blob: 0314e78e31ff1e1951b808964b0b633db35a9591 [file] [log] [blame]
Jason Wesself2d937f2008-04-17 20:05:37 +02001/*
2 * Based on the same principle as kgdboe using the NETPOLL api, this
3 * driver uses a console polling api to implement a gdb serial inteface
4 * which is multiplexed on a console port.
5 *
6 * Maintainer: Jason Wessel <jason.wessel@windriver.com>
7 *
8 * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
9 *
10 * This file is licensed under the terms of the GNU General Public
11 * License version 2. This program is licensed "as is" without any
12 * warranty of any kind, whether express or implied.
13 */
14#include <linux/kernel.h>
15#include <linux/ctype.h>
16#include <linux/kgdb.h>
Jason Wesselada64e42010-05-20 21:04:24 -050017#include <linux/kdb.h>
Jason Wesself2d937f2008-04-17 20:05:37 +020018#include <linux/tty.h>
Jason Wesselefe2f292010-05-20 21:04:26 -050019#include <linux/console.h>
Jason Wessel408a4be2010-08-05 09:22:30 -050020#include <linux/vt_kern.h>
Dmitry Torokhov111c1822010-11-03 11:04:05 -070021#include <linux/input.h>
Paul Gortmaker578b9ce2011-05-27 16:14:23 -040022#include <linux/module.h>
Jason Wesself2d937f2008-04-17 20:05:37 +020023
24#define MAX_CONFIG_LEN 40
25
26static struct kgdb_io kgdboc_io_ops;
27
28/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
29static int configured = -1;
30
31static char config[MAX_CONFIG_LEN];
32static struct kparam_string kps = {
33 .string = config,
34 .maxlen = MAX_CONFIG_LEN,
35};
36
Jason Wessel408a4be2010-08-05 09:22:30 -050037static int kgdboc_use_kms; /* 1 if we use kernel mode switching */
Jason Wesself2d937f2008-04-17 20:05:37 +020038static struct tty_driver *kgdb_tty_driver;
39static int kgdb_tty_line;
40
Jason Wesselada64e42010-05-20 21:04:24 -050041#ifdef CONFIG_KDB_KEYBOARD
Dmitry Torokhov111c1822010-11-03 11:04:05 -070042static int kgdboc_reset_connect(struct input_handler *handler,
43 struct input_dev *dev,
44 const struct input_device_id *id)
45{
46 input_reset_device(dev);
47
Joe Perches9e03aa22013-09-03 13:45:58 -070048 /* Return an error - we do not want to bind, just to reset */
Dmitry Torokhov111c1822010-11-03 11:04:05 -070049 return -ENODEV;
50}
51
52static void kgdboc_reset_disconnect(struct input_handle *handle)
53{
54 /* We do not expect anyone to actually bind to us */
55 BUG();
56}
57
58static const struct input_device_id kgdboc_reset_ids[] = {
59 {
60 .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
61 .evbit = { BIT_MASK(EV_KEY) },
62 },
63 { }
64};
65
66static struct input_handler kgdboc_reset_handler = {
67 .connect = kgdboc_reset_connect,
68 .disconnect = kgdboc_reset_disconnect,
69 .name = "kgdboc_reset",
70 .id_table = kgdboc_reset_ids,
71};
72
73static DEFINE_MUTEX(kgdboc_reset_mutex);
74
75static void kgdboc_restore_input_helper(struct work_struct *dummy)
76{
77 /*
78 * We need to take a mutex to prevent several instances of
79 * this work running on different CPUs so they don't try
80 * to register again already registered handler.
81 */
82 mutex_lock(&kgdboc_reset_mutex);
83
84 if (input_register_handler(&kgdboc_reset_handler) == 0)
85 input_unregister_handler(&kgdboc_reset_handler);
86
87 mutex_unlock(&kgdboc_reset_mutex);
88}
89
90static DECLARE_WORK(kgdboc_restore_input_work, kgdboc_restore_input_helper);
91
92static void kgdboc_restore_input(void)
93{
Jason Wessel8863ada2010-12-01 13:01:01 -060094 if (likely(system_state == SYSTEM_RUNNING))
95 schedule_work(&kgdboc_restore_input_work);
Dmitry Torokhov111c1822010-11-03 11:04:05 -070096}
97
Jason Wesselada64e42010-05-20 21:04:24 -050098static int kgdboc_register_kbd(char **cptr)
99{
Jason Wessel24b85922012-08-10 12:12:23 -0500100 if (strncmp(*cptr, "kbd", 3) == 0 ||
101 strncmp(*cptr, "kdb", 3) == 0) {
Jason Wesselada64e42010-05-20 21:04:24 -0500102 if (kdb_poll_idx < KDB_POLL_FUNC_MAX) {
103 kdb_poll_funcs[kdb_poll_idx] = kdb_get_kbd_char;
104 kdb_poll_idx++;
105 if (cptr[0][3] == ',')
106 *cptr += 4;
107 else
108 return 1;
109 }
110 }
111 return 0;
112}
113
114static void kgdboc_unregister_kbd(void)
115{
116 int i;
117
118 for (i = 0; i < kdb_poll_idx; i++) {
119 if (kdb_poll_funcs[i] == kdb_get_kbd_char) {
120 kdb_poll_idx--;
121 kdb_poll_funcs[i] = kdb_poll_funcs[kdb_poll_idx];
122 kdb_poll_funcs[kdb_poll_idx] = NULL;
123 i--;
124 }
125 }
Tejun Heo43829732012-08-20 14:51:24 -0700126 flush_work(&kgdboc_restore_input_work);
Jason Wesselada64e42010-05-20 21:04:24 -0500127}
128#else /* ! CONFIG_KDB_KEYBOARD */
129#define kgdboc_register_kbd(x) 0
130#define kgdboc_unregister_kbd()
Dmitry Torokhov111c1822010-11-03 11:04:05 -0700131#define kgdboc_restore_input()
Jason Wesselada64e42010-05-20 21:04:24 -0500132#endif /* ! CONFIG_KDB_KEYBOARD */
133
Jason Wesselada64e42010-05-20 21:04:24 -0500134static void cleanup_kgdboc(void)
135{
Anton Vorontsov0c57dfc2012-09-24 14:27:56 -0700136 if (kgdb_unregister_nmi_console())
137 return;
Jason Wesselada64e42010-05-20 21:04:24 -0500138 kgdboc_unregister_kbd();
139 if (configured == 1)
140 kgdb_unregister_io_module(&kgdboc_io_ops);
141}
142
Jason Wesself2d937f2008-04-17 20:05:37 +0200143static int configure_kgdboc(void)
144{
145 struct tty_driver *p;
146 int tty_line = 0;
Laura Abbottd0bf1cb2018-09-10 16:20:14 -0700147 int err = -ENODEV;
Jason Wesselada64e42010-05-20 21:04:24 -0500148 char *cptr = config;
Jason Wesselefe2f292010-05-20 21:04:26 -0500149 struct console *cons;
Jason Wesself2d937f2008-04-17 20:05:37 +0200150
Wentao Wang9b06a0b2019-03-20 15:30:39 +0000151 if (!strlen(config) || isspace(config[0])) {
152 err = 0;
Jason Wesself2d937f2008-04-17 20:05:37 +0200153 goto noconfig;
Wentao Wang9b06a0b2019-03-20 15:30:39 +0000154 }
Jason Wesself2d937f2008-04-17 20:05:37 +0200155
Jason Wesselefe2f292010-05-20 21:04:26 -0500156 kgdboc_io_ops.is_console = 0;
Jason Wesselada64e42010-05-20 21:04:24 -0500157 kgdb_tty_driver = NULL;
Jason Wesself2d937f2008-04-17 20:05:37 +0200158
Jason Wessel408a4be2010-08-05 09:22:30 -0500159 kgdboc_use_kms = 0;
160 if (strncmp(cptr, "kms,", 4) == 0) {
161 cptr += 4;
162 kgdboc_use_kms = 1;
163 }
164
Jason Wesselada64e42010-05-20 21:04:24 -0500165 if (kgdboc_register_kbd(&cptr))
166 goto do_register;
167
168 p = tty_find_polling_driver(cptr, &tty_line);
Jason Wesself2d937f2008-04-17 20:05:37 +0200169 if (!p)
170 goto noconfig;
171
Jason Wesselefe2f292010-05-20 21:04:26 -0500172 cons = console_drivers;
173 while (cons) {
174 int idx;
175 if (cons->device && cons->device(cons, &idx) == p &&
176 idx == tty_line) {
177 kgdboc_io_ops.is_console = 1;
178 break;
179 }
180 cons = cons->next;
181 }
182
Jason Wesself2d937f2008-04-17 20:05:37 +0200183 kgdb_tty_driver = p;
184 kgdb_tty_line = tty_line;
185
Jason Wesselada64e42010-05-20 21:04:24 -0500186do_register:
Jason Wesself2d937f2008-04-17 20:05:37 +0200187 err = kgdb_register_io_module(&kgdboc_io_ops);
188 if (err)
189 goto noconfig;
190
Anton Vorontsov0c57dfc2012-09-24 14:27:56 -0700191 err = kgdb_register_nmi_console();
192 if (err)
193 goto nmi_con_failed;
194
Jason Wesself2d937f2008-04-17 20:05:37 +0200195 configured = 1;
196
197 return 0;
198
Anton Vorontsov0c57dfc2012-09-24 14:27:56 -0700199nmi_con_failed:
200 kgdb_unregister_io_module(&kgdboc_io_ops);
Jason Wesself2d937f2008-04-17 20:05:37 +0200201noconfig:
Anton Vorontsov0c57dfc2012-09-24 14:27:56 -0700202 kgdboc_unregister_kbd();
Jason Wesself2d937f2008-04-17 20:05:37 +0200203 config[0] = 0;
204 configured = 0;
Jason Wesselada64e42010-05-20 21:04:24 -0500205 cleanup_kgdboc();
Jason Wesself2d937f2008-04-17 20:05:37 +0200206
207 return err;
208}
209
210static int __init init_kgdboc(void)
211{
212 /* Already configured? */
213 if (configured == 1)
214 return 0;
215
216 return configure_kgdboc();
217}
218
Jason Wesself2d937f2008-04-17 20:05:37 +0200219static int kgdboc_get_char(void)
220{
Jason Wesselada64e42010-05-20 21:04:24 -0500221 if (!kgdb_tty_driver)
222 return -1;
Alan Coxf34d7a52008-04-30 00:54:13 -0700223 return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
224 kgdb_tty_line);
Jason Wesself2d937f2008-04-17 20:05:37 +0200225}
226
227static void kgdboc_put_char(u8 chr)
228{
Jason Wesselada64e42010-05-20 21:04:24 -0500229 if (!kgdb_tty_driver)
230 return;
Alan Coxf34d7a52008-04-30 00:54:13 -0700231 kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
232 kgdb_tty_line, chr);
Jason Wesself2d937f2008-04-17 20:05:37 +0200233}
234
235static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
236{
Macpaul Lin6d8619272018-10-17 23:08:38 +0800237 size_t len = strlen(kmessage);
Jason Wesselc191e5a2008-02-15 14:55:52 -0600238
239 if (len >= MAX_CONFIG_LEN) {
Jason Wesself2d937f2008-04-17 20:05:37 +0200240 printk(KERN_ERR "kgdboc: config string too long\n");
241 return -ENOSPC;
242 }
243
244 /* Only copy in the string if the init function has not run yet */
245 if (configured < 0) {
246 strcpy(config, kmessage);
247 return 0;
248 }
249
250 if (kgdb_connected) {
251 printk(KERN_ERR
252 "kgdboc: Cannot reconfigure while KGDB is connected.\n");
253
254 return -EBUSY;
255 }
256
257 strcpy(config, kmessage);
Jason Wesselc191e5a2008-02-15 14:55:52 -0600258 /* Chop out \n char as a result of echo */
Macpaul Lin6d8619272018-10-17 23:08:38 +0800259 if (len && config[len - 1] == '\n')
Jason Wesselc191e5a2008-02-15 14:55:52 -0600260 config[len - 1] = '\0';
Jason Wesself2d937f2008-04-17 20:05:37 +0200261
262 if (configured == 1)
263 cleanup_kgdboc();
264
265 /* Go and configure with the new params. */
266 return configure_kgdboc();
267}
268
Jason Wessel408a4be2010-08-05 09:22:30 -0500269static int dbg_restore_graphics;
270
Jason Wesself2d937f2008-04-17 20:05:37 +0200271static void kgdboc_pre_exp_handler(void)
272{
Jason Wessel408a4be2010-08-05 09:22:30 -0500273 if (!dbg_restore_graphics && kgdboc_use_kms) {
274 dbg_restore_graphics = 1;
275 con_debug_enter(vc_cons[fg_console].d);
276 }
Jason Wesself2d937f2008-04-17 20:05:37 +0200277 /* Increment the module count when the debugger is active */
278 if (!kgdb_connected)
279 try_module_get(THIS_MODULE);
280}
281
282static void kgdboc_post_exp_handler(void)
283{
284 /* decrement the module count when the debugger detaches */
285 if (!kgdb_connected)
286 module_put(THIS_MODULE);
Jason Wessel408a4be2010-08-05 09:22:30 -0500287 if (kgdboc_use_kms && dbg_restore_graphics) {
288 dbg_restore_graphics = 0;
289 con_debug_leave();
290 }
Dmitry Torokhov111c1822010-11-03 11:04:05 -0700291 kgdboc_restore_input();
Jason Wesself2d937f2008-04-17 20:05:37 +0200292}
293
294static struct kgdb_io kgdboc_io_ops = {
295 .name = "kgdboc",
296 .read_char = kgdboc_get_char,
297 .write_char = kgdboc_put_char,
298 .pre_exception = kgdboc_pre_exp_handler,
299 .post_exception = kgdboc_post_exp_handler,
300};
301
Jason Wessel97311912010-05-20 21:04:30 -0500302#ifdef CONFIG_KGDB_SERIAL_CONSOLE
Laura Abbott412091e2018-09-19 18:59:01 -0700303static int kgdboc_option_setup(char *opt)
304{
305 if (!opt) {
306 pr_err("config string not provided\n");
307 return -EINVAL;
308 }
309
310 if (strlen(opt) >= MAX_CONFIG_LEN) {
311 pr_err("config string too long\n");
312 return -ENOSPC;
313 }
314 strcpy(config, opt);
315
316 return 0;
317}
318
319__setup("kgdboc=", kgdboc_option_setup);
320
321
Jason Wessel97311912010-05-20 21:04:30 -0500322/* This is only available if kgdboc is a built in for early debugging */
Jason Wessel91b152a2010-08-23 09:20:14 -0500323static int __init kgdboc_early_init(char *opt)
Jason Wessel97311912010-05-20 21:04:30 -0500324{
325 /* save the first character of the config string because the
326 * init routine can destroy it.
327 */
328 char save_ch;
329
330 kgdboc_option_setup(opt);
331 save_ch = config[0];
332 init_kgdboc();
333 config[0] = save_ch;
334 return 0;
335}
336
337early_param("ekgdboc", kgdboc_early_init);
338#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
339
Jason Wesself2d937f2008-04-17 20:05:37 +0200340module_init(init_kgdboc);
341module_exit(cleanup_kgdboc);
342module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
343MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
344MODULE_DESCRIPTION("KGDB Console TTY Driver");
345MODULE_LICENSE("GPL");