I've been finding it quite difficult to reason about some of the state
and functions in coresight-core.c because they have generic names when
they are actually only relevant to the sysfs usage of Coresight rather
than usage through Perf. This is probably because sysfs came first and
Perf was added later. This has caused a couple of issues where these
things have been used in the wrong context, for example the first
commit is a fixup.
To fix this I've mainly just moved all of the sysfs stuff to the sysfs
file and removed the 'enable' state, which was just for sysfs. While
doing the refactor it became obvious that refcnt didn't need to be
atomic either, so that can be simplified along with some other comment
clarifications and simplifications.
Hopefully it's also a step towards to removing all of the duplicate
refcnt and mode tracking code from the individual devices. That tracking
pretty much always results in a one-shot enable/disable and fixes the
mode to either sysfs or Perf, and there is no reason that can't exist in
the core layer outside of the devices. I tried to finish that in this
set, but there turned out to be some complexities, so I cut it short at
a point where I can be sure that there are no behavioral changes.
James Clark (8):
coresight: Fix issue where a source device's helpers aren't disabled
coresight: Make language around "activated" sinks consistent
coresight: Remove ops callback checks
coresight: Move mode to struct coresight_device
coresight: Remove the 'enable' field.
coresight: Move all sysfs code to sysfs file
coresight: Remove atomic type from refcnt
coresight: Remove unused stubs
drivers/hwtracing/coresight/coresight-core.c | 494 +-----------------
drivers/hwtracing/coresight/coresight-etb10.c | 29 +-
.../hwtracing/coresight/coresight-etm-perf.c | 2 +-
drivers/hwtracing/coresight/coresight-etm.h | 2 -
.../coresight/coresight-etm3x-core.c | 17 +-
.../coresight/coresight-etm3x-sysfs.c | 4 +-
.../coresight/coresight-etm4x-core.c | 4 +-
drivers/hwtracing/coresight/coresight-priv.h | 9 +-
drivers/hwtracing/coresight/coresight-stm.c | 24 +-
drivers/hwtracing/coresight/coresight-sysfs.c | 391 ++++++++++++++
.../hwtracing/coresight/coresight-tmc-core.c | 2 +-
.../hwtracing/coresight/coresight-tmc-etf.c | 46 +-
.../hwtracing/coresight/coresight-tmc-etr.c | 33 +-
drivers/hwtracing/coresight/coresight-tmc.h | 2 -
drivers/hwtracing/coresight/coresight-tpda.c | 13 +-
drivers/hwtracing/coresight/coresight-tpiu.c | 14 +-
drivers/hwtracing/coresight/ultrasoc-smb.c | 22 +-
drivers/hwtracing/coresight/ultrasoc-smb.h | 2 -
include/linux/coresight.h | 114 +---
19 files changed, 561 insertions(+), 663 deletions(-)
--
2.34.1
The check for the existence of callbacks before using them implies that
this happens and is supported. There are no devices without
enable/disable callbacks, and it wouldn't be possible to add a new
working device without adding them either, so just remove them.
Furthermore, there are more callbacks than just enable and disable that
are already used unguarded in other places.
The comment about new session compatibility doesn't seem to match up to
the line of code that it's on so remove it. I think it's alluding to the
fact that sinks will check if they were already enabled via sysfs or
Perf and fail the enable. But there are more detailed comments at those
places, and this one isn't very useful.
Signed-off-by: James Clark <[email protected]>
---
drivers/hwtracing/coresight/coresight-core.c | 51 +++++---------------
1 file changed, 12 insertions(+), 39 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index f79aa9ff9b64..ab226441e5f4 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -279,16 +279,8 @@ EXPORT_SYMBOL_GPL(coresight_add_helper);
static int coresight_enable_sink(struct coresight_device *csdev,
enum cs_mode mode, void *data)
{
- int ret;
-
- /*
- * We need to make sure the "new" session is compatible with the
- * existing "mode" of operation.
- */
- if (!sink_ops(csdev)->enable)
- return -EINVAL;
+ int ret = sink_ops(csdev)->enable(csdev, mode, data);
- ret = sink_ops(csdev)->enable(csdev, mode, data);
if (ret)
return ret;
@@ -299,12 +291,7 @@ static int coresight_enable_sink(struct coresight_device *csdev,
static void coresight_disable_sink(struct coresight_device *csdev)
{
- int ret;
-
- if (!sink_ops(csdev)->disable)
- return;
-
- ret = sink_ops(csdev)->disable(csdev);
+ int ret = sink_ops(csdev)->disable(csdev);
if (ret)
return;
csdev->enable = false;
@@ -330,11 +317,9 @@ static int coresight_enable_link(struct coresight_device *csdev,
if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && IS_ERR(outconn))
return PTR_ERR(outconn);
- if (link_ops(csdev)->enable) {
- ret = link_ops(csdev)->enable(csdev, inconn, outconn);
- if (!ret)
- csdev->enable = true;
- }
+ ret = link_ops(csdev)->enable(csdev, inconn, outconn);
+ if (!ret)
+ csdev->enable = true;
return ret;
}
@@ -354,9 +339,7 @@ static void coresight_disable_link(struct coresight_device *csdev,
outconn = coresight_find_out_connection(csdev, child);
link_subtype = csdev->subtype.link_subtype;
- if (link_ops(csdev)->disable) {
- link_ops(csdev)->disable(csdev, inconn, outconn);
- }
+ link_ops(csdev)->disable(csdev, inconn, outconn);
if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
for (i = 0; i < csdev->pdata->nr_inconns; i++)
@@ -382,11 +365,9 @@ int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
int ret;
if (!csdev->enable) {
- if (source_ops(csdev)->enable) {
- ret = source_ops(csdev)->enable(csdev, data, mode);
- if (ret)
- return ret;
- }
+ ret = source_ops(csdev)->enable(csdev, data, mode);
+ if (ret)
+ return ret;
csdev->enable = true;
}
@@ -404,11 +385,8 @@ static bool coresight_is_helper(struct coresight_device *csdev)
static int coresight_enable_helper(struct coresight_device *csdev,
enum cs_mode mode, void *data)
{
- int ret;
+ int ret = helper_ops(csdev)->enable(csdev, mode, data);
- if (!helper_ops(csdev)->enable)
- return 0;
- ret = helper_ops(csdev)->enable(csdev, mode, data);
if (ret)
return ret;
@@ -418,12 +396,8 @@ static int coresight_enable_helper(struct coresight_device *csdev,
static void coresight_disable_helper(struct coresight_device *csdev)
{
- int ret;
-
- if (!helper_ops(csdev)->disable)
- return;
+ int ret = helper_ops(csdev)->disable(csdev, NULL);
- ret = helper_ops(csdev)->disable(csdev, NULL);
if (ret)
return;
csdev->enable = false;
@@ -453,8 +427,7 @@ static void coresight_disable_helpers(struct coresight_device *csdev)
*/
void coresight_disable_source(struct coresight_device *csdev, void *data)
{
- if (source_ops(csdev)->disable)
- source_ops(csdev)->disable(csdev, data);
+ source_ops(csdev)->disable(csdev, data);
coresight_disable_helpers(csdev);
}
EXPORT_SYMBOL_GPL(coresight_disable_source);
--
2.34.1
These are a bit annoying to keep up to date when the function signatures
change. But if CONFIG_CORESIGHT isn't enabled, then they're not used
anyway so just delete them.
Signed-off-by: James Clark <[email protected]>
---
include/linux/coresight.h | 79 ---------------------------------------
1 file changed, 79 deletions(-)
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 4400d554a16b..c5be46d7f85c 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -391,8 +391,6 @@ struct coresight_ops {
const struct coresight_ops_helper *helper_ops;
};
-#if IS_ENABLED(CONFIG_CORESIGHT)
-
static inline u32 csdev_access_relaxed_read32(struct csdev_access *csa,
u32 offset)
{
@@ -611,83 +609,6 @@ void coresight_relaxed_write64(struct coresight_device *csdev,
u64 val, u32 offset);
void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset);
-#else
-static inline struct coresight_device *
-coresight_register(struct coresight_desc *desc) { return NULL; }
-static inline void coresight_unregister(struct coresight_device *csdev) {}
-static inline int
-coresight_enable_sysfs(struct coresight_device *csdev) { return -ENOSYS; }
-static inline void coresight_disable_sysfs(struct coresight_device *csdev) {}
-
-static inline int coresight_timeout(struct csdev_access *csa, u32 offset,
- int position, int value)
-{
- return 1;
-}
-
-static inline int coresight_claim_device_unlocked(struct coresight_device *csdev)
-{
- return -EINVAL;
-}
-
-static inline int coresight_claim_device(struct coresight_device *csdev)
-{
- return -EINVAL;
-}
-
-static inline void coresight_disclaim_device(struct coresight_device *csdev) {}
-static inline void coresight_disclaim_device_unlocked(struct coresight_device *csdev) {}
-
-static inline bool coresight_loses_context_with_cpu(struct device *dev)
-{
- return false;
-}
-
-static inline u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset)
-{
- WARN_ON_ONCE(1);
- return 0;
-}
-
-static inline u32 coresight_read32(struct coresight_device *csdev, u32 offset)
-{
- WARN_ON_ONCE(1);
- return 0;
-}
-
-static inline void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset)
-{
-}
-
-static inline void coresight_relaxed_write32(struct coresight_device *csdev,
- u32 val, u32 offset)
-{
-}
-
-static inline u64 coresight_relaxed_read64(struct coresight_device *csdev,
- u32 offset)
-{
- WARN_ON_ONCE(1);
- return 0;
-}
-
-static inline u64 coresight_read64(struct coresight_device *csdev, u32 offset)
-{
- WARN_ON_ONCE(1);
- return 0;
-}
-
-static inline void coresight_relaxed_write64(struct coresight_device *csdev,
- u64 val, u32 offset)
-{
-}
-
-static inline void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
-{
-}
-
-#endif /* IS_ENABLED(CONFIG_CORESIGHT) */
-
extern int coresight_get_cpu(struct device *dev);
struct coresight_platform_data *coresight_get_platform_data(struct device *dev);
--
2.34.1
At the moment the core file contains both sysfs functionality and
core functionality, while the Perf mode is in a separate file in
coresight-etm-perf.c
Many of the functions have ambiguous names like
coresight_enable_source() which actually only work in relation to the
sysfs mode. To avoid further confusion, move everything that isn't core
functionality into the sysfs file and append _sysfs to the ambiguous
functions.
Signed-off-by: James Clark <[email protected]>
---
drivers/hwtracing/coresight/coresight-core.c | 394 +-----------------
.../coresight/coresight-etm3x-core.c | 4 +-
.../coresight/coresight-etm4x-core.c | 4 +-
drivers/hwtracing/coresight/coresight-priv.h | 5 +-
drivers/hwtracing/coresight/coresight-stm.c | 4 +-
drivers/hwtracing/coresight/coresight-sysfs.c | 390 +++++++++++++++++
include/linux/coresight.h | 8 +-
7 files changed, 407 insertions(+), 402 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index 1d0bd1586590..eb72cdd1a273 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -9,7 +9,6 @@
#include <linux/types.h>
#include <linux/device.h>
#include <linux/io.h>
-#include <linux/idr.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/slab.h>
@@ -25,15 +24,12 @@
#include "coresight-priv.h"
#include "coresight-syscfg.h"
-static DEFINE_MUTEX(coresight_mutex);
-static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
-
/*
- * Use IDR to map the hash of the source's device name
- * to the pointer of path for the source. The idr is for
- * the sources which aren't associated with CPU.
+ * Mutex used to lock all sysfs enable and disable actions and loading and
+ * unloading devices by the Coresight core.
*/
-static DEFINE_IDR(path_idr);
+DEFINE_MUTEX(coresight_mutex);
+static DEFINE_PER_CPU(struct coresight_device *, csdev_sink);
/**
* struct coresight_node - elements of a path, from source to sink
@@ -45,12 +41,6 @@ struct coresight_node {
struct list_head link;
};
-/*
- * When operating Coresight drivers from the sysFS interface, only a single
- * path can exist from a tracer (associated to a CPU) to a sink.
- */
-static DEFINE_PER_CPU(struct list_head *, tracer_path);
-
/*
* When losing synchronisation a new barrier packet needs to be inserted at the
* beginning of the data collected in a buffer. That way the decoder knows that
@@ -61,34 +51,6 @@ EXPORT_SYMBOL_GPL(coresight_barrier_pkt);
static const struct cti_assoc_op *cti_assoc_ops;
-ssize_t coresight_simple_show_pair(struct device *_dev,
- struct device_attribute *attr, char *buf)
-{
- struct coresight_device *csdev = container_of(_dev, struct coresight_device, dev);
- struct cs_pair_attribute *cs_attr = container_of(attr, struct cs_pair_attribute, attr);
- u64 val;
-
- pm_runtime_get_sync(_dev->parent);
- val = csdev_access_relaxed_read_pair(&csdev->access, cs_attr->lo_off, cs_attr->hi_off);
- pm_runtime_put_sync(_dev->parent);
- return sysfs_emit(buf, "0x%llx\n", val);
-}
-EXPORT_SYMBOL_GPL(coresight_simple_show_pair);
-
-ssize_t coresight_simple_show32(struct device *_dev,
- struct device_attribute *attr, char *buf)
-{
- struct coresight_device *csdev = container_of(_dev, struct coresight_device, dev);
- struct cs_off_attribute *cs_attr = container_of(attr, struct cs_off_attribute, attr);
- u64 val;
-
- pm_runtime_get_sync(_dev->parent);
- val = csdev_access_relaxed_read32(&csdev->access, cs_attr->off);
- pm_runtime_put_sync(_dev->parent);
- return sysfs_emit(buf, "0x%llx\n", val);
-}
-EXPORT_SYMBOL_GPL(coresight_simple_show32);
-
void coresight_set_cti_ops(const struct cti_assoc_op *cti_op)
{
cti_assoc_ops = cti_op;
@@ -324,29 +286,6 @@ static void coresight_disable_link(struct coresight_device *csdev,
link_ops(csdev)->disable(csdev, inconn, outconn);
}
-int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
- void *data)
-{
- int ret;
-
- /*
- * Comparison with CS_MODE_SYSFS works without taking any device
- * specific spinlock because the truthyness of that comparison can only
- * change with coresight_mutex held, which we already have here.
- */
- lockdep_assert_held(&coresight_mutex);
- if (local_read(&csdev->mode) != CS_MODE_SYSFS) {
- ret = source_ops(csdev)->enable(csdev, data, mode);
- if (ret)
- return ret;
- }
-
- atomic_inc(&csdev->refcnt);
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(coresight_enable_source);
-
static bool coresight_is_helper(struct coresight_device *csdev)
{
return csdev->type == CORESIGHT_DEV_TYPE_HELPER;
@@ -392,30 +331,6 @@ void coresight_disable_source(struct coresight_device *csdev, void *data)
}
EXPORT_SYMBOL_GPL(coresight_disable_source);
-/**
- * coresight_disable_source_sysfs - Drop the reference count by 1 and disable
- * the device if there are no users left.
- *
- * @csdev: The coresight device to disable
- * @data: Opaque data to pass on to the disable function of the source device.
- * For example in perf mode this is a pointer to the struct perf_event.
- *
- * Returns true if the device has been disabled.
- */
-static bool coresight_disable_source_sysfs(struct coresight_device *csdev,
- void *data)
-{
- lockdep_assert_held(&coresight_mutex);
- if (local_read(&csdev->mode) != CS_MODE_SYSFS)
- return false;
-
- if (atomic_dec_return(&csdev->refcnt) == 0) {
- coresight_disable_source(csdev, data);
- return true;
- }
- return false;
-}
-
/*
* coresight_disable_path_from : Disable components in the given path beyond
* @nd in the list. If @nd is NULL, all the components, except the SOURCE are
@@ -572,39 +487,6 @@ struct coresight_device *coresight_get_sink(struct list_head *path)
return csdev;
}
-/**
- * coresight_find_activated_sysfs_sink - returns the first sink activated via
- * sysfs using connection based search starting from the source reference.
- *
- * @csdev: Coresight source device reference
- */
-static struct coresight_device *
-coresight_find_activated_sysfs_sink(struct coresight_device *csdev)
-{
- int i;
- struct coresight_device *sink = NULL;
-
- if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
- csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
- csdev->sysfs_sink_activated)
- return csdev;
-
- /*
- * Recursively explore each port found on this element.
- */
- for (i = 0; i < csdev->pdata->nr_outconns; i++) {
- struct coresight_device *child_dev;
-
- child_dev = csdev->pdata->out_conns[i]->dest_dev;
- if (child_dev)
- sink = coresight_find_activated_sysfs_sink(child_dev);
- if (sink)
- return sink;
- }
-
- return NULL;
-}
-
static int coresight_sink_by_id(struct device *dev, const void *data)
{
struct coresight_device *csdev = to_coresight_device(dev);
@@ -1015,274 +897,6 @@ static void coresight_clear_default_sink(struct coresight_device *csdev)
}
}
-/** coresight_validate_source - make sure a source has the right credentials
- * @csdev: the device structure for a source.
- * @function: the function this was called from.
- *
- * Assumes the coresight_mutex is held.
- */
-static int coresight_validate_source(struct coresight_device *csdev,
- const char *function)
-{
- u32 type, subtype;
-
- type = csdev->type;
- subtype = csdev->subtype.source_subtype;
-
- if (type != CORESIGHT_DEV_TYPE_SOURCE) {
- dev_err(&csdev->dev, "wrong device type in %s\n", function);
- return -EINVAL;
- }
-
- if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
- subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE &&
- subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM &&
- subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS) {
- dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
- return -EINVAL;
- }
-
- return 0;
-}
-
-int coresight_enable(struct coresight_device *csdev)
-{
- int cpu, ret = 0;
- struct coresight_device *sink;
- struct list_head *path;
- enum coresight_dev_subtype_source subtype;
- u32 hash;
-
- subtype = csdev->subtype.source_subtype;
-
- mutex_lock(&coresight_mutex);
-
- ret = coresight_validate_source(csdev, __func__);
- if (ret)
- goto out;
-
- /*
- * mode == SYSFS implies that it's already enabled. Don't look at the
- * refcount to determine this because we don't claim the source until
- * coresight_enable_source() so can still race with Perf mode which
- * doesn't hold coresight_mutex.
- */
- if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
- /*
- * There could be multiple applications driving the software
- * source. So keep the refcount for each such user when the
- * source is already enabled.
- */
- if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
- atomic_inc(&csdev->refcnt);
- goto out;
- }
-
- sink = coresight_find_activated_sysfs_sink(csdev);
- if (!sink) {
- ret = -EINVAL;
- goto out;
- }
-
- path = coresight_build_path(csdev, sink);
- if (IS_ERR(path)) {
- pr_err("building path(s) failed\n");
- ret = PTR_ERR(path);
- goto out;
- }
-
- ret = coresight_enable_path(path, CS_MODE_SYSFS, NULL);
- if (ret)
- goto err_path;
-
- ret = coresight_enable_source(csdev, CS_MODE_SYSFS, NULL);
- if (ret)
- goto err_source;
-
- switch (subtype) {
- case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
- /*
- * When working from sysFS it is important to keep track
- * of the paths that were created so that they can be
- * undone in 'coresight_disable()'. Since there can only
- * be a single session per tracer (when working from sysFS)
- * a per-cpu variable will do just fine.
- */
- cpu = source_ops(csdev)->cpu_id(csdev);
- per_cpu(tracer_path, cpu) = path;
- break;
- case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
- case CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM:
- case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
- /*
- * Use the hash of source's device name as ID
- * and map the ID to the pointer of the path.
- */
- hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
- ret = idr_alloc_u32(&path_idr, path, &hash, hash, GFP_KERNEL);
- if (ret)
- goto err_source;
- break;
- default:
- /* We can't be here */
- break;
- }
-
-out:
- mutex_unlock(&coresight_mutex);
- return ret;
-
-err_source:
- coresight_disable_path(path);
-
-err_path:
- coresight_release_path(path);
- goto out;
-}
-EXPORT_SYMBOL_GPL(coresight_enable);
-
-void coresight_disable(struct coresight_device *csdev)
-{
- int cpu, ret;
- struct list_head *path = NULL;
- u32 hash;
-
- mutex_lock(&coresight_mutex);
-
- ret = coresight_validate_source(csdev, __func__);
- if (ret)
- goto out;
-
- if (!coresight_disable_source_sysfs(csdev, NULL))
- goto out;
-
- switch (csdev->subtype.source_subtype) {
- case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
- cpu = source_ops(csdev)->cpu_id(csdev);
- path = per_cpu(tracer_path, cpu);
- per_cpu(tracer_path, cpu) = NULL;
- break;
- case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
- case CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM:
- case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
- hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
- /* Find the path by the hash. */
- path = idr_find(&path_idr, hash);
- if (path == NULL) {
- pr_err("Path is not found for %s\n", dev_name(&csdev->dev));
- goto out;
- }
- idr_remove(&path_idr, hash);
- break;
- default:
- /* We can't be here */
- break;
- }
-
- coresight_disable_path(path);
- coresight_release_path(path);
-
-out:
- mutex_unlock(&coresight_mutex);
-}
-EXPORT_SYMBOL_GPL(coresight_disable);
-
-static ssize_t enable_sink_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct coresight_device *csdev = to_coresight_device(dev);
-
- return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->sysfs_sink_activated);
-}
-
-static ssize_t enable_sink_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t size)
-{
- int ret;
- unsigned long val;
- struct coresight_device *csdev = to_coresight_device(dev);
-
- ret = kstrtoul(buf, 10, &val);
- if (ret)
- return ret;
-
- csdev->sysfs_sink_activated = !!val;
-
- return size;
-
-}
-static DEVICE_ATTR_RW(enable_sink);
-
-static ssize_t enable_source_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct coresight_device *csdev = to_coresight_device(dev);
-
- guard(mutex)(&coresight_mutex);
- return scnprintf(buf, PAGE_SIZE, "%u\n",
- local_read(&csdev->mode) == CS_MODE_SYSFS);
-}
-
-static ssize_t enable_source_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t size)
-{
- int ret = 0;
- unsigned long val;
- struct coresight_device *csdev = to_coresight_device(dev);
-
- ret = kstrtoul(buf, 10, &val);
- if (ret)
- return ret;
-
- if (val) {
- ret = coresight_enable(csdev);
- if (ret)
- return ret;
- } else {
- coresight_disable(csdev);
- }
-
- return size;
-}
-static DEVICE_ATTR_RW(enable_source);
-
-static struct attribute *coresight_sink_attrs[] = {
- &dev_attr_enable_sink.attr,
- NULL,
-};
-ATTRIBUTE_GROUPS(coresight_sink);
-
-static struct attribute *coresight_source_attrs[] = {
- &dev_attr_enable_source.attr,
- NULL,
-};
-ATTRIBUTE_GROUPS(coresight_source);
-
-static struct device_type coresight_dev_type[] = {
- {
- .name = "sink",
- .groups = coresight_sink_groups,
- },
- {
- .name = "link",
- },
- {
- .name = "linksink",
- .groups = coresight_sink_groups,
- },
- {
- .name = "source",
- .groups = coresight_source_groups,
- },
- {
- .name = "helper",
- }
-};
-/* Ensure the enum matches the names and groups */
-static_assert(ARRAY_SIZE(coresight_dev_type) == CORESIGHT_DEV_TYPE_MAX);
-
static void coresight_device_release(struct device *dev)
{
struct coresight_device *csdev = to_coresight_device(dev);
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index 29f62dfac673..a8be115636f0 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -714,7 +714,7 @@ static int etm_online_cpu(unsigned int cpu)
return 0;
if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
- coresight_enable(etmdrvdata[cpu]->csdev);
+ coresight_enable_sysfs(etmdrvdata[cpu]->csdev);
return 0;
}
@@ -924,7 +924,7 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id)
dev_info(&drvdata->csdev->dev,
"%s initialized\n", (char *)coresight_get_uci_data(id));
if (boot_enable) {
- coresight_enable(drvdata->csdev);
+ coresight_enable_sysfs(drvdata->csdev);
drvdata->boot_enable = true;
}
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index ce1995a2827f..cbb4ac8be133 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -1650,7 +1650,7 @@ static int etm4_online_cpu(unsigned int cpu)
return etm4_probe_cpu(cpu);
if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
- coresight_enable(etmdrvdata[cpu]->csdev);
+ coresight_enable_sysfs(etmdrvdata[cpu]->csdev);
return 0;
}
@@ -2098,7 +2098,7 @@ static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
drvdata->cpu, type_name, major, minor);
if (boot_enable) {
- coresight_enable(drvdata->csdev);
+ coresight_enable_sysfs(drvdata->csdev);
drvdata->boot_enable = true;
}
diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
index ced5be05a527..eb365236f9a9 100644
--- a/drivers/hwtracing/coresight/coresight-priv.h
+++ b/drivers/hwtracing/coresight/coresight-priv.h
@@ -12,6 +12,9 @@
#include <linux/coresight.h>
#include <linux/pm_runtime.h>
+extern struct mutex coresight_mutex;
+extern struct device_type coresight_dev_type[];
+
/*
* Coresight management registers (0xf00-0xfcc)
* 0xfa0 - 0xfa4: Management registers in PFTv1.0
@@ -229,8 +232,6 @@ void coresight_add_helper(struct coresight_device *csdev,
void coresight_set_percpu_sink(int cpu, struct coresight_device *csdev);
struct coresight_device *coresight_get_percpu_sink(int cpu);
-int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
- void *data);
void coresight_disable_source(struct coresight_device *csdev, void *data);
#endif
diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index 190ba569b05a..af9b21224246 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -332,7 +332,7 @@ static int stm_generic_link(struct stm_data *stm_data,
if (!drvdata || !drvdata->csdev)
return -EINVAL;
- return coresight_enable(drvdata->csdev);
+ return coresight_enable_sysfs(drvdata->csdev);
}
static void stm_generic_unlink(struct stm_data *stm_data,
@@ -343,7 +343,7 @@ static void stm_generic_unlink(struct stm_data *stm_data,
if (!drvdata || !drvdata->csdev)
return;
- coresight_disable(drvdata->csdev);
+ coresight_disable_sysfs(drvdata->csdev);
}
static phys_addr_t
diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index dd78e9fcfc4d..92cdf8139f23 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -5,10 +5,400 @@
*/
#include <linux/device.h>
+#include <linux/idr.h>
#include <linux/kernel.h>
#include "coresight-priv.h"
+/*
+ * Use IDR to map the hash of the source's device name
+ * to the pointer of path for the source. The idr is for
+ * the sources which aren't associated with CPU.
+ */
+static DEFINE_IDR(path_idr);
+
+/*
+ * When operating Coresight drivers from the sysFS interface, only a single
+ * path can exist from a tracer (associated to a CPU) to a sink.
+ */
+static DEFINE_PER_CPU(struct list_head *, tracer_path);
+
+ssize_t coresight_simple_show_pair(struct device *_dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct coresight_device *csdev = container_of(_dev, struct coresight_device, dev);
+ struct cs_pair_attribute *cs_attr = container_of(attr, struct cs_pair_attribute, attr);
+ u64 val;
+
+ pm_runtime_get_sync(_dev->parent);
+ val = csdev_access_relaxed_read_pair(&csdev->access, cs_attr->lo_off, cs_attr->hi_off);
+ pm_runtime_put_sync(_dev->parent);
+ return sysfs_emit(buf, "0x%llx\n", val);
+}
+EXPORT_SYMBOL_GPL(coresight_simple_show_pair);
+
+ssize_t coresight_simple_show32(struct device *_dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct coresight_device *csdev = container_of(_dev, struct coresight_device, dev);
+ struct cs_off_attribute *cs_attr = container_of(attr, struct cs_off_attribute, attr);
+ u64 val;
+
+ pm_runtime_get_sync(_dev->parent);
+ val = csdev_access_relaxed_read32(&csdev->access, cs_attr->off);
+ pm_runtime_put_sync(_dev->parent);
+ return sysfs_emit(buf, "0x%llx\n", val);
+}
+EXPORT_SYMBOL_GPL(coresight_simple_show32);
+
+static int coresight_enable_source_sysfs(struct coresight_device *csdev,
+ enum cs_mode mode, void *data)
+{
+ int ret;
+
+ /*
+ * Comparison with CS_MODE_SYSFS works without taking any device
+ * specific spinlock because the truthyness of that comparison can only
+ * change with coresight_mutex held, which we already have here.
+ */
+ lockdep_assert_held(&coresight_mutex);
+ if (local_read(&csdev->mode) != CS_MODE_SYSFS) {
+ ret = source_ops(csdev)->enable(csdev, data, mode);
+ if (ret)
+ return ret;
+ }
+
+ atomic_inc(&csdev->refcnt);
+
+ return 0;
+}
+
+/**
+ * coresight_disable_source_sysfs - Drop the reference count by 1 and disable
+ * the device if there are no users left.
+ *
+ * @csdev: The coresight device to disable
+ * @data: Opaque data to pass on to the disable function of the source device.
+ * For example in perf mode this is a pointer to the struct perf_event.
+ *
+ * Returns true if the device has been disabled.
+ */
+static bool coresight_disable_source_sysfs(struct coresight_device *csdev,
+ void *data)
+{
+ lockdep_assert_held(&coresight_mutex);
+ if (local_read(&csdev->mode) != CS_MODE_SYSFS)
+ return false;
+
+ if (atomic_dec_return(&csdev->refcnt) == 0) {
+ coresight_disable_source(csdev, data);
+ return true;
+ }
+ return false;
+}
+
+/**
+ * coresight_find_activated_sysfs_sink - returns the first sink activated via
+ * sysfs using connection based search starting from the source reference.
+ *
+ * @csdev: Coresight source device reference
+ */
+static struct coresight_device *
+coresight_find_activated_sysfs_sink(struct coresight_device *csdev)
+{
+ int i;
+ struct coresight_device *sink = NULL;
+
+ if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
+ csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
+ csdev->sysfs_sink_activated)
+ return csdev;
+
+ /*
+ * Recursively explore each port found on this element.
+ */
+ for (i = 0; i < csdev->pdata->nr_outconns; i++) {
+ struct coresight_device *child_dev;
+
+ child_dev = csdev->pdata->out_conns[i]->dest_dev;
+ if (child_dev)
+ sink = coresight_find_activated_sysfs_sink(child_dev);
+ if (sink)
+ return sink;
+ }
+
+ return NULL;
+}
+
+/** coresight_validate_source - make sure a source has the right credentials to
+ * be used via sysfs.
+ * @csdev: the device structure for a source.
+ * @function: the function this was called from.
+ *
+ * Assumes the coresight_mutex is held.
+ */
+static int coresight_validate_source_sysfs(struct coresight_device *csdev,
+ const char *function)
+{
+ u32 type, subtype;
+
+ type = csdev->type;
+ subtype = csdev->subtype.source_subtype;
+
+ if (type != CORESIGHT_DEV_TYPE_SOURCE) {
+ dev_err(&csdev->dev, "wrong device type in %s\n", function);
+ return -EINVAL;
+ }
+
+ if (subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_PROC &&
+ subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE &&
+ subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM &&
+ subtype != CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS) {
+ dev_err(&csdev->dev, "wrong device subtype in %s\n", function);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+int coresight_enable_sysfs(struct coresight_device *csdev)
+{
+ int cpu, ret = 0;
+ struct coresight_device *sink;
+ struct list_head *path;
+ enum coresight_dev_subtype_source subtype;
+ u32 hash;
+
+ subtype = csdev->subtype.source_subtype;
+
+ mutex_lock(&coresight_mutex);
+
+ ret = coresight_validate_source_sysfs(csdev, __func__);
+ if (ret)
+ goto out;
+
+ /*
+ * mode == SYSFS implies that it's already enabled. Don't look at the
+ * refcount to determine this because we don't claim the source until
+ * coresight_enable_source() so can still race with Perf mode which
+ * doesn't hold coresight_mutex.
+ */
+ if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
+ /*
+ * There could be multiple applications driving the software
+ * source. So keep the refcount for each such user when the
+ * source is already enabled.
+ */
+ if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
+ atomic_inc(&csdev->refcnt);
+ goto out;
+ }
+
+ sink = coresight_find_activated_sysfs_sink(csdev);
+ if (!sink) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ path = coresight_build_path(csdev, sink);
+ if (IS_ERR(path)) {
+ pr_err("building path(s) failed\n");
+ ret = PTR_ERR(path);
+ goto out;
+ }
+
+ ret = coresight_enable_path(path, CS_MODE_SYSFS, NULL);
+ if (ret)
+ goto err_path;
+
+ ret = coresight_enable_source_sysfs(csdev, CS_MODE_SYSFS, NULL);
+ if (ret)
+ goto err_source;
+
+ switch (subtype) {
+ case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
+ /*
+ * When working from sysFS it is important to keep track
+ * of the paths that were created so that they can be
+ * undone in 'coresight_disable()'. Since there can only
+ * be a single session per tracer (when working from sysFS)
+ * a per-cpu variable will do just fine.
+ */
+ cpu = source_ops(csdev)->cpu_id(csdev);
+ per_cpu(tracer_path, cpu) = path;
+ break;
+ case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
+ case CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM:
+ case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
+ /*
+ * Use the hash of source's device name as ID
+ * and map the ID to the pointer of the path.
+ */
+ hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
+ ret = idr_alloc_u32(&path_idr, path, &hash, hash, GFP_KERNEL);
+ if (ret)
+ goto err_source;
+ break;
+ default:
+ /* We can't be here */
+ break;
+ }
+
+out:
+ mutex_unlock(&coresight_mutex);
+ return ret;
+
+err_source:
+ coresight_disable_path(path);
+
+err_path:
+ coresight_release_path(path);
+ goto out;
+}
+EXPORT_SYMBOL_GPL(coresight_enable_sysfs);
+
+void coresight_disable_sysfs(struct coresight_device *csdev)
+{
+ int cpu, ret;
+ struct list_head *path = NULL;
+ u32 hash;
+
+ mutex_lock(&coresight_mutex);
+
+ ret = coresight_validate_source_sysfs(csdev, __func__);
+ if (ret)
+ goto out;
+
+ if (!coresight_disable_source_sysfs(csdev, NULL))
+ goto out;
+
+ switch (csdev->subtype.source_subtype) {
+ case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
+ cpu = source_ops(csdev)->cpu_id(csdev);
+ path = per_cpu(tracer_path, cpu);
+ per_cpu(tracer_path, cpu) = NULL;
+ break;
+ case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
+ case CORESIGHT_DEV_SUBTYPE_SOURCE_TPDM:
+ case CORESIGHT_DEV_SUBTYPE_SOURCE_OTHERS:
+ hash = hashlen_hash(hashlen_string(NULL, dev_name(&csdev->dev)));
+ /* Find the path by the hash. */
+ path = idr_find(&path_idr, hash);
+ if (path == NULL) {
+ pr_err("Path is not found for %s\n", dev_name(&csdev->dev));
+ goto out;
+ }
+ idr_remove(&path_idr, hash);
+ break;
+ default:
+ /* We can't be here */
+ break;
+ }
+
+ coresight_disable_path(path);
+ coresight_release_path(path);
+
+out:
+ mutex_unlock(&coresight_mutex);
+}
+EXPORT_SYMBOL_GPL(coresight_disable_sysfs);
+
+static ssize_t enable_sink_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct coresight_device *csdev = to_coresight_device(dev);
+
+ return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->sysfs_sink_activated);
+}
+
+static ssize_t enable_sink_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ int ret;
+ unsigned long val;
+ struct coresight_device *csdev = to_coresight_device(dev);
+
+ ret = kstrtoul(buf, 10, &val);
+ if (ret)
+ return ret;
+
+ csdev->sysfs_sink_activated = !!val;
+
+ return size;
+
+}
+static DEVICE_ATTR_RW(enable_sink);
+
+static ssize_t enable_source_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct coresight_device *csdev = to_coresight_device(dev);
+
+ guard(mutex)(&coresight_mutex);
+ return scnprintf(buf, PAGE_SIZE, "%u\n",
+ local_read(&csdev->mode) == CS_MODE_SYSFS);
+}
+
+static ssize_t enable_source_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ int ret = 0;
+ unsigned long val;
+ struct coresight_device *csdev = to_coresight_device(dev);
+
+ ret = kstrtoul(buf, 10, &val);
+ if (ret)
+ return ret;
+
+ if (val) {
+ ret = coresight_enable_sysfs(csdev);
+ if (ret)
+ return ret;
+ } else {
+ coresight_disable_sysfs(csdev);
+ }
+
+ return size;
+}
+static DEVICE_ATTR_RW(enable_source);
+
+static struct attribute *coresight_sink_attrs[] = {
+ &dev_attr_enable_sink.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(coresight_sink);
+
+static struct attribute *coresight_source_attrs[] = {
+ &dev_attr_enable_source.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(coresight_source);
+
+struct device_type coresight_dev_type[] = {
+ {
+ .name = "sink",
+ .groups = coresight_sink_groups,
+ },
+ {
+ .name = "link",
+ },
+ {
+ .name = "linksink",
+ .groups = coresight_sink_groups,
+ },
+ {
+ .name = "source",
+ .groups = coresight_source_groups,
+ },
+ {
+ .name = "helper",
+ }
+};
+/* Ensure the enum matches the names and groups */
+static_assert(ARRAY_SIZE(coresight_dev_type) == CORESIGHT_DEV_TYPE_MAX);
+
/*
* Connections group - links attribute.
* Count of created links between coresight components in the group.
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 46e6667f72ce..e8dd0df98881 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -578,8 +578,8 @@ static inline bool coresight_is_percpu_sink(struct coresight_device *csdev)
extern struct coresight_device *
coresight_register(struct coresight_desc *desc);
extern void coresight_unregister(struct coresight_device *csdev);
-extern int coresight_enable(struct coresight_device *csdev);
-extern void coresight_disable(struct coresight_device *csdev);
+extern int coresight_enable_sysfs(struct coresight_device *csdev);
+extern void coresight_disable_sysfs(struct coresight_device *csdev);
extern int coresight_timeout(struct csdev_access *csa, u32 offset,
int position, int value);
@@ -609,8 +609,8 @@ static inline struct coresight_device *
coresight_register(struct coresight_desc *desc) { return NULL; }
static inline void coresight_unregister(struct coresight_device *csdev) {}
static inline int
-coresight_enable(struct coresight_device *csdev) { return -ENOSYS; }
-static inline void coresight_disable(struct coresight_device *csdev) {}
+coresight_enable_sysfs(struct coresight_device *csdev) { return -ENOSYS; }
+static inline void coresight_disable_sysfs(struct coresight_device *csdev) {}
static inline int coresight_timeout(struct csdev_access *csa, u32 offset,
int position, int value)
--
2.34.1
'enable', which probably should have been 'enabled', is only ever read
in the core code in relation to controlling sources, and specifically
only sources in sysfs mode. Confusingly it's not labelled as such and
relying on it can be a source of bugs like the one fixed by
commit 078dbba3f0c9 ("coresight: Fix crash when Perf and sysfs modes are
used concurrently").
Most importantly, it can only be used when the coresight_mutex is held
which is only done when enabling and disabling paths in sysfs mode, and
not Perf mode. So to prevent its usage spreading and leaking out to
other devices, remove it.
It's use is equivalent to checking if the mode is currently sysfs, as
due to the coresight_mutex lock, mode == CS_MODE_SYSFS can only become
true or untrue when that lock is held, and when mode == CS_MODE_SYSFS
the device is both enabled and in sysfs mode.
The one place it was used outside of the core code is in TPDA, but that
pattern is more appropriately represented using refcounts inside the
device's own spinlock.
Signed-off-by: James Clark <[email protected]>
---
drivers/hwtracing/coresight/coresight-core.c | 86 +++++++-------------
drivers/hwtracing/coresight/coresight-tpda.c | 12 ++-
include/linux/coresight.h | 2 -
3 files changed, 38 insertions(+), 62 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
index ab226441e5f4..1d0bd1586590 100644
--- a/drivers/hwtracing/coresight/coresight-core.c
+++ b/drivers/hwtracing/coresight/coresight-core.c
@@ -279,29 +279,18 @@ EXPORT_SYMBOL_GPL(coresight_add_helper);
static int coresight_enable_sink(struct coresight_device *csdev,
enum cs_mode mode, void *data)
{
- int ret = sink_ops(csdev)->enable(csdev, mode, data);
-
- if (ret)
- return ret;
-
- csdev->enable = true;
-
- return 0;
+ return sink_ops(csdev)->enable(csdev, mode, data);
}
static void coresight_disable_sink(struct coresight_device *csdev)
{
- int ret = sink_ops(csdev)->disable(csdev);
- if (ret)
- return;
- csdev->enable = false;
+ sink_ops(csdev)->disable(csdev);
}
static int coresight_enable_link(struct coresight_device *csdev,
struct coresight_device *parent,
struct coresight_device *child)
{
- int ret = 0;
int link_subtype;
struct coresight_connection *inconn, *outconn;
@@ -317,19 +306,13 @@ static int coresight_enable_link(struct coresight_device *csdev,
if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && IS_ERR(outconn))
return PTR_ERR(outconn);
- ret = link_ops(csdev)->enable(csdev, inconn, outconn);
- if (!ret)
- csdev->enable = true;
-
- return ret;
+ return link_ops(csdev)->enable(csdev, inconn, outconn);
}
static void coresight_disable_link(struct coresight_device *csdev,
struct coresight_device *parent,
struct coresight_device *child)
{
- int i;
- int link_subtype;
struct coresight_connection *inconn, *outconn;
if (!parent || !child)
@@ -337,26 +320,8 @@ static void coresight_disable_link(struct coresight_device *csdev,
inconn = coresight_find_out_connection(parent, csdev);
outconn = coresight_find_out_connection(csdev, child);
- link_subtype = csdev->subtype.link_subtype;
link_ops(csdev)->disable(csdev, inconn, outconn);
-
- if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
- for (i = 0; i < csdev->pdata->nr_inconns; i++)
- if (atomic_read(&csdev->pdata->in_conns[i]->dest_refcnt) !=
- 0)
- return;
- } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
- for (i = 0; i < csdev->pdata->nr_outconns; i++)
- if (atomic_read(&csdev->pdata->out_conns[i]->src_refcnt) !=
- 0)
- return;
- } else {
- if (atomic_read(&csdev->refcnt) != 0)
- return;
- }
-
- csdev->enable = false;
}
int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
@@ -364,11 +329,16 @@ int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
{
int ret;
- if (!csdev->enable) {
+ /*
+ * Comparison with CS_MODE_SYSFS works without taking any device
+ * specific spinlock because the truthyness of that comparison can only
+ * change with coresight_mutex held, which we already have here.
+ */
+ lockdep_assert_held(&coresight_mutex);
+ if (local_read(&csdev->mode) != CS_MODE_SYSFS) {
ret = source_ops(csdev)->enable(csdev, data, mode);
if (ret)
return ret;
- csdev->enable = true;
}
atomic_inc(&csdev->refcnt);
@@ -385,22 +355,12 @@ static bool coresight_is_helper(struct coresight_device *csdev)
static int coresight_enable_helper(struct coresight_device *csdev,
enum cs_mode mode, void *data)
{
- int ret = helper_ops(csdev)->enable(csdev, mode, data);
-
- if (ret)
- return ret;
-
- csdev->enable = true;
- return 0;
+ return helper_ops(csdev)->enable(csdev, mode, data);
}
static void coresight_disable_helper(struct coresight_device *csdev)
{
- int ret = helper_ops(csdev)->disable(csdev, NULL);
-
- if (ret)
- return;
- csdev->enable = false;
+ helper_ops(csdev)->disable(csdev, NULL);
}
static void coresight_disable_helpers(struct coresight_device *csdev)
@@ -445,11 +405,15 @@ EXPORT_SYMBOL_GPL(coresight_disable_source);
static bool coresight_disable_source_sysfs(struct coresight_device *csdev,
void *data)
{
+ lockdep_assert_held(&coresight_mutex);
+ if (local_read(&csdev->mode) != CS_MODE_SYSFS)
+ return false;
+
if (atomic_dec_return(&csdev->refcnt) == 0) {
coresight_disable_source(csdev, data);
- csdev->enable = false;
+ return true;
}
- return !csdev->enable;
+ return false;
}
/*
@@ -1097,7 +1061,13 @@ int coresight_enable(struct coresight_device *csdev)
if (ret)
goto out;
- if (csdev->enable) {
+ /*
+ * mode == SYSFS implies that it's already enabled. Don't look at the
+ * refcount to determine this because we don't claim the source until
+ * coresight_enable_source() so can still race with Perf mode which
+ * doesn't hold coresight_mutex.
+ */
+ if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
/*
* There could be multiple applications driving the software
* source. So keep the refcount for each such user when the
@@ -1183,7 +1153,7 @@ void coresight_disable(struct coresight_device *csdev)
if (ret)
goto out;
- if (!csdev->enable || !coresight_disable_source_sysfs(csdev, NULL))
+ if (!coresight_disable_source_sysfs(csdev, NULL))
goto out;
switch (csdev->subtype.source_subtype) {
@@ -1249,7 +1219,9 @@ static ssize_t enable_source_show(struct device *dev,
{
struct coresight_device *csdev = to_coresight_device(dev);
- return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
+ guard(mutex)(&coresight_mutex);
+ return scnprintf(buf, PAGE_SIZE, "%u\n",
+ local_read(&csdev->mode) == CS_MODE_SYSFS);
}
static ssize_t enable_source_store(struct device *dev,
diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
index 5f82737c37bb..65c70995ab00 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.c
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -148,7 +148,11 @@ static int __tpda_enable(struct tpda_drvdata *drvdata, int port)
CS_UNLOCK(drvdata->base);
- if (!drvdata->csdev->enable)
+ /*
+ * Only do pre-port enable for first port that calls enable when the
+ * device's main refcount is still 0
+ */
+ if (!atomic_read(&drvdata->csdev->refcnt))
tpda_enable_pre_port(drvdata);
ret = tpda_enable_port(drvdata, port);
@@ -169,6 +173,7 @@ static int tpda_enable(struct coresight_device *csdev,
ret = __tpda_enable(drvdata, in->dest_port);
if (!ret) {
atomic_inc(&in->dest_refcnt);
+ atomic_inc(&csdev->refcnt);
dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port);
}
}
@@ -197,9 +202,10 @@ static void tpda_disable(struct coresight_device *csdev,
struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
spin_lock(&drvdata->spinlock);
- if (atomic_dec_return(&in->dest_refcnt) == 0)
+ if (atomic_dec_return(&in->dest_refcnt) == 0) {
__tpda_disable(drvdata, in->dest_port);
-
+ atomic_dec(&csdev->refcnt);
+ }
spin_unlock(&drvdata->spinlock);
dev_dbg(drvdata->dev, "TPDA inport %d disabled\n", in->dest_port);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index ba817f563ff7..46e6667f72ce 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -233,7 +233,6 @@ struct coresight_sysfs_link {
* a non-atomic read would also work.
* @refcnt: keep track of what is in use.
* @orphan: true if the component has connections that haven't been linked.
- * @enable: 'true' if component is currently part of an active path.
* @sysfs_sink_activated: 'true' when a sink has been selected for use via sysfs
* by writing a 1 to the 'enable_sink' file. A sink can be
* activated but not yet enabled. Enabling for a _sink_ happens
@@ -260,7 +259,6 @@ struct coresight_device {
local_t mode;
atomic_t refcnt;
bool orphan;
- bool enable;
/* sink specific fields */
bool sysfs_sink_activated;
struct dev_ext_attribute *ea;
--
2.34.1
Refcnt is only ever accessed from either inside the coresight_mutex, or
the device's spinlock, making the atomic type and atomic_dec_return()
calls confusing and unnecessary. The only point of synchronisation
outside of these two types of locks is already done with a compare and
swap on 'mode', which a comment has been added for.
There was one instance of refcnt being used outside of a lock in TPIU,
but that can easily be fixed by making it the same as all the other
devices and adding a spinlock. Potentially in the future all the
refcounting and locking can be moved up into the core code, and all the
mostly duplicate code from the individual devices can be removed.
Signed-off-by: James Clark <[email protected]>
---
drivers/hwtracing/coresight/coresight-etb10.c | 11 +++++-----
drivers/hwtracing/coresight/coresight-sysfs.c | 7 ++++---
.../hwtracing/coresight/coresight-tmc-etf.c | 20 ++++++++++---------
.../hwtracing/coresight/coresight-tmc-etr.c | 13 ++++++------
drivers/hwtracing/coresight/coresight-tpda.c | 7 ++++---
drivers/hwtracing/coresight/coresight-tpiu.c | 14 +++++++++++--
drivers/hwtracing/coresight/ultrasoc-smb.c | 9 +++++----
include/linux/coresight.h | 13 +++++++++---
8 files changed, 59 insertions(+), 35 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 08e5bba862db..5f2bb95955b7 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -161,7 +161,7 @@ static int etb_enable_sysfs(struct coresight_device *csdev)
local_set(&csdev->mode, CS_MODE_SYSFS);
}
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
out:
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return ret;
@@ -197,7 +197,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data)
* use for this session.
*/
if (drvdata->pid == pid) {
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
goto out;
}
@@ -215,7 +215,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data)
/* Associate with monitored process. */
drvdata->pid = pid;
local_set(&drvdata->csdev->mode, CS_MODE_PERF);
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
}
out:
@@ -354,7 +354,8 @@ static int etb_disable(struct coresight_device *csdev)
spin_lock_irqsave(&drvdata->spinlock, flags);
- if (atomic_dec_return(&csdev->refcnt)) {
+ csdev->refcnt--;
+ if (csdev->refcnt) {
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return -EBUSY;
}
@@ -445,7 +446,7 @@ static unsigned long etb_update_buffer(struct coresight_device *csdev,
spin_lock_irqsave(&drvdata->spinlock, flags);
/* Don't do anything if another tracer is using this sink */
- if (atomic_read(&csdev->refcnt) != 1)
+ if (csdev->refcnt != 1)
goto out;
__etb_disable_hw(drvdata);
diff --git a/drivers/hwtracing/coresight/coresight-sysfs.c b/drivers/hwtracing/coresight/coresight-sysfs.c
index 92cdf8139f23..5992f2c2200a 100644
--- a/drivers/hwtracing/coresight/coresight-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-sysfs.c
@@ -68,7 +68,7 @@ static int coresight_enable_source_sysfs(struct coresight_device *csdev,
return ret;
}
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
return 0;
}
@@ -90,7 +90,8 @@ static bool coresight_disable_source_sysfs(struct coresight_device *csdev,
if (local_read(&csdev->mode) != CS_MODE_SYSFS)
return false;
- if (atomic_dec_return(&csdev->refcnt) == 0) {
+ csdev->refcnt--;
+ if (csdev->refcnt == 0) {
coresight_disable_source(csdev, data);
return true;
}
@@ -190,7 +191,7 @@ int coresight_enable_sysfs(struct coresight_device *csdev)
* source is already enabled.
*/
if (subtype == CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE)
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
goto out;
}
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c
index 2a7e516052a2..f3281c958a57 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -206,7 +206,7 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
* touched.
*/
if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
goto out;
}
@@ -229,7 +229,7 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
ret = tmc_etb_enable_hw(drvdata);
if (!ret) {
local_set(&csdev->mode, CS_MODE_SYSFS);
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
} else {
/* Free up the buffer if we failed to enable */
used = false;
@@ -284,7 +284,7 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
* use for this session.
*/
if (drvdata->pid == pid) {
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
break;
}
@@ -293,7 +293,7 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
/* Associate with monitored process. */
drvdata->pid = pid;
local_set(&csdev->mode, CS_MODE_PERF);
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
}
} while (0);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -338,7 +338,8 @@ static int tmc_disable_etf_sink(struct coresight_device *csdev)
return -EBUSY;
}
- if (atomic_dec_return(&csdev->refcnt)) {
+ csdev->refcnt--;
+ if (csdev->refcnt) {
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return -EBUSY;
}
@@ -371,7 +372,7 @@ static int tmc_enable_etf_link(struct coresight_device *csdev,
return -EBUSY;
}
- if (atomic_read(&csdev->refcnt) == 0) {
+ if (csdev->refcnt == 0) {
ret = tmc_etf_enable_hw(drvdata);
if (!ret) {
local_set(&csdev->mode, CS_MODE_SYSFS);
@@ -379,7 +380,7 @@ static int tmc_enable_etf_link(struct coresight_device *csdev,
}
}
if (!ret)
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
spin_unlock_irqrestore(&drvdata->spinlock, flags);
if (first_enable)
@@ -401,7 +402,8 @@ static void tmc_disable_etf_link(struct coresight_device *csdev,
return;
}
- if (atomic_dec_return(&csdev->refcnt) == 0) {
+ csdev->refcnt--;
+ if (csdev->refcnt == 0) {
tmc_etf_disable_hw(drvdata);
local_set(&csdev->mode, CS_MODE_DISABLED);
last_disable = true;
@@ -489,7 +491,7 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev,
spin_lock_irqsave(&drvdata->spinlock, flags);
/* Don't do anything if another tracer is using this sink */
- if (atomic_read(&csdev->refcnt) != 1)
+ if (csdev->refcnt != 1)
goto out;
CS_UNLOCK(drvdata->base);
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 3dc989d4fcab..88a0fc375b4d 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1231,14 +1231,14 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
* touched, even if the buffer size has changed.
*/
if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
goto out;
}
ret = tmc_etr_enable_hw(drvdata, sysfs_buf);
if (!ret) {
local_set(&csdev->mode, CS_MODE_SYSFS);
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
}
out:
@@ -1564,7 +1564,7 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
spin_lock_irqsave(&drvdata->spinlock, flags);
/* Don't do anything if another tracer is using this sink */
- if (atomic_read(&csdev->refcnt) != 1) {
+ if (csdev->refcnt != 1) {
spin_unlock_irqrestore(&drvdata->spinlock, flags);
goto out;
}
@@ -1676,7 +1676,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
* use for this session.
*/
if (drvdata->pid == pid) {
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
goto unlock_out;
}
@@ -1686,7 +1686,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
drvdata->pid = pid;
local_set(&csdev->mode, CS_MODE_PERF);
drvdata->perf_buf = etr_perf->etr_buf;
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
}
unlock_out:
@@ -1719,7 +1719,8 @@ static int tmc_disable_etr_sink(struct coresight_device *csdev)
return -EBUSY;
}
- if (atomic_dec_return(&csdev->refcnt)) {
+ csdev->refcnt--;
+ if (csdev->refcnt) {
spin_unlock_irqrestore(&drvdata->spinlock, flags);
return -EBUSY;
}
diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
index 65c70995ab00..135a89654c4c 100644
--- a/drivers/hwtracing/coresight/coresight-tpda.c
+++ b/drivers/hwtracing/coresight/coresight-tpda.c
@@ -152,7 +152,8 @@ static int __tpda_enable(struct tpda_drvdata *drvdata, int port)
* Only do pre-port enable for first port that calls enable when the
* device's main refcount is still 0
*/
- if (!atomic_read(&drvdata->csdev->refcnt))
+ lockdep_assert_held(&drvdata->spinlock);
+ if (!drvdata->csdev->refcnt)
tpda_enable_pre_port(drvdata);
ret = tpda_enable_port(drvdata, port);
@@ -173,7 +174,7 @@ static int tpda_enable(struct coresight_device *csdev,
ret = __tpda_enable(drvdata, in->dest_port);
if (!ret) {
atomic_inc(&in->dest_refcnt);
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port);
}
}
@@ -204,7 +205,7 @@ static void tpda_disable(struct coresight_device *csdev,
spin_lock(&drvdata->spinlock);
if (atomic_dec_return(&in->dest_refcnt) == 0) {
__tpda_disable(drvdata, in->dest_port);
- atomic_dec(&csdev->refcnt);
+ csdev->refcnt--;
}
spin_unlock(&drvdata->spinlock);
diff --git a/drivers/hwtracing/coresight/coresight-tpiu.c b/drivers/hwtracing/coresight/coresight-tpiu.c
index 59eac93fd6bb..c23a6b9b41fe 100644
--- a/drivers/hwtracing/coresight/coresight-tpiu.c
+++ b/drivers/hwtracing/coresight/coresight-tpiu.c
@@ -58,6 +58,7 @@ struct tpiu_drvdata {
void __iomem *base;
struct clk *atclk;
struct coresight_device *csdev;
+ spinlock_t spinlock;
};
static void tpiu_enable_hw(struct csdev_access *csa)
@@ -72,8 +73,11 @@ static void tpiu_enable_hw(struct csdev_access *csa)
static int tpiu_enable(struct coresight_device *csdev, enum cs_mode mode,
void *__unused)
{
+ struct tpiu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ guard(spinlock)(&drvdata->spinlock);
tpiu_enable_hw(&csdev->access);
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
dev_dbg(&csdev->dev, "TPIU enabled\n");
return 0;
}
@@ -96,7 +100,11 @@ static void tpiu_disable_hw(struct csdev_access *csa)
static int tpiu_disable(struct coresight_device *csdev)
{
- if (atomic_dec_return(&csdev->refcnt))
+ struct tpiu_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
+
+ guard(spinlock)(&drvdata->spinlock);
+ csdev->refcnt--;
+ if (csdev->refcnt)
return -EBUSY;
tpiu_disable_hw(&csdev->access);
@@ -132,6 +140,8 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
if (!drvdata)
return -ENOMEM;
+ spin_lock_init(&drvdata->spinlock);
+
drvdata->atclk = devm_clk_get(&adev->dev, "atclk"); /* optional */
if (!IS_ERR(drvdata->atclk)) {
ret = clk_prepare_enable(drvdata->atclk);
diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.c b/drivers/hwtracing/coresight/ultrasoc-smb.c
index 1a8c64645b92..1146584a1745 100644
--- a/drivers/hwtracing/coresight/ultrasoc-smb.c
+++ b/drivers/hwtracing/coresight/ultrasoc-smb.c
@@ -103,7 +103,7 @@ static int smb_open(struct inode *inode, struct file *file)
if (drvdata->reading)
return -EBUSY;
- if (atomic_read(&drvdata->csdev->refcnt))
+ if (drvdata->csdev->refcnt)
return -EBUSY;
smb_update_data_size(drvdata);
@@ -271,7 +271,7 @@ static int smb_enable(struct coresight_device *csdev, enum cs_mode mode,
if (ret)
return ret;
- atomic_inc(&csdev->refcnt);
+ csdev->refcnt++;
dev_dbg(&csdev->dev, "Ultrasoc SMB enabled\n");
return ret;
@@ -286,7 +286,8 @@ static int smb_disable(struct coresight_device *csdev)
if (drvdata->reading)
return -EBUSY;
- if (atomic_dec_return(&csdev->refcnt))
+ csdev->refcnt--;
+ if (csdev->refcnt)
return -EBUSY;
/* Complain if we (somehow) got out of sync */
@@ -381,7 +382,7 @@ static unsigned long smb_update_buffer(struct coresight_device *csdev,
guard(spinlock)(&drvdata->spinlock);
/* Don't do anything if another tracer is using this sink. */
- if (atomic_read(&csdev->refcnt) != 1)
+ if (csdev->refcnt != 1)
return 0;
smb_disable_hw(drvdata);
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index e8dd0df98881..4400d554a16b 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -230,8 +230,15 @@ struct coresight_sysfs_link {
* actually an 'enum cs_mode', but is stored in an atomic type.
* This is always accessed through local_read() and local_set(),
* but wherever it's done from within the Coresight device's lock,
- * a non-atomic read would also work.
- * @refcnt: keep track of what is in use.
+ * a non-atomic read would also work. This is the main point of
+ * synchronisation between code happening inside the sysfs mode's
+ * coresight_mutex and outside when running in Perf mode. A compare
+ * and exchange swap is done to atomically claim one mode or the
+ * other.
+ * @refcnt: keep track of what is in use. Only access this outside of the
+ * device's spinlock when the coresight_mutex held and mode ==
+ * CS_MODE_SYSFS. Otherwise it must be accessed from inside the
+ * spinlock.
* @orphan: true if the component has connections that haven't been linked.
* @sysfs_sink_activated: 'true' when a sink has been selected for use via sysfs
* by writing a 1 to the 'enable_sink' file. A sink can be
@@ -257,7 +264,7 @@ struct coresight_device {
struct csdev_access access;
struct device dev;
local_t mode;
- atomic_t refcnt;
+ int refcnt;
bool orphan;
/* sink specific fields */
bool sysfs_sink_activated;
--
2.34.1
Most devices use mode, so move the mode definition out of the individual
devices and up to the Coresight device. This will allow the core code to
also know the mode which will be useful in a later commit.
This also fixes the inconsistency of the documentation of the mode field
on the individual device types. For example ETB10 had "this ETB is being
used".
Two devices didn't require an atomic mode type, so these usages have
been converted to atomic_get() and atomic_set() only to make it compile,
but the documentation of the field in struct coresight_device explains
this type of usage.
In the future, manipulation of the mode could be completely moved out of
the individual devices and into the core code because it's almost all
duplicate code, and this change is a step towards that.
Signed-off-by: James Clark <[email protected]>
---
drivers/hwtracing/coresight/coresight-etb10.c | 18 ++++++-------
drivers/hwtracing/coresight/coresight-etm.h | 2 --
.../coresight/coresight-etm3x-core.c | 13 +++++-----
.../coresight/coresight-etm3x-sysfs.c | 4 +--
drivers/hwtracing/coresight/coresight-stm.c | 20 +++++++-------
.../hwtracing/coresight/coresight-tmc-core.c | 2 +-
.../hwtracing/coresight/coresight-tmc-etf.c | 26 +++++++++----------
.../hwtracing/coresight/coresight-tmc-etr.c | 20 +++++++-------
drivers/hwtracing/coresight/coresight-tmc.h | 2 --
drivers/hwtracing/coresight/ultrasoc-smb.c | 13 +++++-----
drivers/hwtracing/coresight/ultrasoc-smb.h | 2 --
include/linux/coresight.h | 6 +++++
12 files changed, 62 insertions(+), 66 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index fa80039e0821..08e5bba862db 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c
@@ -76,7 +76,6 @@ DEFINE_CORESIGHT_DEVLIST(etb_devs, "etb");
* @pid: Process ID of the process being monitored by the session
* that is using this component.
* @buf: area of memory where ETB buffer content gets sent.
- * @mode: this ETB is being used.
* @buffer_depth: size of @buf.
* @trigger_cntr: amount of words to store after a trigger.
*/
@@ -89,7 +88,6 @@ struct etb_drvdata {
local_t reading;
pid_t pid;
u8 *buf;
- u32 mode;
u32 buffer_depth;
u32 trigger_cntr;
};
@@ -150,17 +148,17 @@ static int etb_enable_sysfs(struct coresight_device *csdev)
spin_lock_irqsave(&drvdata->spinlock, flags);
/* Don't messup with perf sessions. */
- if (drvdata->mode == CS_MODE_PERF) {
+ if (local_read(&csdev->mode) == CS_MODE_PERF) {
ret = -EBUSY;
goto out;
}
- if (drvdata->mode == CS_MODE_DISABLED) {
+ if (local_read(&csdev->mode) == CS_MODE_DISABLED) {
ret = etb_enable_hw(drvdata);
if (ret)
goto out;
- drvdata->mode = CS_MODE_SYSFS;
+ local_set(&csdev->mode, CS_MODE_SYSFS);
}
atomic_inc(&csdev->refcnt);
@@ -181,7 +179,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data)
spin_lock_irqsave(&drvdata->spinlock, flags);
/* No need to continue if the component is already in used by sysFS. */
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
ret = -EBUSY;
goto out;
}
@@ -216,7 +214,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data)
if (!ret) {
/* Associate with monitored process. */
drvdata->pid = pid;
- drvdata->mode = CS_MODE_PERF;
+ local_set(&drvdata->csdev->mode, CS_MODE_PERF);
atomic_inc(&csdev->refcnt);
}
@@ -362,11 +360,11 @@ static int etb_disable(struct coresight_device *csdev)
}
/* Complain if we (somehow) got out of sync */
- WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
+ WARN_ON_ONCE(local_read(&csdev->mode) == CS_MODE_DISABLED);
etb_disable_hw(drvdata);
/* Dissociate from monitored process. */
drvdata->pid = -1;
- drvdata->mode = CS_MODE_DISABLED;
+ local_set(&csdev->mode, CS_MODE_DISABLED);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
dev_dbg(&csdev->dev, "ETB disabled\n");
@@ -589,7 +587,7 @@ static void etb_dump(struct etb_drvdata *drvdata)
unsigned long flags;
spin_lock_irqsave(&drvdata->spinlock, flags);
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
__etb_disable_hw(drvdata);
etb_dump_hw(drvdata);
__etb_enable_hw(drvdata);
diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
index 9a0d08b092ae..e02c3ea972c9 100644
--- a/drivers/hwtracing/coresight/coresight-etm.h
+++ b/drivers/hwtracing/coresight/coresight-etm.h
@@ -215,7 +215,6 @@ struct etm_config {
* @port_size: port size as reported by ETMCR bit 4-6 and 21.
* @arch: ETM/PTM version number.
* @use_cpu14: true if management registers need to be accessed via CP14.
- * @mode: this tracer's mode, i.e sysFS, Perf or disabled.
* @sticky_enable: true if ETM base configuration has been done.
* @boot_enable:true if we should start tracing at boot time.
* @os_unlock: true if access to management registers is allowed.
@@ -238,7 +237,6 @@ struct etm_drvdata {
int port_size;
u8 arch;
bool use_cp14;
- local_t mode;
bool sticky_enable;
bool boot_enable;
bool os_unlock;
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
index 116a91d90ac2..29f62dfac673 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
@@ -559,7 +559,7 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
u32 val;
struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
- val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
+ val = local_cmpxchg(&drvdata->csdev->mode, CS_MODE_DISABLED, mode);
/* Someone is already using the tracer */
if (val)
@@ -578,7 +578,7 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
/* The tracer didn't start */
if (ret)
- local_set(&drvdata->mode, CS_MODE_DISABLED);
+ local_set(&drvdata->csdev->mode, CS_MODE_DISABLED);
return ret;
}
@@ -672,14 +672,13 @@ static void etm_disable(struct coresight_device *csdev,
struct perf_event *event)
{
enum cs_mode mode;
- struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
/*
* For as long as the tracer isn't disabled another entity can't
* change its status. As such we can read the status here without
* fearing it will change under us.
*/
- mode = local_read(&drvdata->mode);
+ mode = local_read(&csdev->mode);
switch (mode) {
case CS_MODE_DISABLED:
@@ -696,7 +695,7 @@ static void etm_disable(struct coresight_device *csdev,
}
if (mode)
- local_set(&drvdata->mode, CS_MODE_DISABLED);
+ local_set(&csdev->mode, CS_MODE_DISABLED);
}
static const struct coresight_ops_source etm_source_ops = {
@@ -730,7 +729,7 @@ static int etm_starting_cpu(unsigned int cpu)
etmdrvdata[cpu]->os_unlock = true;
}
- if (local_read(&etmdrvdata[cpu]->mode))
+ if (local_read(&etmdrvdata[cpu]->csdev->mode))
etm_enable_hw(etmdrvdata[cpu]);
spin_unlock(&etmdrvdata[cpu]->spinlock);
return 0;
@@ -742,7 +741,7 @@ static int etm_dying_cpu(unsigned int cpu)
return 0;
spin_lock(&etmdrvdata[cpu]->spinlock);
- if (local_read(&etmdrvdata[cpu]->mode))
+ if (local_read(&etmdrvdata[cpu]->csdev->mode))
etm_disable_hw(etmdrvdata[cpu]);
spin_unlock(&etmdrvdata[cpu]->spinlock);
return 0;
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
index 2f271b7fb048..6c8429c980b1 100644
--- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
+++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
@@ -722,7 +722,7 @@ static ssize_t cntr_val_show(struct device *dev,
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
struct etm_config *config = &drvdata->config;
- if (!local_read(&drvdata->mode)) {
+ if (!local_read(&drvdata->csdev->mode)) {
spin_lock(&drvdata->spinlock);
for (i = 0; i < drvdata->nr_cntr; i++)
ret += sprintf(buf, "counter %d: %x\n",
@@ -941,7 +941,7 @@ static ssize_t seq_curr_state_show(struct device *dev,
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
struct etm_config *config = &drvdata->config;
- if (!local_read(&drvdata->mode)) {
+ if (!local_read(&drvdata->csdev->mode)) {
val = config->seq_curr_state;
goto out;
}
diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
index a1c27c901ad1..190ba569b05a 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -119,7 +119,6 @@ DEFINE_CORESIGHT_DEVLIST(stm_devs, "stm");
* @spinlock: only one at a time pls.
* @chs: the channels accociated to this STM.
* @stm: structure associated to the generic STM interface.
- * @mode: this tracer's mode (enum cs_mode), i.e sysFS, or disabled.
* @traceid: value of the current ID for this component.
* @write_bytes: Maximus bytes this STM can write at a time.
* @stmsper: settings for register STMSPER.
@@ -136,7 +135,6 @@ struct stm_drvdata {
spinlock_t spinlock;
struct channel_space chs;
struct stm_data stm;
- local_t mode;
u8 traceid;
u32 write_bytes;
u32 stmsper;
@@ -201,7 +199,7 @@ static int stm_enable(struct coresight_device *csdev, struct perf_event *event,
if (mode != CS_MODE_SYSFS)
return -EINVAL;
- val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
+ val = local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, mode);
/* Someone is already using the tracer */
if (val)
@@ -266,7 +264,7 @@ static void stm_disable(struct coresight_device *csdev,
* change its status. As such we can read the status here without
* fearing it will change under us.
*/
- if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
+ if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
spin_lock(&drvdata->spinlock);
stm_disable_hw(drvdata);
spin_unlock(&drvdata->spinlock);
@@ -276,7 +274,7 @@ static void stm_disable(struct coresight_device *csdev,
pm_runtime_put(csdev->dev.parent);
- local_set(&drvdata->mode, CS_MODE_DISABLED);
+ local_set(&csdev->mode, CS_MODE_DISABLED);
dev_dbg(&csdev->dev, "STM tracing disabled\n");
}
}
@@ -373,7 +371,7 @@ static long stm_generic_set_options(struct stm_data *stm_data,
{
struct stm_drvdata *drvdata = container_of(stm_data,
struct stm_drvdata, stm);
- if (!(drvdata && local_read(&drvdata->mode)))
+ if (!(drvdata && local_read(&drvdata->csdev->mode)))
return -EINVAL;
if (channel >= drvdata->numsp)
@@ -408,7 +406,7 @@ static ssize_t notrace stm_generic_packet(struct stm_data *stm_data,
struct stm_drvdata, stm);
unsigned int stm_flags;
- if (!(drvdata && local_read(&drvdata->mode)))
+ if (!(drvdata && local_read(&drvdata->csdev->mode)))
return -EACCES;
if (channel >= drvdata->numsp)
@@ -515,7 +513,7 @@ static ssize_t port_select_show(struct device *dev,
struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
unsigned long val;
- if (!local_read(&drvdata->mode)) {
+ if (!local_read(&drvdata->csdev->mode)) {
val = drvdata->stmspscr;
} else {
spin_lock(&drvdata->spinlock);
@@ -541,7 +539,7 @@ static ssize_t port_select_store(struct device *dev,
spin_lock(&drvdata->spinlock);
drvdata->stmspscr = val;
- if (local_read(&drvdata->mode)) {
+ if (local_read(&drvdata->csdev->mode)) {
CS_UNLOCK(drvdata->base);
/* Process as per ARM's TRM recommendation */
stmsper = readl_relaxed(drvdata->base + STMSPER);
@@ -562,7 +560,7 @@ static ssize_t port_enable_show(struct device *dev,
struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
unsigned long val;
- if (!local_read(&drvdata->mode)) {
+ if (!local_read(&drvdata->csdev->mode)) {
val = drvdata->stmsper;
} else {
spin_lock(&drvdata->spinlock);
@@ -588,7 +586,7 @@ static ssize_t port_enable_store(struct device *dev,
spin_lock(&drvdata->spinlock);
drvdata->stmsper = val;
- if (local_read(&drvdata->mode)) {
+ if (local_read(&drvdata->csdev->mode)) {
CS_UNLOCK(drvdata->base);
writel_relaxed(drvdata->stmsper, drvdata->base + STMSPER);
CS_LOCK(drvdata->base);
diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
index 7ec5365e2b64..e5d47f61f9f3 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-core.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
@@ -558,7 +558,7 @@ static void tmc_shutdown(struct amba_device *adev)
spin_lock_irqsave(&drvdata->spinlock, flags);
- if (drvdata->mode == CS_MODE_DISABLED)
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_DISABLED)
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 7406b65e2cdd..2a7e516052a2 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
@@ -89,7 +89,7 @@ static void __tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
* When operating in sysFS mode the content of the buffer needs to be
* read before the TMC is disabled.
*/
- if (drvdata->mode == CS_MODE_SYSFS)
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS)
tmc_etb_dump_hw(drvdata);
tmc_disable_hw(drvdata);
@@ -205,7 +205,7 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
* sink is already enabled no memory is needed and the HW need not be
* touched.
*/
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
atomic_inc(&csdev->refcnt);
goto out;
}
@@ -228,7 +228,7 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
ret = tmc_etb_enable_hw(drvdata);
if (!ret) {
- drvdata->mode = CS_MODE_SYSFS;
+ local_set(&csdev->mode, CS_MODE_SYSFS);
atomic_inc(&csdev->refcnt);
} else {
/* Free up the buffer if we failed to enable */
@@ -262,7 +262,7 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
* No need to continue if the ETB/ETF is already operated
* from sysFS.
*/
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
ret = -EBUSY;
break;
}
@@ -292,7 +292,7 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
if (!ret) {
/* Associate with monitored process. */
drvdata->pid = pid;
- drvdata->mode = CS_MODE_PERF;
+ local_set(&csdev->mode, CS_MODE_PERF);
atomic_inc(&csdev->refcnt);
}
} while (0);
@@ -344,11 +344,11 @@ static int tmc_disable_etf_sink(struct coresight_device *csdev)
}
/* Complain if we (somehow) got out of sync */
- WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
+ WARN_ON_ONCE(local_read(&csdev->mode) == CS_MODE_DISABLED);
tmc_etb_disable_hw(drvdata);
/* Dissociate from monitored process. */
drvdata->pid = -1;
- drvdata->mode = CS_MODE_DISABLED;
+ local_set(&csdev->mode, CS_MODE_DISABLED);
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -374,7 +374,7 @@ static int tmc_enable_etf_link(struct coresight_device *csdev,
if (atomic_read(&csdev->refcnt) == 0) {
ret = tmc_etf_enable_hw(drvdata);
if (!ret) {
- drvdata->mode = CS_MODE_SYSFS;
+ local_set(&csdev->mode, CS_MODE_SYSFS);
first_enable = true;
}
}
@@ -403,7 +403,7 @@ static void tmc_disable_etf_link(struct coresight_device *csdev,
if (atomic_dec_return(&csdev->refcnt) == 0) {
tmc_etf_disable_hw(drvdata);
- drvdata->mode = CS_MODE_DISABLED;
+ local_set(&csdev->mode, CS_MODE_DISABLED);
last_disable = true;
}
spin_unlock_irqrestore(&drvdata->spinlock, flags);
@@ -483,7 +483,7 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev,
return 0;
/* This shouldn't happen */
- if (WARN_ON_ONCE(drvdata->mode != CS_MODE_PERF))
+ if (WARN_ON_ONCE(local_read(&csdev->mode) != CS_MODE_PERF))
return 0;
spin_lock_irqsave(&drvdata->spinlock, flags);
@@ -629,7 +629,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
}
/* Don't interfere if operated from Perf */
- if (drvdata->mode == CS_MODE_PERF) {
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_PERF) {
ret = -EINVAL;
goto out;
}
@@ -641,7 +641,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
}
/* Disable the TMC if need be */
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
/* There is no point in reading a TMC in HW FIFO mode */
mode = readl_relaxed(drvdata->base + TMC_MODE);
if (mode != TMC_MODE_CIRCULAR_BUFFER) {
@@ -673,7 +673,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
spin_lock_irqsave(&drvdata->spinlock, flags);
/* Re-enable the TMC if need be */
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
/* There is no point in reading a TMC in HW FIFO mode */
mode = readl_relaxed(drvdata->base + TMC_MODE);
if (mode != TMC_MODE_CIRCULAR_BUFFER) {
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index af02ba5d5f15..3dc989d4fcab 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1143,7 +1143,7 @@ static void __tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
* When operating in sysFS mode the content of the buffer needs to be
* read before the TMC is disabled.
*/
- if (drvdata->mode == CS_MODE_SYSFS)
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS)
tmc_etr_sync_sysfs_buf(drvdata);
tmc_disable_hw(drvdata);
@@ -1189,7 +1189,7 @@ static struct etr_buf *tmc_etr_get_sysfs_buffer(struct coresight_device *csdev)
spin_lock_irqsave(&drvdata->spinlock, flags);
}
- if (drvdata->reading || drvdata->mode == CS_MODE_PERF) {
+ if (drvdata->reading || local_read(&csdev->mode) == CS_MODE_PERF) {
ret = -EBUSY;
goto out;
}
@@ -1230,14 +1230,14 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
* sink is already enabled no memory is needed and the HW need not be
* touched, even if the buffer size has changed.
*/
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
atomic_inc(&csdev->refcnt);
goto out;
}
ret = tmc_etr_enable_hw(drvdata, sysfs_buf);
if (!ret) {
- drvdata->mode = CS_MODE_SYSFS;
+ local_set(&csdev->mode, CS_MODE_SYSFS);
atomic_inc(&csdev->refcnt);
}
@@ -1652,7 +1652,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
spin_lock_irqsave(&drvdata->spinlock, flags);
/* Don't use this sink if it is already claimed by sysFS */
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
rc = -EBUSY;
goto unlock_out;
}
@@ -1684,7 +1684,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
if (!rc) {
/* Associate with monitored process. */
drvdata->pid = pid;
- drvdata->mode = CS_MODE_PERF;
+ local_set(&csdev->mode, CS_MODE_PERF);
drvdata->perf_buf = etr_perf->etr_buf;
atomic_inc(&csdev->refcnt);
}
@@ -1725,11 +1725,11 @@ static int tmc_disable_etr_sink(struct coresight_device *csdev)
}
/* Complain if we (somehow) got out of sync */
- WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
+ WARN_ON_ONCE(local_read(&csdev->mode) == CS_MODE_DISABLED);
tmc_etr_disable_hw(drvdata);
/* Dissociate from monitored process. */
drvdata->pid = -1;
- drvdata->mode = CS_MODE_DISABLED;
+ local_set(&csdev->mode, CS_MODE_DISABLED);
/* Reset perf specific data */
drvdata->perf_buf = NULL;
@@ -1777,7 +1777,7 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
}
/* Disable the TMC if we are trying to read from a running session. */
- if (drvdata->mode == CS_MODE_SYSFS)
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS)
__tmc_etr_disable_hw(drvdata);
drvdata->reading = true;
@@ -1799,7 +1799,7 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
spin_lock_irqsave(&drvdata->spinlock, flags);
/* RE-enable the TMC if need be */
- if (drvdata->mode == CS_MODE_SYSFS) {
+ if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
/*
* The trace run will continue with the same allocated trace
* buffer. Since the tracer is still enabled drvdata::buf can't
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 8dcb426ac3e7..cef979c897e6 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -178,7 +178,6 @@ struct etr_buf {
* @size: trace buffer size for this TMC (common for all modes).
* @max_burst_size: The maximum burst size that can be initiated by
* TMC-ETR on AXI bus.
- * @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.
* @trigger_cntr: amount of words to store after a trigger.
@@ -203,7 +202,6 @@ struct tmc_drvdata {
u32 len;
u32 size;
u32 max_burst_size;
- u32 mode;
enum tmc_config_type config_type;
enum tmc_mem_intf_width memwidth;
u32 trigger_cntr;
diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.c b/drivers/hwtracing/coresight/ultrasoc-smb.c
index 10e886455b8b..1a8c64645b92 100644
--- a/drivers/hwtracing/coresight/ultrasoc-smb.c
+++ b/drivers/hwtracing/coresight/ultrasoc-smb.c
@@ -207,11 +207,11 @@ static void smb_enable_sysfs(struct coresight_device *csdev)
{
struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
- if (drvdata->mode != CS_MODE_DISABLED)
+ if (local_read(&csdev->mode) != CS_MODE_DISABLED)
return;
smb_enable_hw(drvdata);
- drvdata->mode = CS_MODE_SYSFS;
+ local_set(&csdev->mode, CS_MODE_SYSFS);
}
static int smb_enable_perf(struct coresight_device *csdev, void *data)
@@ -234,7 +234,7 @@ static int smb_enable_perf(struct coresight_device *csdev, void *data)
if (drvdata->pid == -1) {
smb_enable_hw(drvdata);
drvdata->pid = pid;
- drvdata->mode = CS_MODE_PERF;
+ local_set(&csdev->mode, CS_MODE_PERF);
}
return 0;
@@ -253,7 +253,8 @@ static int smb_enable(struct coresight_device *csdev, enum cs_mode mode,
return -EBUSY;
/* Do nothing, the SMB is already enabled as other mode */
- if (drvdata->mode != CS_MODE_DISABLED && drvdata->mode != mode)
+ if (local_read(&csdev->mode) != CS_MODE_DISABLED &&
+ local_read(&csdev->mode) != mode)
return -EBUSY;
switch (mode) {
@@ -289,13 +290,13 @@ static int smb_disable(struct coresight_device *csdev)
return -EBUSY;
/* Complain if we (somehow) got out of sync */
- WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
+ WARN_ON_ONCE(local_read(&csdev->mode) == CS_MODE_DISABLED);
smb_disable_hw(drvdata);
/* Dissociate from the target process. */
drvdata->pid = -1;
- drvdata->mode = CS_MODE_DISABLED;
+ local_set(&csdev->mode, CS_MODE_DISABLED);
dev_dbg(&csdev->dev, "Ultrasoc SMB disabled\n");
return 0;
diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.h b/drivers/hwtracing/coresight/ultrasoc-smb.h
index 82a44c14a882..a91d39cfccb8 100644
--- a/drivers/hwtracing/coresight/ultrasoc-smb.h
+++ b/drivers/hwtracing/coresight/ultrasoc-smb.h
@@ -109,7 +109,6 @@ struct smb_data_buffer {
* @reading: Synchronise user space access to SMB buffer.
* @pid: Process ID of the process being monitored by the
* session that is using this component.
- * @mode: How this SMB is being used, perf mode or sysfs mode.
*/
struct smb_drv_data {
void __iomem *base;
@@ -119,7 +118,6 @@ struct smb_drv_data {
spinlock_t spinlock;
bool reading;
pid_t pid;
- enum cs_mode mode;
};
#endif
diff --git a/include/linux/coresight.h b/include/linux/coresight.h
index 65131bfbd904..ba817f563ff7 100644
--- a/include/linux/coresight.h
+++ b/include/linux/coresight.h
@@ -226,6 +226,11 @@ struct coresight_sysfs_link {
* by @coresight_ops.
* @access: Device i/o access abstraction for this device.
* @dev: The device entity associated to this component.
+ * @mode: This tracer's mode, i.e sysFS, Perf or disabled. This is
+ * actually an 'enum cs_mode', but is stored in an atomic type.
+ * This is always accessed through local_read() and local_set(),
+ * but wherever it's done from within the Coresight device's lock,
+ * a non-atomic read would also work.
* @refcnt: keep track of what is in use.
* @orphan: true if the component has connections that haven't been linked.
* @enable: 'true' if component is currently part of an active path.
@@ -252,6 +257,7 @@ struct coresight_device {
const struct coresight_ops *ops;
struct csdev_access access;
struct device dev;
+ local_t mode;
atomic_t refcnt;
bool orphan;
bool enable;
--
2.34.1
On 12/12/2023 15:54, James Clark wrote:
> Most devices use mode, so move the mode definition out of the individual
> devices and up to the Coresight device. This will allow the core code to
> also know the mode which will be useful in a later commit.
>
> This also fixes the inconsistency of the documentation of the mode field
> on the individual device types. For example ETB10 had "this ETB is being
> used".
>
> Two devices didn't require an atomic mode type, so these usages have
> been converted to atomic_get() and atomic_set() only to make it compile,
> but the documentation of the field in struct coresight_device explains
> this type of usage.
>
> In the future, manipulation of the mode could be completely moved out of
> the individual devices and into the core code because it's almost all
> duplicate code, and this change is a step towards that.
The change looks good to me. I am wondering if we should abstract it out ?
i.e.,
csdev_get_mode(struct coresight_device *csdev)
csdev_set_mode(struct coresight_device *csdev, mode)
csdev_{cmpxchg or set_if}_mode(csdev, old_mode, new_mode)
>
> Signed-off-by: James Clark <[email protected]>
> ---
> drivers/hwtracing/coresight/coresight-etb10.c | 18 ++++++-------
> drivers/hwtracing/coresight/coresight-etm.h | 2 --
> .../coresight/coresight-etm3x-core.c | 13 +++++-----
> .../coresight/coresight-etm3x-sysfs.c | 4 +--
> drivers/hwtracing/coresight/coresight-stm.c | 20 +++++++-------
> .../hwtracing/coresight/coresight-tmc-core.c | 2 +-
> .../hwtracing/coresight/coresight-tmc-etf.c | 26 +++++++++----------
> .../hwtracing/coresight/coresight-tmc-etr.c | 20 +++++++-------
> drivers/hwtracing/coresight/coresight-tmc.h | 2 --
> drivers/hwtracing/coresight/ultrasoc-smb.c | 13 +++++-----
> drivers/hwtracing/coresight/ultrasoc-smb.h | 2 --
> include/linux/coresight.h | 6 +++++
> 12 files changed, 62 insertions(+), 66 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
> index fa80039e0821..08e5bba862db 100644
> --- a/drivers/hwtracing/coresight/coresight-etb10.c
> +++ b/drivers/hwtracing/coresight/coresight-etb10.c
> @@ -76,7 +76,6 @@ DEFINE_CORESIGHT_DEVLIST(etb_devs, "etb");
> * @pid: Process ID of the process being monitored by the session
> * that is using this component.
> * @buf: area of memory where ETB buffer content gets sent.
> - * @mode: this ETB is being used.
> * @buffer_depth: size of @buf.
> * @trigger_cntr: amount of words to store after a trigger.
> */
> @@ -89,7 +88,6 @@ struct etb_drvdata {
> local_t reading;
> pid_t pid;
> u8 *buf;
> - u32 mode;
> u32 buffer_depth;
> u32 trigger_cntr;
> };
> @@ -150,17 +148,17 @@ static int etb_enable_sysfs(struct coresight_device *csdev)
> spin_lock_irqsave(&drvdata->spinlock, flags);
>
> /* Don't messup with perf sessions. */
> - if (drvdata->mode == CS_MODE_PERF) {
> + if (local_read(&csdev->mode) == CS_MODE_PERF) {
> ret = -EBUSY;
> goto out;
> }
>
> - if (drvdata->mode == CS_MODE_DISABLED) {
> + if (local_read(&csdev->mode) == CS_MODE_DISABLED) {
> ret = etb_enable_hw(drvdata);
> if (ret)
> goto out;
>
> - drvdata->mode = CS_MODE_SYSFS;
> + local_set(&csdev->mode, CS_MODE_SYSFS);
> }
>
> atomic_inc(&csdev->refcnt);
> @@ -181,7 +179,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data)
> spin_lock_irqsave(&drvdata->spinlock, flags);
>
> /* No need to continue if the component is already in used by sysFS. */
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
> ret = -EBUSY;
> goto out;
> }
> @@ -216,7 +214,7 @@ static int etb_enable_perf(struct coresight_device *csdev, void *data)
> if (!ret) {
> /* Associate with monitored process. */
> drvdata->pid = pid;
> - drvdata->mode = CS_MODE_PERF;
> + local_set(&drvdata->csdev->mode, CS_MODE_PERF);
> atomic_inc(&csdev->refcnt);
> }
>
> @@ -362,11 +360,11 @@ static int etb_disable(struct coresight_device *csdev)
> }
>
> /* Complain if we (somehow) got out of sync */
> - WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
> + WARN_ON_ONCE(local_read(&csdev->mode) == CS_MODE_DISABLED);
> etb_disable_hw(drvdata);
> /* Dissociate from monitored process. */
> drvdata->pid = -1;
> - drvdata->mode = CS_MODE_DISABLED;
> + local_set(&csdev->mode, CS_MODE_DISABLED);
> spin_unlock_irqrestore(&drvdata->spinlock, flags);
>
> dev_dbg(&csdev->dev, "ETB disabled\n");
> @@ -589,7 +587,7 @@ static void etb_dump(struct etb_drvdata *drvdata)
> unsigned long flags;
>
> spin_lock_irqsave(&drvdata->spinlock, flags);
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
> __etb_disable_hw(drvdata);
> etb_dump_hw(drvdata);
> __etb_enable_hw(drvdata);
> diff --git a/drivers/hwtracing/coresight/coresight-etm.h b/drivers/hwtracing/coresight/coresight-etm.h
> index 9a0d08b092ae..e02c3ea972c9 100644
> --- a/drivers/hwtracing/coresight/coresight-etm.h
> +++ b/drivers/hwtracing/coresight/coresight-etm.h
> @@ -215,7 +215,6 @@ struct etm_config {
> * @port_size: port size as reported by ETMCR bit 4-6 and 21.
> * @arch: ETM/PTM version number.
> * @use_cpu14: true if management registers need to be accessed via CP14.
> - * @mode: this tracer's mode, i.e sysFS, Perf or disabled.
> * @sticky_enable: true if ETM base configuration has been done.
> * @boot_enable:true if we should start tracing at boot time.
> * @os_unlock: true if access to management registers is allowed.
> @@ -238,7 +237,6 @@ struct etm_drvdata {
> int port_size;
> u8 arch;
> bool use_cp14;
> - local_t mode;
> bool sticky_enable;
> bool boot_enable;
> bool os_unlock;
> diff --git a/drivers/hwtracing/coresight/coresight-etm3x-core.c b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> index 116a91d90ac2..29f62dfac673 100644
> --- a/drivers/hwtracing/coresight/coresight-etm3x-core.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x-core.c
> @@ -559,7 +559,7 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
> u32 val;
> struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>
> - val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
> + val = local_cmpxchg(&drvdata->csdev->mode, CS_MODE_DISABLED, mode);
>
> /* Someone is already using the tracer */
> if (val)
> @@ -578,7 +578,7 @@ static int etm_enable(struct coresight_device *csdev, struct perf_event *event,
>
> /* The tracer didn't start */
> if (ret)
> - local_set(&drvdata->mode, CS_MODE_DISABLED);
> + local_set(&drvdata->csdev->mode, CS_MODE_DISABLED);
>
> return ret;
> }
> @@ -672,14 +672,13 @@ static void etm_disable(struct coresight_device *csdev,
> struct perf_event *event)
> {
> enum cs_mode mode;
> - struct etm_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>
> /*
> * For as long as the tracer isn't disabled another entity can't
> * change its status. As such we can read the status here without
> * fearing it will change under us.
> */
> - mode = local_read(&drvdata->mode);
> + mode = local_read(&csdev->mode);
>
> switch (mode) {
> case CS_MODE_DISABLED:
> @@ -696,7 +695,7 @@ static void etm_disable(struct coresight_device *csdev,
> }
>
> if (mode)
> - local_set(&drvdata->mode, CS_MODE_DISABLED);
> + local_set(&csdev->mode, CS_MODE_DISABLED);
> }
>
> static const struct coresight_ops_source etm_source_ops = {
> @@ -730,7 +729,7 @@ static int etm_starting_cpu(unsigned int cpu)
> etmdrvdata[cpu]->os_unlock = true;
> }
>
> - if (local_read(&etmdrvdata[cpu]->mode))
> + if (local_read(&etmdrvdata[cpu]->csdev->mode))
> etm_enable_hw(etmdrvdata[cpu]);
> spin_unlock(&etmdrvdata[cpu]->spinlock);
> return 0;
> @@ -742,7 +741,7 @@ static int etm_dying_cpu(unsigned int cpu)
> return 0;
>
> spin_lock(&etmdrvdata[cpu]->spinlock);
> - if (local_read(&etmdrvdata[cpu]->mode))
> + if (local_read(&etmdrvdata[cpu]->csdev->mode))
> etm_disable_hw(etmdrvdata[cpu]);
> spin_unlock(&etmdrvdata[cpu]->spinlock);
> return 0;
> diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
> index 2f271b7fb048..6c8429c980b1 100644
> --- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c
> @@ -722,7 +722,7 @@ static ssize_t cntr_val_show(struct device *dev,
> struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> struct etm_config *config = &drvdata->config;
>
> - if (!local_read(&drvdata->mode)) {
> + if (!local_read(&drvdata->csdev->mode)) {
> spin_lock(&drvdata->spinlock);
> for (i = 0; i < drvdata->nr_cntr; i++)
> ret += sprintf(buf, "counter %d: %x\n",
> @@ -941,7 +941,7 @@ static ssize_t seq_curr_state_show(struct device *dev,
> struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> struct etm_config *config = &drvdata->config;
>
> - if (!local_read(&drvdata->mode)) {
> + if (!local_read(&drvdata->csdev->mode)) {
> val = config->seq_curr_state;
> goto out;
> }
> diff --git a/drivers/hwtracing/coresight/coresight-stm.c b/drivers/hwtracing/coresight/coresight-stm.c
> index a1c27c901ad1..190ba569b05a 100644
> --- a/drivers/hwtracing/coresight/coresight-stm.c
> +++ b/drivers/hwtracing/coresight/coresight-stm.c
> @@ -119,7 +119,6 @@ DEFINE_CORESIGHT_DEVLIST(stm_devs, "stm");
> * @spinlock: only one at a time pls.
> * @chs: the channels accociated to this STM.
> * @stm: structure associated to the generic STM interface.
> - * @mode: this tracer's mode (enum cs_mode), i.e sysFS, or disabled.
> * @traceid: value of the current ID for this component.
> * @write_bytes: Maximus bytes this STM can write at a time.
> * @stmsper: settings for register STMSPER.
> @@ -136,7 +135,6 @@ struct stm_drvdata {
> spinlock_t spinlock;
> struct channel_space chs;
> struct stm_data stm;
> - local_t mode;
> u8 traceid;
> u32 write_bytes;
> u32 stmsper;
> @@ -201,7 +199,7 @@ static int stm_enable(struct coresight_device *csdev, struct perf_event *event,
> if (mode != CS_MODE_SYSFS)
> return -EINVAL;
>
> - val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);
> + val = local_cmpxchg(&csdev->mode, CS_MODE_DISABLED, mode);
>
> /* Someone is already using the tracer */
> if (val)
> @@ -266,7 +264,7 @@ static void stm_disable(struct coresight_device *csdev,
> * change its status. As such we can read the status here without
> * fearing it will change under us.
> */
> - if (local_read(&drvdata->mode) == CS_MODE_SYSFS) {
> + if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
> spin_lock(&drvdata->spinlock);
> stm_disable_hw(drvdata);
> spin_unlock(&drvdata->spinlock);
> @@ -276,7 +274,7 @@ static void stm_disable(struct coresight_device *csdev,
>
> pm_runtime_put(csdev->dev.parent);
>
> - local_set(&drvdata->mode, CS_MODE_DISABLED);
> + local_set(&csdev->mode, CS_MODE_DISABLED);
> dev_dbg(&csdev->dev, "STM tracing disabled\n");
> }
> }
> @@ -373,7 +371,7 @@ static long stm_generic_set_options(struct stm_data *stm_data,
> {
> struct stm_drvdata *drvdata = container_of(stm_data,
> struct stm_drvdata, stm);
> - if (!(drvdata && local_read(&drvdata->mode)))
> + if (!(drvdata && local_read(&drvdata->csdev->mode)))
> return -EINVAL;
>
> if (channel >= drvdata->numsp)
> @@ -408,7 +406,7 @@ static ssize_t notrace stm_generic_packet(struct stm_data *stm_data,
> struct stm_drvdata, stm);
> unsigned int stm_flags;
>
> - if (!(drvdata && local_read(&drvdata->mode)))
> + if (!(drvdata && local_read(&drvdata->csdev->mode)))
> return -EACCES;
>
> if (channel >= drvdata->numsp)
> @@ -515,7 +513,7 @@ static ssize_t port_select_show(struct device *dev,
> struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> unsigned long val;
>
> - if (!local_read(&drvdata->mode)) {
> + if (!local_read(&drvdata->csdev->mode)) {
> val = drvdata->stmspscr;
> } else {
> spin_lock(&drvdata->spinlock);
> @@ -541,7 +539,7 @@ static ssize_t port_select_store(struct device *dev,
> spin_lock(&drvdata->spinlock);
> drvdata->stmspscr = val;
>
> - if (local_read(&drvdata->mode)) {
> + if (local_read(&drvdata->csdev->mode)) {
> CS_UNLOCK(drvdata->base);
> /* Process as per ARM's TRM recommendation */
> stmsper = readl_relaxed(drvdata->base + STMSPER);
> @@ -562,7 +560,7 @@ static ssize_t port_enable_show(struct device *dev,
> struct stm_drvdata *drvdata = dev_get_drvdata(dev->parent);
> unsigned long val;
>
> - if (!local_read(&drvdata->mode)) {
> + if (!local_read(&drvdata->csdev->mode)) {
> val = drvdata->stmsper;
> } else {
> spin_lock(&drvdata->spinlock);
> @@ -588,7 +586,7 @@ static ssize_t port_enable_store(struct device *dev,
> spin_lock(&drvdata->spinlock);
> drvdata->stmsper = val;
>
> - if (local_read(&drvdata->mode)) {
> + if (local_read(&drvdata->csdev->mode)) {
> CS_UNLOCK(drvdata->base);
> writel_relaxed(drvdata->stmsper, drvdata->base + STMSPER);
> CS_LOCK(drvdata->base);
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-core.c b/drivers/hwtracing/coresight/coresight-tmc-core.c
> index 7ec5365e2b64..e5d47f61f9f3 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-core.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-core.c
> @@ -558,7 +558,7 @@ static void tmc_shutdown(struct amba_device *adev)
>
> spin_lock_irqsave(&drvdata->spinlock, flags);
>
> - if (drvdata->mode == CS_MODE_DISABLED)
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_DISABLED)
> 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 7406b65e2cdd..2a7e516052a2 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c
> @@ -89,7 +89,7 @@ static void __tmc_etb_disable_hw(struct tmc_drvdata *drvdata)
> * When operating in sysFS mode the content of the buffer needs to be
> * read before the TMC is disabled.
> */
> - if (drvdata->mode == CS_MODE_SYSFS)
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS)
> tmc_etb_dump_hw(drvdata);
> tmc_disable_hw(drvdata);
>
> @@ -205,7 +205,7 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
> * sink is already enabled no memory is needed and the HW need not be
> * touched.
> */
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
> atomic_inc(&csdev->refcnt);
> goto out;
> }
> @@ -228,7 +228,7 @@ static int tmc_enable_etf_sink_sysfs(struct coresight_device *csdev)
>
> ret = tmc_etb_enable_hw(drvdata);
> if (!ret) {
> - drvdata->mode = CS_MODE_SYSFS;
> + local_set(&csdev->mode, CS_MODE_SYSFS);
> atomic_inc(&csdev->refcnt);
> } else {
> /* Free up the buffer if we failed to enable */
> @@ -262,7 +262,7 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
> * No need to continue if the ETB/ETF is already operated
> * from sysFS.
> */
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
> ret = -EBUSY;
> break;
> }
> @@ -292,7 +292,7 @@ static int tmc_enable_etf_sink_perf(struct coresight_device *csdev, void *data)
> if (!ret) {
> /* Associate with monitored process. */
> drvdata->pid = pid;
> - drvdata->mode = CS_MODE_PERF;
> + local_set(&csdev->mode, CS_MODE_PERF);
> atomic_inc(&csdev->refcnt);
> }
> } while (0);
> @@ -344,11 +344,11 @@ static int tmc_disable_etf_sink(struct coresight_device *csdev)
> }
>
> /* Complain if we (somehow) got out of sync */
> - WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
> + WARN_ON_ONCE(local_read(&csdev->mode) == CS_MODE_DISABLED);
> tmc_etb_disable_hw(drvdata);
> /* Dissociate from monitored process. */
> drvdata->pid = -1;
> - drvdata->mode = CS_MODE_DISABLED;
> + local_set(&csdev->mode, CS_MODE_DISABLED);
>
> spin_unlock_irqrestore(&drvdata->spinlock, flags);
>
> @@ -374,7 +374,7 @@ static int tmc_enable_etf_link(struct coresight_device *csdev,
> if (atomic_read(&csdev->refcnt) == 0) {
> ret = tmc_etf_enable_hw(drvdata);
> if (!ret) {
> - drvdata->mode = CS_MODE_SYSFS;
> + local_set(&csdev->mode, CS_MODE_SYSFS);
> first_enable = true;
> }
> }
> @@ -403,7 +403,7 @@ static void tmc_disable_etf_link(struct coresight_device *csdev,
>
> if (atomic_dec_return(&csdev->refcnt) == 0) {
> tmc_etf_disable_hw(drvdata);
> - drvdata->mode = CS_MODE_DISABLED;
> + local_set(&csdev->mode, CS_MODE_DISABLED);
> last_disable = true;
> }
> spin_unlock_irqrestore(&drvdata->spinlock, flags);
> @@ -483,7 +483,7 @@ static unsigned long tmc_update_etf_buffer(struct coresight_device *csdev,
> return 0;
>
> /* This shouldn't happen */
> - if (WARN_ON_ONCE(drvdata->mode != CS_MODE_PERF))
> + if (WARN_ON_ONCE(local_read(&csdev->mode) != CS_MODE_PERF))
> return 0;
>
> spin_lock_irqsave(&drvdata->spinlock, flags);
> @@ -629,7 +629,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
> }
>
> /* Don't interfere if operated from Perf */
> - if (drvdata->mode == CS_MODE_PERF) {
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_PERF) {
> ret = -EINVAL;
> goto out;
> }
> @@ -641,7 +641,7 @@ int tmc_read_prepare_etb(struct tmc_drvdata *drvdata)
> }
>
> /* Disable the TMC if need be */
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
> /* There is no point in reading a TMC in HW FIFO mode */
> mode = readl_relaxed(drvdata->base + TMC_MODE);
> if (mode != TMC_MODE_CIRCULAR_BUFFER) {
> @@ -673,7 +673,7 @@ int tmc_read_unprepare_etb(struct tmc_drvdata *drvdata)
> spin_lock_irqsave(&drvdata->spinlock, flags);
>
> /* Re-enable the TMC if need be */
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
> /* There is no point in reading a TMC in HW FIFO mode */
> mode = readl_relaxed(drvdata->base + TMC_MODE);
> if (mode != TMC_MODE_CIRCULAR_BUFFER) {
> diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> index af02ba5d5f15..3dc989d4fcab 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
> @@ -1143,7 +1143,7 @@ static void __tmc_etr_disable_hw(struct tmc_drvdata *drvdata)
> * When operating in sysFS mode the content of the buffer needs to be
> * read before the TMC is disabled.
> */
> - if (drvdata->mode == CS_MODE_SYSFS)
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS)
> tmc_etr_sync_sysfs_buf(drvdata);
>
> tmc_disable_hw(drvdata);
> @@ -1189,7 +1189,7 @@ static struct etr_buf *tmc_etr_get_sysfs_buffer(struct coresight_device *csdev)
> spin_lock_irqsave(&drvdata->spinlock, flags);
> }
>
> - if (drvdata->reading || drvdata->mode == CS_MODE_PERF) {
> + if (drvdata->reading || local_read(&csdev->mode) == CS_MODE_PERF) {
> ret = -EBUSY;
> goto out;
> }
> @@ -1230,14 +1230,14 @@ static int tmc_enable_etr_sink_sysfs(struct coresight_device *csdev)
> * sink is already enabled no memory is needed and the HW need not be
> * touched, even if the buffer size has changed.
> */
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
> atomic_inc(&csdev->refcnt);
> goto out;
> }
>
> ret = tmc_etr_enable_hw(drvdata, sysfs_buf);
> if (!ret) {
> - drvdata->mode = CS_MODE_SYSFS;
> + local_set(&csdev->mode, CS_MODE_SYSFS);
> atomic_inc(&csdev->refcnt);
> }
>
> @@ -1652,7 +1652,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
>
> spin_lock_irqsave(&drvdata->spinlock, flags);
> /* Don't use this sink if it is already claimed by sysFS */
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
> rc = -EBUSY;
> goto unlock_out;
> }
> @@ -1684,7 +1684,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
> if (!rc) {
> /* Associate with monitored process. */
> drvdata->pid = pid;
> - drvdata->mode = CS_MODE_PERF;
> + local_set(&csdev->mode, CS_MODE_PERF);
> drvdata->perf_buf = etr_perf->etr_buf;
> atomic_inc(&csdev->refcnt);
> }
> @@ -1725,11 +1725,11 @@ static int tmc_disable_etr_sink(struct coresight_device *csdev)
> }
>
> /* Complain if we (somehow) got out of sync */
> - WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
> + WARN_ON_ONCE(local_read(&csdev->mode) == CS_MODE_DISABLED);
> tmc_etr_disable_hw(drvdata);
> /* Dissociate from monitored process. */
> drvdata->pid = -1;
> - drvdata->mode = CS_MODE_DISABLED;
> + local_set(&csdev->mode, CS_MODE_DISABLED);
> /* Reset perf specific data */
> drvdata->perf_buf = NULL;
>
> @@ -1777,7 +1777,7 @@ int tmc_read_prepare_etr(struct tmc_drvdata *drvdata)
> }
>
> /* Disable the TMC if we are trying to read from a running session. */
> - if (drvdata->mode == CS_MODE_SYSFS)
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS)
> __tmc_etr_disable_hw(drvdata);
>
> drvdata->reading = true;
> @@ -1799,7 +1799,7 @@ int tmc_read_unprepare_etr(struct tmc_drvdata *drvdata)
> spin_lock_irqsave(&drvdata->spinlock, flags);
>
> /* RE-enable the TMC if need be */
> - if (drvdata->mode == CS_MODE_SYSFS) {
> + if (local_read(&drvdata->csdev->mode) == CS_MODE_SYSFS) {
> /*
> * The trace run will continue with the same allocated trace
> * buffer. Since the tracer is still enabled drvdata::buf can't
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
> index 8dcb426ac3e7..cef979c897e6 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.h
> +++ b/drivers/hwtracing/coresight/coresight-tmc.h
> @@ -178,7 +178,6 @@ struct etr_buf {
> * @size: trace buffer size for this TMC (common for all modes).
> * @max_burst_size: The maximum burst size that can be initiated by
> * TMC-ETR on AXI bus.
> - * @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.
> * @trigger_cntr: amount of words to store after a trigger.
> @@ -203,7 +202,6 @@ struct tmc_drvdata {
> u32 len;
> u32 size;
> u32 max_burst_size;
> - u32 mode;
> enum tmc_config_type config_type;
> enum tmc_mem_intf_width memwidth;
> u32 trigger_cntr;
> diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.c b/drivers/hwtracing/coresight/ultrasoc-smb.c
> index 10e886455b8b..1a8c64645b92 100644
> --- a/drivers/hwtracing/coresight/ultrasoc-smb.c
> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.c
> @@ -207,11 +207,11 @@ static void smb_enable_sysfs(struct coresight_device *csdev)
> {
> struct smb_drv_data *drvdata = dev_get_drvdata(csdev->dev.parent);
>
> - if (drvdata->mode != CS_MODE_DISABLED)
> + if (local_read(&csdev->mode) != CS_MODE_DISABLED)
> return;
>
> smb_enable_hw(drvdata);
> - drvdata->mode = CS_MODE_SYSFS;
> + local_set(&csdev->mode, CS_MODE_SYSFS);
> }
>
> static int smb_enable_perf(struct coresight_device *csdev, void *data)
> @@ -234,7 +234,7 @@ static int smb_enable_perf(struct coresight_device *csdev, void *data)
> if (drvdata->pid == -1) {
> smb_enable_hw(drvdata);
> drvdata->pid = pid;
> - drvdata->mode = CS_MODE_PERF;
> + local_set(&csdev->mode, CS_MODE_PERF);
> }
>
> return 0;
> @@ -253,7 +253,8 @@ static int smb_enable(struct coresight_device *csdev, enum cs_mode mode,
> return -EBUSY;
>
> /* Do nothing, the SMB is already enabled as other mode */
> - if (drvdata->mode != CS_MODE_DISABLED && drvdata->mode != mode)
> + if (local_read(&csdev->mode) != CS_MODE_DISABLED &&
> + local_read(&csdev->mode) != mode)
> return -EBUSY;
>
> switch (mode) {
> @@ -289,13 +290,13 @@ static int smb_disable(struct coresight_device *csdev)
> return -EBUSY;
>
> /* Complain if we (somehow) got out of sync */
> - WARN_ON_ONCE(drvdata->mode == CS_MODE_DISABLED);
> + WARN_ON_ONCE(local_read(&csdev->mode) == CS_MODE_DISABLED);
>
> smb_disable_hw(drvdata);
>
> /* Dissociate from the target process. */
> drvdata->pid = -1;
> - drvdata->mode = CS_MODE_DISABLED;
> + local_set(&csdev->mode, CS_MODE_DISABLED);
> dev_dbg(&csdev->dev, "Ultrasoc SMB disabled\n");
>
> return 0;
> diff --git a/drivers/hwtracing/coresight/ultrasoc-smb.h b/drivers/hwtracing/coresight/ultrasoc-smb.h
> index 82a44c14a882..a91d39cfccb8 100644
> --- a/drivers/hwtracing/coresight/ultrasoc-smb.h
> +++ b/drivers/hwtracing/coresight/ultrasoc-smb.h
> @@ -109,7 +109,6 @@ struct smb_data_buffer {
> * @reading: Synchronise user space access to SMB buffer.
> * @pid: Process ID of the process being monitored by the
> * session that is using this component.
> - * @mode: How this SMB is being used, perf mode or sysfs mode.
> */
> struct smb_drv_data {
> void __iomem *base;
> @@ -119,7 +118,6 @@ struct smb_drv_data {
> spinlock_t spinlock;
> bool reading;
> pid_t pid;
> - enum cs_mode mode;
> };
>
> #endif
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 65131bfbd904..ba817f563ff7 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -226,6 +226,11 @@ struct coresight_sysfs_link {
> * by @coresight_ops.
> * @access: Device i/o access abstraction for this device.
> * @dev: The device entity associated to this component.
> + * @mode: This tracer's mode, i.e sysFS, Perf or disabled. This is
> + * actually an 'enum cs_mode', but is stored in an atomic type.
> + * This is always accessed through local_read() and local_set(),
> + * but wherever it's done from within the Coresight device's lock,
> + * a non-atomic read would also work.
By abstracting it, we could enforce this change. Eitherways, the change
as such is fine by me.
Suzuki
> * @refcnt: keep track of what is in use.
> * @orphan: true if the component has connections that haven't been linked.
> * @enable: 'true' if component is currently part of an active path.
> @@ -252,6 +257,7 @@ struct coresight_device {
> const struct coresight_ops *ops;
> struct csdev_access access;
> struct device dev;
> + local_t mode;
> atomic_t refcnt;
> bool orphan;
> bool enable;
Hi James
+Cc: Tao Zhang <[email protected]>
+Cc: Mao Jinlong <[email protected]>
On 12/12/2023 15:54, James Clark wrote:
> 'enable', which probably should have been 'enabled', is only ever read
> in the core code in relation to controlling sources, and specifically
> only sources in sysfs mode. Confusingly it's not labelled as such and
> relying on it can be a source of bugs like the one fixed by
> commit 078dbba3f0c9 ("coresight: Fix crash when Perf and sysfs modes are
> used concurrently").
>
> Most importantly, it can only be used when the coresight_mutex is held
> which is only done when enabling and disabling paths in sysfs mode, and
> not Perf mode.
I think we may be able to relax this a bit for the syfs. The sole reason
for holding the mutex is for the "build_path" (and get_enabled_sink)
where we need to make sure that no devices are removed/added. We hold
necessary refcount on the device and the module (via
coresight_grab_device()). After which, we should be able to release the
mutex and perform the rest without it in coresight_enable()
> So to prevent its usage spreading and leaking out to
> other devices, remove it.
>
> It's use is equivalent to checking if the mode is currently sysfs, as
> due to the coresight_mutex lock, mode == CS_MODE_SYSFS can only become
> true or untrue when that lock is held, and when mode == CS_MODE_SYSFS
> the device is both enabled and in sysfs mode.
All of the above makes sense and looks good to me.
>
> The one place it was used outside of the core code is in TPDA, but that
> pattern is more appropriately represented using refcounts inside the
> device's own spinlock.
But, I think we can clean up this code a bit more better. See below.
>
> Signed-off-by: James Clark <[email protected]>
> ---
> drivers/hwtracing/coresight/coresight-core.c | 86 +++++++-------------
> drivers/hwtracing/coresight/coresight-tpda.c | 12 ++-
> include/linux/coresight.h | 2 -
> 3 files changed, 38 insertions(+), 62 deletions(-)
>
> diff --git a/drivers/hwtracing/coresight/coresight-core.c b/drivers/hwtracing/coresight/coresight-core.c
> index ab226441e5f4..1d0bd1586590 100644
> --- a/drivers/hwtracing/coresight/coresight-core.c
> +++ b/drivers/hwtracing/coresight/coresight-core.c
> @@ -279,29 +279,18 @@ EXPORT_SYMBOL_GPL(coresight_add_helper);
> static int coresight_enable_sink(struct coresight_device *csdev,
> enum cs_mode mode, void *data)
> {
> - int ret = sink_ops(csdev)->enable(csdev, mode, data);
> -
> - if (ret)
> - return ret;
> -
> - csdev->enable = true;
> -
> - return 0;
> + return sink_ops(csdev)->enable(csdev, mode, data);
> }
>
> static void coresight_disable_sink(struct coresight_device *csdev)
> {
> - int ret = sink_ops(csdev)->disable(csdev);
> - if (ret)
> - return;
> - csdev->enable = false;
> + sink_ops(csdev)->disable(csdev);
> }
>
> static int coresight_enable_link(struct coresight_device *csdev,
> struct coresight_device *parent,
> struct coresight_device *child)
> {
> - int ret = 0;
> int link_subtype;
> struct coresight_connection *inconn, *outconn;
>
> @@ -317,19 +306,13 @@ static int coresight_enable_link(struct coresight_device *csdev,
> if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT && IS_ERR(outconn))
> return PTR_ERR(outconn);
>
> - ret = link_ops(csdev)->enable(csdev, inconn, outconn);
> - if (!ret)
> - csdev->enable = true;
> -
> - return ret;
> + return link_ops(csdev)->enable(csdev, inconn, outconn);
> }
>
> static void coresight_disable_link(struct coresight_device *csdev,
> struct coresight_device *parent,
> struct coresight_device *child)
> {
> - int i;
> - int link_subtype;
> struct coresight_connection *inconn, *outconn;
>
> if (!parent || !child)
> @@ -337,26 +320,8 @@ static void coresight_disable_link(struct coresight_device *csdev,
>
> inconn = coresight_find_out_connection(parent, csdev);
> outconn = coresight_find_out_connection(csdev, child);
> - link_subtype = csdev->subtype.link_subtype;
>
> link_ops(csdev)->disable(csdev, inconn, outconn);
> -
> - if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
> - for (i = 0; i < csdev->pdata->nr_inconns; i++)
> - if (atomic_read(&csdev->pdata->in_conns[i]->dest_refcnt) !=
> - 0)
> - return;
> - } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
> - for (i = 0; i < csdev->pdata->nr_outconns; i++)
> - if (atomic_read(&csdev->pdata->out_conns[i]->src_refcnt) !=
> - 0)
> - return;
> - } else {
> - if (atomic_read(&csdev->refcnt) != 0)
> - return;
> - }
> -
> - csdev->enable = false;
> }
>
> int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
> @@ -364,11 +329,16 @@ int coresight_enable_source(struct coresight_device *csdev, enum cs_mode mode,
> {
> int ret;
>
> - if (!csdev->enable) {
> + /*
> + * Comparison with CS_MODE_SYSFS works without taking any device
> + * specific spinlock because the truthyness of that comparison can only
> + * change with coresight_mutex held, which we already have here.
> + */
> + lockdep_assert_held(&coresight_mutex);
> + if (local_read(&csdev->mode) != CS_MODE_SYSFS) {
> ret = source_ops(csdev)->enable(csdev, data, mode);
> if (ret)
> return ret;
> - csdev->enable = true;
> }
>
> atomic_inc(&csdev->refcnt);
> @@ -385,22 +355,12 @@ static bool coresight_is_helper(struct coresight_device *csdev)
> static int coresight_enable_helper(struct coresight_device *csdev,
> enum cs_mode mode, void *data)
> {
> - int ret = helper_ops(csdev)->enable(csdev, mode, data);
> -
> - if (ret)
> - return ret;
> -
> - csdev->enable = true;
> - return 0;
> + return helper_ops(csdev)->enable(csdev, mode, data);
> }
>
> static void coresight_disable_helper(struct coresight_device *csdev)
> {
> - int ret = helper_ops(csdev)->disable(csdev, NULL);
> -
> - if (ret)
> - return;
> - csdev->enable = false;
> + helper_ops(csdev)->disable(csdev, NULL);
> }
>
> static void coresight_disable_helpers(struct coresight_device *csdev)
> @@ -445,11 +405,15 @@ EXPORT_SYMBOL_GPL(coresight_disable_source);
> static bool coresight_disable_source_sysfs(struct coresight_device *csdev,
> void *data)
> {
> + lockdep_assert_held(&coresight_mutex);
> + if (local_read(&csdev->mode) != CS_MODE_SYSFS)
> + return false;
> +
> if (atomic_dec_return(&csdev->refcnt) == 0) {
> coresight_disable_source(csdev, data);
> - csdev->enable = false;
> + return true;
> }
> - return !csdev->enable;
> + return false;
> }
>
> /*
> @@ -1097,7 +1061,13 @@ int coresight_enable(struct coresight_device *csdev)
> if (ret)
> goto out;
>
> - if (csdev->enable) {
> + /*
> + * mode == SYSFS implies that it's already enabled. Don't look at the
> + * refcount to determine this because we don't claim the source until
> + * coresight_enable_source() so can still race with Perf mode which
> + * doesn't hold coresight_mutex.
> + */
> + if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
> /*
> * There could be multiple applications driving the software
> * source. So keep the refcount for each such user when the
> @@ -1183,7 +1153,7 @@ void coresight_disable(struct coresight_device *csdev)
> if (ret)
> goto out;
>
> - if (!csdev->enable || !coresight_disable_source_sysfs(csdev, NULL))
> + if (!coresight_disable_source_sysfs(csdev, NULL))
> goto out;
>
> switch (csdev->subtype.source_subtype) {
> @@ -1249,7 +1219,9 @@ static ssize_t enable_source_show(struct device *dev,
> {
> struct coresight_device *csdev = to_coresight_device(dev);
>
> - return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
> + guard(mutex)(&coresight_mutex);
> + return scnprintf(buf, PAGE_SIZE, "%u\n",
> + local_read(&csdev->mode) == CS_MODE_SYSFS);
> }
>
> static ssize_t enable_source_store(struct device *dev,
> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c b/drivers/hwtracing/coresight/coresight-tpda.c
> index 5f82737c37bb..65c70995ab00 100644
> --- a/drivers/hwtracing/coresight/coresight-tpda.c
> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
> @@ -148,7 +148,11 @@ static int __tpda_enable(struct tpda_drvdata *drvdata, int port)
>
> CS_UNLOCK(drvdata->base);
>
> - if (!drvdata->csdev->enable)
> + /*
> + * Only do pre-port enable for first port that calls enable when the
> + * device's main refcount is still 0
> + */
> + if (!atomic_read(&drvdata->csdev->refcnt))
> tpda_enable_pre_port(drvdata);
Relying on the "csdev->enable" to do pre-port configuration looks like
a complete hack to me. This could have been performed once and for all
during the probe time, at say, tpda_init_default_data(). That value is
(drvdata->atid) never updated and need not be re-written unless the
value is lost during a power idle.
Mao, Tao, are you able to confirm this ? If that is the case, we don't
need this csdev->refcnt.
>
> ret = tpda_enable_port(drvdata, port);
> @@ -169,6 +173,7 @@ static int tpda_enable(struct coresight_device *csdev,
> ret = __tpda_enable(drvdata, in->dest_port);
> if (!ret) {
> atomic_inc(&in->dest_refcnt);
> + atomic_inc(&csdev->refcnt);
> dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n", in->dest_port);
> }
> }
> @@ -197,9 +202,10 @@ static void tpda_disable(struct coresight_device *csdev,
> struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>
> spin_lock(&drvdata->spinlock);
> - if (atomic_dec_return(&in->dest_refcnt) == 0)
> + if (atomic_dec_return(&in->dest_refcnt) == 0) {
> __tpda_disable(drvdata, in->dest_port);
> -
> + atomic_dec(&csdev->refcnt);
If we need this, then: This should be performed outside the if () isn't it ?
e.g.,
Operation: in_conn->refcnt csdev->refcnt
port_enable : port0 0 - > 1 0 - > 1
port_enable : port0 1 - > 2 1 - > 2
port_disable: port0 2 - > 1 2 (no change)
port_disable: port0 1 - > 0 2 - > 1
As you can see the csdev->refcnt skipped a dec.
Suzuki
> + }
> spin_unlock(&drvdata->spinlock);
>
> dev_dbg(drvdata->dev, "TPDA inport %d disabled\n", in->dest_port);
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index ba817f563ff7..46e6667f72ce 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -233,7 +233,6 @@ struct coresight_sysfs_link {
> * a non-atomic read would also work.
> * @refcnt: keep track of what is in use.
> * @orphan: true if the component has connections that haven't been linked.
> - * @enable: 'true' if component is currently part of an active path.
> * @sysfs_sink_activated: 'true' when a sink has been selected for use via sysfs
> * by writing a 1 to the 'enable_sink' file. A sink can be
> * activated but not yet enabled. Enabling for a _sink_ happens
> @@ -260,7 +259,6 @@ struct coresight_device {
> local_t mode;
> atomic_t refcnt;
> bool orphan;
> - bool enable;
> /* sink specific fields */
> bool sysfs_sink_activated;
> struct dev_ext_attribute *ea;
On 12/12/2023 15:54, James Clark wrote:
> At the moment the core file contains both sysfs functionality and
> core functionality, while the Perf mode is in a separate file in
> coresight-etm-perf.c
>
> Many of the functions have ambiguous names like
> coresight_enable_source() which actually only work in relation to the
> sysfs mode. To avoid further confusion, move everything that isn't core
> functionality into the sysfs file and append _sysfs to the ambiguous
> functions.
>
> Signed-off-by: James Clark <[email protected]>
The changes look good to me. One minor comment below.
..
> +struct device_type coresight_dev_type[] = {
> + {
> + .name = "sink",
> + .groups = coresight_sink_groups,
> + },
> + {
> + .name = "link",
> + },
> + {
> + .name = "linksink",
> + .groups = coresight_sink_groups,
> + },
> + {
> + .name = "source",
> + .groups = coresight_source_groups,
> + },
> + {
> + .name = "helper",
> + }
> +};
> +/* Ensure the enum matches the names and groups */
> +static_assert(ARRAY_SIZE(coresight_dev_type) == CORESIGHT_DEV_TYPE_MAX);
As a general cleanup, while you are at it, could we please replace this
with explicit member initialisers as a follow up patch ?
i.e.,
struct device_typ coresight_dev_type[CORESIGHT_DEV_TYPE_MAX] = {
[CORESIGHT_DEV_TYPE_SINK] = {
.name = "sink",
.groups = coresight_sink_groups,
},
[CORESIGHT_DEV_TYPE_LINK] =
..
}
Thanks
Suzuki
Hi James
On 12/12/2023 15:54, James Clark wrote:
> These are a bit annoying to keep up to date when the function signatures
> change. But if CONFIG_CORESIGHT isn't enabled, then they're not used
> anyway so just delete them.
>
Have you tried building an arm32 kernel with this change in ? Looks like
arch/arm/kernel/hw_breakpoint.c includes linux/coresight.h and a build
with CONFIG_CORSIGHT=n might break the build ? So is
drivers/accel/habanalabs/common/habanalabs.h. Now, I am not sure if they
really need it (even if they do, we may be able to remove the dependency
on the header file.
Suzuki
> Signed-off-by: James Clark <[email protected]>
> ---
> include/linux/coresight.h | 79 ---------------------------------------
> 1 file changed, 79 deletions(-)
>
> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> index 4400d554a16b..c5be46d7f85c 100644
> --- a/include/linux/coresight.h
> +++ b/include/linux/coresight.h
> @@ -391,8 +391,6 @@ struct coresight_ops {
> const struct coresight_ops_helper *helper_ops;
> };
>
> -#if IS_ENABLED(CONFIG_CORESIGHT)
> -
> static inline u32 csdev_access_relaxed_read32(struct csdev_access *csa,
> u32 offset)
> {
> @@ -611,83 +609,6 @@ void coresight_relaxed_write64(struct coresight_device *csdev,
> u64 val, u32 offset);
> void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset);
>
> -#else
> -static inline struct coresight_device *
> -coresight_register(struct coresight_desc *desc) { return NULL; }
> -static inline void coresight_unregister(struct coresight_device *csdev) {}
> -static inline int
> -coresight_enable_sysfs(struct coresight_device *csdev) { return -ENOSYS; }
> -static inline void coresight_disable_sysfs(struct coresight_device *csdev) {}
> -
> -static inline int coresight_timeout(struct csdev_access *csa, u32 offset,
> - int position, int value)
> -{
> - return 1;
> -}
> -
> -static inline int coresight_claim_device_unlocked(struct coresight_device *csdev)
> -{
> - return -EINVAL;
> -}
> -
> -static inline int coresight_claim_device(struct coresight_device *csdev)
> -{
> - return -EINVAL;
> -}
> -
> -static inline void coresight_disclaim_device(struct coresight_device *csdev) {}
> -static inline void coresight_disclaim_device_unlocked(struct coresight_device *csdev) {}
> -
> -static inline bool coresight_loses_context_with_cpu(struct device *dev)
> -{
> - return false;
> -}
> -
> -static inline u32 coresight_relaxed_read32(struct coresight_device *csdev, u32 offset)
> -{
> - WARN_ON_ONCE(1);
> - return 0;
> -}
> -
> -static inline u32 coresight_read32(struct coresight_device *csdev, u32 offset)
> -{
> - WARN_ON_ONCE(1);
> - return 0;
> -}
> -
> -static inline void coresight_write32(struct coresight_device *csdev, u32 val, u32 offset)
> -{
> -}
> -
> -static inline void coresight_relaxed_write32(struct coresight_device *csdev,
> - u32 val, u32 offset)
> -{
> -}
> -
> -static inline u64 coresight_relaxed_read64(struct coresight_device *csdev,
> - u32 offset)
> -{
> - WARN_ON_ONCE(1);
> - return 0;
> -}
> -
> -static inline u64 coresight_read64(struct coresight_device *csdev, u32 offset)
> -{
> - WARN_ON_ONCE(1);
> - return 0;
> -}
> -
> -static inline void coresight_relaxed_write64(struct coresight_device *csdev,
> - u64 val, u32 offset)
> -{
> -}
> -
> -static inline void coresight_write64(struct coresight_device *csdev, u64 val, u32 offset)
> -{
> -}
> -
> -#endif /* IS_ENABLED(CONFIG_CORESIGHT) */
> -
> extern int coresight_get_cpu(struct device *dev);
>
> struct coresight_platform_data *coresight_get_platform_data(struct device *dev);
On 09/01/2024 10:38, Suzuki K Poulose wrote:
> Hi James
>
> On 12/12/2023 15:54, James Clark wrote:
>> These are a bit annoying to keep up to date when the function signatures
>> change. But if CONFIG_CORESIGHT isn't enabled, then they're not used
>> anyway so just delete them.
>>
>
> Have you tried building an arm32 kernel with this change in ? Looks like
> arch/arm/kernel/hw_breakpoint.c includes linux/coresight.h and a build
> with CONFIG_CORSIGHT=n might break the build ? So is
arm32 and CONFIG_CORESIGHT=n works because hw_breakpoint.c doesn't use
any of those symbols, only #defines that were outside the #if
IS_ENABLED(CONFIG_CORESIGHT), specifically CORESIGHT_UNLOCK.
> drivers/accel/habanalabs/common/habanalabs.h. Now, I am not sure if they
habanalabs is interesting, it depends on X86_64, but CONFIG_CORESIGHT
depends on ARM || ARM64, so I think we can assume it's also only looking
for #defines and inlines, and not actual code.
Either way I can't find any build config that actually ever built this,
meaning it's always been dead code. I would have expected some build
robot to have flagged an error by now as I've seen that on other
coresight patches.
> really need it (even if they do, we may be able to remove the dependency
> on the header file.
>
They do really need it, also for the CORESIGHT_UNLOCK definition, but
not any functions.
> Suzuki
>
>> Signed-off-by: James Clark <[email protected]>
>> ---
>> include/linux/coresight.h | 79 ---------------------------------------
>> 1 file changed, 79 deletions(-)
>>
>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
>> index 4400d554a16b..c5be46d7f85c 100644
>> --- a/include/linux/coresight.h
>> +++ b/include/linux/coresight.h
>> @@ -391,8 +391,6 @@ struct coresight_ops {
>> const struct coresight_ops_helper *helper_ops;
>> };
>> -#if IS_ENABLED(CONFIG_CORESIGHT)
>> -
>> static inline u32 csdev_access_relaxed_read32(struct csdev_access *csa,
>> u32 offset)
>> {
>> @@ -611,83 +609,6 @@ void coresight_relaxed_write64(struct
>> coresight_device *csdev,
>> u64 val, u32 offset);
>> void coresight_write64(struct coresight_device *csdev, u64 val, u32
>> offset);
>> -#else
>> -static inline struct coresight_device *
>> -coresight_register(struct coresight_desc *desc) { return NULL; }
>> -static inline void coresight_unregister(struct coresight_device
>> *csdev) {}
>> -static inline int
>> -coresight_enable_sysfs(struct coresight_device *csdev) { return
>> -ENOSYS; }
>> -static inline void coresight_disable_sysfs(struct coresight_device
>> *csdev) {}
>> -
>> -static inline int coresight_timeout(struct csdev_access *csa, u32
>> offset,
>> - int position, int value)
>> -{
>> - return 1;
>> -}
>> -
>> -static inline int coresight_claim_device_unlocked(struct
>> coresight_device *csdev)
>> -{
>> - return -EINVAL;
>> -}
>> -
>> -static inline int coresight_claim_device(struct coresight_device *csdev)
>> -{
>> - return -EINVAL;
>> -}
>> -
>> -static inline void coresight_disclaim_device(struct coresight_device
>> *csdev) {}
>> -static inline void coresight_disclaim_device_unlocked(struct
>> coresight_device *csdev) {}
>> -
>> -static inline bool coresight_loses_context_with_cpu(struct device *dev)
>> -{
>> - return false;
>> -}
>> -
>> -static inline u32 coresight_relaxed_read32(struct coresight_device
>> *csdev, u32 offset)
>> -{
>> - WARN_ON_ONCE(1);
>> - return 0;
>> -}
>> -
>> -static inline u32 coresight_read32(struct coresight_device *csdev,
>> u32 offset)
>> -{
>> - WARN_ON_ONCE(1);
>> - return 0;
>> -}
>> -
>> -static inline void coresight_write32(struct coresight_device *csdev,
>> u32 val, u32 offset)
>> -{
>> -}
>> -
>> -static inline void coresight_relaxed_write32(struct coresight_device
>> *csdev,
>> - u32 val, u32 offset)
>> -{
>> -}
>> -
>> -static inline u64 coresight_relaxed_read64(struct coresight_device
>> *csdev,
>> - u32 offset)
>> -{
>> - WARN_ON_ONCE(1);
>> - return 0;
>> -}
>> -
>> -static inline u64 coresight_read64(struct coresight_device *csdev,
>> u32 offset)
>> -{
>> - WARN_ON_ONCE(1);
>> - return 0;
>> -}
>> -
>> -static inline void coresight_relaxed_write64(struct coresight_device
>> *csdev,
>> - u64 val, u32 offset)
>> -{
>> -}
>> -
>> -static inline void coresight_write64(struct coresight_device *csdev,
>> u64 val, u32 offset)
>> -{
>> -}
>> -
>> -#endif /* IS_ENABLED(CONFIG_CORESIGHT) */
>> -
>> extern int coresight_get_cpu(struct device *dev);
>> struct coresight_platform_data *coresight_get_platform_data(struct
>> device *dev);
>
On 09/01/2024 16:48, James Clark wrote:
>
>
> On 09/01/2024 10:38, Suzuki K Poulose wrote:
>> Hi James
>>
>> On 12/12/2023 15:54, James Clark wrote:
>>> These are a bit annoying to keep up to date when the function signatures
>>> change. But if CONFIG_CORESIGHT isn't enabled, then they're not used
>>> anyway so just delete them.
>>>
>>
>> Have you tried building an arm32 kernel with this change in ? Looks like
>> arch/arm/kernel/hw_breakpoint.c includes linux/coresight.h and a build
>> with CONFIG_CORSIGHT=n might break the build ? So is
>
> arm32 and CONFIG_CORESIGHT=n works because hw_breakpoint.c doesn't use
> any of those symbols, only #defines that were outside the #if
> IS_ENABLED(CONFIG_CORESIGHT), specifically CORESIGHT_UNLOCK.
>
>> drivers/accel/habanalabs/common/habanalabs.h. Now, I am not sure if they
>
> habanalabs is interesting, it depends on X86_64, but CONFIG_CORESIGHT
> depends on ARM || ARM64, so I think we can assume it's also only looking
> for #defines and inlines, and not actual code.
>
> Either way I can't find any build config that actually ever built this,
> meaning it's always been dead code. I would have expected some build
> robot to have flagged an error by now as I've seen that on other
> coresight patches.
>
>> really need it (even if they do, we may be able to remove the dependency
>> on the header file.
>>
>
> They do really need it, also for the CORESIGHT_UNLOCK definition, but
> not any functions.
Thanks for checking this.
Suzuki
On 08/01/2024 14:42, Suzuki K Poulose wrote:
> Hi James
>
> +Cc: Tao Zhang <[email protected]>
> +Cc: Mao Jinlong <[email protected]>
>
> On 12/12/2023 15:54, James Clark wrote:
>> 'enable', which probably should have been 'enabled', is only ever read
>> in the core code in relation to controlling sources, and specifically
>> only sources in sysfs mode. Confusingly it's not labelled as such and
>> relying on it can be a source of bugs like the one fixed by
>> commit 078dbba3f0c9 ("coresight: Fix crash when Perf and sysfs modes are
>> used concurrently").
>>
>> Most importantly, it can only be used when the coresight_mutex is held
>> which is only done when enabling and disabling paths in sysfs mode, and
>> not Perf mode.
>
>
> I think we may be able to relax this a bit for the syfs. The sole reason
> for holding the mutex is for the "build_path" (and get_enabled_sink)
> where we need to make sure that no devices are removed/added. We hold
> necessary refcount on the device and the module (via
> coresight_grab_device()). After which, we should be able to release the
> mutex and perform the rest without it in coresight_enable()
>
After looking at the per-sink trace ID maps a bit more, I'm not sure if
it will be worth the mental effort and risk to relax the sysfs locking
right now.
We also currently have other things like writing to the global
tracer_path which are outside of build_path/get_enabled_sink. But for
the per-sink maps change we'll also have some tracking for sysfs mode
about which sink map was used for each source and sink. And this state
will be accessed across multiple sources, and after building the path,
so it makes sense to leave the locking as-is for now IMO.
I also can't see a realistic gain from doing it, most sysfs use cases
would be done from a single threaded script. Maybe in the future we
could do the change to move the per-device locks into struct
coresight_device, and then the core code can use them for things that
need to be locked, but don't need the full coresight_mutex. And then
that would also work for the per-sink case. But at the moment each
device has its own lock so that's difficult.
>> So to prevent its usage spreading and leaking out to
>> other devices, remove it.
>>
>> It's use is equivalent to checking if the mode is currently sysfs, as
>> due to the coresight_mutex lock, mode == CS_MODE_SYSFS can only become
>> true or untrue when that lock is held, and when mode == CS_MODE_SYSFS
>> the device is both enabled and in sysfs mode.
>
> All of the above makes sense and looks good to me.
>
>>
>> The one place it was used outside of the core code is in TPDA, but that
>> pattern is more appropriately represented using refcounts inside the
>> device's own spinlock.
>
> But, I think we can clean up this code a bit more better. See below.
>
>>
>> Signed-off-by: James Clark <[email protected]>
>> ---
>> drivers/hwtracing/coresight/coresight-core.c | 86 +++++++-------------
>> drivers/hwtracing/coresight/coresight-tpda.c | 12 ++-
>> include/linux/coresight.h | 2 -
>> 3 files changed, 38 insertions(+), 62 deletions(-)
>>
>> diff --git a/drivers/hwtracing/coresight/coresight-core.c
>> b/drivers/hwtracing/coresight/coresight-core.c
>> index ab226441e5f4..1d0bd1586590 100644
>> --- a/drivers/hwtracing/coresight/coresight-core.c
>> +++ b/drivers/hwtracing/coresight/coresight-core.c
>> @@ -279,29 +279,18 @@ EXPORT_SYMBOL_GPL(coresight_add_helper);
>> static int coresight_enable_sink(struct coresight_device *csdev,
>> enum cs_mode mode, void *data)
>> {
>> - int ret = sink_ops(csdev)->enable(csdev, mode, data);
>> -
>> - if (ret)
>> - return ret;
>> -
>> - csdev->enable = true;
>> -
>> - return 0;
>> + return sink_ops(csdev)->enable(csdev, mode, data);
>> }
>> static void coresight_disable_sink(struct coresight_device *csdev)
>> {
>> - int ret = sink_ops(csdev)->disable(csdev);
>> - if (ret)
>> - return;
>> - csdev->enable = false;
>> + sink_ops(csdev)->disable(csdev);
>> }
>> static int coresight_enable_link(struct coresight_device *csdev,
>> struct coresight_device *parent,
>> struct coresight_device *child)
>> {
>> - int ret = 0;
>> int link_subtype;
>> struct coresight_connection *inconn, *outconn;
>> @@ -317,19 +306,13 @@ static int coresight_enable_link(struct
>> coresight_device *csdev,
>> if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT &&
>> IS_ERR(outconn))
>> return PTR_ERR(outconn);
>> - ret = link_ops(csdev)->enable(csdev, inconn, outconn);
>> - if (!ret)
>> - csdev->enable = true;
>> -
>> - return ret;
>> + return link_ops(csdev)->enable(csdev, inconn, outconn);
>> }
>> static void coresight_disable_link(struct coresight_device *csdev,
>> struct coresight_device *parent,
>> struct coresight_device *child)
>> {
>> - int i;
>> - int link_subtype;
>> struct coresight_connection *inconn, *outconn;
>> if (!parent || !child)
>> @@ -337,26 +320,8 @@ static void coresight_disable_link(struct
>> coresight_device *csdev,
>> inconn = coresight_find_out_connection(parent, csdev);
>> outconn = coresight_find_out_connection(csdev, child);
>> - link_subtype = csdev->subtype.link_subtype;
>> link_ops(csdev)->disable(csdev, inconn, outconn);
>> -
>> - if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
>> - for (i = 0; i < csdev->pdata->nr_inconns; i++)
>> - if (atomic_read(&csdev->pdata->in_conns[i]->dest_refcnt) !=
>> - 0)
>> - return;
>> - } else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
>> - for (i = 0; i < csdev->pdata->nr_outconns; i++)
>> - if (atomic_read(&csdev->pdata->out_conns[i]->src_refcnt) !=
>> - 0)
>> - return;
>> - } else {
>> - if (atomic_read(&csdev->refcnt) != 0)
>> - return;
>> - }
>> -
>> - csdev->enable = false;
>> }
>> int coresight_enable_source(struct coresight_device *csdev, enum
>> cs_mode mode,
>> @@ -364,11 +329,16 @@ int coresight_enable_source(struct
>> coresight_device *csdev, enum cs_mode mode,
>> {
>> int ret;
>> - if (!csdev->enable) {
>> + /*
>> + * Comparison with CS_MODE_SYSFS works without taking any device
>> + * specific spinlock because the truthyness of that comparison
>> can only
>> + * change with coresight_mutex held, which we already have here.
>> + */
>> + lockdep_assert_held(&coresight_mutex);
>> + if (local_read(&csdev->mode) != CS_MODE_SYSFS) {
>> ret = source_ops(csdev)->enable(csdev, data, mode);
>> if (ret)
>> return ret;
>> - csdev->enable = true;
>> }
>> atomic_inc(&csdev->refcnt);
>> @@ -385,22 +355,12 @@ static bool coresight_is_helper(struct
>> coresight_device *csdev)
>> static int coresight_enable_helper(struct coresight_device *csdev,
>> enum cs_mode mode, void *data)
>> {
>> - int ret = helper_ops(csdev)->enable(csdev, mode, data);
>> -
>> - if (ret)
>> - return ret;
>> -
>> - csdev->enable = true;
>> - return 0;
>> + return helper_ops(csdev)->enable(csdev, mode, data);
>> }
>> static void coresight_disable_helper(struct coresight_device *csdev)
>> {
>> - int ret = helper_ops(csdev)->disable(csdev, NULL);
>> -
>> - if (ret)
>> - return;
>> - csdev->enable = false;
>> + helper_ops(csdev)->disable(csdev, NULL);
>> }
>> static void coresight_disable_helpers(struct coresight_device *csdev)
>> @@ -445,11 +405,15 @@ EXPORT_SYMBOL_GPL(coresight_disable_source);
>> static bool coresight_disable_source_sysfs(struct coresight_device
>> *csdev,
>> void *data)
>> {
>> + lockdep_assert_held(&coresight_mutex);
>> + if (local_read(&csdev->mode) != CS_MODE_SYSFS)
>> + return false;
>> +
>> if (atomic_dec_return(&csdev->refcnt) == 0) {
>> coresight_disable_source(csdev, data);
>> - csdev->enable = false;
>> + return true;
>> }
>> - return !csdev->enable;
>> + return false;
>> }
>> /*
>> @@ -1097,7 +1061,13 @@ int coresight_enable(struct coresight_device
>> *csdev)
>> if (ret)
>> goto out;
>> - if (csdev->enable) {
>> + /*
>> + * mode == SYSFS implies that it's already enabled. Don't look at
>> the
>> + * refcount to determine this because we don't claim the source
>> until
>> + * coresight_enable_source() so can still race with Perf mode which
>> + * doesn't hold coresight_mutex.
>> + */
>> + if (local_read(&csdev->mode) == CS_MODE_SYSFS) {
>> /*
>> * There could be multiple applications driving the software
>> * source. So keep the refcount for each such user when the
>> @@ -1183,7 +1153,7 @@ void coresight_disable(struct coresight_device
>> *csdev)
>> if (ret)
>> goto out;
>> - if (!csdev->enable || !coresight_disable_source_sysfs(csdev,
>> NULL))
>> + if (!coresight_disable_source_sysfs(csdev, NULL))
>> goto out;
>> switch (csdev->subtype.source_subtype) {
>> @@ -1249,7 +1219,9 @@ static ssize_t enable_source_show(struct device
>> *dev,
>> {
>> struct coresight_device *csdev = to_coresight_device(dev);
>> - return scnprintf(buf, PAGE_SIZE, "%u\n", csdev->enable);
>> + guard(mutex)(&coresight_mutex);
>> + return scnprintf(buf, PAGE_SIZE, "%u\n",
>> + local_read(&csdev->mode) == CS_MODE_SYSFS);
>> }
>> static ssize_t enable_source_store(struct device *dev,
>> diff --git a/drivers/hwtracing/coresight/coresight-tpda.c
>> b/drivers/hwtracing/coresight/coresight-tpda.c
>> index 5f82737c37bb..65c70995ab00 100644
>> --- a/drivers/hwtracing/coresight/coresight-tpda.c
>> +++ b/drivers/hwtracing/coresight/coresight-tpda.c
>> @@ -148,7 +148,11 @@ static int __tpda_enable(struct tpda_drvdata
>> *drvdata, int port)
>> CS_UNLOCK(drvdata->base);
>> - if (!drvdata->csdev->enable)
>> + /*
>> + * Only do pre-port enable for first port that calls enable when the
>> + * device's main refcount is still 0
>> + */
>> + if (!atomic_read(&drvdata->csdev->refcnt))
>> tpda_enable_pre_port(drvdata);
>
> Relying on the "csdev->enable" to do pre-port configuration looks like
> a complete hack to me. This could have been performed once and for all
> during the probe time, at say, tpda_init_default_data(). That value is
> (drvdata->atid) never updated and need not be re-written unless the
> value is lost during a power idle.
>
> Mao, Tao, are you able to confirm this ? If that is the case, we don't
> need this csdev->refcnt.
>
"unless the value is lost during a power idle."
That one might be a reason to do it. I suppose it makes sense to write
all the registers on enable, but not to keep re-writing the trace ID
again for every port that's used.
>> ret = tpda_enable_port(drvdata, port);
>> @@ -169,6 +173,7 @@ static int tpda_enable(struct coresight_device
>> *csdev,
>> ret = __tpda_enable(drvdata, in->dest_port);
>> if (!ret) {
>> atomic_inc(&in->dest_refcnt);
>> + atomic_inc(&csdev->refcnt);
>> dev_dbg(drvdata->dev, "TPDA inport %d enabled.\n",
>> in->dest_port);
>> }
>> }
>> @@ -197,9 +202,10 @@ static void tpda_disable(struct coresight_device
>> *csdev,
>> struct tpda_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
>> spin_lock(&drvdata->spinlock);
>> - if (atomic_dec_return(&in->dest_refcnt) == 0)
>> + if (atomic_dec_return(&in->dest_refcnt) == 0) {
>> __tpda_disable(drvdata, in->dest_port);
>> -
>> + atomic_dec(&csdev->refcnt);
>
> If we need this, then: This should be performed outside the if () isn't
> it ?
>
> e.g.,
>
> Operation: in_conn->refcnt csdev->refcnt
> port_enable : port0 0 - > 1 0 - > 1
> port_enable : port0 1 - > 2 1 - > 2
I didn't get 1 -> 2 here, because the in->dest_refcnt is only
incremented once if it was already 0 (although it is once for each port):
if (atomic_read(&in->dest_refcnt) == 0) {
ret = __tpda_enable(drvdata, in->dest_port);
if (!ret) {
atomic_inc(&in->dest_refcnt);
That basically makes csdev->refcnt count how many ports were used, but
each port's refcount can only be used once. And then when each port is
disabled csdev->refcnt returns to zero on the last port.
> port_disable: port0 2 - > 1 2 (no change)
> port_disable: port0 1 - > 0 2 - > 1
>
> As you can see the csdev->refcnt skipped a dec.
>
> Suzuki
>
>
>> + }
>> spin_unlock(&drvdata->spinlock);
>> dev_dbg(drvdata->dev, "TPDA inport %d disabled\n",
>> in->dest_port);
>> diff --git a/include/linux/coresight.h b/include/linux/coresight.h
>> index ba817f563ff7..46e6667f72ce 100644
>> --- a/include/linux/coresight.h
>> +++ b/include/linux/coresight.h
>> @@ -233,7 +233,6 @@ struct coresight_sysfs_link {
>> * a non-atomic read would also work.
>> * @refcnt: keep track of what is in use.
>> * @orphan: true if the component has connections that haven't
>> been linked.
>> - * @enable: 'true' if component is currently part of an active path.
>> * @sysfs_sink_activated: 'true' when a sink has been selected for
>> use via sysfs
>> * by writing a 1 to the 'enable_sink' file. A sink can be
>> * activated but not yet enabled. Enabling for a _sink_ happens
>> @@ -260,7 +259,6 @@ struct coresight_device {
>> local_t mode;
>> atomic_t refcnt;
>> bool orphan;
>> - bool enable;
>> /* sink specific fields */
>> bool sysfs_sink_activated;
>> struct dev_ext_attribute *ea;
>
On 19/01/2024 09:59, James Clark wrote:
>
>
> On 08/01/2024 14:42, Suzuki K Poulose wrote:
>> Hi James
>>
>> +Cc: Tao Zhang <[email protected]>
>> +Cc: Mao Jinlong <[email protected]>
>>
>> On 12/12/2023 15:54, James Clark wrote:
>>> 'enable', which probably should have been 'enabled', is only ever read
>>> in the core code in relation to controlling sources, and specifically
>>> only sources in sysfs mode. Confusingly it's not labelled as such and
>>> relying on it can be a source of bugs like the one fixed by
>>> commit 078dbba3f0c9 ("coresight: Fix crash when Perf and sysfs modes are
>>> used concurrently").
>>>
>>> Most importantly, it can only be used when the coresight_mutex is held
>>> which is only done when enabling and disabling paths in sysfs mode, and
>>> not Perf mode.
>>
>>
>> I think we may be able to relax this a bit for the syfs. The sole reason
>> for holding the mutex is for the "build_path" (and get_enabled_sink)
>> where we need to make sure that no devices are removed/added. We hold
>> necessary refcount on the device and the module (via
>> coresight_grab_device()). After which, we should be able to release the
>> mutex and perform the rest without it in coresight_enable()
>>
>
> After looking at the per-sink trace ID maps a bit more, I'm not sure if
> it will be worth the mental effort and risk to relax the sysfs locking
> right now.
>
> We also currently have other things like writing to the global
> tracer_path which are outside of build_path/get_enabled_sink. But for
> the per-sink maps change we'll also have some tracking for sysfs mode
> about which sink map was used for each source and sink. And this state
> will be accessed across multiple sources, and after building the path,
> so it makes sense to leave the locking as-is for now IMO.
>
> I also can't see a realistic gain from doing it, most sysfs use cases
> would be done from a single threaded script. Maybe in the future we
> could do the change to move the per-device locks into struct
> coresight_device, and then the core code can use them for things that
> need to be locked, but don't need the full coresight_mutex. And then
> that would also work for the per-sink case. But at the moment each
> device has its own lock so that's difficult.
Ok, we could come back to this after the per-sink trace id pool work.
My observation was about the inconsistency between the perf vs sysfs
mode as you mentioned in the above code.
Suzuki