81b785f3e4
Instead of having non-standard memcpy() behavior, explicitly call the new function memmove(), make it available to the decompressors, and switch the two overlap cases (screen scrolling and ELF parsing) to use memmove(). Additionally documents the purpose of compressed/string.c. Suggested-by: Lasse Collin <lasse.collin@tukaani.org> Signed-off-by: Kees Cook <keescook@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Borislav Petkov <bp@suse.de> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: H.J. Lu <hjl.tools@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yinghai Lu <yinghai@kernel.org> Link: http://lkml.kernel.org/r/20160426214606.GA5758@www.outflux.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
63 lines
1.3 KiB
C
63 lines
1.3 KiB
C
/*
|
|
* 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 "../string.c"
|
|
|
|
#ifdef CONFIG_X86_32
|
|
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\n\t"
|
|
: "=&c" (d0), "=&D" (d1), "=&S" (d2)
|
|
: "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
|
|
: "memory");
|
|
|
|
return dest;
|
|
}
|
|
#else
|
|
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\n\t"
|
|
: "=&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;
|
|
}
|