// SPDX-License-Identifier: GPL-2.0 or MIT /* * Copyright (c) 2023 Red Hat. * Author: Jocelyn Falempe <[email protected]> * inspired by the drm_log driver from David Herrmann <[email protected]> * Tux Ascii art taken from cowsay written by Tony Monroe */ #include <linux/font.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" MODULE_AUTHOR(…) …; MODULE_DESCRIPTION(…) …; MODULE_LICENSE(…) …; static char drm_panic_screen[16] = …; module_param_string(…); MODULE_PARM_DESC(…) …; /** * 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 { … }; #define PANIC_LINE(s) … static struct drm_panic_line panic_msg[] = …; static const size_t panic_msg_lines = …; static const struct drm_panic_line logo_ascii[] = …; static const size_t logo_ascii_lines = …; #if defined(CONFIG_LOGO) && !defined(MODULE) static const struct linux_logo *logo_mono; static int drm_panic_setup_logo(void) { … } device_initcall(drm_panic_setup_logo); #else #define logo_mono … #endif /* * Color conversion */ static u16 convert_xrgb8888_to_rgb565(u32 pix) { … } static u16 convert_xrgb8888_to_rgba5551(u32 pix) { … } static u16 convert_xrgb8888_to_xrgb1555(u32 pix) { … } static u16 convert_xrgb8888_to_argb1555(u32 pix) { … } static u32 convert_xrgb8888_to_argb8888(u32 pix) { … } static u32 convert_xrgb8888_to_xbgr8888(u32 pix) { … } static u32 convert_xrgb8888_to_abgr8888(u32 pix) { … } static u32 convert_xrgb8888_to_xrgb2101010(u32 pix) { … } static u32 convert_xrgb8888_to_argb2101010(u32 pix) { … } /* * convert_from_xrgb8888 - convert one pixel from xrgb8888 to the desired format * @color: input color, in xrgb8888 format * @format: output format * * Returns: * Color in the format specified, casted to u32. * Or 0 if the format is not supported. */ static u32 convert_from_xrgb8888(u32 color, u32 format) { … } /* * Blit & Fill */ /* check if the pixel at coord x,y is 1 (foreground) or 0 (background) */ static bool drm_panic_is_pixel_fg(const u8 *sbuf8, unsigned int spitch, int x, int y) { … } static void drm_panic_blit16(struct iosys_map *dmap, unsigned int dpitch, const u8 *sbuf8, unsigned int spitch, unsigned int height, unsigned int width, unsigned int scale, u16 fg16) { … } static void drm_panic_blit24(struct iosys_map *dmap, unsigned int dpitch, const u8 *sbuf8, unsigned int spitch, unsigned int height, unsigned int width, unsigned int scale, u32 fg32) { … } static void drm_panic_blit32(struct iosys_map *dmap, unsigned int dpitch, const u8 *sbuf8, unsigned int spitch, unsigned int height, unsigned int width, unsigned int scale, u32 fg32) { … } 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) { … } /* * 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) { … } static void drm_panic_fill16(struct iosys_map *dmap, unsigned int dpitch, unsigned int height, unsigned int width, u16 color) { … } static void drm_panic_fill24(struct iosys_map *dmap, unsigned int dpitch, unsigned int height, unsigned int width, u32 color) { … } static void drm_panic_fill32(struct iosys_map *dmap, unsigned int dpitch, unsigned int height, unsigned int width, u32 color) { … } static void drm_panic_fill_pixel(struct drm_scanout_buffer *sb, struct drm_rect *clip, u32 color) { … } /* * 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) { … } static const u8 *get_char_bitmap(const struct font_desc *font, char c, size_t font_pitch) { … } static unsigned int get_max_line_len(const struct drm_panic_line *lines, int len) { … } /* * 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) { … } static void drm_panic_logo_rect(struct drm_rect *rect, const struct font_desc *font) { … } static void drm_panic_logo_draw(struct drm_scanout_buffer *sb, struct drm_rect *rect, const struct font_desc *font, u32 fg_color) { … } static void draw_panic_static_user(struct drm_scanout_buffer *sb) { … } /* * 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) { … } /* * 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_static_kmsg(struct drm_scanout_buffer *sb) { … } #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 … #define MAX_ZLIB_RATIO … #define QR_BUFFER1_SIZE … #define QR_BUFFER2_SIZE … #define QR_MARGIN … /* Compression parameters */ #define COMPR_LEVEL … #define WINDOW_BITS … #define MEM_LEVEL … 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; } extern size_t drm_panic_qr_max_data_size(u8 version, size_t url_len); extern u8 drm_panic_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size, u8 *tmp, size_t tmp_size); 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&zl=", 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_static_qr_code(struct drm_scanout_buffer *sb) { u32 fg_color = convert_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR, sb->format->format); u32 bg_color = convert_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)) / 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)) 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_static_qr_code(struct drm_scanout_buffer *sb) { if (_draw_panic_static_qr_code(sb)) draw_panic_static_user(sb); } #else static void draw_panic_static_qr_code(struct drm_scanout_buffer *sb) { … } static void drm_panic_qr_init(void) {}; static void drm_panic_qr_exit(void) {}; #endif /* * 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) { … } static void draw_panic_dispatch(struct drm_scanout_buffer *sb) { … } static void drm_panic_set_description(const char *description) { … } static void drm_panic_clear_description(void) { … } static void draw_panic_plane(struct drm_plane *plane, const char *description) { … } static struct drm_plane *to_drm_plane(struct kmsg_dumper *kd) { … } static void drm_panic(struct kmsg_dumper *dumper, struct kmsg_dump_detail *detail) { … } /* * 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) { … } static const struct file_operations dbg_drm_panic_ops = …; static void debugfs_register_plane(struct drm_plane *plane, int index) { … } #else static 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) { … } EXPORT_SYMBOL(…); /** * 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) { … } /** * drm_panic_unregister() * @dev: the drm device previously registered. */ void drm_panic_unregister(struct drm_device *dev) { … } /** * drm_panic_init() - initialize DRM panic. */ void __init drm_panic_init(void) { … } /** * drm_panic_exit() - Free the resources taken by drm_panic_exit() */ void drm_panic_exit(void) { … }
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