56 lines
2.1 KiB
C
56 lines
2.1 KiB
C
/* Chacha20 implementation, used on arc4random.
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Copyright (C) 2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <isa-level.h>
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#include <ldsodefs.h>
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#include <cpu-features.h>
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#include <sys/param.h>
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unsigned int __chacha20_sse2_blocks4 (uint32_t *state, uint8_t *dst,
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const uint8_t *src, size_t nblks)
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attribute_hidden;
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unsigned int __chacha20_avx2_blocks8 (uint32_t *state, uint8_t *dst,
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const uint8_t *src, size_t nblks)
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attribute_hidden;
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static inline void
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chacha20_crypt (uint32_t *state, uint8_t *dst, const uint8_t *src,
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size_t bytes)
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{
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_Static_assert (CHACHA20_BUFSIZE % 4 == 0 && CHACHA20_BUFSIZE % 8 == 0,
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"CHACHA20_BUFSIZE not multiple of 4 or 8");
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_Static_assert (CHACHA20_BUFSIZE >= CHACHA20_BLOCK_SIZE * 8,
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"CHACHA20_BUFSIZE < CHACHA20_BLOCK_SIZE * 8");
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#if MINIMUM_X86_ISA_LEVEL > 2
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__chacha20_avx2_blocks8 (state, dst, src,
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CHACHA20_BUFSIZE / CHACHA20_BLOCK_SIZE);
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#else
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const struct cpu_features* cpu_features = __get_cpu_features ();
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/* AVX2 version uses vzeroupper, so disable it if RTM is enabled. */
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if (X86_ISA_CPU_FEATURE_USABLE_P (cpu_features, AVX2)
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&& X86_ISA_CPU_FEATURES_ARCH_P (cpu_features, Prefer_No_VZEROUPPER, !))
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__chacha20_avx2_blocks8 (state, dst, src,
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CHACHA20_BUFSIZE / CHACHA20_BLOCK_SIZE);
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else
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__chacha20_sse2_blocks4 (state, dst, src,
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CHACHA20_BUFSIZE / CHACHA20_BLOCK_SIZE);
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#endif
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}
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