perf/x86/intel/lbr: Use correct index to save/restore LBR_INFO with call stack

Andi Kleen · Ingo Molnar · commit e0573364b8c5 · 2015-08-04T10:16:59.000+02:00
Use the correct index to save/restore the LBR_INFO_x MSR in callstack mode. This is more a cleanup, as even with the wrong index the register was correctly saved/restored, and also LBR callgraph mode in perf tools do not really need anything in LBR_INFO. But still better to use the right index. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: acme@kernel.org Cc: eranian@google.com Cc: jolsa@redhat.com Link: http://lkml.kernel.org/r/1432786398-23861-5-git-send-email-andi@firstfloor.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -245,7 +245,7 @@ static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)
 		wrmsrl(x86_pmu.lbr_from + lbr_idx, task_ctx->lbr_from[i]);
 		wrmsrl(x86_pmu.lbr_to + lbr_idx, task_ctx->lbr_to[i]);
 		if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
-			wrmsrl(MSR_LBR_INFO_0 + i, task_ctx->lbr_info[i]);
+			wrmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);
 	}
 	task_ctx->lbr_stack_state = LBR_NONE;
 }
@@ -268,7 +268,7 @@ static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)
 		rdmsrl(x86_pmu.lbr_from + lbr_idx, task_ctx->lbr_from[i]);
 		rdmsrl(x86_pmu.lbr_to + lbr_idx, task_ctx->lbr_to[i]);
 		if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)
-			rdmsrl(MSR_LBR_INFO_0 + i, task_ctx->lbr_info[i]);
+			rdmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);
 	}
 	task_ctx->lbr_stack_state = LBR_VALID;
 }

Original file line number	Diff line number	Diff line change
`@@ -245,7 +245,7 @@ static void __intel_pmu_lbr_restore(struct x86_perf_task_context *task_ctx)`
`245`	`245`	`wrmsrl(x86_pmu.lbr_from + lbr_idx, task_ctx->lbr_from[i]);`
`246`	`246`	`wrmsrl(x86_pmu.lbr_to + lbr_idx, task_ctx->lbr_to[i]);`
`247`	`247`	`if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)`
`248`		`- wrmsrl(MSR_LBR_INFO_0 + i, task_ctx->lbr_info[i]);`
	`248`	`+ wrmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);`
`249`	`249`	`}`
`250`	`250`	`task_ctx->lbr_stack_state = LBR_NONE;`
`251`	`251`	`}`
`@@ -268,7 +268,7 @@ static void __intel_pmu_lbr_save(struct x86_perf_task_context *task_ctx)`
`268`	`268`	`rdmsrl(x86_pmu.lbr_from + lbr_idx, task_ctx->lbr_from[i]);`
`269`	`269`	`rdmsrl(x86_pmu.lbr_to + lbr_idx, task_ctx->lbr_to[i]);`
`270`	`270`	`if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_INFO)`
`271`		`- rdmsrl(MSR_LBR_INFO_0 + i, task_ctx->lbr_info[i]);`
	`271`	`+ rdmsrl(MSR_LBR_INFO_0 + lbr_idx, task_ctx->lbr_info[i]);`
`272`	`272`	`}`
`273`	`273`	`task_ctx->lbr_stack_state = LBR_VALID;`
`274`	`274`	`}`