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From: Yabin Cui <yabinc@google.com>
To: Mathieu Poirier <mathieu.poirier@linaro.org>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mike Leach <mike.leach@linaro.org>, Leo Yan <leo.yan@linaro.org>,
	James Clark <james.clark@arm.com>
Cc: coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, Yabin Cui <yabinc@google.com>
Subject: [PATCH v3] coresight: tmc: Don't enable TMC when it's not ready.
Date: Thu,  2 Feb 2023 21:46:32 +0000	[thread overview]
Message-ID: <20230202214633.12584-1-yabinc@google.com> (raw)
In-Reply-To: <CALJ9ZPNrF-HhUNskr=_MJ1CrnO+0xzSN8pMpER3FMqf5Pd0idg@mail.gmail.com>

If TMC ETR is enabled without being ready, in later use we may
see AXI bus errors caused by accessing invalid addresses.

Signed-off-by: Yabin Cui <yabinc@google.com>
---
V1 -> V2: Make change to all TMCs instead of just ETR
V2 -> V3: Handle etr enable failure in tmc_read_unprepare_etr

 .../hwtracing/coresight/coresight-tmc-core.c  |  4 +-
 .../hwtracing/coresight/coresight-tmc-etf.c   | 43 +++++++++++++++----
 .../hwtracing/coresight/coresight-tmc-etr.c   | 25 +++++++++--
 drivers/hwtracing/coresight/coresight-tmc.h   |  2 +-
 4 files changed, 59 insertions(+), 15 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index 07abf28ad725..c106d142e632 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -31,7 +31,7 @@ DEFINE_CORESIGHT_DEVLIST(etb_devs, "tmc_etb");
 DEFINE_CORESIGHT_DEVLIST(etf_devs, "tmc_etf");
 DEFINE_CORESIGHT_DEVLIST(etr_devs, "tmc_etr");
 
-void tmc_wait_for_tmcready(struct tmc_drvdata *drvdata)
+int tmc_wait_for_tmcready(struct tmc_drvdata *drvdata)
 {
 	struct coresight_device *csdev = drvdata->csdev;
 	struct csdev_access *csa = &csdev->access;
@@ -40,7 +40,9 @@ void tmc_wait_for_tmcready(struct tmc_drvdata *drvdata)
 	if (coresight_timeout(csa, TMC_STS, TMC_STS_TMCREADY_BIT, 1)) {
 		dev_err(&csdev->dev,
 			"timeout while waiting for TMC to be Ready\n");
+		return -EBUSY;
 	}
+	return 0;
 }
 
 void tmc_flush_and_stop(struct tmc_drvdata *drvdata)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 4c4cbd1f7258..2840227e9135 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -16,12 +16,19 @@
 static int tmc_set_etf_buffer(struct coresight_device *csdev,
 			      struct perf_output_handle *handle);
 
-static void __tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
+static int __tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
 {
+	int rc = 0;
+
 	CS_UNLOCK(drvdata->base);
 
 	/* Wait for TMCSReady bit to be set */
-	tmc_wait_for_tmcready(drvdata);
+	rc = tmc_wait_for_tmcready(drvdata);
+	if (rc) {
+		dev_err(&drvdata->csdev->dev, "fails to enable not ready TMC\n");
+		CS_LOCK(drvdata->base);
+		return rc;
+	}
 
 	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);
 	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI |
@@ -33,6 +40,7 @@ static void __tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
 	tmc_enable_hw(drvdata);
 
 	CS_LOCK(drvdata->base);
+	return rc;
 }
 
 static int tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
@@ -42,8 +50,10 @@ static int tmc_etb_enable_hw(struct tmc_drvdata *drvdata)
 	if (rc)
 		return rc;
 
-	__tmc_etb_enable_hw(drvdata);
-	return 0;
+	rc = __tmc_etb_enable_hw(drvdata);
+	if (rc)
+		coresight_disclaim_device(drvdata->csdev);
+	return rc;
 }
 
 static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
@@ -91,12 +101,19 @@ static void tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
 	coresight_disclaim_device(drvdata->csdev);
 }
 
-static void __tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
+static int __tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
 {
+	int rc = 0;
+
 	CS_UNLOCK(drvdata->base);
 
 	/* Wait for TMCSReady bit to be set */
-	tmc_wait_for_tmcready(drvdata);
+	rc = tmc_wait_for_tmcready(drvdata);
+	if (rc) {
+		dev_err(&drvdata->csdev->dev, "fails to enable not ready TMC\n");
+		CS_LOCK(drvdata->base);
+		return rc;
+	}
 
 	writel_relaxed(TMC_MODE_HARDWARE_FIFO, drvdata->base + TMC_MODE);
 	writel_relaxed(TMC_FFCR_EN_FMT | TMC_FFCR_EN_TI,
@@ -105,6 +122,7 @@ static void __tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
 	tmc_enable_hw(drvdata);
 
 	CS_LOCK(drvdata->base);
+	return rc;
 }
 
 static int tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
@@ -114,8 +132,10 @@ static int tmc_etf_enable_hw(struct tmc_drvdata *drvdata)
 	if (rc)
 		return rc;
 
-	__tmc_etf_enable_hw(drvdata);
-	return 0;
+	rc = __tmc_etf_enable_hw(drvdata);
+	if (rc)
+		coresight_disclaim_device(drvdata->csdev);
+	return rc;
 }
 
 static void tmc_etf_disable_hw(struct tmc_drvdata *drvdata)
@@ -639,6 +659,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 	char *buf = NULL;
 	enum tmc_mode mode;
 	unsigned long flags;
+	int rc = 0;
 
 	/* config types are set a boot time and never change */
 	if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB &&
@@ -664,7 +685,11 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
 		 * can't be NULL.
 		 */
 		memset(drvdata->buf, 0, drvdata->size);
-		__tmc_etb_enable_hw(drvdata);
+		rc = __tmc_etb_enable_hw(drvdata);
+		if (rc) {
+			spin_unlock_irqrestore(&drvdata->spinlock, flags);
+			return rc;
+		}
 	} else {
 		/*
 		 * The ETB/ETF is not tracing and the buffer was just read.
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 867ad8bb9b0c..4952425dd6e4 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -983,15 +983,21 @@ static void tmc_sync_etr_buf(struct tmc_drvdata *drvdata)
 	etr_buf->ops->sync(etr_buf, rrp, rwp);
 }
 
-static void __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
+static int __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
 {
 	u32 axictl, sts;
 	struct etr_buf *etr_buf = drvdata->etr_buf;
+	int rc = 0;
 
 	CS_UNLOCK(drvdata->base);
 
 	/* Wait for TMCSReady bit to be set */
-	tmc_wait_for_tmcready(drvdata);
+	rc = tmc_wait_for_tmcready(drvdata);
+	if (rc) {
+		dev_err(&drvdata->csdev->dev, "fails to enable not ready TMC\n");
+		CS_LOCK(drvdata->base);
+		return rc;
+	}
 
 	writel_relaxed(etr_buf->size / 4, drvdata->base + TMC_RSZ);
 	writel_relaxed(TMC_MODE_CIRCULAR_BUFFER, drvdata->base + TMC_MODE);
@@ -1032,6 +1038,7 @@ static void __tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
 	tmc_enable_hw(drvdata);
 
 	CS_LOCK(drvdata->base);
+	return rc;
 }
 
 static int tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
@@ -1060,7 +1067,12 @@ static int tmc_etr_enable_hw(struct tmc_drvdata *drvdata,
 	rc = coresight_claim_device(drvdata->csdev);
 	if (!rc) {
 		drvdata->etr_buf = etr_buf;
-		__tmc_etr_enable_hw(drvdata);
+		rc = __tmc_etr_enable_hw(drvdata);
+		if (rc) {
+			drvdata->etr_buf = NULL;
+			coresight_disclaim_device(drvdata->csdev);
+			tmc_etr_disable_catu(drvdata);
+		}
 	}
 
 	return rc;
@@ -1750,6 +1762,7 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
 {
 	unsigned long flags;
 	struct etr_buf *sysfs_buf = NULL;
+	int rc = 0;
 
 	/* config types are set a boot time and never change */
 	if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETR))
@@ -1764,7 +1777,11 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
 		 * buffer. Since the tracer is still enabled drvdata::buf can't
 		 * be NULL.
 		 */
-		__tmc_etr_enable_hw(drvdata);
+		rc = __tmc_etr_enable_hw(drvdata);
+		if (rc) {
+			spin_unlock_irqrestore(&drvdata->spinlock, flags);
+			return rc;
+		}
 	} else {
 		/*
 		 * The ETR is not tracing and the buffer was just read.
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 66959557cf39..01c0382a29c0 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -255,7 +255,7 @@ struct tmc_sg_table {
 };
 
 /* Generic functions */
-void tmc_wait_for_tmcready(struct tmc_drvdata *drvdata);
+int tmc_wait_for_tmcready(struct tmc_drvdata *drvdata);
 void tmc_flush_and_stop(struct tmc_drvdata *drvdata);
 void tmc_enable_hw(struct tmc_drvdata *drvdata);
 void tmc_disable_hw(struct tmc_drvdata *drvdata);
-- 
2.39.1.519.gcb327c4b5f-goog


  reply	other threads:[~2023-02-02 21:46 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-09 23:43 [PATCH] coresight: tmc-etr: Don't enable ETR " Yabin Cui
2023-01-10  9:30 ` James Clark
2023-01-10 17:48   ` Mike Leach
2023-01-10 18:04     ` Suzuki K Poulose
2023-01-10 21:06       ` Yabin Cui
2023-01-24 20:09         ` Yabin Cui
2023-01-25 10:21           ` James Clark
2023-01-25 10:27           ` Suzuki K Poulose
2023-01-27 23:10             ` [PATCH v2] coresight: tmc: Don't enable TMC " Yabin Cui
2023-02-01 20:43               ` Mike Leach
2023-02-02 11:24                 ` Suzuki K Poulose
2023-02-02 20:54                   ` Yabin Cui
2023-02-02 21:46                     ` Yabin Cui [this message]
2023-02-09  1:08                       ` [PATCH v3] " Yabin Cui
2023-02-09 10:31                         ` Suzuki K Poulose
2023-02-10 23:43                           ` [PATCH] coresight: tmc-etr: Handle enable failure in tmc_read_unprepare_etr Yabin Cui
2023-02-21 18:38                             ` Yabin Cui
2023-02-22  9:33                               ` Suzuki K Poulose

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