Commit e79dbf03 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'perf-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 perf event fix from Ingo Molnar:
 "Work around a firmware bug in the uncore PMU driver, affecting certain
  Intel systems"

* tag 'perf-urgent-2023-09-10' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/uncore: Correct the number of CHAs on EMR
parents 535a265d 6f7f984f

arch/x86/events/intel/uncore_snbep.c

+11 −1
Original line number Diff line number Diff line
@@ -6474,7 +6474,17 @@ void spr_uncore_cpu_init(void) 


	type = uncore_find_type_by_id(uncore_msr_uncores, UNCORE_SPR_CHA);

	if (type) {

		/*

		 * The value from the discovery table (stored in the type->num_boxes

		 * of UNCORE_SPR_CHA) is incorrect on some SPR variants because of a

		 * firmware bug. Using the value from SPR_MSR_UNC_CBO_CONFIG to replace it.

		 */

		rdmsrl(SPR_MSR_UNC_CBO_CONFIG, num_cbo);

		/*

		 * The MSR doesn't work on the EMR XCC, but the firmware bug doesn't impact

		 * the EMR XCC. Don't let the value from the MSR replace the existing value.

		 */

		if (num_cbo)

			type->num_boxes = num_cbo;

	}

	spr_uncore_iio_free_running.num_boxes = uncore_type_max_boxes(uncore_msr_uncores, UNCORE_SPR_IIO);