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[PATCH v2 0/9] coresight: Miscellaneous fixes

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  [PATCH v2 0/9] coresight: Miscellaneous fixes Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH v2 1/9] coresight: Fix NULL pointer dereference in _coresight_build_path Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH v2 6/9] coresight: etmv4: Fix ETMv4x peripheral ID table Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH v2 5/9] coresight: tmc: Limit the trace to available data Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH v2 3/9] coresight: Remove erroneous dma_free_coherent in tmc_probe Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH v2 8/9] coresight: Consolidate error handling path for tmc_probe Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH v2 7/9] coresight: Cleanup TMC status check Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH v2 4/9] coresight: Fix csdev connections initialisation Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH v2 2/9] coresight: Fix tmc_read_unprepare_etr Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-06 11:20 +0200
    [PATCH] coresight: Fix erroneous memset in tmc_read_unprepare_etr Suzuki K Poulose <suzuki.poulose@arm.com> - 2016-06-10 12:40 +0200

#1414808 — [PATCH v2 0/9] coresight: Miscellaneous fixes

This is a collection fixes / cleanups for the coresight driver.

Patches 1-5 are fixes, and the remaining patches are clean ups.

Changes since V2:
 - Added a patch to limit the trace data
 - Added a patch to fix tmc_read_unprepare_etr (another crash)
 - Split the patch to remove erraneous dma_free_coherent.
 - Use consistent error message format for coresight_timeout cleanup.
 - Fixed checkpatch warnings on the commit description, there are
   some errors reported on the "crash output" in the commit description.
   May be the checkpatch needs to be fixed ?

Suzuki K Poulose (9):
  coresight: Fix NULL pointer dereference in _coresight_build_path
  coresight: Fix tmc_read_unprepare_etr
  coresight: Remove erroneous dma_free_coherent in tmc_probe
  coresight: Fix csdev connections initialisation
  coresight: tmc: Limit the trace to available data
  coresight: etmv4: Fix ETMv4x peripheral ID table
  coresight: Cleanup TMC status check
  coresight: Consolidate error handling path for tmc_probe
  coresight: Add better messages for coresight_timeout

 drivers/hwtracing/coresight/coresight-etb10.c   |  7 ++--
 drivers/hwtracing/coresight/coresight-etm4x.c   | 14 +++----
 drivers/hwtracing/coresight/coresight-tmc-etf.c |  2 +
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 14 +++++--
 drivers/hwtracing/coresight/coresight-tmc.c     | 52 +++++++++++--------------
 drivers/hwtracing/coresight/coresight-tmc.h     |  4 +-
 drivers/hwtracing/coresight/coresight.c         | 30 +++++++-------
 7 files changed, 64 insertions(+), 59 deletions(-)

-- 
1.9.1

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#1414809 — [PATCH v2 1/9] coresight: Fix NULL pointer dereference in _coresight_build_path

_coresight_build_path assumes that all the connections of a csdev
has the child_dev initialised. This may not be true if the particular
component is not supported by the kernel config(e.g TPIU) but is
present in the DT. In which case, building a path can cause a crash like
this :

  Unable to handle kernel NULL pointer dereference at virtual
  address 00000010
  pgd = ffffffc9750dd000
  [00000010] *pgd=00000009f5e90003, *pud=00000009f5e90003,
  *pmd=0000000000000000
  Internal error: Oops: 96000006 [#1] PREEMPT SMP
  Modules linked in:
  CPU: 4 PID: 1348 Comm: bash Not tainted 4.6.0-next-20160517 #1646
  Hardware name: ARM Juno development board (r0) (DT)
  task: ffffffc97517a280 ti: ffffffc9762c4000 task.ti: ffffffc9762c4000
  PC is at _coresight_build_path+0x18/0xe4
  LR is at _coresight_build_path+0xc0/0xe4
  pc : [<ffffff80083d5130>] lr : [<ffffff80083d51d8>] pstate: 20000145
  sp : ffffffc9762c7ba0

  [<ffffff80083d5130>] _coresight_build_path+0x18/0xe4
  [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4
  [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4
  [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4
  [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4
  [<ffffff80083d51d8>] _coresight_build_path+0xc0/0xe4
  [<ffffff80083d5cdc>] coresight_build_path+0x40/0x68
  [<ffffff80083d5e14>] coresight_enable+0x74/0x1bc
  [<ffffff80083d60a0>] enable_source_store+0x3c/0x6c
  [<ffffff800830b17c>] dev_attr_store+0x18/0x28
  [<ffffff80081ca9c4>] sysfs_kf_write+0x40/0x50
  [<ffffff80081c9e38>] kernfs_fop_write+0x140/0x1cc
  [<ffffff8008163ec8>] __vfs_write+0x28/0x110
  [<ffffff8008164bf0>] vfs_write+0xa0/0x174
  [<ffffff8008165d18>] SyS_write+0x44/0xa0
  [<ffffff8008084e70>] el0_svc_naked+0x24/0x28

Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 5443d03..0fdaaf4 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -385,7 +385,6 @@ static int _coresight_build_path(struct coresight_device *csdev,
 	int i;
 	bool found = false;
 	struct coresight_node *node;
-	struct coresight_connection *conn;
 
 	/* An activated sink has been found.  Enqueue the element */
 	if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
@@ -394,8 +393,9 @@ static int _coresight_build_path(struct coresight_device *csdev,
 
 	/* Not a sink - recursively explore each port found on this element */
 	for (i = 0; i < csdev->nr_outport; i++) {
-		conn = &csdev->conns[i];
-		if (_coresight_build_path(conn->child_dev, path) == 0) {
+		struct coresight_device *child_dev = csdev->conns[i].child_dev;
+
+		if (child_dev && _coresight_build_path(child_dev, path) == 0) {
 			found = true;
 			break;
 		}
-- 
1.9.1

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#1414810 — [PATCH v2 6/9] coresight: etmv4: Fix ETMv4x peripheral ID table

This patch cleans up the peripheral id table for different ETMv4
implementations.

As per Cortex-A53 TRM, the ETM has following id values:

Peripheral ID0	0x5D	0xFE0
Peripheral ID1	0xB9	0xFE4
Peripheral ID2	0x4B	0xFE8
Peripheral ID3	0x00	0xFEC

where, PID2: has the following format:

[7:4]   Revision
[3]     JEDEC   0b1     res1. Indicates a JEP106 identity code is used
[2:0]   DES_1   0b011   ARM Limited. This is bits[6:4] of JEP106 ID code

The existing table entry checks only the bits [1:0], which is not
sufficient enough. Fix it to match bits [3:0], just like the other
entries do. While at it, correct the comment for A57 and the A53 entry.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-etm4x.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 462f0dc..88947f3 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -815,12 +815,12 @@ err_arch_supported:
 }
 
 static struct amba_id etm4_ids[] = {
-	{       /* ETM 4.0 - Qualcomm */
-		.id	= 0x0003b95d,
-		.mask	= 0x0003ffff,
+	{       /* ETM 4.0 - Cortex-A53  */
+		.id	= 0x000bb95d,
+		.mask	= 0x000fffff,
 		.data	= "ETM 4.0",
 	},
-	{       /* ETM 4.0 - Juno board */
+	{       /* ETM 4.0 - Cortex-A57 */
 		.id	= 0x000bb95e,
 		.mask	= 0x000fffff,
 		.data	= "ETM 4.0",
-- 
1.9.1

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#1414811 — [PATCH v2 5/9] coresight: tmc: Limit the trace to available data

At present the ETF or ETR gives out the entire device
buffer, even if there is less or even no trace data
available. This patch limits the trace data given out to
the actual trace data collected.

Cc: mathieu.poirier@linaro.org
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etf.c |  2 ++
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 12 +++++++++---
 drivers/hwtracing/coresight/coresight-tmc.c     |  6 +++---
 drivers/hwtracing/coresight/coresight-tmc.h     |  4 +++-
 4 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 466af86..e68289b 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -48,6 +48,7 @@ static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
 	int i;
 
 	bufp = drvdata->buf;
+	drvdata->len = 0;
 	while (1) {
 		for (i = 0; i < drvdata->memwidth; i++) {
 			read_data = readl_relaxed(drvdata->base + TMC_RRD);
@@ -55,6 +56,7 @@ static void tmc_etb_dump_hw(struct tmc_drvdata *drvdata)
 				return;
 			memcpy(bufp, &read_data, 4);
 			bufp += 4;
+			drvdata->len += 4;
 		}
 	}
 }
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 3369d7a..cdb29c9 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -64,11 +64,17 @@ static void tmc_etr_dump_hw(struct tmc_drvdata *drvdata)
 	rwp = readl_relaxed(drvdata->base + TMC_RWP);
 	val = readl_relaxed(drvdata->base + TMC_STS);
 
-	/* How much memory do we still have */
-	if (val & BIT(0))
+	/*
+	 * Adjust the buffer to point to the beginning of the trace data
+	 * and the available trace data.
+	 */
+	if (val & BIT(0)) {
 		drvdata->buf = drvdata->vaddr + rwp - drvdata->paddr;
-	else
+		drvdata->len = drvdata->size;
+	} else {
 		drvdata->buf = drvdata->vaddr;
+		drvdata->len = rwp - drvdata->paddr;
+	}
 }
 
 static void tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 3978cbb..1b1651d 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -140,8 +140,8 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
 						   struct tmc_drvdata, miscdev);
 	char *bufp = drvdata->buf + *ppos;
 
-	if (*ppos + len > drvdata->size)
-		len = drvdata->size - *ppos;
+	if (*ppos + len > drvdata->len)
+		len = drvdata->len - *ppos;
 
 	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR) {
 		if (bufp == (char *)(drvdata->vaddr + drvdata->size))
@@ -160,7 +160,7 @@ static ssize_t tmc_read(struct file *file, char __user *data, size_t len,
 	*ppos += len;
 
 	dev_dbg(drvdata->dev, "%s: %zu bytes copied, %d bytes left\n",
-		__func__, len, (int)(drvdata->size - *ppos));
+		__func__, len, (int)(drvdata->len - *ppos));
 	return len;
 }
 
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 5c5fe2a..44b3ae3 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -98,7 +98,8 @@ enum tmc_mem_intf_width {
  * @buf:	area of memory where trace data get sent.
  * @paddr:	DMA start location in RAM.
  * @vaddr:	virtual representation of @paddr.
- * @size:	@buf size.
+ * @size:	trace buffer size.
+ * @len:	size of the available trace.
  * @mode:	how this TMC is being used.
  * @config_type: TMC variant, must be of type @tmc_config_type.
  * @memwidth:	width of the memory interface databus, in bytes.
@@ -115,6 +116,7 @@ struct tmc_drvdata {
 	dma_addr_t		paddr;
 	void __iomem		*vaddr;
 	u32			size;
+	u32			len;
 	local_t			mode;
 	enum tmc_config_type	config_type;
 	enum tmc_mem_intf_width	memwidth;
-- 
1.9.1

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#1414812 — [PATCH v2 3/9] coresight: Remove erroneous dma_free_coherent in tmc_probe

commit de5461970b3e9e194 ("coresight: tmc: allocating memory when needed")
removed the static allocation of buffer for the trace data in ETR mode in
tmc_probe. However it failed to remove the "devm_free_coherent" in
tmc_probe when the probe fails due to other reasons. This patch gets
rid of the incorrect dma_free_coherent() call. Also consolidates the
error return paths.

Fixes: commit de5461970b3e9e194 ("coresight: tmc: allocating memory when needed")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 9e02ac9..3978cbb 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -388,9 +388,6 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 err_misc_register:
 	coresight_unregister(drvdata->csdev);
 err_devm_kzalloc:
-	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
-		dma_free_coherent(dev, drvdata->size,
-				drvdata->vaddr, drvdata->paddr);
 	return ret;
 }
 
-- 
1.9.1

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#1414814 — [PATCH v2 8/9] coresight: Consolidate error handling path for tmc_probe

This patch cleans up the error handling path for tmc_probe
as a side effect of the removal of the spurious dma_free_coherent().

Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc.c | 36 ++++++++++++++---------------
 1 file changed, 17 insertions(+), 19 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
index 1b1651d..b3275bb 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.c
+++ b/drivers/hwtracing/coresight/coresight-tmc.c
@@ -309,22 +309,31 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 
 	if (np) {
 		pdata = of_get_coresight_platform_data(dev, np);
-		if (IS_ERR(pdata))
-			return PTR_ERR(pdata);
+		if (IS_ERR(pdata)) {
+			ret = PTR_ERR(pdata);
+			goto out;
+		}
 		adev->dev.platform_data = pdata;
 	}
 
+	ret = -ENOMEM;
 	drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
 	if (!drvdata)
-		return -ENOMEM;
+		goto out;
+
+	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		goto out;
 
 	drvdata->dev = &adev->dev;
 	dev_set_drvdata(dev, drvdata);
 
 	/* Validity for the resource is already checked by the AMBA core */
 	base = devm_ioremap_resource(dev, res);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	if (IS_ERR(base)) {
+		ret = PTR_ERR(base);
+		goto out;
+	}
 
 	drvdata->base = base;
 
@@ -347,12 +356,6 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 
 	pm_runtime_put(&adev->dev);
 
-	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
-	if (!desc) {
-		ret = -ENOMEM;
-		goto err_devm_kzalloc;
-	}
-
 	desc->pdata = pdata;
 	desc->dev = dev;
 	desc->subtype.sink_subtype = CORESIGHT_DEV_SUBTYPE_SINK_BUFFER;
@@ -373,7 +376,7 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 	drvdata->csdev = coresight_register(desc);
 	if (IS_ERR(drvdata->csdev)) {
 		ret = PTR_ERR(drvdata->csdev);
-		goto err_devm_kzalloc;
+		goto out;
 	}
 
 	drvdata->miscdev.name = pdata->name;
@@ -381,13 +384,8 @@ static int tmc_probe(struct amba_device *adev, const struct amba_id *id)
 	drvdata->miscdev.fops = &tmc_fops;
 	ret = misc_register(&drvdata->miscdev);
 	if (ret)
-		goto err_misc_register;
-
-	return 0;
-
-err_misc_register:
-	coresight_unregister(drvdata->csdev);
-err_devm_kzalloc:
+		coresight_unregister(drvdata->csdev);
+out:
 	return ret;
 }
 
-- 
1.9.1

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#1414815 — [PATCH v2 7/9] coresight: Cleanup TMC status check

Use the defined symbol rather than hardcoding the value to
check whether the TMC buffer is full.

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index cdb29c9..69e104b 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -68,7 +68,7 @@ static void tmc_etr_dump_hw(struct tmc_drvdata *drvdata)
 	 * Adjust the buffer to point to the beginning of the trace data
 	 * and the available trace data.
 	 */
-	if (val & BIT(0)) {
+	if (val & TMC_STS_FULL) {
 		drvdata->buf = drvdata->vaddr + rwp - drvdata->paddr;
 		drvdata->len = drvdata->size;
 	} else {
-- 
1.9.1

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#1414816 — [PATCH v2 4/9] coresight: Fix csdev connections initialisation

This is a cleanup patch.

coresight_device->conns holds an array to point to the devices
connected to the OUT ports of a component. Sinks, e.g ETR, do not
have an OUT port (nr_outport = 0), as it streams the trace to
memory via AXI.

At coresight_register() we do :

	conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
	if (!conns) {
		ret = -ENOMEM;
		goto err_kzalloc_conns;
	}

For ETR, since the total size requested for kcalloc is zero, the return
value is, ZERO_SIZE_PTR ( != NULL). Hence, csdev->conns = ZERO_SIZE_PTR
which cannot be verified later to contain a valid pointer. The code which
accesses the csdev->conns is bounded by the csdev->nr_outport check,
hence we don't try to dereference the ZERO_SIZE_PTR. This patch cleans
up the csdev->conns and csdev->refcnt, initialisation to make sure we
initialise it properly(i.e, either NULL or valid conns array).

Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 0fdaaf4..49eb749 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -890,7 +890,7 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
 	int nr_refcnts = 1;
 	atomic_t *refcnts = NULL;
 	struct coresight_device *csdev;
-	struct coresight_connection *conns;
+	struct coresight_connection *conns = NULL;
 
 	csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
 	if (!csdev) {
@@ -918,16 +918,20 @@ struct coresight_device *coresight_register(struct coresight_desc *desc)
 
 	csdev->nr_inport = desc->pdata->nr_inport;
 	csdev->nr_outport = desc->pdata->nr_outport;
-	conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
-	if (!conns) {
-		ret = -ENOMEM;
-		goto err_kzalloc_conns;
-	}
 
-	for (i = 0; i < csdev->nr_outport; i++) {
-		conns[i].outport = desc->pdata->outports[i];
-		conns[i].child_name = desc->pdata->child_names[i];
-		conns[i].child_port = desc->pdata->child_ports[i];
+	/* Initialise connections if there is at least one outport */
+	if (csdev->nr_outport) {
+		conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
+		if (!conns) {
+			ret = -ENOMEM;
+			goto err_kzalloc_conns;
+		}
+
+		for (i = 0; i < csdev->nr_outport; i++) {
+			conns[i].outport = desc->pdata->outports[i];
+			conns[i].child_name = desc->pdata->child_names[i];
+			conns[i].child_port = desc->pdata->child_ports[i];
+		}
 	}
 
 	csdev->conns = conns;
-- 
1.9.1

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#1414817 — [PATCH v2 2/9] coresight: Fix tmc_read_unprepare_etr

At the end of the trace capture, we free the allocated memory,
resetting the drvdata->buf to NULL, to indicate that trace data
was collected and the next trace session should allocate the
memory in tmc_enable_etr_sink_sysfs.

The tmc_enable_etr_sink_sysfs, we only allocate memory if drvdata->vaddr
is not NULL (which is not performed at the end of previous session).
This can cause, drvdata->vaddr getting assigned NULL and later we do
memset() which causes a crash as below :

Unable to handle kernel NULL pointer dereference at virtual
 address  00000000
pgd = ffffffc9747f0000
[00000000] *pgd=00000009f402e003, *pud=00000009f402e003,
 *pmd=0000000000000000
Internal error: Oops: 96000046 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 1592 Comm: bash Not tainted 4.7.0-rc1+ #1712
Hardware name: ARM Juno development board (r0) (DT)
task: ffffffc078fe0080 ti: ffffffc974178000 task.ti: ffffffc974178000
PC is at __memset+0x1ac/0x200
LR is at tmc_enable_etr_sink+0xf8/0x304
pc : [<ffffff80083a002c>] lr : [<ffffff800859be44>] pstate: 400001c5
sp : ffffffc97417bc00
x29: ffffffc97417bc00 x28: ffffffc974178000

Call trace:
Exception stack(0xffffffc97417ba40 to 0xffffffc97417bb60)
ba40: 0000000000000001 ffffffc974a5d098 ffffffc97417bc00 ffffff80083a002c
ba60: ffffffc974a5d118 0000000000000000 0000000000000000 0000000000000000
ba80: 0000000000000001 0000000000000000 ffffff800859bdec 0000000000000040
baa0: ffffff8008b45b58 00000000000001c0 ffffffc97417baf0 ffffff80080eddb4
bac0: 0000000000000003 ffffffc078fe0080 ffffffc078fe0960 ffffffc078fe0940
bae0: 0000000000000000 0000000000000000 00000000007fffc0 0000000000000004
bb00: 0000000000000000 0000000000000040 000000000000003f 0000000000000000
bb20: 0000000000000000 0000000000000000 0000000000000000 0000000000000001
bb40: ffffffc078fe0960 0000000000000018 ffffffffffffffff 0008669628000000
[<ffffff80083a002c>] __memset+0x1ac/0x200
[<ffffff8008599814>] coresight_enable_path+0xa8/0x1dc
[<ffffff8008599b10>] coresight_enable+0x88/0x1b8
[<ffffff8008599d88>] enable_source_store+0x3c/0x6c
[<ffffff800845eaf4>] dev_attr_store+0x18/0x28
[<ffffff80082829e8>] sysfs_kf_write+0x54/0x64
[<ffffff8008281c30>] kernfs_fop_write+0x148/0x1d8
[<ffffff8008200128>] __vfs_write+0x28/0x110
[<ffffff8008200e88>] vfs_write+0xa0/0x198
[<ffffff80082021b0>] SyS_write+0x44/0xa0
[<ffffff8008084e70>] el0_svc_naked+0x24/0x28
Code: 91010108 54ffff4a 8b040108 cb050042 (d50b7428)

This patch fixes the issue by clearing the drvdata->vaddr while we free
the allocated buffer at the end of a session, so that we allocate the
memory again.

Cc: mathieu.poirier@linaro.org
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 847d1b5..3369d7a 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -315,7 +315,7 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
 		 */
 		vaddr = drvdata->vaddr;
 		paddr = drvdata->paddr;
-		drvdata->buf = NULL;
+		drvdata->buf = drvdata->vaddr = NULL;
 	}
 
 	drvdata->reading = false;
-- 
1.9.1

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#1419247 — [PATCH] coresight: Fix erroneous memset in tmc_read_unprepare_etr

At the end of a trace collection, we try to clear the entire buffer
and enable the ETR back if it was already enabled. But, we would have
adjusted the drvdata->buf to point to the beginning of the trace data
in the trace buffer @drvdata->vaddr. So, the following code which
clears the buffer is dangerous and can cause crashes, like below :

	memset(drvdata->buf, 0, drvdata->size);

 Unable to handle kernel paging request at virtual address ffffff800a145000
 pgd = ffffffc974726000
 *pgd=00000009f3e91003, *pud=00000009f3e91003, *pmd=0000000000000000
 PREEMPT SMP
 Modules linked in:
 CPU: 4 PID: 1692 Comm: dd Not tainted 4.7.0-rc2+ #1721
 Hardware name: ARM Juno development board (r0) (DT)
 task: ffffffc9734a0080 ti: ffffffc974460000 task.ti: ffffffc974460000
 PC is at __memset+0x1ac/0x200
 LR is at tmc_read_unprepare_etr+0x144/0x1bc
 pc : [<ffffff80083a05ac>] lr : [<ffffff800859c984>] pstate: 200001c5
 ...
 [<ffffff80083a05ac>] __memset+0x1ac/0x200
 [<ffffff800859b2e4>] tmc_release+0x90/0x94
 [<ffffff8008202f58>] __fput+0xa8/0x1ec
 [<ffffff80082030f4>] ____fput+0xc/0x14
 [<ffffff80080c3ef8>] task_work_run+0xb0/0xe4
 [<ffffff8008088bf4>] do_notify_resume+0x64/0x6c
 [<ffffff8008084d5c>] work_pending+0x10/0x14
 Code: 91010108 54ffff4a 8b040108 cb050042 (d50b7428)

Since we clear the buffer anyway in the following call to
tmc_etr_enable_hw(), remove the erroneous memset().

Fixes: commit de5461970b3e9e1 ("coresight: tmc: allocating memory when needed")
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---

Mathieu,

I think this should go to 4.7. Please push it.

---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 69e104b..24d99ed 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -306,13 +306,10 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
 	if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
 		/*
 		 * The trace run will continue with the same allocated trace
-		 * buffer. As such zero-out the buffer so that we don't end
-		 * up with stale data.
-		 *
-		 * Since the tracer is still enabled drvdata::buf
-		 * can't be NULL.
+		 * buffer. The trace buffer is cleared in tmc_etr_enable_hw(),
+		 * so we don't have to explicitly clear it. Also, since the
+		 * tracer is still enabled drvdata::buf can't be NULL.
 		 */
-		memset(drvdata->buf, 0, drvdata->size);
 		tmc_etr_enable_hw(drvdata);
 	} else {
 		/*
-- 
1.9.1

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