From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: mathieu.poirier@linaro.org, linux-arm-kernel@lists.infradead.org
Cc: anshuman.khandual@arm.com, mike.leach@linaro.org,
leo.yan@linaro.org, coresight@lists.linaro.org,
linux-kernel@vger.kernel.org,
Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH v4 1/5] coresight: trbe: irq handler: Do not disable TRBE if no action is needed
Date: Thu, 23 Sep 2021 15:39:15 +0100 [thread overview]
Message-ID: <20210923143919.2944311-2-suzuki.poulose@arm.com> (raw)
In-Reply-To: <20210923143919.2944311-1-suzuki.poulose@arm.com>
The IRQ handler of the TRBE driver could race against the update_buffer()
in consuming the IRQ. So, if the update_buffer() gets to processing the
TRBE irq, the TRBSR will be cleared. Thus by the time IRQ handler is
triggered, there is nothing to do there. Handle these cases and do not
disable the TRBE unnecessarily. Since the TRBSR can be read without
stopping the TRBE, we can check that before disabling the TRBE.
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
drivers/hwtracing/coresight/coresight-trbe.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 2cf28de2e447..e78800ba5b5b 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -762,12 +762,7 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
enum trbe_fault_action act;
u64 status;
- /*
- * Ensure the trace is visible to the CPUs and
- * any external aborts have been resolved.
- */
- trbe_drain_and_disable_local();
-
+ /* Reads to TRBSR_EL1 is fine when TRBE is active */
status = read_sysreg_s(SYS_TRBSR_EL1);
/*
* If the pending IRQ was handled by update_buffer callback
@@ -776,6 +771,11 @@ static irqreturn_t arm_trbe_irq_handler(int irq, void *dev)
if (!is_trbe_irq(status))
return IRQ_NONE;
+ /*
+ * Ensure the trace is visible to the CPUs and
+ * any external aborts have been resolved.
+ */
+ trbe_drain_and_disable_local();
clr_trbe_irq();
isb();
--
2.24.1
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next prev parent reply other threads:[~2021-09-23 14:42 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 14:39 [PATCH v4 0/5] coresight: TRBE and Self-Hosted trace fixes Suzuki K Poulose
2021-09-23 14:39 ` Suzuki K Poulose [this message]
2021-09-23 14:39 ` [PATCH v4 2/5] coresight: trbe: Fix handling of spurious interrupts Suzuki K Poulose
2021-09-23 14:39 ` [PATCH v4 3/5] coresight: trbe: Do not truncate buffer on IRQ Suzuki K Poulose
2021-09-23 14:39 ` [PATCH v4 4/5] coresight: trbe: End the AUX handle on truncation Suzuki K Poulose
2021-09-23 14:39 ` [PATCH v4 5/5] coresight: trbe: Prohibit trace before disabling TRBE Suzuki K Poulose
2021-09-23 16:55 ` [PATCH v4 0/5] coresight: TRBE and Self-Hosted trace fixes Mathieu Poirier
2021-09-23 18:07 ` Suzuki K Poulose
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