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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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12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182// SPDX-License-Identifier: GPL-2.0/* * This provides an optimized implementation of memcpy, and a simplified * implementation of memset and memmove. These are used here because the * standard kernel runtime versions are not yet available and we don't * trust the gcc built-in implementations as they may do unexpected things * (e.g. FPU ops) in the minimal decompression stub execution environment. */#include "error.h"
#include "../string.c"
#ifdef CONFIG_X86_32static void *____memcpy(void *dest, const void *src, size_t n){ int d0, d1, d2; asm volatile( "rep movsl\n\t" "movl %4,%%ecx\n\t" "rep movsb" : "=&c" (d0), "=&D" (d1), "=&S" (d2) : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src) : "memory");
return dest;}#elsestatic void *____memcpy(void *dest, const void *src, size_t n){ long d0, d1, d2; asm volatile( "rep movsq\n\t" "movq %4,%%rcx\n\t" "rep movsb" : "=&c" (d0), "=&D" (d1), "=&S" (d2) : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src) : "memory");
return dest;}#endif
void *memset(void *s, int c, size_t n){ int i; char *ss = s;
for (i = 0; i < n; i++) ss[i] = c; return s;}
void *memmove(void *dest, const void *src, size_t n){ unsigned char *d = dest; const unsigned char *s = src;
if (d <= s || d - s >= n) return ____memcpy(dest, src, n);
while (n-- > 0) d[n] = s[n];
return dest;}
/* Detect and warn about potential overlaps, but handle them with memmove. */void *memcpy(void *dest, const void *src, size_t n){ if (dest > src && dest - src < n) { warn("Avoiding potentially unsafe overlapping memcpy()!"); return memmove(dest, src, n); } return ____memcpy(dest, src, n);}
#ifdef CONFIG_KASANextern void *__memset(void *s, int c, size_t n) __alias(memset);extern void *__memmove(void *dest, const void *src, size_t n) __alias(memmove);extern void *__memcpy(void *dest, const void *src, size_t n) __alias(memcpy);#endif