From Android R onwards Google has restricted access to debugfs in user
and user-debug builds. This restricts access to most of the features
exposed through debugfs. This patch series removes the recovery/coredump
entries from debugfs and moves them to sysfs.
'Coredump' and 'Recovery' are critical interfaces that are required
for remoteproc to work on Qualcomm Chipsets. Coredump configuration
needs to be set to "inline" in debug/test build and "disabled" in
production builds. Whereas recovery needs to be "disabled" for
debugging purposes and "enabled" on production builds.
Changelog:
v5 -> v4:
- Fix the cover-letter of tha patch series.
v4 -> v3:
- Remove the feature flag to expose recovery/coredump
v3 -> v2:
- Remove the coredump/recovery entries from debugfs
- Expose recovery/coredump from sysfs under a feature flag
v1 -> v2:
- Correct the contact name in the sysfs documentation.
- Remove the redundant write documentation for coredump/recovery sysfs
- Add a feature flag to make this interface switch configurable.
Rishabh Bhatnagar (2):
remoteproc: Move coredump configuration to sysfs
remoteproc: Move recovery configuration to sysfs
Documentation/ABI/testing/sysfs-class-remoteproc | 44 ++++++
drivers/remoteproc/remoteproc_debugfs.c | 168 -----------------------
drivers/remoteproc/remoteproc_sysfs.c | 120 ++++++++++++++++
3 files changed, 164 insertions(+), 168 deletions(-)
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
Move coredump configuration from debugfs to sysfs.This will
allow usage of this configuration feature in production
devices where access to debugfs might be limited.
Signed-off-by: Rishabh Bhatnagar <[email protected]>
---
Documentation/ABI/testing/sysfs-class-remoteproc | 24 +++++++
drivers/remoteproc/remoteproc_debugfs.c | 90 ------------------------
drivers/remoteproc/remoteproc_sysfs.c | 64 +++++++++++++++++
3 files changed, 88 insertions(+), 90 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-class-remoteproc b/Documentation/ABI/testing/sysfs-class-remoteproc
index 36094fb..f6c44fa 100644
--- a/Documentation/ABI/testing/sysfs-class-remoteproc
+++ b/Documentation/ABI/testing/sysfs-class-remoteproc
@@ -58,3 +58,27 @@ Description: Remote processor name
Reports the name of the remote processor. This can be used by
userspace in exactly identifying a remote processor and ease
up the usage in modifying the 'firmware' or 'state' files.
+
+What: /sys/class/remoteproc/.../coredump
+Date: July 2020
+Contact: Bjorn Andersson <[email protected]>, Ohad Ben-Cohen <[email protected]>
+Description: Remote processor coredump configuration
+
+ Reports the coredump configuration of the remote processor,
+ which will be one of:
+
+ "default"
+ "inline"
+ "disabled"
+
+ "default" means when the remote processor's coredump is
+ collected it will be copied to a separate buffer and that
+ buffer is exposed to userspace.
+
+ "inline" means when the remote processor's coredump is
+ collected userspace will directly read from the remote
+ processor's device memory. Extra buffer will not be used to
+ copy the dump. Also recovery process will not proceed until
+ all data is read by usersapce.
+
+ "disabled" means no dump will be collected.
diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
index 2e3b3e2..732770e 100644
--- a/drivers/remoteproc/remoteproc_debugfs.c
+++ b/drivers/remoteproc/remoteproc_debugfs.c
@@ -28,94 +28,6 @@
static struct dentry *rproc_dbg;
/*
- * A coredump-configuration-to-string lookup table, for exposing a
- * human readable configuration via debugfs. Always keep in sync with
- * enum rproc_coredump_mechanism
- */
-static const char * const rproc_coredump_str[] = {
- [RPROC_COREDUMP_DEFAULT] = "default",
- [RPROC_COREDUMP_INLINE] = "inline",
- [RPROC_COREDUMP_DISABLED] = "disabled",
-};
-
-/* Expose the current coredump configuration via debugfs */
-static ssize_t rproc_coredump_read(struct file *filp, char __user *userbuf,
- size_t count, loff_t *ppos)
-{
- struct rproc *rproc = filp->private_data;
- char buf[20];
- int len;
-
- len = scnprintf(buf, sizeof(buf), "%s\n",
- rproc_coredump_str[rproc->dump_conf]);
-
- return simple_read_from_buffer(userbuf, count, ppos, buf, len);
-}
-
-/*
- * By writing to the 'coredump' debugfs entry, we control the behavior of the
- * coredump mechanism dynamically. The default value of this entry is "default".
- *
- * The 'coredump' debugfs entry supports these commands:
- *
- * default: This is the default coredump mechanism. When the remoteproc
- * crashes the entire coredump will be copied to a separate buffer
- * and exposed to userspace.
- *
- * inline: The coredump will not be copied to a separate buffer and the
- * recovery process will have to wait until data is read by
- * userspace. But this avoid usage of extra memory.
- *
- * disabled: This will disable coredump. Recovery will proceed without
- * collecting any dump.
- */
-static ssize_t rproc_coredump_write(struct file *filp,
- const char __user *user_buf, size_t count,
- loff_t *ppos)
-{
- struct rproc *rproc = filp->private_data;
- int ret, err = 0;
- char buf[20];
-
- if (count > sizeof(buf))
- return -EINVAL;
-
- ret = copy_from_user(buf, user_buf, count);
- if (ret)
- return -EFAULT;
-
- /* remove end of line */
- if (buf[count - 1] == '\n')
- buf[count - 1] = '\0';
-
- if (rproc->state == RPROC_CRASHED) {
- dev_err(&rproc->dev, "can't change coredump configuration\n");
- err = -EBUSY;
- goto out;
- }
-
- if (!strncmp(buf, "disable", count)) {
- rproc->dump_conf = RPROC_COREDUMP_DISABLED;
- } else if (!strncmp(buf, "inline", count)) {
- rproc->dump_conf = RPROC_COREDUMP_INLINE;
- } else if (!strncmp(buf, "default", count)) {
- rproc->dump_conf = RPROC_COREDUMP_DEFAULT;
- } else {
- dev_err(&rproc->dev, "Invalid coredump configuration\n");
- err = -EINVAL;
- }
-out:
- return err ? err : count;
-}
-
-static const struct file_operations rproc_coredump_fops = {
- .read = rproc_coredump_read,
- .write = rproc_coredump_write,
- .open = simple_open,
- .llseek = generic_file_llseek,
-};
-
-/*
* Some remote processors may support dumping trace logs into a shared
* memory buffer. We expose this trace buffer using debugfs, so users
* can easily tell what's going on remotely.
@@ -425,8 +337,6 @@ void rproc_create_debug_dir(struct rproc *rproc)
rproc, &rproc_rsc_table_fops);
debugfs_create_file("carveout_memories", 0400, rproc->dbg_dir,
rproc, &rproc_carveouts_fops);
- debugfs_create_file("coredump", 0600, rproc->dbg_dir,
- rproc, &rproc_coredump_fops);
}
void __init rproc_init_debugfs(void)
diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
index eea514c..40949a0 100644
--- a/drivers/remoteproc/remoteproc_sysfs.c
+++ b/drivers/remoteproc/remoteproc_sysfs.c
@@ -10,6 +10,69 @@
#define to_rproc(d) container_of(d, struct rproc, dev)
+/*
+ * A coredump-configuration-to-string lookup table, for exposing a
+ * human readable configuration via sysfs. Always keep in sync with
+ * enum rproc_coredump_mechanism
+ */
+static const char * const rproc_coredump_str[] = {
+ [RPROC_COREDUMP_DEFAULT] = "default",
+ [RPROC_COREDUMP_INLINE] = "inline",
+ [RPROC_COREDUMP_DISABLED] = "disabled",
+};
+
+/* Expose the current coredump configuration via debugfs */
+static ssize_t coredump_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct rproc *rproc = to_rproc(dev);
+
+ return sprintf(buf, "%s\n", rproc_coredump_str[rproc->dump_conf]);
+}
+
+/*
+ * By writing to the 'coredump' sysfs entry, we control the behavior of the
+ * coredump mechanism dynamically. The default value of this entry is "default".
+ *
+ * The 'coredump' sysfs entry supports these commands:
+ *
+ * default: This is the default coredump mechanism. When the remoteproc
+ * crashes the entire coredump will be copied to a separate buffer
+ * and exposed to userspace.
+ *
+ * inline: The coredump will not be copied to a separate buffer and the
+ * recovery process will have to wait until data is read by
+ * userspace. But this avoid usage of extra memory.
+ *
+ * disabled: This will disable coredump. Recovery will proceed without
+ * collecting any dump.
+ */
+static ssize_t coredump_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct rproc *rproc = to_rproc(dev);
+
+ if (rproc->state == RPROC_CRASHED) {
+ dev_err(&rproc->dev, "can't change coredump configuration\n");
+ return -EBUSY;
+ }
+
+ if (sysfs_streq(buf, "disable")) {
+ rproc->dump_conf = RPROC_COREDUMP_DISABLED;
+ } else if (sysfs_streq(buf, "inline")) {
+ rproc->dump_conf = RPROC_COREDUMP_INLINE;
+ } else if (sysfs_streq(buf, "default")) {
+ rproc->dump_conf = RPROC_COREDUMP_DEFAULT;
+ } else {
+ dev_err(&rproc->dev, "Invalid coredump configuration\n");
+ return -EINVAL;
+ }
+
+ return count;
+}
+static DEVICE_ATTR_RW(coredump);
+
/* Expose the loaded / running firmware name via sysfs */
static ssize_t firmware_show(struct device *dev, struct device_attribute *attr,
char *buf)
@@ -138,6 +201,7 @@ static ssize_t name_show(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR_RO(name);
static struct attribute *rproc_attrs[] = {
+ &dev_attr_coredump.attr,
&dev_attr_firmware.attr,
&dev_attr_state.attr,
&dev_attr_name.attr,
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
On Fri 18 Sep 10:22 PDT 2020, Rishabh Bhatnagar wrote:
> diff --git a/drivers/remoteproc/remoteproc_debugfs.c b/drivers/remoteproc/remoteproc_debugfs.c
[..]
> +static ssize_t coredump_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct rproc *rproc = to_rproc(dev);
> +
> + if (rproc->state == RPROC_CRASHED) {
> + dev_err(&rproc->dev, "can't change coredump configuration\n");
> + return -EBUSY;
> + }
> +
> + if (sysfs_streq(buf, "disable")) {
As pointed out by Sibi (somewhere) this should be "disabled" to match
what's returned in coredump_show() and what goes into the recovery
file.
> + rproc->dump_conf = RPROC_COREDUMP_DISABLED;
> + } else if (sysfs_streq(buf, "inline")) {
> + rproc->dump_conf = RPROC_COREDUMP_INLINE;
> + } else if (sysfs_streq(buf, "default")) {
As I pointed out in a previous review, I think it makes sense to change
the default for dump_conf to "disabled" (a separate change). But in
doing so using the word "default" in the sysfs interface would be
misleading - and once it's part of sysfs it stays.
So how about changing this to "enabled"?
PS. The change of the default value of dump_conf would, in line with
Mathieu's ask, be a separate/unrelated change.
Regards,
Bjorn