Commit 5b3e83f4 authored by Fenghua Yu's avatar Fenghua Yu Committed by H. Peter Anvin

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: default avatarFenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1401387164-43416-5-git-send-email-fenghua.yu@intel.comSigned-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent b6f42a4a
...@@ -161,6 +161,20 @@ static inline int alternatives_text_reserved(void *start, void *end) ...@@ -161,6 +161,20 @@ static inline int alternatives_text_reserved(void *start, void *end)
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
: : "i" (0), ## input) : : "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 */ /* Like alternative_input, but with a single output argument */
#define alternative_io(oldinstr, newinstr, feature, output, input...) \ #define alternative_io(oldinstr, newinstr, feature, output, input...) \
asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \
......
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