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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#include <linux/export.h>#include <linux/font.h>#include <linux/highmem.h>#include <linux/init.h>#include <linux/iosys-map.h>#include <linux/kdebug.h>#include <linux/kmsg_dump.h>#include <linux/linux_logo.h>#include <linux/list.h>#include <linux/math.h>#include <linux/module.h>#include <linux/overflow.h>#include <linux/printk.h>#include <linux/types.h>#include <linux/utsname.h>#include <linux/zlib.h>
#include <drm/drm_drv.h>#include <drm/drm_fourcc.h>#include <drm/drm_framebuffer.h>#include <drm/drm_modeset_helper_vtables.h>#include <drm/drm_panic.h>#include <drm/drm_plane.h>#include <drm/drm_print.h>#include <drm/drm_rect.h>
#include "drm_crtc_internal.h"#include "drm_draw_internal.h"
MODULE_AUTHOR("Jocelyn Falempe");MODULE_DESCRIPTION("DRM panic handler");MODULE_LICENSE("GPL");
/** * DOC: overview * * To enable DRM panic for a driver, the primary plane must implement a * &drm_plane_helper_funcs.get_scanout_buffer helper function. It is then * automatically registered to the drm panic handler. * When a panic occurs, the &drm_plane_helper_funcs.get_scanout_buffer will be * called, and the driver can provide a framebuffer so the panic handler can * draw the panic screen on it. Currently only linear buffer and a few color * formats are supported. * Optionally the driver can also provide a &drm_plane_helper_funcs.panic_flush * callback, that will be called after that, to send additional commands to the * hardware to make the scanout buffer visible. */
/* * This module displays a user friendly message on screen when a kernel panic * occurs. This is conflicting with fbcon, so you can only enable it when fbcon * is disabled. * It's intended for end-user, so have minimal technical/debug information. * * Implementation details: * * It is a panic handler, so it can't take lock, allocate memory, run tasks/irq, * or attempt to sleep. It's a best effort, and it may not be able to display * the message in all situations (like if the panic occurs in the middle of a * modesetting). * It will display only one static frame, so performance optimizations are low * priority as the machine is already in an unusable state. */
struct drm_panic_line { u32 len; const char *txt;};
#define PANIC_LINE(s) {.len = sizeof(s) - 1, .txt = s}
static struct drm_panic_line panic_msg[] = { PANIC_LINE("KERNEL PANIC!"), PANIC_LINE(""), PANIC_LINE("Please reboot your computer."), PANIC_LINE(""), PANIC_LINE(""), /* will be replaced by the panic description */};
static const size_t panic_msg_lines = ARRAY_SIZE(panic_msg);
static const struct drm_panic_line logo_ascii[] = { PANIC_LINE(" .--. _"), PANIC_LINE(" |o_o | | |"), PANIC_LINE(" |:_/ | | |"), PANIC_LINE(" // \\ \\ |_|"), PANIC_LINE(" (| | ) _"), PANIC_LINE(" /'\\_ _/`\\ (_)"), PANIC_LINE(" \\___)=(___/"),};
static const size_t logo_ascii_lines = ARRAY_SIZE(logo_ascii);
#if defined(CONFIG_LOGO) && !defined(MODULE)static const struct linux_logo *logo_mono;
static int drm_panic_setup_logo(void){ const struct linux_logo *logo = fb_find_logo(1); const unsigned char *logo_data; struct linux_logo *logo_dup;
if (!logo || logo->type != LINUX_LOGO_MONO) return 0;
/* The logo is __init, so we must make a copy for later use */ logo_data = kmemdup(logo->data, size_mul(DIV_ROUND_UP(logo->width, BITS_PER_BYTE), logo->height), GFP_KERNEL); if (!logo_data) return -ENOMEM;
logo_dup = kmemdup(logo, sizeof(*logo), GFP_KERNEL); if (!logo_dup) { kfree(logo_data); return -ENOMEM; }
logo_dup->data = logo_data; logo_mono = logo_dup;
return 0;}
device_initcall(drm_panic_setup_logo);#else#define logo_mono ((const struct linux_logo *)NULL)#endif
/* * Blit & Fill functions */static void drm_panic_blit_pixel(struct drm_scanout_buffer *sb, struct drm_rect *clip, const u8 *sbuf8, unsigned int spitch, unsigned int scale, u32 fg_color){ unsigned int y, x;
for (y = 0; y < drm_rect_height(clip); y++) for (x = 0; x < drm_rect_width(clip); x++) if (drm_draw_is_pixel_fg(sbuf8, spitch, x / scale, y / scale)) sb->set_pixel(sb, clip->x1 + x, clip->y1 + y, fg_color);}
static void drm_panic_write_pixel16(void *vaddr, unsigned int offset, u16 color){ u16 *p = vaddr + offset;
*p = color;}
static void drm_panic_write_pixel24(void *vaddr, unsigned int offset, u32 color){ u8 *p = vaddr + offset;
*p++ = color & 0xff; color >>= 8; *p++ = color & 0xff; color >>= 8; *p = color & 0xff;}
/* * Special case if the pixel crosses page boundaries */static void drm_panic_write_pixel24_xpage(void *vaddr, struct page *next_page, unsigned int offset, u32 color){ u8 *vaddr2; u8 *p = vaddr + offset;
vaddr2 = kmap_local_page_try_from_panic(next_page);
*p++ = color & 0xff; color >>= 8;
if (offset == PAGE_SIZE - 1) p = vaddr2;
*p++ = color & 0xff; color >>= 8;
if (offset == PAGE_SIZE - 2) p = vaddr2;
*p = color & 0xff; kunmap_local(vaddr2);}
static void drm_panic_write_pixel32(void *vaddr, unsigned int offset, u32 color){ u32 *p = vaddr + offset;
*p = color;}
static void drm_panic_write_pixel(void *vaddr, unsigned int offset, u32 color, unsigned int cpp){ switch (cpp) { case 2: drm_panic_write_pixel16(vaddr, offset, color); break; case 3: drm_panic_write_pixel24(vaddr, offset, color); break; case 4: drm_panic_write_pixel32(vaddr, offset, color); break; default: pr_debug_once("Can't blit with pixel width %d\n", cpp); }}
/* * The scanout buffer pages are not mapped, so for each pixel, * use kmap_local_page_try_from_panic() to map the page, and write the pixel. * Try to keep the map from the previous pixel, to avoid too much map/unmap. */static void drm_panic_blit_page(struct page **pages, unsigned int dpitch, unsigned int cpp, const u8 *sbuf8, unsigned int spitch, struct drm_rect *clip, unsigned int scale, u32 fg32){ unsigned int y, x; unsigned int page = ~0; unsigned int height = drm_rect_height(clip); unsigned int width = drm_rect_width(clip); void *vaddr = NULL;
for (y = 0; y < height; y++) { for (x = 0; x < width; x++) { if (drm_draw_is_pixel_fg(sbuf8, spitch, x / scale, y / scale)) { unsigned int new_page; unsigned int offset;
offset = (y + clip->y1) * dpitch + (x + clip->x1) * cpp; new_page = offset >> PAGE_SHIFT; offset = offset % PAGE_SIZE; if (new_page != page) { if (!pages[new_page]) continue; if (vaddr) kunmap_local(vaddr); page = new_page; vaddr = kmap_local_page_try_from_panic(pages[page]); } if (!vaddr) continue;
// Special case for 24bit, as a pixel might cross page boundaries if (cpp == 3 && offset + 3 > PAGE_SIZE) drm_panic_write_pixel24_xpage(vaddr, pages[page + 1], offset, fg32); else drm_panic_write_pixel(vaddr, offset, fg32, cpp); } } } if (vaddr) kunmap_local(vaddr);}
/* * drm_panic_blit - convert a monochrome image to a linear framebuffer * @sb: destination scanout buffer * @clip: destination rectangle * @sbuf8: source buffer, in monochrome format, 8 pixels per byte. * @spitch: source pitch in bytes * @scale: integer scale, source buffer is scale time smaller than destination * rectangle * @fg_color: foreground color, in destination format * * This can be used to draw a font character, which is a monochrome image, to a * framebuffer in other supported format. */static void drm_panic_blit(struct drm_scanout_buffer *sb, struct drm_rect *clip, const u8 *sbuf8, unsigned int spitch, unsigned int scale, u32 fg_color)
{ struct iosys_map map;
if (sb->set_pixel) return drm_panic_blit_pixel(sb, clip, sbuf8, spitch, scale, fg_color);
if (sb->pages) return drm_panic_blit_page(sb->pages, sb->pitch[0], sb->format->cpp[0], sbuf8, spitch, clip, scale, fg_color);
map = sb->map[0]; iosys_map_incr(&map, clip->y1 * sb->pitch[0] + clip->x1 * sb->format->cpp[0]);
switch (sb->format->cpp[0]) { case 2: drm_draw_blit16(&map, sb->pitch[0], sbuf8, spitch, drm_rect_height(clip), drm_rect_width(clip), scale, fg_color); break; case 3: drm_draw_blit24(&map, sb->pitch[0], sbuf8, spitch, drm_rect_height(clip), drm_rect_width(clip), scale, fg_color); break; case 4: drm_draw_blit32(&map, sb->pitch[0], sbuf8, spitch, drm_rect_height(clip), drm_rect_width(clip), scale, fg_color); break; default: WARN_ONCE(1, "Can't blit with pixel width %d\n", sb->format->cpp[0]); }}
static void drm_panic_fill_pixel(struct drm_scanout_buffer *sb, struct drm_rect *clip, u32 color){ unsigned int y, x;
for (y = 0; y < drm_rect_height(clip); y++) for (x = 0; x < drm_rect_width(clip); x++) sb->set_pixel(sb, clip->x1 + x, clip->y1 + y, color);}
static void drm_panic_fill_page(struct page **pages, unsigned int dpitch, unsigned int cpp, struct drm_rect *clip, u32 color){ unsigned int y, x; unsigned int page = ~0; void *vaddr = NULL;
for (y = clip->y1; y < clip->y2; y++) { for (x = clip->x1; x < clip->x2; x++) { unsigned int new_page; unsigned int offset;
offset = y * dpitch + x * cpp; new_page = offset >> PAGE_SHIFT; offset = offset % PAGE_SIZE; if (new_page != page) { if (vaddr) kunmap_local(vaddr); page = new_page; vaddr = kmap_local_page_try_from_panic(pages[page]); } if (!vaddr) continue;
// Special case for 24bit, as a pixel might cross page boundaries if (cpp == 3 && offset + 3 > PAGE_SIZE) drm_panic_write_pixel24_xpage(vaddr, pages[page + 1], offset, color); else drm_panic_write_pixel(vaddr, offset, color, cpp); } } if (vaddr) kunmap_local(vaddr);}
/* * drm_panic_fill - Fill a rectangle with a color * @sb: destination scanout buffer * @clip: destination rectangle * @color: foreground color, in destination format * * Fill a rectangle with a color, in a linear framebuffer. */static void drm_panic_fill(struct drm_scanout_buffer *sb, struct drm_rect *clip, u32 color){ struct iosys_map map;
if (sb->set_pixel) return drm_panic_fill_pixel(sb, clip, color);
if (sb->pages) return drm_panic_fill_page(sb->pages, sb->pitch[0], sb->format->cpp[0], clip, color);
map = sb->map[0]; iosys_map_incr(&map, clip->y1 * sb->pitch[0] + clip->x1 * sb->format->cpp[0]);
switch (sb->format->cpp[0]) { case 2: drm_draw_fill16(&map, sb->pitch[0], drm_rect_height(clip), drm_rect_width(clip), color); break; case 3: drm_draw_fill24(&map, sb->pitch[0], drm_rect_height(clip), drm_rect_width(clip), color); break; case 4: drm_draw_fill32(&map, sb->pitch[0], drm_rect_height(clip), drm_rect_width(clip), color); break; default: WARN_ONCE(1, "Can't fill with pixel width %d\n", sb->format->cpp[0]); }}
static unsigned int get_max_line_len(const struct drm_panic_line *lines, int len){ int i; unsigned int max = 0;
for (i = 0; i < len; i++) max = max(lines[i].len, max); return max;}
/* * Draw a text in a rectangle on a framebuffer. The text is truncated if it overflows the rectangle */static void draw_txt_rectangle(struct drm_scanout_buffer *sb, const struct font_desc *font, const struct drm_panic_line *msg, unsigned int msg_lines, bool centered, struct drm_rect *clip, u32 color){ int i, j; const u8 *src; size_t font_pitch = DIV_ROUND_UP(font->width, 8); struct drm_rect rec;
msg_lines = min(msg_lines, drm_rect_height(clip) / font->height); for (i = 0; i < msg_lines; i++) { size_t line_len = min(msg[i].len, drm_rect_width(clip) / font->width);
rec.y1 = clip->y1 + i * font->height; rec.y2 = rec.y1 + font->height; rec.x1 = clip->x1;
if (centered) rec.x1 += (drm_rect_width(clip) - (line_len * font->width)) / 2;
for (j = 0; j < line_len; j++) { src = drm_draw_get_char_bitmap(font, msg[i].txt[j], font_pitch); rec.x2 = rec.x1 + font->width; drm_panic_blit(sb, &rec, src, font_pitch, 1, color); rec.x1 += font->width; } }}
static void drm_panic_logo_rect(struct drm_rect *rect, const struct font_desc *font){ if (logo_mono) { drm_rect_init(rect, 0, 0, logo_mono->width, logo_mono->height); } else { int logo_width = get_max_line_len(logo_ascii, logo_ascii_lines) * font->width;
drm_rect_init(rect, 0, 0, logo_width, logo_ascii_lines * font->height); }}
static void drm_panic_logo_draw(struct drm_scanout_buffer *sb, struct drm_rect *rect, const struct font_desc *font, u32 fg_color){ if (rect->x2 > sb->width || rect->y2 > sb->height) return;
if (logo_mono) drm_panic_blit(sb, rect, logo_mono->data, DIV_ROUND_UP(drm_rect_width(rect), 8), 1, fg_color); else draw_txt_rectangle(sb, font, logo_ascii, logo_ascii_lines, false, rect, fg_color);}
static void draw_panic_screen_user(struct drm_scanout_buffer *sb){ u32 fg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR, sb->format->format); u32 bg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR, sb->format->format); const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL); struct drm_rect r_screen, r_logo, r_msg; unsigned int msg_width, msg_height;
if (!font) return;
r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height); drm_panic_logo_rect(&r_logo, font);
msg_width = min(get_max_line_len(panic_msg, panic_msg_lines) * font->width, sb->width); msg_height = min(panic_msg_lines * font->height, sb->height); r_msg = DRM_RECT_INIT(0, 0, msg_width, msg_height);
/* Center the panic message */ drm_rect_translate(&r_msg, (sb->width - r_msg.x2) / 2, (sb->height - r_msg.y2) / 2);
/* Fill with the background color, and draw text on top */ drm_panic_fill(sb, &r_screen, bg_color);
if (!drm_rect_overlap(&r_logo, &r_msg)) drm_panic_logo_draw(sb, &r_logo, font, fg_color);
draw_txt_rectangle(sb, font, panic_msg, panic_msg_lines, true, &r_msg, fg_color);}
/* * Draw one line of kmsg, and handle wrapping if it won't fit in the screen width. * Return the y-offset of the next line. */static int draw_line_with_wrap(struct drm_scanout_buffer *sb, const struct font_desc *font, struct drm_panic_line *line, int yoffset, u32 fg_color){ int chars_per_row = sb->width / font->width; struct drm_rect r_txt = DRM_RECT_INIT(0, yoffset, sb->width, font->height); struct drm_panic_line line_wrap;
if (line->len > chars_per_row) { line_wrap.len = line->len % chars_per_row; line_wrap.txt = line->txt + line->len - line_wrap.len; draw_txt_rectangle(sb, font, &line_wrap, 1, false, &r_txt, fg_color); r_txt.y1 -= font->height; if (r_txt.y1 < 0) return r_txt.y1; while (line_wrap.txt > line->txt) { line_wrap.txt -= chars_per_row; line_wrap.len = chars_per_row; draw_txt_rectangle(sb, font, &line_wrap, 1, false, &r_txt, fg_color); r_txt.y1 -= font->height; if (r_txt.y1 < 0) return r_txt.y1; } } else { draw_txt_rectangle(sb, font, line, 1, false, &r_txt, fg_color); r_txt.y1 -= font->height; } return r_txt.y1;}
/* * Draw the kmsg buffer to the screen, starting from the youngest message at the bottom, * and going up until reaching the top of the screen. */static void draw_panic_screen_kmsg(struct drm_scanout_buffer *sb){ u32 fg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR, sb->format->format); u32 bg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR, sb->format->format); const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL); struct drm_rect r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height); struct kmsg_dump_iter iter; char kmsg_buf[512]; size_t kmsg_len; struct drm_panic_line line; int yoffset;
if (!font || font->width > sb->width) return;
yoffset = sb->height - font->height - (sb->height % font->height) / 2;
/* Fill with the background color, and draw text on top */ drm_panic_fill(sb, &r_screen, bg_color);
kmsg_dump_rewind(&iter); while (kmsg_dump_get_buffer(&iter, false, kmsg_buf, sizeof(kmsg_buf), &kmsg_len)) { char *start; char *end;
/* ignore terminating NUL and newline */ start = kmsg_buf + kmsg_len - 2; end = kmsg_buf + kmsg_len - 1; while (start > kmsg_buf && yoffset >= 0) { while (start > kmsg_buf && *start != '\n') start--; /* don't count the newline character */ line.txt = start + (start == kmsg_buf ? 0 : 1); line.len = end - line.txt;
yoffset = draw_line_with_wrap(sb, font, &line, yoffset, fg_color); end = start; start--; } }}
#if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)/* * It is unwise to allocate memory in the panic callback, so the buffers are * pre-allocated. Only 2 buffers and the zlib workspace are needed. * Two buffers are enough, using the following buffer usage: * 1) kmsg messages are dumped in buffer1 * 2) kmsg is zlib-compressed into buffer2 * 3) compressed kmsg is encoded as QR-code Numeric stream in buffer1 * 4) QR-code image is generated in buffer2 * The Max QR code size is V40, 177x177, 4071 bytes for image, 2956 bytes for * data segments. * * Typically, ~7500 bytes of kmsg, are compressed into 2800 bytes, which fits in * a V40 QR-code (177x177). * * If CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL is not set, the kmsg data will be put * directly in the QR code. * 1) kmsg messages are dumped in buffer1 * 2) kmsg message is encoded as byte stream in buffer2 * 3) QR-code image is generated in buffer1 */
static uint panic_qr_version = CONFIG_DRM_PANIC_SCREEN_QR_VERSION;module_param(panic_qr_version, uint, 0644);MODULE_PARM_DESC(panic_qr_version, "maximum version (size) of the QR code");
#define MAX_QR_DATA 2956#define MAX_ZLIB_RATIO 3#define QR_BUFFER1_SIZE (MAX_ZLIB_RATIO * MAX_QR_DATA) /* Must also be > 4071 */#define QR_BUFFER2_SIZE 4096#define QR_MARGIN 4 /* 4 modules of foreground color around the qr code */
/* Compression parameters */#define COMPR_LEVEL 6#define WINDOW_BITS 12#define MEM_LEVEL 4
static char *qrbuf1;static char *qrbuf2;static struct z_stream_s stream;
static void __init drm_panic_qr_init(void){ qrbuf1 = kmalloc(QR_BUFFER1_SIZE, GFP_KERNEL); qrbuf2 = kmalloc(QR_BUFFER2_SIZE, GFP_KERNEL); stream.workspace = kmalloc(zlib_deflate_workspacesize(WINDOW_BITS, MEM_LEVEL), GFP_KERNEL);}
static void drm_panic_qr_exit(void){ kfree(qrbuf1); qrbuf1 = NULL; kfree(qrbuf2); qrbuf2 = NULL; kfree(stream.workspace); stream.workspace = NULL;}
static int drm_panic_get_qr_code_url(u8 **qr_image){ struct kmsg_dump_iter iter; char url[256]; size_t kmsg_len, max_kmsg_size; char *kmsg; int max_qr_data_size, url_len;
url_len = snprintf(url, sizeof(url), CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL "?a=%s&v=%s&z=", utsname()->machine, utsname()->release);
max_qr_data_size = drm_panic_qr_max_data_size(panic_qr_version, url_len); max_kmsg_size = min(MAX_ZLIB_RATIO * max_qr_data_size, QR_BUFFER1_SIZE);
/* get kmsg to buffer 1 */ kmsg_dump_rewind(&iter); kmsg_dump_get_buffer(&iter, false, qrbuf1, max_kmsg_size, &kmsg_len);
if (!kmsg_len) return -ENODATA; kmsg = qrbuf1;
try_again: if (zlib_deflateInit2(&stream, COMPR_LEVEL, Z_DEFLATED, WINDOW_BITS, MEM_LEVEL, Z_DEFAULT_STRATEGY) != Z_OK) return -EINVAL;
stream.next_in = kmsg; stream.avail_in = kmsg_len; stream.total_in = 0; stream.next_out = qrbuf2; stream.avail_out = QR_BUFFER2_SIZE; stream.total_out = 0;
if (zlib_deflate(&stream, Z_FINISH) != Z_STREAM_END) return -EINVAL;
if (zlib_deflateEnd(&stream) != Z_OK) return -EINVAL;
if (stream.total_out > max_qr_data_size) { /* too much data for the QR code, so skip the first line and try again */ kmsg = strchr(kmsg, '\n'); if (!kmsg) return -EINVAL; /* skip the first \n */ kmsg += 1; kmsg_len = strlen(kmsg); goto try_again; } *qr_image = qrbuf2;
/* generate qr code image in buffer2 */ return drm_panic_qr_generate(url, qrbuf2, stream.total_out, QR_BUFFER2_SIZE, qrbuf1, QR_BUFFER1_SIZE);}
static int drm_panic_get_qr_code_raw(u8 **qr_image){ struct kmsg_dump_iter iter; size_t kmsg_len; size_t max_kmsg_size = min(drm_panic_qr_max_data_size(panic_qr_version, 0), QR_BUFFER1_SIZE);
kmsg_dump_rewind(&iter); kmsg_dump_get_buffer(&iter, false, qrbuf1, max_kmsg_size, &kmsg_len); if (!kmsg_len) return -ENODATA;
*qr_image = qrbuf1; return drm_panic_qr_generate(NULL, qrbuf1, kmsg_len, QR_BUFFER1_SIZE, qrbuf2, QR_BUFFER2_SIZE);}
static int drm_panic_get_qr_code(u8 **qr_image){ if (strlen(CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL) > 0) return drm_panic_get_qr_code_url(qr_image); else return drm_panic_get_qr_code_raw(qr_image);}
/* * Draw the panic message at the center of the screen, with a QR Code */static int _draw_panic_screen_qr_code(struct drm_scanout_buffer *sb){ u32 fg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR, sb->format->format); u32 bg_color = drm_draw_color_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR, sb->format->format); const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL); struct drm_rect r_screen, r_logo, r_msg, r_qr, r_qr_canvas; unsigned int max_qr_size, scale; unsigned int msg_width, msg_height; int qr_width, qr_canvas_width, qr_pitch, v_margin; u8 *qr_image;
if (!font || !qrbuf1 || !qrbuf2 || !stream.workspace) return -ENOMEM;
r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
drm_panic_logo_rect(&r_logo, font);
msg_width = min(get_max_line_len(panic_msg, panic_msg_lines) * font->width, sb->width); msg_height = min(panic_msg_lines * font->height, sb->height); r_msg = DRM_RECT_INIT(0, 0, msg_width, msg_height);
max_qr_size = min(3 * sb->width / 4, 3 * sb->height / 4);
qr_width = drm_panic_get_qr_code(&qr_image); if (qr_width <= 0) return -ENOSPC;
qr_canvas_width = qr_width + QR_MARGIN * 2; scale = max_qr_size / qr_canvas_width; /* QR code is not readable if not scaled at least by 2 */ if (scale < 2) return -ENOSPC;
pr_debug("QR width %d and scale %d\n", qr_width, scale); r_qr_canvas = DRM_RECT_INIT(0, 0, qr_canvas_width * scale, qr_canvas_width * scale);
v_margin = sb->height - drm_rect_height(&r_qr_canvas) - drm_rect_height(&r_msg); if (v_margin < 0) return -ENOSPC; v_margin /= 5;
drm_rect_translate(&r_qr_canvas, (sb->width - r_qr_canvas.x2) / 2, 2 * v_margin); r_qr = DRM_RECT_INIT(r_qr_canvas.x1 + QR_MARGIN * scale, r_qr_canvas.y1 + QR_MARGIN * scale, qr_width * scale, qr_width * scale);
/* Center the panic message */ drm_rect_translate(&r_msg, (sb->width - r_msg.x2) / 2, 3 * v_margin + drm_rect_height(&r_qr_canvas));
/* Fill with the background color, and draw text on top */ drm_panic_fill(sb, &r_screen, bg_color);
if (!drm_rect_overlap(&r_logo, &r_msg) && !drm_rect_overlap(&r_logo, &r_qr_canvas)) drm_panic_logo_draw(sb, &r_logo, font, fg_color);
draw_txt_rectangle(sb, font, panic_msg, panic_msg_lines, true, &r_msg, fg_color);
/* Draw the qr code */ qr_pitch = DIV_ROUND_UP(qr_width, 8); drm_panic_fill(sb, &r_qr_canvas, fg_color); drm_panic_fill(sb, &r_qr, bg_color); drm_panic_blit(sb, &r_qr, qr_image, qr_pitch, scale, fg_color); return 0;}
static void draw_panic_screen_qr_code(struct drm_scanout_buffer *sb){ if (_draw_panic_screen_qr_code(sb)) draw_panic_screen_user(sb);}#elsestatic void drm_panic_qr_init(void) {};static void drm_panic_qr_exit(void) {};#endif
enum drm_panic_type { DRM_PANIC_TYPE_KMSG, DRM_PANIC_TYPE_USER, DRM_PANIC_TYPE_QR,};
static enum drm_panic_type drm_panic_type = -1;
static const char *drm_panic_type_map[] = { [DRM_PANIC_TYPE_KMSG] = "kmsg", [DRM_PANIC_TYPE_USER] = "user",#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE) [DRM_PANIC_TYPE_QR] = "qr_code",#endif};
static int drm_panic_type_set(const char *val, const struct kernel_param *kp){ unsigned int i;
for (i = 0; i < ARRAY_SIZE(drm_panic_type_map); i++) { if (!strcmp(val, drm_panic_type_map[i])) { drm_panic_type = i; return 0; } }
return -EINVAL;}
static int drm_panic_type_get(char *buffer, const struct kernel_param *kp){ return scnprintf(buffer, PAGE_SIZE, "%s\n", drm_panic_type_map[drm_panic_type]);}
static const struct kernel_param_ops drm_panic_ops = { .set = drm_panic_type_set, .get = drm_panic_type_get,};
module_param_cb(panic_screen, &drm_panic_ops, NULL, 0644);MODULE_PARM_DESC(panic_screen,#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE) "Choose what will be displayed by drm_panic, 'user', 'kmsg' or 'qr_code' [default="#else "Choose what will be displayed by drm_panic, 'user' or 'kmsg' [default="#endif CONFIG_DRM_PANIC_SCREEN "]");
/* * drm_panic_is_format_supported() * @format: a fourcc color code * Returns: true if supported, false otherwise. * * Check if drm_panic will be able to use this color format. */static bool drm_panic_is_format_supported(const struct drm_format_info *format){ if (format->num_planes != 1) return false; return drm_draw_can_convert_from_xrgb8888(format->format);}
static void draw_panic_dispatch(struct drm_scanout_buffer *sb){ switch (drm_panic_type) { case DRM_PANIC_TYPE_KMSG: draw_panic_screen_kmsg(sb); break;
#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE) case DRM_PANIC_TYPE_QR: draw_panic_screen_qr_code(sb); break;#endif
case DRM_PANIC_TYPE_USER: default: draw_panic_screen_user(sb); }}
static void drm_panic_set_description(const char *description){ u32 len;
if (description) { struct drm_panic_line *desc_line = &panic_msg[panic_msg_lines - 1];
desc_line->txt = description; len = strlen(description); /* ignore the last newline character */ if (len && description[len - 1] == '\n') len -= 1; desc_line->len = len; }}
static void drm_panic_clear_description(void){ struct drm_panic_line *desc_line = &panic_msg[panic_msg_lines - 1];
desc_line->len = 0; desc_line->txt = NULL;}
static void draw_panic_plane(struct drm_plane *plane, const char *description){ struct drm_scanout_buffer sb = { }; int ret; unsigned long flags;
if (!drm_panic_trylock(plane->dev, flags)) return;
ret = plane->helper_private->get_scanout_buffer(plane, &sb);
if (ret || !drm_panic_is_format_supported(sb.format)) goto unlock;
/* One of these should be set, or it can't draw pixels */ if (!sb.set_pixel && !sb.pages && iosys_map_is_null(&sb.map[0])) goto unlock;
drm_panic_set_description(description);
draw_panic_dispatch(&sb); if (plane->helper_private->panic_flush) plane->helper_private->panic_flush(plane);
drm_panic_clear_description();
unlock: drm_panic_unlock(plane->dev, flags);}
static struct drm_plane *to_drm_plane(struct kmsg_dumper *kd){ return container_of(kd, struct drm_plane, kmsg_panic);}
static void drm_panic(struct kmsg_dumper *dumper, struct kmsg_dump_detail *detail){ struct drm_plane *plane = to_drm_plane(dumper);
if (detail->reason == KMSG_DUMP_PANIC) draw_panic_plane(plane, detail->description);}
/* * DEBUG FS, This is currently unsafe. * Create one file per plane, so it's possible to debug one plane at a time. * TODO: It would be better to emulate an NMI context. */#ifdef CONFIG_DRM_PANIC_DEBUG#include <linux/debugfs.h>
static ssize_t debugfs_trigger_write(struct file *file, const char __user *user_buf, size_t count, loff_t *ppos){ bool run;
if (kstrtobool_from_user(user_buf, count, &run) == 0 && run) { struct drm_plane *plane = file->private_data;
draw_panic_plane(plane, "Test from debugfs"); } return count;}
static const struct file_operations dbg_drm_panic_ops = { .owner = THIS_MODULE, .write = debugfs_trigger_write, .open = simple_open,};
static void debugfs_register_plane(struct drm_plane *plane, int index){ char fname[32];
snprintf(fname, 32, "drm_panic_plane_%d", index); debugfs_create_file(fname, 0200, plane->dev->debugfs_root, plane, &dbg_drm_panic_ops);}#elsestatic void debugfs_register_plane(struct drm_plane *plane, int index) {}#endif /* CONFIG_DRM_PANIC_DEBUG */
/** * drm_panic_is_enabled * @dev: the drm device that may supports drm_panic * * returns true if the drm device supports drm_panic */bool drm_panic_is_enabled(struct drm_device *dev){ struct drm_plane *plane;
if (!dev->mode_config.num_total_plane) return false;
drm_for_each_plane(plane, dev) if (plane->helper_private && plane->helper_private->get_scanout_buffer) return true; return false;}EXPORT_SYMBOL(drm_panic_is_enabled);
/** * drm_panic_register() - Initialize DRM panic for a device * @dev: the drm device on which the panic screen will be displayed. */void drm_panic_register(struct drm_device *dev){ struct drm_plane *plane; int registered_plane = 0;
if (!dev->mode_config.num_total_plane) return;
drm_for_each_plane(plane, dev) { if (!plane->helper_private || !plane->helper_private->get_scanout_buffer) continue; plane->kmsg_panic.dump = drm_panic; plane->kmsg_panic.max_reason = KMSG_DUMP_PANIC; if (kmsg_dump_register(&plane->kmsg_panic)) drm_warn(dev, "Failed to register panic handler\n"); else { debugfs_register_plane(plane, registered_plane); registered_plane++; } } if (registered_plane) drm_info(dev, "Registered %d planes with drm panic\n", registered_plane);}
/** * drm_panic_unregister() * @dev: the drm device previously registered. */void drm_panic_unregister(struct drm_device *dev){ struct drm_plane *plane;
if (!dev->mode_config.num_total_plane) return;
drm_for_each_plane(plane, dev) { if (!plane->helper_private || !plane->helper_private->get_scanout_buffer) continue; kmsg_dump_unregister(&plane->kmsg_panic); }}
/** * drm_panic_init() - initialize DRM panic. */void __init drm_panic_init(void){ if (drm_panic_type == -1 && drm_panic_type_set(CONFIG_DRM_PANIC_SCREEN, NULL)) { pr_warn("Unsupported value for CONFIG_DRM_PANIC_SCREEN ('%s'), falling back to 'user'...\n", CONFIG_DRM_PANIC_SCREEN); drm_panic_type = DRM_PANIC_TYPE_USER; } drm_panic_qr_init();}
/** * drm_panic_exit() - Free the resources taken by drm_panic_exit() */void drm_panic_exit(void){ drm_panic_qr_exit();}
#ifdef CONFIG_DRM_KUNIT_TEST#include "tests/drm_panic_test.c"#endif