mirror of https://github.com/torvalds/linux.git
37 lines
1.0 KiB
C
37 lines
1.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* ChaCha stream cipher (s390 optimized)
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*
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* Copyright IBM Corp. 2021
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*/
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#include <linux/cpufeature.h>
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#include <linux/export.h>
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#include <linux/kernel.h>
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#include <linux/sizes.h>
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#include <asm/fpu.h>
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#include "chacha-s390.h"
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#define hchacha_block_arch hchacha_block_generic /* not implemented yet */
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static void chacha_crypt_arch(struct chacha_state *state, u8 *dst,
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const u8 *src, unsigned int bytes, int nrounds)
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{
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/* s390 chacha20 implementation has 20 rounds hard-coded,
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* it cannot handle a block of data or less, but otherwise
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* it can handle data of arbitrary size
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*/
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if (bytes <= CHACHA_BLOCK_SIZE || nrounds != 20 || !cpu_has_vx()) {
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chacha_crypt_generic(state, dst, src, bytes, nrounds);
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} else {
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DECLARE_KERNEL_FPU_ONSTACK32(vxstate);
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kernel_fpu_begin(&vxstate, KERNEL_VXR);
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chacha20_vx(dst, src, bytes, &state->x[4], &state->x[12]);
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kernel_fpu_end(&vxstate, KERNEL_VXR);
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state->x[12] += round_up(bytes, CHACHA_BLOCK_SIZE) /
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CHACHA_BLOCK_SIZE;
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}
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}
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