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1// SPDX-License-Identifier: GPL-2.0 or MIT
2/*
3 * Copyright (c) 2023 Red Hat.
4 * Author: Jocelyn Falempe <[email protected]>
5 * inspired by the drm_log driver from David Herrmann <[email protected]>
6 * Tux Ascii art taken from cowsay written by Tony Monroe
7 */
8
9#include <linux/export.h>
10#include <linux/font.h>
11#include <linux/highmem.h>
12#include <linux/init.h>
13#include <linux/iosys-map.h>
14#include <linux/kdebug.h>
15#include <linux/kmsg_dump.h>
16#include <linux/linux_logo.h>
17#include <linux/list.h>
18#include <linux/math.h>
19#include <linux/module.h>
20#include <linux/overflow.h>
21#include <linux/printk.h>
22#include <linux/types.h>
23#include <linux/utsname.h>
24#include <linux/zlib.h>
25
26#include <drm/drm_drv.h>
27#include <drm/drm_fourcc.h>
28#include <drm/drm_framebuffer.h>
29#include <drm/drm_modeset_helper_vtables.h>
30#include <drm/drm_panic.h>
31#include <drm/drm_plane.h>
32#include <drm/drm_print.h>
33#include <drm/drm_rect.h>
34
35#include "drm_crtc_internal.h"
36#include "drm_draw_internal.h"
37
38MODULE_AUTHOR("Jocelyn Falempe");
39MODULE_DESCRIPTION("DRM panic handler");
40MODULE_LICENSE("GPL");
41
42/**
43 * DOC: overview
44 *
45 * To enable DRM panic for a driver, the primary plane must implement a
46 * &drm_plane_helper_funcs.get_scanout_buffer helper function. It is then
47 * automatically registered to the drm panic handler.
48 * When a panic occurs, the &drm_plane_helper_funcs.get_scanout_buffer will be
49 * called, and the driver can provide a framebuffer so the panic handler can
50 * draw the panic screen on it. Currently only linear buffer and a few color
51 * formats are supported.
52 * Optionally the driver can also provide a &drm_plane_helper_funcs.panic_flush
53 * callback, that will be called after that, to send additional commands to the
54 * hardware to make the scanout buffer visible.
55 */
56
57/*
58 * This module displays a user friendly message on screen when a kernel panic
59 * occurs. This is conflicting with fbcon, so you can only enable it when fbcon
60 * is disabled.
61 * It's intended for end-user, so have minimal technical/debug information.
62 *
63 * Implementation details:
64 *
65 * It is a panic handler, so it can't take lock, allocate memory, run tasks/irq,
66 * or attempt to sleep. It's a best effort, and it may not be able to display
67 * the message in all situations (like if the panic occurs in the middle of a
68 * modesetting).
69 * It will display only one static frame, so performance optimizations are low
70 * priority as the machine is already in an unusable state.
71 */
72
73struct drm_panic_line {
74 u32 len;
75 const char *txt;
76};
77
78#define PANIC_LINE(s) {.len = sizeof(s) - 1, .txt = s}
79
80static struct drm_panic_line panic_msg[] = {
81 PANIC_LINE("KERNEL PANIC!"),
82 PANIC_LINE(""),
83 PANIC_LINE("Please reboot your computer."),
84 PANIC_LINE(""),
85 PANIC_LINE(""), /* will be replaced by the panic description */
86};
87
88static const size_t panic_msg_lines = ARRAY_SIZE(panic_msg);
89
90static const struct drm_panic_line logo_ascii[] = {
91 PANIC_LINE(" .--. _"),
92 PANIC_LINE(" |o_o | | |"),
93 PANIC_LINE(" |:_/ | | |"),
94 PANIC_LINE(" // \\ \\ |_|"),
95 PANIC_LINE(" (| | ) _"),
96 PANIC_LINE(" /'\\_ _/`\\ (_)"),
97 PANIC_LINE(" \\___)=(___/"),
98};
99
100static const size_t logo_ascii_lines = ARRAY_SIZE(logo_ascii);
101
102#if defined(CONFIG_LOGO) && !defined(MODULE)
103static const struct linux_logo *logo_mono;
104
105static int drm_panic_setup_logo(void)
106{
107 const struct linux_logo *logo = fb_find_logo(1);
108 const unsigned char *logo_data;
109 struct linux_logo *logo_dup;
110
111 if (!logo || logo->type != LINUX_LOGO_MONO)
112 return 0;
113
114 /* The logo is __init, so we must make a copy for later use */
115 logo_data = kmemdup(logo->data,
116 size_mul(DIV_ROUND_UP(logo->width, BITS_PER_BYTE), logo->height),
117 GFP_KERNEL);
118 if (!logo_data)
119 return -ENOMEM;
120
121 logo_dup = kmemdup(logo, sizeof(*logo), GFP_KERNEL);
122 if (!logo_dup) {
123 kfree(logo_data);
124 return -ENOMEM;
125 }
126
127 logo_dup->data = logo_data;
128 logo_mono = logo_dup;
129
130 return 0;
131}
132
133device_initcall(drm_panic_setup_logo);
134#else
135#define logo_mono ((const struct linux_logo *)NULL)
136#endif
137
138/*
139 * Blit & Fill functions
140 */
141static void drm_panic_blit_pixel(struct drm_scanout_buffer *sb, struct drm_rect *clip,
142 const u8 *sbuf8, unsigned int spitch, unsigned int scale,
143 u32 fg_color)
144{
145 unsigned int y, x;
146
147 for (y = 0; y < drm_rect_height(clip); y++)
148 for (x = 0; x < drm_rect_width(clip); x++)
149 if (drm_draw_is_pixel_fg(sbuf8, spitch, x / scale, y / scale))
150 sb->set_pixel(sb, clip->x1 + x, clip->y1 + y, fg_color);
151}
152
153static void drm_panic_write_pixel16(void *vaddr, unsigned int offset, u16 color)
154{
155 u16 *p = vaddr + offset;
156
157 *p = color;
158}
159
160static void drm_panic_write_pixel24(void *vaddr, unsigned int offset, u32 color)
161{
162 u8 *p = vaddr + offset;
163
164 *p++ = color & 0xff;
165 color >>= 8;
166 *p++ = color & 0xff;
167 color >>= 8;
168 *p = color & 0xff;
169}
170
171/*
172 * Special case if the pixel crosses page boundaries
173 */
174static void drm_panic_write_pixel24_xpage(void *vaddr, struct page *next_page,
175 unsigned int offset, u32 color)
176{
177 u8 *vaddr2;
178 u8 *p = vaddr + offset;
179
180 vaddr2 = kmap_local_page_try_from_panic(next_page);
181
182 *p++ = color & 0xff;
183 color >>= 8;
184
185 if (offset == PAGE_SIZE - 1)
186 p = vaddr2;
187
188 *p++ = color & 0xff;
189 color >>= 8;
190
191 if (offset == PAGE_SIZE - 2)
192 p = vaddr2;
193
194 *p = color & 0xff;
195 kunmap_local(vaddr2);
196}
197
198static void drm_panic_write_pixel32(void *vaddr, unsigned int offset, u32 color)
199{
200 u32 *p = vaddr + offset;
201
202 *p = color;
203}
204
205static void drm_panic_write_pixel(void *vaddr, unsigned int offset, u32 color, unsigned int cpp)
206{
207 switch (cpp) {
208 case 2:
209 drm_panic_write_pixel16(vaddr, offset, color);
210 break;
211 case 3:
212 drm_panic_write_pixel24(vaddr, offset, color);
213 break;
214 case 4:
215 drm_panic_write_pixel32(vaddr, offset, color);
216 break;
217 default:
218 pr_debug_once("Can't blit with pixel width %d\n", cpp);
219 }
220}
221
222/*
223 * The scanout buffer pages are not mapped, so for each pixel,
224 * use kmap_local_page_try_from_panic() to map the page, and write the pixel.
225 * Try to keep the map from the previous pixel, to avoid too much map/unmap.
226 */
227static void drm_panic_blit_page(struct page **pages, unsigned int dpitch,
228 unsigned int cpp, const u8 *sbuf8,
229 unsigned int spitch, struct drm_rect *clip,
230 unsigned int scale, u32 fg32)
231{
232 unsigned int y, x;
233 unsigned int page = ~0;
234 unsigned int height = drm_rect_height(clip);
235 unsigned int width = drm_rect_width(clip);
236 void *vaddr = NULL;
237
238 for (y = 0; y < height; y++) {
239 for (x = 0; x < width; x++) {
240 if (drm_draw_is_pixel_fg(sbuf8, spitch, x / scale, y / scale)) {
241 unsigned int new_page;
242 unsigned int offset;
243
244 offset = (y + clip->y1) * dpitch + (x + clip->x1) * cpp;
245 new_page = offset >> PAGE_SHIFT;
246 offset = offset % PAGE_SIZE;
247 if (new_page != page) {
248 if (!pages[new_page])
249 continue;
250 if (vaddr)
251 kunmap_local(vaddr);
252 page = new_page;
253 vaddr = kmap_local_page_try_from_panic(pages[page]);
254 }
255 if (!vaddr)
256 continue;
257
258 // Special case for 24bit, as a pixel might cross page boundaries
259 if (cpp == 3 && offset + 3 > PAGE_SIZE)
260 drm_panic_write_pixel24_xpage(vaddr, pages[page + 1],
261 offset, fg32);
262 else
263 drm_panic_write_pixel(vaddr, offset, fg32, cpp);
264 }
265 }
266 }
267 if (vaddr)
268 kunmap_local(vaddr);
269}
270
271/*
272 * drm_panic_blit - convert a monochrome image to a linear framebuffer
273 * @sb: destination scanout buffer
274 * @clip: destination rectangle
275 * @sbuf8: source buffer, in monochrome format, 8 pixels per byte.
276 * @spitch: source pitch in bytes
277 * @scale: integer scale, source buffer is scale time smaller than destination
278 * rectangle
279 * @fg_color: foreground color, in destination format
280 *
281 * This can be used to draw a font character, which is a monochrome image, to a
282 * framebuffer in other supported format.
283 */
284static void drm_panic_blit(struct drm_scanout_buffer *sb, struct drm_rect *clip,
285 const u8 *sbuf8, unsigned int spitch,
286 unsigned int scale, u32 fg_color)
287
288{
289 struct iosys_map map;
290
291 if (sb->set_pixel)
292 return drm_panic_blit_pixel(sb, clip, sbuf8, spitch, scale, fg_color);
293
294 if (sb->pages)
295 return drm_panic_blit_page(sb->pages, sb->pitch[0], sb->format->cpp[0],
296 sbuf8, spitch, clip, scale, fg_color);
297
298 map = sb->map[0];
299 iosys_map_incr(&map, clip->y1 * sb->pitch[0] + clip->x1 * sb->format->cpp[0]);
300
301 switch (sb->format->cpp[0]) {
302 case 2:
303 drm_draw_blit16(&map, sb->pitch[0], sbuf8, spitch,
304 drm_rect_height(clip), drm_rect_width(clip), scale, fg_color);
305 break;
306 case 3:
307 drm_draw_blit24(&map, sb->pitch[0], sbuf8, spitch,
308 drm_rect_height(clip), drm_rect_width(clip), scale, fg_color);
309 break;
310 case 4:
311 drm_draw_blit32(&map, sb->pitch[0], sbuf8, spitch,
312 drm_rect_height(clip), drm_rect_width(clip), scale, fg_color);
313 break;
314 default:
315 WARN_ONCE(1, "Can't blit with pixel width %d\n", sb->format->cpp[0]);
316 }
317}
318
319static void drm_panic_fill_pixel(struct drm_scanout_buffer *sb,
320 struct drm_rect *clip,
321 u32 color)
322{
323 unsigned int y, x;
324
325 for (y = 0; y < drm_rect_height(clip); y++)
326 for (x = 0; x < drm_rect_width(clip); x++)
327 sb->set_pixel(sb, clip->x1 + x, clip->y1 + y, color);
328}
329
330static void drm_panic_fill_page(struct page **pages, unsigned int dpitch,
331 unsigned int cpp, struct drm_rect *clip,
332 u32 color)
333{
334 unsigned int y, x;
335 unsigned int page = ~0;
336 void *vaddr = NULL;
337
338 for (y = clip->y1; y < clip->y2; y++) {
339 for (x = clip->x1; x < clip->x2; x++) {
340 unsigned int new_page;
341 unsigned int offset;
342
343 offset = y * dpitch + x * cpp;
344 new_page = offset >> PAGE_SHIFT;
345 offset = offset % PAGE_SIZE;
346 if (new_page != page) {
347 if (vaddr)
348 kunmap_local(vaddr);
349 page = new_page;
350 vaddr = kmap_local_page_try_from_panic(pages[page]);
351 }
352 if (!vaddr)
353 continue;
354
355 // Special case for 24bit, as a pixel might cross page boundaries
356 if (cpp == 3 && offset + 3 > PAGE_SIZE)
357 drm_panic_write_pixel24_xpage(vaddr, pages[page + 1],
358 offset, color);
359 else
360 drm_panic_write_pixel(vaddr, offset, color, cpp);
361 }
362 }
363 if (vaddr)
364 kunmap_local(vaddr);
365}
366
367/*
368 * drm_panic_fill - Fill a rectangle with a color
369 * @sb: destination scanout buffer
370 * @clip: destination rectangle
371 * @color: foreground color, in destination format
372 *
373 * Fill a rectangle with a color, in a linear framebuffer.
374 */
375static void drm_panic_fill(struct drm_scanout_buffer *sb, struct drm_rect *clip,
376 u32 color)
377{
378 struct iosys_map map;
379
380 if (sb->set_pixel)
381 return drm_panic_fill_pixel(sb, clip, color);
382
383 if (sb->pages)
384 return drm_panic_fill_page(sb->pages, sb->pitch[0], sb->format->cpp[0],
385 clip, color);
386
387 map = sb->map[0];
388 iosys_map_incr(&map, clip->y1 * sb->pitch[0] + clip->x1 * sb->format->cpp[0]);
389
390 switch (sb->format->cpp[0]) {
391 case 2:
392 drm_draw_fill16(&map, sb->pitch[0], drm_rect_height(clip),
393 drm_rect_width(clip), color);
394 break;
395 case 3:
396 drm_draw_fill24(&map, sb->pitch[0], drm_rect_height(clip),
397 drm_rect_width(clip), color);
398 break;
399 case 4:
400 drm_draw_fill32(&map, sb->pitch[0], drm_rect_height(clip),
401 drm_rect_width(clip), color);
402 break;
403 default:
404 WARN_ONCE(1, "Can't fill with pixel width %d\n", sb->format->cpp[0]);
405 }
406}
407
408static unsigned int get_max_line_len(const struct drm_panic_line *lines, int len)
409{
410 int i;
411 unsigned int max = 0;
412
413 for (i = 0; i < len; i++)
414 max = max(lines[i].len, max);
415 return max;
416}
417
418/*
419 * Draw a text in a rectangle on a framebuffer. The text is truncated if it overflows the rectangle
420 */
421static void draw_txt_rectangle(struct drm_scanout_buffer *sb,
422 const struct font_desc *font,
423 const struct drm_panic_line *msg,
424 unsigned int msg_lines,
425 bool centered,
426 struct drm_rect *clip,
427 u32 color)
428{
429 int i, j;
430 const u8 *src;
431 size_t font_pitch = DIV_ROUND_UP(font->width, 8);
432 struct drm_rect rec;
433
434 msg_lines = min(msg_lines, drm_rect_height(clip) / font->height);
435 for (i = 0; i < msg_lines; i++) {
436 size_t line_len = min(msg[i].len, drm_rect_width(clip) / font->width);
437
438 rec.y1 = clip->y1 + i * font->height;
439 rec.y2 = rec.y1 + font->height;
440 rec.x1 = clip->x1;
441
442 if (centered)
443 rec.x1 += (drm_rect_width(clip) - (line_len * font->width)) / 2;
444
445 for (j = 0; j < line_len; j++) {
446 src = font_data_glyph_buf(font->data, font->width, font->height,
447 (unsigned char)msg[i].txt[j]);
448 rec.x2 = rec.x1 + font->width;
449 if (src)
450 drm_panic_blit(sb, &rec, src, font_pitch, 1, color);
451 rec.x1 += font->width;
452 }
453 }
454}
455
456static void drm_panic_logo_rect(struct drm_rect *rect, const struct font_desc *font)
457{
458 if (logo_mono) {
459 drm_rect_init(rect, 0, 0, logo_mono->width, logo_mono->height);
460 } else {
461 int logo_width = get_max_line_len(logo_ascii, logo_ascii_lines) * font->width;
462
463 drm_rect_init(rect, 0, 0, logo_width, logo_ascii_lines * font->height);
464 }
465}
466
467static void drm_panic_logo_draw(struct drm_scanout_buffer *sb, struct drm_rect *rect,
468 const struct font_desc *font, u32 fg_color)
469{
470 if (rect->x2 > sb->width || rect->y2 > sb->height)
471 return;
472
473 if (logo_mono)
474 drm_panic_blit(sb, rect, logo_mono->data,
475 DIV_ROUND_UP(drm_rect_width(rect), 8), 1, fg_color);
476 else
477 draw_txt_rectangle(sb, font, logo_ascii, logo_ascii_lines, false, rect,
478 fg_color);
479}
480
481static void draw_panic_screen_user(struct drm_scanout_buffer *sb)
482{
483 u32 fg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR,
484 sb->format->format);
485 u32 bg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR,
486 sb->format->format);
487 const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
488 struct drm_rect r_screen, r_logo, r_msg;
489 unsigned int msg_width, msg_height;
490
491 if (!font)
492 return;
493
494 r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
495 drm_panic_logo_rect(&r_logo, font);
496
497 msg_width = min(get_max_line_len(panic_msg, panic_msg_lines) * font->width, sb->width);
498 msg_height = min(panic_msg_lines * font->height, sb->height);
499 r_msg = DRM_RECT_INIT(0, 0, msg_width, msg_height);
500
501 /* Center the panic message */
502 drm_rect_translate(&r_msg, (sb->width - r_msg.x2) / 2, (sb->height - r_msg.y2) / 2);
503
504 /* Fill with the background color, and draw text on top */
505 drm_panic_fill(sb, &r_screen, bg_color);
506
507 if (!drm_rect_overlap(&r_logo, &r_msg))
508 drm_panic_logo_draw(sb, &r_logo, font, fg_color);
509
510 draw_txt_rectangle(sb, font, panic_msg, panic_msg_lines, true, &r_msg, fg_color);
511}
512
513/*
514 * Draw one line of kmsg, and handle wrapping if it won't fit in the screen width.
515 * Return the y-offset of the next line.
516 */
517static int draw_line_with_wrap(struct drm_scanout_buffer *sb, const struct font_desc *font,
518 struct drm_panic_line *line, int yoffset, u32 fg_color)
519{
520 int chars_per_row = sb->width / font->width;
521 struct drm_rect r_txt = DRM_RECT_INIT(0, yoffset, sb->width, font->height);
522 struct drm_panic_line line_wrap;
523
524 if (line->len > chars_per_row) {
525 line_wrap.len = line->len % chars_per_row;
526 line_wrap.txt = line->txt + line->len - line_wrap.len;
527 draw_txt_rectangle(sb, font, &line_wrap, 1, false, &r_txt, fg_color);
528 r_txt.y1 -= font->height;
529 if (r_txt.y1 < 0)
530 return r_txt.y1;
531 while (line_wrap.txt > line->txt) {
532 line_wrap.txt -= chars_per_row;
533 line_wrap.len = chars_per_row;
534 draw_txt_rectangle(sb, font, &line_wrap, 1, false, &r_txt, fg_color);
535 r_txt.y1 -= font->height;
536 if (r_txt.y1 < 0)
537 return r_txt.y1;
538 }
539 } else {
540 draw_txt_rectangle(sb, font, line, 1, false, &r_txt, fg_color);
541 r_txt.y1 -= font->height;
542 }
543 return r_txt.y1;
544}
545
546/*
547 * Draw the kmsg buffer to the screen, starting from the youngest message at the bottom,
548 * and going up until reaching the top of the screen.
549 */
550static void draw_panic_screen_kmsg(struct drm_scanout_buffer *sb)
551{
552 u32 fg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR,
553 sb->format->format);
554 u32 bg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR,
555 sb->format->format);
556 const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
557 struct drm_rect r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
558 struct kmsg_dump_iter iter;
559 char kmsg_buf[512];
560 size_t kmsg_len;
561 struct drm_panic_line line;
562 int yoffset;
563
564 if (!font || font->width > sb->width)
565 return;
566
567 yoffset = sb->height - font->height - (sb->height % font->height) / 2;
568
569 /* Fill with the background color, and draw text on top */
570 drm_panic_fill(sb, &r_screen, bg_color);
571
572 kmsg_dump_rewind(&iter);
573 while (kmsg_dump_get_buffer(&iter, false, kmsg_buf, sizeof(kmsg_buf), &kmsg_len)) {
574 char *start;
575 char *end;
576
577 /* ignore terminating NUL and newline */
578 start = kmsg_buf + kmsg_len - 2;
579 end = kmsg_buf + kmsg_len - 1;
580 while (start > kmsg_buf && yoffset >= 0) {
581 while (start > kmsg_buf && *start != '\n')
582 start--;
583 /* don't count the newline character */
584 line.txt = start + (start == kmsg_buf ? 0 : 1);
585 line.len = end - line.txt;
586
587 yoffset = draw_line_with_wrap(sb, font, &line, yoffset, fg_color);
588 end = start;
589 start--;
590 }
591 }
592}
593
594#if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
595/*
596 * It is unwise to allocate memory in the panic callback, so the buffers are
597 * pre-allocated. Only 2 buffers and the zlib workspace are needed.
598 * Two buffers are enough, using the following buffer usage:
599 * 1) kmsg messages are dumped in buffer1
600 * 2) kmsg is zlib-compressed into buffer2
601 * 3) compressed kmsg is encoded as QR-code Numeric stream in buffer1
602 * 4) QR-code image is generated in buffer2
603 * The Max QR code size is V40, 177x177, 4071 bytes for image, 2956 bytes for
604 * data segments.
605 *
606 * Typically, ~7500 bytes of kmsg, are compressed into 2800 bytes, which fits in
607 * a V40 QR-code (177x177).
608 *
609 * If CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL is not set, the kmsg data will be put
610 * directly in the QR code.
611 * 1) kmsg messages are dumped in buffer1
612 * 2) kmsg message is encoded as byte stream in buffer2
613 * 3) QR-code image is generated in buffer1
614 */
615
616static uint panic_qr_version = CONFIG_DRM_PANIC_SCREEN_QR_VERSION;
617module_param(panic_qr_version, uint, 0644);
618MODULE_PARM_DESC(panic_qr_version, "maximum version (size) of the QR code");
619
620#define MAX_QR_DATA 2956
621#define MAX_ZLIB_RATIO 3
622#define QR_BUFFER1_SIZE (MAX_ZLIB_RATIO * MAX_QR_DATA) /* Must also be > 4071 */
623#define QR_BUFFER2_SIZE 4096
624#define QR_MARGIN 4 /* 4 modules of foreground color around the qr code */
625
626/* Compression parameters */
627#define COMPR_LEVEL 6
628#define WINDOW_BITS 12
629#define MEM_LEVEL 4
630
631static char *qrbuf1;
632static char *qrbuf2;
633static struct z_stream_s stream;
634
635static void __init drm_panic_qr_init(void)
636{
637 qrbuf1 = kmalloc(QR_BUFFER1_SIZE, GFP_KERNEL);
638 qrbuf2 = kmalloc(QR_BUFFER2_SIZE, GFP_KERNEL);
639 stream.workspace = kmalloc(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL),
640 GFP_KERNEL);
641}
642
643static void drm_panic_qr_exit(void)
644{
645 kfree(qrbuf1);
646 qrbuf1 = NULL;
647 kfree(qrbuf2);
648 qrbuf2 = NULL;
649 kfree(stream.workspace);
650 stream.workspace = NULL;
651}
652
653static int drm_panic_get_qr_code_url(u8 **qr_image)
654{
655 struct kmsg_dump_iter iter;
656 char url[256];
657 size_t kmsg_len, max_kmsg_size;
658 char *kmsg;
659 int max_qr_data_size, url_len;
660
661 url_len = snprintf(url, sizeof(url), CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL "?a=%s&v=%s&z=",
662 utsname()->machine, utsname()->release);
663
664 max_qr_data_size = drm_panic_qr_max_data_size(panic_qr_version, url_len);
665 max_kmsg_size = min(MAX_ZLIB_RATIO * max_qr_data_size, QR_BUFFER1_SIZE);
666
667 /* get kmsg to buffer 1 */
668 kmsg_dump_rewind(&iter);
669 kmsg_dump_get_buffer(&iter, false, qrbuf1, max_kmsg_size, &kmsg_len);
670
671 if (!kmsg_len)
672 return -ENODATA;
673 kmsg = qrbuf1;
674
675try_again:
676 if (zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS,
677 MEM_LEVEL, Z_DEFAULT_STRATEGY) != Z_OK)
678 return -EINVAL;
679
680 stream.next_in = kmsg;
681 stream.avail_in = kmsg_len;
682 stream.total_in = 0;
683 stream.next_out = qrbuf2;
684 stream.avail_out = QR_BUFFER2_SIZE;
685 stream.total_out = 0;
686
687 if (zlib_deflate(&stream, Z_FINISH) != Z_STREAM_END)
688 return -EINVAL;
689
690 if (zlib_deflateEnd(&stream) != Z_OK)
691 return -EINVAL;
692
693 if (stream.total_out > max_qr_data_size) {
694 /* too much data for the QR code, so skip the first line and try again */
695 kmsg = strchr(kmsg, '\n');
696 if (!kmsg)
697 return -EINVAL;
698 /* skip the first \n */
699 kmsg += 1;
700 kmsg_len = strlen(kmsg);
701 goto try_again;
702 }
703 *qr_image = qrbuf2;
704
705 /* generate qr code image in buffer2 */
706 return drm_panic_qr_generate(url, qrbuf2, stream.total_out, QR_BUFFER2_SIZE,
707 qrbuf1, QR_BUFFER1_SIZE);
708}
709
710static int drm_panic_get_qr_code_raw(u8 **qr_image)
711{
712 struct kmsg_dump_iter iter;
713 size_t kmsg_len;
714 size_t max_kmsg_size = min(drm_panic_qr_max_data_size(panic_qr_version, 0),
715 QR_BUFFER1_SIZE);
716
717 kmsg_dump_rewind(&iter);
718 kmsg_dump_get_buffer(&iter, false, qrbuf1, max_kmsg_size, &kmsg_len);
719 if (!kmsg_len)
720 return -ENODATA;
721
722 *qr_image = qrbuf1;
723 return drm_panic_qr_generate(NULL, qrbuf1, kmsg_len, QR_BUFFER1_SIZE,
724 qrbuf2, QR_BUFFER2_SIZE);
725}
726
727static int drm_panic_get_qr_code(u8 **qr_image)
728{
729 if (strlen(CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL) > 0)
730 return drm_panic_get_qr_code_url(qr_image);
731 else
732 return drm_panic_get_qr_code_raw(qr_image);
733}
734
735/*
736 * Draw the panic message at the center of the screen, with a QR Code
737 */
738static int _draw_panic_screen_qr_code(struct drm_scanout_buffer *sb)
739{
740 u32 fg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR,
741 sb->format->format);
742 u32 bg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR,
743 sb->format->format);
744 const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
745 struct drm_rect r_screen, r_logo, r_msg, r_qr, r_qr_canvas;
746 unsigned int max_qr_size, scale;
747 unsigned int msg_width, msg_height;
748 int qr_width, qr_canvas_width, qr_pitch, v_margin;
749 u8 *qr_image;
750
751 if (!font || !qrbuf1 || !qrbuf2 || !stream.workspace)
752 return -ENOMEM;
753
754 r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
755
756 drm_panic_logo_rect(&r_logo, font);
757
758 msg_width = min(get_max_line_len(panic_msg, panic_msg_lines) * font->width, sb->width);
759 msg_height = min(panic_msg_lines * font->height, sb->height);
760 r_msg = DRM_RECT_INIT(0, 0, msg_width, msg_height);
761
762 max_qr_size = min(3 * sb->width / 4, 3 * sb->height / 4);
763
764 qr_width = drm_panic_get_qr_code(&qr_image);
765 if (qr_width <= 0)
766 return -ENOSPC;
767
768 qr_canvas_width = qr_width + QR_MARGIN * 2;
769 scale = max_qr_size / qr_canvas_width;
770 /* QR code is not readable if not scaled at least by 2 */
771 if (scale < 2)
772 return -ENOSPC;
773
774 pr_debug("QR width %d and scale %d\n", qr_width, scale);
775 r_qr_canvas = DRM_RECT_INIT(0, 0, qr_canvas_width * scale, qr_canvas_width * scale);
776
777 v_margin = sb->height - drm_rect_height(&r_qr_canvas) - drm_rect_height(&r_msg);
778 if (v_margin < 0)
779 return -ENOSPC;
780 v_margin /= 5;
781
782 drm_rect_translate(&r_qr_canvas, (sb->width - r_qr_canvas.x2) / 2, 2 * v_margin);
783 r_qr = DRM_RECT_INIT(r_qr_canvas.x1 + QR_MARGIN * scale, r_qr_canvas.y1 + QR_MARGIN * scale,
784 qr_width * scale, qr_width * scale);
785
786 /* Center the panic message */
787 drm_rect_translate(&r_msg, (sb->width - r_msg.x2) / 2,
788 3 * v_margin + drm_rect_height(&r_qr_canvas));
789
790 /* Fill with the background color, and draw text on top */
791 drm_panic_fill(sb, &r_screen, bg_color);
792
793 if (!drm_rect_overlap(&r_logo, &r_msg) && !drm_rect_overlap(&r_logo, &r_qr_canvas))
794 drm_panic_logo_draw(sb, &r_logo, font, fg_color);
795
796 draw_txt_rectangle(sb, font, panic_msg, panic_msg_lines, true, &r_msg, fg_color);
797
798 /* Draw the qr code */
799 qr_pitch = DIV_ROUND_UP(qr_width, 8);
800 drm_panic_fill(sb, &r_qr_canvas, fg_color);
801 drm_panic_fill(sb, &r_qr, bg_color);
802 drm_panic_blit(sb, &r_qr, qr_image, qr_pitch, scale, fg_color);
803 return 0;
804}
805
806static void draw_panic_screen_qr_code(struct drm_scanout_buffer *sb)
807{
808 if (_draw_panic_screen_qr_code(sb))
809 draw_panic_screen_user(sb);
810}
811#else
812static void drm_panic_qr_init(void) {};
813static void drm_panic_qr_exit(void) {};
814#endif
815
816enum drm_panic_type {
817 DRM_PANIC_TYPE_KMSG,
818 DRM_PANIC_TYPE_USER,
819 DRM_PANIC_TYPE_QR,
820};
821
822static enum drm_panic_type drm_panic_type = -1;
823
824static const char *drm_panic_type_map[] = {
825 [DRM_PANIC_TYPE_KMSG] = "kmsg",
826 [DRM_PANIC_TYPE_USER] = "user",
827#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
828 [DRM_PANIC_TYPE_QR] = "qr_code",
829#endif
830};
831
832static int drm_panic_type_set(const char *val, const struct kernel_param *kp)
833{
834 unsigned int i;
835
836 for (i = 0; i < ARRAY_SIZE(drm_panic_type_map); i++) {
837 if (!strcmp(val, drm_panic_type_map[i])) {
838 drm_panic_type = i;
839 return 0;
840 }
841 }
842
843 return -EINVAL;
844}
845
846static int drm_panic_type_get(char *buffer, const struct kernel_param *kp)
847{
848 return scnprintf(buffer, PAGE_SIZE, "%s\n",
849 drm_panic_type_map[drm_panic_type]);
850}
851
852static const struct kernel_param_ops drm_panic_ops = {
853 .set = drm_panic_type_set,
854 .get = drm_panic_type_get,
855};
856
857module_param_cb(panic_screen, &drm_panic_ops, NULL, 0644);
858MODULE_PARM_DESC(panic_screen,
859#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
860 "Choose what will be displayed by drm_panic, 'user', 'kmsg' or 'qr_code' [default="
861#else
862 "Choose what will be displayed by drm_panic, 'user' or 'kmsg' [default="
863#endif
864 CONFIG_DRM_PANIC_SCREEN "]");
865
866/*
867 * drm_panic_is_format_supported()
868 * @format: a fourcc color code
869 * Returns: true if supported, false otherwise.
870 *
871 * Check if drm_panic will be able to use this color format.
872 */
873static bool drm_panic_is_format_supported(const struct drm_format_info *format)
874{
875 if (format->num_planes != 1)
876 return false;
877 return drm_draw_can_convert_from_xrgb8888(format->format);
878}
879
880static void draw_panic_dispatch(struct drm_scanout_buffer *sb)
881{
882 switch (drm_panic_type) {
883 case DRM_PANIC_TYPE_KMSG:
884 draw_panic_screen_kmsg(sb);
885 break;
886
887#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
888 case DRM_PANIC_TYPE_QR:
889 draw_panic_screen_qr_code(sb);
890 break;
891#endif
892
893 case DRM_PANIC_TYPE_USER:
894 default:
895 draw_panic_screen_user(sb);
896 }
897}
898
899static void drm_panic_set_description(const char *description)
900{
901 u32 len;
902
903 if (description) {
904 struct drm_panic_line *desc_line = &panic_msg[panic_msg_lines - 1];
905
906 desc_line->txt = description;
907 len = strlen(description);
908 /* ignore the last newline character */
909 if (len && description[len - 1] == '\n')
910 len -= 1;
911 desc_line->len = len;
912 }
913}
914
915static void drm_panic_clear_description(void)
916{
917 struct drm_panic_line *desc_line = &panic_msg[panic_msg_lines - 1];
918
919 desc_line->len = 0;
920 desc_line->txt = NULL;
921}
922
923static void draw_panic_plane(struct drm_plane *plane, const char *description)
924{
925 struct drm_scanout_buffer sb = { };
926 int ret;
927 unsigned long flags;
928
929 if (!drm_panic_trylock(plane->dev, flags))
930 return;
931
932 ret = plane->helper_private->get_scanout_buffer(plane, &sb);
933
934 if (ret || !drm_panic_is_format_supported(sb.format))
935 goto unlock;
936
937 /* One of these should be set, or it can't draw pixels */
938 if (!sb.set_pixel && !sb.pages && iosys_map_is_null(&sb.map[0]))
939 goto unlock;
940
941 drm_panic_set_description(description);
942
943 draw_panic_dispatch(&sb);
944 if (plane->helper_private->panic_flush)
945 plane->helper_private->panic_flush(plane);
946
947 drm_panic_clear_description();
948
949unlock:
950 drm_panic_unlock(plane->dev, flags);
951}
952
953static struct drm_plane *to_drm_plane(struct kmsg_dumper *kd)
954{
955 return container_of(kd, struct drm_plane, kmsg_panic);
956}
957
958static void drm_panic(struct kmsg_dumper *dumper, struct kmsg_dump_detail *detail)
959{
960 struct drm_plane *plane = to_drm_plane(dumper);
961
962 if (detail->reason == KMSG_DUMP_PANIC)
963 draw_panic_plane(plane, detail->description);
964}
965
966
967/*
968 * DEBUG FS, This is currently unsafe.
969 * Create one file per plane, so it's possible to debug one plane at a time.
970 * TODO: It would be better to emulate an NMI context.
971 */
972#ifdef CONFIG_DRM_PANIC_DEBUG
973#include <linux/debugfs.h>
974
975static ssize_t debugfs_trigger_write(struct file *file, const char __user *user_buf,
976 size_t count, loff_t *ppos)
977{
978 bool run;
979
980 if (kstrtobool_from_user(user_buf, count, &run) == 0 && run) {
981 struct drm_plane *plane = file->private_data;
982
983 draw_panic_plane(plane, "Test from debugfs");
984 }
985 return count;
986}
987
988static const struct file_operations dbg_drm_panic_ops = {
989 .owner = THIS_MODULE,
990 .write = debugfs_trigger_write,
991 .open = simple_open,
992};
993
994static void debugfs_register_plane(struct drm_plane *plane, int index)
995{
996 char fname[32];
997
998 snprintf(fname, 32, "drm_panic_plane_%d", index);
999 debugfs_create_file(fname, 0200, plane->dev->debugfs_root,
1000 plane, &dbg_drm_panic_ops);
1001}
1002#else
1003static void debugfs_register_plane(struct drm_plane *plane, int index) {}
1004#endif /* CONFIG_DRM_PANIC_DEBUG */
1005
1006/**
1007 * drm_panic_is_enabled
1008 * @dev: the drm device that may supports drm_panic
1009 *
1010 * returns true if the drm device supports drm_panic
1011 */
1012bool drm_panic_is_enabled(struct drm_device *dev)
1013{
1014 struct drm_plane *plane;
1015
1016 if (!dev->mode_config.num_total_plane)
1017 return false;
1018
1019 drm_for_each_plane(plane, dev)
1020 if (plane->helper_private && plane->helper_private->get_scanout_buffer)
1021 return true;
1022 return false;
1023}
1024EXPORT_SYMBOL(drm_panic_is_enabled);
1025
1026/**
1027 * drm_panic_register() - Initialize DRM panic for a device
1028 * @dev: the drm device on which the panic screen will be displayed.
1029 */
1030void drm_panic_register(struct drm_device *dev)
1031{
1032 struct drm_plane *plane;
1033 int registered_plane = 0;
1034
1035 if (!dev->mode_config.num_total_plane)
1036 return;
1037
1038 drm_for_each_plane(plane, dev) {
1039 if (!plane->helper_private || !plane->helper_private->get_scanout_buffer)
1040 continue;
1041 plane->kmsg_panic.dump = drm_panic;
1042 plane->kmsg_panic.max_reason = KMSG_DUMP_PANIC;
1043 if (kmsg_dump_register(&plane->kmsg_panic))
1044 drm_warn(dev, "Failed to register panic handler\n");
1045 else {
1046 debugfs_register_plane(plane, registered_plane);
1047 registered_plane++;
1048 }
1049 }
1050 if (registered_plane)
1051 drm_info(dev, "Registered %d planes with drm panic\n", registered_plane);
1052}
1053
1054/**
1055 * drm_panic_unregister()
1056 * @dev: the drm device previously registered.
1057 */
1058void drm_panic_unregister(struct drm_device *dev)
1059{
1060 struct drm_plane *plane;
1061
1062 if (!dev->mode_config.num_total_plane)
1063 return;
1064
1065 drm_for_each_plane(plane, dev) {
1066 if (!plane->helper_private || !plane->helper_private->get_scanout_buffer)
1067 continue;
1068 kmsg_dump_unregister(&plane->kmsg_panic);
1069 }
1070}
1071
1072/**
1073 * drm_panic_init() - initialize DRM panic.
1074 */
1075void __init drm_panic_init(void)
1076{
1077 if (drm_panic_type == -1 && drm_panic_type_set(CONFIG_DRM_PANIC_SCREEN, NULL)) {
1078 pr_warn("Unsupported value for CONFIG_DRM_PANIC_SCREEN ('%s'), falling back to 'user'...\n",
1079 CONFIG_DRM_PANIC_SCREEN);
1080 drm_panic_type = DRM_PANIC_TYPE_USER;
1081 }
1082 drm_panic_qr_init();
1083}
1084
1085/**
1086 * drm_panic_exit() - Free the resources taken by drm_panic_exit()
1087 */
1088void drm_panic_exit(void)
1089{
1090 drm_panic_qr_exit();
1091}
1092
1093#ifdef CONFIG_DRM_KUNIT_TEST
1094#include "tests/drm_panic_test.c"
1095#endif