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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");
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");