u8 *dst, const u8 *src,
unsigned int bytes, int nrounds)
{
/* s390 chacha20 implementation has 20 rounds hard-coded,
* it cannot handle a block of data or less, but otherwise
* it can handle data of arbitrary size
*/
if (bytes <= CHACHA_BLOCK_SIZE || nrounds != 20 || !cpu_has_vx()) {
chacha_crypt_generic(state, dst, src, bytes, nrounds);
} else {
DECLARE_KERNEL_FPU_ONSTACK32(vxstate);
kernel_fpu_begin(&vxstate, KERNEL_VXR);
chacha20_vx(dst, src, bytes, &state->x[4], &state->x[12]);
kernel_fpu_end(&vxstate, KERNEL_VXR);
state->x[12] += round_up(bytes, CHACHA_BLOCK_SIZE) /
CHACHA_BLOCK_SIZE;
}
}
EXPORT_SYMBOL(chacha_crypt_arch);
bool chacha_is_arch_optimized(void)
{
return cpu_has_vx();
}
EXPORT_SYMBOL(chacha_is_arch_optimized);
MODULE_DESCRIPTION("ChaCha stream cipher (s390 optimized)");
MODULE_LICENSE("GPL v2");
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