linux-kernel - [PATCH] perf/x86/intel/pt: Add enables for PTWRITE and power event tracing

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Date:   Fri, 16 Sep 2016 16:48:19 +0300
From:   Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:     Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        vince@...ter.net, eranian@...gle.com,
        Arnaldo Carvalho de Melo <acme@...radead.org>,
        tglx@...utronix.de,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>
Subject: [PATCH] perf/x86/intel/pt: Add enables for PTWRITE and power event tracing

Intel PT chapter in the new Intel Architecture SDM adds several packets
and corresponding enable bits that control packet generation. Also,
additional bits in the Intel PT CPUID leaf were added to enumerate
presence and parameters of these new packets and features.

The packets and enables are:

  * PTWRITE packet carries the payload of the new PTWRITE instruction
    that can be used to instrument Intel PT traces with user-supplied
    data. Packets of this type are only generated if 'ptwrite' capability
    is set and PTWEn bit is set in the event attribute's config. Flow
    update packets (FUP) can be generated on PTWRITE packets if FUPonPTW
    config bit is set. Setting these bits is not allowed if 'ptwrite'
    capability is not set.

  * PWRE, PWRX, MWAIT, EXSTOP packets communicate core power management
    events. These depend on 'power_event_tracing' capability and are
    enabled by setting PwrEvtEn bit in the event attribute.

This patch adds corresponding bit and register definitions, PMU driver
capabilities based on CPUID enumeration, new attribute format bits for
the new featurens and extends event configuration validation function
to take these into account.

Cc: Adrian Hunter <adrian.hunter@...el.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
---
 arch/x86/events/intel/pt.c | 24 +++++++++++++++++++++++-
 arch/x86/events/intel/pt.h |  5 +++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index 861a7d9cb6..c5047b8f77 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -69,6 +69,8 @@ static struct pt_cap_desc {
 	PT_CAP(psb_cyc,			0, CR_EBX, BIT(1)),
 	PT_CAP(ip_filtering,		0, CR_EBX, BIT(2)),
 	PT_CAP(mtc,			0, CR_EBX, BIT(3)),
+	PT_CAP(ptwrite,			0, CR_EBX, BIT(4)),
+	PT_CAP(power_event_trace,	0, CR_EBX, BIT(5)),
 	PT_CAP(topa_output,		0, CR_ECX, BIT(0)),
 	PT_CAP(topa_multiple_entries,	0, CR_ECX, BIT(1)),
 	PT_CAP(single_range_output,	0, CR_ECX, BIT(2)),
@@ -259,10 +261,16 @@ fail:
 #define RTIT_CTL_MTC	(RTIT_CTL_MTC_EN	| \
 			 RTIT_CTL_MTC_RANGE)
 
+#define RTIT_CTL_PTW	(RTIT_CTL_PTW_EN	| \
+			 RTIT_CTL_FUP_ON_PTW)
+
 #define PT_CONFIG_MASK (RTIT_CTL_TSC_EN		| \
 			RTIT_CTL_DISRETC	| \
 			RTIT_CTL_CYC_PSB	| \
-			RTIT_CTL_MTC)
+			RTIT_CTL_MTC		| \
+			RTIT_CTL_PWR_EVT_EN	| \
+			RTIT_CTL_FUP_ON_PTW	| \
+			RTIT_CTL_PTW_EN)
 
 static bool pt_event_valid(struct perf_event *event)
 {
@@ -311,6 +319,20 @@ static bool pt_event_valid(struct perf_event *event)
 			return false;
 	}
 
+	if (config & RTIT_CTL_PWR_EVT_EN &&
+	    !pt_cap_get(PT_CAP_power_event_trace))
+		return false;
+
+	if (config & RTIT_CTL_PTW) {
+		if (!pt_cap_get(PT_CAP_ptwrite))
+			return false;
+
+		/* FUPonPTW without PTW doesn't make sense */
+		if ((config & RTIT_CTL_FUP_ON_PTW) &&
+		    !(config & RTIT_CTL_PTW_EN))
+			return false;
+	}
+
 	return true;
 }
 
diff --git a/arch/x86/events/intel/pt.h b/arch/x86/events/intel/pt.h
index efffa4a09f..53473c21b5 100644
--- a/arch/x86/events/intel/pt.h
+++ b/arch/x86/events/intel/pt.h
@@ -26,11 +26,14 @@
 #define RTIT_CTL_CYCLEACC		BIT(1)
 #define RTIT_CTL_OS			BIT(2)
 #define RTIT_CTL_USR			BIT(3)
+#define RTIT_CTL_PWR_EVT_EN		BIT(4)
+#define RTIT_CTL_FUP_ON_PTW		BIT(5)
 #define RTIT_CTL_CR3EN			BIT(7)
 #define RTIT_CTL_TOPA			BIT(8)
 #define RTIT_CTL_MTC_EN			BIT(9)
 #define RTIT_CTL_TSC_EN			BIT(10)
 #define RTIT_CTL_DISRETC		BIT(11)
+#define RTIT_CTL_PTW_EN			BIT(12)
 #define RTIT_CTL_BRANCH_EN		BIT(13)
 #define RTIT_CTL_MTC_RANGE_OFFSET	14
 #define RTIT_CTL_MTC_RANGE		(0x0full << RTIT_CTL_MTC_RANGE_OFFSET)
@@ -91,6 +94,8 @@ enum pt_capabilities {
 	PT_CAP_psb_cyc,
 	PT_CAP_ip_filtering,
 	PT_CAP_mtc,
+	PT_CAP_ptwrite,
+	PT_CAP_power_event_trace,
 	PT_CAP_topa_output,
 	PT_CAP_topa_multiple_entries,
 	PT_CAP_single_range_output,
-- 
2.9.3