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From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, coresight@lists.linaro.org,
	anshuman.khandual@arm.com, will@kernel.org,
	catalin.marinas@arm.com, james.morse@arm.com,
	mathieu.poirier@linaro.org, mike.leach@linaro.org,
	leo.yan@linaro.org, maz@kernel.org, mark.rutland@arm.com,
	Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH 02/10] coresight: trbe: Add a helper to calculate the trace generated
Date: Wed, 28 Jul 2021 14:52:09 +0100	[thread overview]
Message-ID: <20210728135217.591173-3-suzuki.poulose@arm.com> (raw)
In-Reply-To: <20210728135217.591173-1-suzuki.poulose@arm.com>

We collect the trace from the TRBE on FILL event from IRQ context
and when via update_buffer(), when the event is stopped. Let us
consolidate how we calculate the trace generated into a helper.

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-trbe.c | 48 ++++++++++++--------
 1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index 0368bf405e35..a0168ad204b3 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c
@@ -528,6 +528,30 @@ static enum trbe_fault_action trbe_get_fault_act(u64 trbsr)
 	return TRBE_FAULT_ACT_SPURIOUS;
 }
 
+static unsigned long trbe_get_trace_size(struct perf_output_handle *handle,
+					 struct trbe_buf *buf,
+					 bool wrap)
+{
+	u64 write;
+	u64 start_off, end_off;
+
+	/*
+	 * If the TRBE has wrapped around the write pointer has
+	 * wrapped and should be treated as limit.
+	 */
+	if (wrap)
+		write = get_trbe_limit_pointer();
+	else
+		write = get_trbe_write_pointer();
+
+	end_off = write - buf->trbe_base;
+	start_off = PERF_IDX2OFF(handle->head, buf);
+
+	if (WARN_ON_ONCE(end_off < start_off))
+		return 0;
+	return (end_off - start_off);
+}
+
 static void *arm_trbe_alloc_buffer(struct coresight_device *csdev,
 				   struct perf_event *event, void **pages,
 				   int nr_pages, bool snapshot)
@@ -589,9 +613,9 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev,
 	struct trbe_cpudata *cpudata = dev_get_drvdata(&csdev->dev);
 	struct trbe_buf *buf = config;
 	enum trbe_fault_action act;
-	unsigned long size, offset;
-	unsigned long write, base, status;
+	unsigned long size, status;
 	unsigned long flags;
+	bool wrap = false;
 
 	WARN_ON(buf->cpudata != cpudata);
 	WARN_ON(cpudata->cpu != smp_processor_id());
@@ -633,8 +657,6 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev,
 	 * handle gets freed in etm_event_stop().
 	 */
 	trbe_drain_and_disable_local();
-	write = get_trbe_write_pointer();
-	base = get_trbe_base_pointer();
 
 	/* Check if there is a pending interrupt and handle it here */
 	status = read_sysreg_s(SYS_TRBSR_EL1);
@@ -658,20 +680,11 @@ static unsigned long arm_trbe_update_buffer(struct coresight_device *csdev,
 			goto done;
 		}
 
-		/*
-		 * Otherwise, the buffer is full and the write pointer
-		 * has reached base. Adjust this back to the Limit pointer
-		 * for correct size. Also, mark the buffer truncated.
-		 */
-		write = get_trbe_limit_pointer();
 		perf_aux_output_flag(handle, PERF_AUX_FLAG_COLLISION);
+		wrap = true;
 	}
 
-	offset = write - base;
-	if (WARN_ON_ONCE(offset < PERF_IDX2OFF(handle->head, buf)))
-		size = 0;
-	else
-		size = offset - PERF_IDX2OFF(handle->head, buf);
+	size = trbe_get_trace_size(handle, buf, wrap);
 
 done:
 	local_irq_restore(flags);
@@ -752,11 +765,10 @@ static int trbe_handle_overflow(struct perf_output_handle *handle)
 {
 	struct perf_event *event = handle->event;
 	struct trbe_buf *buf = etm_perf_sink_config(handle);
-	unsigned long offset, size;
+	unsigned long size;
 	struct etm_event_data *event_data;
 
-	offset = get_trbe_limit_pointer() - get_trbe_base_pointer();
-	size = offset - PERF_IDX2OFF(handle->head, buf);
+	size = trbe_get_trace_size(handle, buf, true);
 	if (buf->snapshot)
 		handle->head += size;
 
-- 
2.24.1


  parent reply	other threads:[~2021-07-28 13:54 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-28 13:52 [PATCH 00/10] arm64: Self-hosted trace related erratum workarouds Suzuki K Poulose
2021-07-28 13:52 ` [PATCH 01/10] coresight: trbe: Add infrastructure for Errata handling Suzuki K Poulose
2021-08-02  6:43   ` Anshuman Khandual
2021-09-07  9:04     ` Suzuki K Poulose
2021-09-09  2:55       ` Anshuman Khandual
2021-07-28 13:52 ` Suzuki K Poulose [this message]
2021-07-30 10:01   ` [PATCH 02/10] coresight: trbe: Add a helper to calculate the trace generated Anshuman Khandual
2021-07-28 13:52 ` [PATCH 03/10] coresight: trbe: Add a helper to pad a given buffer area Suzuki K Poulose
2021-07-30 10:05   ` Anshuman Khandual
2021-07-28 13:52 ` [PATCH 04/10] coresight: trbe: Decouple buffer base from the hardware base Suzuki K Poulose
2021-07-30 10:53   ` Anshuman Khandual
2021-07-28 13:52 ` [PATCH 05/10] coresight: trbe: Allow driver to choose a different alignment Suzuki K Poulose
2021-07-30 11:02   ` Anshuman Khandual
2021-07-30 14:29     ` Suzuki K Poulose
2021-07-28 13:52 ` [PATCH 06/10] arm64: Add Neoverse-N2, Cortex-A710 CPU part definition Suzuki K Poulose
2021-07-30 11:26   ` Anshuman Khandual
2021-07-30 14:31     ` Suzuki K Poulose
2021-08-02 11:21   ` Catalin Marinas
2021-08-02 11:21   ` Catalin Marinas
2021-07-28 13:52 ` [PATCH 07/10] arm64: Add erratum detection for TRBE overwrite in FILL mode Suzuki K Poulose
2021-08-02  7:44   ` Anshuman Khandual
2021-08-02 11:22   ` Catalin Marinas
2021-08-06 12:44   ` Linu Cherian
2021-09-07  9:10     ` Suzuki K Poulose
2021-07-28 13:52 ` [PATCH 08/10] coresight: trbe: Workaround TRBE errat " Suzuki K Poulose
2021-08-03 10:25   ` Anshuman Khandual
2021-09-07  9:58     ` Suzuki K Poulose
2021-09-09  4:21       ` Anshuman Khandual
2021-09-09  8:37         ` Suzuki K Poulose
2021-08-06 16:09   ` Linu Cherian
2021-09-07  9:18     ` Suzuki K Poulose
2021-07-28 13:52 ` [PATCH 09/10] arm64: Enable workaround for TRBE " Suzuki K Poulose
2021-08-02  9:34   ` Anshuman Khandual
2021-08-02 11:24   ` Catalin Marinas
2021-07-28 13:52 ` [PATCH 10/10] arm64: errata: Add workaround for TSB flush failures Suzuki K Poulose
2021-07-29  9:55   ` Marc Zyngier
2021-07-29 10:41     ` Suzuki K Poulose
2021-08-02  9:12       ` Anshuman Khandual
2021-08-02  9:35         ` Marc Zyngier
2021-08-03  3:51           ` Anshuman Khandual
2021-09-08 13:39             ` Suzuki K Poulose
2021-08-02 11:27   ` Catalin Marinas

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