Add alternative_io_2 in the spirit of alternative_input_2 and alternative_io. This will allow us to have instructions with an output parameter that vary based on two CPU features.
Signed-off-by: Ross Zwisler ross.zwisler@linux.intel.com Cc: H Peter Anvin h.peter.anvin@intel.com Cc: Ingo Molnar mingo@kernel.org Cc: Thomas Gleixner tglx@linutronix.de Cc: David Airlie airlied@linux.ie Cc: dri-devel@lists.freedesktop.org Cc: x86@kernel.org --- 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 473bdbe..7d9ead9 100644 --- a/arch/x86/include/asm/alternative.h +++ b/arch/x86/include/asm/alternative.h @@ -180,6 +180,20 @@ static inline int alternatives_text_reserved(void *start, void *end) asm volatile (ALTERNATIVE(oldinstr, newinstr, feature) \ : output : "i" (0), ## input)
+/* + * This is similar to alternative_io. 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_io_2(oldinstr, newinstr1, feature1, newinstr2, \ + feature2, output, input...) \ + asm volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, \ + newinstr2, feature2) \ + : output : "i" (0), ## input) + /* Like alternative_io, but for replacing a direct call with another one. */ #define alternative_call(oldfunc, newfunc, feature, output, input...) \ asm volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \