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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /arch/um/drivers/mconsole_kern.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'arch/um/drivers/mconsole_kern.c')
-rw-r--r--arch/um/drivers/mconsole_kern.c871
1 files changed, 871 insertions, 0 deletions
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
new file mode 100644
index 000000000..5026e7b9a
--- /dev/null
+++ b/arch/um/drivers/mconsole_kern.c
@@ -0,0 +1,871 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
+ * Copyright (C) 2001 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ */
+
+#include <linux/console.h>
+#include <linux/ctype.h>
+#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/panic_notifier.h>
+#include <linux/reboot.h>
+#include <linux/sched/debug.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 <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/file.h>
+#include <linux/uaccess.h>
+#include <asm/switch_to.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 struct vfsmount *proc_mnt = NULL;
+
+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);
+ 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);
+}
+
+void mconsole_proc(struct mc_request *req)
+{
+ struct vfsmount *mnt = proc_mnt;
+ char *buf;
+ int len;
+ struct file *file;
+ int first_chunk = 1;
+ char *ptr = req->request.data;
+ loff_t pos = 0;
+
+ ptr += strlen("proc");
+ ptr = skip_spaces(ptr);
+
+ if (!mnt) {
+ mconsole_reply(req, "Proc not available", 1, 0);
+ goto out;
+ }
+ file = file_open_root_mnt(mnt, ptr, O_RDONLY, 0);
+ if (IS_ERR(file)) {
+ mconsole_reply(req, "Failed to open file", 1, 0);
+ printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
+ goto out;
+ }
+
+ buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (buf == NULL) {
+ mconsole_reply(req, "Failed to allocate buffer", 1, 0);
+ goto out_fput;
+ }
+
+ do {
+ len = kernel_read(file, buf, PAGE_SIZE - 1, &pos);
+ 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;
+ }
+ buf[len] = '\0';
+ mconsole_reply(req, buf, 0, (len > 0));
+ } while (len > 0);
+ out_free:
+ kfree(buf);
+ out_fput:
+ fput(file);
+ out: ;
+}
+
+#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)
+{
+ block_signals();
+ 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);
+ mconsole_reply(req, "", 0, 0);
+ unblock_signals();
+}
+
+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;
+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");
+ 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");
+ 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");
+ 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 *task = arg;
+
+ show_stack(task, NULL, KERN_INFO);
+}
+
+/*
+ * Mconsole stack trace
+ * Added by Allan Graves, Jeff Dike
+ * Dumps a stacks registers to the linux console.
+ * Usage stack <pid>.
+ */
+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");
+ 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);
+}
+
+static int __init mount_proc(void)
+{
+ struct file_system_type *proc_fs_type;
+ struct vfsmount *mnt;
+
+ proc_fs_type = get_fs_type("proc");
+ if (!proc_fs_type)
+ return -ENODEV;
+
+ mnt = kern_mount(proc_fs_type);
+ put_filesystem(proc_fs_type);
+ if (IS_ERR(mnt))
+ return PTR_ERR(mnt);
+
+ proc_mnt = mnt;
+ return 0;
+}
+
+/*
+ * 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];
+
+ mount_proc();
+
+ 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_SHARED, "mconsole", (void *)sock);
+ if (err < 0) {
+ 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 = memdup_user_nul(buffer, count);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
+ kfree(buf);
+ return count;
+}
+
+static const struct proc_ops mconsole_proc_ops = {
+ .proc_write = mconsole_proc_write,
+ .proc_lseek = 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_ops);
+ if (ent == NULL) {
+ printk(KERN_INFO "create_proc_mconsole : proc_create 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 NOTIFY_DONE;
+}
+
+static struct notifier_block panic_exit_notifier = {
+ .notifier_call = notify_panic,
+ .priority = INT_MAX, /* run as soon as possible */
+};
+
+static int add_notifier(void)
+{
+ 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);