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remoteproc: create a 'recovery' debugfs entry
Add a 'recovery' debugfs entry to dynamically disable/enable recovery at runtime. This is useful when one is trying to debug an rproc crash; without it, a recovery will immediately take place, making it harder to debug the crash. Contributions from Subramaniam Chanderashekarapuram. Examples: - disabling recovery: $ echo disabled > <debugfs>/remoteproc/remoteproc0/recovery - in case you want to recover a crash, but keep recovery disabled (useful in debugging sessions when you expect additional crashes you want to debug): $ echo recover > <debugfs>/remoteproc/remoteproc0/recovery - enabling recovery: $ echo enabled > <debugfs>/remoteproc/remoteproc0/recovery Signed-off-by: Fernando Guzman Lugo <fernando.lugo@ti.com> [ohad: some white space, commentary and commit log changes] Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
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3 changed files with 85 additions and 1 deletions
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@ -965,7 +965,8 @@ static void rproc_crash_handler_work(struct work_struct *work)
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mutex_unlock(&rproc->lock);
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rproc_trigger_recovery(rproc);
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if (!rproc->recovery_disabled)
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rproc_trigger_recovery(rproc);
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}
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/**
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@ -28,6 +28,9 @@
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#include <linux/debugfs.h>
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#include <linux/remoteproc.h>
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#include <linux/device.h>
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#include <linux/uaccess.h>
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#include "remoteproc_internal.h"
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/* remoteproc debugfs parent dir */
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static struct dentry *rproc_dbg;
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@ -111,6 +114,82 @@ static const struct file_operations rproc_name_ops = {
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.llseek = generic_file_llseek,
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};
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/* expose recovery flag via debugfs */
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static ssize_t rproc_recovery_read(struct file *filp, char __user *userbuf,
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size_t count, loff_t *ppos)
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{
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struct rproc *rproc = filp->private_data;
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char *buf = rproc->recovery_disabled ? "disabled\n" : "enabled\n";
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return simple_read_from_buffer(userbuf, count, ppos, buf, strlen(buf));
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}
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/*
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* By writing to the 'recovery' debugfs entry, we control the behavior of the
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* recovery mechanism dynamically. The default value of this entry is "enabled".
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*
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* The 'recovery' debugfs entry supports these commands:
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*
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* enabled: When enabled, the remote processor will be automatically
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* recovered whenever it crashes. Moreover, if the remote
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* processor crashes while recovery is disabled, it will
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* be automatically recovered too as soon as recovery is enabled.
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*
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* disabled: When disabled, a remote processor will remain in a crashed
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* state if it crashes. This is useful for debugging purposes;
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* without it, debugging a crash is substantially harder.
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*
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* recover: This function will trigger an immediate recovery if the
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* remote processor is in a crashed state, without changing
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* or checking the recovery state (enabled/disabled).
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* This is useful during debugging sessions, when one expects
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* additional crashes to happen after enabling recovery. In this
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* case, enabling recovery will make it hard to debug subsequent
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* crashes, so it's recommended to keep recovery disabled, and
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* instead use the "recover" command as needed.
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*/
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static ssize_t
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rproc_recovery_write(struct file *filp, const char __user *user_buf,
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size_t count, loff_t *ppos)
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{
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struct rproc *rproc = filp->private_data;
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char buf[10];
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int ret;
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if (count > sizeof(buf))
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return count;
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ret = copy_from_user(buf, user_buf, count);
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if (ret)
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return ret;
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/* remove end of line */
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if (buf[count - 1] == '\n')
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buf[count - 1] = '\0';
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if (!strncmp(buf, "enabled", count)) {
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rproc->recovery_disabled = false;
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/* if rproc has crashed, trigger recovery */
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if (rproc->state == RPROC_CRASHED)
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rproc_trigger_recovery(rproc);
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} else if (!strncmp(buf, "disabled", count)) {
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rproc->recovery_disabled = true;
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} else if (!strncmp(buf, "recover", count)) {
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/* if rproc has crashed, trigger recovery */
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if (rproc->state == RPROC_CRASHED)
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rproc_trigger_recovery(rproc);
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}
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return count;
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}
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static const struct file_operations rproc_recovery_ops = {
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.read = rproc_recovery_read,
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.write = rproc_recovery_write,
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.open = simple_open,
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.llseek = generic_file_llseek,
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};
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void rproc_remove_trace_file(struct dentry *tfile)
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{
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debugfs_remove(tfile);
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@ -154,6 +233,8 @@ void rproc_create_debug_dir(struct rproc *rproc)
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rproc, &rproc_name_ops);
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debugfs_create_file("state", 0400, rproc->dbg_dir,
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rproc, &rproc_state_ops);
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debugfs_create_file("recovery", 0400, rproc->dbg_dir,
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rproc, &rproc_recovery_ops);
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}
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void __init rproc_init_debugfs(void)
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@ -399,6 +399,7 @@ enum rproc_crash_type {
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* @crash_handler: workqueue for handling a crash
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* @crash_cnt: crash counter
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* @crash_comp: completion used to sync crash handler and the rproc reload
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* @recovery_disabled: flag that state if recovery was disabled
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*/
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struct rproc {
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struct klist_node node;
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@ -425,6 +426,7 @@ struct rproc {
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struct work_struct crash_handler;
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unsigned crash_cnt;
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struct completion crash_comp;
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bool recovery_disabled;
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};
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/* we currently support only two vrings per rvdev */
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