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From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: gregkh@linuxfoundation.org
Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 04/31] coresight: etm4x: Skip accessing TRCPDCR in save/restore
Date: Mon,  1 Feb 2021 11:13:24 -0700	[thread overview]
Message-ID: <20210201181351.1475223-5-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20210201181351.1475223-1-mathieu.poirier@linaro.org>

From: Suzuki K Poulose <suzuki.poulose@arm.com>

When the ETM is affected by Qualcomm errata, modifying the
TRCPDCR could cause the system hang. Even though this is
taken care of during enable/disable ETM, the ETM state
save/restore could still access the TRCPDCR. Make sure
we skip the access during the save/restore.

Found by code inspection.

Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Tingwei Zhang <tingwei@codeaurora.org>
Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210110224850.1880240-3-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 4b615e9f3d76..0924c376e35a 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1373,7 +1373,8 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
 
 	state->trcclaimset = readl(drvdata->base + TRCCLAIMCLR);
 
-	state->trcpdcr = readl(drvdata->base + TRCPDCR);
+	if (!drvdata->skip_power_up)
+		state->trcpdcr = readl(drvdata->base + TRCPDCR);
 
 	/* wait for TRCSTATR.IDLE to go up */
 	if (coresight_timeout(drvdata->base, TRCSTATR, TRCSTATR_IDLE_BIT, 1)) {
@@ -1391,9 +1392,9 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
 	 * potentially save power on systems that respect the TRCPDCR_PU
 	 * despite requesting software to save/restore state.
 	 */
-	writel_relaxed((state->trcpdcr & ~TRCPDCR_PU),
-			drvdata->base + TRCPDCR);
-
+	if (!drvdata->skip_power_up)
+		writel_relaxed((state->trcpdcr & ~TRCPDCR_PU),
+				drvdata->base + TRCPDCR);
 out:
 	CS_LOCK(drvdata->base);
 	return ret;
@@ -1488,7 +1489,8 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
 
 	writel_relaxed(state->trcclaimset, drvdata->base + TRCCLAIMSET);
 
-	writel_relaxed(state->trcpdcr, drvdata->base + TRCPDCR);
+	if (!drvdata->skip_power_up)
+		writel_relaxed(state->trcpdcr, drvdata->base + TRCPDCR);
 
 	drvdata->state_needs_restore = false;
 
-- 
2.25.1


WARNING: multiple messages have this Message-ID (diff)
From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: gregkh@linuxfoundation.org
Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH 04/31] coresight: etm4x: Skip accessing TRCPDCR in save/restore
Date: Mon,  1 Feb 2021 11:13:24 -0700	[thread overview]
Message-ID: <20210201181351.1475223-5-mathieu.poirier@linaro.org> (raw)
In-Reply-To: <20210201181351.1475223-1-mathieu.poirier@linaro.org>

From: Suzuki K Poulose <suzuki.poulose@arm.com>

When the ETM is affected by Qualcomm errata, modifying the
TRCPDCR could cause the system hang. Even though this is
taken care of during enable/disable ETM, the ETM state
save/restore could still access the TRCPDCR. Make sure
we skip the access during the save/restore.

Found by code inspection.

Fixes: 02510a5aa78d ("coresight: etm4x: Add support to skip trace unit power up")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Cc: Tingwei Zhang <tingwei@codeaurora.org>
Reviewed-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20210110224850.1880240-3-suzuki.poulose@arm.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 drivers/hwtracing/coresight/coresight-etm4x-core.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 4b615e9f3d76..0924c376e35a 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1373,7 +1373,8 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
 
 	state->trcclaimset = readl(drvdata->base + TRCCLAIMCLR);
 
-	state->trcpdcr = readl(drvdata->base + TRCPDCR);
+	if (!drvdata->skip_power_up)
+		state->trcpdcr = readl(drvdata->base + TRCPDCR);
 
 	/* wait for TRCSTATR.IDLE to go up */
 	if (coresight_timeout(drvdata->base, TRCSTATR, TRCSTATR_IDLE_BIT, 1)) {
@@ -1391,9 +1392,9 @@ static int etm4_cpu_save(struct etmv4_drvdata *drvdata)
 	 * potentially save power on systems that respect the TRCPDCR_PU
 	 * despite requesting software to save/restore state.
 	 */
-	writel_relaxed((state->trcpdcr & ~TRCPDCR_PU),
-			drvdata->base + TRCPDCR);
-
+	if (!drvdata->skip_power_up)
+		writel_relaxed((state->trcpdcr & ~TRCPDCR_PU),
+				drvdata->base + TRCPDCR);
 out:
 	CS_LOCK(drvdata->base);
 	return ret;
@@ -1488,7 +1489,8 @@ static void etm4_cpu_restore(struct etmv4_drvdata *drvdata)
 
 	writel_relaxed(state->trcclaimset, drvdata->base + TRCCLAIMSET);
 
-	writel_relaxed(state->trcpdcr, drvdata->base + TRCPDCR);
+	if (!drvdata->skip_power_up)
+		writel_relaxed(state->trcpdcr, drvdata->base + TRCPDCR);
 
 	drvdata->state_needs_restore = false;
 
-- 
2.25.1


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  parent reply	other threads:[~2021-02-01 18:16 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-01 18:13 [PATCH 00/31] coresight: Patches for v5.12 Mathieu Poirier
2021-02-01 18:13 ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 01/31] coresight: cti: Reduce scope for the variable 'cs_fwnode' in cti_plat_create_connection() Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 02/31] coresight: etm4x: add AMBA id for Cortex-A55 and Cortex-A75 Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 03/31] coresight: etm4x: Handle access to TRCSSPCICRn Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` Mathieu Poirier [this message]
2021-02-01 18:13   ` [PATCH 04/31] coresight: etm4x: Skip accessing TRCPDCR in save/restore Mathieu Poirier
2021-02-01 18:13 ` [PATCH 05/31] coresight: Introduce device access abstraction Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 06/31] coresight: tpiu: Prepare for using coresight " Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 07/31] coresight: Convert coresight_timeout to use " Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 08/31] coresight: Convert claim/disclaim operations to use access wrappers Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 09/31] coresight: etm4x: Always read the registers on the host CPU Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 10/31] coresight: etm4x: Convert all register accesses Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 11/31] coresight: etm4x: Make offset available for sysfs attributes Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 12/31] coresight: etm4x: Add commentary on the registers Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 13/31] coresight: etm4x: Add sysreg access helpers Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 14/31] coresight: etm4x: Hide sysfs attributes for unavailable registers Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 15/31] coresight: etm4x: Define DEVARCH register fields Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 16/31] coresight: etm4x: Check for Software Lock Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 17/31] coresight: etm4x: Cleanup secure exception level masks Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 18/31] coresight: etm4x: Clean up " Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 19/31] coresight: etm4x: Handle ETM architecture version Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 20/31] coresight: etm4x: Detect access early on the target CPU Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 21/31] coresight: etm4x: Use TRCDEVARCH for component discovery Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 22/31] coresight: etm4x: Expose trcdevarch via sysfs Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 23/31] coresight: etm4x: Add necessary synchronization for sysreg access Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 24/31] coresight: etm4x: Detect system instructions support Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 25/31] coresight: etm4x: Refactor probing routine Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 26/31] coresight: etm4x: Run arch feature detection on the CPU Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 27/31] coresight: etm4x: Add support for sysreg only devices Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 28/31] dts: bindings: coresight: ETM system register access only units Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 29/31] arm64: Add TRFCR_ELx definitions Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 30/31] coresight: Add support for v8.4 SelfHosted tracing Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-01 18:13 ` [PATCH 31/31] coresight: etm4x: Handle accesses to TRCSTALLCTLR Mathieu Poirier
2021-02-01 18:13   ` Mathieu Poirier
2021-02-04 16:01 ` [PATCH 00/31] coresight: Patches for v5.12 Greg KH
2021-02-04 16:01   ` Greg KH

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