Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / arch / um / drivers / mconsole_kern.c
blobd5f9a2d1da1ba8f8e667e3fc781db1a5136432af
1 /*
2 * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org)
3 * Copyright (C) 2001 - 2008 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4 * Licensed under the GPL
5 */
7 #include <linux/console.h>
8 #include <linux/ctype.h>
9 #include <linux/string.h>
10 #include <linux/interrupt.h>
11 #include <linux/list.h>
12 #include <linux/mm.h>
13 #include <linux/module.h>
14 #include <linux/notifier.h>
15 #include <linux/reboot.h>
16 #include <linux/sched/debug.h>
17 #include <linux/proc_fs.h>
18 #include <linux/slab.h>
19 #include <linux/syscalls.h>
20 #include <linux/utsname.h>
21 #include <linux/socket.h>
22 #include <linux/un.h>
23 #include <linux/workqueue.h>
24 #include <linux/mutex.h>
25 #include <linux/fs.h>
26 #include <linux/mount.h>
27 #include <linux/file.h>
28 #include <linux/uaccess.h>
29 #include <asm/switch_to.h>
31 #include <init.h>
32 #include <irq_kern.h>
33 #include <irq_user.h>
34 #include <kern_util.h>
35 #include "mconsole.h"
36 #include "mconsole_kern.h"
37 #include <os.h>
39 static int do_unlink_socket(struct notifier_block *notifier,
40 unsigned long what, void *data)
42 return mconsole_unlink_socket();
46 static struct notifier_block reboot_notifier = {
47 .notifier_call = do_unlink_socket,
48 .priority = 0,
51 /* Safe without explicit locking for now. Tasklets provide their own
52 * locking, and the interrupt handler is safe because it can't interrupt
53 * itself and it can only happen on CPU 0.
56 static LIST_HEAD(mc_requests);
58 static void mc_work_proc(struct work_struct *unused)
60 struct mconsole_entry *req;
61 unsigned long flags;
63 while (!list_empty(&mc_requests)) {
64 local_irq_save(flags);
65 req = list_entry(mc_requests.next, struct mconsole_entry, list);
66 list_del(&req->list);
67 local_irq_restore(flags);
68 req->request.cmd->handler(&req->request);
69 kfree(req);
73 static DECLARE_WORK(mconsole_work, mc_work_proc);
75 static irqreturn_t mconsole_interrupt(int irq, void *dev_id)
77 /* long to avoid size mismatch warnings from gcc */
78 long fd;
79 struct mconsole_entry *new;
80 static struct mc_request req; /* that's OK */
82 fd = (long) dev_id;
83 while (mconsole_get_request(fd, &req)) {
84 if (req.cmd->context == MCONSOLE_INTR)
85 (*req.cmd->handler)(&req);
86 else {
87 new = kmalloc(sizeof(*new), GFP_NOWAIT);
88 if (new == NULL)
89 mconsole_reply(&req, "Out of memory", 1, 0);
90 else {
91 new->request = req;
92 new->request.regs = get_irq_regs()->regs;
93 list_add(&new->list, &mc_requests);
97 if (!list_empty(&mc_requests))
98 schedule_work(&mconsole_work);
99 reactivate_fd(fd, MCONSOLE_IRQ);
100 return IRQ_HANDLED;
103 void mconsole_version(struct mc_request *req)
105 char version[256];
107 sprintf(version, "%s %s %s %s %s", utsname()->sysname,
108 utsname()->nodename, utsname()->release, utsname()->version,
109 utsname()->machine);
110 mconsole_reply(req, version, 0, 0);
113 void mconsole_log(struct mc_request *req)
115 int len;
116 char *ptr = req->request.data;
118 ptr += strlen("log ");
120 len = req->len - (ptr - req->request.data);
121 printk(KERN_WARNING "%.*s", len, ptr);
122 mconsole_reply(req, "", 0, 0);
125 void mconsole_proc(struct mc_request *req)
127 struct vfsmount *mnt = task_active_pid_ns(current)->proc_mnt;
128 char *buf;
129 int len;
130 struct file *file;
131 int first_chunk = 1;
132 char *ptr = req->request.data;
133 loff_t pos = 0;
135 ptr += strlen("proc");
136 ptr = skip_spaces(ptr);
138 file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0);
139 if (IS_ERR(file)) {
140 mconsole_reply(req, "Failed to open file", 1, 0);
141 printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
142 goto out;
145 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
146 if (buf == NULL) {
147 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
148 goto out_fput;
151 do {
152 len = kernel_read(file, buf, PAGE_SIZE - 1, &pos);
153 if (len < 0) {
154 mconsole_reply(req, "Read of file failed", 1, 0);
155 goto out_free;
157 /* Begin the file content on his own line. */
158 if (first_chunk) {
159 mconsole_reply(req, "\n", 0, 1);
160 first_chunk = 0;
162 buf[len] = '\0';
163 mconsole_reply(req, buf, 0, (len > 0));
164 } while (len > 0);
165 out_free:
166 kfree(buf);
167 out_fput:
168 fput(file);
169 out: ;
172 #define UML_MCONSOLE_HELPTEXT \
173 "Commands: \n\
174 version - Get kernel version \n\
175 help - Print this message \n\
176 halt - Halt UML \n\
177 reboot - Reboot UML \n\
178 config <dev>=<config> - Add a new device to UML; \n\
179 same syntax as command line \n\
180 config <dev> - Query the configuration of a device \n\
181 remove <dev> - Remove a device from UML \n\
182 sysrq <letter> - Performs the SysRq action controlled by the letter \n\
183 cad - invoke the Ctrl-Alt-Del handler \n\
184 stop - pause the UML; it will do nothing until it receives a 'go' \n\
185 go - continue the UML after a 'stop' \n\
186 log <string> - make UML enter <string> into the kernel log\n\
187 proc <file> - returns the contents of the UML's /proc/<file>\n\
188 stack <pid> - returns the stack of the specified pid\n\
191 void mconsole_help(struct mc_request *req)
193 mconsole_reply(req, UML_MCONSOLE_HELPTEXT, 0, 0);
196 void mconsole_halt(struct mc_request *req)
198 mconsole_reply(req, "", 0, 0);
199 machine_halt();
202 void mconsole_reboot(struct mc_request *req)
204 mconsole_reply(req, "", 0, 0);
205 machine_restart(NULL);
208 void mconsole_cad(struct mc_request *req)
210 mconsole_reply(req, "", 0, 0);
211 ctrl_alt_del();
214 void mconsole_go(struct mc_request *req)
216 mconsole_reply(req, "Not stopped", 1, 0);
219 void mconsole_stop(struct mc_request *req)
221 deactivate_fd(req->originating_fd, MCONSOLE_IRQ);
222 os_set_fd_block(req->originating_fd, 1);
223 mconsole_reply(req, "stopped", 0, 0);
224 for (;;) {
225 if (!mconsole_get_request(req->originating_fd, req))
226 continue;
227 if (req->cmd->handler == mconsole_go)
228 break;
229 if (req->cmd->handler == mconsole_stop) {
230 mconsole_reply(req, "Already stopped", 1, 0);
231 continue;
233 if (req->cmd->handler == mconsole_sysrq) {
234 struct pt_regs *old_regs;
235 old_regs = set_irq_regs((struct pt_regs *)&req->regs);
236 mconsole_sysrq(req);
237 set_irq_regs(old_regs);
238 continue;
240 (*req->cmd->handler)(req);
242 os_set_fd_block(req->originating_fd, 0);
243 reactivate_fd(req->originating_fd, MCONSOLE_IRQ);
244 mconsole_reply(req, "", 0, 0);
247 static DEFINE_SPINLOCK(mc_devices_lock);
248 static LIST_HEAD(mconsole_devices);
250 void mconsole_register_dev(struct mc_device *new)
252 spin_lock(&mc_devices_lock);
253 BUG_ON(!list_empty(&new->list));
254 list_add(&new->list, &mconsole_devices);
255 spin_unlock(&mc_devices_lock);
258 static struct mc_device *mconsole_find_dev(char *name)
260 struct list_head *ele;
261 struct mc_device *dev;
263 list_for_each(ele, &mconsole_devices) {
264 dev = list_entry(ele, struct mc_device, list);
265 if (!strncmp(name, dev->name, strlen(dev->name)))
266 return dev;
268 return NULL;
271 #define UNPLUGGED_PER_PAGE \
272 ((PAGE_SIZE - sizeof(struct list_head)) / sizeof(unsigned long))
274 struct unplugged_pages {
275 struct list_head list;
276 void *pages[UNPLUGGED_PER_PAGE];
279 static DEFINE_MUTEX(plug_mem_mutex);
280 static unsigned long long unplugged_pages_count = 0;
281 static LIST_HEAD(unplugged_pages);
282 static int unplug_index = UNPLUGGED_PER_PAGE;
284 static int mem_config(char *str, char **error_out)
286 unsigned long long diff;
287 int err = -EINVAL, i, add;
288 char *ret;
290 if (str[0] != '=') {
291 *error_out = "Expected '=' after 'mem'";
292 goto out;
295 str++;
296 if (str[0] == '-')
297 add = 0;
298 else if (str[0] == '+') {
299 add = 1;
301 else {
302 *error_out = "Expected increment to start with '-' or '+'";
303 goto out;
306 str++;
307 diff = memparse(str, &ret);
308 if (*ret != '\0') {
309 *error_out = "Failed to parse memory increment";
310 goto out;
313 diff /= PAGE_SIZE;
315 mutex_lock(&plug_mem_mutex);
316 for (i = 0; i < diff; i++) {
317 struct unplugged_pages *unplugged;
318 void *addr;
320 if (add) {
321 if (list_empty(&unplugged_pages))
322 break;
324 unplugged = list_entry(unplugged_pages.next,
325 struct unplugged_pages, list);
326 if (unplug_index > 0)
327 addr = unplugged->pages[--unplug_index];
328 else {
329 list_del(&unplugged->list);
330 addr = unplugged;
331 unplug_index = UNPLUGGED_PER_PAGE;
334 free_page((unsigned long) addr);
335 unplugged_pages_count--;
337 else {
338 struct page *page;
340 page = alloc_page(GFP_ATOMIC);
341 if (page == NULL)
342 break;
344 unplugged = page_address(page);
345 if (unplug_index == UNPLUGGED_PER_PAGE) {
346 list_add(&unplugged->list, &unplugged_pages);
347 unplug_index = 0;
349 else {
350 struct list_head *entry = unplugged_pages.next;
351 addr = unplugged;
353 unplugged = list_entry(entry,
354 struct unplugged_pages,
355 list);
356 err = os_drop_memory(addr, PAGE_SIZE);
357 if (err) {
358 printk(KERN_ERR "Failed to release "
359 "memory - errno = %d\n", err);
360 *error_out = "Failed to release memory";
361 goto out_unlock;
363 unplugged->pages[unplug_index++] = addr;
366 unplugged_pages_count++;
370 err = 0;
371 out_unlock:
372 mutex_unlock(&plug_mem_mutex);
373 out:
374 return err;
377 static int mem_get_config(char *name, char *str, int size, char **error_out)
379 char buf[sizeof("18446744073709551615")];
380 int len = 0;
382 sprintf(buf, "%ld", uml_physmem);
383 CONFIG_CHUNK(str, size, len, buf, 1);
385 return len;
388 static int mem_id(char **str, int *start_out, int *end_out)
390 *start_out = 0;
391 *end_out = 0;
393 return 0;
396 static int mem_remove(int n, char **error_out)
398 *error_out = "Memory doesn't support the remove operation";
399 return -EBUSY;
402 static struct mc_device mem_mc = {
403 .list = LIST_HEAD_INIT(mem_mc.list),
404 .name = "mem",
405 .config = mem_config,
406 .get_config = mem_get_config,
407 .id = mem_id,
408 .remove = mem_remove,
411 static int __init mem_mc_init(void)
413 if (can_drop_memory())
414 mconsole_register_dev(&mem_mc);
415 else printk(KERN_ERR "Can't release memory to the host - memory "
416 "hotplug won't be supported\n");
417 return 0;
420 __initcall(mem_mc_init);
422 #define CONFIG_BUF_SIZE 64
424 static void mconsole_get_config(int (*get_config)(char *, char *, int,
425 char **),
426 struct mc_request *req, char *name)
428 char default_buf[CONFIG_BUF_SIZE], *error, *buf;
429 int n, size;
431 if (get_config == NULL) {
432 mconsole_reply(req, "No get_config routine defined", 1, 0);
433 return;
436 error = NULL;
437 size = ARRAY_SIZE(default_buf);
438 buf = default_buf;
440 while (1) {
441 n = (*get_config)(name, buf, size, &error);
442 if (error != NULL) {
443 mconsole_reply(req, error, 1, 0);
444 goto out;
447 if (n <= size) {
448 mconsole_reply(req, buf, 0, 0);
449 goto out;
452 if (buf != default_buf)
453 kfree(buf);
455 size = n;
456 buf = kmalloc(size, GFP_KERNEL);
457 if (buf == NULL) {
458 mconsole_reply(req, "Failed to allocate buffer", 1, 0);
459 return;
462 out:
463 if (buf != default_buf)
464 kfree(buf);
467 void mconsole_config(struct mc_request *req)
469 struct mc_device *dev;
470 char *ptr = req->request.data, *name, *error_string = "";
471 int err;
473 ptr += strlen("config");
474 ptr = skip_spaces(ptr);
475 dev = mconsole_find_dev(ptr);
476 if (dev == NULL) {
477 mconsole_reply(req, "Bad configuration option", 1, 0);
478 return;
481 name = &ptr[strlen(dev->name)];
482 ptr = name;
483 while ((*ptr != '=') && (*ptr != '\0'))
484 ptr++;
486 if (*ptr == '=') {
487 err = (*dev->config)(name, &error_string);
488 mconsole_reply(req, error_string, err, 0);
490 else mconsole_get_config(dev->get_config, req, name);
493 void mconsole_remove(struct mc_request *req)
495 struct mc_device *dev;
496 char *ptr = req->request.data, *err_msg = "";
497 char error[256];
498 int err, start, end, n;
500 ptr += strlen("remove");
501 ptr = skip_spaces(ptr);
502 dev = mconsole_find_dev(ptr);
503 if (dev == NULL) {
504 mconsole_reply(req, "Bad remove option", 1, 0);
505 return;
508 ptr = &ptr[strlen(dev->name)];
510 err = 1;
511 n = (*dev->id)(&ptr, &start, &end);
512 if (n < 0) {
513 err_msg = "Couldn't parse device number";
514 goto out;
516 else if ((n < start) || (n > end)) {
517 sprintf(error, "Invalid device number - must be between "
518 "%d and %d", start, end);
519 err_msg = error;
520 goto out;
523 err_msg = NULL;
524 err = (*dev->remove)(n, &err_msg);
525 switch(err) {
526 case 0:
527 err_msg = "";
528 break;
529 case -ENODEV:
530 if (err_msg == NULL)
531 err_msg = "Device doesn't exist";
532 break;
533 case -EBUSY:
534 if (err_msg == NULL)
535 err_msg = "Device is currently open";
536 break;
537 default:
538 break;
540 out:
541 mconsole_reply(req, err_msg, err, 0);
544 struct mconsole_output {
545 struct list_head list;
546 struct mc_request *req;
549 static DEFINE_SPINLOCK(client_lock);
550 static LIST_HEAD(clients);
551 static char console_buf[MCONSOLE_MAX_DATA];
553 static void console_write(struct console *console, const char *string,
554 unsigned int len)
556 struct list_head *ele;
557 int n;
559 if (list_empty(&clients))
560 return;
562 while (len > 0) {
563 n = min((size_t) len, ARRAY_SIZE(console_buf));
564 strncpy(console_buf, string, n);
565 string += n;
566 len -= n;
568 list_for_each(ele, &clients) {
569 struct mconsole_output *entry;
571 entry = list_entry(ele, struct mconsole_output, list);
572 mconsole_reply_len(entry->req, console_buf, n, 0, 1);
577 static struct console mc_console = { .name = "mc",
578 .write = console_write,
579 .flags = CON_ENABLED,
580 .index = -1 };
582 static int mc_add_console(void)
584 register_console(&mc_console);
585 return 0;
588 late_initcall(mc_add_console);
590 static void with_console(struct mc_request *req, void (*proc)(void *),
591 void *arg)
593 struct mconsole_output entry;
594 unsigned long flags;
596 entry.req = req;
597 spin_lock_irqsave(&client_lock, flags);
598 list_add(&entry.list, &clients);
599 spin_unlock_irqrestore(&client_lock, flags);
601 (*proc)(arg);
603 mconsole_reply_len(req, "", 0, 0, 0);
605 spin_lock_irqsave(&client_lock, flags);
606 list_del(&entry.list);
607 spin_unlock_irqrestore(&client_lock, flags);
610 #ifdef CONFIG_MAGIC_SYSRQ
612 #include <linux/sysrq.h>
614 static void sysrq_proc(void *arg)
616 char *op = arg;
617 handle_sysrq(*op);
620 void mconsole_sysrq(struct mc_request *req)
622 char *ptr = req->request.data;
624 ptr += strlen("sysrq");
625 ptr = skip_spaces(ptr);
628 * With 'b', the system will shut down without a chance to reply,
629 * so in this case, we reply first.
631 if (*ptr == 'b')
632 mconsole_reply(req, "", 0, 0);
634 with_console(req, sysrq_proc, ptr);
636 #else
637 void mconsole_sysrq(struct mc_request *req)
639 mconsole_reply(req, "Sysrq not compiled in", 1, 0);
641 #endif
643 static void stack_proc(void *arg)
645 struct task_struct *task = arg;
647 show_stack(task, NULL);
651 * Mconsole stack trace
652 * Added by Allan Graves, Jeff Dike
653 * Dumps a stacks registers to the linux console.
654 * Usage stack <pid>.
656 void mconsole_stack(struct mc_request *req)
658 char *ptr = req->request.data;
659 int pid_requested= -1;
660 struct task_struct *to = NULL;
663 * Would be nice:
664 * 1) Send showregs output to mconsole.
665 * 2) Add a way to stack dump all pids.
668 ptr += strlen("stack");
669 ptr = skip_spaces(ptr);
672 * Should really check for multiple pids or reject bad args here
674 /* What do the arguments in mconsole_reply mean? */
675 if (sscanf(ptr, "%d", &pid_requested) == 0) {
676 mconsole_reply(req, "Please specify a pid", 1, 0);
677 return;
680 to = find_task_by_pid_ns(pid_requested, &init_pid_ns);
681 if ((to == NULL) || (pid_requested == 0)) {
682 mconsole_reply(req, "Couldn't find that pid", 1, 0);
683 return;
685 with_console(req, stack_proc, to);
689 * Changed by mconsole_setup, which is __setup, and called before SMP is
690 * active.
692 static char *notify_socket = NULL;
694 static int __init mconsole_init(void)
696 /* long to avoid size mismatch warnings from gcc */
697 long sock;
698 int err;
699 char file[UNIX_PATH_MAX];
701 if (umid_file_name("mconsole", file, sizeof(file)))
702 return -1;
703 snprintf(mconsole_socket_name, sizeof(file), "%s", file);
705 sock = os_create_unix_socket(file, sizeof(file), 1);
706 if (sock < 0) {
707 printk(KERN_ERR "Failed to initialize management console\n");
708 return 1;
710 if (os_set_fd_block(sock, 0))
711 goto out;
713 register_reboot_notifier(&reboot_notifier);
715 err = um_request_irq(MCONSOLE_IRQ, sock, IRQ_READ, mconsole_interrupt,
716 IRQF_SHARED, "mconsole", (void *)sock);
717 if (err) {
718 printk(KERN_ERR "Failed to get IRQ for management console\n");
719 goto out;
722 if (notify_socket != NULL) {
723 notify_socket = kstrdup(notify_socket, GFP_KERNEL);
724 if (notify_socket != NULL)
725 mconsole_notify(notify_socket, MCONSOLE_SOCKET,
726 mconsole_socket_name,
727 strlen(mconsole_socket_name) + 1);
728 else printk(KERN_ERR "mconsole_setup failed to strdup "
729 "string\n");
732 printk(KERN_INFO "mconsole (version %d) initialized on %s\n",
733 MCONSOLE_VERSION, mconsole_socket_name);
734 return 0;
736 out:
737 os_close_file(sock);
738 return 1;
741 __initcall(mconsole_init);
743 static ssize_t mconsole_proc_write(struct file *file,
744 const char __user *buffer, size_t count, loff_t *pos)
746 char *buf;
748 buf = memdup_user_nul(buffer, count);
749 if (IS_ERR(buf))
750 return PTR_ERR(buf);
752 mconsole_notify(notify_socket, MCONSOLE_USER_NOTIFY, buf, count);
753 kfree(buf);
754 return count;
757 static const struct file_operations mconsole_proc_fops = {
758 .owner = THIS_MODULE,
759 .write = mconsole_proc_write,
760 .llseek = noop_llseek,
763 static int create_proc_mconsole(void)
765 struct proc_dir_entry *ent;
767 if (notify_socket == NULL)
768 return 0;
770 ent = proc_create("mconsole", 0200, NULL, &mconsole_proc_fops);
771 if (ent == NULL) {
772 printk(KERN_INFO "create_proc_mconsole : proc_create failed\n");
773 return 0;
775 return 0;
778 static DEFINE_SPINLOCK(notify_spinlock);
780 void lock_notify(void)
782 spin_lock(&notify_spinlock);
785 void unlock_notify(void)
787 spin_unlock(&notify_spinlock);
790 __initcall(create_proc_mconsole);
792 #define NOTIFY "notify:"
794 static int mconsole_setup(char *str)
796 if (!strncmp(str, NOTIFY, strlen(NOTIFY))) {
797 str += strlen(NOTIFY);
798 notify_socket = str;
800 else printk(KERN_ERR "mconsole_setup : Unknown option - '%s'\n", str);
801 return 1;
804 __setup("mconsole=", mconsole_setup);
806 __uml_help(mconsole_setup,
807 "mconsole=notify:<socket>\n"
808 " Requests that the mconsole driver send a message to the named Unix\n"
809 " socket containing the name of the mconsole socket. This also serves\n"
810 " to notify outside processes when UML has booted far enough to respond\n"
811 " to mconsole requests.\n\n"
814 static int notify_panic(struct notifier_block *self, unsigned long unused1,
815 void *ptr)
817 char *message = ptr;
819 if (notify_socket == NULL)
820 return 0;
822 mconsole_notify(notify_socket, MCONSOLE_PANIC, message,
823 strlen(message) + 1);
824 return 0;
827 static struct notifier_block panic_exit_notifier = {
828 .notifier_call = notify_panic,
829 .next = NULL,
830 .priority = 1
833 static int add_notifier(void)
835 atomic_notifier_chain_register(&panic_notifier_list,
836 &panic_exit_notifier);
837 return 0;
840 __initcall(add_notifier);
842 char *mconsole_notify_socket(void)
844 return notify_socket;
847 EXPORT_SYMBOL(mconsole_notify_socket);