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