From: Fenghua Yu Date: Fri, 25 May 2012 01:19:45 +0000 (-0700) Subject: x86/copy_user_generic: Optimize copy_user_generic with CPU erms feature X-Git-Tag: v3.6-rc1~164^2~2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=954e482bde20b0e208fd4d34ef26e10afd194600;p=pandora-kernel.git x86/copy_user_generic: Optimize copy_user_generic with CPU erms feature According to Intel 64 and IA-32 SDM and Optimization Reference Manual, beginning with Ivybridge, REG string operation using MOVSB and STOSB can provide both flexible and high-performance REG string operations in cases like memory copy. Enhancement availability is indicated by CPUID.7.0.EBX[9] (Enhanced REP MOVSB/ STOSB). If CPU erms feature is detected, patch copy_user_generic with enhanced fast string version of copy_user_generic. A few new macros are defined to reduce duplicate code in ALTERNATIVE and ALTERNATIVE_2. Signed-off-by: Fenghua Yu Link: http://lkml.kernel.org/r/1337908785-14015-1-git-send-email-fenghua.yu@intel.com Signed-off-by: H. Peter Anvin --- Reading git-diff-tree failed