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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Based on the same principle as kgdboe using the NETPOLL api, this
4 * driver uses a console polling api to implement a gdb serial inteface
5 * which is multiplexed on a console port.
6 *
7 * Maintainer: Jason Wessel <jason.wessel@windriver.com>
8 *
9 * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc.
10 */
11
12#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13
14#include <linux/kernel.h>
15#include <linux/ctype.h>
16#include <linux/kgdb.h>
17#include <linux/kdb.h>
18#include <linux/tty.h>
19#include <linux/console.h>
20#include <linux/vt_kern.h>
21#include <linux/input.h>
22#include <linux/module.h>
23
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
37static int kgdboc_use_kms; /* 1 if we use kernel mode switching */
38static struct tty_driver *kgdb_tty_driver;
39static int kgdb_tty_line;
40
41#ifdef CONFIG_KDB_KEYBOARD
42static 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
48 /* Return an error - we do not want to bind, just to reset */
49 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{
94 if (likely(system_state == SYSTEM_RUNNING))
95 schedule_work(&kgdboc_restore_input_work);
96}
97
98static int kgdboc_register_kbd(char **cptr)
99{
100 if (strncmp(*cptr, "kbd", 3) == 0 ||
101 strncmp(*cptr, "kdb", 3) == 0) {
102 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 }
126 flush_work(&kgdboc_restore_input_work);
127}
128#else /* ! CONFIG_KDB_KEYBOARD */
129#define kgdboc_register_kbd(x) 0
130#define kgdboc_unregister_kbd()
131#define kgdboc_restore_input()
132#endif /* ! CONFIG_KDB_KEYBOARD */
133
134static void cleanup_kgdboc(void)
135{
136 if (kgdb_unregister_nmi_console())
137 return;
138 kgdboc_unregister_kbd();
139 if (configured == 1)
140 kgdb_unregister_io_module(&kgdboc_io_ops);
141}
142
143static int configure_kgdboc(void)
144{
145 struct tty_driver *p;
146 int tty_line = 0;
147 int err = -ENODEV;
148 char *cptr = config;
149 struct console *cons;
150
151 if (!strlen(config) || isspace(config[0])) {
152 err = 0;
153 goto noconfig;
154 }
155
156 kgdboc_io_ops.is_console = 0;
157 kgdb_tty_driver = NULL;
158
159 kgdboc_use_kms = 0;
160 if (strncmp(cptr, "kms,", 4) == 0) {
161 cptr += 4;
162 kgdboc_use_kms = 1;
163 }
164
165 if (kgdboc_register_kbd(&cptr))
166 goto do_register;
167
168 p = tty_find_polling_driver(cptr, &tty_line);
169 if (!p)
170 goto noconfig;
171
172 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
183 kgdb_tty_driver = p;
184 kgdb_tty_line = tty_line;
185
186do_register:
187 err = kgdb_register_io_module(&kgdboc_io_ops);
188 if (err)
189 goto noconfig;
190
191 err = kgdb_register_nmi_console();
192 if (err)
193 goto nmi_con_failed;
194
195 configured = 1;
196
197 return 0;
198
199nmi_con_failed:
200 kgdb_unregister_io_module(&kgdboc_io_ops);
201noconfig:
202 kgdboc_unregister_kbd();
203 config[0] = 0;
204 configured = 0;
205 cleanup_kgdboc();
206
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
219static int kgdboc_get_char(void)
220{
221 if (!kgdb_tty_driver)
222 return -1;
223 return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
224 kgdb_tty_line);
225}
226
227static void kgdboc_put_char(u8 chr)
228{
229 if (!kgdb_tty_driver)
230 return;
231 kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
232 kgdb_tty_line, chr);
233}
234
235static int param_set_kgdboc_var(const char *kmessage,
236 const struct kernel_param *kp)
237{
238 size_t len = strlen(kmessage);
239
240 if (len >= MAX_CONFIG_LEN) {
241 pr_err("config string too long\n");
242 return -ENOSPC;
243 }
244
245 /* Only copy in the string if the init function has not run yet */
246 if (configured < 0) {
247 strcpy(config, kmessage);
248 return 0;
249 }
250
251 if (kgdb_connected) {
252 pr_err("Cannot reconfigure while KGDB is connected.\n");
253
254 return -EBUSY;
255 }
256
257 strcpy(config, kmessage);
258 /* Chop out \n char as a result of echo */
259 if (len && config[len - 1] == '\n')
260 config[len - 1] = '\0';
261
262 if (configured == 1)
263 cleanup_kgdboc();
264
265 /* Go and configure with the new params. */
266 return configure_kgdboc();
267}
268
269static int dbg_restore_graphics;
270
271static void kgdboc_pre_exp_handler(void)
272{
273 if (!dbg_restore_graphics && kgdboc_use_kms) {
274 dbg_restore_graphics = 1;
275 con_debug_enter(vc_cons[fg_console].d);
276 }
277 /* Increment the module count when the debugger is active */
278 if (!kgdb_connected)
279 try_module_get(THIS_MODULE);
280
281 atomic_inc(&ignore_console_lock_warning);
282}
283
284static void kgdboc_post_exp_handler(void)
285{
286 atomic_dec(&ignore_console_lock_warning);
287
288 /* decrement the module count when the debugger detaches */
289 if (!kgdb_connected)
290 module_put(THIS_MODULE);
291 if (kgdboc_use_kms && dbg_restore_graphics) {
292 dbg_restore_graphics = 0;
293 con_debug_leave();
294 }
295 kgdboc_restore_input();
296}
297
298static struct kgdb_io kgdboc_io_ops = {
299 .name = "kgdboc",
300 .read_char = kgdboc_get_char,
301 .write_char = kgdboc_put_char,
302 .pre_exception = kgdboc_pre_exp_handler,
303 .post_exception = kgdboc_post_exp_handler,
304};
305
306#ifdef CONFIG_KGDB_SERIAL_CONSOLE
307static int kgdboc_option_setup(char *opt)
308{
309 if (!opt) {
310 pr_err("config string not provided\n");
311 return -EINVAL;
312 }
313
314 if (strlen(opt) >= MAX_CONFIG_LEN) {
315 pr_err("config string too long\n");
316 return -ENOSPC;
317 }
318 strcpy(config, opt);
319
320 return 0;
321}
322
323__setup("kgdboc=", kgdboc_option_setup);
324
325
326/* This is only available if kgdboc is a built in for early debugging */
327static int __init kgdboc_early_init(char *opt)
328{
329 /* save the first character of the config string because the
330 * init routine can destroy it.
331 */
332 char save_ch;
333
334 kgdboc_option_setup(opt);
335 save_ch = config[0];
336 init_kgdboc();
337 config[0] = save_ch;
338 return 0;
339}
340
341early_param("ekgdboc", kgdboc_early_init);
342#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
343
344module_init(init_kgdboc);
345module_exit(cleanup_kgdboc);
346module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
347MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
348MODULE_DESCRIPTION("KGDB Console TTY Driver");
349MODULE_LICENSE("GPL");
1/*
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>
17#include <linux/kdb.h>
18#include <linux/tty.h>
19#include <linux/console.h>
20#include <linux/vt_kern.h>
21#include <linux/input.h>
22
23#define MAX_CONFIG_LEN 40
24
25static struct kgdb_io kgdboc_io_ops;
26
27/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */
28static int configured = -1;
29
30static char config[MAX_CONFIG_LEN];
31static struct kparam_string kps = {
32 .string = config,
33 .maxlen = MAX_CONFIG_LEN,
34};
35
36static int kgdboc_use_kms; /* 1 if we use kernel mode switching */
37static struct tty_driver *kgdb_tty_driver;
38static int kgdb_tty_line;
39
40#ifdef CONFIG_KDB_KEYBOARD
41static int kgdboc_reset_connect(struct input_handler *handler,
42 struct input_dev *dev,
43 const struct input_device_id *id)
44{
45 input_reset_device(dev);
46
47 /* Retrun an error - we do not want to bind, just to reset */
48 return -ENODEV;
49}
50
51static void kgdboc_reset_disconnect(struct input_handle *handle)
52{
53 /* We do not expect anyone to actually bind to us */
54 BUG();
55}
56
57static const struct input_device_id kgdboc_reset_ids[] = {
58 {
59 .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
60 .evbit = { BIT_MASK(EV_KEY) },
61 },
62 { }
63};
64
65static struct input_handler kgdboc_reset_handler = {
66 .connect = kgdboc_reset_connect,
67 .disconnect = kgdboc_reset_disconnect,
68 .name = "kgdboc_reset",
69 .id_table = kgdboc_reset_ids,
70};
71
72static DEFINE_MUTEX(kgdboc_reset_mutex);
73
74static void kgdboc_restore_input_helper(struct work_struct *dummy)
75{
76 /*
77 * We need to take a mutex to prevent several instances of
78 * this work running on different CPUs so they don't try
79 * to register again already registered handler.
80 */
81 mutex_lock(&kgdboc_reset_mutex);
82
83 if (input_register_handler(&kgdboc_reset_handler) == 0)
84 input_unregister_handler(&kgdboc_reset_handler);
85
86 mutex_unlock(&kgdboc_reset_mutex);
87}
88
89static DECLARE_WORK(kgdboc_restore_input_work, kgdboc_restore_input_helper);
90
91static void kgdboc_restore_input(void)
92{
93 if (likely(system_state == SYSTEM_RUNNING))
94 schedule_work(&kgdboc_restore_input_work);
95}
96
97static int kgdboc_register_kbd(char **cptr)
98{
99 if (strncmp(*cptr, "kbd", 3) == 0) {
100 if (kdb_poll_idx < KDB_POLL_FUNC_MAX) {
101 kdb_poll_funcs[kdb_poll_idx] = kdb_get_kbd_char;
102 kdb_poll_idx++;
103 if (cptr[0][3] == ',')
104 *cptr += 4;
105 else
106 return 1;
107 }
108 }
109 return 0;
110}
111
112static void kgdboc_unregister_kbd(void)
113{
114 int i;
115
116 for (i = 0; i < kdb_poll_idx; i++) {
117 if (kdb_poll_funcs[i] == kdb_get_kbd_char) {
118 kdb_poll_idx--;
119 kdb_poll_funcs[i] = kdb_poll_funcs[kdb_poll_idx];
120 kdb_poll_funcs[kdb_poll_idx] = NULL;
121 i--;
122 }
123 }
124 flush_work_sync(&kgdboc_restore_input_work);
125}
126#else /* ! CONFIG_KDB_KEYBOARD */
127#define kgdboc_register_kbd(x) 0
128#define kgdboc_unregister_kbd()
129#define kgdboc_restore_input()
130#endif /* ! CONFIG_KDB_KEYBOARD */
131
132static int kgdboc_option_setup(char *opt)
133{
134 if (strlen(opt) >= MAX_CONFIG_LEN) {
135 printk(KERN_ERR "kgdboc: config string too long\n");
136 return -ENOSPC;
137 }
138 strcpy(config, opt);
139
140 return 0;
141}
142
143__setup("kgdboc=", kgdboc_option_setup);
144
145static void cleanup_kgdboc(void)
146{
147 kgdboc_unregister_kbd();
148 if (configured == 1)
149 kgdb_unregister_io_module(&kgdboc_io_ops);
150}
151
152static int configure_kgdboc(void)
153{
154 struct tty_driver *p;
155 int tty_line = 0;
156 int err;
157 char *cptr = config;
158 struct console *cons;
159
160 err = kgdboc_option_setup(config);
161 if (err || !strlen(config) || isspace(config[0]))
162 goto noconfig;
163
164 err = -ENODEV;
165 kgdboc_io_ops.is_console = 0;
166 kgdb_tty_driver = NULL;
167
168 kgdboc_use_kms = 0;
169 if (strncmp(cptr, "kms,", 4) == 0) {
170 cptr += 4;
171 kgdboc_use_kms = 1;
172 }
173
174 if (kgdboc_register_kbd(&cptr))
175 goto do_register;
176
177 p = tty_find_polling_driver(cptr, &tty_line);
178 if (!p)
179 goto noconfig;
180
181 cons = console_drivers;
182 while (cons) {
183 int idx;
184 if (cons->device && cons->device(cons, &idx) == p &&
185 idx == tty_line) {
186 kgdboc_io_ops.is_console = 1;
187 break;
188 }
189 cons = cons->next;
190 }
191
192 kgdb_tty_driver = p;
193 kgdb_tty_line = tty_line;
194
195do_register:
196 err = kgdb_register_io_module(&kgdboc_io_ops);
197 if (err)
198 goto noconfig;
199
200 configured = 1;
201
202 return 0;
203
204noconfig:
205 config[0] = 0;
206 configured = 0;
207 cleanup_kgdboc();
208
209 return err;
210}
211
212static int __init init_kgdboc(void)
213{
214 /* Already configured? */
215 if (configured == 1)
216 return 0;
217
218 return configure_kgdboc();
219}
220
221static int kgdboc_get_char(void)
222{
223 if (!kgdb_tty_driver)
224 return -1;
225 return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver,
226 kgdb_tty_line);
227}
228
229static void kgdboc_put_char(u8 chr)
230{
231 if (!kgdb_tty_driver)
232 return;
233 kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver,
234 kgdb_tty_line, chr);
235}
236
237static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp)
238{
239 int len = strlen(kmessage);
240
241 if (len >= MAX_CONFIG_LEN) {
242 printk(KERN_ERR "kgdboc: config string too long\n");
243 return -ENOSPC;
244 }
245
246 /* Only copy in the string if the init function has not run yet */
247 if (configured < 0) {
248 strcpy(config, kmessage);
249 return 0;
250 }
251
252 if (kgdb_connected) {
253 printk(KERN_ERR
254 "kgdboc: Cannot reconfigure while KGDB is connected.\n");
255
256 return -EBUSY;
257 }
258
259 strcpy(config, kmessage);
260 /* Chop out \n char as a result of echo */
261 if (config[len - 1] == '\n')
262 config[len - 1] = '\0';
263
264 if (configured == 1)
265 cleanup_kgdboc();
266
267 /* Go and configure with the new params. */
268 return configure_kgdboc();
269}
270
271static int dbg_restore_graphics;
272
273static void kgdboc_pre_exp_handler(void)
274{
275 if (!dbg_restore_graphics && kgdboc_use_kms) {
276 dbg_restore_graphics = 1;
277 con_debug_enter(vc_cons[fg_console].d);
278 }
279 /* Increment the module count when the debugger is active */
280 if (!kgdb_connected)
281 try_module_get(THIS_MODULE);
282}
283
284static void kgdboc_post_exp_handler(void)
285{
286 /* decrement the module count when the debugger detaches */
287 if (!kgdb_connected)
288 module_put(THIS_MODULE);
289 if (kgdboc_use_kms && dbg_restore_graphics) {
290 dbg_restore_graphics = 0;
291 con_debug_leave();
292 }
293 kgdboc_restore_input();
294}
295
296static struct kgdb_io kgdboc_io_ops = {
297 .name = "kgdboc",
298 .read_char = kgdboc_get_char,
299 .write_char = kgdboc_put_char,
300 .pre_exception = kgdboc_pre_exp_handler,
301 .post_exception = kgdboc_post_exp_handler,
302};
303
304#ifdef CONFIG_KGDB_SERIAL_CONSOLE
305/* This is only available if kgdboc is a built in for early debugging */
306static int __init kgdboc_early_init(char *opt)
307{
308 /* save the first character of the config string because the
309 * init routine can destroy it.
310 */
311 char save_ch;
312
313 kgdboc_option_setup(opt);
314 save_ch = config[0];
315 init_kgdboc();
316 config[0] = save_ch;
317 return 0;
318}
319
320early_param("ekgdboc", kgdboc_early_init);
321#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
322
323module_init(init_kgdboc);
324module_exit(cleanup_kgdboc);
325module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
326MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]");
327MODULE_DESCRIPTION("KGDB Console TTY Driver");
328MODULE_LICENSE("GPL");