From 00f554fadebb96877ad449758dc90303a9826afe Mon Sep 17 00:00:00 2001 From: Philippe Bergheaud Date: Wed, 30 Apr 2014 09:12:01 +1000 Subject: powerpc: memcpy optimization for 64bit LE Unaligned stores take alignment exceptions on POWER7 running in little-endian. This is a dumb little-endian base memcpy that prevents unaligned stores. Once booted the feature fixup code switches over to the VMX copy loops (which are already endian safe). The question is what we do before that switch over. The base 64bit memcpy takes alignment exceptions on POWER7 so we can't use it as is. Fixing the causes of alignment exception would slow it down, because we'd need to ensure all loads and stores are aligned either through rotate tricks or bytewise loads and stores. Either would be bad for all other 64bit platforms. [ I simplified the loop a bit - Anton ] Signed-off-by: Philippe Bergheaud Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/ppc_ksyms.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'arch/powerpc/kernel/ppc_ksyms.c') diff --git a/arch/powerpc/kernel/ppc_ksyms.c b/arch/powerpc/kernel/ppc_ksyms.c index 450850a49dc..48d17d6fca5 100644 --- a/arch/powerpc/kernel/ppc_ksyms.c +++ b/arch/powerpc/kernel/ppc_ksyms.c @@ -155,9 +155,7 @@ EXPORT_SYMBOL(__cmpdi2); #endif long long __bswapdi2(long long); EXPORT_SYMBOL(__bswapdi2); -#ifdef __BIG_ENDIAN__ EXPORT_SYMBOL(memcpy); -#endif EXPORT_SYMBOL(memset); EXPORT_SYMBOL(memmove); EXPORT_SYMBOL(memcmp); -- cgit v1.2.3-70-g09d2