Re: [PATCH v3 13/14] drm/panic: Move panic display code into helper library

[Jocelyn Falempe <jfalempe@redhat.com>]

On 9/2/26 14:13, Thomas Zimmermann wrote:
> Move drm_plane_helper_display_panic_screen() and the existing panic-
> display code into drm_panic_helper.c. Rename symbols accordingly.
> Also update the QR-related code and the bindings accordingly.
> 
> Link the rsp. object file into drm_kms_helper.ko. Eventually the code
> will become a DRM drawing library, together with DRM's format and draw
> helpers. This requires more preparation. until then, KMS helpers serve
> as a module. All DRM drivers link it anyway.
> 
> Add a new section about drawing helpers to the documentation of the KMS
> helpers. List format and panic helpers there.

Thanks, it looks good to me.

Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>

> 
> v2:
> - fix dependencies on other DRM modules (Randy, Sashiko)
> - provide placeholders for drm_panic_helper_{init,exit}() (Sashiko)
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>   Documentation/gpu/drm-kms-helpers.rst         |  11 +-
>   MAINTAINERS                                   |   5 +-
>   drivers/gpu/drm/Kconfig                       |   9 +-
>   drivers/gpu/drm/Makefile                      |   3 +-
>   drivers/gpu/drm/drm_crtc_internal.h           |   2 -
>   drivers/gpu/drm/drm_drv.c                     |   1 -
>   drivers/gpu/drm/drm_kms_helper_common.c       |  14 +
>   drivers/gpu/drm/drm_panic.c                   | 894 -----------------
>   drivers/gpu/drm/drm_panic_helper.c            | 916 ++++++++++++++++++
>   ...drm_panic_qr.rs => drm_panic_helper_qr.rs} |   4 +-
>   drivers/gpu/drm/drm_panic_internal.h          |  14 +
>   ...m_panic_test.c => drm_panic_helper_test.c} |  24 +-
>   include/drm/drm_panic.h                       |   7 -
>   include/drm/drm_panic_helper.h                |   5 +
>   rust/bindings/bindings_helper.h               |   4 +-
>   15 files changed, 987 insertions(+), 926 deletions(-)
>   create mode 100644 drivers/gpu/drm/drm_panic_helper.c
>   rename drivers/gpu/drm/{drm_panic_qr.rs => drm_panic_helper_qr.rs} (99%)
>   rename drivers/gpu/drm/tests/{drm_panic_test.c => drm_panic_helper_test.c} (88%)
> 
> diff --git a/Documentation/gpu/drm-kms-helpers.rst b/Documentation/gpu/drm-kms-helpers.rst
> index 94cfc26acecc..400cd0112713 100644
> --- a/Documentation/gpu/drm-kms-helpers.rst
> +++ b/Documentation/gpu/drm-kms-helpers.rst
> @@ -118,12 +118,21 @@ fbdev Helper Functions Reference
>   .. kernel-doc:: drivers/gpu/drm/drm_fb_helper.c
>      :export:
>   
> -format Helper Functions Reference
> +Draw Helper Functions Reference
>   =================================
>   
> +Format-Conversion Helper Reference
> +----------------------------------
> +
>   .. kernel-doc:: drivers/gpu/drm/drm_format_helper.c
>      :export:
>   
> +Panic Helper Reference
> +----------------------
> +
> +.. kernel-doc:: drivers/gpu/drm/drm_panic_helper.c
> +   :export:
> +
>   Framebuffer DMA Helper Functions Reference
>   ==========================================
>   
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ccc5dc0a01ae..3c41e2730a37 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9112,8 +9112,9 @@ T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
>   F:	drivers/gpu/drm/drm_draw.c
>   F:	drivers/gpu/drm/drm_draw_internal.h
>   F:	drivers/gpu/drm/drm_panic.c
> +F:	drivers/gpu/drm/drm_panic_helper.c
>   F:	drivers/gpu/drm/drm_panic_internal.h
> -F:	drivers/gpu/drm/tests/drm_panic_test.c
> +F:	drivers/gpu/drm/tests/drm_panic_helper_test.c
>   F:	include/drm/drm_panic.h
>   F:	include/drm/drm_panic_helper.h
>   
> @@ -9124,7 +9125,7 @@ L:	dri-devel@lists.freedesktop.org
>   L:	rust-for-linux@vger.kernel.org
>   S:	Supported
>   T:	git https://gitlab.freedesktop.org/drm/misc/kernel.git
> -F:	drivers/gpu/drm/drm_panic_qr.rs
> +F:	drivers/gpu/drm/drm_panic_helper_qr.rs
>   
>   DRM PRIVACY-SCREEN CLASS
>   M:	Hans de Goede <hansg@kernel.org>
> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> index 323422861e8f..65d46dfa7266 100644
> --- a/drivers/gpu/drm/Kconfig
> +++ b/drivers/gpu/drm/Kconfig
> @@ -45,6 +45,7 @@ config DRM_MIPI_DSI
>   config DRM_KMS_HELPER
>   	tristate
>   	depends on DRM
> +	select DRM_PANIC_HELPER if DRM_PANIC
>   	select FB_CORE if DRM_FBDEV_EMULATION
>   	help
>   	  CRTC helpers for KMS drivers.
> @@ -56,8 +57,6 @@ config DRM_DRAW
>   config DRM_PANIC
>   	bool "Display a user-friendly message when a kernel panic occurs"
>   	depends on DRM && PRINTK
> -	select FONT_SUPPORT
> -	select DRM_DRAW
>   	help
>   	  Enable a drm panic handler, which will display a user-friendly message
>   	  when a kernel panic occurs. It's useful when using a user-space
> @@ -130,6 +129,12 @@ config DRM_PANIC_SCREEN_QR_VERSION
>   	  Smaller QR code are easier to read, but will contain less debugging
>   	  data. Default is 40.
>   
> +config DRM_PANIC_HELPER
> +	bool
> +	depends on DRM
> +	select DRM_DRAW
> +	select FONT_SUPPORT
> +
>   config DRM_RAS
>   	bool "DRM RAS support"
>   	depends on DRM
> diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> index e635fcffd379..f0c340aa2ec6 100644
> --- a/drivers/gpu/drm/Makefile
> +++ b/drivers/gpu/drm/Makefile
> @@ -92,7 +92,6 @@ drm-$(CONFIG_DRM_PRIVACY_SCREEN) += \
>   drm-$(CONFIG_DRM_ACCEL) += ../../accel/drm_accel.o
>   drm-$(CONFIG_DRM_PANIC) += drm_panic.o
>   drm-$(CONFIG_DRM_DRAW) += drm_draw.o
> -drm-$(CONFIG_DRM_PANIC_SCREEN_QR_CODE) += drm_panic_qr.o
>   drm-$(CONFIG_DRM_RAS) += drm_ras.o drm_ras_nl.o drm_ras_genl_family.o
>   obj-$(CONFIG_DRM)	+= drm.o
>   
> @@ -157,6 +156,8 @@ drm_kms_helper-y := \
>   	drm_simple_kms_helper.o \
>   	drm_vblank_helper.o
>   drm_kms_helper-$(CONFIG_DRM_PANEL_BRIDGE) += bridge/panel.o
> +drm_kms_helper-$(CONFIG_DRM_PANIC_HELPER) += drm_panic_helper.o
> +drm_kms_helper-$(CONFIG_DRM_PANIC_SCREEN_QR_CODE) += drm_panic_helper_qr.o
>   drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
>   obj-$(CONFIG_DRM_KMS_HELPER) += drm_kms_helper.o
>   
> diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
> index 83146ffef00c..3492787c3697 100644
> --- a/drivers/gpu/drm/drm_crtc_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_internal.h
> @@ -322,13 +322,11 @@ bool drm_panic_is_enabled(struct drm_device *dev);
>   void drm_panic_register(struct drm_device *dev);
>   void drm_panic_unregister(struct drm_device *dev);
>   void drm_panic_init(void);
> -void drm_panic_exit(void);
>   #else
>   static inline bool drm_panic_is_enabled(struct drm_device *dev) { return false; }
>   static inline void drm_panic_register(struct drm_device *dev) {}
>   static inline void drm_panic_unregister(struct drm_device *dev) {}
>   static inline void drm_panic_init(void) {}
> -static inline void drm_panic_exit(void) {}
>   #endif
>   
>   #endif /* __DRM_CRTC_INTERNAL_H__ */
> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
> index 64055514acbf..0cdc606af8d1 100644
> --- a/drivers/gpu/drm/drm_drv.c
> +++ b/drivers/gpu/drm/drm_drv.c
> @@ -1255,7 +1255,6 @@ static void drm_core_exit(void)
>   {
>   	drm_ras_genl_family_unregister();
>   	drm_privacy_screen_lookup_exit();
> -	drm_panic_exit();
>   	accel_core_exit();
>   	unregister_chrdev(DRM_MAJOR, "drm");
>   	drm_debugfs_remove_root();
> diff --git a/drivers/gpu/drm/drm_kms_helper_common.c b/drivers/gpu/drm/drm_kms_helper_common.c
> index 0c7550c0462b..b5d5b469b444 100644
> --- a/drivers/gpu/drm/drm_kms_helper_common.c
> +++ b/drivers/gpu/drm/drm_kms_helper_common.c
> @@ -27,6 +27,20 @@
>   
>   #include <linux/module.h>
>   
> +#include "drm_panic_internal.h"
> +
> +static int __init drm_kms_helper_init(void)
> +{
> +	return drm_panic_helper_init();
> +}
> +module_init(drm_kms_helper_init);
> +
> +static void __exit drm_kms_helper_exit(void)
> +{
> +	drm_panic_helper_exit();
> +}
> +module_exit(drm_kms_helper_exit);
> +
>   MODULE_AUTHOR("David Airlie, Jesse Barnes");
>   MODULE_DESCRIPTION("DRM KMS helper");
>   MODULE_LICENSE("GPL and additional rights");
> diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
> index 41ba0c4b050e..a1e80449a990 100644
> --- a/drivers/gpu/drm/drm_panic.c
> +++ b/drivers/gpu/drm/drm_panic.c
> @@ -7,34 +7,22 @@
>    */
>   
>   #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_panic_helper.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"
>   #include "drm_panic_internal.h"
>   
>   MODULE_AUTHOR("Jocelyn Falempe");
> @@ -58,751 +46,10 @@ MODULE_LICENSE("GPL");
>    * drm_plane_helper_display_panic_screen() for a generic implementation.
>    */
>   
> -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);
> -	if (!vaddr2)
> -		return;
> -
> -	*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 = font_data_glyph_buf(font->data, font->width, font->height,
> -						  (unsigned char)msg[i].txt[j]);
> -			rec.x2 = rec.x1 + font->width;
> -			if (src)
> -				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 int draw_panic_screen_user(struct drm_scanout_buffer *sb, u32 fg_color, u32 bg_color)
> -{
> -	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 || font->width > sb->width)
> -		return -EINVAL;
> -
> -	fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);
> -	bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
> -
> -	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);
> -
> -	return 0;
> -}
> -
> -/*
> - * 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 int draw_panic_screen_kmsg(struct drm_scanout_buffer *sb, u32 fg_color, u32 bg_color)
> -{
> -	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 -EINVAL;
> -
> -	fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);
> -	bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
> -
> -	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--;
> -		}
> -	}
> -
> -	return 0;
> -}
> -
>   #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, unsigned int qr_version)
> -{
> -	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), "%s?a=%s&v=%s&z=",
> -			   CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL,
> -			   utsname()->machine, utsname()->release);
> -
> -	max_qr_data_size = drm_panic_qr_max_data_size(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, unsigned int qr_version)
> -{
> -	struct kmsg_dump_iter iter;
> -	size_t kmsg_len;
> -	size_t max_kmsg_size = min(drm_panic_qr_max_data_size(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, unsigned int qr_version)
> -{
> -	if (strlen(CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL) > 0)
> -		return drm_panic_get_qr_code_url(qr_image, qr_version);
> -	else
> -		return drm_panic_get_qr_code_raw(qr_image, qr_version);
> -}
> -
> -/*
> - * 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, u32 bg_color,
> -				     unsigned int qr_version)
> -{
> -	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 (!qrbuf1 || !qrbuf2 || !stream.workspace)
> -		return -ENOMEM;
> -	if (!font)
> -		return -EINVAL;
> -
> -	fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);
> -	bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
> -
> -	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, qr_version);
> -	if (qr_width < 0)
> -		return qr_width;
> -	else if (!qr_width)
> -		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;
> -}
> -#else
> -static void drm_panic_qr_init(void) {};
> -static void drm_panic_qr_exit(void) {};
>   #endif
>   
>   static enum drm_panic_type drm_panic_type = -1;
> @@ -849,134 +96,6 @@ MODULE_PARM_DESC(panic_screen,
>   #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 int draw_panic_dispatch(struct drm_scanout_buffer *sb, enum drm_panic_type panic_type,
> -			       u32 fg_color, u32 bg_color, unsigned int qr_version)
> -{
> -	int ret;
> -
> -retry:
> -	switch (panic_type) {
> -	case DRM_PANIC_TYPE_KMSG:
> -		ret = draw_panic_screen_kmsg(sb, fg_color, bg_color);
> -		if (ret) {
> -			panic_type = DRM_PANIC_TYPE_USER;
> -			goto retry;
> -		}
> -		break;
> -#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> -	case DRM_PANIC_TYPE_QR:
> -		ret = draw_panic_screen_qr_code(sb, fg_color, bg_color, qr_version);
> -		if (ret) {
> -			panic_type = DRM_PANIC_TYPE_USER;
> -			goto retry;
> -		}
> -		break;
> -#endif
> -	case DRM_PANIC_TYPE_USER:
> -	default:
> -		ret = draw_panic_screen_user(sb, fg_color, bg_color);
> -	}
> -
> -	return ret;
> -}
> -
> -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;
> -}
> -
> -/**
> - * drm_plane_helper_display_panic_screen - Displays a panic screen according to the given settings
> - * @plane: the DRM plane to display to
> - * @description: error message to display
> - * @panic_type: type of panic screen
> - * @fg_color: text foreground color
> - * @bg_color: text background color
> - * @qr_version: version of the QR code, if any
> - *
> - * This helper display a panic screen on common primary planes. The panic
> - * screen can either display a kernel message, a user message or a QR code.
> - *
> - * The helper uses struct drm_plane_helper_funcs.get_scanout_buffer, where
> - * the plane can provide a scanout buffer that the panic handler can draw to.
> - * Currently only linear buffer and a few color formats are supported.
> - *
> - * Optionally the plane can also provide a &drm_plane_helper_funcs.panic_flush
> - * callback, which the DRM panic handler calls after drawing to send additional
> - * commands to the hardware to make the scanout buffer visible.
> - *
> - * Returns:
> - * 0 on success, or a negative errno code otherwise
> - */
> -int drm_plane_helper_display_panic_screen(struct drm_plane *plane, const char *description,
> -					  enum drm_panic_type panic_type,
> -					  u32 fg_color, u32 bg_color, unsigned int qr_version)
> -{
> -	struct drm_scanout_buffer sb = { };
> -	int ret;
> -
> -	ret = plane->helper_private->get_scanout_buffer(plane, &sb);
> -	if (ret)
> -		return ret;
> -
> -	if (!drm_panic_is_format_supported(sb.format))
> -		return -EINVAL;
> -
> -	/* 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]))
> -		return -EINVAL;
> -
> -	drm_panic_set_description(description);
> -
> -	ret = draw_panic_dispatch(&sb, panic_type, fg_color, bg_color, qr_version);
> -	if (!ret) {
> -		/*
> -		 * Only flush if we have a panic screen to display. Otherwise
> -		 * it's probably better to leave the display output as-is.
> -		 */
> -		if (plane->helper_private->panic_flush)
> -			plane->helper_private->panic_flush(plane);
> -	}
> -
> -	drm_panic_clear_description();
> -
> -	return ret;
> -}
> -EXPORT_SYMBOL(drm_plane_helper_display_panic_screen);
> -
>   #define drm_panic_trylock(dev, flags) \
>   	raw_spin_trylock_irqsave(&(dev)->mode_config.panic_lock, flags)
>   
> @@ -1143,17 +262,4 @@ void __init drm_panic_init(void)
>   			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
> diff --git a/drivers/gpu/drm/drm_panic_helper.c b/drivers/gpu/drm/drm_panic_helper.c
> new file mode 100644
> index 000000000000..f64a3ca38467
> --- /dev/null
> +++ b/drivers/gpu/drm/drm_panic_helper.c
> @@ -0,0 +1,916 @@
> +// SPDX-License-Identifier: GPL-2.0 or MIT
> +
> +#include <linux/export.h>
> +#include <linux/font.h>
> +#include <linux/highmem.h>
> +#include <linux/iosys-map.h>
> +#include <linux/linux_logo.h>
> +#include <linux/utsname.h>
> +#include <linux/zlib.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_panic_helper.h>
> +#include <drm/drm_plane.h>
> +#include <drm/drm_rect.h>
> +
> +#include "drm_draw_internal.h"
> +#include "drm_panic_internal.h"
> +
> +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 __init drm_panic_helper_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;
> +}
> +#else
> +#define logo_mono	((const struct linux_logo *)NULL)
> +static int __init drm_panic_helper_setup_logo(void)
> +{
> +	return 0;
> +}
> +#endif
> +
> +/*
> + *  Blit & Fill functions
> + */
> +static void drm_panic_helper_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_helper_write_pixel16(void *vaddr, unsigned int offset, u16 color)
> +{
> +	u16 *p = vaddr + offset;
> +
> +	*p = color;
> +}
> +
> +static void drm_panic_helper_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_helper_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);
> +	if (!vaddr2)
> +		return;
> +
> +	*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_helper_write_pixel32(void *vaddr, unsigned int offset, u32 color)
> +{
> +	u32 *p = vaddr + offset;
> +
> +	*p = color;
> +}
> +
> +static void drm_panic_helper_write_pixel(void *vaddr, unsigned int offset, u32 color,
> +					 unsigned int cpp)
> +{
> +	switch (cpp) {
> +	case 2:
> +		drm_panic_helper_write_pixel16(vaddr, offset, color);
> +		break;
> +	case 3:
> +		drm_panic_helper_write_pixel24(vaddr, offset, color);
> +		break;
> +	case 4:
> +		drm_panic_helper_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_helper_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_helper_write_pixel24_xpage(vaddr,
> +									     pages[page + 1],
> +									     offset, fg32);
> +				else
> +					drm_panic_helper_write_pixel(vaddr, offset, fg32, cpp);
> +			}
> +		}
> +	}
> +	if (vaddr)
> +		kunmap_local(vaddr);
> +}
> +
> +/*
> + * drm_panic_helper_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_helper_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_helper_blit_pixel(sb, clip, sbuf8, spitch, scale, fg_color);
> +
> +	if (sb->pages)
> +		return drm_panic_helper_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_helper_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_helper_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_helper_write_pixel24_xpage(vaddr, pages[page + 1],
> +								     offset, color);
> +			else
> +				drm_panic_helper_write_pixel(vaddr, offset, color, cpp);
> +		}
> +	}
> +	if (vaddr)
> +		kunmap_local(vaddr);
> +}
> +
> +/*
> + * drm_panic_helper_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_helper_fill(struct drm_scanout_buffer *sb, struct drm_rect *clip,
> +				  u32 color)
> +{
> +	struct iosys_map map;
> +
> +	if (sb->set_pixel)
> +		return drm_panic_helper_fill_pixel(sb, clip, color);
> +
> +	if (sb->pages)
> +		return drm_panic_helper_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 = font_data_glyph_buf(font->data, font->width, font->height,
> +						  (unsigned char)msg[i].txt[j]);
> +			rec.x2 = rec.x1 + font->width;
> +			if (src)
> +				drm_panic_helper_blit(sb, &rec, src, font_pitch, 1, color);
> +			rec.x1 += font->width;
> +		}
> +	}
> +}
> +
> +static void drm_panic_helper_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_helper_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_helper_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 int drm_panic_helper_draw_screen_user(struct drm_scanout_buffer *sb,
> +					     u32 fg_color, u32 bg_color)
> +{
> +	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 || font->width > sb->width)
> +		return -EINVAL;
> +
> +	fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);
> +	bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
> +
> +	r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
> +	drm_panic_helper_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_helper_fill(sb, &r_screen, bg_color);
> +
> +	if (!drm_rect_overlap(&r_logo, &r_msg))
> +		drm_panic_helper_logo_draw(sb, &r_logo, font, fg_color);
> +
> +	draw_txt_rectangle(sb, font, panic_msg, panic_msg_lines, true, &r_msg, fg_color);
> +
> +	return 0;
> +}
> +
> +/*
> + * 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 int drm_panic_helper_draw_screen_kmsg(struct drm_scanout_buffer *sb,
> +					     u32 fg_color, u32 bg_color)
> +{
> +	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 -EINVAL;
> +
> +	fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);
> +	bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
> +
> +	yoffset = sb->height - font->height - (sb->height % font->height) / 2;
> +
> +	/* Fill with the background color, and draw text on top */
> +	drm_panic_helper_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--;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +#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
> + */
> +
> +#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_helper_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_helper_qr_exit(void)
> +{
> +	kfree(qrbuf1);
> +	qrbuf1 = NULL;
> +	kfree(qrbuf2);
> +	qrbuf2 = NULL;
> +	kfree(stream.workspace);
> +	stream.workspace = NULL;
> +}
> +
> +static int drm_panic_helper_get_qr_code_url(u8 **qr_image, unsigned int qr_version)
> +{
> +	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), "%s?a=%s&v=%s&z=",
> +			   CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL,
> +			   utsname()->machine, utsname()->release);
> +
> +	max_qr_data_size = drm_panic_helper_qr_max_data_size(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_helper_qr_generate(url, qrbuf2, stream.total_out, QR_BUFFER2_SIZE,
> +					    qrbuf1, QR_BUFFER1_SIZE);
> +}
> +
> +static int drm_panic_helper_get_qr_code_raw(u8 **qr_image, unsigned int qr_version)
> +{
> +	struct kmsg_dump_iter iter;
> +	size_t kmsg_len;
> +	size_t max_kmsg_size = min(drm_panic_helper_qr_max_data_size(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_helper_qr_generate(NULL, qrbuf1, kmsg_len, QR_BUFFER1_SIZE,
> +					    qrbuf2, QR_BUFFER2_SIZE);
> +}
> +
> +static int drm_panic_helper_get_qr_code(u8 **qr_image, unsigned int qr_version)
> +{
> +	if (strlen(CONFIG_DRM_PANIC_SCREEN_QR_CODE_URL) > 0)
> +		return drm_panic_helper_get_qr_code_url(qr_image, qr_version);
> +	else
> +		return drm_panic_helper_get_qr_code_raw(qr_image, qr_version);
> +}
> +
> +/*
> + * Draw the panic message at the center of the screen, with a QR Code
> + */
> +static int drm_panic_helper_draw_screen_qr_code(struct drm_scanout_buffer *sb,
> +						u32 fg_color, u32 bg_color,
> +						unsigned int qr_version)
> +{
> +	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 (!qrbuf1 || !qrbuf2 || !stream.workspace)
> +		return -ENOMEM;
> +	if (!font)
> +		return -EINVAL;
> +
> +	fg_color = drm_draw_color_from_xrgb8888(fg_color, sb->format->format);
> +	bg_color = drm_draw_color_from_xrgb8888(bg_color, sb->format->format);
> +
> +	r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
> +
> +	drm_panic_helper_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_helper_get_qr_code(&qr_image, qr_version);
> +	if (qr_width < 0)
> +		return qr_width;
> +	else if (!qr_width)
> +		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_helper_fill(sb, &r_screen, bg_color);
> +
> +	if (!drm_rect_overlap(&r_logo, &r_msg) && !drm_rect_overlap(&r_logo, &r_qr_canvas))
> +		drm_panic_helper_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_helper_fill(sb, &r_qr_canvas, fg_color);
> +	drm_panic_helper_fill(sb, &r_qr, bg_color);
> +	drm_panic_helper_blit(sb, &r_qr, qr_image, qr_pitch, scale, fg_color);
> +	return 0;
> +}
> +#else
> +static void __init drm_panic_helper_qr_init(void) { };
> +static void __exit drm_panic_helper_qr_exit(void) { };
> +#endif
> +
> +/*
> + * drm_panic_helper_format_is_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_helper_format_is_supported(const struct drm_format_info *format)
> +{
> +	if (format->num_planes != 1)
> +		return false;
> +	return drm_draw_can_convert_from_xrgb8888(format->format);
> +}
> +
> +static int draw_panic_helper_dispatch(struct drm_scanout_buffer *sb,
> +				      enum drm_panic_type panic_type,
> +				      u32 fg_color, u32 bg_color,
> +				      unsigned int qr_version)
> +{
> +	int ret;
> +
> +retry:
> +	switch (panic_type) {
> +	case DRM_PANIC_TYPE_KMSG:
> +		ret = drm_panic_helper_draw_screen_kmsg(sb, fg_color, bg_color);
> +		if (ret) {
> +			panic_type = DRM_PANIC_TYPE_USER;
> +			goto retry;
> +		}
> +		break;
> +#if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> +	case DRM_PANIC_TYPE_QR:
> +		ret = drm_panic_helper_draw_screen_qr_code(sb, fg_color, bg_color, qr_version);
> +		if (ret) {
> +			panic_type = DRM_PANIC_TYPE_USER;
> +			goto retry;
> +		}
> +		break;
> +#endif
> +	case DRM_PANIC_TYPE_USER:
> +	default:
> +		ret = drm_panic_helper_draw_screen_user(sb, fg_color, bg_color);
> +	}
> +
> +	return ret;
> +}
> +
> +static void drm_panic_helper_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_helper_clear_description(void)
> +{
> +	struct drm_panic_line *desc_line = &panic_msg[panic_msg_lines - 1];
> +
> +	desc_line->len = 0;
> +	desc_line->txt = NULL;
> +}
> +
> +/**
> + * drm_plane_helper_display_panic_screen - Displays a panic screen according to the given settings
> + * @plane: the DRM plane to display to
> + * @description: error message to display
> + * @panic_type: type of panic screen
> + * @fg_color: text foreground color
> + * @bg_color: text background color
> + * @qr_version: version of the QR code, if any
> + *
> + * This helper display a panic screen on common primary planes. The panic
> + * screen can either display a kernel message, a user message or a QR code.
> + *
> + * The helper uses struct drm_plane_helper_funcs.get_scanout_buffer, where
> + * the plane can provide a scanout buffer that the panic handler can draw to.
> + * Currently only linear buffer and a few color formats are supported.
> + *
> + * Optionally the plane can also provide a &drm_plane_helper_funcs.panic_flush
> + * callback, which the DRM panic handler calls after drawing to send additional
> + * commands to the hardware to make the scanout buffer visible.
> + */
> +int drm_plane_helper_display_panic_screen(struct drm_plane *plane, const char *description,
> +					  enum drm_panic_type panic_type,
> +					  u32 fg_color, u32 bg_color, unsigned int qr_version)
> +{
> +	struct drm_scanout_buffer sb = { };
> +	int ret;
> +
> +	if (!plane->helper_private || !plane->helper_private->get_scanout_buffer)
> +		return -EINVAL;
> +
> +	ret = plane->helper_private->get_scanout_buffer(plane, &sb);
> +	if (ret)
> +		return ret;
> +
> +	if (!drm_panic_helper_format_is_supported(sb.format))
> +		return -EINVAL;
> +
> +	/* 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]))
> +		return -EINVAL;
> +
> +	drm_panic_helper_set_description(description);
> +
> +	ret = draw_panic_helper_dispatch(&sb, panic_type, fg_color, bg_color, qr_version);
> +	if (!ret) {
> +		/*
> +		 * Only flush if we have a panic screen to display. Otherwise
> +		 * it's probably better to leave the display output as-is.
> +		 */
> +		if (plane->helper_private->panic_flush)
> +			plane->helper_private->panic_flush(plane);
> +	}
> +
> +	drm_panic_helper_clear_description();
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_plane_helper_display_panic_screen);
> +
> +int __init drm_panic_helper_init(void)
> +{
> +	drm_panic_helper_setup_logo();
> +	drm_panic_helper_qr_init();
> +
> +	return 0;
> +}
> +
> +void __exit drm_panic_helper_exit(void)
> +{
> +	drm_panic_helper_qr_exit();
> +}
> +
> +#ifdef CONFIG_DRM_KUNIT_TEST
> +#include "tests/drm_panic_helper_test.c"
> +#endif
> diff --git a/drivers/gpu/drm/drm_panic_qr.rs b/drivers/gpu/drm/drm_panic_helper_qr.rs
> similarity index 99%
> rename from drivers/gpu/drm/drm_panic_qr.rs
> rename to drivers/gpu/drm/drm_panic_helper_qr.rs
> index ac27e86c601c..22966956331e 100644
> --- a/drivers/gpu/drm/drm_panic_qr.rs
> +++ b/drivers/gpu/drm/drm_panic_helper_qr.rs
> @@ -938,7 +938,7 @@ fn draw_all(&mut self, data: impl Iterator<Item = u8>) {
>   ///
>   /// They must remain valid for the duration of the function call.
>   #[export]
> -pub unsafe extern "C" fn drm_panic_qr_generate(
> +pub unsafe extern "C" fn drm_panic_helper_qr_generate(
>       url: *const kernel::ffi::c_char,
>       data: *mut u8,
>       data_len: usize,
> @@ -994,7 +994,7 @@ fn draw_all(&mut self, data: impl Iterator<Item = u8>) {
>   /// Always safe to call.
>   // Required to be unsafe due to the `#[export]` annotation.
>   #[export]
> -pub unsafe extern "C" fn drm_panic_qr_max_data_size(version: u8, url_len: usize) -> usize {
> +pub unsafe extern "C" fn drm_panic_helper_qr_max_data_size(version: u8, url_len: usize) -> usize {
>       #[expect(clippy::manual_range_contains)]
>       if version < 1 || version > 40 {
>           return 0;
> diff --git a/drivers/gpu/drm/drm_panic_internal.h b/drivers/gpu/drm/drm_panic_internal.h
> index c68d64c56e15..fe6d514a0833 100644
> --- a/drivers/gpu/drm/drm_panic_internal.h
> +++ b/drivers/gpu/drm/drm_panic_internal.h
> @@ -52,4 +52,18 @@ static inline void drm_panic_lock(struct drm_device *dev, unsigned long flags) {
>   static inline void drm_panic_unlock(struct drm_device *dev, unsigned long flags) {}
>   #endif
>   
> +#if IS_ENABLED(CONFIG_DRM_PANIC_HELPER)
> +/* drm_panic_helper.c */
> +int __init drm_panic_helper_init(void);
> +void __exit drm_panic_helper_exit(void);
> +#else
> +static inline int __init drm_panic_helper_init(void)
> +{
> +	return 0;
> +}
> +
> +static inline void __exit drm_panic_helper_exit(void)
> +{ }
> +#endif
> +
>   #endif /* __DRM_PANIC_INTERNAL_H__ */
> diff --git a/drivers/gpu/drm/tests/drm_panic_test.c b/drivers/gpu/drm/tests/drm_panic_helper_test.c
> similarity index 88%
> rename from drivers/gpu/drm/tests/drm_panic_test.c
> rename to drivers/gpu/drm/tests/drm_panic_helper_test.c
> index 55d77bc203df..e6befe0f1c83 100644
> --- a/drivers/gpu/drm/tests/drm_panic_test.c
> +++ b/drivers/gpu/drm/tests/drm_panic_helper_test.c
> @@ -3,7 +3,7 @@
>    * Copyright (c) 2025 Red Hat.
>    * Author: Jocelyn Falempe <jfalempe@redhat.com>
>    *
> - * KUNIT tests for drm panic
> + * KUNIT tests for DRM panic helpers
>    */
>   
>   #include <drm/drm_fourcc.h>
> @@ -41,24 +41,24 @@ struct drm_test_mode {
>   	.width = w, \
>   	.height = h, \
>   	.format = f, \
> -	.draw_screen = draw_panic_screen_ ## name ## _default, \
> +	.draw_screen = drm_panic_helper_draw_screen_ ## name ## _default, \
>   	.fname = #name, \
>   	}, \
>   
> -static int draw_panic_screen_user_default(struct drm_scanout_buffer *sb)
> +static int drm_panic_helper_draw_screen_user_default(struct drm_scanout_buffer *sb)
>   {
> -	return draw_panic_screen_user(sb, 0x00ffffff, 0x00000000);
> +	return drm_panic_helper_draw_screen_user(sb, 0x00ffffff, 0x00000000);
>   }
>   
> -static int draw_panic_screen_kmsg_default(struct drm_scanout_buffer *sb)
> +static int drm_panic_helper_draw_screen_kmsg_default(struct drm_scanout_buffer *sb)
>   {
> -	return draw_panic_screen_kmsg(sb, 0x00ffffff, 0x00000000);
> +	return drm_panic_helper_draw_screen_kmsg(sb, 0x00ffffff, 0x00000000);
>   }
>   
>   #if IS_ENABLED(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> -static int draw_panic_screen_qr_code_default(struct drm_scanout_buffer *sb)
> +static int drm_panic_helper_draw_screen_qr_code_default(struct drm_scanout_buffer *sb)
>   {
> -	return draw_panic_screen_qr_code(sb, 0x00ffffff, 0x00000000, 40);
> +	return drm_panic_helper_draw_screen_qr_code(sb, 0x00ffffff, 0x00000000, 40);
>   }
>   #endif
>   
> @@ -81,7 +81,7 @@ static int drm_test_panic_init(struct kunit *test)
>   
>   	test->priv = priv;
>   
> -	drm_panic_set_description("Kunit testing");
> +	drm_panic_helper_set_description("Kunit testing");
>   
>   	return 0;
>   }
> @@ -226,10 +226,10 @@ static struct kunit_case drm_panic_screen_user_test[] = {
>   	{ }
>   };
>   
> -static struct kunit_suite drm_panic_suite = {
> -	.name = "drm_panic",
> +static struct kunit_suite drm_panic_helper_suite = {
> +	.name = "drm_panic_helper",
>   	.init = drm_test_panic_init,
>   	.test_cases = drm_panic_screen_user_test,
>   };
>   
> -kunit_test_suite(drm_panic_suite);
> +kunit_test_suite(drm_panic_helper_suite);
> diff --git a/include/drm/drm_panic.h b/include/drm/drm_panic.h
> index 99572b7eeab9..3e628cbaffca 100644
> --- a/include/drm/drm_panic.h
> +++ b/include/drm/drm_panic.h
> @@ -85,11 +85,4 @@ struct drm_scanout_buffer {
>   	void *private;
>   };
>   
> -#if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> -size_t drm_panic_qr_max_data_size(u8 version, size_t url_len);
> -
> -u8 drm_panic_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size,
> -			 u8 *tmp, size_t tmp_size);
> -#endif
> -
>   #endif /* __DRM_PANIC_H__ */
> diff --git a/include/drm/drm_panic_helper.h b/include/drm/drm_panic_helper.h
> index 0b6ad8f61821..6cc9a0eba077 100644
> --- a/include/drm/drm_panic_helper.h
> +++ b/include/drm/drm_panic_helper.h
> @@ -16,6 +16,11 @@ int drm_plane_helper_display_panic_screen(struct drm_plane *plane,
>   					  u32 fg_color, u32 bg_color,
>   					  unsigned int qr_version);
>   
> +/* drm_panic_helper_qr.rs */
> +size_t drm_panic_helper_qr_max_data_size(u8 version, size_t url_len);
> +u8 drm_panic_helper_qr_generate(const char *url, u8 *data, size_t data_len, size_t data_size,
> +				u8 *tmp, size_t tmp_size);
> +
>   #if IS_ENABLED(CONFIG_DRM_PANIC)
>   #define DRM_PANIC_PLANE_FUNCS \
>   	.display_panic_screen = drm_plane_helper_display_panic_screen
> diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h
> index 4b31aa7f432f..d14d076ac883 100644
> --- a/rust/bindings/bindings_helper.h
> +++ b/rust/bindings/bindings_helper.h
> @@ -106,8 +106,8 @@
>   #include <../../drivers/base/base.h>
>   
>   #if defined(CONFIG_DRM_PANIC_SCREEN_QR_CODE)
> -// Used by `#[export]` in `drivers/gpu/drm/drm_panic_qr.rs`.
> -#include <drm/drm_panic.h>
> +// Used by `#[export]` in `drivers/gpu/drm/drm_panic_helper_qr.rs`.
> +#include <drm/drm_panic_helper.h>
>   #endif
>   
>   /* `bindgen` gets confused at certain things. */