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