[tip:perf/core] perf/x86/intel: Add quirk for Goldmont Plus

[tip-bot for Kan Liang]

Commit-ID:  7c5314b88da6d5af98239786772a1c44cc5eb67d
Gitweb:     https://git.kernel.org/tip/7c5314b88da6d5af98239786772a1c44cc5eb67d
Author:     Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
AuthorDate: Wed, 8 Aug 2018 00:12:08 -0700
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 2 Oct 2018 10:14:33 +0200

perf/x86/intel: Add quirk for Goldmont Plus

A ucode patch is needed for Goldmont Plus while counter freezing feature
is enabled. Otherwise, there will be some issues, e.g. PMI flood with
some events.

Add a quirk to check microcode version. If the system starts with the
wrong ucode, leave the counter-freezing feature permanently disabled.

Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Cc: acme@xxxxxxxxxx
Link: http://lkml.kernel.org/r/1533712328-2834-3-git-send-email-kan.liang@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/events/intel/core.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index f17cf6c3ec6f..ab01ef9ddd77 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3839,6 +3839,40 @@ static __init void intel_nehalem_quirk(void)
 	}
 }
 
+static bool intel_glp_counter_freezing_broken(int cpu)
+{
+	u32 rev = UINT_MAX; /* default to broken for unknown stepping */
+
+	switch (cpu_data(cpu).x86_stepping) {
+	case 1:
+		rev = 0x28;
+		break;
+	case 8:
+		rev = 0x6;
+		break;
+	}
+
+	return (cpu_data(cpu).microcode < rev);
+}
+
+static __init void intel_glp_counter_freezing_quirk(void)
+{
+	/* Check if it's already disabled */
+	if (disable_counter_freezing)
+		return;
+
+	/*
+	 * If the system starts with the wrong ucode, leave the
+	 * counter-freezing feature permanently disabled.
+	 */
+	if (intel_glp_counter_freezing_broken(raw_smp_processor_id())) {
+		pr_info("PMU counter freezing disabled due to CPU errata,"
+			"please upgrade microcode\n");
+		x86_pmu.counter_freezing = false;
+		x86_pmu.handle_irq = intel_pmu_handle_irq;
+	}
+}
+
 /*
  * enable software workaround for errata:
  * SNB: BJ122
@@ -4188,6 +4222,7 @@ __init int intel_pmu_init(void)
 		break;
 
 	case INTEL_FAM6_ATOM_GOLDMONT_PLUS:
+		x86_add_quirk(intel_glp_counter_freezing_quirk);
 		memcpy(hw_cache_event_ids, glp_hw_cache_event_ids,
 		       sizeof(hw_cache_event_ids));
 		memcpy(hw_cache_extra_regs, glp_hw_cache_extra_regs,