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From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, tamas.zsoldos@arm.com,
	al.grant@arm.com, leo.yan@linaro.org, mike.leach@linaro.org,
	mathieu.poirier@linaro.org, suzuki.poulose@arm.com,
	anshuman.khandual@arm.com, jinlmao@qti.qualcomm.com
Subject: [PATCH v2 10/10] coresight: trbe: Prohibit trace before disabling TRBE
Date: Fri, 23 Jul 2021 13:46:11 +0100	[thread overview]
Message-ID: <20210723124611.3828908-11-suzuki.poulose@arm.com> (raw)
In-Reply-To: <20210723124611.3828908-1-suzuki.poulose@arm.com>

We must prohibit the CPU from tracing before we disable
the TRBE and only re-enable it when we are sure the TRBE
has been enabled back. Otherwise, leave the CPU in
prohibited state.

Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 .../hwtracing/coresight/coresight-self-hosted-trace.h    | 4 +++-
 drivers/hwtracing/coresight/coresight-trbe.c             | 9 +++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-self-hosted-trace.h b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h
index 586d26e0cba3..34372482a3cd 100644
--- a/drivers/hwtracing/coresight/coresight-self-hosted-trace.h
+++ b/drivers/hwtracing/coresight/coresight-self-hosted-trace.h
@@ -22,11 +22,13 @@ static inline void write_trfcr(u64 val)
 	isb();
 }
 
-static inline void cpu_prohibit_trace(void)
+static inline u64 cpu_prohibit_trace(void)
 {
 	u64 trfcr = read_trfcr();
 
 	/* Prohibit tracing at EL0 & the kernel EL */
 	write_trfcr(trfcr & ~(TRFCR_ELx_ExTRE | TRFCR_ELx_E0TRE));
+	/* Return the original value of the TRFCR */
+	return trfcr;
 }
 #endif			/*  __CORESIGHT_SELF_HOSTED_TRACE_H */
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index e7567727e8fc..b8586c170889 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -16,6 +16,7 @@
 #define pr_fmt(fmt) DRVNAME ": " fmt
 
 #include <asm/barrier.h>
+#include "coresight-self-hosted-trace.h"
 #include "coresight-trbe.h"
 
 #define PERF_IDX2OFF(idx, buf) ((idx) % ((buf)->nr_pages << PAGE_SHIFT))
@@ -764,6 +765,7 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
 	enum trbe_fault_action act;
 	u64 status;
 	bool truncated = false;
+	u64 trfcr;
 
 	/* Reads to TRBSR_EL1 is fine when TRBE is active */
 	status = read_sysreg_s(SYS_TRBSR_EL1);
@@ -774,6 +776,8 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
 	if (!is_trbe_irq(status))
 		return IRQ_NONE;
 
+	/* Prohibit the CPU from tracing before we disable the TRBE */
+	trfcr = cpu_prohibit_trace();
 	/*
 	 * Ensure the trace is visible to the CPUs and
 	 * any external aborts have been resolved.
@@ -805,9 +809,14 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
 	/*
 	 * If the buffer was truncated, ensure perf callbacks
 	 * have completed, which will disable the event.
+	 *
+	 * Otherwise, restore the trace filter controls to
+	 * allow the tracing.
 	 */
 	if (truncated)
 		irq_work_run();
+	else
+		write_trfcr(trfcr);
 
 	return IRQ_HANDLED;
 }
-- 
2.24.1


  parent reply	other threads:[~2021-07-23 12:46 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-23 12:46 [PATCH v2 00/10] coresight: TRBE and Self-Hosted trace fixes Suzuki K Poulose
2021-07-23 12:46 ` [PATCH v2 01/10] coresight: etm4x: Save restore TRFCR_EL1 Suzuki K Poulose
2021-07-30  3:05   ` Anshuman Khandual
2021-07-23 12:46 ` [PATCH v2 02/10] coresight: etm4x: Use Trace Filtering controls dynamically Suzuki K Poulose
2021-07-30  3:48   ` Anshuman Khandual
2021-07-30 11:29     ` Suzuki K Poulose
2021-07-23 12:46 ` [PATCH v2 03/10] coresight: etm-pmu: Ensure the AUX handle is valid Suzuki K Poulose
2021-07-30  4:14   ` Anshuman Khandual
2021-07-23 12:46 ` [PATCH v2 04/10] coresight: trbe: Ensure the format flag is set on truncation Suzuki K Poulose
2021-07-30  4:26   ` Anshuman Khandual
2021-07-30 11:37     ` Suzuki K Poulose
2021-07-23 12:46 ` [PATCH v2 05/10] coresight: trbe: Drop duplicate TRUNCATE flags Suzuki K Poulose
2021-07-30  4:47   ` Anshuman Khandual
2021-07-30 12:58     ` Suzuki K Poulose
2021-07-23 12:46 ` [PATCH v2 06/10] coresight: trbe: Fix handling of spurious interrupts Suzuki K Poulose
2021-07-30  5:15   ` Anshuman Khandual
2021-07-30 12:57     ` Suzuki K Poulose
2021-07-23 12:46 ` [PATCH v2 07/10] coresight: trbe: Do not truncate buffer on IRQ Suzuki K Poulose
2021-07-26 12:34   ` Mike Leach
2021-07-26 16:01     ` Suzuki K Poulose
2021-07-27 10:46       ` Mike Leach
2021-07-27 13:06         ` Suzuki K Poulose
2021-07-28  9:25           ` Suzuki K Poulose
2021-07-23 12:46 ` [PATCH v2 08/10] coresight: trbe: Unify the enabling sequence Suzuki K Poulose
2021-07-30  5:40   ` Anshuman Khandual
2021-07-23 12:46 ` [PATCH v2 09/10] coresight: trbe: End the AUX handle on truncation Suzuki K Poulose
2021-07-30  5:54   ` Anshuman Khandual
2021-07-23 12:46 ` Suzuki K Poulose [this message]
2021-07-30  6:58   ` [PATCH v2 10/10] coresight: trbe: Prohibit trace before disabling TRBE Anshuman Khandual
2021-07-23 13:45 ` [PATCH v2 00/10] coresight: TRBE and Self-Hosted trace fixes Suzuki K Poulose

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