FAILED: patch "[PATCH] perf/x86/intel: Remove anythread_deprecated bit from" failed to apply to 6.6-stable tree

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 8767b4d73018bd3143f4c55b672064fad292f11b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026090959-popper-rotunda-e863@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 8767b4d73018bd3143f4c55b672064fad292f11b Mon Sep 17 00:00:00 2001
From: Dapeng Mi <[email protected]>
Date: Tue, 16 Jun 2026 12:46:47 +0800
Subject: [PATCH] perf/x86/intel: Remove anythread_deprecated bit from
perf_capabilities

AnyThread mode deprecation is enumerated by CPUID.0AH:EDX[15] instead of PERF_CAPABILITIES MSR. It's not a good practice to define a bit to represent "anythread deprecation" in perf_capabilities. It leads to the anythread_deprecated bit could be overwritten by the real value of PERF_CAPABILITIES MSR, just like the below code in update_pmu_cap() does.

if (!intel_pmu_broken_perf_cap()) {
	/* Perf Metric (Bit 15) and PEBS via PT (Bit 16) are hybrid enumeration */
	rdmsrq(MSR_IA32_PERF_CAPABILITIES, hybrid(pmu, intel_cap).capabilities);
}

It leads to the anythread_deprecated bit is cleared to 0 and the "any" attribute is incorrectly shown in the /sys/devices/cpu/format/ folder on these support Perfmon v6 platforms, like Clearwater Forest.

$ grep . /sys/devices/cpu/format/*
/sys/devices/cpu/format/acr_mask:config2:0-63
/sys/devices/cpu/format/any:config:21
/sys/devices/cpu/format/cmask:config:24-31

So remove the anythread_deprecated bit from perf_capabilities structure and directly depends on CPUID.0AH:EDX[15] to judge if anythread is deprecated.

index 2b35483e2b70..465c414f145d 100644
@@ -7947,12 +7947,6 @@ __init int intel_pmu_init(void)
 
 	x86_add_quirk(intel_arch_events_quirk); /* Install first, so it runs last */
 
-	if (version >= 5) {
-		x86_pmu.intel_cap.anythread_deprecated = edx.split.anythread_deprecated;
-		if (x86_pmu.intel_cap.anythread_deprecated)
-			pr_cont(" AnyThread deprecated, ");
-	}
-
 	/* The perf side of core PMU is ready to support the mediated vPMU. */
 	x86_get_pmu(smp_processor_id())->capabilities |= PERF_PMU_CAP_MEDIATED_VPMU;
 

@@ -8829,8 +8823,10 @@ __init int intel_pmu_init(void)
 				      &x86_pmu.intel_ctrl);
 
 	/* AnyThread may be deprecated on arch perfmon v5 or later */
-	if (x86_pmu.intel_cap.anythread_deprecated)
+	if (version >= 5 && edx.split.anythread_deprecated) {
 		x86_pmu.format_attrs = intel_arch_formats_attr;
+		pr_cont("AnyThread deprecated, ");
+	}
 
 	intel_pmu_check_event_constraints_all(NULL);
 

index eae24bb35dc1..5902a297daa1 100644
@@ -668,7 +668,7 @@ union perf_capabilities {
 		u64	perf_metrics:1;
 		u64	pebs_output_pt_available:1;
 		u64	pebs_timing_info:1;
-		u64	anythread_deprecated:1;
+		u64	__reserved:1;
 		u64	rdpmc_metrics_clear:1;
 	};
 	u64	capabilities;

From: Dapeng Mi <[email protected]>

[ Upstream commit 8767b4d73018bd3143f4c55b672064fad292f11b ]

AnyThread mode deprecation is enumerated by CPUID.0AH:EDX[15] instead of PERF_CAPABILITIES MSR. It's not a good practice to define a bit to represent "anythread deprecation" in perf_capabilities. It leads to the anythread_deprecated bit could be overwritten by the real value of PERF_CAPABILITIES MSR, just like the below code in update_pmu_cap() does.

if (!intel_pmu_broken_perf_cap()) {
	/* Perf Metric (Bit 15) and PEBS via PT (Bit 16) are hybrid enumeration */
	rdmsrq(MSR_IA32_PERF_CAPABILITIES, hybrid(pmu, intel_cap).capabilities);
}

It leads to the anythread_deprecated bit is cleared to 0 and the "any" attribute is incorrectly shown in the /sys/devices/cpu/format/ folder on these support Perfmon v6 platforms, like Clearwater Forest.

$ grep . /sys/devices/cpu/format/*
/sys/devices/cpu/format/acr_mask:config2:0-63
/sys/devices/cpu/format/any:config:21
/sys/devices/cpu/format/cmask:config:24-31

So remove the anythread_deprecated bit from perf_capabilities structure and directly depends on CPUID.0AH:EDX[15] to judge if anythread is deprecated.

---
 arch/x86/events/intel/core.c | 10 +++-------
 arch/x86/events/perf_event.h |  2 +-
 2 files changed, 4 insertions(+), 8 deletions(-)

index 8d1ec1d888da7..2c3d1f645fc24 100644
@@ -6155,12 +6155,6 @@ __init int intel_pmu_init(void)
 
 	x86_add_quirk(intel_arch_events_quirk); /* Install first, so it runs last */
 
-	if (version >= 5) {
-		x86_pmu.intel_cap.anythread_deprecated = edx.split.anythread_deprecated;
-		if (x86_pmu.intel_cap.anythread_deprecated)
-			pr_cont(" AnyThread deprecated, ");
-	}
-
 	/*
 	 * Install the hw-cache-events table:
 	 */

@@ -6951,8 +6945,10 @@ __init int intel_pmu_init(void)
 				     (u64)fixed_mask);
 
 	/* AnyThread may be deprecated on arch perfmon v5 or later */
-	if (x86_pmu.intel_cap.anythread_deprecated)
+	if (version >= 5 && edx.split.anythread_deprecated) {
 		x86_pmu.format_attrs = intel_arch_formats_attr;
+		pr_cont("AnyThread deprecated, ");
+	}
 
 	intel_pmu_check_event_constraints(x86_pmu.event_constraints,
 					  x86_pmu.num_counters,

index 4ca15be45cb80..9837e8d0deb39 100644
@@ -609,7 +609,7 @@ union perf_capabilities {
 		u64	perf_metrics:1;
 		u64	pebs_output_pt_available:1;
 		u64	pebs_timing_info:1;
-		u64	anythread_deprecated:1;
+		u64	__reserved:1;
 	};
 	u64	capabilities;
 };

2.53.0