perf/x86/intel: Add {rd,wr}lbr_{to,from} wrappers

The whole rdmsr()/wrmsr() for lbr_from got a little unweildy with the
sign extension quirk, provide a few simple wrappers to clean things up.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/events/intel/lbr.c

@@ -289,12 +289,42 @@ inline u64 lbr_from_signext_quirk_wr(u64 val)
  */
 u64 lbr_from_signext_quirk_rd(u64 val)
 {
-	if (static_branch_unlikely(&lbr_from_quirk_key))
+	if (static_branch_unlikely(&lbr_from_quirk_key)) {
 		/*
 		 * Quirk is on when TSX is not enabled. Therefore TSX
 		 * flags must be read as OFF.
 		 */
 		val &= ~(LBR_FROM_FLAG_IN_TX | LBR_FROM_FLAG_ABORT);
+	}
+	return val;
+}
+
+static inline void wrlbr_from(unsigned int idx, u64 val)
+{
+	val = lbr_from_signext_quirk_wr(val);
+	wrmsrl(x86_pmu.lbr_from + idx, val);
+}
+
+static inline void wrlbr_to(unsigned int idx, u64 val)
+{
+	wrmsrl(x86_pmu.lbr_to + idx, val);
+}
+
+static inline u64 rdlbr_from(unsigned int idx)
+{
+	u64 val;
+
+	rdmsrl(x86_pmu.lbr_from + idx, val);
+
+	return lbr_from_signext_quirk_rd(val);
+}
+
+static inline u64 rdlbr_to(unsigned int idx)
+{
+	u64 val;
+
+	rdmsrl(x86_pmu.lbr_from + idx, val);
+
 	return val;
 }
 
@@ -314,9 +344,9 @@ static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)
 	tos = task_ctx->tos;
 	for (i = 0; i < tos; i++) {
 		lbr_idx = (tos - i) & mask;
-		wrmsrl(x86_pmu.lbr_from + lbr_idx,
-			lbr_from_signext_quirk_wr(task_ctx->lbr_from[i]));
-		wrmsrl(x86_pmu.lbr_to + lbr_idx, task_ctx->lbr_to[i]);
+		wrlbr_from(lbr_idx, task_ctx->lbr_from[i]);
+		wrlbr_to  (lbr_idx, task_ctx->lbr_to[i]);
+
 		if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
 			wrmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);
 	}
@@ -326,9 +356,9 @@ static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)
 
 static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
 {
-	int i;
 	unsigned lbr_idx, mask;
-	u64 tos, val;
+	u64 tos;
+	int i;
 
 	if (task_ctx->lbr_callstack_users == 0) {
 		task_ctx->lbr_stack_state = LBR_NONE;
@@ -339,9 +369,8 @@ static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
 	tos = intel_pmu_lbr_tos();
 	for (i = 0; i < tos; i++) {
 		lbr_idx = (tos - i) & mask;
-		rdmsrl(x86_pmu.lbr_from + lbr_idx, val);
-		task_ctx->lbr_from[i] = lbr_from_signext_quirk_rd(val);
-		rdmsrl(x86_pmu.lbr_to + lbr_idx, task_ctx->lbr_to[i]);
+		task_ctx->lbr_from[i] = rdlbr_from(lbr_idx);
+		task_ctx->lbr_to[i]   = rdlbr_to(lbr_idx);
 		if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
 			rdmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);
 	}
@@ -517,10 +546,8 @@ static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
 		u16 cycles = 0;
 		int lbr_flags = lbr_desc[lbr_format];
 
-		rdmsrl(x86_pmu.lbr_from + lbr_idx, from);
-		from = lbr_from_signext_quirk_rd(from);
-
-		rdmsrl(x86_pmu.lbr_to   + lbr_idx, to);
+		from = rdlbr_from(lbr_idx);
+		to   = rdlbr_to(lbr_idx);
 
 		if (lbr_format == LBR_FORMAT_INFO && need_info) {
 			u64 info;