Re: [PATCH v6 11/16] remoteproc: Properly deal with the resource table when attached
From: Arnaud POULIQUEN
Date: Fri Feb 26 2021 - 11:22:11 EST
On 2/24/21 12:35 AM, Mathieu Poirier wrote:
>
If it is possible to detach the remote processor, keep an untouched
>
copy of the resource table. That way we can start from the same
>
resource table without having to worry about original values or what
>
elements the startup code has changed when re-attaching to the remote
>
processor.
>
>
Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
>
---
>
New for V6:
>
- Double free of the cached table has been fixed.
>
- rproc_reset_loaded_rsc_table() has seen a complete re-write.
>
- rproc_stop() now calls rproc_reset_loaded_rsc_table() rather than
>
dealing with the cached. This allows to properly shutdown a
>
remote processor that was attached to.
>
---
>
>
drivers/remoteproc/remoteproc_core.c | 86 +++++++++++++++++++++++++++-
>
include/linux/remoteproc.h | 3 +
>
2 files changed, 88 insertions(+), 1 deletion(-)
>
>
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
>
index fc01b29290a6..3a4692cc5220 100644
>
--- a/drivers/remoteproc/remoteproc_core.c
>
+++ b/drivers/remoteproc/remoteproc_core.c
>
@@ -1556,6 +1556,21 @@ static int rproc_set_loaded_rsc_table(struct rproc *rproc)
>
return ret;
>
}
>
>
+ /*
>
+ * If it is possible to detach the remote processor, keep an untouched
>
+ * copy of the resource table. That way we can start fresh again when
>
+ * the remote processor is re-attached, that is:
>
+ *
>
+ * DETACHED -> ATTACHED -> DETACHED -> ATTACHED
>
+ *
>
+ * Free'd in rproc_reset_loaded_rsc_table().
>
+ */
>
+ if (rproc->ops->detach) {
>
+ rproc->clean_table = kmemdup(table_ptr, table_sz, GFP_KERNEL);
>
+ if (!rproc->clean_table)
>
+ return -ENOMEM;
>
+ }
>
+
>
rproc->cached_table = NULL;
>
rproc->table_ptr = table_ptr;
>
rproc->table_sz = table_sz;
>
@@ -1563,6 +1578,65 @@ static int rproc_set_loaded_rsc_table(struct rproc *rproc)
>
return 0;
>
}
>
>
+static int rproc_reset_loaded_rsc_table(struct rproc *rproc)
I spent some time to review this function that handles both the resource table
for both the stop and detach. To make it easier to read, I would divide it into
two functions.
I added a proposal at the end of this mail.
Regards,
Arnaud
>
+{
>
+ struct resource_table *table_ptr;
>
+
>
+ /*
>
+ * The cached table is already set if the remote processor was started
>
+ * by the remoteproc core.
>
+ */
>
+ if (rproc->state == RPROC_RUNNING) {
>
+ rproc->table_ptr = rproc->cached_table;
>
+ return 0;
>
+ }
>
+
>
+ /* A resource table was never retrieved, nothing to do here */
>
+ if (!rproc->table_ptr)
>
+ return 0;
>
+
>
+ /*
>
+ * If we made it to this point a cached_table _must_ have been
>
+ * allocated in rproc_set_loaded_rsc_table(). If one isn't present
>
+ * something went really wrong and we must complain.
>
+ */
>
+ if (WARN_ON(!rproc->clean_table))
>
+ return -EINVAL;
>
+
>
+ /* Remember where the external entity installed the resource table */
>
+ table_ptr = rproc->table_ptr;
>
+
>
+ /*
>
+ * Make a copy of the resource table currently used by the remote
>
+ * processor. Free'd in rproc_detach() or rproc_shutdown().
>
+ */
>
+ rproc->cached_table = kmemdup(rproc->table_ptr,
>
+ rproc->table_sz, GFP_KERNEL);
>
+ if (!rproc->cached_table)
>
+ return -ENOMEM;
>
+
>
+ /*
>
+ * Use a copy of the resource table for the remainder of the
>
+ * shutdown process.
>
+ */
>
+ rproc->table_ptr = rproc->cached_table;
>
+
>
+ /*
>
+ * Reset the memory area where the firmware loaded the resource table
>
+ * to its original value. That way when we re-attach the remote
>
+ * processor the resource table is clean and ready to be used again.
>
+ */
>
+ memcpy(table_ptr, rproc->clean_table, rproc->table_sz);
>
+
>
+ /*
>
+ * The clean resource table is no longer needed. Allocated in
>
+ * rproc_set_loaded_rsc_table().
>
+ */
>
+ kfree(rproc->clean_table);
>
+
>
+ return 0;
>
+}
>
+
>
/*
>
* Attach to remote processor - similar to rproc_fw_boot() but without
>
* the steps that deal with the firmware image.
>
@@ -1688,7 +1762,11 @@ static int rproc_stop(struct rproc *rproc, bool crashed)
>
rproc_stop_subdevices(rproc, crashed);
>
>
/* the installed resource table is no longer accessible */
>
- rproc->table_ptr = rproc->cached_table;
>
+ ret = rproc_reset_loaded_rsc_table(rproc);
>
+ if (ret) {
>
+ dev_err(dev, "can't reset resource table: %d\n", ret);
>
+ return ret;
>
+ }
>
>
/* power off the remote processor */
>
ret = rproc->ops->stop(rproc);
>
@@ -1721,6 +1799,9 @@ static int __rproc_detach(struct rproc *rproc)
>
/* Stop any subdevices for the remote processor */
>
rproc_stop_subdevices(rproc, false);
>
>
+ /* the installed resource table is no longer accessible */
>
+ ret = rproc_reset_loaded_rsc_table(rproc);
>
+
>
/* Tell the remote processor the core isn't available anymore */
>
ret = rproc->ops->detach(rproc);
>
if (ret) {
>
@@ -1997,6 +2078,9 @@ int rproc_detach(struct rproc *rproc)
>
>
rproc_disable_iommu(rproc);
>
>
+ /* Free the copy of the resource table */
>
+ kfree(rproc->cached_table);
>
+ rproc->cached_table = NULL;
>
rproc->table_ptr = NULL;
>
out:
>
mutex_unlock(&rproc->lock);
>
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>
index e1c843c19cc6..e5f52a12a650 100644
>
--- a/include/linux/remoteproc.h
>
+++ b/include/linux/remoteproc.h
>
@@ -514,6 +514,8 @@ struct rproc_dump_segment {
>
* @recovery_disabled: flag that state if recovery was disabled
>
* @max_notifyid: largest allocated notify id.
>
* @table_ptr: pointer to the resource table in effect
>
+ * @clean_table: copy of the resource table without modifications. Used
>
+ * when a remote processor is attached or detached from the core
>
* @cached_table: copy of the resource table
>
* @table_sz: size of @cached_table
>
* @has_iommu: flag to indicate if remote processor is behind an MMU
>
@@ -550,6 +552,7 @@ struct rproc {
>
bool recovery_disabled;
>
int max_notifyid;
>
struct resource_table *table_ptr;
>
+ struct resource_table *clean_table;
>
struct resource_table *cached_table;
>
size_t table_sz;
>
bool has_iommu;
>
---
drivers/remoteproc/remoteproc_core.c | 101 ++++++++++++++++++++++++++-
include/linux/remoteproc.h | 3 +
2 files changed, 103 insertions(+), 1 deletion(-)
diff --git a/drivers/remoteproc/remoteproc_core.c
b/drivers/remoteproc/remoteproc_core.c
index fc01b29290a6..cc24c360eb8b 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -1556,6 +1556,21 @@ static int rproc_set_loaded_rsc_table(struct rproc *rproc)
return ret;
}
+ /*
+ * If it is possible to detach the remote processor, keep an untouched
+ * copy of the resource table. That way we can start fresh again when
+ * the remote processor is re-attached, that is:
+ *
+ * DETACHED -> ATTACHED -> DETACHED -> ATTACHED
+ *
+ * Free'd in rproc_reset_loaded_rsc_table().
+ */
+ if (rproc->ops->detach) {
+ rproc->clean_table = kmemdup(table_ptr, table_sz, GFP_KERNEL);
+ if (!rproc->clean_table)
+ return -ENOMEM;
+ }
+
rproc->cached_table = NULL;
rproc->table_ptr = table_ptr;
rproc->table_sz = table_sz;
@@ -1563,6 +1578,79 @@ static int rproc_set_loaded_rsc_table(struct rproc *rproc)
return 0;
}
+static int rproc_set_to_cached_rsc_table(struct rproc *rproc)
+{
+ /* A resource table was never retrieved, nothing to do here */
+ if (!rproc->table_ptr)
+ return 0;
+
+ /*
+ * The cached table is already set if the remote processor was started
+ * by the remoteproc core.
+ */
+ if (!rproc->cached_table) {
+ rproc->table_ptr = rproc->cached_table;
+ return 0;
+ }
+
+ /*
+ * Make a copy of the resource table currently used by the remote
+ * processor. Free'd in rproc_detach() or rproc_shutdown().
+ */
+ rproc->cached_table = kmemdup(rproc->table_ptr,
+ rproc->table_sz, GFP_KERNEL);
+ if (!rproc->cached_table)
+ return -ENOMEM;
+
+ /*
+ * Use a copy of the resource table for the remainder of the
+ * shutdown process.
+ */
+ rproc->table_ptr = rproc->cached_table;
+
+ return 0;
+}
+
+static int rproc_reset_loaded_rsc_table(struct rproc *rproc)
+{
+ struct resource_table *table_ptr;
+ int ret;
+
+ /* A resource table was never retrieved, nothing to do here */
+ if (!rproc->table_ptr)
+ return 0;
+
+ /*
+ * If we made it to this point a cached_table _mst_ have been
+ * allocated in rproc_set_loaded_rsc_table(). If one isn't present
+ * something went really wrong and we must complain.
+ */
+ if (WARN_ON(!rproc->clean_table))
+ return -EINVAL;
+
+ /* Remember where the external entity installed the resource table */
+ table_ptr = rproc->table_ptr;
+
+ ret = rproc_set_to_cached_rsc_table(rproc);
+ if (ret)
+ return ret;
+
+ /*
+ * Reset the memory area where the firmware loaded the resource table
+ * to its original value. That way when we re-attach the remote
+ * processor the resource table is clean and ready to be used again.
+ */
+ memcpy(table_ptr, rproc->clean_table, rproc->table_sz);
+
+ /*
+ * The clean resource table is no longer needed. Allocated in
+ * rproc_set_loaded_rsc_table().
+ */
+ kfree(rproc->clean_table);
+
+ return 0;
+}
+
/*
* Attach to remote processor - similar to rproc_fw_boot() but without
* the steps that deal with the firmware image.
@@ -1688,7 +1776,11 @@ static int rproc_stop(struct rproc *rproc, bool crashed)
rproc_stop_subdevices(rproc, crashed);
/* the installed resource table is no longer accessible */
- rproc->table_ptr = rproc->cached_table;
+ ret = rproc_set_to_cached_rsc_table(rproc);
+ if (ret) {
+ dev_err(dev, "can't reset resource table: %d\n", ret);
+ return ret;
+ }
/* power off the remote processor */
ret = rproc->ops->stop(rproc);
@@ -1721,6 +1813,9 @@ static int __rproc_detach(struct rproc *rproc)
/* Stop any subdevices for the remote processor */
rproc_stop_subdevices(rproc, false);
+ /* The installed resource table need to be reset and no longer accessible */
+ ret = rproc_reset_loaded_rsc_table(rproc);
+
/* Tell the remote processor the core isn't available anymore */
ret = rproc->ops->detach(rproc);
if (ret) {
@@ -1941,6 +2036,7 @@ void rproc_shutdown(struct rproc *rproc)
/* Free the copy of the resource table */
kfree(rproc->cached_table);
+ kfree(rproc->clean_table);
rproc->cached_table = NULL;
rproc->table_ptr = NULL;
out:
@@ -1997,6 +2093,9 @@ int rproc_detach(struct rproc *rproc)
rproc_disable_iommu(rproc);
+ /* Free the copy of the resource table */
+ kfree(rproc->cached_table);
+ rproc->cached_table = NULL;
rproc->table_ptr = NULL;
out:
mutex_unlock(&rproc->lock);
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index e1c843c19cc6..e5f52a12a650 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -514,6 +514,8 @@ struct rproc_dump_segment {
* @recovery_disabled: flag that state if recovery was disabled
* @max_notifyid: largest allocated notify id.
* @table_ptr: pointer to the resource table in effect
+ * @clean_table: copy of the resource table without modifications. Used
+ * when a remote processor is attached or detached from the core
* @cached_table: copy of the resource table
* @table_sz: size of @cached_table
* @has_iommu: flag to indicate if remote processor is behind an MMU
@@ -550,6 +552,7 @@ struct rproc {
bool recovery_disabled;
int max_notifyid;
struct resource_table *table_ptr;
+ struct resource_table *clean_table;
struct resource_table *cached_table;
size_t table_sz;
bool has_iommu;
--