linux-kernel - [PATCH 04/21] perf/x86/intel/lbr: Add pointer for LBR read

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Date:   Fri, 19 Jun 2020 07:03:52 -0700
From:   kan.liang@...ux.intel.com
To:     peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        tglx@...utronix.de, bp@...en8.de, x86@...nel.org,
        linux-kernel@...r.kernel.org
Cc:     mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, namhyung@...nel.org, dave.hansen@...el.com,
        yu-cheng.yu@...el.com, bigeasy@...utronix.de, gorcunov@...il.com,
        hpa@...or.com, alexey.budankov@...ux.intel.com, eranian@...gle.com,
        ak@...ux.intel.com, like.xu@...ux.intel.com,
        yao.jin@...ux.intel.com, Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH 04/21] perf/x86/intel/lbr: Add pointer for LBR read

From: Kan Liang <kan.liang@...ux.intel.com>

The method to read Architectural LBRs is different from previous
model-specific LBR. Perf has to implement a different function.

A function pointer for LBR read is introduced. Perf should initialize
the corresponding function at boot time, and avoid checking lbr_format
at run time.

The current 64-bit LBR read function is set as default.

Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
---
 arch/x86/events/intel/core.c | 6 +++++-
 arch/x86/events/intel/lbr.c  | 9 +++------
 arch/x86/events/perf_event.h | 5 +++++
 3 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 995acdb..03b17d5 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -3955,6 +3955,7 @@ static __initconst const struct x86_pmu core_pmu = {
 	.lbr_enable		= intel_pmu_lbr_enable,
 	.lbr_disable		= intel_pmu_lbr_disable,
 	.lbr_reset		= intel_pmu_lbr_reset_64,
+	.lbr_read		= intel_pmu_lbr_read_64,
 };
 
 static __initconst const struct x86_pmu intel_pmu = {
@@ -4004,6 +4005,7 @@ static __initconst const struct x86_pmu intel_pmu = {
 	.lbr_enable		= intel_pmu_lbr_enable,
 	.lbr_disable		= intel_pmu_lbr_disable,
 	.lbr_reset		= intel_pmu_lbr_reset_64,
+	.lbr_read		= intel_pmu_lbr_read_64,
 };
 
 static __init void intel_clovertown_quirk(void)
@@ -4630,8 +4632,10 @@ __init int intel_pmu_init(void)
 		x86_pmu.intel_cap.capabilities = capabilities;
 	}
 
-	if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_32)
+	if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_32) {
 		x86_pmu.lbr_reset = intel_pmu_lbr_reset_32;
+		x86_pmu.lbr_read = intel_pmu_lbr_read_32;
+	}
 
 	intel_ds_init();
 
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index ff320d1..d762c76 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -542,7 +542,7 @@ void intel_pmu_lbr_disable_all(void)
 		x86_pmu.lbr_disable();
 }
 
-static void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)
+void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)
 {
 	unsigned long mask = x86_pmu.lbr_nr - 1;
 	u64 tos = intel_pmu_lbr_tos();
@@ -579,7 +579,7 @@ static void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc)
  * is the same as the linear address, allowing us to merge the LIP and EIP
  * LBR formats.
  */
-static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
+void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
 {
 	bool need_info = false, call_stack = false;
 	unsigned long mask = x86_pmu.lbr_nr - 1;
@@ -683,10 +683,7 @@ void intel_pmu_lbr_read(void)
 	if (!cpuc->lbr_users || cpuc->lbr_users == cpuc->lbr_pebs_users)
 		return;
 
-	if (x86_pmu.intel_cap.lbr_format == LBR_FORMAT_32)
-		intel_pmu_lbr_read_32(cpuc);
-	else
-		intel_pmu_lbr_read_64(cpuc);
+	x86_pmu.lbr_read(cpuc);
 
 	intel_pmu_lbr_filter(cpuc);
 }
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index abf95ef..e2e086c0 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -693,6 +693,7 @@ struct x86_pmu {
 	void		(*lbr_enable)(bool pmi);
 	void		(*lbr_disable)(void);
 	void		(*lbr_reset)(void);
+	void		(*lbr_read)(struct cpu_hw_events *cpuc);
 
 	/*
 	 * Intel PT/LBR/BTS are exclusive
@@ -1086,6 +1087,10 @@ void intel_pmu_lbr_disable(void);
 
 void intel_pmu_lbr_read(void);
 
+void intel_pmu_lbr_read_32(struct cpu_hw_events *cpuc);
+
+void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc);
+
 void intel_pmu_lbr_init_core(void);
 
 void intel_pmu_lbr_init_nhm(void);
-- 
2.7.4