Commit-ID: 81b785f3e4114ed74fceb48a54e7de2f797a2ba1 Gitweb: http://git.kernel.org/tip/81b785f3e4114ed74fceb48a54e7de2f797a2ba1 Author: Kees Cook <[email protected]> AuthorDate: Tue, 26 Apr 2016 14:46:06 -0700 Committer: Ingo Molnar <[email protected]> CommitDate: Thu, 28 Apr 2016 11:02:29 +0200
x86/boot: Rename overlapping memcpy() to memmove() 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 <[email protected]> Signed-off-by: Kees Cook <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Baoquan He <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: H.J. Lu <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Yinghai Lu <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/x86/boot/compressed/misc.c | 6 ++++-- arch/x86/boot/compressed/string.c | 19 +++++++++++-------- 2 files changed, 15 insertions(+), 10 deletions(-) diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c index c57d785..6dde6cc 100644 --- a/arch/x86/boot/compressed/misc.c +++ b/arch/x86/boot/compressed/misc.c @@ -32,9 +32,11 @@ #undef memcpy #undef memset #define memzero(s, n) memset((s), 0, (n)) +#define memmove memmove /* Functions used by the included decompressor code below. */ static void error(char *m); +void *memmove(void *dest, const void *src, size_t n); /* * This is set up by the setup-routine at boot-time @@ -80,7 +82,7 @@ static void scroll(void) { int i; - memcpy(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2); + memmove(vidmem, vidmem + cols * 2, (lines - 1) * cols * 2); for (i = (lines - 1) * cols * 2; i < lines * cols * 2; i += 2) vidmem[i] = ' '; } @@ -307,7 +309,7 @@ static void parse_elf(void *output) #else dest = (void *)(phdr->p_paddr); #endif - memcpy(dest, output + phdr->p_offset, phdr->p_filesz); + memmove(dest, output + phdr->p_offset, phdr->p_filesz); break; default: /* Ignore other PT_* */ break; } diff --git a/arch/x86/boot/compressed/string.c b/arch/x86/boot/compressed/string.c index 1e10e40..2befeca 100644 --- a/arch/x86/boot/compressed/string.c +++ b/arch/x86/boot/compressed/string.c @@ -1,7 +1,14 @@ +/* + * 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) +void *memcpy(void *dest, const void *src, size_t n) { int d0, d1, d2; asm volatile( @@ -15,7 +22,7 @@ void *__memcpy(void *dest, const void *src, size_t n) return dest; } #else -void *__memcpy(void *dest, const void *src, size_t n) +void *memcpy(void *dest, const void *src, size_t n) { long d0, d1, d2; asm volatile( @@ -40,17 +47,13 @@ void *memset(void *s, int c, size_t n) return s; } -/* - * This memcpy is overlap safe (i.e. it is memmove without conflicting - * with other definitions of memmove from the various decompressors. - */ -void *memcpy(void *dest, const void *src, size_t n) +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); + return memcpy(dest, src, n); while (n-- > 0) d[n] = s[n];
