perf/x86/intel/lbr: Add a function pointer for LBR reset

The method to reset Architectural LBRs is different from previous
model-specific LBR. Perf has to implement a different function.

A function pointer is introduced for LBR reset. The enum of
LBR_FORMAT_* is also moved to perf_event.h. Perf should initialize the
corresponding functions at boot time, and avoid checking lbr_format at
run time.

The current 64-bit LBR reset function is set as default.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/1593780569-62993-3-git-send-email-kan.liang@linux.intel.com

arch/x86/events/intel/core.c

@@ -3978,6 +3978,8 @@ static __initconst const struct x86_pmu core_pmu = {
 	.cpu_dead		= intel_pmu_cpu_dead,
 
 	.check_period		= intel_pmu_check_period,
+
+	.lbr_reset		= intel_pmu_lbr_reset_64,
 };
 
 static __initconst const struct x86_pmu intel_pmu = {
@@ -4023,6 +4025,8 @@ static __initconst const struct x86_pmu intel_pmu = {
 	.check_period		= intel_pmu_check_period,
 
 	.aux_output_match	= intel_pmu_aux_output_match,
+
+	.lbr_reset		= intel_pmu_lbr_reset_64,
 };
 
 static __init void intel_clovertown_quirk(void)
@@ -4649,6 +4653,9 @@ __init int intel_pmu_init(void)
 		x86_pmu.intel_cap.capabilities = capabilities;
 	}
 
+	if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_32)
+		x86_pmu.lbr_reset = intel_pmu_lbr_reset_32;
+
 	intel_ds_init();
 
 	x86_add_quirk(intel_arch_events_quirk); /* Install first, so it runs last */

arch/x86/events/intel/lbr.c

@@ -8,17 +8,6 @@
 
 #include "../perf_event.h"
 
-enum {
-	LBR_FORMAT_32		= 0x00,
-	LBR_FORMAT_LIP		= 0x01,
-	LBR_FORMAT_EIP		= 0x02,
-	LBR_FORMAT_EIP_FLAGS	= 0x03,
-	LBR_FORMAT_EIP_FLAGS2	= 0x04,
-	LBR_FORMAT_INFO		= 0x05,
-	LBR_FORMAT_TIME		= 0x06,
-	LBR_FORMAT_MAX_KNOWN    = LBR_FORMAT_TIME,
-};
-
 static const enum {
 	LBR_EIP_FLAGS		= 1,
 	LBR_TSX			= 2,
@@ -194,15 +183,15 @@ static void __intel_pmu_lbr_disable(void)
 	wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctl);
 }
 
-static void intel_pmu_lbr_reset_32(void)
+void intel_pmu_lbr_reset_32(void)
 {
 	int i;
 
 	for (i = 0; i < x86_pmu.lbr_nr; i++)
 		wrmsrl(x86_pmu.lbr_from + i, 0);
 }
 
-static void intel_pmu_lbr_reset_64(void)
+void intel_pmu_lbr_reset_64(void)
 {
 	int i;
 
@@ -221,10 +210,7 @@ void intel_pmu_lbr_reset(void)
 	if (!x86_pmu.lbr_nr)
 		return;
 
-	if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_32)
-		intel_pmu_lbr_reset_32();
-	else
-		intel_pmu_lbr_reset_64();
+	x86_pmu.lbr_reset();
 
 	cpuc->last_task_ctx = NULL;
 	cpuc->last_log_id = 0;

arch/x86/events/perf_event.h

@@ -179,6 +179,17 @@ struct intel_excl_cntrs {
 struct x86_perf_task_context;
 #define MAX_LBR_ENTRIES		32
 
+enum {
+	LBR_FORMAT_32		= 0x00,
+	LBR_FORMAT_LIP		= 0x01,
+	LBR_FORMAT_EIP		= 0x02,
+	LBR_FORMAT_EIP_FLAGS	= 0x03,
+	LBR_FORMAT_EIP_FLAGS2	= 0x04,
+	LBR_FORMAT_INFO		= 0x05,
+	LBR_FORMAT_TIME		= 0x06,
+	LBR_FORMAT_MAX_KNOWN    = LBR_FORMAT_TIME,
+};
+
 enum {
 	X86_PERF_KFREE_SHARED = 0,
 	X86_PERF_KFREE_EXCL   = 1,
@@ -682,6 +693,8 @@ struct x86_pmu {
 	bool		lbr_double_abort;	   /* duplicated lbr aborts */
 	bool		lbr_pt_coexist;		   /* (LBR|BTS) may coexist with PT */
 
+	void		(*lbr_reset)(void);
+
 	/*
 	 * Intel PT/LBR/BTS are exclusive
 	 */
@@ -1058,6 +1071,10 @@ u64 lbr_from_signext_quirk_wr(u64 val);
 
 void intel_pmu_lbr_reset(void);
 
+void intel_pmu_lbr_reset_32(void);
+
+void intel_pmu_lbr_reset_64(void);
+
 void intel_pmu_lbr_add(struct perf_event *event);
 
 void intel_pmu_lbr_del(struct perf_event *event);