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