[PATCH v5 1/2] remoteproc: Move coredump configuration to sysfs

Rishabh Bhatnagar
2020-09-18T17:22:27Z

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 <rishabhb@codeaurora.org>
---
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 <bjorn.andersson@linaro.org>, Ohad Ben-Cohen <ohad@wizery.com>
+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,