From 5b3e83f46a2a7e8625258dbf84a26e7f4032bfa8 Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Thu, 29 May 2014 11:12:32 -0700 Subject: [PATCH] x86/alternative: Add alternative_input_2 to support alternative with two features and input alternative_input_2() replaces old instruction with new instructions with input based on two features. In alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, feature2, input...), feature2 has higher priority to replace oldinstr than feature1. If CPU has feature2, newinstr2 replaces oldinstr and newinstr2 is executed during run time. If CPU doesn't have feature2, but it has feature1, newinstr1 replaces oldinstr and newinstr1 is executed during run time. If CPU doesn't have feature2 and feature1, oldinstr is executed during run time. Signed-off-by: Fenghua Yu Link: http://lkml.kernel.org/r/1401387164-43416-5-git-send-email-fenghua.yu@intel.com Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/alternative.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/x86/include/asm/alternative.h b/arch/x86/include/asm/alternative.h index 0a3f9c9f98d5..473bdbee378a 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -161,6 +161,20 @@ static inline int alternatives_text_reserved(void *start, void *end) asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ : : "i" (0), ## input) +/* + * This is similar to alternative_input. But it has two features and + * respective instructions. + * + * If CPU has feature2, newinstr2 is used. + * Otherwise, if CPU has feature1, newinstr1 is used. + * Otherwise, oldinstr is used. + */ +#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2, \ + feature2, input...) \ + asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \ + newinstr2, feature2) \ + : : "i" (0), ## input) + /* Like alternative_input, but with a single output argument */ #define alternative_io(oldinstr, newinstr, feature, output, input...) \ asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \