[PATCH v6 5/7] coresight: tmc: Add support for reading tracedata from previous boot
Linu Cherian
lcherian at marvell.com
Thu Jan 4 21:58:38 PST 2024
* Introduce a new mode CS_MODE_READ_PREVBOOT for reading tracedata
captured in previous boot.
* Add special handlers for preparing ETR/ETF for this special mode
* User can read the trace data as below
For example, for reading trace data from tmc_etf sink
1. cd /sys/bus/coresight/devices/tmc_etfXX/
2. Change mode to READ_PREVBOOT
#echo 1 > read_prevboot
3. Dump trace buffer data to a file,
#dd if=/dev/tmc_etfXX of=~/cstrace.bin
4. Reset back to normal mode
#echo 0 > read_prevboot
Signed-off-by: Anil Kumar Reddy <areddy3 at marvell.com>
Signed-off-by: Tanmay Jagdale <tanmay at marvell.com>
Signed-off-by: Linu Cherian <lcherian at marvell.com>
---
Changelog from v5:
* Fixed issues reported by CONFIG_DEBUG_ATOMIC_SLEEP in tmc_etr_setup_prevboot_buf
and tmc_etb_setup_prevboot_buf
- Kmalloc invoked with spinlock taken is now done with GFP_ATOMIC
- Removed the requirement for memremap with spinlock taken. This is by
making a assumption that the trace buffer address used for capturing
trace data during kernel crash/hang would be same as that used
for trace data retrieval in the subsequent boot. Added additional
verification to ensure this.
* Fixed a memory leak in tmc_read_unprepare_etr in READ_PREVBOOT mode
.../coresight/coresight-etm4x-core.c | 1 +
.../hwtracing/coresight/coresight-tmc-core.c | 96 ++++++++++-
.../hwtracing/coresight/coresight-tmc-etf.c | 73 +++++++++
.../hwtracing/coresight/coresight-tmc-etr.c | 154 +++++++++++++++++-
drivers/hwtracing/coresight/coresight-tmc.h | 6 +
include/linux/coresight.h | 13 ++
6 files changed, 341 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 34aee59dd147..c26b5f72a494 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1010,6 +1010,7 @@ static void etm4_disable(struct coresight_device *csdev,
switch (mode) {
case CS_MODE_DISABLED:
+ case CS_MODE_READ_PREVBOOT:
break;
case CS_MODE_SYSFS:
etm4_disable_sysfs(csdev);
diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index 4d7530d6ac91..e6525c3dcf66 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -103,6 +103,60 @@ u32 tmc_get_memwidth_mask(struct tmc_drvdata *drvdata)
return mask;
}
+int tmc_read_prepare_prevboot(struct tmc_drvdata *drvdata)
+{
+ int ret = 0;
+ struct tmc_crash_metadata *mdata;
+ struct coresight_device *csdev = drvdata->csdev;
+
+ if (!drvdata->crash_mdata.vaddr) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ mdata = drvdata->crash_mdata.vaddr;
+ /* Check data integrity of metadata */
+ if (mdata->crc32_mdata != find_crash_metadata_crc(mdata)) {
+ dev_dbg(&drvdata->csdev->dev,
+ "CRC mismatch in tmc crash metadata\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ /* Check data integrity of tracedata */
+ if (mdata->crc32_tdata != find_crash_tracedata_crc(drvdata, mdata)) {
+ dev_dbg(&drvdata->csdev->dev,
+ "CRC mismatch in tmc crash tracedata\n");
+ ret = -EINVAL;
+ goto out;
+ }
+ /* Check for valid metadata */
+ if (!mdata->valid) {
+ dev_dbg(&drvdata->csdev->dev,
+ "Data invalid in tmc crash metadata\n");
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /* Sink specific prevboot mode preparation */
+ ret = prevboot_ops(csdev)->prepare(csdev);
+ if (ret)
+ goto out;
+
+ if (mdata->sts & 0x1)
+ coresight_insert_barrier_packet(drvdata->buf);
+
+out:
+ return ret;
+}
+
+int tmc_read_unprepare_prevboot(struct tmc_drvdata *drvdata)
+{
+ struct coresight_device *csdev = drvdata->csdev;
+
+ /* Sink specific prevboot mode preparation */
+ return prevboot_ops(csdev)->unprepare(csdev);
+}
+
static int tmc_read_prepare(struct tmc_drvdata *drvdata)
{
int ret = 0;
@@ -153,6 +207,10 @@ static int tmc_open(struct inode *inode, struct file *file)
struct tmc_drvdata *drvdata = container_of(file->private_data,
struct tmc_drvdata, miscdev);
+ /* Advertise if we are opening with a special mode */
+ if (drvdata->mode == CS_MODE_READ_PREVBOOT)
+ dev_dbg(&drvdata->csdev->dev, "TMC read mode for previous boot\n");
+
ret = tmc_read_prepare(drvdata);
if (ret)
return ret;
@@ -331,9 +389,44 @@ static ssize_t buffer_size_store(struct device *dev,
static DEVICE_ATTR_RW(buffer_size);
+static ssize_t read_prevboot_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+ return sprintf(buf, "%#x\n", (drvdata->mode == CS_MODE_READ_PREVBOOT));
+}
+
+static ssize_t read_prevboot_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ int ret;
+ unsigned long val, flags;
+ struct tmc_drvdata *drvdata = dev_get_drvdata(dev->parent);
+
+ ret = kstrtoul(buf, 0, &val);
+ if (ret)
+ return ret;
+
+ spin_lock_irqsave(&drvdata->spinlock, flags);
+
+ if (val && (drvdata->mode == CS_MODE_DISABLED))
+ drvdata->mode = CS_MODE_READ_PREVBOOT;
+ else if (!val && (drvdata->mode == CS_MODE_READ_PREVBOOT))
+ drvdata->mode = CS_MODE_DISABLED;
+
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+
+ return size;
+}
+
+static DEVICE_ATTR_RW(read_prevboot);
+
static struct attribute *coresight_tmc_attrs[] = {
&dev_attr_trigger_cntr.attr,
&dev_attr_buffer_size.attr,
+ &dev_attr_read_prevboot.attr,
NULL,
};
@@ -635,7 +728,8 @@ static void tmc_shutdown(struct amba_device *adev)
spin_lock_irqsave(&drvdata->spinlock, flags);
- if (drvdata->mode == CS_MODE_DISABLED)
+ if (drvdata->mode == CS_MODE_DISABLED ||
+ drvdata->mode == CS_MODE_READ_PREVBOOT)
goto out;
if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index b53cef7628ff..72c2315f4e23 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -648,6 +648,56 @@ static int tmc_panic_sync_etf(struct coresight_device *csdev)
return 0;
}
+static int tmc_etb_setup_prevboot_buf(struct tmc_drvdata *drvdata)
+{
+ unsigned long size;
+ struct tmc_crash_metadata *mdata;
+ struct device *dev = &drvdata->csdev->dev;
+
+ mdata = drvdata->crash_mdata.vaddr;
+ size = mdata->size << 2;
+
+ /*
+ * Buffer address given by metadata for retrieval of trace data
+ * from previous boot is expected to be same as the reserved
+ * trace buffer memory region provided through DTS
+ */
+ if (is_tmc_reserved_region_valid(dev->parent)
+ && (drvdata->crash_tbuf.paddr == mdata->trc_paddr))
+ drvdata->buf = drvdata->crash_tbuf.vaddr;
+ else {
+ dev_dbg(dev, "Trace buffer address of previous boot invalid\n");
+ return -EINVAL;
+ }
+
+ drvdata->len = size;
+ return 0;
+}
+
+static void tmc_etb_free_prevboot_buf(struct tmc_drvdata *drvdata)
+{
+ void *buf = drvdata->buf;
+
+ if (!buf)
+ return;
+ drvdata->buf = NULL;
+}
+
+static int tmc_etb_prepare_prevboot(struct coresight_device *csdev)
+{
+ struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ return tmc_etb_setup_prevboot_buf(drvdata);
+}
+
+static int tmc_etb_unprepare_prevboot(struct coresight_device *csdev)
+{
+ struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ tmc_etb_free_prevboot_buf(drvdata);
+ return 0;
+}
+
static const struct coresight_ops_sink tmc_etf_sink_ops = {
.enable = tmc_enable_etf_sink,
.disable = tmc_disable_etf_sink,
@@ -665,6 +715,11 @@ static const struct coresight_ops_panic tmc_etf_sync_ops = {
.sync = tmc_panic_sync_etf,
};
+static const struct coresight_ops_prevboot tmc_etf_prevboot_ops = {
+ .prepare = tmc_etb_prepare_prevboot,
+ .unprepare = tmc_etb_unprepare_prevboot,
+};
+
const struct coresight_ops tmc_etb_cs_ops = {
.sink_ops = &tmc_etf_sink_ops,
};
@@ -673,6 +728,7 @@ const struct coresight_ops tmc_etf_cs_ops = {
.sink_ops = &tmc_etf_sink_ops,
.link_ops = &tmc_etf_link_ops,
.panic_ops = &tmc_etf_sync_ops,
+ .prevboot_ops = &tmc_etf_prevboot_ops,
};
int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
@@ -693,6 +749,14 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
goto out;
}
+ if (drvdata->mode == CS_MODE_READ_PREVBOOT) {
+ ret = tmc_read_prepare_prevboot(drvdata);
+ if (ret)
+ goto out;
+ else
+ goto mode_valid;
+ }
+
/* Don't interfere if operated from Perf */
if (drvdata->mode == CS_MODE_PERF) {
ret = -EINVAL;
@@ -716,6 +780,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
__tmc_etb_disable_hw(drvdata);
}
+mode_valid:
drvdata->reading = true;
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -735,8 +800,16 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
drvdata->config_type != TMC_CONFIG_TYPE_ETF))
return -EINVAL;
+
spin_lock_irqsave(&drvdata->spinlock, flags);
+ if (drvdata->mode == CS_MODE_READ_PREVBOOT) {
+ tmc_read_unprepare_prevboot(drvdata);
+ drvdata->reading = false;
+ spin_unlock_irqrestore(&drvdata->spinlock, flags);
+ return 0;
+ }
+
/* Re-enable the TMC if need be */
if (drvdata->mode == CS_MODE_SYSFS) {
/* There is no point in reading a TMC in HW FIFO mode */
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 23eb35f50571..ab7521bbb2f5 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1166,7 +1166,12 @@ ssize_t tmc_etr_get_sysfs_trace(struct tmc_drvdata *drvdata,
{
s64 offset;
ssize_t actual = len;
- struct etr_buf *etr_buf = drvdata->sysfs_buf;
+ struct etr_buf *etr_buf;
+
+ if (drvdata->mode == CS_MODE_READ_PREVBOOT)
+ etr_buf = drvdata->prevboot_buf;
+ else
+ etr_buf = drvdata->sysfs_buf;
if (pos + actual > etr_buf->len)
actual = etr_buf->len - pos;
@@ -1873,6 +1878,130 @@ static int tmc_panic_sync_etr(struct coresight_device *csdev)
return 0;
}
+static int tmc_etr_setup_prevboot_buf(struct tmc_drvdata *drvdata)
+{
+ int rc = 0;
+ u64 trace_addr;
+ struct etr_buf *etr_buf;
+ struct etr_flat_buf *resrv_buf;
+ struct tmc_crash_metadata *mdata;
+ struct device *dev = &drvdata->csdev->dev;
+
+ mdata = drvdata->crash_mdata.vaddr;
+
+ etr_buf = kzalloc(sizeof(*etr_buf), GFP_ATOMIC);
+ if (!etr_buf) {
+ rc = -ENOMEM;
+ goto out;
+ }
+ etr_buf->size = drvdata->crash_tbuf.size;
+
+ resrv_buf = kzalloc(sizeof(*resrv_buf), GFP_ATOMIC);
+ if (!resrv_buf) {
+ rc = -ENOMEM;
+ goto rmem_err;
+ }
+
+ /*
+ * Buffer address given by metadata for retrieval of trace data
+ * from previous boot is expected to be same as the reserved
+ * trace buffer memory region provided through DTS
+ */
+ if (is_tmc_reserved_region_valid(dev->parent)
+ && (drvdata->crash_tbuf.paddr == mdata->trc_paddr))
+ resrv_buf->vaddr = drvdata->crash_tbuf.vaddr;
+ else {
+ dev_dbg(dev, "Trace buffer address of previous boot invalid\n");
+ rc = -EINVAL;
+ goto map_err;
+ }
+
+ resrv_buf->size = etr_buf->size;
+ resrv_buf->dev = &drvdata->csdev->dev;
+ etr_buf->hwaddr = trace_addr;
+ etr_buf->mode = ETR_MODE_RESRV;
+ etr_buf->private = resrv_buf;
+ etr_buf->ops = etr_buf_ops[ETR_MODE_RESRV];
+
+ drvdata->prevboot_buf = etr_buf;
+
+ return 0;
+
+map_err:
+ kfree(resrv_buf);
+
+rmem_err:
+ kfree(etr_buf);
+
+out:
+ return rc;
+}
+
+static int tmc_etr_sync_prevboot_buf(struct tmc_drvdata *drvdata)
+{
+ u32 status;
+ u64 rrp, rwp, dba;
+ struct tmc_crash_metadata *mdata;
+ struct etr_buf *etr_buf = drvdata->prevboot_buf;
+
+ mdata = drvdata->crash_mdata.vaddr;
+
+ rrp = mdata->rrp;
+ rwp = mdata->rwp;
+ dba = mdata->dba;
+ status = mdata->sts;
+
+ etr_buf->full = !!(status & TMC_STS_FULL);
+
+ /* Sync the buffer pointers */
+ etr_buf->offset = rrp - dba;
+ if (etr_buf->full)
+ etr_buf->len = etr_buf->size;
+ else
+ etr_buf->len = rwp - rrp;
+
+ /* Additional sanity checks for validating metadata */
+ if ((etr_buf->offset > etr_buf->size) ||
+ (etr_buf->len > etr_buf->size)) {
+ dev_dbg(&drvdata->csdev->dev,
+ "Offset and length invalid in tmc crash metadata\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void tmc_etr_free_prevboot_buf(struct tmc_drvdata *drvdata)
+{
+ struct etr_buf *etr_buf = drvdata->prevboot_buf;
+
+ if (!etr_buf)
+ return;
+ drvdata->prevboot_buf = NULL;
+}
+
+static int tmc_etr_prepare_prevboot(struct coresight_device *csdev)
+{
+ int ret = 0;
+ struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ ret = tmc_etr_setup_prevboot_buf(drvdata);
+ if (ret)
+ goto out;
+ ret = tmc_etr_sync_prevboot_buf(drvdata);
+
+out:
+ return ret;
+}
+
+static int tmc_etr_unprepare_prevboot(struct coresight_device *csdev)
+{
+ struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ tmc_etr_free_prevboot_buf(drvdata);
+ return 0;
+}
+
static const struct coresight_ops_sink tmc_etr_sink_ops = {
.enable = tmc_enable_etr_sink,
.disable = tmc_disable_etr_sink,
@@ -1885,9 +2014,15 @@ static const struct coresight_ops_panic tmc_etr_sync_ops = {
.sync = tmc_panic_sync_etr,
};
+static const struct coresight_ops_prevboot tmc_etr_prevboot_ops = {
+ .prepare = tmc_etr_prepare_prevboot,
+ .unprepare = tmc_etr_unprepare_prevboot,
+};
+
const struct coresight_ops tmc_etr_cs_ops = {
.sink_ops = &tmc_etr_sink_ops,
.panic_ops = &tmc_etr_sync_ops,
+ .prevboot_ops = &tmc_etr_prevboot_ops,
};
int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
@@ -1899,12 +2034,21 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETR))
return -EINVAL;
+
spin_lock_irqsave(&drvdata->spinlock, flags);
if (drvdata->reading) {
ret = -EBUSY;
goto out;
}
+ if (drvdata->mode == CS_MODE_READ_PREVBOOT) {
+ ret = tmc_read_prepare_prevboot(drvdata);
+ if (ret)
+ goto out;
+ else
+ goto mode_valid;
+ }
+
/*
* We can safely allow reads even if the ETR is operating in PERF mode,
* since the sysfs session is captured in mode specific data.
@@ -1919,6 +2063,7 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
if (drvdata->mode == CS_MODE_SYSFS)
__tmc_etr_disable_hw(drvdata);
+mode_valid:
drvdata->reading = true;
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -1937,6 +2082,12 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
spin_lock_irqsave(&drvdata->spinlock, flags);
+ if (drvdata->mode == CS_MODE_READ_PREVBOOT) {
+ sysfs_buf = drvdata->prevboot_buf;
+ tmc_read_unprepare_prevboot(drvdata);
+ goto out;
+ }
+
/* RE-enable the TMC if need be */
if (drvdata->mode == CS_MODE_SYSFS) {
/*
@@ -1954,6 +2105,7 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
drvdata->sysfs_buf = NULL;
}
+out:
drvdata->reading = false;
spin_unlock_irqrestore(&drvdata->spinlock, flags);
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 6f13caae6495..6e1e910d5ea4 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -216,6 +216,9 @@ struct tmc_resrv_buf {
* @idr_mutex: Access serialisation for idr.
* @sysfs_buf: SYSFS buffer for ETR.
* @perf_buf: PERF buffer for ETR.
+ * @prevboot_buf: Previous boot buffer for ETR. This is a special purpose
+ * buffer that is used only for mapping the trace buffer from
+ * previous boot and not for capturing trace.
* @crash_tbuf: Used by ETR as hardware trace buffer and for trace data
* retention (after crash) only when ETR_MODE_RESRV buffer
* mode is enabled. Used by ETF for trace data retention
@@ -247,6 +250,7 @@ struct tmc_drvdata {
struct mutex idr_mutex;
struct etr_buf *sysfs_buf;
struct etr_buf *perf_buf;
+ struct etr_buf *prevboot_buf;
struct tmc_resrv_buf crash_tbuf;
struct tmc_resrv_buf crash_mdata;
};
@@ -298,6 +302,8 @@ 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);
u32 tmc_get_memwidth_mask(struct tmc_drvdata *drvdata);
+int tmc_read_prepare_prevboot(struct tmc_drvdata *drvdata);
+int tmc_read_unprepare_prevboot(struct tmc_drvdata *drvdata);
/* ETB/ETF functions */
int tmc_read_prepare_etb(struct tmc_drvdata *drvdata);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 4fd518738958..9f84decf1d7a 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -294,6 +294,7 @@ enum cs_mode {
CS_MODE_DISABLED,
CS_MODE_SYSFS,
CS_MODE_PERF,
+ CS_MODE_READ_PREVBOOT, /* Trace data from previous boot */
};
#define source_ops(csdev) csdev->ops->source_ops
@@ -302,6 +303,7 @@ enum cs_mode {
#define helper_ops(csdev) csdev->ops->helper_ops
#define ect_ops(csdev) csdev->ops->ect_ops
#define panic_ops(csdev) csdev->ops->panic_ops
+#define prevboot_ops(csdev) csdev->ops->prevboot_ops
/**
* struct coresight_ops_sink - basic operations for a sink
@@ -381,12 +383,23 @@ struct coresight_ops_panic {
int (*sync)(struct coresight_device *csdev);
};
+/**
+ * struct coresight_ops_prevboot - Generic device ops for prevboot mode
+ *
+ * @prepare : Preparation for prevboot mode
+ */
+struct coresight_ops_prevboot {
+ int (*prepare)(struct coresight_device *csdev);
+ int (*unprepare)(struct coresight_device *csdev);
+};
+
struct coresight_ops {
const struct coresight_ops_sink *sink_ops;
const struct coresight_ops_link *link_ops;
const struct coresight_ops_source *source_ops;
const struct coresight_ops_helper *helper_ops;
const struct coresight_ops_panic *panic_ops;
+ const struct coresight_ops_prevboot *prevboot_ops;
};
#if IS_ENABLED(CONFIG_CORESIGHT)
--
2.34.1
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