xref: /linux/drivers/tty/vt/vt.c (revision 9f90a4ddef4e4d3aa4229f6b117d4e57231457b3)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright (C) 1991, 1992  Linus Torvalds
4  */
5 
6 /*
7  * Hopefully this will be a rather complete VT102 implementation.
8  *
9  * Beeping thanks to John T Kohl.
10  *
11  * Virtual Consoles, Screen Blanking, Screen Dumping, Color, Graphics
12  *   Chars, and VT100 enhancements by Peter MacDonald.
13  *
14  * Copy and paste function by Andrew Haylett,
15  *   some enhancements by Alessandro Rubini.
16  *
17  * Code to check for different video-cards mostly by Galen Hunt,
18  * <g-hunt@ee.utah.edu>
19  *
20  * Rudimentary ISO 10646/Unicode/UTF-8 character set support by
21  * Markus Kuhn, <mskuhn@immd4.informatik.uni-erlangen.de>.
22  *
23  * Dynamic allocation of consoles, aeb@cwi.nl, May 1994
24  * Resizing of consoles, aeb, 940926
25  *
26  * Code for xterm like mouse click reporting by Peter Orbaek 20-Jul-94
27  * <poe@daimi.aau.dk>
28  *
29  * User-defined bell sound, new setterm control sequences and printk
30  * redirection by Martin Mares <mj@k332.feld.cvut.cz> 19-Nov-95
31  *
32  * APM screenblank bug fixed Takashi Manabe <manabe@roy.dsl.tutics.tut.jp>
33  *
34  * Merge with the abstract console driver by Geert Uytterhoeven
35  * <geert@linux-m68k.org>, Jan 1997.
36  *
37  *   Original m68k console driver modifications by
38  *
39  *     - Arno Griffioen <arno@usn.nl>
40  *     - David Carter <carter@cs.bris.ac.uk>
41  *
42  *   The abstract console driver provides a generic interface for a text
43  *   console. It supports VGA text mode, frame buffer based graphical consoles
44  *   and special graphics processors that are only accessible through some
45  *   registers (e.g. a TMS340x0 GSP).
46  *
47  *   The interface to the hardware is specified using a special structure
48  *   (struct consw) which contains function pointers to console operations
49  *   (see <linux/console.h> for more information).
50  *
51  * Support for changeable cursor shape
52  * by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>, August 1997
53  *
54  * Ported to i386 and con_scrolldelta fixed
55  * by Emmanuel Marty <core@ggi-project.org>, April 1998
56  *
57  * Resurrected character buffers in videoram plus lots of other trickery
58  * by Martin Mares <mj@atrey.karlin.mff.cuni.cz>, July 1998
59  *
60  * Removed old-style timers, introduced console_timer, made timer
61  * deletion SMP-safe.  17Jun00, Andrew Morton
62  *
63  * Removed console_lock, enabled interrupts across all console operations
64  * 13 March 2001, Andrew Morton
65  *
66  * Fixed UTF-8 mode so alternate charset modes always work according
67  * to control sequences interpreted in do_con_trol function
68  * preserving backward VT100 semigraphics compatibility,
69  * malformed UTF sequences represented as sequences of replacement glyphs,
70  * original codes or '?' as a last resort if replacement glyph is undefined
71  * by Adam Tla/lka <atlka@pg.gda.pl>, Aug 2006
72  */
73 
74 #include <linux/module.h>
75 #include <linux/types.h>
76 #include <linux/sched/signal.h>
77 #include <linux/tty.h>
78 #include <linux/tty_flip.h>
79 #include <linux/kernel.h>
80 #include <linux/string.h>
81 #include <linux/errno.h>
82 #include <linux/kd.h>
83 #include <linux/slab.h>
84 #include <linux/vmalloc.h>
85 #include <linux/major.h>
86 #include <linux/mm.h>
87 #include <linux/console.h>
88 #include <linux/init.h>
89 #include <linux/mutex.h>
90 #include <linux/vt_kern.h>
91 #include <linux/selection.h>
92 #include <linux/tiocl.h>
93 #include <linux/kbd_kern.h>
94 #include <linux/consolemap.h>
95 #include <linux/timer.h>
96 #include <linux/interrupt.h>
97 #include <linux/workqueue.h>
98 #include <linux/pm.h>
99 #include <linux/font.h>
100 #include <linux/bitops.h>
101 #include <linux/notifier.h>
102 #include <linux/device.h>
103 #include <linux/io.h>
104 #include <linux/uaccess.h>
105 #include <linux/kdb.h>
106 #include <linux/ctype.h>
107 #include <linux/bsearch.h>
108 #include <linux/gcd.h>
109 
110 #define MAX_NR_CON_DRIVER 16
111 
112 #define CON_DRIVER_FLAG_MODULE 1
113 #define CON_DRIVER_FLAG_INIT   2
114 #define CON_DRIVER_FLAG_ATTR   4
115 #define CON_DRIVER_FLAG_ZOMBIE 8
116 
117 struct con_driver {
118 	const struct consw *con;
119 	const char *desc;
120 	struct device *dev;
121 	int node;
122 	int first;
123 	int last;
124 	int flag;
125 };
126 
127 static struct con_driver registered_con_driver[MAX_NR_CON_DRIVER];
128 const struct consw *conswitchp;
129 
130 /*
131  * Here is the default bell parameters: 750HZ, 1/8th of a second
132  */
133 #define DEFAULT_BELL_PITCH	750
134 #define DEFAULT_BELL_DURATION	(HZ/8)
135 #define DEFAULT_CURSOR_BLINK_MS	200
136 
137 struct vc vc_cons [MAX_NR_CONSOLES];
138 
139 #ifndef VT_SINGLE_DRIVER
140 static const struct consw *con_driver_map[MAX_NR_CONSOLES];
141 #endif
142 
143 static int con_open(struct tty_struct *, struct file *);
144 static void vc_init(struct vc_data *vc, unsigned int rows,
145 		    unsigned int cols, int do_clear);
146 static void gotoxy(struct vc_data *vc, int new_x, int new_y);
147 static void save_cur(struct vc_data *vc);
148 static void reset_terminal(struct vc_data *vc, int do_clear);
149 static void con_flush_chars(struct tty_struct *tty);
150 static int set_vesa_blanking(char __user *p);
151 static void set_cursor(struct vc_data *vc);
152 static void hide_cursor(struct vc_data *vc);
153 static void console_callback(struct work_struct *ignored);
154 static void con_driver_unregister_callback(struct work_struct *ignored);
155 static void blank_screen_t(struct timer_list *unused);
156 static void set_palette(struct vc_data *vc);
157 
158 #define vt_get_kmsg_redirect() vt_kmsg_redirect(-1)
159 
160 static int printable;		/* Is console ready for printing? */
161 int default_utf8 = true;
162 module_param(default_utf8, int, S_IRUGO | S_IWUSR);
163 int global_cursor_default = -1;
164 module_param(global_cursor_default, int, S_IRUGO | S_IWUSR);
165 
166 static int cur_default = CUR_UNDERLINE;
167 module_param(cur_default, int, S_IRUGO | S_IWUSR);
168 
169 /*
170  * ignore_poke: don't unblank the screen when things are typed.  This is
171  * mainly for the privacy of braille terminal users.
172  */
173 static int ignore_poke;
174 
175 int do_poke_blanked_console;
176 int console_blanked;
177 
178 static int vesa_blank_mode; /* 0:none 1:suspendV 2:suspendH 3:powerdown */
179 static int vesa_off_interval;
180 static int blankinterval;
181 core_param(consoleblank, blankinterval, int, 0444);
182 
183 static DECLARE_WORK(console_work, console_callback);
184 static DECLARE_WORK(con_driver_unregister_work, con_driver_unregister_callback);
185 
186 /*
187  * fg_console is the current virtual console,
188  * last_console is the last used one,
189  * want_console is the console we want to switch to,
190  * saved_* variants are for save/restore around kernel debugger enter/leave
191  */
192 int fg_console;
193 int last_console;
194 int want_console = -1;
195 static int saved_fg_console;
196 static int saved_last_console;
197 static int saved_want_console;
198 static int saved_vc_mode;
199 static int saved_console_blanked;
200 
201 /*
202  * For each existing display, we have a pointer to console currently visible
203  * on that display, allowing consoles other than fg_console to be refreshed
204  * appropriately. Unless the low-level driver supplies its own display_fg
205  * variable, we use this one for the "master display".
206  */
207 static struct vc_data *master_display_fg;
208 
209 /*
210  * Unfortunately, we need to delay tty echo when we're currently writing to the
211  * console since the code is (and always was) not re-entrant, so we schedule
212  * all flip requests to process context with schedule-task() and run it from
213  * console_callback().
214  */
215 
216 /*
217  * For the same reason, we defer scrollback to the console callback.
218  */
219 static int scrollback_delta;
220 
221 /*
222  * Hook so that the power management routines can (un)blank
223  * the console on our behalf.
224  */
225 int (*console_blank_hook)(int);
226 
227 static DEFINE_TIMER(console_timer, blank_screen_t);
228 static int blank_state;
229 static int blank_timer_expired;
230 enum {
231 	blank_off = 0,
232 	blank_normal_wait,
233 	blank_vesa_wait,
234 };
235 
236 /*
237  * /sys/class/tty/tty0/
238  *
239  * the attribute 'active' contains the name of the current vc
240  * console and it supports poll() to detect vc switches
241  */
242 static struct device *tty0dev;
243 
244 /*
245  * Notifier list for console events.
246  */
247 static ATOMIC_NOTIFIER_HEAD(vt_notifier_list);
248 
249 int register_vt_notifier(struct notifier_block *nb)
250 {
251 	return atomic_notifier_chain_register(&vt_notifier_list, nb);
252 }
253 EXPORT_SYMBOL_GPL(register_vt_notifier);
254 
255 int unregister_vt_notifier(struct notifier_block *nb)
256 {
257 	return atomic_notifier_chain_unregister(&vt_notifier_list, nb);
258 }
259 EXPORT_SYMBOL_GPL(unregister_vt_notifier);
260 
261 static void notify_write(struct vc_data *vc, unsigned int unicode)
262 {
263 	struct vt_notifier_param param = { .vc = vc, .c = unicode };
264 	atomic_notifier_call_chain(&vt_notifier_list, VT_WRITE, &param);
265 }
266 
267 static void notify_update(struct vc_data *vc)
268 {
269 	struct vt_notifier_param param = { .vc = vc };
270 	atomic_notifier_call_chain(&vt_notifier_list, VT_UPDATE, &param);
271 }
272 /*
273  *	Low-Level Functions
274  */
275 
276 static inline bool con_is_fg(const struct vc_data *vc)
277 {
278 	return vc->vc_num == fg_console;
279 }
280 
281 static inline bool con_should_update(const struct vc_data *vc)
282 {
283 	return con_is_visible(vc) && !console_blanked;
284 }
285 
286 static inline unsigned short *screenpos(const struct vc_data *vc, int offset,
287 		bool viewed)
288 {
289 	unsigned short *p;
290 
291 	if (!viewed)
292 		p = (unsigned short *)(vc->vc_origin + offset);
293 	else if (!vc->vc_sw->con_screen_pos)
294 		p = (unsigned short *)(vc->vc_visible_origin + offset);
295 	else
296 		p = vc->vc_sw->con_screen_pos(vc, offset);
297 	return p;
298 }
299 
300 /* Called  from the keyboard irq path.. */
301 static inline void scrolldelta(int lines)
302 {
303 	/* FIXME */
304 	/* scrolldelta needs some kind of consistency lock, but the BKL was
305 	   and still is not protecting versus the scheduled back end */
306 	scrollback_delta += lines;
307 	schedule_console_callback();
308 }
309 
310 void schedule_console_callback(void)
311 {
312 	schedule_work(&console_work);
313 }
314 
315 /*
316  * Code to manage unicode-based screen buffers
317  */
318 
319 #ifdef NO_VC_UNI_SCREEN
320 /* this disables and optimizes related code away at compile time */
321 #define get_vc_uniscr(vc) NULL
322 #else
323 #define get_vc_uniscr(vc) vc->vc_uni_screen
324 #endif
325 
326 #define VC_UNI_SCREEN_DEBUG 0
327 
328 typedef uint32_t char32_t;
329 
330 /*
331  * Our screen buffer is preceded by an array of line pointers so that
332  * scrolling only implies some pointer shuffling.
333  */
334 struct uni_screen {
335 	char32_t *lines[0];
336 };
337 
338 static struct uni_screen *vc_uniscr_alloc(unsigned int cols, unsigned int rows)
339 {
340 	struct uni_screen *uniscr;
341 	void *p;
342 	unsigned int memsize, i;
343 
344 	/* allocate everything in one go */
345 	memsize = cols * rows * sizeof(char32_t);
346 	memsize += rows * sizeof(char32_t *);
347 	p = vmalloc(memsize);
348 	if (!p)
349 		return NULL;
350 
351 	/* initial line pointers */
352 	uniscr = p;
353 	p = uniscr->lines + rows;
354 	for (i = 0; i < rows; i++) {
355 		uniscr->lines[i] = p;
356 		p += cols * sizeof(char32_t);
357 	}
358 	return uniscr;
359 }
360 
361 static void vc_uniscr_free(struct uni_screen *uniscr)
362 {
363 	vfree(uniscr);
364 }
365 
366 static void vc_uniscr_set(struct vc_data *vc, struct uni_screen *new_uniscr)
367 {
368 	vc_uniscr_free(vc->vc_uni_screen);
369 	vc->vc_uni_screen = new_uniscr;
370 }
371 
372 static void vc_uniscr_putc(struct vc_data *vc, char32_t uc)
373 {
374 	struct uni_screen *uniscr = get_vc_uniscr(vc);
375 
376 	if (uniscr)
377 		uniscr->lines[vc->state.y][vc->state.x] = uc;
378 }
379 
380 static void vc_uniscr_insert(struct vc_data *vc, unsigned int nr)
381 {
382 	struct uni_screen *uniscr = get_vc_uniscr(vc);
383 
384 	if (uniscr) {
385 		char32_t *ln = uniscr->lines[vc->state.y];
386 		unsigned int x = vc->state.x, cols = vc->vc_cols;
387 
388 		memmove(&ln[x + nr], &ln[x], (cols - x - nr) * sizeof(*ln));
389 		memset32(&ln[x], ' ', nr);
390 	}
391 }
392 
393 static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
394 {
395 	struct uni_screen *uniscr = get_vc_uniscr(vc);
396 
397 	if (uniscr) {
398 		char32_t *ln = uniscr->lines[vc->state.y];
399 		unsigned int x = vc->state.x, cols = vc->vc_cols;
400 
401 		memcpy(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
402 		memset32(&ln[cols - nr], ' ', nr);
403 	}
404 }
405 
406 static void vc_uniscr_clear_line(struct vc_data *vc, unsigned int x,
407 				 unsigned int nr)
408 {
409 	struct uni_screen *uniscr = get_vc_uniscr(vc);
410 
411 	if (uniscr) {
412 		char32_t *ln = uniscr->lines[vc->state.y];
413 
414 		memset32(&ln[x], ' ', nr);
415 	}
416 }
417 
418 static void vc_uniscr_clear_lines(struct vc_data *vc, unsigned int y,
419 				  unsigned int nr)
420 {
421 	struct uni_screen *uniscr = get_vc_uniscr(vc);
422 
423 	if (uniscr) {
424 		unsigned int cols = vc->vc_cols;
425 
426 		while (nr--)
427 			memset32(uniscr->lines[y++], ' ', cols);
428 	}
429 }
430 
431 static void vc_uniscr_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
432 			     enum con_scroll dir, unsigned int nr)
433 {
434 	struct uni_screen *uniscr = get_vc_uniscr(vc);
435 
436 	if (uniscr) {
437 		unsigned int i, j, k, sz, d, clear;
438 
439 		sz = b - t;
440 		clear = b - nr;
441 		d = nr;
442 		if (dir == SM_DOWN) {
443 			clear = t;
444 			d = sz - nr;
445 		}
446 		for (i = 0; i < gcd(d, sz); i++) {
447 			char32_t *tmp = uniscr->lines[t + i];
448 			j = i;
449 			while (1) {
450 				k = j + d;
451 				if (k >= sz)
452 					k -= sz;
453 				if (k == i)
454 					break;
455 				uniscr->lines[t + j] = uniscr->lines[t + k];
456 				j = k;
457 			}
458 			uniscr->lines[t + j] = tmp;
459 		}
460 		vc_uniscr_clear_lines(vc, clear, nr);
461 	}
462 }
463 
464 static void vc_uniscr_copy_area(struct uni_screen *dst,
465 				unsigned int dst_cols,
466 				unsigned int dst_rows,
467 				struct uni_screen *src,
468 				unsigned int src_cols,
469 				unsigned int src_top_row,
470 				unsigned int src_bot_row)
471 {
472 	unsigned int dst_row = 0;
473 
474 	if (!dst)
475 		return;
476 
477 	while (src_top_row < src_bot_row) {
478 		char32_t *src_line = src->lines[src_top_row];
479 		char32_t *dst_line = dst->lines[dst_row];
480 
481 		memcpy(dst_line, src_line, src_cols * sizeof(char32_t));
482 		if (dst_cols - src_cols)
483 			memset32(dst_line + src_cols, ' ', dst_cols - src_cols);
484 		src_top_row++;
485 		dst_row++;
486 	}
487 	while (dst_row < dst_rows) {
488 		char32_t *dst_line = dst->lines[dst_row];
489 
490 		memset32(dst_line, ' ', dst_cols);
491 		dst_row++;
492 	}
493 }
494 
495 /*
496  * Called from vcs_read() to make sure unicode screen retrieval is possible.
497  * This will initialize the unicode screen buffer if not already done.
498  * This returns 0 if OK, or a negative error code otherwise.
499  * In particular, -ENODATA is returned if the console is not in UTF-8 mode.
500  */
501 int vc_uniscr_check(struct vc_data *vc)
502 {
503 	struct uni_screen *uniscr;
504 	unsigned short *p;
505 	int x, y, mask;
506 
507 	if (__is_defined(NO_VC_UNI_SCREEN))
508 		return -EOPNOTSUPP;
509 
510 	WARN_CONSOLE_UNLOCKED();
511 
512 	if (!vc->vc_utf)
513 		return -ENODATA;
514 
515 	if (vc->vc_uni_screen)
516 		return 0;
517 
518 	uniscr = vc_uniscr_alloc(vc->vc_cols, vc->vc_rows);
519 	if (!uniscr)
520 		return -ENOMEM;
521 
522 	/*
523 	 * Let's populate it initially with (imperfect) reverse translation.
524 	 * This is the next best thing we can do short of having it enabled
525 	 * from the start even when no users rely on this functionality. True
526 	 * unicode content will be available after a complete screen refresh.
527 	 */
528 	p = (unsigned short *)vc->vc_origin;
529 	mask = vc->vc_hi_font_mask | 0xff;
530 	for (y = 0; y < vc->vc_rows; y++) {
531 		char32_t *line = uniscr->lines[y];
532 		for (x = 0; x < vc->vc_cols; x++) {
533 			u16 glyph = scr_readw(p++) & mask;
534 			line[x] = inverse_translate(vc, glyph, true);
535 		}
536 	}
537 
538 	vc->vc_uni_screen = uniscr;
539 	return 0;
540 }
541 
542 /*
543  * Called from vcs_read() to get the unicode data from the screen.
544  * This must be preceded by a successful call to vc_uniscr_check() once
545  * the console lock has been taken.
546  */
547 void vc_uniscr_copy_line(const struct vc_data *vc, void *dest, bool viewed,
548 			 unsigned int row, unsigned int col, unsigned int nr)
549 {
550 	struct uni_screen *uniscr = get_vc_uniscr(vc);
551 	int offset = row * vc->vc_size_row + col * 2;
552 	unsigned long pos;
553 
554 	BUG_ON(!uniscr);
555 
556 	pos = (unsigned long)screenpos(vc, offset, viewed);
557 	if (pos >= vc->vc_origin && pos < vc->vc_scr_end) {
558 		/*
559 		 * Desired position falls in the main screen buffer.
560 		 * However the actual row/col might be different if
561 		 * scrollback is active.
562 		 */
563 		row = (pos - vc->vc_origin) / vc->vc_size_row;
564 		col = ((pos - vc->vc_origin) % vc->vc_size_row) / 2;
565 		memcpy(dest, &uniscr->lines[row][col], nr * sizeof(char32_t));
566 	} else {
567 		/*
568 		 * Scrollback is active. For now let's simply backtranslate
569 		 * the screen glyphs until the unicode screen buffer does
570 		 * synchronize with console display drivers for a scrollback
571 		 * buffer of its own.
572 		 */
573 		u16 *p = (u16 *)pos;
574 		int mask = vc->vc_hi_font_mask | 0xff;
575 		char32_t *uni_buf = dest;
576 		while (nr--) {
577 			u16 glyph = scr_readw(p++) & mask;
578 			*uni_buf++ = inverse_translate(vc, glyph, true);
579 		}
580 	}
581 }
582 
583 /* this is for validation and debugging only */
584 static void vc_uniscr_debug_check(struct vc_data *vc)
585 {
586 	struct uni_screen *uniscr = get_vc_uniscr(vc);
587 	unsigned short *p;
588 	int x, y, mask;
589 
590 	if (!VC_UNI_SCREEN_DEBUG || !uniscr)
591 		return;
592 
593 	WARN_CONSOLE_UNLOCKED();
594 
595 	/*
596 	 * Make sure our unicode screen translates into the same glyphs
597 	 * as the actual screen. This is brutal indeed.
598 	 */
599 	p = (unsigned short *)vc->vc_origin;
600 	mask = vc->vc_hi_font_mask | 0xff;
601 	for (y = 0; y < vc->vc_rows; y++) {
602 		char32_t *line = uniscr->lines[y];
603 		for (x = 0; x < vc->vc_cols; x++) {
604 			u16 glyph = scr_readw(p++) & mask;
605 			char32_t uc = line[x];
606 			int tc = conv_uni_to_pc(vc, uc);
607 			if (tc == -4)
608 				tc = conv_uni_to_pc(vc, 0xfffd);
609 			if (tc == -4)
610 				tc = conv_uni_to_pc(vc, '?');
611 			if (tc != glyph)
612 				pr_err_ratelimited(
613 					"%s: mismatch at %d,%d: glyph=%#x tc=%#x\n",
614 					__func__, x, y, glyph, tc);
615 		}
616 	}
617 }
618 
619 
620 static void con_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
621 		enum con_scroll dir, unsigned int nr)
622 {
623 	u16 *clear, *d, *s;
624 
625 	if (t + nr >= b)
626 		nr = b - t - 1;
627 	if (b > vc->vc_rows || t >= b || nr < 1)
628 		return;
629 	vc_uniscr_scroll(vc, t, b, dir, nr);
630 	if (con_is_visible(vc) && vc->vc_sw->con_scroll(vc, t, b, dir, nr))
631 		return;
632 
633 	s = clear = (u16 *)(vc->vc_origin + vc->vc_size_row * t);
634 	d = (u16 *)(vc->vc_origin + vc->vc_size_row * (t + nr));
635 
636 	if (dir == SM_UP) {
637 		clear = s + (b - t - nr) * vc->vc_cols;
638 		swap(s, d);
639 	}
640 	scr_memmovew(d, s, (b - t - nr) * vc->vc_size_row);
641 	scr_memsetw(clear, vc->vc_video_erase_char, vc->vc_size_row * nr);
642 }
643 
644 static void do_update_region(struct vc_data *vc, unsigned long start, int count)
645 {
646 	unsigned int xx, yy, offset;
647 	u16 *p;
648 
649 	p = (u16 *) start;
650 	if (!vc->vc_sw->con_getxy) {
651 		offset = (start - vc->vc_origin) / 2;
652 		xx = offset % vc->vc_cols;
653 		yy = offset / vc->vc_cols;
654 	} else {
655 		int nxx, nyy;
656 		start = vc->vc_sw->con_getxy(vc, start, &nxx, &nyy);
657 		xx = nxx; yy = nyy;
658 	}
659 	for(;;) {
660 		u16 attrib = scr_readw(p) & 0xff00;
661 		int startx = xx;
662 		u16 *q = p;
663 		while (xx < vc->vc_cols && count) {
664 			if (attrib != (scr_readw(p) & 0xff00)) {
665 				if (p > q)
666 					vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
667 				startx = xx;
668 				q = p;
669 				attrib = scr_readw(p) & 0xff00;
670 			}
671 			p++;
672 			xx++;
673 			count--;
674 		}
675 		if (p > q)
676 			vc->vc_sw->con_putcs(vc, q, p-q, yy, startx);
677 		if (!count)
678 			break;
679 		xx = 0;
680 		yy++;
681 		if (vc->vc_sw->con_getxy) {
682 			p = (u16 *)start;
683 			start = vc->vc_sw->con_getxy(vc, start, NULL, NULL);
684 		}
685 	}
686 }
687 
688 void update_region(struct vc_data *vc, unsigned long start, int count)
689 {
690 	WARN_CONSOLE_UNLOCKED();
691 
692 	if (con_should_update(vc)) {
693 		hide_cursor(vc);
694 		do_update_region(vc, start, count);
695 		set_cursor(vc);
696 	}
697 }
698 
699 /* Structure of attributes is hardware-dependent */
700 
701 static u8 build_attr(struct vc_data *vc, u8 _color,
702 		enum vc_intensity _intensity, bool _blink, bool _underline,
703 		bool _reverse, bool _italic)
704 {
705 	if (vc->vc_sw->con_build_attr)
706 		return vc->vc_sw->con_build_attr(vc, _color, _intensity,
707 		       _blink, _underline, _reverse, _italic);
708 
709 /*
710  * ++roman: I completely changed the attribute format for monochrome
711  * mode (!can_do_color). The formerly used MDA (monochrome display
712  * adapter) format didn't allow the combination of certain effects.
713  * Now the attribute is just a bit vector:
714  *  Bit 0..1: intensity (0..2)
715  *  Bit 2   : underline
716  *  Bit 3   : reverse
717  *  Bit 7   : blink
718  */
719 	{
720 	u8 a = _color;
721 	if (!vc->vc_can_do_color)
722 		return _intensity |
723 		       (_italic    << 1) |
724 		       (_underline << 2) |
725 		       (_reverse   << 3) |
726 		       (_blink     << 7);
727 	if (_italic)
728 		a = (a & 0xF0) | vc->vc_itcolor;
729 	else if (_underline)
730 		a = (a & 0xf0) | vc->vc_ulcolor;
731 	else if (_intensity == VCI_HALF_BRIGHT)
732 		a = (a & 0xf0) | vc->vc_halfcolor;
733 	if (_reverse)
734 		a = (a & 0x88) | (((a >> 4) | (a << 4)) & 0x77);
735 	if (_blink)
736 		a ^= 0x80;
737 	if (_intensity == VCI_BOLD)
738 		a ^= 0x08;
739 	if (vc->vc_hi_font_mask == 0x100)
740 		a <<= 1;
741 	return a;
742 	}
743 }
744 
745 static void update_attr(struct vc_data *vc)
746 {
747 	vc->vc_attr = build_attr(vc, vc->state.color, vc->state.intensity,
748 	              vc->state.blink, vc->state.underline,
749 	              vc->state.reverse ^ vc->vc_decscnm, vc->state.italic);
750 	vc->vc_video_erase_char = ' ' | (build_attr(vc, vc->state.color,
751 				VCI_NORMAL, vc->state.blink, false,
752 				vc->vc_decscnm, false) << 8);
753 }
754 
755 /* Note: inverting the screen twice should revert to the original state */
756 void invert_screen(struct vc_data *vc, int offset, int count, bool viewed)
757 {
758 	unsigned short *p;
759 
760 	WARN_CONSOLE_UNLOCKED();
761 
762 	count /= 2;
763 	p = screenpos(vc, offset, viewed);
764 	if (vc->vc_sw->con_invert_region) {
765 		vc->vc_sw->con_invert_region(vc, p, count);
766 	} else {
767 		u16 *q = p;
768 		int cnt = count;
769 		u16 a;
770 
771 		if (!vc->vc_can_do_color) {
772 			while (cnt--) {
773 			    a = scr_readw(q);
774 			    a ^= 0x0800;
775 			    scr_writew(a, q);
776 			    q++;
777 			}
778 		} else if (vc->vc_hi_font_mask == 0x100) {
779 			while (cnt--) {
780 				a = scr_readw(q);
781 				a = (a & 0x11ff) |
782 				   ((a & 0xe000) >> 4) |
783 				   ((a & 0x0e00) << 4);
784 				scr_writew(a, q);
785 				q++;
786 			}
787 		} else {
788 			while (cnt--) {
789 				a = scr_readw(q);
790 				a = (a & 0x88ff) |
791 				   ((a & 0x7000) >> 4) |
792 				   ((a & 0x0700) << 4);
793 				scr_writew(a, q);
794 				q++;
795 			}
796 		}
797 	}
798 
799 	if (con_should_update(vc))
800 		do_update_region(vc, (unsigned long) p, count);
801 	notify_update(vc);
802 }
803 
804 /* used by selection: complement pointer position */
805 void complement_pos(struct vc_data *vc, int offset)
806 {
807 	static int old_offset = -1;
808 	static unsigned short old;
809 	static unsigned short oldx, oldy;
810 
811 	WARN_CONSOLE_UNLOCKED();
812 
813 	if (old_offset != -1 && old_offset >= 0 &&
814 	    old_offset < vc->vc_screenbuf_size) {
815 		scr_writew(old, screenpos(vc, old_offset, true));
816 		if (con_should_update(vc))
817 			vc->vc_sw->con_putc(vc, old, oldy, oldx);
818 		notify_update(vc);
819 	}
820 
821 	old_offset = offset;
822 
823 	if (offset != -1 && offset >= 0 &&
824 	    offset < vc->vc_screenbuf_size) {
825 		unsigned short new;
826 		unsigned short *p;
827 		p = screenpos(vc, offset, true);
828 		old = scr_readw(p);
829 		new = old ^ vc->vc_complement_mask;
830 		scr_writew(new, p);
831 		if (con_should_update(vc)) {
832 			oldx = (offset >> 1) % vc->vc_cols;
833 			oldy = (offset >> 1) / vc->vc_cols;
834 			vc->vc_sw->con_putc(vc, new, oldy, oldx);
835 		}
836 		notify_update(vc);
837 	}
838 }
839 
840 static void insert_char(struct vc_data *vc, unsigned int nr)
841 {
842 	unsigned short *p = (unsigned short *) vc->vc_pos;
843 
844 	vc_uniscr_insert(vc, nr);
845 	scr_memmovew(p + nr, p, (vc->vc_cols - vc->state.x - nr) * 2);
846 	scr_memsetw(p, vc->vc_video_erase_char, nr * 2);
847 	vc->vc_need_wrap = 0;
848 	if (con_should_update(vc))
849 		do_update_region(vc, (unsigned long) p,
850 			vc->vc_cols - vc->state.x);
851 }
852 
853 static void delete_char(struct vc_data *vc, unsigned int nr)
854 {
855 	unsigned short *p = (unsigned short *) vc->vc_pos;
856 
857 	vc_uniscr_delete(vc, nr);
858 	scr_memcpyw(p, p + nr, (vc->vc_cols - vc->state.x - nr) * 2);
859 	scr_memsetw(p + vc->vc_cols - vc->state.x - nr, vc->vc_video_erase_char,
860 			nr * 2);
861 	vc->vc_need_wrap = 0;
862 	if (con_should_update(vc))
863 		do_update_region(vc, (unsigned long) p,
864 			vc->vc_cols - vc->state.x);
865 }
866 
867 static int softcursor_original = -1;
868 
869 static void add_softcursor(struct vc_data *vc)
870 {
871 	int i = scr_readw((u16 *) vc->vc_pos);
872 	u32 type = vc->vc_cursor_type;
873 
874 	if (!(type & CUR_SW))
875 		return;
876 	if (softcursor_original != -1)
877 		return;
878 	softcursor_original = i;
879 	i |= CUR_SET(type);
880 	i ^= CUR_CHANGE(type);
881 	if ((type & CUR_ALWAYS_BG) &&
882 			(softcursor_original & CUR_BG) == (i & CUR_BG))
883 		i ^= CUR_BG;
884 	if ((type & CUR_INVERT_FG_BG) && (i & CUR_FG) == ((i & CUR_BG) >> 4))
885 		i ^= CUR_FG;
886 	scr_writew(i, (u16 *)vc->vc_pos);
887 	if (con_should_update(vc))
888 		vc->vc_sw->con_putc(vc, i, vc->state.y, vc->state.x);
889 }
890 
891 static void hide_softcursor(struct vc_data *vc)
892 {
893 	if (softcursor_original != -1) {
894 		scr_writew(softcursor_original, (u16 *)vc->vc_pos);
895 		if (con_should_update(vc))
896 			vc->vc_sw->con_putc(vc, softcursor_original,
897 					vc->state.y, vc->state.x);
898 		softcursor_original = -1;
899 	}
900 }
901 
902 static void hide_cursor(struct vc_data *vc)
903 {
904 	if (vc_is_sel(vc))
905 		clear_selection();
906 
907 	vc->vc_sw->con_cursor(vc, CM_ERASE);
908 	hide_softcursor(vc);
909 }
910 
911 static void set_cursor(struct vc_data *vc)
912 {
913 	if (!con_is_fg(vc) || console_blanked || vc->vc_mode == KD_GRAPHICS)
914 		return;
915 	if (vc->vc_deccm) {
916 		if (vc_is_sel(vc))
917 			clear_selection();
918 		add_softcursor(vc);
919 		if (CUR_SIZE(vc->vc_cursor_type) != CUR_NONE)
920 			vc->vc_sw->con_cursor(vc, CM_DRAW);
921 	} else
922 		hide_cursor(vc);
923 }
924 
925 static void set_origin(struct vc_data *vc)
926 {
927 	WARN_CONSOLE_UNLOCKED();
928 
929 	if (!con_is_visible(vc) ||
930 	    !vc->vc_sw->con_set_origin ||
931 	    !vc->vc_sw->con_set_origin(vc))
932 		vc->vc_origin = (unsigned long)vc->vc_screenbuf;
933 	vc->vc_visible_origin = vc->vc_origin;
934 	vc->vc_scr_end = vc->vc_origin + vc->vc_screenbuf_size;
935 	vc->vc_pos = vc->vc_origin + vc->vc_size_row * vc->state.y +
936 		2 * vc->state.x;
937 }
938 
939 static void save_screen(struct vc_data *vc)
940 {
941 	WARN_CONSOLE_UNLOCKED();
942 
943 	if (vc->vc_sw->con_save_screen)
944 		vc->vc_sw->con_save_screen(vc);
945 }
946 
947 static void flush_scrollback(struct vc_data *vc)
948 {
949 	WARN_CONSOLE_UNLOCKED();
950 
951 	set_origin(vc);
952 	if (vc->vc_sw->con_flush_scrollback) {
953 		vc->vc_sw->con_flush_scrollback(vc);
954 	} else if (con_is_visible(vc)) {
955 		/*
956 		 * When no con_flush_scrollback method is provided then the
957 		 * legacy way for flushing the scrollback buffer is to use
958 		 * a side effect of the con_switch method. We do it only on
959 		 * the foreground console as background consoles have no
960 		 * scrollback buffers in that case and we obviously don't
961 		 * want to switch to them.
962 		 */
963 		hide_cursor(vc);
964 		vc->vc_sw->con_switch(vc);
965 		set_cursor(vc);
966 	}
967 }
968 
969 /*
970  *	Redrawing of screen
971  */
972 
973 void clear_buffer_attributes(struct vc_data *vc)
974 {
975 	unsigned short *p = (unsigned short *)vc->vc_origin;
976 	int count = vc->vc_screenbuf_size / 2;
977 	int mask = vc->vc_hi_font_mask | 0xff;
978 
979 	for (; count > 0; count--, p++) {
980 		scr_writew((scr_readw(p)&mask) | (vc->vc_video_erase_char & ~mask), p);
981 	}
982 }
983 
984 void redraw_screen(struct vc_data *vc, int is_switch)
985 {
986 	int redraw = 0;
987 
988 	WARN_CONSOLE_UNLOCKED();
989 
990 	if (!vc) {
991 		/* strange ... */
992 		/* printk("redraw_screen: tty %d not allocated ??\n", new_console+1); */
993 		return;
994 	}
995 
996 	if (is_switch) {
997 		struct vc_data *old_vc = vc_cons[fg_console].d;
998 		if (old_vc == vc)
999 			return;
1000 		if (!con_is_visible(vc))
1001 			redraw = 1;
1002 		*vc->vc_display_fg = vc;
1003 		fg_console = vc->vc_num;
1004 		hide_cursor(old_vc);
1005 		if (!con_is_visible(old_vc)) {
1006 			save_screen(old_vc);
1007 			set_origin(old_vc);
1008 		}
1009 		if (tty0dev)
1010 			sysfs_notify(&tty0dev->kobj, NULL, "active");
1011 	} else {
1012 		hide_cursor(vc);
1013 		redraw = 1;
1014 	}
1015 
1016 	if (redraw) {
1017 		int update;
1018 		int old_was_color = vc->vc_can_do_color;
1019 
1020 		set_origin(vc);
1021 		update = vc->vc_sw->con_switch(vc);
1022 		set_palette(vc);
1023 		/*
1024 		 * If console changed from mono<->color, the best we can do
1025 		 * is to clear the buffer attributes. As it currently stands,
1026 		 * rebuilding new attributes from the old buffer is not doable
1027 		 * without overly complex code.
1028 		 */
1029 		if (old_was_color != vc->vc_can_do_color) {
1030 			update_attr(vc);
1031 			clear_buffer_attributes(vc);
1032 		}
1033 
1034 		if (update && vc->vc_mode != KD_GRAPHICS)
1035 			do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
1036 	}
1037 	set_cursor(vc);
1038 	if (is_switch) {
1039 		vt_set_leds_compute_shiftstate();
1040 		notify_update(vc);
1041 	}
1042 }
1043 
1044 /*
1045  *	Allocation, freeing and resizing of VTs.
1046  */
1047 
1048 int vc_cons_allocated(unsigned int i)
1049 {
1050 	return (i < MAX_NR_CONSOLES && vc_cons[i].d);
1051 }
1052 
1053 static void visual_init(struct vc_data *vc, int num, int init)
1054 {
1055 	/* ++Geert: vc->vc_sw->con_init determines console size */
1056 	if (vc->vc_sw)
1057 		module_put(vc->vc_sw->owner);
1058 	vc->vc_sw = conswitchp;
1059 #ifndef VT_SINGLE_DRIVER
1060 	if (con_driver_map[num])
1061 		vc->vc_sw = con_driver_map[num];
1062 #endif
1063 	__module_get(vc->vc_sw->owner);
1064 	vc->vc_num = num;
1065 	vc->vc_display_fg = &master_display_fg;
1066 	if (vc->vc_uni_pagedir_loc)
1067 		con_free_unimap(vc);
1068 	vc->vc_uni_pagedir_loc = &vc->vc_uni_pagedir;
1069 	vc->vc_uni_pagedir = NULL;
1070 	vc->vc_hi_font_mask = 0;
1071 	vc->vc_complement_mask = 0;
1072 	vc->vc_can_do_color = 0;
1073 	vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
1074 	vc->vc_sw->con_init(vc, init);
1075 	if (!vc->vc_complement_mask)
1076 		vc->vc_complement_mask = vc->vc_can_do_color ? 0x7700 : 0x0800;
1077 	vc->vc_s_complement_mask = vc->vc_complement_mask;
1078 	vc->vc_size_row = vc->vc_cols << 1;
1079 	vc->vc_screenbuf_size = vc->vc_rows * vc->vc_size_row;
1080 }
1081 
1082 
1083 static void visual_deinit(struct vc_data *vc)
1084 {
1085 	vc->vc_sw->con_deinit(vc);
1086 	module_put(vc->vc_sw->owner);
1087 }
1088 
1089 static void vc_port_destruct(struct tty_port *port)
1090 {
1091 	struct vc_data *vc = container_of(port, struct vc_data, port);
1092 
1093 	kfree(vc);
1094 }
1095 
1096 static const struct tty_port_operations vc_port_ops = {
1097 	.destruct = vc_port_destruct,
1098 };
1099 
1100 /*
1101  * Change # of rows and columns (0 means unchanged/the size of fg_console)
1102  * [this is to be used together with some user program
1103  * like resize that changes the hardware videomode]
1104  */
1105 #define VC_MAXCOL (32767)
1106 #define VC_MAXROW (32767)
1107 
1108 int vc_allocate(unsigned int currcons)	/* return 0 on success */
1109 {
1110 	struct vt_notifier_param param;
1111 	struct vc_data *vc;
1112 	int err;
1113 
1114 	WARN_CONSOLE_UNLOCKED();
1115 
1116 	if (currcons >= MAX_NR_CONSOLES)
1117 		return -ENXIO;
1118 
1119 	if (vc_cons[currcons].d)
1120 		return 0;
1121 
1122 	/* due to the granularity of kmalloc, we waste some memory here */
1123 	/* the alloc is done in two steps, to optimize the common situation
1124 	   of a 25x80 console (structsize=216, screenbuf_size=4000) */
1125 	/* although the numbers above are not valid since long ago, the
1126 	   point is still up-to-date and the comment still has its value
1127 	   even if only as a historical artifact.  --mj, July 1998 */
1128 	param.vc = vc = kzalloc(sizeof(struct vc_data), GFP_KERNEL);
1129 	if (!vc)
1130 		return -ENOMEM;
1131 
1132 	vc_cons[currcons].d = vc;
1133 	tty_port_init(&vc->port);
1134 	vc->port.ops = &vc_port_ops;
1135 	INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
1136 
1137 	visual_init(vc, currcons, 1);
1138 
1139 	if (!*vc->vc_uni_pagedir_loc)
1140 		con_set_default_unimap(vc);
1141 
1142 	err = -EINVAL;
1143 	if (vc->vc_cols > VC_MAXCOL || vc->vc_rows > VC_MAXROW ||
1144 	    vc->vc_screenbuf_size > KMALLOC_MAX_SIZE || !vc->vc_screenbuf_size)
1145 		goto err_free;
1146 	err = -ENOMEM;
1147 	vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
1148 	if (!vc->vc_screenbuf)
1149 		goto err_free;
1150 
1151 	/* If no drivers have overridden us and the user didn't pass a
1152 	   boot option, default to displaying the cursor */
1153 	if (global_cursor_default == -1)
1154 		global_cursor_default = 1;
1155 
1156 	vc_init(vc, vc->vc_rows, vc->vc_cols, 1);
1157 	vcs_make_sysfs(currcons);
1158 	atomic_notifier_call_chain(&vt_notifier_list, VT_ALLOCATE, &param);
1159 
1160 	return 0;
1161 err_free:
1162 	visual_deinit(vc);
1163 	kfree(vc);
1164 	vc_cons[currcons].d = NULL;
1165 	return err;
1166 }
1167 
1168 static inline int resize_screen(struct vc_data *vc, int width, int height,
1169 				int user)
1170 {
1171 	/* Resizes the resolution of the display adapater */
1172 	int err = 0;
1173 
1174 	if (vc->vc_sw->con_resize)
1175 		err = vc->vc_sw->con_resize(vc, width, height, user);
1176 
1177 	return err;
1178 }
1179 
1180 /**
1181  *	vc_do_resize	-	resizing method for the tty
1182  *	@tty: tty being resized
1183  *	@vc: virtual console private data
1184  *	@cols: columns
1185  *	@lines: lines
1186  *
1187  *	Resize a virtual console, clipping according to the actual constraints.
1188  *	If the caller passes a tty structure then update the termios winsize
1189  *	information and perform any necessary signal handling.
1190  *
1191  *	Caller must hold the console semaphore. Takes the termios rwsem and
1192  *	ctrl.lock of the tty IFF a tty is passed.
1193  */
1194 
1195 static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
1196 				unsigned int cols, unsigned int lines)
1197 {
1198 	unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0;
1199 	unsigned long end;
1200 	unsigned int old_rows, old_row_size, first_copied_row;
1201 	unsigned int new_cols, new_rows, new_row_size, new_screen_size;
1202 	unsigned int user;
1203 	unsigned short *oldscreen, *newscreen;
1204 	struct uni_screen *new_uniscr = NULL;
1205 
1206 	WARN_CONSOLE_UNLOCKED();
1207 
1208 	if (!vc)
1209 		return -ENXIO;
1210 
1211 	user = vc->vc_resize_user;
1212 	vc->vc_resize_user = 0;
1213 
1214 	if (cols > VC_MAXCOL || lines > VC_MAXROW)
1215 		return -EINVAL;
1216 
1217 	new_cols = (cols ? cols : vc->vc_cols);
1218 	new_rows = (lines ? lines : vc->vc_rows);
1219 	new_row_size = new_cols << 1;
1220 	new_screen_size = new_row_size * new_rows;
1221 
1222 	if (new_cols == vc->vc_cols && new_rows == vc->vc_rows) {
1223 		/*
1224 		 * This function is being called here to cover the case
1225 		 * where the userspace calls the FBIOPUT_VSCREENINFO twice,
1226 		 * passing the same fb_var_screeninfo containing the fields
1227 		 * yres/xres equal to a number non-multiple of vc_font.height
1228 		 * and yres_virtual/xres_virtual equal to number lesser than the
1229 		 * vc_font.height and yres/xres.
1230 		 * In the second call, the struct fb_var_screeninfo isn't
1231 		 * being modified by the underlying driver because of the
1232 		 * if above, and this causes the fbcon_display->vrows to become
1233 		 * negative and it eventually leads to out-of-bound
1234 		 * access by the imageblit function.
1235 		 * To give the correct values to the struct and to not have
1236 		 * to deal with possible errors from the code below, we call
1237 		 * the resize_screen here as well.
1238 		 */
1239 		return resize_screen(vc, new_cols, new_rows, user);
1240 	}
1241 
1242 	if (new_screen_size > KMALLOC_MAX_SIZE || !new_screen_size)
1243 		return -EINVAL;
1244 	newscreen = kzalloc(new_screen_size, GFP_USER);
1245 	if (!newscreen)
1246 		return -ENOMEM;
1247 
1248 	if (get_vc_uniscr(vc)) {
1249 		new_uniscr = vc_uniscr_alloc(new_cols, new_rows);
1250 		if (!new_uniscr) {
1251 			kfree(newscreen);
1252 			return -ENOMEM;
1253 		}
1254 	}
1255 
1256 	if (vc_is_sel(vc))
1257 		clear_selection();
1258 
1259 	old_rows = vc->vc_rows;
1260 	old_row_size = vc->vc_size_row;
1261 
1262 	err = resize_screen(vc, new_cols, new_rows, user);
1263 	if (err) {
1264 		kfree(newscreen);
1265 		vc_uniscr_free(new_uniscr);
1266 		return err;
1267 	}
1268 
1269 	vc->vc_rows = new_rows;
1270 	vc->vc_cols = new_cols;
1271 	vc->vc_size_row = new_row_size;
1272 	vc->vc_screenbuf_size = new_screen_size;
1273 
1274 	rlth = min(old_row_size, new_row_size);
1275 	rrem = new_row_size - rlth;
1276 	old_origin = vc->vc_origin;
1277 	new_origin = (long) newscreen;
1278 	new_scr_end = new_origin + new_screen_size;
1279 
1280 	if (vc->state.y > new_rows) {
1281 		if (old_rows - vc->state.y < new_rows) {
1282 			/*
1283 			 * Cursor near the bottom, copy contents from the
1284 			 * bottom of buffer
1285 			 */
1286 			first_copied_row = (old_rows - new_rows);
1287 		} else {
1288 			/*
1289 			 * Cursor is in no man's land, copy 1/2 screenful
1290 			 * from the top and bottom of cursor position
1291 			 */
1292 			first_copied_row = (vc->state.y - new_rows/2);
1293 		}
1294 		old_origin += first_copied_row * old_row_size;
1295 	} else
1296 		first_copied_row = 0;
1297 	end = old_origin + old_row_size * min(old_rows, new_rows);
1298 
1299 	vc_uniscr_copy_area(new_uniscr, new_cols, new_rows,
1300 			    get_vc_uniscr(vc), rlth/2, first_copied_row,
1301 			    min(old_rows, new_rows));
1302 	vc_uniscr_set(vc, new_uniscr);
1303 
1304 	update_attr(vc);
1305 
1306 	while (old_origin < end) {
1307 		scr_memcpyw((unsigned short *) new_origin,
1308 			    (unsigned short *) old_origin, rlth);
1309 		if (rrem)
1310 			scr_memsetw((void *)(new_origin + rlth),
1311 				    vc->vc_video_erase_char, rrem);
1312 		old_origin += old_row_size;
1313 		new_origin += new_row_size;
1314 	}
1315 	if (new_scr_end > new_origin)
1316 		scr_memsetw((void *)new_origin, vc->vc_video_erase_char,
1317 			    new_scr_end - new_origin);
1318 	oldscreen = vc->vc_screenbuf;
1319 	vc->vc_screenbuf = newscreen;
1320 	vc->vc_screenbuf_size = new_screen_size;
1321 	set_origin(vc);
1322 	kfree(oldscreen);
1323 
1324 	/* do part of a reset_terminal() */
1325 	vc->vc_top = 0;
1326 	vc->vc_bottom = vc->vc_rows;
1327 	gotoxy(vc, vc->state.x, vc->state.y);
1328 	save_cur(vc);
1329 
1330 	if (tty) {
1331 		/* Rewrite the requested winsize data with the actual
1332 		   resulting sizes */
1333 		struct winsize ws;
1334 		memset(&ws, 0, sizeof(ws));
1335 		ws.ws_row = vc->vc_rows;
1336 		ws.ws_col = vc->vc_cols;
1337 		ws.ws_ypixel = vc->vc_scan_lines;
1338 		tty_do_resize(tty, &ws);
1339 	}
1340 
1341 	if (con_is_visible(vc))
1342 		update_screen(vc);
1343 	vt_event_post(VT_EVENT_RESIZE, vc->vc_num, vc->vc_num);
1344 	notify_update(vc);
1345 	return err;
1346 }
1347 
1348 /**
1349  *	vc_resize		-	resize a VT
1350  *	@vc: virtual console
1351  *	@cols: columns
1352  *	@rows: rows
1353  *
1354  *	Resize a virtual console as seen from the console end of things. We
1355  *	use the common vc_do_resize methods to update the structures. The
1356  *	caller must hold the console sem to protect console internals and
1357  *	vc->port.tty
1358  */
1359 
1360 int vc_resize(struct vc_data *vc, unsigned int cols, unsigned int rows)
1361 {
1362 	return vc_do_resize(vc->port.tty, vc, cols, rows);
1363 }
1364 
1365 /**
1366  *	vt_resize		-	resize a VT
1367  *	@tty: tty to resize
1368  *	@ws: winsize attributes
1369  *
1370  *	Resize a virtual terminal. This is called by the tty layer as we
1371  *	register our own handler for resizing. The mutual helper does all
1372  *	the actual work.
1373  *
1374  *	Takes the console sem and the called methods then take the tty
1375  *	termios_rwsem and the tty ctrl.lock in that order.
1376  */
1377 static int vt_resize(struct tty_struct *tty, struct winsize *ws)
1378 {
1379 	struct vc_data *vc = tty->driver_data;
1380 	int ret;
1381 
1382 	console_lock();
1383 	ret = vc_do_resize(tty, vc, ws->ws_col, ws->ws_row);
1384 	console_unlock();
1385 	return ret;
1386 }
1387 
1388 struct vc_data *vc_deallocate(unsigned int currcons)
1389 {
1390 	struct vc_data *vc = NULL;
1391 
1392 	WARN_CONSOLE_UNLOCKED();
1393 
1394 	if (vc_cons_allocated(currcons)) {
1395 		struct vt_notifier_param param;
1396 
1397 		param.vc = vc = vc_cons[currcons].d;
1398 		atomic_notifier_call_chain(&vt_notifier_list, VT_DEALLOCATE, &param);
1399 		vcs_remove_sysfs(currcons);
1400 		visual_deinit(vc);
1401 		con_free_unimap(vc);
1402 		put_pid(vc->vt_pid);
1403 		vc_uniscr_set(vc, NULL);
1404 		kfree(vc->vc_screenbuf);
1405 		vc_cons[currcons].d = NULL;
1406 	}
1407 	return vc;
1408 }
1409 
1410 /*
1411  *	VT102 emulator
1412  */
1413 
1414 enum { EPecma = 0, EPdec, EPeq, EPgt, EPlt};
1415 
1416 #define set_kbd(vc, x)	vt_set_kbd_mode_bit((vc)->vc_num, (x))
1417 #define clr_kbd(vc, x)	vt_clr_kbd_mode_bit((vc)->vc_num, (x))
1418 #define is_kbd(vc, x)	vt_get_kbd_mode_bit((vc)->vc_num, (x))
1419 
1420 #define decarm		VC_REPEAT
1421 #define decckm		VC_CKMODE
1422 #define kbdapplic	VC_APPLIC
1423 #define lnm		VC_CRLF
1424 
1425 const unsigned char color_table[] = { 0, 4, 2, 6, 1, 5, 3, 7,
1426 				       8,12,10,14, 9,13,11,15 };
1427 
1428 /* the default colour table, for VGA+ colour systems */
1429 unsigned char default_red[] = {
1430 	0x00, 0xaa, 0x00, 0xaa, 0x00, 0xaa, 0x00, 0xaa,
1431 	0x55, 0xff, 0x55, 0xff, 0x55, 0xff, 0x55, 0xff
1432 };
1433 module_param_array(default_red, byte, NULL, S_IRUGO | S_IWUSR);
1434 
1435 unsigned char default_grn[] = {
1436 	0x00, 0x00, 0xaa, 0x55, 0x00, 0x00, 0xaa, 0xaa,
1437 	0x55, 0x55, 0xff, 0xff, 0x55, 0x55, 0xff, 0xff
1438 };
1439 module_param_array(default_grn, byte, NULL, S_IRUGO | S_IWUSR);
1440 
1441 unsigned char default_blu[] = {
1442 	0x00, 0x00, 0x00, 0x00, 0xaa, 0xaa, 0xaa, 0xaa,
1443 	0x55, 0x55, 0x55, 0x55, 0xff, 0xff, 0xff, 0xff
1444 };
1445 module_param_array(default_blu, byte, NULL, S_IRUGO | S_IWUSR);
1446 
1447 /*
1448  * gotoxy() must verify all boundaries, because the arguments
1449  * might also be negative. If the given position is out of
1450  * bounds, the cursor is placed at the nearest margin.
1451  */
1452 static void gotoxy(struct vc_data *vc, int new_x, int new_y)
1453 {
1454 	int min_y, max_y;
1455 
1456 	if (new_x < 0)
1457 		vc->state.x = 0;
1458 	else {
1459 		if (new_x >= vc->vc_cols)
1460 			vc->state.x = vc->vc_cols - 1;
1461 		else
1462 			vc->state.x = new_x;
1463 	}
1464 
1465  	if (vc->vc_decom) {
1466 		min_y = vc->vc_top;
1467 		max_y = vc->vc_bottom;
1468 	} else {
1469 		min_y = 0;
1470 		max_y = vc->vc_rows;
1471 	}
1472 	if (new_y < min_y)
1473 		vc->state.y = min_y;
1474 	else if (new_y >= max_y)
1475 		vc->state.y = max_y - 1;
1476 	else
1477 		vc->state.y = new_y;
1478 	vc->vc_pos = vc->vc_origin + vc->state.y * vc->vc_size_row +
1479 		(vc->state.x << 1);
1480 	vc->vc_need_wrap = 0;
1481 }
1482 
1483 /* for absolute user moves, when decom is set */
1484 static void gotoxay(struct vc_data *vc, int new_x, int new_y)
1485 {
1486 	gotoxy(vc, new_x, vc->vc_decom ? (vc->vc_top + new_y) : new_y);
1487 }
1488 
1489 void scrollback(struct vc_data *vc)
1490 {
1491 	scrolldelta(-(vc->vc_rows / 2));
1492 }
1493 
1494 void scrollfront(struct vc_data *vc, int lines)
1495 {
1496 	if (!lines)
1497 		lines = vc->vc_rows / 2;
1498 	scrolldelta(lines);
1499 }
1500 
1501 static void lf(struct vc_data *vc)
1502 {
1503     	/* don't scroll if above bottom of scrolling region, or
1504 	 * if below scrolling region
1505 	 */
1506 	if (vc->state.y + 1 == vc->vc_bottom)
1507 		con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_UP, 1);
1508 	else if (vc->state.y < vc->vc_rows - 1) {
1509 		vc->state.y++;
1510 		vc->vc_pos += vc->vc_size_row;
1511 	}
1512 	vc->vc_need_wrap = 0;
1513 	notify_write(vc, '\n');
1514 }
1515 
1516 static void ri(struct vc_data *vc)
1517 {
1518     	/* don't scroll if below top of scrolling region, or
1519 	 * if above scrolling region
1520 	 */
1521 	if (vc->state.y == vc->vc_top)
1522 		con_scroll(vc, vc->vc_top, vc->vc_bottom, SM_DOWN, 1);
1523 	else if (vc->state.y > 0) {
1524 		vc->state.y--;
1525 		vc->vc_pos -= vc->vc_size_row;
1526 	}
1527 	vc->vc_need_wrap = 0;
1528 }
1529 
1530 static inline void cr(struct vc_data *vc)
1531 {
1532 	vc->vc_pos -= vc->state.x << 1;
1533 	vc->vc_need_wrap = vc->state.x = 0;
1534 	notify_write(vc, '\r');
1535 }
1536 
1537 static inline void bs(struct vc_data *vc)
1538 {
1539 	if (vc->state.x) {
1540 		vc->vc_pos -= 2;
1541 		vc->state.x--;
1542 		vc->vc_need_wrap = 0;
1543 		notify_write(vc, '\b');
1544 	}
1545 }
1546 
1547 static inline void del(struct vc_data *vc)
1548 {
1549 	/* ignored */
1550 }
1551 
1552 static void csi_J(struct vc_data *vc, int vpar)
1553 {
1554 	unsigned int count;
1555 	unsigned short * start;
1556 
1557 	switch (vpar) {
1558 		case 0:	/* erase from cursor to end of display */
1559 			vc_uniscr_clear_line(vc, vc->state.x,
1560 					     vc->vc_cols - vc->state.x);
1561 			vc_uniscr_clear_lines(vc, vc->state.y + 1,
1562 					      vc->vc_rows - vc->state.y - 1);
1563 			count = (vc->vc_scr_end - vc->vc_pos) >> 1;
1564 			start = (unsigned short *)vc->vc_pos;
1565 			break;
1566 		case 1:	/* erase from start to cursor */
1567 			vc_uniscr_clear_line(vc, 0, vc->state.x + 1);
1568 			vc_uniscr_clear_lines(vc, 0, vc->state.y);
1569 			count = ((vc->vc_pos - vc->vc_origin) >> 1) + 1;
1570 			start = (unsigned short *)vc->vc_origin;
1571 			break;
1572 		case 3: /* include scrollback */
1573 			flush_scrollback(vc);
1574 			fallthrough;
1575 		case 2: /* erase whole display */
1576 			vc_uniscr_clear_lines(vc, 0, vc->vc_rows);
1577 			count = vc->vc_cols * vc->vc_rows;
1578 			start = (unsigned short *)vc->vc_origin;
1579 			break;
1580 		default:
1581 			return;
1582 	}
1583 	scr_memsetw(start, vc->vc_video_erase_char, 2 * count);
1584 	if (con_should_update(vc))
1585 		do_update_region(vc, (unsigned long) start, count);
1586 	vc->vc_need_wrap = 0;
1587 }
1588 
1589 static void csi_K(struct vc_data *vc, int vpar)
1590 {
1591 	unsigned int count;
1592 	unsigned short *start = (unsigned short *)vc->vc_pos;
1593 	int offset;
1594 
1595 	switch (vpar) {
1596 		case 0:	/* erase from cursor to end of line */
1597 			offset = 0;
1598 			count = vc->vc_cols - vc->state.x;
1599 			break;
1600 		case 1:	/* erase from start of line to cursor */
1601 			offset = -vc->state.x;
1602 			count = vc->state.x + 1;
1603 			break;
1604 		case 2: /* erase whole line */
1605 			offset = -vc->state.x;
1606 			count = vc->vc_cols;
1607 			break;
1608 		default:
1609 			return;
1610 	}
1611 	vc_uniscr_clear_line(vc, vc->state.x + offset, count);
1612 	scr_memsetw(start + offset, vc->vc_video_erase_char, 2 * count);
1613 	vc->vc_need_wrap = 0;
1614 	if (con_should_update(vc))
1615 		do_update_region(vc, (unsigned long)(start + offset), count);
1616 }
1617 
1618 /* erase the following vpar positions */
1619 static void csi_X(struct vc_data *vc, unsigned int vpar)
1620 {					  /* not vt100? */
1621 	unsigned int count;
1622 
1623 	if (!vpar)
1624 		vpar++;
1625 
1626 	count = min(vpar, vc->vc_cols - vc->state.x);
1627 
1628 	vc_uniscr_clear_line(vc, vc->state.x, count);
1629 	scr_memsetw((unsigned short *)vc->vc_pos, vc->vc_video_erase_char, 2 * count);
1630 	if (con_should_update(vc))
1631 		vc->vc_sw->con_clear(vc, vc->state.y, vc->state.x, 1, count);
1632 	vc->vc_need_wrap = 0;
1633 }
1634 
1635 static void default_attr(struct vc_data *vc)
1636 {
1637 	vc->state.intensity = VCI_NORMAL;
1638 	vc->state.italic = false;
1639 	vc->state.underline = false;
1640 	vc->state.reverse = false;
1641 	vc->state.blink = false;
1642 	vc->state.color = vc->vc_def_color;
1643 }
1644 
1645 struct rgb { u8 r; u8 g; u8 b; };
1646 
1647 static void rgb_from_256(int i, struct rgb *c)
1648 {
1649 	if (i < 8) {            /* Standard colours. */
1650 		c->r = i&1 ? 0xaa : 0x00;
1651 		c->g = i&2 ? 0xaa : 0x00;
1652 		c->b = i&4 ? 0xaa : 0x00;
1653 	} else if (i < 16) {
1654 		c->r = i&1 ? 0xff : 0x55;
1655 		c->g = i&2 ? 0xff : 0x55;
1656 		c->b = i&4 ? 0xff : 0x55;
1657 	} else if (i < 232) {   /* 6x6x6 colour cube. */
1658 		c->r = (i - 16) / 36 * 85 / 2;
1659 		c->g = (i - 16) / 6 % 6 * 85 / 2;
1660 		c->b = (i - 16) % 6 * 85 / 2;
1661 	} else                  /* Grayscale ramp. */
1662 		c->r = c->g = c->b = i * 10 - 2312;
1663 }
1664 
1665 static void rgb_foreground(struct vc_data *vc, const struct rgb *c)
1666 {
1667 	u8 hue = 0, max = max3(c->r, c->g, c->b);
1668 
1669 	if (c->r > max / 2)
1670 		hue |= 4;
1671 	if (c->g > max / 2)
1672 		hue |= 2;
1673 	if (c->b > max / 2)
1674 		hue |= 1;
1675 
1676 	if (hue == 7 && max <= 0x55) {
1677 		hue = 0;
1678 		vc->state.intensity = VCI_BOLD;
1679 	} else if (max > 0xaa)
1680 		vc->state.intensity = VCI_BOLD;
1681 	else
1682 		vc->state.intensity = VCI_NORMAL;
1683 
1684 	vc->state.color = (vc->state.color & 0xf0) | hue;
1685 }
1686 
1687 static void rgb_background(struct vc_data *vc, const struct rgb *c)
1688 {
1689 	/* For backgrounds, err on the dark side. */
1690 	vc->state.color = (vc->state.color & 0x0f)
1691 		| (c->r&0x80) >> 1 | (c->g&0x80) >> 2 | (c->b&0x80) >> 3;
1692 }
1693 
1694 /*
1695  * ITU T.416 Higher colour modes. They break the usual properties of SGR codes
1696  * and thus need to be detected and ignored by hand. That standard also
1697  * wants : rather than ; as separators but sequences containing : are currently
1698  * completely ignored by the parser.
1699  *
1700  * Subcommands 3 (CMY) and 4 (CMYK) are so insane there's no point in
1701  * supporting them.
1702  */
1703 static int vc_t416_color(struct vc_data *vc, int i,
1704 		void(*set_color)(struct vc_data *vc, const struct rgb *c))
1705 {
1706 	struct rgb c;
1707 
1708 	i++;
1709 	if (i > vc->vc_npar)
1710 		return i;
1711 
1712 	if (vc->vc_par[i] == 5 && i + 1 <= vc->vc_npar) {
1713 		/* 256 colours */
1714 		i++;
1715 		rgb_from_256(vc->vc_par[i], &c);
1716 	} else if (vc->vc_par[i] == 2 && i + 3 <= vc->vc_npar) {
1717 		/* 24 bit */
1718 		c.r = vc->vc_par[i + 1];
1719 		c.g = vc->vc_par[i + 2];
1720 		c.b = vc->vc_par[i + 3];
1721 		i += 3;
1722 	} else
1723 		return i;
1724 
1725 	set_color(vc, &c);
1726 
1727 	return i;
1728 }
1729 
1730 /* console_lock is held */
1731 static void csi_m(struct vc_data *vc)
1732 {
1733 	int i;
1734 
1735 	for (i = 0; i <= vc->vc_npar; i++)
1736 		switch (vc->vc_par[i]) {
1737 		case 0:	/* all attributes off */
1738 			default_attr(vc);
1739 			break;
1740 		case 1:
1741 			vc->state.intensity = VCI_BOLD;
1742 			break;
1743 		case 2:
1744 			vc->state.intensity = VCI_HALF_BRIGHT;
1745 			break;
1746 		case 3:
1747 			vc->state.italic = true;
1748 			break;
1749 		case 21:
1750 			/*
1751 			 * No console drivers support double underline, so
1752 			 * convert it to a single underline.
1753 			 */
1754 		case 4:
1755 			vc->state.underline = true;
1756 			break;
1757 		case 5:
1758 			vc->state.blink = true;
1759 			break;
1760 		case 7:
1761 			vc->state.reverse = true;
1762 			break;
1763 		case 10: /* ANSI X3.64-1979 (SCO-ish?)
1764 			  * Select primary font, don't display control chars if
1765 			  * defined, don't set bit 8 on output.
1766 			  */
1767 			vc->vc_translate = set_translate(vc->state.Gx_charset[vc->state.charset], vc);
1768 			vc->vc_disp_ctrl = 0;
1769 			vc->vc_toggle_meta = 0;
1770 			break;
1771 		case 11: /* ANSI X3.64-1979 (SCO-ish?)
1772 			  * Select first alternate font, lets chars < 32 be
1773 			  * displayed as ROM chars.
1774 			  */
1775 			vc->vc_translate = set_translate(IBMPC_MAP, vc);
1776 			vc->vc_disp_ctrl = 1;
1777 			vc->vc_toggle_meta = 0;
1778 			break;
1779 		case 12: /* ANSI X3.64-1979 (SCO-ish?)
1780 			  * Select second alternate font, toggle high bit
1781 			  * before displaying as ROM char.
1782 			  */
1783 			vc->vc_translate = set_translate(IBMPC_MAP, vc);
1784 			vc->vc_disp_ctrl = 1;
1785 			vc->vc_toggle_meta = 1;
1786 			break;
1787 		case 22:
1788 			vc->state.intensity = VCI_NORMAL;
1789 			break;
1790 		case 23:
1791 			vc->state.italic = false;
1792 			break;
1793 		case 24:
1794 			vc->state.underline = false;
1795 			break;
1796 		case 25:
1797 			vc->state.blink = false;
1798 			break;
1799 		case 27:
1800 			vc->state.reverse = false;
1801 			break;
1802 		case 38:
1803 			i = vc_t416_color(vc, i, rgb_foreground);
1804 			break;
1805 		case 48:
1806 			i = vc_t416_color(vc, i, rgb_background);
1807 			break;
1808 		case 39:
1809 			vc->state.color = (vc->vc_def_color & 0x0f) |
1810 				(vc->state.color & 0xf0);
1811 			break;
1812 		case 49:
1813 			vc->state.color = (vc->vc_def_color & 0xf0) |
1814 				(vc->state.color & 0x0f);
1815 			break;
1816 		default:
1817 			if (vc->vc_par[i] >= 90 && vc->vc_par[i] <= 107) {
1818 				if (vc->vc_par[i] < 100)
1819 					vc->state.intensity = VCI_BOLD;
1820 				vc->vc_par[i] -= 60;
1821 			}
1822 			if (vc->vc_par[i] >= 30 && vc->vc_par[i] <= 37)
1823 				vc->state.color = color_table[vc->vc_par[i] - 30]
1824 					| (vc->state.color & 0xf0);
1825 			else if (vc->vc_par[i] >= 40 && vc->vc_par[i] <= 47)
1826 				vc->state.color = (color_table[vc->vc_par[i] - 40] << 4)
1827 					| (vc->state.color & 0x0f);
1828 			break;
1829 		}
1830 	update_attr(vc);
1831 }
1832 
1833 static void respond_string(const char *p, size_t len, struct tty_port *port)
1834 {
1835 	tty_insert_flip_string(port, p, len);
1836 	tty_schedule_flip(port);
1837 }
1838 
1839 static void cursor_report(struct vc_data *vc, struct tty_struct *tty)
1840 {
1841 	char buf[40];
1842 	int len;
1843 
1844 	len = sprintf(buf, "\033[%d;%dR", vc->state.y +
1845 			(vc->vc_decom ? vc->vc_top + 1 : 1),
1846 			vc->state.x + 1);
1847 	respond_string(buf, len, tty->port);
1848 }
1849 
1850 static inline void status_report(struct tty_struct *tty)
1851 {
1852 	static const char teminal_ok[] = "\033[0n";
1853 
1854 	respond_string(teminal_ok, strlen(teminal_ok), tty->port);
1855 }
1856 
1857 static inline void respond_ID(struct tty_struct *tty)
1858 {
1859 	/* terminal answer to an ESC-Z or csi0c query. */
1860 	static const char vt102_id[] = "\033[?6c";
1861 
1862 	respond_string(vt102_id, strlen(vt102_id), tty->port);
1863 }
1864 
1865 void mouse_report(struct tty_struct *tty, int butt, int mrx, int mry)
1866 {
1867 	char buf[8];
1868 	int len;
1869 
1870 	len = sprintf(buf, "\033[M%c%c%c", (char)(' ' + butt),
1871 			(char)('!' + mrx), (char)('!' + mry));
1872 	respond_string(buf, len, tty->port);
1873 }
1874 
1875 /* invoked via ioctl(TIOCLINUX) and through set_selection_user */
1876 int mouse_reporting(void)
1877 {
1878 	return vc_cons[fg_console].d->vc_report_mouse;
1879 }
1880 
1881 /* console_lock is held */
1882 static void set_mode(struct vc_data *vc, int on_off)
1883 {
1884 	int i;
1885 
1886 	for (i = 0; i <= vc->vc_npar; i++)
1887 		if (vc->vc_priv == EPdec) {
1888 			switch(vc->vc_par[i]) {	/* DEC private modes set/reset */
1889 			case 1:			/* Cursor keys send ^[Ox/^[[x */
1890 				if (on_off)
1891 					set_kbd(vc, decckm);
1892 				else
1893 					clr_kbd(vc, decckm);
1894 				break;
1895 			case 3:	/* 80/132 mode switch unimplemented */
1896 #if 0
1897 				vc_resize(deccolm ? 132 : 80, vc->vc_rows);
1898 				/* this alone does not suffice; some user mode
1899 				   utility has to change the hardware regs */
1900 #endif
1901 				break;
1902 			case 5:			/* Inverted screen on/off */
1903 				if (vc->vc_decscnm != on_off) {
1904 					vc->vc_decscnm = on_off;
1905 					invert_screen(vc, 0,
1906 							vc->vc_screenbuf_size,
1907 							false);
1908 					update_attr(vc);
1909 				}
1910 				break;
1911 			case 6:			/* Origin relative/absolute */
1912 				vc->vc_decom = on_off;
1913 				gotoxay(vc, 0, 0);
1914 				break;
1915 			case 7:			/* Autowrap on/off */
1916 				vc->vc_decawm = on_off;
1917 				break;
1918 			case 8:			/* Autorepeat on/off */
1919 				if (on_off)
1920 					set_kbd(vc, decarm);
1921 				else
1922 					clr_kbd(vc, decarm);
1923 				break;
1924 			case 9:
1925 				vc->vc_report_mouse = on_off ? 1 : 0;
1926 				break;
1927 			case 25:		/* Cursor on/off */
1928 				vc->vc_deccm = on_off;
1929 				break;
1930 			case 1000:
1931 				vc->vc_report_mouse = on_off ? 2 : 0;
1932 				break;
1933 			}
1934 		} else {
1935 			switch(vc->vc_par[i]) {	/* ANSI modes set/reset */
1936 			case 3:			/* Monitor (display ctrls) */
1937 				vc->vc_disp_ctrl = on_off;
1938 				break;
1939 			case 4:			/* Insert Mode on/off */
1940 				vc->vc_decim = on_off;
1941 				break;
1942 			case 20:		/* Lf, Enter == CrLf/Lf */
1943 				if (on_off)
1944 					set_kbd(vc, lnm);
1945 				else
1946 					clr_kbd(vc, lnm);
1947 				break;
1948 			}
1949 		}
1950 }
1951 
1952 /* console_lock is held */
1953 static void setterm_command(struct vc_data *vc)
1954 {
1955 	switch (vc->vc_par[0]) {
1956 	case 1:	/* set color for underline mode */
1957 		if (vc->vc_can_do_color && vc->vc_par[1] < 16) {
1958 			vc->vc_ulcolor = color_table[vc->vc_par[1]];
1959 			if (vc->state.underline)
1960 				update_attr(vc);
1961 		}
1962 		break;
1963 	case 2:	/* set color for half intensity mode */
1964 		if (vc->vc_can_do_color && vc->vc_par[1] < 16) {
1965 			vc->vc_halfcolor = color_table[vc->vc_par[1]];
1966 			if (vc->state.intensity == VCI_HALF_BRIGHT)
1967 				update_attr(vc);
1968 		}
1969 		break;
1970 	case 8:	/* store colors as defaults */
1971 		vc->vc_def_color = vc->vc_attr;
1972 		if (vc->vc_hi_font_mask == 0x100)
1973 			vc->vc_def_color >>= 1;
1974 		default_attr(vc);
1975 		update_attr(vc);
1976 		break;
1977 	case 9:	/* set blanking interval */
1978 		blankinterval = min(vc->vc_par[1], 60U) * 60;
1979 		poke_blanked_console();
1980 		break;
1981 	case 10: /* set bell frequency in Hz */
1982 		if (vc->vc_npar >= 1)
1983 			vc->vc_bell_pitch = vc->vc_par[1];
1984 		else
1985 			vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
1986 		break;
1987 	case 11: /* set bell duration in msec */
1988 		if (vc->vc_npar >= 1)
1989 			vc->vc_bell_duration = (vc->vc_par[1] < 2000) ?
1990 				msecs_to_jiffies(vc->vc_par[1]) : 0;
1991 		else
1992 			vc->vc_bell_duration = DEFAULT_BELL_DURATION;
1993 		break;
1994 	case 12: /* bring specified console to the front */
1995 		if (vc->vc_par[1] >= 1 && vc_cons_allocated(vc->vc_par[1] - 1))
1996 			set_console(vc->vc_par[1] - 1);
1997 		break;
1998 	case 13: /* unblank the screen */
1999 		poke_blanked_console();
2000 		break;
2001 	case 14: /* set vesa powerdown interval */
2002 		vesa_off_interval = min(vc->vc_par[1], 60U) * 60 * HZ;
2003 		break;
2004 	case 15: /* activate the previous console */
2005 		set_console(last_console);
2006 		break;
2007 	case 16: /* set cursor blink duration in msec */
2008 		if (vc->vc_npar >= 1 && vc->vc_par[1] >= 50 &&
2009 				vc->vc_par[1] <= USHRT_MAX)
2010 			vc->vc_cur_blink_ms = vc->vc_par[1];
2011 		else
2012 			vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
2013 		break;
2014 	}
2015 }
2016 
2017 /* console_lock is held */
2018 static void csi_at(struct vc_data *vc, unsigned int nr)
2019 {
2020 	if (nr > vc->vc_cols - vc->state.x)
2021 		nr = vc->vc_cols - vc->state.x;
2022 	else if (!nr)
2023 		nr = 1;
2024 	insert_char(vc, nr);
2025 }
2026 
2027 /* console_lock is held */
2028 static void csi_L(struct vc_data *vc, unsigned int nr)
2029 {
2030 	if (nr > vc->vc_rows - vc->state.y)
2031 		nr = vc->vc_rows - vc->state.y;
2032 	else if (!nr)
2033 		nr = 1;
2034 	con_scroll(vc, vc->state.y, vc->vc_bottom, SM_DOWN, nr);
2035 	vc->vc_need_wrap = 0;
2036 }
2037 
2038 /* console_lock is held */
2039 static void csi_P(struct vc_data *vc, unsigned int nr)
2040 {
2041 	if (nr > vc->vc_cols - vc->state.x)
2042 		nr = vc->vc_cols - vc->state.x;
2043 	else if (!nr)
2044 		nr = 1;
2045 	delete_char(vc, nr);
2046 }
2047 
2048 /* console_lock is held */
2049 static void csi_M(struct vc_data *vc, unsigned int nr)
2050 {
2051 	if (nr > vc->vc_rows - vc->state.y)
2052 		nr = vc->vc_rows - vc->state.y;
2053 	else if (!nr)
2054 		nr=1;
2055 	con_scroll(vc, vc->state.y, vc->vc_bottom, SM_UP, nr);
2056 	vc->vc_need_wrap = 0;
2057 }
2058 
2059 /* console_lock is held (except via vc_init->reset_terminal */
2060 static void save_cur(struct vc_data *vc)
2061 {
2062 	memcpy(&vc->saved_state, &vc->state, sizeof(vc->state));
2063 }
2064 
2065 /* console_lock is held */
2066 static void restore_cur(struct vc_data *vc)
2067 {
2068 	memcpy(&vc->state, &vc->saved_state, sizeof(vc->state));
2069 
2070 	gotoxy(vc, vc->state.x, vc->state.y);
2071 	vc->vc_translate = set_translate(vc->state.Gx_charset[vc->state.charset],
2072 			vc);
2073 	update_attr(vc);
2074 	vc->vc_need_wrap = 0;
2075 }
2076 
2077 enum { ESnormal, ESesc, ESsquare, ESgetpars, ESfunckey,
2078 	EShash, ESsetG0, ESsetG1, ESpercent, EScsiignore, ESnonstd,
2079 	ESpalette, ESosc };
2080 
2081 /* console_lock is held (except via vc_init()) */
2082 static void reset_terminal(struct vc_data *vc, int do_clear)
2083 {
2084 	unsigned int i;
2085 
2086 	vc->vc_top		= 0;
2087 	vc->vc_bottom		= vc->vc_rows;
2088 	vc->vc_state		= ESnormal;
2089 	vc->vc_priv		= EPecma;
2090 	vc->vc_translate	= set_translate(LAT1_MAP, vc);
2091 	vc->state.Gx_charset[0]	= LAT1_MAP;
2092 	vc->state.Gx_charset[1]	= GRAF_MAP;
2093 	vc->state.charset	= 0;
2094 	vc->vc_need_wrap	= 0;
2095 	vc->vc_report_mouse	= 0;
2096 	vc->vc_utf              = default_utf8;
2097 	vc->vc_utf_count	= 0;
2098 
2099 	vc->vc_disp_ctrl	= 0;
2100 	vc->vc_toggle_meta	= 0;
2101 
2102 	vc->vc_decscnm		= 0;
2103 	vc->vc_decom		= 0;
2104 	vc->vc_decawm		= 1;
2105 	vc->vc_deccm		= global_cursor_default;
2106 	vc->vc_decim		= 0;
2107 
2108 	vt_reset_keyboard(vc->vc_num);
2109 
2110 	vc->vc_cursor_type = cur_default;
2111 	vc->vc_complement_mask = vc->vc_s_complement_mask;
2112 
2113 	default_attr(vc);
2114 	update_attr(vc);
2115 
2116 	bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT);
2117 	for (i = 0; i < VC_TABSTOPS_COUNT; i += 8)
2118 		set_bit(i, vc->vc_tab_stop);
2119 
2120 	vc->vc_bell_pitch = DEFAULT_BELL_PITCH;
2121 	vc->vc_bell_duration = DEFAULT_BELL_DURATION;
2122 	vc->vc_cur_blink_ms = DEFAULT_CURSOR_BLINK_MS;
2123 
2124 	gotoxy(vc, 0, 0);
2125 	save_cur(vc);
2126 	if (do_clear)
2127 	    csi_J(vc, 2);
2128 }
2129 
2130 static void vc_setGx(struct vc_data *vc, unsigned int which, int c)
2131 {
2132 	unsigned char *charset = &vc->state.Gx_charset[which];
2133 
2134 	switch (c) {
2135 	case '0':
2136 		*charset = GRAF_MAP;
2137 		break;
2138 	case 'B':
2139 		*charset = LAT1_MAP;
2140 		break;
2141 	case 'U':
2142 		*charset = IBMPC_MAP;
2143 		break;
2144 	case 'K':
2145 		*charset = USER_MAP;
2146 		break;
2147 	}
2148 
2149 	if (vc->state.charset == which)
2150 		vc->vc_translate = set_translate(*charset, vc);
2151 }
2152 
2153 /* console_lock is held */
2154 static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
2155 {
2156 	/*
2157 	 *  Control characters can be used in the _middle_
2158 	 *  of an escape sequence.
2159 	 */
2160 	if (vc->vc_state == ESosc && c>=8 && c<=13) /* ... except for OSC */
2161 		return;
2162 	switch (c) {
2163 	case 0:
2164 		return;
2165 	case 7:
2166 		if (vc->vc_state == ESosc)
2167 			vc->vc_state = ESnormal;
2168 		else if (vc->vc_bell_duration)
2169 			kd_mksound(vc->vc_bell_pitch, vc->vc_bell_duration);
2170 		return;
2171 	case 8:
2172 		bs(vc);
2173 		return;
2174 	case 9:
2175 		vc->vc_pos -= (vc->state.x << 1);
2176 
2177 		vc->state.x = find_next_bit(vc->vc_tab_stop,
2178 				min(vc->vc_cols - 1, VC_TABSTOPS_COUNT),
2179 				vc->state.x + 1);
2180 		if (vc->state.x >= VC_TABSTOPS_COUNT)
2181 			vc->state.x = vc->vc_cols - 1;
2182 
2183 		vc->vc_pos += (vc->state.x << 1);
2184 		notify_write(vc, '\t');
2185 		return;
2186 	case 10: case 11: case 12:
2187 		lf(vc);
2188 		if (!is_kbd(vc, lnm))
2189 			return;
2190 		fallthrough;
2191 	case 13:
2192 		cr(vc);
2193 		return;
2194 	case 14:
2195 		vc->state.charset = 1;
2196 		vc->vc_translate = set_translate(vc->state.Gx_charset[1], vc);
2197 		vc->vc_disp_ctrl = 1;
2198 		return;
2199 	case 15:
2200 		vc->state.charset = 0;
2201 		vc->vc_translate = set_translate(vc->state.Gx_charset[0], vc);
2202 		vc->vc_disp_ctrl = 0;
2203 		return;
2204 	case 24: case 26:
2205 		vc->vc_state = ESnormal;
2206 		return;
2207 	case 27:
2208 		vc->vc_state = ESesc;
2209 		return;
2210 	case 127:
2211 		del(vc);
2212 		return;
2213 	case 128+27:
2214 		vc->vc_state = ESsquare;
2215 		return;
2216 	}
2217 	switch(vc->vc_state) {
2218 	case ESesc:
2219 		vc->vc_state = ESnormal;
2220 		switch (c) {
2221 		case '[':
2222 			vc->vc_state = ESsquare;
2223 			return;
2224 		case ']':
2225 			vc->vc_state = ESnonstd;
2226 			return;
2227 		case '%':
2228 			vc->vc_state = ESpercent;
2229 			return;
2230 		case 'E':
2231 			cr(vc);
2232 			lf(vc);
2233 			return;
2234 		case 'M':
2235 			ri(vc);
2236 			return;
2237 		case 'D':
2238 			lf(vc);
2239 			return;
2240 		case 'H':
2241 			if (vc->state.x < VC_TABSTOPS_COUNT)
2242 				set_bit(vc->state.x, vc->vc_tab_stop);
2243 			return;
2244 		case 'Z':
2245 			respond_ID(tty);
2246 			return;
2247 		case '7':
2248 			save_cur(vc);
2249 			return;
2250 		case '8':
2251 			restore_cur(vc);
2252 			return;
2253 		case '(':
2254 			vc->vc_state = ESsetG0;
2255 			return;
2256 		case ')':
2257 			vc->vc_state = ESsetG1;
2258 			return;
2259 		case '#':
2260 			vc->vc_state = EShash;
2261 			return;
2262 		case 'c':
2263 			reset_terminal(vc, 1);
2264 			return;
2265 		case '>':  /* Numeric keypad */
2266 			clr_kbd(vc, kbdapplic);
2267 			return;
2268 		case '=':  /* Appl. keypad */
2269 			set_kbd(vc, kbdapplic);
2270 			return;
2271 		}
2272 		return;
2273 	case ESnonstd:
2274 		if (c=='P') {   /* palette escape sequence */
2275 			for (vc->vc_npar = 0; vc->vc_npar < NPAR; vc->vc_npar++)
2276 				vc->vc_par[vc->vc_npar] = 0;
2277 			vc->vc_npar = 0;
2278 			vc->vc_state = ESpalette;
2279 			return;
2280 		} else if (c=='R') {   /* reset palette */
2281 			reset_palette(vc);
2282 			vc->vc_state = ESnormal;
2283 		} else if (c>='0' && c<='9')
2284 			vc->vc_state = ESosc;
2285 		else
2286 			vc->vc_state = ESnormal;
2287 		return;
2288 	case ESpalette:
2289 		if (isxdigit(c)) {
2290 			vc->vc_par[vc->vc_npar++] = hex_to_bin(c);
2291 			if (vc->vc_npar == 7) {
2292 				int i = vc->vc_par[0] * 3, j = 1;
2293 				vc->vc_palette[i] = 16 * vc->vc_par[j++];
2294 				vc->vc_palette[i++] += vc->vc_par[j++];
2295 				vc->vc_palette[i] = 16 * vc->vc_par[j++];
2296 				vc->vc_palette[i++] += vc->vc_par[j++];
2297 				vc->vc_palette[i] = 16 * vc->vc_par[j++];
2298 				vc->vc_palette[i] += vc->vc_par[j];
2299 				set_palette(vc);
2300 				vc->vc_state = ESnormal;
2301 			}
2302 		} else
2303 			vc->vc_state = ESnormal;
2304 		return;
2305 	case ESsquare:
2306 		for (vc->vc_npar = 0; vc->vc_npar < NPAR; vc->vc_npar++)
2307 			vc->vc_par[vc->vc_npar] = 0;
2308 		vc->vc_npar = 0;
2309 		vc->vc_state = ESgetpars;
2310 		if (c == '[') { /* Function key */
2311 			vc->vc_state=ESfunckey;
2312 			return;
2313 		}
2314 		switch (c) {
2315 		case '?':
2316 			vc->vc_priv = EPdec;
2317 			return;
2318 		case '>':
2319 			vc->vc_priv = EPgt;
2320 			return;
2321 		case '=':
2322 			vc->vc_priv = EPeq;
2323 			return;
2324 		case '<':
2325 			vc->vc_priv = EPlt;
2326 			return;
2327 		}
2328 		vc->vc_priv = EPecma;
2329 		fallthrough;
2330 	case ESgetpars:
2331 		if (c == ';' && vc->vc_npar < NPAR - 1) {
2332 			vc->vc_npar++;
2333 			return;
2334 		} else if (c>='0' && c<='9') {
2335 			vc->vc_par[vc->vc_npar] *= 10;
2336 			vc->vc_par[vc->vc_npar] += c - '0';
2337 			return;
2338 		}
2339 		if (c >= 0x20 && c <= 0x3f) { /* 0x2x, 0x3a and 0x3c - 0x3f */
2340 			vc->vc_state = EScsiignore;
2341 			return;
2342 		}
2343 		vc->vc_state = ESnormal;
2344 		switch(c) {
2345 		case 'h':
2346 			if (vc->vc_priv <= EPdec)
2347 				set_mode(vc, 1);
2348 			return;
2349 		case 'l':
2350 			if (vc->vc_priv <= EPdec)
2351 				set_mode(vc, 0);
2352 			return;
2353 		case 'c':
2354 			if (vc->vc_priv == EPdec) {
2355 				if (vc->vc_par[0])
2356 					vc->vc_cursor_type =
2357 						CUR_MAKE(vc->vc_par[0],
2358 							 vc->vc_par[1],
2359 							 vc->vc_par[2]);
2360 				else
2361 					vc->vc_cursor_type = cur_default;
2362 				return;
2363 			}
2364 			break;
2365 		case 'm':
2366 			if (vc->vc_priv == EPdec) {
2367 				clear_selection();
2368 				if (vc->vc_par[0])
2369 					vc->vc_complement_mask = vc->vc_par[0] << 8 | vc->vc_par[1];
2370 				else
2371 					vc->vc_complement_mask = vc->vc_s_complement_mask;
2372 				return;
2373 			}
2374 			break;
2375 		case 'n':
2376 			if (vc->vc_priv == EPecma) {
2377 				if (vc->vc_par[0] == 5)
2378 					status_report(tty);
2379 				else if (vc->vc_par[0] == 6)
2380 					cursor_report(vc, tty);
2381 			}
2382 			return;
2383 		}
2384 		if (vc->vc_priv != EPecma) {
2385 			vc->vc_priv = EPecma;
2386 			return;
2387 		}
2388 		switch(c) {
2389 		case 'G': case '`':
2390 			if (vc->vc_par[0])
2391 				vc->vc_par[0]--;
2392 			gotoxy(vc, vc->vc_par[0], vc->state.y);
2393 			return;
2394 		case 'A':
2395 			if (!vc->vc_par[0])
2396 				vc->vc_par[0]++;
2397 			gotoxy(vc, vc->state.x, vc->state.y - vc->vc_par[0]);
2398 			return;
2399 		case 'B': case 'e':
2400 			if (!vc->vc_par[0])
2401 				vc->vc_par[0]++;
2402 			gotoxy(vc, vc->state.x, vc->state.y + vc->vc_par[0]);
2403 			return;
2404 		case 'C': case 'a':
2405 			if (!vc->vc_par[0])
2406 				vc->vc_par[0]++;
2407 			gotoxy(vc, vc->state.x + vc->vc_par[0], vc->state.y);
2408 			return;
2409 		case 'D':
2410 			if (!vc->vc_par[0])
2411 				vc->vc_par[0]++;
2412 			gotoxy(vc, vc->state.x - vc->vc_par[0], vc->state.y);
2413 			return;
2414 		case 'E':
2415 			if (!vc->vc_par[0])
2416 				vc->vc_par[0]++;
2417 			gotoxy(vc, 0, vc->state.y + vc->vc_par[0]);
2418 			return;
2419 		case 'F':
2420 			if (!vc->vc_par[0])
2421 				vc->vc_par[0]++;
2422 			gotoxy(vc, 0, vc->state.y - vc->vc_par[0]);
2423 			return;
2424 		case 'd':
2425 			if (vc->vc_par[0])
2426 				vc->vc_par[0]--;
2427 			gotoxay(vc, vc->state.x ,vc->vc_par[0]);
2428 			return;
2429 		case 'H': case 'f':
2430 			if (vc->vc_par[0])
2431 				vc->vc_par[0]--;
2432 			if (vc->vc_par[1])
2433 				vc->vc_par[1]--;
2434 			gotoxay(vc, vc->vc_par[1], vc->vc_par[0]);
2435 			return;
2436 		case 'J':
2437 			csi_J(vc, vc->vc_par[0]);
2438 			return;
2439 		case 'K':
2440 			csi_K(vc, vc->vc_par[0]);
2441 			return;
2442 		case 'L':
2443 			csi_L(vc, vc->vc_par[0]);
2444 			return;
2445 		case 'M':
2446 			csi_M(vc, vc->vc_par[0]);
2447 			return;
2448 		case 'P':
2449 			csi_P(vc, vc->vc_par[0]);
2450 			return;
2451 		case 'c':
2452 			if (!vc->vc_par[0])
2453 				respond_ID(tty);
2454 			return;
2455 		case 'g':
2456 			if (!vc->vc_par[0] && vc->state.x < VC_TABSTOPS_COUNT)
2457 				set_bit(vc->state.x, vc->vc_tab_stop);
2458 			else if (vc->vc_par[0] == 3)
2459 				bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT);
2460 			return;
2461 		case 'm':
2462 			csi_m(vc);
2463 			return;
2464 		case 'q': /* DECLL - but only 3 leds */
2465 			/* map 0,1,2,3 to 0,1,2,4 */
2466 			if (vc->vc_par[0] < 4)
2467 				vt_set_led_state(vc->vc_num,
2468 					    (vc->vc_par[0] < 3) ? vc->vc_par[0] : 4);
2469 			return;
2470 		case 'r':
2471 			if (!vc->vc_par[0])
2472 				vc->vc_par[0]++;
2473 			if (!vc->vc_par[1])
2474 				vc->vc_par[1] = vc->vc_rows;
2475 			/* Minimum allowed region is 2 lines */
2476 			if (vc->vc_par[0] < vc->vc_par[1] &&
2477 			    vc->vc_par[1] <= vc->vc_rows) {
2478 				vc->vc_top = vc->vc_par[0] - 1;
2479 				vc->vc_bottom = vc->vc_par[1];
2480 				gotoxay(vc, 0, 0);
2481 			}
2482 			return;
2483 		case 's':
2484 			save_cur(vc);
2485 			return;
2486 		case 'u':
2487 			restore_cur(vc);
2488 			return;
2489 		case 'X':
2490 			csi_X(vc, vc->vc_par[0]);
2491 			return;
2492 		case '@':
2493 			csi_at(vc, vc->vc_par[0]);
2494 			return;
2495 		case ']': /* setterm functions */
2496 			setterm_command(vc);
2497 			return;
2498 		}
2499 		return;
2500 	case EScsiignore:
2501 		if (c >= 20 && c <= 0x3f)
2502 			return;
2503 		vc->vc_state = ESnormal;
2504 		return;
2505 	case ESpercent:
2506 		vc->vc_state = ESnormal;
2507 		switch (c) {
2508 		case '@':  /* defined in ISO 2022 */
2509 			vc->vc_utf = 0;
2510 			return;
2511 		case 'G':  /* prelim official escape code */
2512 		case '8':  /* retained for compatibility */
2513 			vc->vc_utf = 1;
2514 			return;
2515 		}
2516 		return;
2517 	case ESfunckey:
2518 		vc->vc_state = ESnormal;
2519 		return;
2520 	case EShash:
2521 		vc->vc_state = ESnormal;
2522 		if (c == '8') {
2523 			/* DEC screen alignment test. kludge :-) */
2524 			vc->vc_video_erase_char =
2525 				(vc->vc_video_erase_char & 0xff00) | 'E';
2526 			csi_J(vc, 2);
2527 			vc->vc_video_erase_char =
2528 				(vc->vc_video_erase_char & 0xff00) | ' ';
2529 			do_update_region(vc, vc->vc_origin, vc->vc_screenbuf_size / 2);
2530 		}
2531 		return;
2532 	case ESsetG0:
2533 		vc_setGx(vc, 0, c);
2534 		vc->vc_state = ESnormal;
2535 		return;
2536 	case ESsetG1:
2537 		vc_setGx(vc, 1, c);
2538 		vc->vc_state = ESnormal;
2539 		return;
2540 	case ESosc:
2541 		return;
2542 	default:
2543 		vc->vc_state = ESnormal;
2544 	}
2545 }
2546 
2547 /* is_double_width() is based on the wcwidth() implementation by
2548  * Markus Kuhn -- 2007-05-26 (Unicode 5.0)
2549  * Latest version: https://www.cl.cam.ac.uk/~mgk25/ucs/wcwidth.c
2550  */
2551 struct interval {
2552 	uint32_t first;
2553 	uint32_t last;
2554 };
2555 
2556 static int ucs_cmp(const void *key, const void *elt)
2557 {
2558 	uint32_t ucs = *(uint32_t *)key;
2559 	struct interval e = *(struct interval *) elt;
2560 
2561 	if (ucs > e.last)
2562 		return 1;
2563 	else if (ucs < e.first)
2564 		return -1;
2565 	return 0;
2566 }
2567 
2568 static int is_double_width(uint32_t ucs)
2569 {
2570 	static const struct interval double_width[] = {
2571 		{ 0x1100, 0x115F }, { 0x2329, 0x232A }, { 0x2E80, 0x303E },
2572 		{ 0x3040, 0xA4CF }, { 0xAC00, 0xD7A3 }, { 0xF900, 0xFAFF },
2573 		{ 0xFE10, 0xFE19 }, { 0xFE30, 0xFE6F }, { 0xFF00, 0xFF60 },
2574 		{ 0xFFE0, 0xFFE6 }, { 0x20000, 0x2FFFD }, { 0x30000, 0x3FFFD }
2575 	};
2576 	if (ucs < double_width[0].first ||
2577 	    ucs > double_width[ARRAY_SIZE(double_width) - 1].last)
2578 		return 0;
2579 
2580 	return bsearch(&ucs, double_width, ARRAY_SIZE(double_width),
2581 			sizeof(struct interval), ucs_cmp) != NULL;
2582 }
2583 
2584 struct vc_draw_region {
2585 	unsigned long from, to;
2586 	int x;
2587 };
2588 
2589 static void con_flush(struct vc_data *vc, struct vc_draw_region *draw)
2590 {
2591 	if (draw->x < 0)
2592 		return;
2593 
2594 	vc->vc_sw->con_putcs(vc, (u16 *)draw->from,
2595 			(u16 *)draw->to - (u16 *)draw->from, vc->state.y,
2596 			draw->x);
2597 	draw->x = -1;
2598 }
2599 
2600 static inline int vc_translate_ascii(const struct vc_data *vc, int c)
2601 {
2602 	if (IS_ENABLED(CONFIG_CONSOLE_TRANSLATIONS)) {
2603 		if (vc->vc_toggle_meta)
2604 			c |= 0x80;
2605 
2606 		return vc->vc_translate[c];
2607 	}
2608 
2609 	return c;
2610 }
2611 
2612 
2613 /**
2614  * vc_sanitize_unicode -- Replace invalid Unicode code points with U+FFFD
2615  * @c: the received character, or U+FFFD for invalid sequences.
2616  */
2617 static inline int vc_sanitize_unicode(const int c)
2618 {
2619 	if ((c >= 0xd800 && c <= 0xdfff) || c == 0xfffe || c == 0xffff)
2620 		return 0xfffd;
2621 
2622 	return c;
2623 }
2624 
2625 /**
2626  * vc_translate_unicode -- Combine UTF-8 into Unicode in @vc_utf_char
2627  * @vc: virtual console
2628  * @c: character to translate
2629  * @rescan: we return true if we need more (continuation) data
2630  *
2631  * @vc_utf_char is the being-constructed unicode character.
2632  * @vc_utf_count is the number of continuation bytes still expected to arrive.
2633  * @vc_npar is the number of continuation bytes arrived so far.
2634  */
2635 static int vc_translate_unicode(struct vc_data *vc, int c, bool *rescan)
2636 {
2637 	static const u32 utf8_length_changes[] = {
2638 		0x0000007f, 0x000007ff, 0x0000ffff,
2639 		0x001fffff, 0x03ffffff, 0x7fffffff
2640 	};
2641 
2642 	/* Continuation byte received */
2643 	if ((c & 0xc0) == 0x80) {
2644 		/* Unexpected continuation byte? */
2645 		if (!vc->vc_utf_count)
2646 			return 0xfffd;
2647 
2648 		vc->vc_utf_char = (vc->vc_utf_char << 6) | (c & 0x3f);
2649 		vc->vc_npar++;
2650 		if (--vc->vc_utf_count)
2651 			goto need_more_bytes;
2652 
2653 		/* Got a whole character */
2654 		c = vc->vc_utf_char;
2655 		/* Reject overlong sequences */
2656 		if (c <= utf8_length_changes[vc->vc_npar - 1] ||
2657 				c > utf8_length_changes[vc->vc_npar])
2658 			return 0xfffd;
2659 
2660 		return vc_sanitize_unicode(c);
2661 	}
2662 
2663 	/* Single ASCII byte or first byte of a sequence received */
2664 	if (vc->vc_utf_count) {
2665 		/* Continuation byte expected */
2666 		*rescan = true;
2667 		vc->vc_utf_count = 0;
2668 		return 0xfffd;
2669 	}
2670 
2671 	/* Nothing to do if an ASCII byte was received */
2672 	if (c <= 0x7f)
2673 		return c;
2674 
2675 	/* First byte of a multibyte sequence received */
2676 	vc->vc_npar = 0;
2677 	if ((c & 0xe0) == 0xc0) {
2678 		vc->vc_utf_count = 1;
2679 		vc->vc_utf_char = (c & 0x1f);
2680 	} else if ((c & 0xf0) == 0xe0) {
2681 		vc->vc_utf_count = 2;
2682 		vc->vc_utf_char = (c & 0x0f);
2683 	} else if ((c & 0xf8) == 0xf0) {
2684 		vc->vc_utf_count = 3;
2685 		vc->vc_utf_char = (c & 0x07);
2686 	} else if ((c & 0xfc) == 0xf8) {
2687 		vc->vc_utf_count = 4;
2688 		vc->vc_utf_char = (c & 0x03);
2689 	} else if ((c & 0xfe) == 0xfc) {
2690 		vc->vc_utf_count = 5;
2691 		vc->vc_utf_char = (c & 0x01);
2692 	} else {
2693 		/* 254 and 255 are invalid */
2694 		return 0xfffd;
2695 	}
2696 
2697 need_more_bytes:
2698 	return -1;
2699 }
2700 
2701 static int vc_translate(struct vc_data *vc, int *c, bool *rescan)
2702 {
2703 	/* Do no translation at all in control states */
2704 	if (vc->vc_state != ESnormal)
2705 		return *c;
2706 
2707 	if (vc->vc_utf && !vc->vc_disp_ctrl)
2708 		return *c = vc_translate_unicode(vc, *c, rescan);
2709 
2710 	/* no utf or alternate charset mode */
2711 	return vc_translate_ascii(vc, *c);
2712 }
2713 
2714 static inline unsigned char vc_invert_attr(const struct vc_data *vc)
2715 {
2716 	if (!vc->vc_can_do_color)
2717 		return vc->vc_attr ^ 0x08;
2718 
2719 	if (vc->vc_hi_font_mask == 0x100)
2720 		return   (vc->vc_attr & 0x11) |
2721 			((vc->vc_attr & 0xe0) >> 4) |
2722 			((vc->vc_attr & 0x0e) << 4);
2723 
2724 	return   (vc->vc_attr & 0x88) |
2725 		((vc->vc_attr & 0x70) >> 4) |
2726 		((vc->vc_attr & 0x07) << 4);
2727 }
2728 
2729 static bool vc_is_control(struct vc_data *vc, int tc, int c)
2730 {
2731 	/*
2732 	 * A bitmap for codes <32. A bit of 1 indicates that the code
2733 	 * corresponding to that bit number invokes some special action (such
2734 	 * as cursor movement) and should not be displayed as a glyph unless
2735 	 * the disp_ctrl mode is explicitly enabled.
2736 	 */
2737 	static const u32 CTRL_ACTION = 0x0d00ff81;
2738 	/* Cannot be overridden by disp_ctrl */
2739 	static const u32 CTRL_ALWAYS = 0x0800f501;
2740 
2741 	if (vc->vc_state != ESnormal)
2742 		return true;
2743 
2744 	if (!tc)
2745 		return true;
2746 
2747 	/*
2748 	 * If the original code was a control character we only allow a glyph
2749 	 * to be displayed if the code is not normally used (such as for cursor
2750 	 * movement) or if the disp_ctrl mode has been explicitly enabled.
2751 	 * Certain characters (as given by the CTRL_ALWAYS bitmap) are always
2752 	 * displayed as control characters, as the console would be pretty
2753 	 * useless without them; to display an arbitrary font position use the
2754 	 * direct-to-font zone in UTF-8 mode.
2755 	 */
2756 	if (c < 32) {
2757 		if (vc->vc_disp_ctrl)
2758 			return CTRL_ALWAYS & BIT(c);
2759 		else
2760 			return vc->vc_utf || (CTRL_ACTION & BIT(c));
2761 	}
2762 
2763 	if (c == 127 && !vc->vc_disp_ctrl)
2764 		return true;
2765 
2766 	if (c == 128 + 27)
2767 		return true;
2768 
2769 	return false;
2770 }
2771 
2772 static int vc_con_write_normal(struct vc_data *vc, int tc, int c,
2773 		struct vc_draw_region *draw)
2774 {
2775 	int next_c;
2776 	unsigned char vc_attr = vc->vc_attr;
2777 	u16 himask = vc->vc_hi_font_mask, charmask = himask ? 0x1ff : 0xff;
2778 	u8 width = 1;
2779 	bool inverse = false;
2780 
2781 	if (vc->vc_utf && !vc->vc_disp_ctrl) {
2782 		if (is_double_width(c))
2783 			width = 2;
2784 	}
2785 
2786 	/* Now try to find out how to display it */
2787 	tc = conv_uni_to_pc(vc, tc);
2788 	if (tc & ~charmask) {
2789 		if (tc == -1 || tc == -2)
2790 			return -1; /* nothing to display */
2791 
2792 		/* Glyph not found */
2793 		if ((!vc->vc_utf || vc->vc_disp_ctrl || c < 128) &&
2794 				!(c & ~charmask)) {
2795 			/*
2796 			 * In legacy mode use the glyph we get by a 1:1
2797 			 * mapping.
2798 			 * This would make absolutely no sense with Unicode in
2799 			 * mind, but do this for ASCII characters since a font
2800 			 * may lack Unicode mapping info and we don't want to
2801 			 * end up with having question marks only.
2802 			 */
2803 			tc = c;
2804 		} else {
2805 			/*
2806 			 * Display U+FFFD. If it's not found, display an inverse
2807 			 * question mark.
2808 			 */
2809 			tc = conv_uni_to_pc(vc, 0xfffd);
2810 			if (tc < 0) {
2811 				inverse = true;
2812 				tc = conv_uni_to_pc(vc, '?');
2813 				if (tc < 0)
2814 					tc = '?';
2815 
2816 				vc_attr = vc_invert_attr(vc);
2817 				con_flush(vc, draw);
2818 			}
2819 		}
2820 	}
2821 
2822 	next_c = c;
2823 	while (1) {
2824 		if (vc->vc_need_wrap || vc->vc_decim)
2825 			con_flush(vc, draw);
2826 		if (vc->vc_need_wrap) {
2827 			cr(vc);
2828 			lf(vc);
2829 		}
2830 		if (vc->vc_decim)
2831 			insert_char(vc, 1);
2832 		vc_uniscr_putc(vc, next_c);
2833 
2834 		if (himask)
2835 			tc = ((tc & 0x100) ? himask : 0) |
2836 			      (tc &  0xff);
2837 		tc |= (vc_attr << 8) & ~himask;
2838 
2839 		scr_writew(tc, (u16 *)vc->vc_pos);
2840 
2841 		if (con_should_update(vc) && draw->x < 0) {
2842 			draw->x = vc->state.x;
2843 			draw->from = vc->vc_pos;
2844 		}
2845 		if (vc->state.x == vc->vc_cols - 1) {
2846 			vc->vc_need_wrap = vc->vc_decawm;
2847 			draw->to = vc->vc_pos + 2;
2848 		} else {
2849 			vc->state.x++;
2850 			draw->to = (vc->vc_pos += 2);
2851 		}
2852 
2853 		if (!--width)
2854 			break;
2855 
2856 		/* A space is printed in the second column */
2857 		tc = conv_uni_to_pc(vc, ' ');
2858 		if (tc < 0)
2859 			tc = ' ';
2860 		next_c = ' ';
2861 	}
2862 	notify_write(vc, c);
2863 
2864 	if (inverse)
2865 		con_flush(vc, draw);
2866 
2867 	return 0;
2868 }
2869 
2870 /* acquires console_lock */
2871 static int do_con_write(struct tty_struct *tty, const unsigned char *buf, int count)
2872 {
2873 	struct vc_draw_region draw = {
2874 		.x = -1,
2875 	};
2876 	int c, tc, n = 0;
2877 	unsigned int currcons;
2878 	struct vc_data *vc;
2879 	struct vt_notifier_param param;
2880 	bool rescan;
2881 
2882 	if (in_interrupt())
2883 		return count;
2884 
2885 	console_lock();
2886 	vc = tty->driver_data;
2887 	if (vc == NULL) {
2888 		pr_err("vt: argh, driver_data is NULL !\n");
2889 		console_unlock();
2890 		return 0;
2891 	}
2892 
2893 	currcons = vc->vc_num;
2894 	if (!vc_cons_allocated(currcons)) {
2895 		/* could this happen? */
2896 		pr_warn_once("con_write: tty %d not allocated\n", currcons+1);
2897 		console_unlock();
2898 		return 0;
2899 	}
2900 
2901 
2902 	/* undraw cursor first */
2903 	if (con_is_fg(vc))
2904 		hide_cursor(vc);
2905 
2906 	param.vc = vc;
2907 
2908 	while (!tty->flow.stopped && count) {
2909 		int orig = *buf;
2910 		buf++;
2911 		n++;
2912 		count--;
2913 rescan_last_byte:
2914 		c = orig;
2915 		rescan = false;
2916 
2917 		tc = vc_translate(vc, &c, &rescan);
2918 		if (tc == -1)
2919 			continue;
2920 
2921 		param.c = tc;
2922 		if (atomic_notifier_call_chain(&vt_notifier_list, VT_PREWRITE,
2923 					&param) == NOTIFY_STOP)
2924 			continue;
2925 
2926 		if (vc_is_control(vc, tc, c)) {
2927 			con_flush(vc, &draw);
2928 			do_con_trol(tty, vc, orig);
2929 			continue;
2930 		}
2931 
2932 		if (vc_con_write_normal(vc, tc, c, &draw) < 0)
2933 			continue;
2934 
2935 		if (rescan)
2936 			goto rescan_last_byte;
2937 	}
2938 	con_flush(vc, &draw);
2939 	vc_uniscr_debug_check(vc);
2940 	console_conditional_schedule();
2941 	notify_update(vc);
2942 	console_unlock();
2943 	return n;
2944 }
2945 
2946 /*
2947  * This is the console switching callback.
2948  *
2949  * Doing console switching in a process context allows
2950  * us to do the switches asynchronously (needed when we want
2951  * to switch due to a keyboard interrupt).  Synchronization
2952  * with other console code and prevention of re-entrancy is
2953  * ensured with console_lock.
2954  */
2955 static void console_callback(struct work_struct *ignored)
2956 {
2957 	console_lock();
2958 
2959 	if (want_console >= 0) {
2960 		if (want_console != fg_console &&
2961 		    vc_cons_allocated(want_console)) {
2962 			hide_cursor(vc_cons[fg_console].d);
2963 			change_console(vc_cons[want_console].d);
2964 			/* we only changed when the console had already
2965 			   been allocated - a new console is not created
2966 			   in an interrupt routine */
2967 		}
2968 		want_console = -1;
2969 	}
2970 	if (do_poke_blanked_console) { /* do not unblank for a LED change */
2971 		do_poke_blanked_console = 0;
2972 		poke_blanked_console();
2973 	}
2974 	if (scrollback_delta) {
2975 		struct vc_data *vc = vc_cons[fg_console].d;
2976 		clear_selection();
2977 		if (vc->vc_mode == KD_TEXT && vc->vc_sw->con_scrolldelta)
2978 			vc->vc_sw->con_scrolldelta(vc, scrollback_delta);
2979 		scrollback_delta = 0;
2980 	}
2981 	if (blank_timer_expired) {
2982 		do_blank_screen(0);
2983 		blank_timer_expired = 0;
2984 	}
2985 	notify_update(vc_cons[fg_console].d);
2986 
2987 	console_unlock();
2988 }
2989 
2990 int set_console(int nr)
2991 {
2992 	struct vc_data *vc = vc_cons[fg_console].d;
2993 
2994 	if (!vc_cons_allocated(nr) || vt_dont_switch ||
2995 		(vc->vt_mode.mode == VT_AUTO && vc->vc_mode == KD_GRAPHICS)) {
2996 
2997 		/*
2998 		 * Console switch will fail in console_callback() or
2999 		 * change_console() so there is no point scheduling
3000 		 * the callback
3001 		 *
3002 		 * Existing set_console() users don't check the return
3003 		 * value so this shouldn't break anything
3004 		 */
3005 		return -EINVAL;
3006 	}
3007 
3008 	want_console = nr;
3009 	schedule_console_callback();
3010 
3011 	return 0;
3012 }
3013 
3014 struct tty_driver *console_driver;
3015 
3016 #ifdef CONFIG_VT_CONSOLE
3017 
3018 /**
3019  * vt_kmsg_redirect() - Sets/gets the kernel message console
3020  * @new:	The new virtual terminal number or -1 if the console should stay
3021  * 		unchanged
3022  *
3023  * By default, the kernel messages are always printed on the current virtual
3024  * console. However, the user may modify that default with the
3025  * TIOCL_SETKMSGREDIRECT ioctl call.
3026  *
3027  * This function sets the kernel message console to be @new. It returns the old
3028  * virtual console number. The virtual terminal number 0 (both as parameter and
3029  * return value) means no redirection (i.e. always printed on the currently
3030  * active console).
3031  *
3032  * The parameter -1 means that only the current console is returned, but the
3033  * value is not modified. You may use the macro vt_get_kmsg_redirect() in that
3034  * case to make the code more understandable.
3035  *
3036  * When the kernel is compiled without CONFIG_VT_CONSOLE, this function ignores
3037  * the parameter and always returns 0.
3038  */
3039 int vt_kmsg_redirect(int new)
3040 {
3041 	static int kmsg_con;
3042 
3043 	if (new != -1)
3044 		return xchg(&kmsg_con, new);
3045 	else
3046 		return kmsg_con;
3047 }
3048 
3049 /*
3050  *	Console on virtual terminal
3051  *
3052  * The console must be locked when we get here.
3053  */
3054 
3055 static void vt_console_print(struct console *co, const char *b, unsigned count)
3056 {
3057 	struct vc_data *vc = vc_cons[fg_console].d;
3058 	unsigned char c;
3059 	static DEFINE_SPINLOCK(printing_lock);
3060 	const ushort *start;
3061 	ushort start_x, cnt;
3062 	int kmsg_console;
3063 
3064 	/* console busy or not yet initialized */
3065 	if (!printable)
3066 		return;
3067 	if (!spin_trylock(&printing_lock))
3068 		return;
3069 
3070 	kmsg_console = vt_get_kmsg_redirect();
3071 	if (kmsg_console && vc_cons_allocated(kmsg_console - 1))
3072 		vc = vc_cons[kmsg_console - 1].d;
3073 
3074 	if (!vc_cons_allocated(fg_console)) {
3075 		/* impossible */
3076 		/* printk("vt_console_print: tty %d not allocated ??\n", currcons+1); */
3077 		goto quit;
3078 	}
3079 
3080 	if (vc->vc_mode != KD_TEXT)
3081 		goto quit;
3082 
3083 	/* undraw cursor first */
3084 	if (con_is_fg(vc))
3085 		hide_cursor(vc);
3086 
3087 	start = (ushort *)vc->vc_pos;
3088 	start_x = vc->state.x;
3089 	cnt = 0;
3090 	while (count--) {
3091 		c = *b++;
3092 		if (c == 10 || c == 13 || c == 8 || vc->vc_need_wrap) {
3093 			if (cnt && con_is_visible(vc))
3094 				vc->vc_sw->con_putcs(vc, start, cnt, vc->state.y, start_x);
3095 			cnt = 0;
3096 			if (c == 8) {		/* backspace */
3097 				bs(vc);
3098 				start = (ushort *)vc->vc_pos;
3099 				start_x = vc->state.x;
3100 				continue;
3101 			}
3102 			if (c != 13)
3103 				lf(vc);
3104 			cr(vc);
3105 			start = (ushort *)vc->vc_pos;
3106 			start_x = vc->state.x;
3107 			if (c == 10 || c == 13)
3108 				continue;
3109 		}
3110 		vc_uniscr_putc(vc, c);
3111 		scr_writew((vc->vc_attr << 8) + c, (unsigned short *)vc->vc_pos);
3112 		notify_write(vc, c);
3113 		cnt++;
3114 		if (vc->state.x == vc->vc_cols - 1) {
3115 			vc->vc_need_wrap = 1;
3116 		} else {
3117 			vc->vc_pos += 2;
3118 			vc->state.x++;
3119 		}
3120 	}
3121 	if (cnt && con_is_visible(vc))
3122 		vc->vc_sw->con_putcs(vc, start, cnt, vc->state.y, start_x);
3123 	set_cursor(vc);
3124 	notify_update(vc);
3125 
3126 quit:
3127 	spin_unlock(&printing_lock);
3128 }
3129 
3130 static struct tty_driver *vt_console_device(struct console *c, int *index)
3131 {
3132 	*index = c->index ? c->index-1 : fg_console;
3133 	return console_driver;
3134 }
3135 
3136 static struct console vt_console_driver = {
3137 	.name		= "tty",
3138 	.write		= vt_console_print,
3139 	.device		= vt_console_device,
3140 	.unblank	= unblank_screen,
3141 	.flags		= CON_PRINTBUFFER,
3142 	.index		= -1,
3143 };
3144 #endif
3145 
3146 /*
3147  *	Handling of Linux-specific VC ioctls
3148  */
3149 
3150 /*
3151  * Generally a bit racy with respect to console_lock();.
3152  *
3153  * There are some functions which don't need it.
3154  *
3155  * There are some functions which can sleep for arbitrary periods
3156  * (paste_selection) but we don't need the lock there anyway.
3157  *
3158  * set_selection_user has locking, and definitely needs it
3159  */
3160 
3161 int tioclinux(struct tty_struct *tty, unsigned long arg)
3162 {
3163 	char type, data;
3164 	char __user *p = (char __user *)arg;
3165 	int lines;
3166 	int ret;
3167 
3168 	if (current->signal->tty != tty && !capable(CAP_SYS_ADMIN))
3169 		return -EPERM;
3170 	if (get_user(type, p))
3171 		return -EFAULT;
3172 	ret = 0;
3173 
3174 	switch (type)
3175 	{
3176 		case TIOCL_SETSEL:
3177 			ret = set_selection_user((struct tiocl_selection
3178 						 __user *)(p+1), tty);
3179 			break;
3180 		case TIOCL_PASTESEL:
3181 			ret = paste_selection(tty);
3182 			break;
3183 		case TIOCL_UNBLANKSCREEN:
3184 			console_lock();
3185 			unblank_screen();
3186 			console_unlock();
3187 			break;
3188 		case TIOCL_SELLOADLUT:
3189 			console_lock();
3190 			ret = sel_loadlut(p);
3191 			console_unlock();
3192 			break;
3193 		case TIOCL_GETSHIFTSTATE:
3194 
3195 	/*
3196 	 * Make it possible to react to Shift+Mousebutton.
3197 	 * Note that 'shift_state' is an undocumented
3198 	 * kernel-internal variable; programs not closely
3199 	 * related to the kernel should not use this.
3200 	 */
3201 			data = vt_get_shift_state();
3202 			ret = put_user(data, p);
3203 			break;
3204 		case TIOCL_GETMOUSEREPORTING:
3205 			console_lock();	/* May be overkill */
3206 			data = mouse_reporting();
3207 			console_unlock();
3208 			ret = put_user(data, p);
3209 			break;
3210 		case TIOCL_SETVESABLANK:
3211 			console_lock();
3212 			ret = set_vesa_blanking(p);
3213 			console_unlock();
3214 			break;
3215 		case TIOCL_GETKMSGREDIRECT:
3216 			data = vt_get_kmsg_redirect();
3217 			ret = put_user(data, p);
3218 			break;
3219 		case TIOCL_SETKMSGREDIRECT:
3220 			if (!capable(CAP_SYS_ADMIN)) {
3221 				ret = -EPERM;
3222 			} else {
3223 				if (get_user(data, p+1))
3224 					ret = -EFAULT;
3225 				else
3226 					vt_kmsg_redirect(data);
3227 			}
3228 			break;
3229 		case TIOCL_GETFGCONSOLE:
3230 			/* No locking needed as this is a transiently
3231 			   correct return anyway if the caller hasn't
3232 			   disabled switching */
3233 			ret = fg_console;
3234 			break;
3235 		case TIOCL_SCROLLCONSOLE:
3236 			if (get_user(lines, (s32 __user *)(p+4))) {
3237 				ret = -EFAULT;
3238 			} else {
3239 				/* Need the console lock here. Note that lots
3240 				   of other calls need fixing before the lock
3241 				   is actually useful ! */
3242 				console_lock();
3243 				scrollfront(vc_cons[fg_console].d, lines);
3244 				console_unlock();
3245 				ret = 0;
3246 			}
3247 			break;
3248 		case TIOCL_BLANKSCREEN:	/* until explicitly unblanked, not only poked */
3249 			console_lock();
3250 			ignore_poke = 1;
3251 			do_blank_screen(0);
3252 			console_unlock();
3253 			break;
3254 		case TIOCL_BLANKEDSCREEN:
3255 			ret = console_blanked;
3256 			break;
3257 		default:
3258 			ret = -EINVAL;
3259 			break;
3260 	}
3261 	return ret;
3262 }
3263 
3264 /*
3265  * /dev/ttyN handling
3266  */
3267 
3268 static int con_write(struct tty_struct *tty, const unsigned char *buf, int count)
3269 {
3270 	int	retval;
3271 
3272 	retval = do_con_write(tty, buf, count);
3273 	con_flush_chars(tty);
3274 
3275 	return retval;
3276 }
3277 
3278 static int con_put_char(struct tty_struct *tty, unsigned char ch)
3279 {
3280 	return do_con_write(tty, &ch, 1);
3281 }
3282 
3283 static unsigned int con_write_room(struct tty_struct *tty)
3284 {
3285 	if (tty->flow.stopped)
3286 		return 0;
3287 	return 32768;		/* No limit, really; we're not buffering */
3288 }
3289 
3290 /*
3291  * con_throttle and con_unthrottle are only used for
3292  * paste_selection(), which has to stuff in a large number of
3293  * characters...
3294  */
3295 static void con_throttle(struct tty_struct *tty)
3296 {
3297 }
3298 
3299 static void con_unthrottle(struct tty_struct *tty)
3300 {
3301 	struct vc_data *vc = tty->driver_data;
3302 
3303 	wake_up_interruptible(&vc->paste_wait);
3304 }
3305 
3306 /*
3307  * Turn the Scroll-Lock LED on when the tty is stopped
3308  */
3309 static void con_stop(struct tty_struct *tty)
3310 {
3311 	int console_num;
3312 	if (!tty)
3313 		return;
3314 	console_num = tty->index;
3315 	if (!vc_cons_allocated(console_num))
3316 		return;
3317 	vt_kbd_con_stop(console_num);
3318 }
3319 
3320 /*
3321  * Turn the Scroll-Lock LED off when the console is started
3322  */
3323 static void con_start(struct tty_struct *tty)
3324 {
3325 	int console_num;
3326 	if (!tty)
3327 		return;
3328 	console_num = tty->index;
3329 	if (!vc_cons_allocated(console_num))
3330 		return;
3331 	vt_kbd_con_start(console_num);
3332 }
3333 
3334 static void con_flush_chars(struct tty_struct *tty)
3335 {
3336 	struct vc_data *vc;
3337 
3338 	if (in_interrupt())	/* from flush_to_ldisc */
3339 		return;
3340 
3341 	/* if we race with con_close(), vt may be null */
3342 	console_lock();
3343 	vc = tty->driver_data;
3344 	if (vc)
3345 		set_cursor(vc);
3346 	console_unlock();
3347 }
3348 
3349 /*
3350  * Allocate the console screen memory.
3351  */
3352 static int con_install(struct tty_driver *driver, struct tty_struct *tty)
3353 {
3354 	unsigned int currcons = tty->index;
3355 	struct vc_data *vc;
3356 	int ret;
3357 
3358 	console_lock();
3359 	ret = vc_allocate(currcons);
3360 	if (ret)
3361 		goto unlock;
3362 
3363 	vc = vc_cons[currcons].d;
3364 
3365 	/* Still being freed */
3366 	if (vc->port.tty) {
3367 		ret = -ERESTARTSYS;
3368 		goto unlock;
3369 	}
3370 
3371 	ret = tty_port_install(&vc->port, driver, tty);
3372 	if (ret)
3373 		goto unlock;
3374 
3375 	tty->driver_data = vc;
3376 	vc->port.tty = tty;
3377 	tty_port_get(&vc->port);
3378 
3379 	if (!tty->winsize.ws_row && !tty->winsize.ws_col) {
3380 		tty->winsize.ws_row = vc_cons[currcons].d->vc_rows;
3381 		tty->winsize.ws_col = vc_cons[currcons].d->vc_cols;
3382 	}
3383 	if (vc->vc_utf)
3384 		tty->termios.c_iflag |= IUTF8;
3385 	else
3386 		tty->termios.c_iflag &= ~IUTF8;
3387 unlock:
3388 	console_unlock();
3389 	return ret;
3390 }
3391 
3392 static int con_open(struct tty_struct *tty, struct file *filp)
3393 {
3394 	/* everything done in install */
3395 	return 0;
3396 }
3397 
3398 
3399 static void con_close(struct tty_struct *tty, struct file *filp)
3400 {
3401 	/* Nothing to do - we defer to shutdown */
3402 }
3403 
3404 static void con_shutdown(struct tty_struct *tty)
3405 {
3406 	struct vc_data *vc = tty->driver_data;
3407 	BUG_ON(vc == NULL);
3408 	console_lock();
3409 	vc->port.tty = NULL;
3410 	console_unlock();
3411 }
3412 
3413 static void con_cleanup(struct tty_struct *tty)
3414 {
3415 	struct vc_data *vc = tty->driver_data;
3416 
3417 	tty_port_put(&vc->port);
3418 }
3419 
3420 static int default_color           = 7; /* white */
3421 static int default_italic_color    = 2; // green (ASCII)
3422 static int default_underline_color = 3; // cyan (ASCII)
3423 module_param_named(color, default_color, int, S_IRUGO | S_IWUSR);
3424 module_param_named(italic, default_italic_color, int, S_IRUGO | S_IWUSR);
3425 module_param_named(underline, default_underline_color, int, S_IRUGO | S_IWUSR);
3426 
3427 static void vc_init(struct vc_data *vc, unsigned int rows,
3428 		    unsigned int cols, int do_clear)
3429 {
3430 	int j, k ;
3431 
3432 	vc->vc_cols = cols;
3433 	vc->vc_rows = rows;
3434 	vc->vc_size_row = cols << 1;
3435 	vc->vc_screenbuf_size = vc->vc_rows * vc->vc_size_row;
3436 
3437 	set_origin(vc);
3438 	vc->vc_pos = vc->vc_origin;
3439 	reset_vc(vc);
3440 	for (j=k=0; j<16; j++) {
3441 		vc->vc_palette[k++] = default_red[j] ;
3442 		vc->vc_palette[k++] = default_grn[j] ;
3443 		vc->vc_palette[k++] = default_blu[j] ;
3444 	}
3445 	vc->vc_def_color       = default_color;
3446 	vc->vc_ulcolor         = default_underline_color;
3447 	vc->vc_itcolor         = default_italic_color;
3448 	vc->vc_halfcolor       = 0x08;   /* grey */
3449 	init_waitqueue_head(&vc->paste_wait);
3450 	reset_terminal(vc, do_clear);
3451 }
3452 
3453 /*
3454  * This routine initializes console interrupts, and does nothing
3455  * else. If you want the screen to clear, call tty_write with
3456  * the appropriate escape-sequence.
3457  */
3458 
3459 static int __init con_init(void)
3460 {
3461 	const char *display_desc = NULL;
3462 	struct vc_data *vc;
3463 	unsigned int currcons = 0, i;
3464 
3465 	console_lock();
3466 
3467 	if (!conswitchp)
3468 		conswitchp = &dummy_con;
3469 	display_desc = conswitchp->con_startup();
3470 	if (!display_desc) {
3471 		fg_console = 0;
3472 		console_unlock();
3473 		return 0;
3474 	}
3475 
3476 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3477 		struct con_driver *con_driver = &registered_con_driver[i];
3478 
3479 		if (con_driver->con == NULL) {
3480 			con_driver->con = conswitchp;
3481 			con_driver->desc = display_desc;
3482 			con_driver->flag = CON_DRIVER_FLAG_INIT;
3483 			con_driver->first = 0;
3484 			con_driver->last = MAX_NR_CONSOLES - 1;
3485 			break;
3486 		}
3487 	}
3488 
3489 	for (i = 0; i < MAX_NR_CONSOLES; i++)
3490 		con_driver_map[i] = conswitchp;
3491 
3492 	if (blankinterval) {
3493 		blank_state = blank_normal_wait;
3494 		mod_timer(&console_timer, jiffies + (blankinterval * HZ));
3495 	}
3496 
3497 	for (currcons = 0; currcons < MIN_NR_CONSOLES; currcons++) {
3498 		vc_cons[currcons].d = vc = kzalloc(sizeof(struct vc_data), GFP_NOWAIT);
3499 		INIT_WORK(&vc_cons[currcons].SAK_work, vc_SAK);
3500 		tty_port_init(&vc->port);
3501 		visual_init(vc, currcons, 1);
3502 		/* Assuming vc->vc_{cols,rows,screenbuf_size} are sane here. */
3503 		vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_NOWAIT);
3504 		vc_init(vc, vc->vc_rows, vc->vc_cols,
3505 			currcons || !vc->vc_sw->con_save_screen);
3506 	}
3507 	currcons = fg_console = 0;
3508 	master_display_fg = vc = vc_cons[currcons].d;
3509 	set_origin(vc);
3510 	save_screen(vc);
3511 	gotoxy(vc, vc->state.x, vc->state.y);
3512 	csi_J(vc, 0);
3513 	update_screen(vc);
3514 	pr_info("Console: %s %s %dx%d\n",
3515 		vc->vc_can_do_color ? "colour" : "mono",
3516 		display_desc, vc->vc_cols, vc->vc_rows);
3517 	printable = 1;
3518 
3519 	console_unlock();
3520 
3521 #ifdef CONFIG_VT_CONSOLE
3522 	register_console(&vt_console_driver);
3523 #endif
3524 	return 0;
3525 }
3526 console_initcall(con_init);
3527 
3528 static const struct tty_operations con_ops = {
3529 	.install = con_install,
3530 	.open = con_open,
3531 	.close = con_close,
3532 	.write = con_write,
3533 	.write_room = con_write_room,
3534 	.put_char = con_put_char,
3535 	.flush_chars = con_flush_chars,
3536 	.ioctl = vt_ioctl,
3537 #ifdef CONFIG_COMPAT
3538 	.compat_ioctl = vt_compat_ioctl,
3539 #endif
3540 	.stop = con_stop,
3541 	.start = con_start,
3542 	.throttle = con_throttle,
3543 	.unthrottle = con_unthrottle,
3544 	.resize = vt_resize,
3545 	.shutdown = con_shutdown,
3546 	.cleanup = con_cleanup,
3547 };
3548 
3549 static struct cdev vc0_cdev;
3550 
3551 static ssize_t show_tty_active(struct device *dev,
3552 				struct device_attribute *attr, char *buf)
3553 {
3554 	return sprintf(buf, "tty%d\n", fg_console + 1);
3555 }
3556 static DEVICE_ATTR(active, S_IRUGO, show_tty_active, NULL);
3557 
3558 static struct attribute *vt_dev_attrs[] = {
3559 	&dev_attr_active.attr,
3560 	NULL
3561 };
3562 
3563 ATTRIBUTE_GROUPS(vt_dev);
3564 
3565 int __init vty_init(const struct file_operations *console_fops)
3566 {
3567 	cdev_init(&vc0_cdev, console_fops);
3568 	if (cdev_add(&vc0_cdev, MKDEV(TTY_MAJOR, 0), 1) ||
3569 	    register_chrdev_region(MKDEV(TTY_MAJOR, 0), 1, "/dev/vc/0") < 0)
3570 		panic("Couldn't register /dev/tty0 driver\n");
3571 	tty0dev = device_create_with_groups(tty_class, NULL,
3572 					    MKDEV(TTY_MAJOR, 0), NULL,
3573 					    vt_dev_groups, "tty0");
3574 	if (IS_ERR(tty0dev))
3575 		tty0dev = NULL;
3576 
3577 	vcs_init();
3578 
3579 	console_driver = tty_alloc_driver(MAX_NR_CONSOLES, TTY_DRIVER_REAL_RAW |
3580 			TTY_DRIVER_RESET_TERMIOS);
3581 	if (IS_ERR(console_driver))
3582 		panic("Couldn't allocate console driver\n");
3583 
3584 	console_driver->name = "tty";
3585 	console_driver->name_base = 1;
3586 	console_driver->major = TTY_MAJOR;
3587 	console_driver->minor_start = 1;
3588 	console_driver->type = TTY_DRIVER_TYPE_CONSOLE;
3589 	console_driver->init_termios = tty_std_termios;
3590 	if (default_utf8)
3591 		console_driver->init_termios.c_iflag |= IUTF8;
3592 	tty_set_operations(console_driver, &con_ops);
3593 	if (tty_register_driver(console_driver))
3594 		panic("Couldn't register console driver\n");
3595 	kbd_init();
3596 	console_map_init();
3597 #ifdef CONFIG_MDA_CONSOLE
3598 	mda_console_init();
3599 #endif
3600 	return 0;
3601 }
3602 
3603 #ifndef VT_SINGLE_DRIVER
3604 
3605 static struct class *vtconsole_class;
3606 
3607 static int do_bind_con_driver(const struct consw *csw, int first, int last,
3608 			   int deflt)
3609 {
3610 	struct module *owner = csw->owner;
3611 	const char *desc = NULL;
3612 	struct con_driver *con_driver;
3613 	int i, j = -1, k = -1, retval = -ENODEV;
3614 
3615 	if (!try_module_get(owner))
3616 		return -ENODEV;
3617 
3618 	WARN_CONSOLE_UNLOCKED();
3619 
3620 	/* check if driver is registered */
3621 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3622 		con_driver = &registered_con_driver[i];
3623 
3624 		if (con_driver->con == csw) {
3625 			desc = con_driver->desc;
3626 			retval = 0;
3627 			break;
3628 		}
3629 	}
3630 
3631 	if (retval)
3632 		goto err;
3633 
3634 	if (!(con_driver->flag & CON_DRIVER_FLAG_INIT)) {
3635 		csw->con_startup();
3636 		con_driver->flag |= CON_DRIVER_FLAG_INIT;
3637 	}
3638 
3639 	if (deflt) {
3640 		if (conswitchp)
3641 			module_put(conswitchp->owner);
3642 
3643 		__module_get(owner);
3644 		conswitchp = csw;
3645 	}
3646 
3647 	first = max(first, con_driver->first);
3648 	last = min(last, con_driver->last);
3649 
3650 	for (i = first; i <= last; i++) {
3651 		int old_was_color;
3652 		struct vc_data *vc = vc_cons[i].d;
3653 
3654 		if (con_driver_map[i])
3655 			module_put(con_driver_map[i]->owner);
3656 		__module_get(owner);
3657 		con_driver_map[i] = csw;
3658 
3659 		if (!vc || !vc->vc_sw)
3660 			continue;
3661 
3662 		j = i;
3663 
3664 		if (con_is_visible(vc)) {
3665 			k = i;
3666 			save_screen(vc);
3667 		}
3668 
3669 		old_was_color = vc->vc_can_do_color;
3670 		vc->vc_sw->con_deinit(vc);
3671 		vc->vc_origin = (unsigned long)vc->vc_screenbuf;
3672 		visual_init(vc, i, 0);
3673 		set_origin(vc);
3674 		update_attr(vc);
3675 
3676 		/* If the console changed between mono <-> color, then
3677 		 * the attributes in the screenbuf will be wrong.  The
3678 		 * following resets all attributes to something sane.
3679 		 */
3680 		if (old_was_color != vc->vc_can_do_color)
3681 			clear_buffer_attributes(vc);
3682 	}
3683 
3684 	pr_info("Console: switching ");
3685 	if (!deflt)
3686 		pr_cont("consoles %d-%d ", first + 1, last + 1);
3687 	if (j >= 0) {
3688 		struct vc_data *vc = vc_cons[j].d;
3689 
3690 		pr_cont("to %s %s %dx%d\n",
3691 			vc->vc_can_do_color ? "colour" : "mono",
3692 			desc, vc->vc_cols, vc->vc_rows);
3693 
3694 		if (k >= 0) {
3695 			vc = vc_cons[k].d;
3696 			update_screen(vc);
3697 		}
3698 	} else {
3699 		pr_cont("to %s\n", desc);
3700 	}
3701 
3702 	retval = 0;
3703 err:
3704 	module_put(owner);
3705 	return retval;
3706 };
3707 
3708 
3709 #ifdef CONFIG_VT_HW_CONSOLE_BINDING
3710 int do_unbind_con_driver(const struct consw *csw, int first, int last, int deflt)
3711 {
3712 	struct module *owner = csw->owner;
3713 	const struct consw *defcsw = NULL;
3714 	struct con_driver *con_driver = NULL, *con_back = NULL;
3715 	int i, retval = -ENODEV;
3716 
3717 	if (!try_module_get(owner))
3718 		return -ENODEV;
3719 
3720 	WARN_CONSOLE_UNLOCKED();
3721 
3722 	/* check if driver is registered and if it is unbindable */
3723 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3724 		con_driver = &registered_con_driver[i];
3725 
3726 		if (con_driver->con == csw &&
3727 		    con_driver->flag & CON_DRIVER_FLAG_MODULE) {
3728 			retval = 0;
3729 			break;
3730 		}
3731 	}
3732 
3733 	if (retval)
3734 		goto err;
3735 
3736 	retval = -ENODEV;
3737 
3738 	/* check if backup driver exists */
3739 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3740 		con_back = &registered_con_driver[i];
3741 
3742 		if (con_back->con && con_back->con != csw) {
3743 			defcsw = con_back->con;
3744 			retval = 0;
3745 			break;
3746 		}
3747 	}
3748 
3749 	if (retval)
3750 		goto err;
3751 
3752 	if (!con_is_bound(csw))
3753 		goto err;
3754 
3755 	first = max(first, con_driver->first);
3756 	last = min(last, con_driver->last);
3757 
3758 	for (i = first; i <= last; i++) {
3759 		if (con_driver_map[i] == csw) {
3760 			module_put(csw->owner);
3761 			con_driver_map[i] = NULL;
3762 		}
3763 	}
3764 
3765 	if (!con_is_bound(defcsw)) {
3766 		const struct consw *defconsw = conswitchp;
3767 
3768 		defcsw->con_startup();
3769 		con_back->flag |= CON_DRIVER_FLAG_INIT;
3770 		/*
3771 		 * vgacon may change the default driver to point
3772 		 * to dummycon, we restore it here...
3773 		 */
3774 		conswitchp = defconsw;
3775 	}
3776 
3777 	if (!con_is_bound(csw))
3778 		con_driver->flag &= ~CON_DRIVER_FLAG_INIT;
3779 
3780 	/* ignore return value, binding should not fail */
3781 	do_bind_con_driver(defcsw, first, last, deflt);
3782 err:
3783 	module_put(owner);
3784 	return retval;
3785 
3786 }
3787 EXPORT_SYMBOL_GPL(do_unbind_con_driver);
3788 
3789 static int vt_bind(struct con_driver *con)
3790 {
3791 	const struct consw *defcsw = NULL, *csw = NULL;
3792 	int i, more = 1, first = -1, last = -1, deflt = 0;
3793 
3794  	if (!con->con || !(con->flag & CON_DRIVER_FLAG_MODULE))
3795 		goto err;
3796 
3797 	csw = con->con;
3798 
3799 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
3800 		struct con_driver *con = &registered_con_driver[i];
3801 
3802 		if (con->con && !(con->flag & CON_DRIVER_FLAG_MODULE)) {
3803 			defcsw = con->con;
3804 			break;
3805 		}
3806 	}
3807 
3808 	if (!defcsw)
3809 		goto err;
3810 
3811 	while (more) {
3812 		more = 0;
3813 
3814 		for (i = con->first; i <= con->last; i++) {
3815 			if (con_driver_map[i] == defcsw) {
3816 				if (first == -1)
3817 					first = i;
3818 				last = i;
3819 				more = 1;
3820 			} else if (first != -1)
3821 				break;
3822 		}
3823 
3824 		if (first == 0 && last == MAX_NR_CONSOLES -1)
3825 			deflt = 1;
3826 
3827 		if (first != -1)
3828 			do_bind_con_driver(csw, first, last, deflt);
3829 
3830 		first = -1;
3831 		last = -1;
3832 		deflt = 0;
3833 	}
3834 
3835 err:
3836 	return 0;
3837 }
3838 
3839 static int vt_unbind(struct con_driver *con)
3840 {
3841 	const struct consw *csw = NULL;
3842 	int i, more = 1, first = -1, last = -1, deflt = 0;
3843 	int ret;
3844 
3845  	if (!con->con || !(con->flag & CON_DRIVER_FLAG_MODULE))
3846 		goto err;
3847 
3848 	csw = con->con;
3849 
3850 	while (more) {
3851 		more = 0;
3852 
3853 		for (i = con->first; i <= con->last; i++) {
3854 			if (con_driver_map[i] == csw) {
3855 				if (first == -1)
3856 					first = i;
3857 				last = i;
3858 				more = 1;
3859 			} else if (first != -1)
3860 				break;
3861 		}
3862 
3863 		if (first == 0 && last == MAX_NR_CONSOLES -1)
3864 			deflt = 1;
3865 
3866 		if (first != -1) {
3867 			ret = do_unbind_con_driver(csw, first, last, deflt);
3868 			if (ret != 0)
3869 				return ret;
3870 		}
3871 
3872 		first = -1;
3873 		last = -1;
3874 		deflt = 0;
3875 	}
3876 
3877 err:
3878 	return 0;
3879 }
3880 #else
3881 static inline int vt_bind(struct con_driver *con)
3882 {
3883 	return 0;
3884 }
3885 static inline int vt_unbind(struct con_driver *con)
3886 {
3887 	return 0;
3888 }
3889 #endif /* CONFIG_VT_HW_CONSOLE_BINDING */
3890 
3891 static ssize_t store_bind(struct device *dev, struct device_attribute *attr,
3892 			  const char *buf, size_t count)
3893 {
3894 	struct con_driver *con = dev_get_drvdata(dev);
3895 	int bind = simple_strtoul(buf, NULL, 0);
3896 
3897 	console_lock();
3898 
3899 	if (bind)
3900 		vt_bind(con);
3901 	else
3902 		vt_unbind(con);
3903 
3904 	console_unlock();
3905 
3906 	return count;
3907 }
3908 
3909 static ssize_t show_bind(struct device *dev, struct device_attribute *attr,
3910 			 char *buf)
3911 {
3912 	struct con_driver *con = dev_get_drvdata(dev);
3913 	int bind;
3914 
3915 	console_lock();
3916 	bind = con_is_bound(con->con);
3917 	console_unlock();
3918 
3919 	return snprintf(buf, PAGE_SIZE, "%i\n", bind);
3920 }
3921 
3922 static ssize_t show_name(struct device *dev, struct device_attribute *attr,
3923 			 char *buf)
3924 {
3925 	struct con_driver *con = dev_get_drvdata(dev);
3926 
3927 	return snprintf(buf, PAGE_SIZE, "%s %s\n",
3928 			(con->flag & CON_DRIVER_FLAG_MODULE) ? "(M)" : "(S)",
3929 			 con->desc);
3930 
3931 }
3932 
3933 static DEVICE_ATTR(bind, S_IRUGO|S_IWUSR, show_bind, store_bind);
3934 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
3935 
3936 static struct attribute *con_dev_attrs[] = {
3937 	&dev_attr_bind.attr,
3938 	&dev_attr_name.attr,
3939 	NULL
3940 };
3941 
3942 ATTRIBUTE_GROUPS(con_dev);
3943 
3944 static int vtconsole_init_device(struct con_driver *con)
3945 {
3946 	con->flag |= CON_DRIVER_FLAG_ATTR;
3947 	return 0;
3948 }
3949 
3950 static void vtconsole_deinit_device(struct con_driver *con)
3951 {
3952 	con->flag &= ~CON_DRIVER_FLAG_ATTR;
3953 }
3954 
3955 /**
3956  * con_is_bound - checks if driver is bound to the console
3957  * @csw: console driver
3958  *
3959  * RETURNS: zero if unbound, nonzero if bound
3960  *
3961  * Drivers can call this and if zero, they should release
3962  * all resources allocated on con_startup()
3963  */
3964 int con_is_bound(const struct consw *csw)
3965 {
3966 	int i, bound = 0;
3967 
3968 	WARN_CONSOLE_UNLOCKED();
3969 
3970 	for (i = 0; i < MAX_NR_CONSOLES; i++) {
3971 		if (con_driver_map[i] == csw) {
3972 			bound = 1;
3973 			break;
3974 		}
3975 	}
3976 
3977 	return bound;
3978 }
3979 EXPORT_SYMBOL(con_is_bound);
3980 
3981 /**
3982  * con_is_visible - checks whether the current console is visible
3983  * @vc: virtual console
3984  *
3985  * RETURNS: zero if not visible, nonzero if visible
3986  */
3987 bool con_is_visible(const struct vc_data *vc)
3988 {
3989 	WARN_CONSOLE_UNLOCKED();
3990 
3991 	return *vc->vc_display_fg == vc;
3992 }
3993 EXPORT_SYMBOL(con_is_visible);
3994 
3995 /**
3996  * con_debug_enter - prepare the console for the kernel debugger
3997  * @vc: virtual console
3998  *
3999  * Called when the console is taken over by the kernel debugger, this
4000  * function needs to save the current console state, then put the console
4001  * into a state suitable for the kernel debugger.
4002  *
4003  * RETURNS:
4004  * Zero on success, nonzero if a failure occurred when trying to prepare
4005  * the console for the debugger.
4006  */
4007 int con_debug_enter(struct vc_data *vc)
4008 {
4009 	int ret = 0;
4010 
4011 	saved_fg_console = fg_console;
4012 	saved_last_console = last_console;
4013 	saved_want_console = want_console;
4014 	saved_vc_mode = vc->vc_mode;
4015 	saved_console_blanked = console_blanked;
4016 	vc->vc_mode = KD_TEXT;
4017 	console_blanked = 0;
4018 	if (vc->vc_sw->con_debug_enter)
4019 		ret = vc->vc_sw->con_debug_enter(vc);
4020 #ifdef CONFIG_KGDB_KDB
4021 	/* Set the initial LINES variable if it is not already set */
4022 	if (vc->vc_rows < 999) {
4023 		int linecount;
4024 		char lns[4];
4025 		const char *setargs[3] = {
4026 			"set",
4027 			"LINES",
4028 			lns,
4029 		};
4030 		if (kdbgetintenv(setargs[0], &linecount)) {
4031 			snprintf(lns, 4, "%i", vc->vc_rows);
4032 			kdb_set(2, setargs);
4033 		}
4034 	}
4035 	if (vc->vc_cols < 999) {
4036 		int colcount;
4037 		char cols[4];
4038 		const char *setargs[3] = {
4039 			"set",
4040 			"COLUMNS",
4041 			cols,
4042 		};
4043 		if (kdbgetintenv(setargs[0], &colcount)) {
4044 			snprintf(cols, 4, "%i", vc->vc_cols);
4045 			kdb_set(2, setargs);
4046 		}
4047 	}
4048 #endif /* CONFIG_KGDB_KDB */
4049 	return ret;
4050 }
4051 EXPORT_SYMBOL_GPL(con_debug_enter);
4052 
4053 /**
4054  * con_debug_leave - restore console state
4055  *
4056  * Restore the console state to what it was before the kernel debugger
4057  * was invoked.
4058  *
4059  * RETURNS:
4060  * Zero on success, nonzero if a failure occurred when trying to restore
4061  * the console.
4062  */
4063 int con_debug_leave(void)
4064 {
4065 	struct vc_data *vc;
4066 	int ret = 0;
4067 
4068 	fg_console = saved_fg_console;
4069 	last_console = saved_last_console;
4070 	want_console = saved_want_console;
4071 	console_blanked = saved_console_blanked;
4072 	vc_cons[fg_console].d->vc_mode = saved_vc_mode;
4073 
4074 	vc = vc_cons[fg_console].d;
4075 	if (vc->vc_sw->con_debug_leave)
4076 		ret = vc->vc_sw->con_debug_leave(vc);
4077 	return ret;
4078 }
4079 EXPORT_SYMBOL_GPL(con_debug_leave);
4080 
4081 static int do_register_con_driver(const struct consw *csw, int first, int last)
4082 {
4083 	struct module *owner = csw->owner;
4084 	struct con_driver *con_driver;
4085 	const char *desc;
4086 	int i, retval;
4087 
4088 	WARN_CONSOLE_UNLOCKED();
4089 
4090 	if (!try_module_get(owner))
4091 		return -ENODEV;
4092 
4093 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4094 		con_driver = &registered_con_driver[i];
4095 
4096 		/* already registered */
4097 		if (con_driver->con == csw) {
4098 			retval = -EBUSY;
4099 			goto err;
4100 		}
4101 	}
4102 
4103 	desc = csw->con_startup();
4104 	if (!desc) {
4105 		retval = -ENODEV;
4106 		goto err;
4107 	}
4108 
4109 	retval = -EINVAL;
4110 
4111 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4112 		con_driver = &registered_con_driver[i];
4113 
4114 		if (con_driver->con == NULL &&
4115 		    !(con_driver->flag & CON_DRIVER_FLAG_ZOMBIE)) {
4116 			con_driver->con = csw;
4117 			con_driver->desc = desc;
4118 			con_driver->node = i;
4119 			con_driver->flag = CON_DRIVER_FLAG_MODULE |
4120 			                   CON_DRIVER_FLAG_INIT;
4121 			con_driver->first = first;
4122 			con_driver->last = last;
4123 			retval = 0;
4124 			break;
4125 		}
4126 	}
4127 
4128 	if (retval)
4129 		goto err;
4130 
4131 	con_driver->dev =
4132 		device_create_with_groups(vtconsole_class, NULL,
4133 					  MKDEV(0, con_driver->node),
4134 					  con_driver, con_dev_groups,
4135 					  "vtcon%i", con_driver->node);
4136 	if (IS_ERR(con_driver->dev)) {
4137 		pr_warn("Unable to create device for %s; errno = %ld\n",
4138 			con_driver->desc, PTR_ERR(con_driver->dev));
4139 		con_driver->dev = NULL;
4140 	} else {
4141 		vtconsole_init_device(con_driver);
4142 	}
4143 
4144 err:
4145 	module_put(owner);
4146 	return retval;
4147 }
4148 
4149 
4150 /**
4151  * do_unregister_con_driver - unregister console driver from console layer
4152  * @csw: console driver
4153  *
4154  * DESCRIPTION: All drivers that registers to the console layer must
4155  * call this function upon exit, or if the console driver is in a state
4156  * where it won't be able to handle console services, such as the
4157  * framebuffer console without loaded framebuffer drivers.
4158  *
4159  * The driver must unbind first prior to unregistration.
4160  */
4161 int do_unregister_con_driver(const struct consw *csw)
4162 {
4163 	int i;
4164 
4165 	/* cannot unregister a bound driver */
4166 	if (con_is_bound(csw))
4167 		return -EBUSY;
4168 
4169 	if (csw == conswitchp)
4170 		return -EINVAL;
4171 
4172 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4173 		struct con_driver *con_driver = &registered_con_driver[i];
4174 
4175 		if (con_driver->con == csw) {
4176 			/*
4177 			 * Defer the removal of the sysfs entries since that
4178 			 * will acquire the kernfs s_active lock and we can't
4179 			 * acquire this lock while holding the console lock:
4180 			 * the unbind sysfs entry imposes already the opposite
4181 			 * order. Reset con already here to prevent any later
4182 			 * lookup to succeed and mark this slot as zombie, so
4183 			 * it won't get reused until we complete the removal
4184 			 * in the deferred work.
4185 			 */
4186 			con_driver->con = NULL;
4187 			con_driver->flag = CON_DRIVER_FLAG_ZOMBIE;
4188 			schedule_work(&con_driver_unregister_work);
4189 
4190 			return 0;
4191 		}
4192 	}
4193 
4194 	return -ENODEV;
4195 }
4196 EXPORT_SYMBOL_GPL(do_unregister_con_driver);
4197 
4198 static void con_driver_unregister_callback(struct work_struct *ignored)
4199 {
4200 	int i;
4201 
4202 	console_lock();
4203 
4204 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4205 		struct con_driver *con_driver = &registered_con_driver[i];
4206 
4207 		if (!(con_driver->flag & CON_DRIVER_FLAG_ZOMBIE))
4208 			continue;
4209 
4210 		console_unlock();
4211 
4212 		vtconsole_deinit_device(con_driver);
4213 		device_destroy(vtconsole_class, MKDEV(0, con_driver->node));
4214 
4215 		console_lock();
4216 
4217 		if (WARN_ON_ONCE(con_driver->con))
4218 			con_driver->con = NULL;
4219 		con_driver->desc = NULL;
4220 		con_driver->dev = NULL;
4221 		con_driver->node = 0;
4222 		WARN_ON_ONCE(con_driver->flag != CON_DRIVER_FLAG_ZOMBIE);
4223 		con_driver->flag = 0;
4224 		con_driver->first = 0;
4225 		con_driver->last = 0;
4226 	}
4227 
4228 	console_unlock();
4229 }
4230 
4231 /*
4232  *	If we support more console drivers, this function is used
4233  *	when a driver wants to take over some existing consoles
4234  *	and become default driver for newly opened ones.
4235  *
4236  *	do_take_over_console is basically a register followed by bind
4237  */
4238 int do_take_over_console(const struct consw *csw, int first, int last, int deflt)
4239 {
4240 	int err;
4241 
4242 	err = do_register_con_driver(csw, first, last);
4243 	/*
4244 	 * If we get an busy error we still want to bind the console driver
4245 	 * and return success, as we may have unbound the console driver
4246 	 * but not unregistered it.
4247 	 */
4248 	if (err == -EBUSY)
4249 		err = 0;
4250 	if (!err)
4251 		do_bind_con_driver(csw, first, last, deflt);
4252 
4253 	return err;
4254 }
4255 EXPORT_SYMBOL_GPL(do_take_over_console);
4256 
4257 
4258 /*
4259  * give_up_console is a wrapper to unregister_con_driver. It will only
4260  * work if driver is fully unbound.
4261  */
4262 void give_up_console(const struct consw *csw)
4263 {
4264 	console_lock();
4265 	do_unregister_con_driver(csw);
4266 	console_unlock();
4267 }
4268 
4269 static int __init vtconsole_class_init(void)
4270 {
4271 	int i;
4272 
4273 	vtconsole_class = class_create(THIS_MODULE, "vtconsole");
4274 	if (IS_ERR(vtconsole_class)) {
4275 		pr_warn("Unable to create vt console class; errno = %ld\n",
4276 			PTR_ERR(vtconsole_class));
4277 		vtconsole_class = NULL;
4278 	}
4279 
4280 	/* Add system drivers to sysfs */
4281 	for (i = 0; i < MAX_NR_CON_DRIVER; i++) {
4282 		struct con_driver *con = &registered_con_driver[i];
4283 
4284 		if (con->con && !con->dev) {
4285 			con->dev =
4286 				device_create_with_groups(vtconsole_class, NULL,
4287 							  MKDEV(0, con->node),
4288 							  con, con_dev_groups,
4289 							  "vtcon%i", con->node);
4290 
4291 			if (IS_ERR(con->dev)) {
4292 				pr_warn("Unable to create device for %s; errno = %ld\n",
4293 					con->desc, PTR_ERR(con->dev));
4294 				con->dev = NULL;
4295 			} else {
4296 				vtconsole_init_device(con);
4297 			}
4298 		}
4299 	}
4300 
4301 	return 0;
4302 }
4303 postcore_initcall(vtconsole_class_init);
4304 
4305 #endif
4306 
4307 /*
4308  *	Screen blanking
4309  */
4310 
4311 static int set_vesa_blanking(char __user *p)
4312 {
4313 	unsigned int mode;
4314 
4315 	if (get_user(mode, p + 1))
4316 		return -EFAULT;
4317 
4318 	vesa_blank_mode = (mode < 4) ? mode : 0;
4319 	return 0;
4320 }
4321 
4322 void do_blank_screen(int entering_gfx)
4323 {
4324 	struct vc_data *vc = vc_cons[fg_console].d;
4325 	int i;
4326 
4327 	might_sleep();
4328 
4329 	WARN_CONSOLE_UNLOCKED();
4330 
4331 	if (console_blanked) {
4332 		if (blank_state == blank_vesa_wait) {
4333 			blank_state = blank_off;
4334 			vc->vc_sw->con_blank(vc, vesa_blank_mode + 1, 0);
4335 		}
4336 		return;
4337 	}
4338 
4339 	/* entering graphics mode? */
4340 	if (entering_gfx) {
4341 		hide_cursor(vc);
4342 		save_screen(vc);
4343 		vc->vc_sw->con_blank(vc, -1, 1);
4344 		console_blanked = fg_console + 1;
4345 		blank_state = blank_off;
4346 		set_origin(vc);
4347 		return;
4348 	}
4349 
4350 	blank_state = blank_off;
4351 
4352 	/* don't blank graphics */
4353 	if (vc->vc_mode != KD_TEXT) {
4354 		console_blanked = fg_console + 1;
4355 		return;
4356 	}
4357 
4358 	hide_cursor(vc);
4359 	del_timer_sync(&console_timer);
4360 	blank_timer_expired = 0;
4361 
4362 	save_screen(vc);
4363 	/* In case we need to reset origin, blanking hook returns 1 */
4364 	i = vc->vc_sw->con_blank(vc, vesa_off_interval ? 1 : (vesa_blank_mode + 1), 0);
4365 	console_blanked = fg_console + 1;
4366 	if (i)
4367 		set_origin(vc);
4368 
4369 	if (console_blank_hook && console_blank_hook(1))
4370 		return;
4371 
4372 	if (vesa_off_interval && vesa_blank_mode) {
4373 		blank_state = blank_vesa_wait;
4374 		mod_timer(&console_timer, jiffies + vesa_off_interval);
4375 	}
4376 	vt_event_post(VT_EVENT_BLANK, vc->vc_num, vc->vc_num);
4377 }
4378 EXPORT_SYMBOL(do_blank_screen);
4379 
4380 /*
4381  * Called by timer as well as from vt_console_driver
4382  */
4383 void do_unblank_screen(int leaving_gfx)
4384 {
4385 	struct vc_data *vc;
4386 
4387 	/* This should now always be called from a "sane" (read: can schedule)
4388 	 * context for the sake of the low level drivers, except in the special
4389 	 * case of oops_in_progress
4390 	 */
4391 	if (!oops_in_progress)
4392 		might_sleep();
4393 
4394 	WARN_CONSOLE_UNLOCKED();
4395 
4396 	ignore_poke = 0;
4397 	if (!console_blanked)
4398 		return;
4399 	if (!vc_cons_allocated(fg_console)) {
4400 		/* impossible */
4401 		pr_warn("unblank_screen: tty %d not allocated ??\n",
4402 			fg_console + 1);
4403 		return;
4404 	}
4405 	vc = vc_cons[fg_console].d;
4406 	if (vc->vc_mode != KD_TEXT)
4407 		return; /* but leave console_blanked != 0 */
4408 
4409 	if (blankinterval) {
4410 		mod_timer(&console_timer, jiffies + (blankinterval * HZ));
4411 		blank_state = blank_normal_wait;
4412 	}
4413 
4414 	console_blanked = 0;
4415 	if (vc->vc_sw->con_blank(vc, 0, leaving_gfx))
4416 		/* Low-level driver cannot restore -> do it ourselves */
4417 		update_screen(vc);
4418 	if (console_blank_hook)
4419 		console_blank_hook(0);
4420 	set_palette(vc);
4421 	set_cursor(vc);
4422 	vt_event_post(VT_EVENT_UNBLANK, vc->vc_num, vc->vc_num);
4423 }
4424 EXPORT_SYMBOL(do_unblank_screen);
4425 
4426 /*
4427  * This is called by the outside world to cause a forced unblank, mostly for
4428  * oopses. Currently, I just call do_unblank_screen(0), but we could eventually
4429  * call it with 1 as an argument and so force a mode restore... that may kill
4430  * X or at least garbage the screen but would also make the Oops visible...
4431  */
4432 void unblank_screen(void)
4433 {
4434 	do_unblank_screen(0);
4435 }
4436 
4437 /*
4438  * We defer the timer blanking to work queue so it can take the console mutex
4439  * (console operations can still happen at irq time, but only from printk which
4440  * has the console mutex. Not perfect yet, but better than no locking
4441  */
4442 static void blank_screen_t(struct timer_list *unused)
4443 {
4444 	blank_timer_expired = 1;
4445 	schedule_work(&console_work);
4446 }
4447 
4448 void poke_blanked_console(void)
4449 {
4450 	WARN_CONSOLE_UNLOCKED();
4451 
4452 	/* Add this so we quickly catch whoever might call us in a non
4453 	 * safe context. Nowadays, unblank_screen() isn't to be called in
4454 	 * atomic contexts and is allowed to schedule (with the special case
4455 	 * of oops_in_progress, but that isn't of any concern for this
4456 	 * function. --BenH.
4457 	 */
4458 	might_sleep();
4459 
4460 	/* This isn't perfectly race free, but a race here would be mostly harmless,
4461 	 * at worst, we'll do a spurious blank and it's unlikely
4462 	 */
4463 	del_timer(&console_timer);
4464 	blank_timer_expired = 0;
4465 
4466 	if (ignore_poke || !vc_cons[fg_console].d || vc_cons[fg_console].d->vc_mode == KD_GRAPHICS)
4467 		return;
4468 	if (console_blanked)
4469 		unblank_screen();
4470 	else if (blankinterval) {
4471 		mod_timer(&console_timer, jiffies + (blankinterval * HZ));
4472 		blank_state = blank_normal_wait;
4473 	}
4474 }
4475 
4476 /*
4477  *	Palettes
4478  */
4479 
4480 static void set_palette(struct vc_data *vc)
4481 {
4482 	WARN_CONSOLE_UNLOCKED();
4483 
4484 	if (vc->vc_mode != KD_GRAPHICS && vc->vc_sw->con_set_palette)
4485 		vc->vc_sw->con_set_palette(vc, color_table);
4486 }
4487 
4488 /*
4489  * Load palette into the DAC registers. arg points to a colour
4490  * map, 3 bytes per colour, 16 colours, range from 0 to 255.
4491  */
4492 
4493 int con_set_cmap(unsigned char __user *arg)
4494 {
4495 	int i, j, k;
4496 	unsigned char colormap[3*16];
4497 
4498 	if (copy_from_user(colormap, arg, sizeof(colormap)))
4499 		return -EFAULT;
4500 
4501 	console_lock();
4502 	for (i = k = 0; i < 16; i++) {
4503 		default_red[i] = colormap[k++];
4504 		default_grn[i] = colormap[k++];
4505 		default_blu[i] = colormap[k++];
4506 	}
4507 	for (i = 0; i < MAX_NR_CONSOLES; i++) {
4508 		if (!vc_cons_allocated(i))
4509 			continue;
4510 		for (j = k = 0; j < 16; j++) {
4511 			vc_cons[i].d->vc_palette[k++] = default_red[j];
4512 			vc_cons[i].d->vc_palette[k++] = default_grn[j];
4513 			vc_cons[i].d->vc_palette[k++] = default_blu[j];
4514 		}
4515 		set_palette(vc_cons[i].d);
4516 	}
4517 	console_unlock();
4518 
4519 	return 0;
4520 }
4521 
4522 int con_get_cmap(unsigned char __user *arg)
4523 {
4524 	int i, k;
4525 	unsigned char colormap[3*16];
4526 
4527 	console_lock();
4528 	for (i = k = 0; i < 16; i++) {
4529 		colormap[k++] = default_red[i];
4530 		colormap[k++] = default_grn[i];
4531 		colormap[k++] = default_blu[i];
4532 	}
4533 	console_unlock();
4534 
4535 	if (copy_to_user(arg, colormap, sizeof(colormap)))
4536 		return -EFAULT;
4537 
4538 	return 0;
4539 }
4540 
4541 void reset_palette(struct vc_data *vc)
4542 {
4543 	int j, k;
4544 	for (j=k=0; j<16; j++) {
4545 		vc->vc_palette[k++] = default_red[j];
4546 		vc->vc_palette[k++] = default_grn[j];
4547 		vc->vc_palette[k++] = default_blu[j];
4548 	}
4549 	set_palette(vc);
4550 }
4551 
4552 /*
4553  *  Font switching
4554  *
4555  *  Currently we only support fonts up to 32 pixels wide, at a maximum height
4556  *  of 32 pixels. Userspace fontdata is stored with 32 bytes (shorts/ints,
4557  *  depending on width) reserved for each character which is kinda wasty, but
4558  *  this is done in order to maintain compatibility with the EGA/VGA fonts. It
4559  *  is up to the actual low-level console-driver convert data into its favorite
4560  *  format (maybe we should add a `fontoffset' field to the `display'
4561  *  structure so we won't have to convert the fontdata all the time.
4562  *  /Jes
4563  */
4564 
4565 #define max_font_size 65536
4566 
4567 static int con_font_get(struct vc_data *vc, struct console_font_op *op)
4568 {
4569 	struct console_font font;
4570 	int rc = -EINVAL;
4571 	int c;
4572 
4573 	if (op->data) {
4574 		font.data = kmalloc(max_font_size, GFP_KERNEL);
4575 		if (!font.data)
4576 			return -ENOMEM;
4577 	} else
4578 		font.data = NULL;
4579 
4580 	console_lock();
4581 	if (vc->vc_mode != KD_TEXT)
4582 		rc = -EINVAL;
4583 	else if (vc->vc_sw->con_font_get)
4584 		rc = vc->vc_sw->con_font_get(vc, &font);
4585 	else
4586 		rc = -ENOSYS;
4587 	console_unlock();
4588 
4589 	if (rc)
4590 		goto out;
4591 
4592 	c = (font.width+7)/8 * 32 * font.charcount;
4593 
4594 	if (op->data && font.charcount > op->charcount)
4595 		rc = -ENOSPC;
4596 	if (font.width > op->width || font.height > op->height)
4597 		rc = -ENOSPC;
4598 	if (rc)
4599 		goto out;
4600 
4601 	op->height = font.height;
4602 	op->width = font.width;
4603 	op->charcount = font.charcount;
4604 
4605 	if (op->data && copy_to_user(op->data, font.data, c))
4606 		rc = -EFAULT;
4607 
4608 out:
4609 	kfree(font.data);
4610 	return rc;
4611 }
4612 
4613 static int con_font_set(struct vc_data *vc, struct console_font_op *op)
4614 {
4615 	struct console_font font;
4616 	int rc = -EINVAL;
4617 	int size;
4618 
4619 	if (vc->vc_mode != KD_TEXT)
4620 		return -EINVAL;
4621 	if (!op->data)
4622 		return -EINVAL;
4623 	if (op->charcount > 512)
4624 		return -EINVAL;
4625 	if (op->width <= 0 || op->width > 32 || !op->height || op->height > 32)
4626 		return -EINVAL;
4627 	size = (op->width+7)/8 * 32 * op->charcount;
4628 	if (size > max_font_size)
4629 		return -ENOSPC;
4630 
4631 	font.data = memdup_user(op->data, size);
4632 	if (IS_ERR(font.data))
4633 		return PTR_ERR(font.data);
4634 
4635 	font.charcount = op->charcount;
4636 	font.width = op->width;
4637 	font.height = op->height;
4638 
4639 	console_lock();
4640 	if (vc->vc_mode != KD_TEXT)
4641 		rc = -EINVAL;
4642 	else if (vc->vc_sw->con_font_set)
4643 		rc = vc->vc_sw->con_font_set(vc, &font, op->flags);
4644 	else
4645 		rc = -ENOSYS;
4646 	console_unlock();
4647 	kfree(font.data);
4648 	return rc;
4649 }
4650 
4651 static int con_font_default(struct vc_data *vc, struct console_font_op *op)
4652 {
4653 	struct console_font font = {.width = op->width, .height = op->height};
4654 	char name[MAX_FONT_NAME];
4655 	char *s = name;
4656 	int rc;
4657 
4658 
4659 	if (!op->data)
4660 		s = NULL;
4661 	else if (strncpy_from_user(name, op->data, MAX_FONT_NAME - 1) < 0)
4662 		return -EFAULT;
4663 	else
4664 		name[MAX_FONT_NAME - 1] = 0;
4665 
4666 	console_lock();
4667 	if (vc->vc_mode != KD_TEXT) {
4668 		console_unlock();
4669 		return -EINVAL;
4670 	}
4671 	if (vc->vc_sw->con_font_default)
4672 		rc = vc->vc_sw->con_font_default(vc, &font, s);
4673 	else
4674 		rc = -ENOSYS;
4675 	console_unlock();
4676 	if (!rc) {
4677 		op->width = font.width;
4678 		op->height = font.height;
4679 	}
4680 	return rc;
4681 }
4682 
4683 int con_font_op(struct vc_data *vc, struct console_font_op *op)
4684 {
4685 	switch (op->op) {
4686 	case KD_FONT_OP_SET:
4687 		return con_font_set(vc, op);
4688 	case KD_FONT_OP_GET:
4689 		return con_font_get(vc, op);
4690 	case KD_FONT_OP_SET_DEFAULT:
4691 		return con_font_default(vc, op);
4692 	case KD_FONT_OP_COPY:
4693 		/* was buggy and never really used */
4694 		return -EINVAL;
4695 	}
4696 	return -ENOSYS;
4697 }
4698 
4699 /*
4700  *	Interface exported to selection and vcs.
4701  */
4702 
4703 /* used by selection */
4704 u16 screen_glyph(const struct vc_data *vc, int offset)
4705 {
4706 	u16 w = scr_readw(screenpos(vc, offset, true));
4707 	u16 c = w & 0xff;
4708 
4709 	if (w & vc->vc_hi_font_mask)
4710 		c |= 0x100;
4711 	return c;
4712 }
4713 EXPORT_SYMBOL_GPL(screen_glyph);
4714 
4715 u32 screen_glyph_unicode(const struct vc_data *vc, int n)
4716 {
4717 	struct uni_screen *uniscr = get_vc_uniscr(vc);
4718 
4719 	if (uniscr)
4720 		return uniscr->lines[n / vc->vc_cols][n % vc->vc_cols];
4721 	return inverse_translate(vc, screen_glyph(vc, n * 2), 1);
4722 }
4723 EXPORT_SYMBOL_GPL(screen_glyph_unicode);
4724 
4725 /* used by vcs - note the word offset */
4726 unsigned short *screen_pos(const struct vc_data *vc, int w_offset, bool viewed)
4727 {
4728 	return screenpos(vc, 2 * w_offset, viewed);
4729 }
4730 EXPORT_SYMBOL_GPL(screen_pos);
4731 
4732 void getconsxy(const struct vc_data *vc, unsigned char xy[static 2])
4733 {
4734 	/* clamp values if they don't fit */
4735 	xy[0] = min(vc->state.x, 0xFFu);
4736 	xy[1] = min(vc->state.y, 0xFFu);
4737 }
4738 
4739 void putconsxy(struct vc_data *vc, unsigned char xy[static const 2])
4740 {
4741 	hide_cursor(vc);
4742 	gotoxy(vc, xy[0], xy[1]);
4743 	set_cursor(vc);
4744 }
4745 
4746 u16 vcs_scr_readw(const struct vc_data *vc, const u16 *org)
4747 {
4748 	if ((unsigned long)org == vc->vc_pos && softcursor_original != -1)
4749 		return softcursor_original;
4750 	return scr_readw(org);
4751 }
4752 
4753 void vcs_scr_writew(struct vc_data *vc, u16 val, u16 *org)
4754 {
4755 	scr_writew(val, org);
4756 	if ((unsigned long)org == vc->vc_pos) {
4757 		softcursor_original = -1;
4758 		add_softcursor(vc);
4759 	}
4760 }
4761 
4762 void vcs_scr_updated(struct vc_data *vc)
4763 {
4764 	notify_update(vc);
4765 }
4766 
4767 void vc_scrolldelta_helper(struct vc_data *c, int lines,
4768 		unsigned int rolled_over, void *base, unsigned int size)
4769 {
4770 	unsigned long ubase = (unsigned long)base;
4771 	ptrdiff_t scr_end = (void *)c->vc_scr_end - base;
4772 	ptrdiff_t vorigin = (void *)c->vc_visible_origin - base;
4773 	ptrdiff_t origin = (void *)c->vc_origin - base;
4774 	int margin = c->vc_size_row * 4;
4775 	int from, wrap, from_off, avail;
4776 
4777 	/* Turn scrollback off */
4778 	if (!lines) {
4779 		c->vc_visible_origin = c->vc_origin;
4780 		return;
4781 	}
4782 
4783 	/* Do we have already enough to allow jumping from 0 to the end? */
4784 	if (rolled_over > scr_end + margin) {
4785 		from = scr_end;
4786 		wrap = rolled_over + c->vc_size_row;
4787 	} else {
4788 		from = 0;
4789 		wrap = size;
4790 	}
4791 
4792 	from_off = (vorigin - from + wrap) % wrap + lines * c->vc_size_row;
4793 	avail = (origin - from + wrap) % wrap;
4794 
4795 	/* Only a little piece would be left? Show all incl. the piece! */
4796 	if (avail < 2 * margin)
4797 		margin = 0;
4798 	if (from_off < margin)
4799 		from_off = 0;
4800 	if (from_off > avail - margin)
4801 		from_off = avail;
4802 
4803 	c->vc_visible_origin = ubase + (from + from_off) % wrap;
4804 }
4805 EXPORT_SYMBOL_GPL(vc_scrolldelta_helper);
4806 
4807 /*
4808  *	Visible symbols for modules
4809  */
4810 
4811 EXPORT_SYMBOL(color_table);
4812 EXPORT_SYMBOL(default_red);
4813 EXPORT_SYMBOL(default_grn);
4814 EXPORT_SYMBOL(default_blu);
4815 EXPORT_SYMBOL(update_region);
4816 EXPORT_SYMBOL(redraw_screen);
4817 EXPORT_SYMBOL(vc_resize);
4818 EXPORT_SYMBOL(fg_console);
4819 EXPORT_SYMBOL(console_blank_hook);
4820 EXPORT_SYMBOL(console_blanked);
4821 EXPORT_SYMBOL(vc_cons);
4822 EXPORT_SYMBOL(global_cursor_default);
4823 #ifndef VT_SINGLE_DRIVER
4824 EXPORT_SYMBOL(give_up_console);
4825 #endif
4826