linux/arch/um/drivers/mconsole_kern.c

918 lines
20 KiB
C
Raw Normal View History

/*
* Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
* Copyright (C) 2001 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <linux/console.h>
#include <linux/ctype.h>
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/notifier.h>
#include <linux/reboot.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/syscalls.h>
#include <linux/utsname.h>
#include <linux/socket.h>
#include <linux/un.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <asm/uaccess.h>
#include "init.h"
#include "irq_kern.h"
#include "irq_user.h"
#include "kern_util.h"
#include "mconsole.h"
#include "mconsole_kern.h"
#include "os.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.
*/
static LIST_HEAD(mc_requests);
static void mc_work_proc(struct work_struct *unused)
{
struct mconsole_entry *req;
unsigned long flags;
while (!list_empty(&mc_requests)) {
local_irq_save(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);
}
}
static DECLARE_WORK(mconsole_work, mc_work_proc);
static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
{
/* long to avoid size mismatch warnings from gcc */
long fd;
struct mconsole_entry *new;
static struct mc_request req; /* that's OK */
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_NOWAIT);
if (new == NULL)
mconsole_reply(&req, "Out of memory", 1, 0);
else {
new->request = req;
new->request.regs = get_irq_regs()->regs;
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", utsname()->sysname,
utsname()->nodename, utsname()->release, utsname()->version,
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(KERN_WARNING "%.*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 vfsmount *mnt = current->nsproxy->pid_ns->proc_mnt;
struct file *file;
int n;
char *ptr = req->request.data, *buf;
mm_segment_t old_fs = get_fs();
ptr += strlen("proc");
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
ptr = skip_spaces(ptr);
file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY);
if (IS_ERR(file)) {
mconsole_reply(req, "Failed to open file", 1, 0);
goto out;
}
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->read) {
do {
loff_t pos;
set_fs(KERNEL_DS);
n = vfs_read(file, buf, PAGE_SIZE - 1, &pos);
file_pos_write(file, pos);
set_fs(old_fs);
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: ;
}
#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");
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
ptr = skip_spaces(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(KERN_ERR "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 Ctrl-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);
}
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, "stopped", 0, 0);
for (;;) {
if (!mconsole_get_request(req->originating_fd, req))
continue;
if (req->cmd->handler == mconsole_go)
break;
if (req->cmd->handler == mconsole_stop) {
mconsole_reply(req, "Already stopped", 1, 0);
continue;
}
if (req->cmd->handler == mconsole_sysrq) {
struct pt_regs *old_regs;
old_regs = set_irq_regs((struct pt_regs *)&req->regs);
mconsole_sysrq(req);
set_irq_regs(old_regs);
continue;
}
(*req->cmd->handler)(req);
}
os_set_fd_block(req->originating_fd, 0);
reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
mconsole_reply(req, "", 0, 0);
}
static DEFINE_SPINLOCK(mc_devices_lock);
static LIST_HEAD(mconsole_devices);
void mconsole_register_dev(struct mc_device *new)
{
spin_lock(&mc_devices_lock);
BUG_ON(!list_empty(&new->list));
list_add(&new->list, &mconsole_devices);
spin_unlock(&mc_devices_lock);
}
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 UNPLUGGED_PER_PAGE \
((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
struct unplugged_pages {
struct list_head list;
void *pages[UNPLUGGED_PER_PAGE];
};
static DEFINE_MUTEX(plug_mem_mutex);
static unsigned long long unplugged_pages_count = 0;
static LIST_HEAD(unplugged_pages);
static int unplug_index = UNPLUGGED_PER_PAGE;
static int mem_config(char *str, char **error_out)
{
unsigned long long diff;
int err = -EINVAL, i, add;
char *ret;
if (str[0] != '=') {
*error_out = "Expected '=' after 'mem'";
goto out;
}
str++;
if (str[0] == '-')
add = 0;
else if (str[0] == '+') {
add = 1;
}
else {
*error_out = "Expected increment to start with '-' or '+'";
goto out;
}
str++;
diff = memparse(str, &ret);
if (*ret != '\0') {
*error_out = "Failed to parse memory increment";
goto out;
}
diff /= PAGE_SIZE;
mutex_lock(&plug_mem_mutex);
for (i = 0; i < diff; i++) {
struct unplugged_pages *unplugged;
void *addr;
if (add) {
if (list_empty(&unplugged_pages))
break;
unplugged = list_entry(unplugged_pages.next,
struct unplugged_pages, list);
if (unplug_index > 0)
addr = unplugged->pages[--unplug_index];
else {
list_del(&unplugged->list);
addr = unplugged;
unplug_index = UNPLUGGED_PER_PAGE;
}
free_page((unsigned long) addr);
unplugged_pages_count--;
}
else {
struct page *page;
page = alloc_page(GFP_ATOMIC);
if (page == NULL)
break;
unplugged = page_address(page);
if (unplug_index == UNPLUGGED_PER_PAGE) {
list_add(&unplugged->list, &unplugged_pages);
unplug_index = 0;
}
else {
struct list_head *entry = unplugged_pages.next;
addr = unplugged;
unplugged = list_entry(entry,
struct unplugged_pages,
list);
err = os_drop_memory(addr, PAGE_SIZE);
if (err) {
printk(KERN_ERR "Failed to release "
"memory - errno = %d\n", err);
*error_out = "Failed to release memory";
goto out_unlock;
}
unplugged->pages[unplug_index++] = addr;
}
unplugged_pages_count++;
}
}
err = 0;
out_unlock:
mutex_unlock(&plug_mem_mutex);
out:
return err;
}
static int mem_get_config(char *name, char *str, int size, char **error_out)
{
char buf[sizeof("18446744073709551615")];
int len = 0;
sprintf(buf, "%ld", uml_physmem);
CONFIG_CHUNK(str, size, len, buf, 1);
return len;
}
static int mem_id(char **str, int *start_out, int *end_out)
{
*start_out = 0;
*end_out = 0;
return 0;
}
static int mem_remove(int n, char **error_out)
{
*error_out = "Memory doesn't support the remove operation";
return -EBUSY;
}
static struct mc_device mem_mc = {
.list = LIST_HEAD_INIT(mem_mc.list),
.name = "mem",
.config = mem_config,
.get_config = mem_get_config,
.id = mem_id,
.remove = mem_remove,
};
static int __init mem_mc_init(void)
{
if (can_drop_memory())
mconsole_register_dev(&mem_mc);
else printk(KERN_ERR "Can't release memory to the host - memory "
"hotplug won't be supported\n");
return 0;
}
__initcall(mem_mc_init);
#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 = ARRAY_SIZE(default_buf);
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, *error_string = "";
int err;
ptr += strlen("config");
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
ptr = skip_spaces(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, &error_string);
mconsole_reply(req, error_string, 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");
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
ptr = skip_spaces(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_msg = NULL;
err = (*dev->remove)(n, &err_msg);
switch(err) {
case 0:
err_msg = "";
break;
case -ENODEV:
if (err_msg == NULL)
err_msg = "Device doesn't exist";
break;
case -EBUSY:
if (err_msg == NULL)
err_msg = "Device is currently open";
break;
default:
break;
}
out:
mconsole_reply(req, err_msg, err, 0);
}
struct mconsole_output {
struct list_head list;
struct mc_request *req;
};
static DEFINE_SPINLOCK(client_lock);
static LIST_HEAD(clients);
static char console_buf[MCONSOLE_MAX_DATA];
static void console_write(struct console *console, const char *string,
unsigned int len)
{
struct list_head *ele;
int n;
if (list_empty(&clients))
return;
while (len > 0) {
n = min((size_t) len, ARRAY_SIZE(console_buf));
strncpy(console_buf, string, n);
string += n;
len -= n;
list_for_each(ele, &clients) {
struct mconsole_output *entry;
entry = list_entry(ele, struct mconsole_output, list);
mconsole_reply_len(entry->req, console_buf, n, 0, 1);
}
}
}
static struct console mc_console = { .name = "mc",
.write = console_write,
.flags = CON_ENABLED,
.index = -1 };
static int mc_add_console(void)
{
register_console(&mc_console);
return 0;
}
late_initcall(mc_add_console);
static void with_console(struct mc_request *req, void (*proc)(void *),
void *arg)
{
struct mconsole_output entry;
unsigned long flags;
entry.req = req;
spin_lock_irqsave(&client_lock, flags);
list_add(&entry.list, &clients);
spin_unlock_irqrestore(&client_lock, flags);
(*proc)(arg);
mconsole_reply_len(req, "", 0, 0, 0);
spin_lock_irqsave(&client_lock, flags);
list_del(&entry.list);
spin_unlock_irqrestore(&client_lock, flags);
}
#ifdef CONFIG_MAGIC_SYSRQ
#include <linux/sysrq.h>
static void sysrq_proc(void *arg)
{
char *op = arg;
handle_sysrq(*op);
}
void mconsole_sysrq(struct mc_request *req)
{
char *ptr = req->request.data;
ptr += strlen("sysrq");
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
ptr = skip_spaces(ptr);
/*
* With 'b', the system will shut down without a chance to reply,
* so in this case, we reply first.
*/
if (*ptr == 'b')
mconsole_reply(req, "", 0, 0);
with_console(req, sysrq_proc, ptr);
}
#else
void mconsole_sysrq(struct mc_request *req)
{
mconsole_reply(req, "Sysrq not compiled in", 1, 0);
}
#endif
static void stack_proc(void *arg)
{
struct task_struct *from = current, *to = arg;
to->thread.saved_task = from;
switch_to(from, to, from);
}
/*
* Mconsole stack trace
* Added by Allan Graves, Jeff Dike
* Dumps a stacks registers to the linux console.
* Usage stack <pid>.
*/
uml: throw out CONFIG_MODE_TT This patchset throws out tt mode, which has been non-functional for a while. This is done in phases, interspersed with code cleanups on the affected files. The removal is done as follows: remove all code, config options, and files which depend on CONFIG_MODE_TT get rid of the CHOOSE_MODE macro, which decided whether to call tt-mode or skas-mode code, and replace invocations with their skas portions replace all now-trivial procedures with their skas equivalents There are now a bunch of now-redundant pieces of data structures, including mode-specific pieces of the thread structure, pt_regs, and mm_context. These are all replaced with their skas-specific contents. As part of the ongoing style compliance project, I made a style pass over all files that were changed. There are three such patches, one for each phase, covering the files affected by that phase but no later ones. I noticed that we weren't freeing the LDT state associated with a process when it exited, so that's fixed in one of the later patches. The last patch is a tidying patch which I've had for a while, but which caused inexplicable crashes under tt mode. Since that is no longer a problem, this can now go in. This patch: Start getting rid of tt mode support. This patch throws out CONFIG_MODE_TT and all config options, code, and files which depend on it. CONFIG_MODE_SKAS is gone and everything that depends on it is included unconditionally. The few changed lines are in re-written Kconfig help, lines which needed something skas-related removed from them, and a few more which weren't strictly deletions. Signed-off-by: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 08:26:50 +00:00
void mconsole_stack(struct mc_request *req)
{
char *ptr = req->request.data;
int pid_requested= -1;
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");
tree-wide: convert open calls to remove spaces to skip_spaces() lib function Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15 02:01:06 +00:00
ptr = skip_spaces(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;
}
to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
if ((to == NULL) || (pid_requested == 0)) {
mconsole_reply(req, "Couldn't find that pid", 1, 0);
return;
}
with_console(req, stack_proc, to);
}
/*
* Changed by mconsole_setup, which is __setup, and called before SMP is
* active.
*/
static char *notify_socket = NULL;
static int __init mconsole_init(void)
{
/* long to avoid size mismatch warnings from gcc */
long sock;
int err;
char file[UNIX_PATH_MAX];
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(KERN_ERR "Failed to initialize management console\n");
return 1;
}
if (os_set_fd_block(sock, 0))
goto out;
register_reboot_notifier(&reboot_notifier);
err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
IRQF_DISABLED | IRQF_SHARED | IRQF_SAMPLE_RANDOM,
"mconsole", (void *)sock);
if (err) {
printk(KERN_ERR "Failed to get IRQ for management console\n");
goto out;
}
if (notify_socket != NULL) {
notify_socket = kstrdup(notify_socket, GFP_KERNEL);
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(KERN_INFO "mconsole (version %d) initialized on %s\n",
MCONSOLE_VERSION, mconsole_socket_name);
return 0;
out:
os_close_file(sock);
return 1;
}
__initcall(mconsole_init);
static ssize_t mconsole_proc_write(struct file *file,
const char __user *buffer, size_t count, loff_t *pos)
{
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 const struct file_operations mconsole_proc_fops = {
.owner = THIS_MODULE,
.write = mconsole_proc_write,
llseek: automatically add .llseek fop All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-08-15 16:52:59 +00:00
.llseek = noop_llseek,
};
static int create_proc_mconsole(void)
{
struct proc_dir_entry *ent;
if (notify_socket == NULL)
return 0;
ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
if (ent == NULL) {
printk(KERN_INFO "create_proc_mconsole : create_proc_entry "
"failed\n");
return 0;
}
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)
{
[PATCH] Notifier chain update: API changes The kernel's implementation of notifier chains is unsafe. There is no protection against entries being added to or removed from a chain while the chain is in use. The issues were discussed in this thread: http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2 We noticed that notifier chains in the kernel fall into two basic usage classes: "Blocking" chains are always called from a process context and the callout routines are allowed to sleep; "Atomic" chains can be called from an atomic context and the callout routines are not allowed to sleep. We decided to codify this distinction and make it part of the API. Therefore this set of patches introduces three new, parallel APIs: one for blocking notifiers, one for atomic notifiers, and one for "raw" notifiers (which is really just the old API under a new name). New kinds of data structures are used for the heads of the chains, and new routines are defined for registration, unregistration, and calling a chain. The three APIs are explained in include/linux/notifier.h and their implementation is in kernel/sys.c. With atomic and blocking chains, the implementation guarantees that the chain links will not be corrupted and that chain callers will not get messed up by entries being added or removed. For raw chains the implementation provides no guarantees at all; users of this API must provide their own protections. (The idea was that situations may come up where the assumptions of the atomic and blocking APIs are not appropriate, so it should be possible for users to handle these things in their own way.) There are some limitations, which should not be too hard to live with. For atomic/blocking chains, registration and unregistration must always be done in a process context since the chain is protected by a mutex/rwsem. Also, a callout routine for a non-raw chain must not try to register or unregister entries on its own chain. (This did happen in a couple of places and the code had to be changed to avoid it.) Since atomic chains may be called from within an NMI handler, they cannot use spinlocks for synchronization. Instead we use RCU. The overhead falls almost entirely in the unregister routine, which is okay since unregistration is much less frequent that calling a chain. Here is the list of chains that we adjusted and their classifications. None of them use the raw API, so for the moment it is only a placeholder. ATOMIC CHAINS ------------- arch/i386/kernel/traps.c: i386die_chain arch/ia64/kernel/traps.c: ia64die_chain arch/powerpc/kernel/traps.c: powerpc_die_chain arch/sparc64/kernel/traps.c: sparc64die_chain arch/x86_64/kernel/traps.c: die_chain drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list kernel/panic.c: panic_notifier_list kernel/profile.c: task_free_notifier net/bluetooth/hci_core.c: hci_notifier net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain net/ipv6/addrconf.c: inet6addr_chain net/netfilter/nf_conntrack_core.c: nf_conntrack_chain net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain net/netlink/af_netlink.c: netlink_chain BLOCKING CHAINS --------------- arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain arch/s390/kernel/process.c: idle_chain arch/x86_64/kernel/process.c idle_notifier drivers/base/memory.c: memory_chain drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list drivers/macintosh/adb.c: adb_client_list drivers/macintosh/via-pmu.c sleep_notifier_list drivers/macintosh/via-pmu68k.c sleep_notifier_list drivers/macintosh/windfarm_core.c wf_client_list drivers/usb/core/notify.c usb_notifier_list drivers/video/fbmem.c fb_notifier_list kernel/cpu.c cpu_chain kernel/module.c module_notify_list kernel/profile.c munmap_notifier kernel/profile.c task_exit_notifier kernel/sys.c reboot_notifier_list net/core/dev.c netdev_chain net/decnet/dn_dev.c: dnaddr_chain net/ipv4/devinet.c: inetaddr_chain It's possible that some of these classifications are wrong. If they are, please let us know or submit a patch to fix them. Note that any chain that gets called very frequently should be atomic, because the rwsem read-locking used for blocking chains is very likely to incur cache misses on SMP systems. (However, if the chain's callout routines may sleep then the chain cannot be atomic.) The patch set was written by Alan Stern and Chandra Seetharaman, incorporating material written by Keith Owens and suggestions from Paul McKenney and Andrew Morton. [jes@sgi.com: restructure the notifier chain initialization macros] Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: Jes Sorensen <jes@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 09:16:30 +00:00
atomic_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);