[PATCH v2 1/2] x86: Add support for the pcommit instruction

[Ross Zwisler]

Add support for the new pcommit instruction.  This instruction was
announced in the document "Intel Architecture Instruction Set Extensions
Programming Reference" with reference number 319433-022.

https://software.intel.com/sites/default/files/managed/0d/53/319433-022.pdf

Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: H Peter Anvin <h.peter.anvin@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
---
 arch/x86/include/asm/cpufeature.h    | 1 +
 arch/x86/include/asm/special_insns.h | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index bb9b258..dfdd689 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -220,6 +220,7 @@
 #define X86_FEATURE_RDSEED	( 9*32+18) /* The RDSEED instruction */
 #define X86_FEATURE_ADX		( 9*32+19) /* The ADCX and ADOX instructions */
 #define X86_FEATURE_SMAP	( 9*32+20) /* Supervisor Mode Access Prevention */
+#define X86_FEATURE_PCOMMIT	( 9*32+22) /* PCOMMIT instruction */
 #define X86_FEATURE_CLFLUSHOPT	( 9*32+23) /* CLFLUSHOPT instruction */
 #define X86_FEATURE_AVX512PF	( 9*32+26) /* AVX-512 Prefetch */
 #define X86_FEATURE_AVX512ER	( 9*32+27) /* AVX-512 Exponential and Reciprocal */
diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index e820c08..1709a2e 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -199,6 +199,12 @@ static inline void clflushopt(volatile void *__p)
 		       "+m" (*(volatile char __force *)__p));
 }
 
+static inline void pcommit(void)
+{
+	alternative(ASM_NOP4, ".byte 0x66, 0x0f, 0xae, 0xf8",
+		    X86_FEATURE_PCOMMIT);
+}
+
 #define nop() asm volatile ("nop")
 
 
-- 
1.9.3

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