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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091// SPDX-License-Identifier: GPL-2.0-or-later/* * Crypto library utility functions * * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au> */
#include <crypto/utils.h>#include <linux/export.h>#include <linux/module.h>#include <linux/unaligned.h>
/* * XOR @len bytes from @src1 and @src2 together, writing the result to @dst * (which may alias one of the sources). Don't call this directly; call * crypto_xor() or crypto_xor_cpy() instead. */void __crypto_xor(u8 *dst, const u8 *src1, const u8 *src2, unsigned int len){ int relalign = 0;
if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { int size = sizeof(unsigned long); int d = (((unsigned long)dst ^ (unsigned long)src1) | ((unsigned long)dst ^ (unsigned long)src2)) & (size - 1);
relalign = d ? 1 << __ffs(d) : size;
/* * If we care about alignment, process as many bytes as * needed to advance dst and src to values whose alignments * equal their relative alignment. This will allow us to * process the remainder of the input using optimal strides. */ while (((unsigned long)dst & (relalign - 1)) && len > 0) { *dst++ = *src1++ ^ *src2++; len--; } }
while (IS_ENABLED(CONFIG_64BIT) && len >= 8 && !(relalign & 7)) { if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { u64 l = get_unaligned((u64 *)src1) ^ get_unaligned((u64 *)src2); put_unaligned(l, (u64 *)dst); } else { *(u64 *)dst = *(u64 *)src1 ^ *(u64 *)src2; } dst += 8; src1 += 8; src2 += 8; len -= 8; }
while (len >= 4 && !(relalign & 3)) { if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { u32 l = get_unaligned((u32 *)src1) ^ get_unaligned((u32 *)src2); put_unaligned(l, (u32 *)dst); } else { *(u32 *)dst = *(u32 *)src1 ^ *(u32 *)src2; } dst += 4; src1 += 4; src2 += 4; len -= 4; }
while (len >= 2 && !(relalign & 1)) { if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) { u16 l = get_unaligned((u16 *)src1) ^ get_unaligned((u16 *)src2); put_unaligned(l, (u16 *)dst); } else { *(u16 *)dst = *(u16 *)src1 ^ *(u16 *)src2; } dst += 2; src1 += 2; src2 += 2; len -= 2; }
while (len--) *dst++ = *src1++ ^ *src2++;}EXPORT_SYMBOL_GPL(__crypto_xor);
MODULE_DESCRIPTION("Crypto library utility functions");MODULE_LICENSE("GPL");