Commit | Line | Data |
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e3b3d0f5 | 1 | // SPDX-License-Identifier: GPL-2.0 |
f2d937f3 JW |
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. | |
f2d937f3 JW |
10 | */ |
11 | #include <linux/kernel.h> | |
12 | #include <linux/ctype.h> | |
13 | #include <linux/kgdb.h> | |
ada64e4c | 14 | #include <linux/kdb.h> |
f2d937f3 | 15 | #include <linux/tty.h> |
efe2f29e | 16 | #include <linux/console.h> |
408a4be1 | 17 | #include <linux/vt_kern.h> |
111c1823 | 18 | #include <linux/input.h> |
578b9ce0 | 19 | #include <linux/module.h> |
f2d937f3 JW |
20 | |
21 | #define MAX_CONFIG_LEN 40 | |
22 | ||
23 | static struct kgdb_io kgdboc_io_ops; | |
24 | ||
25 | /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */ | |
26 | static int configured = -1; | |
27 | ||
28 | static char config[MAX_CONFIG_LEN]; | |
29 | static struct kparam_string kps = { | |
30 | .string = config, | |
31 | .maxlen = MAX_CONFIG_LEN, | |
32 | }; | |
33 | ||
408a4be1 | 34 | static int kgdboc_use_kms; /* 1 if we use kernel mode switching */ |
f2d937f3 JW |
35 | static struct tty_driver *kgdb_tty_driver; |
36 | static int kgdb_tty_line; | |
37 | ||
ada64e4c | 38 | #ifdef CONFIG_KDB_KEYBOARD |
111c1823 DT |
39 | static 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 | ||
9e03aa2f | 45 | /* Return an error - we do not want to bind, just to reset */ |
111c1823 DT |
46 | return -ENODEV; |
47 | } | |
48 | ||
49 | static void kgdboc_reset_disconnect(struct input_handle *handle) | |
50 | { | |
51 | /* We do not expect anyone to actually bind to us */ | |
52 | BUG(); | |
53 | } | |
54 | ||
55 | static 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 | ||
63 | static 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 | ||
70 | static DEFINE_MUTEX(kgdboc_reset_mutex); | |
71 | ||
72 | static 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 | ||
87 | static DECLARE_WORK(kgdboc_restore_input_work, kgdboc_restore_input_helper); | |
88 | ||
89 | static void kgdboc_restore_input(void) | |
90 | { | |
8863ada9 JW |
91 | if (likely(system_state == SYSTEM_RUNNING)) |
92 | schedule_work(&kgdboc_restore_input_work); | |
111c1823 DT |
93 | } |
94 | ||
ada64e4c JW |
95 | static int kgdboc_register_kbd(char **cptr) |
96 | { | |
24b8592e JW |
97 | if (strncmp(*cptr, "kbd", 3) == 0 || |
98 | strncmp(*cptr, "kdb", 3) == 0) { | |
ada64e4c JW |
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 | ||
111 | static 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 | } | |
43829731 | 123 | flush_work(&kgdboc_restore_input_work); |
ada64e4c JW |
124 | } |
125 | #else /* ! CONFIG_KDB_KEYBOARD */ | |
126 | #define kgdboc_register_kbd(x) 0 | |
127 | #define kgdboc_unregister_kbd() | |
111c1823 | 128 | #define kgdboc_restore_input() |
ada64e4c JW |
129 | #endif /* ! CONFIG_KDB_KEYBOARD */ |
130 | ||
f2d937f3 JW |
131 | static int kgdboc_option_setup(char *opt) |
132 | { | |
adb4b83c | 133 | if (strlen(opt) >= MAX_CONFIG_LEN) { |
f2d937f3 JW |
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 | ||
ada64e4c JW |
144 | static void cleanup_kgdboc(void) |
145 | { | |
0c57dfcc AV |
146 | if (kgdb_unregister_nmi_console()) |
147 | return; | |
ada64e4c JW |
148 | kgdboc_unregister_kbd(); |
149 | if (configured == 1) | |
150 | kgdb_unregister_io_module(&kgdboc_io_ops); | |
151 | } | |
152 | ||
f2d937f3 JW |
153 | static int configure_kgdboc(void) |
154 | { | |
155 | struct tty_driver *p; | |
156 | int tty_line = 0; | |
157 | int err; | |
ada64e4c | 158 | char *cptr = config; |
efe2f29e | 159 | struct console *cons; |
f2d937f3 JW |
160 | |
161 | err = kgdboc_option_setup(config); | |
162 | if (err || !strlen(config) || isspace(config[0])) | |
163 | goto noconfig; | |
164 | ||
165 | err = -ENODEV; | |
efe2f29e | 166 | kgdboc_io_ops.is_console = 0; |
ada64e4c JW |
167 | kgdb_tty_driver = NULL; |
168 | ||
408a4be1 JW |
169 | kgdboc_use_kms = 0; |
170 | if (strncmp(cptr, "kms,", 4) == 0) { | |
171 | cptr += 4; | |
172 | kgdboc_use_kms = 1; | |
173 | } | |
174 | ||
ada64e4c JW |
175 | if (kgdboc_register_kbd(&cptr)) |
176 | goto do_register; | |
f2d937f3 | 177 | |
ada64e4c | 178 | p = tty_find_polling_driver(cptr, &tty_line); |
f2d937f3 JW |
179 | if (!p) |
180 | goto noconfig; | |
181 | ||
efe2f29e JW |
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 | ||
f2d937f3 JW |
193 | kgdb_tty_driver = p; |
194 | kgdb_tty_line = tty_line; | |
195 | ||
ada64e4c | 196 | do_register: |
f2d937f3 JW |
197 | err = kgdb_register_io_module(&kgdboc_io_ops); |
198 | if (err) | |
199 | goto noconfig; | |
200 | ||
0c57dfcc AV |
201 | err = kgdb_register_nmi_console(); |
202 | if (err) | |
203 | goto nmi_con_failed; | |
204 | ||
f2d937f3 JW |
205 | configured = 1; |
206 | ||
207 | return 0; | |
208 | ||
0c57dfcc AV |
209 | nmi_con_failed: |
210 | kgdb_unregister_io_module(&kgdboc_io_ops); | |
f2d937f3 | 211 | noconfig: |
0c57dfcc | 212 | kgdboc_unregister_kbd(); |
f2d937f3 JW |
213 | config[0] = 0; |
214 | configured = 0; | |
ada64e4c | 215 | cleanup_kgdboc(); |
f2d937f3 JW |
216 | |
217 | return err; | |
218 | } | |
219 | ||
220 | static int __init init_kgdboc(void) | |
221 | { | |
222 | /* Already configured? */ | |
223 | if (configured == 1) | |
224 | return 0; | |
225 | ||
226 | return configure_kgdboc(); | |
227 | } | |
228 | ||
f2d937f3 JW |
229 | static int kgdboc_get_char(void) |
230 | { | |
ada64e4c JW |
231 | if (!kgdb_tty_driver) |
232 | return -1; | |
f34d7a5b AC |
233 | return kgdb_tty_driver->ops->poll_get_char(kgdb_tty_driver, |
234 | kgdb_tty_line); | |
f2d937f3 JW |
235 | } |
236 | ||
237 | static void kgdboc_put_char(u8 chr) | |
238 | { | |
ada64e4c JW |
239 | if (!kgdb_tty_driver) |
240 | return; | |
f34d7a5b AC |
241 | kgdb_tty_driver->ops->poll_put_char(kgdb_tty_driver, |
242 | kgdb_tty_line, chr); | |
f2d937f3 JW |
243 | } |
244 | ||
e4dca7b7 KC |
245 | static int param_set_kgdboc_var(const char *kmessage, |
246 | const struct kernel_param *kp) | |
f2d937f3 | 247 | { |
c191e5ad JW |
248 | int len = strlen(kmessage); |
249 | ||
250 | if (len >= MAX_CONFIG_LEN) { | |
f2d937f3 JW |
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); | |
c191e5ad JW |
269 | /* Chop out \n char as a result of echo */ |
270 | if (config[len - 1] == '\n') | |
271 | config[len - 1] = '\0'; | |
f2d937f3 JW |
272 | |
273 | if (configured == 1) | |
274 | cleanup_kgdboc(); | |
275 | ||
276 | /* Go and configure with the new params. */ | |
277 | return configure_kgdboc(); | |
278 | } | |
279 | ||
408a4be1 JW |
280 | static int dbg_restore_graphics; |
281 | ||
f2d937f3 JW |
282 | static void kgdboc_pre_exp_handler(void) |
283 | { | |
408a4be1 JW |
284 | if (!dbg_restore_graphics && kgdboc_use_kms) { |
285 | dbg_restore_graphics = 1; | |
286 | con_debug_enter(vc_cons[fg_console].d); | |
287 | } | |
f2d937f3 JW |
288 | /* Increment the module count when the debugger is active */ |
289 | if (!kgdb_connected) | |
290 | try_module_get(THIS_MODULE); | |
291 | } | |
292 | ||
293 | static 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); | |
408a4be1 JW |
298 | if (kgdboc_use_kms && dbg_restore_graphics) { |
299 | dbg_restore_graphics = 0; | |
300 | con_debug_leave(); | |
301 | } | |
111c1823 | 302 | kgdboc_restore_input(); |
f2d937f3 JW |
303 | } |
304 | ||
305 | static 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 | ||
9731191f JW |
313 | #ifdef CONFIG_KGDB_SERIAL_CONSOLE |
314 | /* This is only available if kgdboc is a built in for early debugging */ | |
91b152aa | 315 | static int __init kgdboc_early_init(char *opt) |
9731191f JW |
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 | ||
329 | early_param("ekgdboc", kgdboc_early_init); | |
330 | #endif /* CONFIG_KGDB_SERIAL_CONSOLE */ | |
331 | ||
f2d937f3 JW |
332 | module_init(init_kgdboc); |
333 | module_exit(cleanup_kgdboc); | |
334 | module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644); | |
335 | MODULE_PARM_DESC(kgdboc, "<serial_device>[,baud]"); | |
336 | MODULE_DESCRIPTION("KGDB Console TTY Driver"); | |
337 | MODULE_LICENSE("GPL"); |