[PATCH v3 1/2] x86/cpufeatures: Enumerate TSX suspend load address tracking instructions

From: Cathy Zhang
Date: Sun Aug 09 2020 - 03:53:15 EST


From: Kyung Min Park <kyung.min.park@xxxxxxxxx>

Intel TSX suspend load tracking instructions aim to give a way to
choose which memory accesses do not need to be tracked in the TSX
read set. Add TSX suspend load tracking CPUID feature flag TSXLDTRK
for enumeration.

A processor supports Intel TSX suspend load address tracking if
CPUID.0x07.0x0:EDX[16] is present. Two instructions XSUSLDTRK, XRESLDTRK
are available when this feature is present.

The CPU feature flag is shown as "tsxldtrk" in /proc/cpuinfo.

This instruction is currently documented in the the latest "extensions"
manual (ISE). It will appear in the "main" manual (SDM) in the future.

Signed-off-by: Kyung Min Park <kyung.min.park@xxxxxxxxx>
Signed-off-by: Cathy Zhang <cathy.zhang@xxxxxxxxx>
Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
---
Changes since v2:
* Shorten documentation names for readability. Links to documentation
can be found in the cover letter. (Dave Hansen)
---
arch/x86/include/asm/cpufeatures.h | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 2901d5d..83fc9d3 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -368,6 +368,7 @@
#define X86_FEATURE_MD_CLEAR (18*32+10) /* VERW clears CPU buffers */
#define X86_FEATURE_TSX_FORCE_ABORT (18*32+13) /* "" TSX_FORCE_ABORT */
#define X86_FEATURE_SERIALIZE (18*32+14) /* SERIALIZE instruction */
+#define X86_FEATURE_TSXLDTRK (18*32+16) /* TSX Suspend Load Address Tracking */
#define X86_FEATURE_PCONFIG (18*32+18) /* Intel PCONFIG */
#define X86_FEATURE_ARCH_LBR (18*32+19) /* Intel ARCH LBR */
#define X86_FEATURE_SPEC_CTRL (18*32+26) /* "" Speculation Control (IBRS + IBPB) */
--
1.8.3.1