diff options
author | Jocelyn Falempe <jfalempe@redhat.com> | 2024-04-09 19:30:41 +0300 |
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committer | Jocelyn Falempe <jfalempe@redhat.com> | 2024-04-15 17:12:49 +0300 |
commit | bf9fb17c6672868d95126321762c8fdfe0ff0a2a (patch) | |
tree | fcca5ea31035eeab52304c6b62b4e3844cef1493 /drivers/gpu/drm/drm_panic.c | |
parent | e2a1cda3e0c784740751d46431973dcee32cf108 (diff) | |
download | linux-bf9fb17c6672868d95126321762c8fdfe0ff0a2a.tar.xz |
drm/panic: Add a drm panic handler
This module displays a user friendly message when a kernel panic
occurs. It currently doesn't contain any debug information,
but that can be added later.
v2
* Use get_scanout_buffer() instead of the drm client API.
(Thomas Zimmermann)
* Add the panic reason to the panic message (Nerdopolis)
* Add an exclamation mark (Nerdopolis)
v3
* Rework the drawing functions, to write the pixels line by line and
to use the drm conversion helper to support other formats.
(Thomas Zimmermann)
v4
* Use drm_fb_r1_to_32bit for fonts (Thomas Zimmermann)
* Remove the default y to DRM_PANIC config option (Thomas Zimmermann)
* Add foreground/background color config option
* Fix the bottom lines not painted if the framebuffer height
is not a multiple of the font height.
* Automatically register the device to drm_panic, if the function
get_scanout_buffer exists. (Thomas Zimmermann)
v5
* Change the drawing API, use drm_fb_blit_from_r1() to draw the font.
* Also add drm_fb_fill() to fill area with background color.
* Add draw_pixel_xy() API for drivers that can't provide a linear buffer.
* Add a flush() callback for drivers that needs to synchronize the buffer.
* Add a void *private field, so drivers can pass private data to
draw_pixel_xy() and flush().
v6
* Fix sparse warning for panic_msg and logo.
v7
* Add select DRM_KMS_HELPER for the color conversion functions.
v8
* Register directly each plane to the panic notifier (Sima)
* Add raw_spinlock to properly handle concurrency (Sima)
* Register plane instead of device, to avoid looping through plane
list, and simplify code.
* Replace get_scanout_buffer() logic with drm_panic_set_buffer()
(Thomas Zimmermann)
* Removed the draw_pixel_xy() API, will see later if it can be added back.
v9
* Revert to using get_scanout_buffer() (Sima)
* Move get_scanout_buffer() and panic_flush() to the plane helper
functions (Thomas Zimmermann)
* Register all planes with get_scanout_buffer() to the panic notifier
* Use drm_panic_lock() to protect against race (Sima)
v10
* Move blit and fill functions back in drm_panic (Thomas Zimmermann).
* Simplify the text drawing functions.
* Use kmsg_dumper instead of panic_notifier (Sima).
v12
* Use array for map and pitch in struct drm_scanout_buffer
to support multi-planar format later. (Thomas Zimmermann)
* Better indent struct drm_scanout_buffer declaration. (Thomas Zimmermann)
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240409163432.352518-3-jfalempe@redhat.com
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Diffstat (limited to 'drivers/gpu/drm/drm_panic.c')
-rw-r--r-- | drivers/gpu/drm/drm_panic.c | 290 |
1 files changed, 290 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c new file mode 100644 index 000000000000..7c81b3d73239 --- /dev/null +++ b/drivers/gpu/drm/drm_panic.c @@ -0,0 +1,290 @@ +// SPDX-License-Identifier: GPL-2.0 or MIT +/* + * Copyright (c) 2023 Red Hat. + * Author: Jocelyn Falempe <jfalempe@redhat.com> + * inspired by the drm_log driver from David Herrmann <dh.herrmann@gmail.com> + * Tux Ascii art taken from cowsay written by Tony Monroe + */ + +#include <linux/font.h> +#include <linux/iosys-map.h> +#include <linux/kdebug.h> +#include <linux/kmsg_dump.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/types.h> + +#include <drm/drm_drv.h> +#include <drm/drm_format_helper.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> + +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."), +}; + +static const struct drm_panic_line logo[] = { + PANIC_LINE(" .--. _"), + PANIC_LINE(" |o_o | | |"), + PANIC_LINE(" |:_/ | | |"), + PANIC_LINE(" // \\ \\ |_|"), + PANIC_LINE(" (| | ) _"), + PANIC_LINE(" /'\\_ _/`\\ (_)"), + PANIC_LINE(" \\___)=(___/"), +}; + +static void drm_panic_fill32(struct iosys_map *map, unsigned int pitch, + unsigned int height, unsigned int width, + u32 color) +{ + unsigned int y, x; + + for (y = 0; y < height; y++) + for (x = 0; x < width; x++) + iosys_map_wr(map, y * pitch + x * sizeof(u32), u32, color); +} + +static void drm_panic_blit32(struct iosys_map *dmap, unsigned int dpitch, + const u8 *sbuf8, unsigned int spitch, + unsigned int height, unsigned int width, + u32 fg32, u32 bg32) +{ + unsigned int y, x; + u32 val32; + + for (y = 0; y < height; y++) { + for (x = 0; x < width; x++) { + val32 = (sbuf8[(y * spitch) + x / 8] & (0x80 >> (x % 8))) ? fg32 : bg32; + iosys_map_wr(dmap, y * dpitch + x * sizeof(u32), u32, val32); + } + } +} + +static const u8 *get_char_bitmap(const struct font_desc *font, char c, size_t font_pitch) +{ + return font->data + (c * font->height) * font_pitch; +} + +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 fg_color, + u32 bg_color) +{ + int i, j; + const u8 *src; + size_t font_pitch = DIV_ROUND_UP(font->width, 8); + struct iosys_map dst; + unsigned int px_width = sb->format->cpp[0]; + int left = 0; + + 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); + + if (centered) + left = (drm_rect_width(clip) - (line_len * font->width)) / 2; + + dst = sb->map[0]; + iosys_map_incr(&dst, (clip->y1 + i * font->height) * sb->pitch[0] + + (clip->x1 + left) * px_width); + for (j = 0; j < line_len; j++) { + src = get_char_bitmap(font, msg[i].txt[j], font_pitch); + drm_panic_blit32(&dst, sb->pitch[0], src, font_pitch, + font->height, font->width, + fg_color, bg_color); + iosys_map_incr(&dst, font->width * px_width); + } + } +} + +/* + * Draw the panic message at the center of the screen + */ +static void draw_panic_static(struct drm_scanout_buffer *sb) +{ + size_t msg_lines = ARRAY_SIZE(panic_msg); + size_t logo_lines = ARRAY_SIZE(logo); + u32 fg_color = CONFIG_DRM_PANIC_FOREGROUND_COLOR; + u32 bg_color = CONFIG_DRM_PANIC_BACKGROUND_COLOR; + const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL); + struct drm_rect r_logo, r_msg; + + if (!font) + return; + + r_logo = DRM_RECT_INIT(0, 0, + get_max_line_len(logo, logo_lines) * font->width, + logo_lines * font->height); + r_msg = DRM_RECT_INIT(0, 0, + min(get_max_line_len(panic_msg, msg_lines) * font->width, sb->width), + min(msg_lines * font->height, sb->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_fill32(&sb->map[0], sb->pitch[0], sb->height, sb->width, bg_color); + + if ((r_msg.x1 >= drm_rect_width(&r_logo) || r_msg.y1 >= drm_rect_height(&r_logo)) && + drm_rect_width(&r_logo) < sb->width && drm_rect_height(&r_logo) < sb->height) { + draw_txt_rectangle(sb, font, logo, logo_lines, false, &r_logo, fg_color, bg_color); + } + draw_txt_rectangle(sb, font, panic_msg, msg_lines, true, &r_msg, fg_color, bg_color); +} + +/* + * 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 format->format == DRM_FORMAT_XRGB8888; +} + +static void draw_panic_plane(struct drm_plane *plane) +{ + 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)) { + draw_panic_static(&sb); + if (plane->helper_private->panic_flush) + plane->helper_private->panic_flush(plane); + } + 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, enum kmsg_dump_reason reason) +{ + struct drm_plane *plane = to_drm_plane(dumper); + + if (reason == KMSG_DUMP_PANIC) + draw_panic_plane(plane); +} + +/** + * 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 + registered_plane++; + } + if (registered_plane) + drm_info(dev, "Registered %d planes with drm panic\n", registered_plane); +} +EXPORT_SYMBOL(drm_panic_register); + +/** + * 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); + } +} +EXPORT_SYMBOL(drm_panic_unregister); |