android_kernel_xiaomi_sm8350/arch/um/drivers/mconsole_kern.c
Jeff Dike 3eddddcf23 [PATCH] uml: breakpoint an arbitrary thread
This patch implements a stack trace for a thread, not unlike sysrq-t does.
The advantage to this is that a break point can be placed on showreqs, so that
upon showing the stack, you jump immediately into the debugger.  While sysrq-t
does the same thing, sysrq-t shows *all* threads stacks.  It also doesn't work
right now.  In the future, I thought it might be acceptable to make this show
all pids stacks, but perhaps leaving well enough alone and just using sysrq-t
would be okay.  For now, upon receiving the stack command, UML switches
context to that thread, dumps its registers, and then switches context back to
the original thread.  Since UML compacts all threads into one of 4 host
threads, this sort of mechanism could be expanded in the future to include
other debugging helpers that sysrq does not cover.

Note by jdike - The main benefit to this is that it brings an arbitrary thread
back into context, where it can be examined by gdb.  The fact that it dumps it
stack is secondary.  This provides the capability to examine a sleeping
thread, which has existed in tt mode, but not in skas mode until now.

Also, the other threads, that sysrq doesn't cover, can be gdb-ed directly
anyway.

Signed-off-by: Allan Graves<allan.graves@gmail.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-17 11:49:59 -07:00

700 lines
16 KiB
C

/*
* Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
* Copyright (C) 2001 - 2003 Jeff Dike (jdike@addtoit.com)
* Licensed under the GPL
*/
#include "linux/kernel.h"
#include "linux/slab.h"
#include "linux/init.h"
#include "linux/notifier.h"
#include "linux/reboot.h"
#include "linux/utsname.h"
#include "linux/ctype.h"
#include "linux/interrupt.h"
#include "linux/sysrq.h"
#include "linux/workqueue.h"
#include "linux/module.h"
#include "linux/file.h"
#include "linux/fs.h"
#include "linux/namei.h"
#include "linux/proc_fs.h"
#include "linux/syscalls.h"
#include "asm/irq.h"
#include "asm/uaccess.h"
#include "user_util.h"
#include "kern_util.h"
#include "kern.h"
#include "mconsole.h"
#include "mconsole_kern.h"
#include "irq_user.h"
#include "init.h"
#include "os.h"
#include "umid.h"
#include "irq_kern.h"
#include "choose-mode.h"
static int do_unlink_socket(struct notifier_block *notifier,
unsigned long what, void *data)
{
return(mconsole_unlink_socket());
}
static struct notifier_block reboot_notifier = {
.notifier_call = do_unlink_socket,
.priority = 0,
};
/* Safe without explicit locking for now. Tasklets provide their own
* locking, and the interrupt handler is safe because it can't interrupt
* itself and it can only happen on CPU 0.
*/
LIST_HEAD(mc_requests);
static void mc_work_proc(void *unused)
{
struct mconsole_entry *req;
unsigned long flags;
while(!list_empty(&mc_requests)){
local_save_flags(flags);
req = list_entry(mc_requests.next, struct mconsole_entry,
list);
list_del(&req->list);
local_irq_restore(flags);
req->request.cmd->handler(&req->request);
kfree(req);
}
}
DECLARE_WORK(mconsole_work, mc_work_proc, NULL);
static irqreturn_t mconsole_interrupt(int irq, void *dev_id,
struct pt_regs *regs)
{
/* long to avoid size mismatch warnings from gcc */
long fd;
struct mconsole_entry *new;
struct mc_request req;
fd = (long) dev_id;
while (mconsole_get_request(fd, &req)){
if(req.cmd->context == MCONSOLE_INTR)
(*req.cmd->handler)(&req);
else {
new = kmalloc(sizeof(*new), GFP_ATOMIC);
if(new == NULL)
mconsole_reply(&req, "Out of memory", 1, 0);
else {
new->request = req;
list_add(&new->list, &mc_requests);
}
}
}
if(!list_empty(&mc_requests))
schedule_work(&mconsole_work);
reactivate_fd(fd, MCONSOLE_IRQ);
return(IRQ_HANDLED);
}
void mconsole_version(struct mc_request *req)
{
char version[256];
sprintf(version, "%s %s %s %s %s", system_utsname.sysname,
system_utsname.nodename, system_utsname.release,
system_utsname.version, system_utsname.machine);
mconsole_reply(req, version, 0, 0);
}
void mconsole_log(struct mc_request *req)
{
int len;
char *ptr = req->request.data;
ptr += strlen("log ");
len = req->len - (ptr - req->request.data);
printk("%.*s", len, ptr);
mconsole_reply(req, "", 0, 0);
}
/* This is a more convoluted version of mconsole_proc, which has some stability
* problems; however, we need it fixed, because it is expected that UML users
* mount HPPFS instead of procfs on /proc. And we want mconsole_proc to still
* show the real procfs content, not the ones from hppfs.*/
#if 0
void mconsole_proc(struct mc_request *req)
{
struct nameidata nd;
struct file_system_type *proc;
struct super_block *super;
struct file *file;
int n, err;
char *ptr = req->request.data, *buf;
ptr += strlen("proc");
while(isspace(*ptr)) ptr++;
proc = get_fs_type("proc");
if(proc == NULL){
mconsole_reply(req, "procfs not registered", 1, 0);
goto out;
}
super = (*proc->get_sb)(proc, 0, NULL, NULL);
put_filesystem(proc);
if(super == NULL){
mconsole_reply(req, "Failed to get procfs superblock", 1, 0);
goto out;
}
up_write(&super->s_umount);
nd.dentry = super->s_root;
nd.mnt = NULL;
nd.flags = O_RDONLY + 1;
nd.last_type = LAST_ROOT;
/* START: it was experienced that the stability problems are closed
* if commenting out these two calls + the below read cycle. To
* make UML crash again, it was enough to readd either one.*/
err = link_path_walk(ptr, &nd);
if(err){
mconsole_reply(req, "Failed to look up file", 1, 0);
goto out_kill;
}
file = dentry_open(nd.dentry, nd.mnt, O_RDONLY);
if(IS_ERR(file)){
mconsole_reply(req, "Failed to open file", 1, 0);
goto out_kill;
}
/*END*/
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if(buf == NULL){
mconsole_reply(req, "Failed to allocate buffer", 1, 0);
goto out_fput;
}
if((file->f_op != NULL) && (file->f_op->read != NULL)){
do {
n = (*file->f_op->read)(file, buf, PAGE_SIZE - 1,
&file->f_pos);
if(n >= 0){
buf[n] = '\0';
mconsole_reply(req, buf, 0, (n > 0));
}
else {
mconsole_reply(req, "Read of file failed",
1, 0);
goto out_free;
}
} while(n > 0);
}
else mconsole_reply(req, "", 0, 0);
out_free:
kfree(buf);
out_fput:
fput(file);
out_kill:
deactivate_super(super);
out: ;
}
#endif
void mconsole_proc(struct mc_request *req)
{
char path[64];
char *buf;
int len;
int fd;
int first_chunk = 1;
char *ptr = req->request.data;
ptr += strlen("proc");
while(isspace(*ptr)) ptr++;
snprintf(path, sizeof(path), "/proc/%s", ptr);
fd = sys_open(path, 0, 0);
if (fd < 0) {
mconsole_reply(req, "Failed to open file", 1, 0);
printk("open %s: %d\n",path,fd);
goto out;
}
buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
if(buf == NULL){
mconsole_reply(req, "Failed to allocate buffer", 1, 0);
goto out_close;
}
for (;;) {
len = sys_read(fd, buf, PAGE_SIZE-1);
if (len < 0) {
mconsole_reply(req, "Read of file failed", 1, 0);
goto out_free;
}
/*Begin the file content on his own line.*/
if (first_chunk) {
mconsole_reply(req, "\n", 0, 1);
first_chunk = 0;
}
if (len == PAGE_SIZE-1) {
buf[len] = '\0';
mconsole_reply(req, buf, 0, 1);
} else {
buf[len] = '\0';
mconsole_reply(req, buf, 0, 0);
break;
}
}
out_free:
kfree(buf);
out_close:
sys_close(fd);
out:
/* nothing */;
}
#define UML_MCONSOLE_HELPTEXT \
"Commands: \n\
version - Get kernel version \n\
help - Print this message \n\
halt - Halt UML \n\
reboot - Reboot UML \n\
config <dev>=<config> - Add a new device to UML; \n\
same syntax as command line \n\
config <dev> - Query the configuration of a device \n\
remove <dev> - Remove a device from UML \n\
sysrq <letter> - Performs the SysRq action controlled by the letter \n\
cad - invoke the Ctl-Alt-Del handler \n\
stop - pause the UML; it will do nothing until it receives a 'go' \n\
go - continue the UML after a 'stop' \n\
log <string> - make UML enter <string> into the kernel log\n\
proc <file> - returns the contents of the UML's /proc/<file>\n\
stack <pid> - returns the stack of the specified pid\n\
"
void mconsole_help(struct mc_request *req)
{
mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
}
void mconsole_halt(struct mc_request *req)
{
mconsole_reply(req, "", 0, 0);
machine_halt();
}
void mconsole_reboot(struct mc_request *req)
{
mconsole_reply(req, "", 0, 0);
machine_restart(NULL);
}
extern void ctrl_alt_del(void);
void mconsole_cad(struct mc_request *req)
{
mconsole_reply(req, "", 0, 0);
ctrl_alt_del();
}
void mconsole_go(struct mc_request *req)
{
mconsole_reply(req, "Not stopped", 1, 0);
}
void mconsole_stop(struct mc_request *req)
{
deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
os_set_fd_block(req->originating_fd, 1);
mconsole_reply(req, "", 0, 0);
while(mconsole_get_request(req->originating_fd, req)){
if(req->cmd->handler == mconsole_go) break;
(*req->cmd->handler)(req);
}
os_set_fd_block(req->originating_fd, 0);
reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
mconsole_reply(req, "", 0, 0);
}
/* This list is populated by __initcall routines. */
LIST_HEAD(mconsole_devices);
void mconsole_register_dev(struct mc_device *new)
{
list_add(&new->list, &mconsole_devices);
}
static struct mc_device *mconsole_find_dev(char *name)
{
struct list_head *ele;
struct mc_device *dev;
list_for_each(ele, &mconsole_devices){
dev = list_entry(ele, struct mc_device, list);
if(!strncmp(name, dev->name, strlen(dev->name)))
return(dev);
}
return(NULL);
}
#define CONFIG_BUF_SIZE 64
static void mconsole_get_config(int (*get_config)(char *, char *, int,
char **),
struct mc_request *req, char *name)
{
char default_buf[CONFIG_BUF_SIZE], *error, *buf;
int n, size;
if(get_config == NULL){
mconsole_reply(req, "No get_config routine defined", 1, 0);
return;
}
error = NULL;
size = sizeof(default_buf)/sizeof(default_buf[0]);
buf = default_buf;
while(1){
n = (*get_config)(name, buf, size, &error);
if(error != NULL){
mconsole_reply(req, error, 1, 0);
goto out;
}
if(n <= size){
mconsole_reply(req, buf, 0, 0);
goto out;
}
if(buf != default_buf)
kfree(buf);
size = n;
buf = kmalloc(size, GFP_KERNEL);
if(buf == NULL){
mconsole_reply(req, "Failed to allocate buffer", 1, 0);
return;
}
}
out:
if(buf != default_buf)
kfree(buf);
}
void mconsole_config(struct mc_request *req)
{
struct mc_device *dev;
char *ptr = req->request.data, *name;
int err;
ptr += strlen("config");
while(isspace(*ptr)) ptr++;
dev = mconsole_find_dev(ptr);
if(dev == NULL){
mconsole_reply(req, "Bad configuration option", 1, 0);
return;
}
name = &ptr[strlen(dev->name)];
ptr = name;
while((*ptr != '=') && (*ptr != '\0'))
ptr++;
if(*ptr == '='){
err = (*dev->config)(name);
mconsole_reply(req, "", err, 0);
}
else mconsole_get_config(dev->get_config, req, name);
}
void mconsole_remove(struct mc_request *req)
{
struct mc_device *dev;
char *ptr = req->request.data, *err_msg = "";
char error[256];
int err, start, end, n;
ptr += strlen("remove");
while(isspace(*ptr)) ptr++;
dev = mconsole_find_dev(ptr);
if(dev == NULL){
mconsole_reply(req, "Bad remove option", 1, 0);
return;
}
ptr = &ptr[strlen(dev->name)];
err = 1;
n = (*dev->id)(&ptr, &start, &end);
if(n < 0){
err_msg = "Couldn't parse device number";
goto out;
}
else if((n < start) || (n > end)){
sprintf(error, "Invalid device number - must be between "
"%d and %d", start, end);
err_msg = error;
goto out;
}
err = (*dev->remove)(n);
switch(err){
case -ENODEV:
err_msg = "Device doesn't exist";
break;
case -EBUSY:
err_msg = "Device is currently open";
break;
default:
break;
}
out:
mconsole_reply(req, err_msg, err, 0);
}
#ifdef CONFIG_MAGIC_SYSRQ
void mconsole_sysrq(struct mc_request *req)
{
char *ptr = req->request.data;
ptr += strlen("sysrq");
while(isspace(*ptr)) ptr++;
mconsole_reply(req, "", 0, 0);
handle_sysrq(*ptr, &current->thread.regs, NULL);
}
#else
void mconsole_sysrq(struct mc_request *req)
{
mconsole_reply(req, "Sysrq not compiled in", 1, 0);
}
#endif
/* Mconsole stack trace
* Added by Allan Graves, Jeff Dike
* Dumps a stacks registers to the linux console.
* Usage stack <pid>.
*/
void do_stack(struct mc_request *req)
{
char *ptr = req->request.data;
int pid_requested= -1;
struct task_struct *from = NULL;
struct task_struct *to = NULL;
/* Would be nice:
* 1) Send showregs output to mconsole.
* 2) Add a way to stack dump all pids.
*/
ptr += strlen("stack");
while(isspace(*ptr)) ptr++;
/* Should really check for multiple pids or reject bad args here */
/* What do the arguments in mconsole_reply mean? */
if(sscanf(ptr, "%d", &pid_requested) == 0){
mconsole_reply(req, "Please specify a pid", 1, 0);
return;
}
from = current;
to = find_task_by_pid(pid_requested);
if((to == NULL) || (pid_requested == 0)) {
mconsole_reply(req, "Couldn't find that pid", 1, 0);
return;
}
to->thread.saved_task = current;
switch_to(from, to, from);
mconsole_reply(req, "Stack Dumped to console and message log", 0, 0);
}
void mconsole_stack(struct mc_request *req)
{
/* This command doesn't work in TT mode, so let's check and then
* get out of here
*/
CHOOSE_MODE(mconsole_reply(req, "Sorry, this doesn't work in TT mode",
1, 0),
do_stack(req));
}
/* Changed by mconsole_setup, which is __setup, and called before SMP is
* active.
*/
static char *notify_socket = NULL;
int mconsole_init(void)
{
/* long to avoid size mismatch warnings from gcc */
long sock;
int err;
char file[256];
if(umid_file_name("mconsole", file, sizeof(file))) return(-1);
snprintf(mconsole_socket_name, sizeof(file), "%s", file);
sock = os_create_unix_socket(file, sizeof(file), 1);
if (sock < 0){
printk("Failed to initialize management console\n");
return(1);
}
register_reboot_notifier(&reboot_notifier);
err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
SA_INTERRUPT | SA_SHIRQ | SA_SAMPLE_RANDOM,
"mconsole", (void *)sock);
if (err){
printk("Failed to get IRQ for management console\n");
return(1);
}
if(notify_socket != NULL){
notify_socket = uml_strdup(notify_socket);
if(notify_socket != NULL)
mconsole_notify(notify_socket, MCONSOLE_SOCKET,
mconsole_socket_name,
strlen(mconsole_socket_name) + 1);
else printk(KERN_ERR "mconsole_setup failed to strdup "
"string\n");
}
printk("mconsole (version %d) initialized on %s\n",
MCONSOLE_VERSION, mconsole_socket_name);
return(0);
}
__initcall(mconsole_init);
static int write_proc_mconsole(struct file *file, const char __user *buffer,
unsigned long count, void *data)
{
char *buf;
buf = kmalloc(count + 1, GFP_KERNEL);
if(buf == NULL)
return(-ENOMEM);
if(copy_from_user(buf, buffer, count)){
count = -EFAULT;
goto out;
}
buf[count] = '\0';
mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
out:
kfree(buf);
return(count);
}
static int create_proc_mconsole(void)
{
struct proc_dir_entry *ent;
if(notify_socket == NULL) return(0);
ent = create_proc_entry("mconsole", S_IFREG | 0200, NULL);
if(ent == NULL){
printk(KERN_INFO "create_proc_mconsole : create_proc_entry failed\n");
return(0);
}
ent->read_proc = NULL;
ent->write_proc = write_proc_mconsole;
return(0);
}
static DEFINE_SPINLOCK(notify_spinlock);
void lock_notify(void)
{
spin_lock(&notify_spinlock);
}
void unlock_notify(void)
{
spin_unlock(&notify_spinlock);
}
__initcall(create_proc_mconsole);
#define NOTIFY "=notify:"
static int mconsole_setup(char *str)
{
if(!strncmp(str, NOTIFY, strlen(NOTIFY))){
str += strlen(NOTIFY);
notify_socket = str;
}
else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
return(1);
}
__setup("mconsole", mconsole_setup);
__uml_help(mconsole_setup,
"mconsole=notify:<socket>\n"
" Requests that the mconsole driver send a message to the named Unix\n"
" socket containing the name of the mconsole socket. This also serves\n"
" to notify outside processes when UML has booted far enough to respond\n"
" to mconsole requests.\n\n"
);
static int notify_panic(struct notifier_block *self, unsigned long unused1,
void *ptr)
{
char *message = ptr;
if(notify_socket == NULL) return(0);
mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
strlen(message) + 1);
return(0);
}
static struct notifier_block panic_exit_notifier = {
.notifier_call = notify_panic,
.next = NULL,
.priority = 1
};
static int add_notifier(void)
{
notifier_chain_register(&panic_notifier_list, &panic_exit_notifier);
return(0);
}
__initcall(add_notifier);
char *mconsole_notify_socket(void)
{
return(notify_socket);
}
EXPORT_SYMBOL(mconsole_notify_socket);
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
* adjust the settings for this buffer only. This must remain at the end
* of the file.
* ---------------------------------------------------------------------------
* Local variables:
* c-file-style: "linux"
* End:
*/