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bec109a430
copy_from_user() returns the number of bytes remaining to be copied, but we want to return an error code here. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
254 lines
7.1 KiB
C
254 lines
7.1 KiB
C
/*
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* Remote Processor Framework
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*
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* Copyright (C) 2011 Texas Instruments, Inc.
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* Copyright (C) 2011 Google, Inc.
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*
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* Ohad Ben-Cohen <ohad@wizery.com>
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* Mark Grosen <mgrosen@ti.com>
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* Brian Swetland <swetland@google.com>
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* Fernando Guzman Lugo <fernando.lugo@ti.com>
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* Suman Anna <s-anna@ti.com>
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* Robert Tivy <rtivy@ti.com>
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* Armando Uribe De Leon <x0095078@ti.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* version 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#define pr_fmt(fmt) "%s: " fmt, __func__
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#include <linux/kernel.h>
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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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/*
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* Some remote processors may support dumping trace logs into a shared
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* memory buffer. We expose this trace buffer using debugfs, so users
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* can easily tell what's going on remotely.
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*
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* We will most probably improve the rproc tracing facilities later on,
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* but this kind of lightweight and simple mechanism is always good to have,
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* as it provides very early tracing with little to no dependencies at all.
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*/
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static ssize_t rproc_trace_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_mem_entry *trace = filp->private_data;
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int len = strnlen(trace->va, trace->len);
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return simple_read_from_buffer(userbuf, count, ppos, trace->va, len);
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}
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static const struct file_operations trace_rproc_ops = {
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.read = rproc_trace_read,
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.open = simple_open,
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.llseek = generic_file_llseek,
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};
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/*
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* A state-to-string lookup table, for exposing a human readable state
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* via debugfs. Always keep in sync with enum rproc_state
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*/
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static const char * const rproc_state_string[] = {
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"offline",
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"suspended",
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"running",
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"crashed",
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"invalid",
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};
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/* expose the state of the remote processor via debugfs */
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static ssize_t rproc_state_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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unsigned int state;
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char buf[30];
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int i;
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state = rproc->state > RPROC_LAST ? RPROC_LAST : rproc->state;
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i = scnprintf(buf, 30, "%.28s (%d)\n", rproc_state_string[state],
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rproc->state);
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return simple_read_from_buffer(userbuf, count, ppos, buf, i);
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}
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static const struct file_operations rproc_state_ops = {
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.read = rproc_state_read,
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.open = simple_open,
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.llseek = generic_file_llseek,
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};
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/* expose the name of the remote processor via debugfs */
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static ssize_t rproc_name_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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/* need room for the name, a newline and a terminating null */
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char buf[100];
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int i;
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i = scnprintf(buf, sizeof(buf), "%.98s\n", rproc->name);
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return simple_read_from_buffer(userbuf, count, ppos, buf, i);
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}
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static const struct file_operations rproc_name_ops = {
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.read = rproc_name_read,
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.open = simple_open,
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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 -EFAULT;
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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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}
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struct dentry *rproc_create_trace_file(const char *name, struct rproc *rproc,
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struct rproc_mem_entry *trace)
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{
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struct dentry *tfile;
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tfile = debugfs_create_file(name, 0400, rproc->dbg_dir,
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trace, &trace_rproc_ops);
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if (!tfile) {
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dev_err(&rproc->dev, "failed to create debugfs trace entry\n");
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return NULL;
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}
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return tfile;
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}
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void rproc_delete_debug_dir(struct rproc *rproc)
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{
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if (!rproc->dbg_dir)
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return;
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debugfs_remove_recursive(rproc->dbg_dir);
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}
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void rproc_create_debug_dir(struct rproc *rproc)
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{
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struct device *dev = &rproc->dev;
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if (!rproc_dbg)
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return;
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rproc->dbg_dir = debugfs_create_dir(dev_name(dev), rproc_dbg);
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if (!rproc->dbg_dir)
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return;
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debugfs_create_file("name", 0400, rproc->dbg_dir,
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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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{
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if (debugfs_initialized()) {
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rproc_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
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if (!rproc_dbg)
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pr_err("can't create debugfs dir\n");
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}
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}
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void __exit rproc_exit_debugfs(void)
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{
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if (rproc_dbg)
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debugfs_remove(rproc_dbg);
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}
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