perf/x86/intel: Implement support for TSX Force Abort
Skylake (and later) will receive a microcode update to address a TSX
errata. This microcode will, on execution of a TSX instruction
(speculative or not) use (clobber) PMC3. This update will also provide
a new MSR to change this behaviour along with a CPUID bit to enumerate
the presence of this new MSR.
When the MSR gets set; the microcode will no longer use PMC3 but will
Force Abort every TSX transaction (upon executing COMMIT).
When TSX Force Abort (TFA) is allowed (default); the MSR gets set when
PMC3 gets scheduled and cleared when, after scheduling, PMC3 is
unused.
When TFA is not allowed; clear PMC3 from all constraints such that it
will not get used.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 964212b..a345d07 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -243,6 +243,11 @@ struct cpu_hw_events {
int excl_thread_id; /* 0 or 1 */
/*
+ * SKL TSX_FORCE_ABORT shadow
+ */
+ u64 tfa_shadow;
+
+ /*
* AMD specific bits
*/
struct amd_nb *amd_nb;
@@ -681,6 +686,7 @@ do { \
#define PMU_FL_EXCL_CNTRS 0x4 /* has exclusive counter requirements */
#define PMU_FL_EXCL_ENABLED 0x8 /* exclusive counter active */
#define PMU_FL_PEBS_ALL 0x10 /* all events are valid PEBS events */
+#define PMU_FL_TFA 0x20 /* deal with TSX force abort */
#define EVENT_VAR(_id) event_attr_##_id
#define EVENT_PTR(_id) &event_attr_##_id.attr.attr