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/* SPDX-License-Identifier: GPL-2.0 */
/*
* ChaCha stream cipher (s390 optimized)
*
* Copyright IBM Corp. 2021
*/
#include <linux/cpufeature.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/sizes.h>
#include <asm/fpu.h>
#include "chacha-s390.h"
#define hchacha_block_arch hchacha_block_generic /* not implemented yet */
static 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;
}
}
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