On Wed, Aug 07, 2024 at 03:36:14PM +0200, Jocelyn Falempe wrote:
> Now that kmsg dump callback has the description parameter, use it in
> the user panic screen.
> This is the string passed to panic(), like "VFS: Unable to mount root
> fs on xxx" or "Attempted to kill init! exitcode=0xxxx".
> It gives a hint on why the panic occurred, without being too cryptic.
>
> Signed-off-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
> Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
> ---
>
> v2:
> * Use a macro PANIC_MSG_LINES, instead of directly using the indice in drm_panic_set_description() (Sima)
> * Add drm_panic_clear_description() to make sure the stack allocated pointer won't be used. (Sima)
> * use the macro PANIC_MSG_LINES also in draw_panic_static_user()
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
>
> drivers/gpu/drm/drm_panic.c | 56 ++++++++++++++++++++++++++++---------
> 1 file changed, 43 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
> index 2efede7fa23a..c7d9f3a9e30d 100644
> --- a/drivers/gpu/drm/drm_panic.c
> +++ b/drivers/gpu/drm/drm_panic.c
> @@ -81,7 +81,10 @@ 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 */
> };
> +#define PANIC_MSG_LINES ARRAY_SIZE(panic_msg)
>
> static const struct drm_panic_line logo_ascii[] = {
> PANIC_LINE(" .--. _"),
> @@ -92,6 +95,7 @@ static const struct drm_panic_line logo_ascii[] = {
> PANIC_LINE(" /'\\_ _/`\\ (_)"),
> PANIC_LINE(" \\___)=(___/"),
> };
> +#define PANIC_LOGO_LINES ARRAY_SIZE(logo_ascii)
>
> #if defined(CONFIG_LOGO) && !defined(MODULE)
> static const struct linux_logo *logo_mono;
> @@ -487,13 +491,12 @@ static void draw_txt_rectangle(struct drm_scanout_buffer *sb,
>
> static void draw_panic_static_user(struct drm_scanout_buffer *sb)
> {
> - size_t msg_lines = ARRAY_SIZE(panic_msg);
> - size_t logo_ascii_lines = ARRAY_SIZE(logo_ascii);
> 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;
> unsigned int logo_width, logo_height;
> + unsigned int msg_width, msg_height;
>
> if (!font)
> return;
> @@ -504,14 +507,14 @@ static void draw_panic_static_user(struct drm_scanout_buffer *sb)
> logo_width = logo_mono->width;
> logo_height = logo_mono->height;
> } else {
> - logo_width = get_max_line_len(logo_ascii, logo_ascii_lines) * font->width;
> - logo_height = logo_ascii_lines * font->height;
> + logo_width = get_max_line_len(logo_ascii, PANIC_LOGO_LINES) * font->width;
> + logo_height = PANIC_LOGO_LINES * font->height;
> }
> -
> r_logo = DRM_RECT_INIT(0, 0, logo_width, logo_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));
> +
> + 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);
> @@ -525,10 +528,10 @@ static void draw_panic_static_user(struct drm_scanout_buffer *sb)
> drm_panic_blit(sb, &r_logo, logo_mono->data, DIV_ROUND_UP(logo_width, 8),
> fg_color);
> else
> - draw_txt_rectangle(sb, font, logo_ascii, logo_ascii_lines, false, &r_logo,
> + draw_txt_rectangle(sb, font, logo_ascii, PANIC_LOGO_LINES, false, &r_logo,
> fg_color);
> }
> - draw_txt_rectangle(sb, font, panic_msg, msg_lines, true, &r_msg, fg_color);
> + draw_txt_rectangle(sb, font, panic_msg, PANIC_MSG_LINES, true, &r_msg, fg_color);
> }
>
> /*
> @@ -633,7 +636,31 @@ static void draw_panic_dispatch(struct drm_scanout_buffer *sb)
> }
> }
>
> -static void draw_panic_plane(struct drm_plane *plane)
> +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;
> @@ -642,6 +669,8 @@ static void draw_panic_plane(struct drm_plane *plane)
> if (!drm_panic_trylock(plane->dev, flags))
> return;
>
> + drm_panic_set_description(description);
> +
> ret = plane->helper_private->get_scanout_buffer(plane, &sb);
>
> if (!ret && drm_panic_is_format_supported(sb.format)) {
> @@ -649,6 +678,7 @@ static void draw_panic_plane(struct drm_plane *plane)
> if (plane->helper_private->panic_flush)
> plane->helper_private->panic_flush(plane);
> }
> + drm_panic_clear_description();
> drm_panic_unlock(plane->dev, flags);
> }
>
> @@ -662,7 +692,7 @@ static void drm_panic(struct kmsg_dumper *dumper, struct kmsg_dump_detail *detai
> struct drm_plane *plane = to_drm_plane(dumper);
>
> if (detail->reason == KMSG_DUMP_PANIC)
> - draw_panic_plane(plane);
> + draw_panic_plane(plane, detail->description);
> }
>
>
> @@ -682,7 +712,7 @@ static ssize_t debugfs_trigger_write(struct file *file, const char __user *user_
> if (kstrtobool_from_user(user_buf, count, &run) == 0 && run) {
> struct drm_plane *plane = file->private_data;
>
> - draw_panic_plane(plane);
> + draw_panic_plane(plane, "Test from debugfs");
> }
> return count;
> }
> --
> 2.45.2
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
