[PATCH v2 00/13] vc,fbcon,fonts: Proper handling of font data

[PATCH v2 00/13] vc,fbcon,fonts: Proper handling of font data

[Thomas Zimmermann]

Provide helpers for handling console font data. Update consoles and VT.

VT's vc_state stores font data as a plain byte array of glphys. Fbcon,
newport_con and the kernel's internal fonts store the glyph data as an
array of plain bytes plus a hidden header for reference counting, check
sums and buffer sizes. The reference counting only works for user-space
fonts but not for internal fonts. Font-data handling is duplicated in
several places. Most of the font handling is open-coded and mixed up with
VT's plain glyph arrays.

To address these issues, add proper handling of font data to all involved
components: struct vc_font for font state in VC; a font data type for the
consoles. Then implement interfaces for handling font data one by one.

Patch 1 prepares the fbdev interface.

Patches 2 to 4 prepare VT's font handling.

Patches 5 to 13 refactor fbcon and newport_con to use clean interfaces for
their fonts.

Fbcon has long been a source of problems and bug reports. [1] With its
confusing implementation, it is hard to find the cause of these bugs.
Cleaning up the fbcon code will hopefully help with resolving bug reports
in the future.

The series has been tested with fbcon under DRM's bochs driver by changing
fonts at runtime using the setfont utility. [2] The changes to newport_con
have only been tested to compile.

v2:
- keep declaring the internal fonts in the public header file (Helge)
- rebase and clean up

[1] https://lore.kernel.org/all/6992c84c.a70a0220.2c38d7.00e8.GAE@google.com/
[2] https://www.man7.org/linux/man-pages/man8/setfont.8.html

Thomas Zimmermann (13):
  fbdev: Declare src parameter of fb_pad_ helpers as constant
  vt: Remove trailing whitespaces
  vt: Store font in struct vc_font
  vt: Calculate font-buffer size with vc_font_size()
  lib/fonts: Remove trailing whitespaces
  lib/fonts: Remove FNTCHARCNT()
  lib/fonts: Store font data as font_data_t; update consoles
  lib/fonts: Read font size with font_data_size()
  lib/fonts: Compare font data for equality with font_data_is_equal()
  lib/fonts: Manage font-data lifetime with font_data_get/_put()
  lib/fonts: Create font_data_t from struct console_font with
    font_data_import()
  lib/fonts: Store font data for user space with font_data_export()
  lib/fonts: Remove internal symbols and macros from public header file

 drivers/video/console/newport_con.c |  61 +++----
 drivers/video/fbdev/core/bitblit.c  |  11 +-
 drivers/video/fbdev/core/fbcon.c    | 194 +++++++----------------
 drivers/video/fbdev/core/fbcon.h    |   8 +-
 drivers/video/fbdev/core/fbmem.c    |   6 +-
 include/linux/console_struct.h      |  59 ++++++-
 include/linux/fb.h                  |  10 +-
 include/linux/font.h                | 115 +++++++++-----
 lib/fonts/font.h                    |  38 +++++
 lib/fonts/font_10x18.c              |   2 +-
 lib/fonts/font_6x10.c               |   3 +-
 lib/fonts/font_6x11.c               |   2 +-
 lib/fonts/font_6x8.c                |   3 +-
 lib/fonts/font_7x14.c               |   2 +-
 lib/fonts/font_8x16.c               |   3 +-
 lib/fonts/font_8x8.c                |   2 +-
 lib/fonts/font_acorn_8x8.c          |   4 +-
 lib/fonts/font_mini_4x6.c           |  10 +-
 lib/fonts/font_pearl_8x8.c          |   2 +-
 lib/fonts/font_sun12x22.c           |   3 +-
 lib/fonts/font_sun8x16.c            |   3 +-
 lib/fonts/font_ter10x18.c           |   4 +-
 lib/fonts/font_ter16x32.c           |   4 +-
 lib/fonts/fonts.c                   | 236 +++++++++++++++++++++++++++-
 24 files changed, 518 insertions(+), 267 deletions(-)
 create mode 100644 lib/fonts/font.h


base-commit: e57ac53f3ef90826a0b5b7cdf7f1e742a2aa1e9b
-- 
2.53.0

[PATCH v2 01/13] fbdev: Declare src parameter of fb_pad_ helpers as constant

[Thomas Zimmermann]

Fbdev's padding helpers do not modify the source buffer. Declare the
parameter as 'const'.

Fbcon's font-rendering code calls these helpers with the font data.
Declaring src as const will allow for making the font data constant
as well.

While at it, also remove the extern qualifier from the function
declarations in the header file.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/core/fbmem.c |  6 +++---
 include/linux/fb.h               | 10 +++++-----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index cf199038f069..30f2b59c47bf 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -91,14 +91,14 @@ EXPORT_SYMBOL(fb_get_color_depth);
 /*
  * Data padding functions.
  */
-void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u32 height)
+void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, const u8 *src, u32 s_pitch, u32 height)
 {
 	__fb_pad_aligned_buffer(dst, d_pitch, src, s_pitch, height);
 }
 EXPORT_SYMBOL(fb_pad_aligned_buffer);
 
-void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 idx, u32 height,
-				u32 shift_high, u32 shift_low, u32 mod)
+void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, const u8 *src, u32 idx, u32 height,
+			     u32 shift_high, u32 shift_low, u32 mod)
 {
 	u8 mask = (u8) (0xff << shift_high), tmp;
 	int i, j;
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 6d4a58084fd5..324b0fd5f617 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -605,9 +605,9 @@ extern int register_framebuffer(struct fb_info *fb_info);
 extern void unregister_framebuffer(struct fb_info *fb_info);
 extern int devm_register_framebuffer(struct device *dev, struct fb_info *fb_info);
 extern char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size);
-extern void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 idx,
-				u32 height, u32 shift_high, u32 shift_low, u32 mod);
-extern void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 s_pitch, u32 height);
+void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, const u8 *src, u32 idx, u32 height,
+			     u32 shift_high, u32 shift_low, u32 mod);
+void fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, const u8 *src, u32 s_pitch, u32 height);
 extern void fb_set_suspend(struct fb_info *info, int state);
 extern int fb_get_color_depth(struct fb_var_screeninfo *var,
 			      struct fb_fix_screeninfo *fix);
@@ -633,8 +633,8 @@ static inline struct device *dev_of_fbinfo(const struct fb_info *info)
 #endif
 }
 
-static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch,
-					   u8 *src, u32 s_pitch, u32 height)
+static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, const u8 *src, u32 s_pitch,
+					   u32 height)
 {
 	u32 i, j;
 
-- 
2.53.0

[PATCH v2 02/13] vt: Remove trailing whitespaces

[Thomas Zimmermann]

Fix coding style. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 include/linux/console_struct.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index 13b35637bd5a..ebdb9750d348 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -120,7 +120,7 @@ struct vc_data {
 	unsigned short	vc_complement_mask;	/* [#] Xor mask for mouse pointer */
 	unsigned short	vc_s_complement_mask;	/* Saved mouse pointer mask */
 	unsigned long	vc_pos;			/* Cursor address */
-	/* fonts */	
+	/* fonts */
 	unsigned short	vc_hi_font_mask;	/* [#] Attribute set for upper 256 chars of font or 0 if not supported */
 	struct console_font vc_font;		/* Current VC font set */
 	unsigned short	vc_video_erase_char;	/* Background erase character */
-- 
2.53.0

[PATCH v2 03/13] vt: Store font in struct vc_font

[Thomas Zimmermann]

Replace struct console_font with struct vc_font for the type of the
vc_font field of struct vc_data. Struct console_font is UAPI, which
prevents further changes. Hence a new data type is required.

Struct console_font has a documented vertical pitch of 32 bytes. This
is not the case after the font data has been loaded into the kernel.
Changing the type of vc_font addresses this inconsistency.

The font data is now declared as constant, as it might come from the
kernel's read-only section. There's some fallout throughout the console
code where non-const variables refer to it. Fix them. A later update
will declare the font data to a dedicated data type.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/core/bitblit.c | 11 +++++------
 drivers/video/fbdev/core/fbcon.c   |  4 ++--
 drivers/video/fbdev/core/fbcon.h   |  4 ++--
 include/linux/console_struct.h     | 29 +++++++++++++++++++++++++++--
 4 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/drivers/video/fbdev/core/bitblit.c b/drivers/video/fbdev/core/bitblit.c
index 085ffb44c51a..7478accea8ec 100644
--- a/drivers/video/fbdev/core/bitblit.c
+++ b/drivers/video/fbdev/core/bitblit.c
@@ -22,8 +22,7 @@
 /*
  * Accelerated handlers.
  */
-static void update_attr(u8 *dst, u8 *src, int attribute,
-			       struct vc_data *vc)
+static void update_attr(u8 *dst, const u8 *src, int attribute, struct vc_data *vc)
 {
 	int i, offset = (vc->vc_font.height < 10) ? 1 : 2;
 	int width = DIV_ROUND_UP(vc->vc_font.width, 8);
@@ -81,7 +80,7 @@ static inline void bit_putcs_aligned(struct vc_data *vc, struct fb_info *info,
 	u16 charmask = vc->vc_hi_font_mask ? 0x1ff : 0xff;
 	unsigned int charcnt = vc->vc_font.charcount;
 	u32 idx = vc->vc_font.width >> 3;
-	u8 *src;
+	const u8 *src;
 
 	while (cnt--) {
 		u16 ch = scr_readw(s++) & charmask;
@@ -120,7 +119,7 @@ static inline void bit_putcs_unaligned(struct vc_data *vc,
 	u32 shift_low = 0, mod = vc->vc_font.width % 8;
 	u32 shift_high = 8;
 	u32 idx = vc->vc_font.width >> 3;
-	u8 *src;
+	const u8 *src;
 
 	while (cnt--) {
 		u16 ch = scr_readw(s++) & charmask;
@@ -267,7 +266,7 @@ static void bit_cursor(struct vc_data *vc, struct fb_info *info, bool enable,
 	int y = real_y(par->p, vc->state.y);
 	int attribute, use_sw = vc->vc_cursor_type & CUR_SW;
 	int err = 1;
-	char *src;
+	const u8 *src;
 
 	cursor.set = 0;
 
@@ -278,7 +277,7 @@ static void bit_cursor(struct vc_data *vc, struct fb_info *info, bool enable,
 	attribute = get_attribute(info, c);
 	src = vc->vc_font.data + ((c & charmask) * (w * vc->vc_font.height));
 
-	if (par->cursor_state.image.data != src ||
+	if (par->cursor_state.image.data != (const char *)src ||
 	    par->cursor_reset) {
 		par->cursor_state.image.data = src;
 		cursor.set |= FB_CUR_SETIMAGE;
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 666261ae59d8..247bb90c08d3 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -2286,7 +2286,7 @@ static bool fbcon_blank(struct vc_data *vc, enum vesa_blank_mode blank,
 
 static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigned int vpitch)
 {
-	u8 *fontdata = vc->vc_font.data;
+	const u8 *fontdata = vc->vc_font.data;
 	u8 *data = font->data;
 	int i, j;
 
@@ -2417,7 +2417,7 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
 	struct fbcon_par *par = info->fbcon_par;
 	struct fbcon_display *p = &fb_display[vc->vc_num];
 	int resize, ret, old_userfont, old_width, old_height, old_charcount;
-	u8 *old_data = vc->vc_font.data;
+	const u8 *old_data = vc->vc_font.data;
 
 	resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
 	vc->vc_font.data = (void *)(p->fontdata = data);
diff --git a/drivers/video/fbdev/core/fbcon.h b/drivers/video/fbdev/core/fbcon.h
index fca14e9b729b..3f4386a40237 100644
--- a/drivers/video/fbdev/core/fbcon.h
+++ b/drivers/video/fbdev/core/fbcon.h
@@ -82,8 +82,8 @@ struct fbcon_par {
 	int    rotate;
 	int    cur_rotate;
 	char  *cursor_data;
-	u8    *fontbuffer;
-	u8    *fontdata;
+	u8          *fontbuffer;
+	const u8    *fontdata;
 	u8    *cursor_src;
 	u32    cursor_size;
 	u32    fd_size;
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index ebdb9750d348..7fdcae6ed49c 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -13,8 +13,9 @@
 #ifndef _LINUX_CONSOLE_STRUCT_H
 #define _LINUX_CONSOLE_STRUCT_H
 
-#include <linux/wait.h>
+#include <linux/math.h>
 #include <linux/vt.h>
+#include <linux/wait.h>
 #include <linux/workqueue.h>
 
 struct uni_pagedict;
@@ -58,6 +59,30 @@ struct vc_state {
 	bool		reverse;
 };
 
+/**
+ * struct vc_font - Describes a font
+ * @width: The width of a single glyph in bits
+ * @height: The height of a single glyph in scanlines
+ * @charcount: The number of glyphs in the font
+ * @data: The raw font data
+ *
+ * Font data is organized as an array of glyphs. Each glyph is a bitmap with
+ * set bits indicating the foreground color. Unset bits indicate background
+ * color. The fields @width and @height store a single glyph's number of
+ * horizontal bits and vertical scanlines. If width is not a multiple of 8,
+ * there are trailing bits to fill up the byte. These bits should not be drawn.
+ *
+ * The field @data points to the first glphy's first byte. The value @charcount
+ * gives the number of glyphs in the font. There are no empty scanlines between
+ * two adjacent glyphs.
+ */
+struct vc_font {
+	unsigned int width;
+	unsigned int height;
+	unsigned int charcount;
+	const unsigned char *data;
+};
+
 /*
  * Example: vc_data of a console that was scrolled 3 lines down.
  *
@@ -122,7 +147,7 @@ struct vc_data {
 	unsigned long	vc_pos;			/* Cursor address */
 	/* fonts */
 	unsigned short	vc_hi_font_mask;	/* [#] Attribute set for upper 256 chars of font or 0 if not supported */
-	struct console_font vc_font;		/* Current VC font set */
+	struct vc_font vc_font;			/* Current VC font set */
 	unsigned short	vc_video_erase_char;	/* Background erase character */
 	/* VT terminal data */
 	unsigned int	vc_state;		/* Escape sequence parser state */
-- 
2.53.0

Re: [PATCH v2 03/13] vt: Store font in struct vc_font

[Helge Deller]

On 3/2/26 15:08, Thomas Zimmermann wrote:
> Replace struct console_font with struct vc_font for the type of the
> vc_font field of struct vc_data. Struct console_font is UAPI, which
> prevents further changes. Hence a new data type is required.
> 
> Struct console_font has a documented vertical pitch of 32 bytes. This
> is not the case after the font data has been loaded into the kernel.
> Changing the type of vc_font addresses this inconsistency.
> 
> The font data is now declared as constant, as it might come from the
> kernel's read-only section. There's some fallout throughout the console
> code where non-const variables refer to it. Fix them. A later update
> will declare the font data to a dedicated data type.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>   drivers/video/fbdev/core/bitblit.c | 11 +++++------
>   drivers/video/fbdev/core/fbcon.c   |  4 ++--
>   drivers/video/fbdev/core/fbcon.h   |  4 ++--
>   include/linux/console_struct.h     | 29 +++++++++++++++++++++++++++--
>   4 files changed, 36 insertions(+), 12 deletions(-)
> 
....
> diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
> index ebdb9750d348..7fdcae6ed49c 100644
> --- a/include/linux/console_struct.h
> +++ b/include/linux/console_struct.h
> @@ -13,8 +13,9 @@
>   #ifndef _LINUX_CONSOLE_STRUCT_H
>   #define _LINUX_CONSOLE_STRUCT_H
>   
> -#include <linux/wait.h>
> +#include <linux/math.h>
>   #include <linux/vt.h>
> +#include <linux/wait.h>
>   #include <linux/workqueue.h>
>   
>   struct uni_pagedict;
> @@ -58,6 +59,30 @@ struct vc_state {
>   	bool		reverse;
>   };
>   
> +/**
> + * struct vc_font - Describes a font
> + * @width: The width of a single glyph in bits
> + * @height: The height of a single glyph in scanlines
> + * @charcount: The number of glyphs in the font
> + * @data: The raw font data
> + *
> + * Font data is organized as an array of glyphs. Each glyph is a bitmap with
> + * set bits indicating the foreground color. Unset bits indicate background
> + * color. The fields @width and @height store a single glyph's number of
> + * horizontal bits and vertical scanlines. If width is not a multiple of 8,
> + * there are trailing bits to fill up the byte. These bits should not be drawn.
> + *
> + * The field @data points to the first glphy's first byte. The value @charcount
> + * gives the number of glyphs in the font. There are no empty scanlines between
> + * two adjacent glyphs.
> + */
> +struct vc_font {
> +	unsigned int width;
> +	unsigned int height;
> +	unsigned int charcount;

I wonder if we shouldn't declare width and height as "u8" or "short int" type?
And charcount as u16 or "short int" ?
Makes later calculations shorter & easier.

Helge

Re: [PATCH v2 03/13] vt: Store font in struct vc_font

[Thomas Zimmermann]

Hi

Am 03.03.26 um 15:31 schrieb Helge Deller:
> On 3/2/26 15:08, Thomas Zimmermann wrote:
>> Replace struct console_font with struct vc_font for the type of the
>> vc_font field of struct vc_data. Struct console_font is UAPI, which
>> prevents further changes. Hence a new data type is required.
>>
>> Struct console_font has a documented vertical pitch of 32 bytes. This
>> is not the case after the font data has been loaded into the kernel.
>> Changing the type of vc_font addresses this inconsistency.
>>
>> The font data is now declared as constant, as it might come from the
>> kernel's read-only section. There's some fallout throughout the console
>> code where non-const variables refer to it. Fix them. A later update
>> will declare the font data to a dedicated data type.
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
>>   drivers/video/fbdev/core/bitblit.c | 11 +++++------
>>   drivers/video/fbdev/core/fbcon.c   |  4 ++--
>>   drivers/video/fbdev/core/fbcon.h   |  4 ++--
>>   include/linux/console_struct.h     | 29 +++++++++++++++++++++++++++--
>>   4 files changed, 36 insertions(+), 12 deletions(-)
>>
> ....
>> diff --git a/include/linux/console_struct.h 
>> b/include/linux/console_struct.h
>> index ebdb9750d348..7fdcae6ed49c 100644
>> --- a/include/linux/console_struct.h
>> +++ b/include/linux/console_struct.h
>> @@ -13,8 +13,9 @@
>>   #ifndef _LINUX_CONSOLE_STRUCT_H
>>   #define _LINUX_CONSOLE_STRUCT_H
>>   -#include <linux/wait.h>
>> +#include <linux/math.h>
>>   #include <linux/vt.h>
>> +#include <linux/wait.h>
>>   #include <linux/workqueue.h>
>>     struct uni_pagedict;
>> @@ -58,6 +59,30 @@ struct vc_state {
>>       bool        reverse;
>>   };
>>   +/**
>> + * struct vc_font - Describes a font
>> + * @width: The width of a single glyph in bits
>> + * @height: The height of a single glyph in scanlines
>> + * @charcount: The number of glyphs in the font
>> + * @data: The raw font data
>> + *
>> + * Font data is organized as an array of glyphs. Each glyph is a 
>> bitmap with
>> + * set bits indicating the foreground color. Unset bits indicate 
>> background
>> + * color. The fields @width and @height store a single glyph's 
>> number of
>> + * horizontal bits and vertical scanlines. If width is not a 
>> multiple of 8,
>> + * there are trailing bits to fill up the byte. These bits should 
>> not be drawn.
>> + *
>> + * The field @data points to the first glphy's first byte. The value 
>> @charcount
>> + * gives the number of glyphs in the font. There are no empty 
>> scanlines between
>> + * two adjacent glyphs.
>> + */
>> +struct vc_font {
>> +    unsigned int width;
>> +    unsigned int height;
>> +    unsigned int charcount;
>
> I wonder if we shouldn't declare width and height as "u8" or "short 
> int" type?
> And charcount as u16 or "short int" ?
> Makes later calculations shorter & easier.

That would be a change to vt and possibly affect a lot of consoles. In 
any case, I'd rather do this separately.

Best regards
Thomas

>
> Helge

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)

[PATCH v2 04/13] vt: Calculate font-buffer size with vc_font_size()

[Thomas Zimmermann]

In fbcon, fbcon_resize() computes the size of the font buffer from the
values stored in vc_font. Move these calculations to the dedicated helpers
vc_font_pitch() and vc_font_size().

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/fbdev/core/fbcon.c |  9 ++-------
 include/linux/console_struct.h   | 28 ++++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 247bb90c08d3..103e91c8d874 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -2037,7 +2037,6 @@ static void updatescrollmode(struct fbcon_display *p,
 }
 
 #define PITCH(w) (((w) + 7) >> 3)
-#define CALC_FONTSZ(h, p, c) ((h) * (p) * (c)) /* size = height * pitch * charcount */
 
 static int fbcon_resize(struct vc_data *vc, unsigned int width,
 			unsigned int height, bool from_user)
@@ -2049,8 +2048,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
 	int x_diff, y_diff, virt_w, virt_h, virt_fw, virt_fh;
 
 	if (p->userfont && FNTSIZE(vc->vc_font.data)) {
-		int size;
-		int pitch = PITCH(vc->vc_font.width);
+		unsigned int size = vc_font_size(&vc->vc_font);
 
 		/*
 		 * If user font, ensure that a possible change to user font
@@ -2059,10 +2057,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
 		 * charcount can change and cannot be used to determine the
 		 * font data allocated size.
 		 */
-		if (pitch <= 0)
-			return -EINVAL;
-		size = CALC_FONTSZ(vc->vc_font.height, pitch, vc->vc_font.charcount);
-		if (size > FNTSIZE(vc->vc_font.data))
+		if (!size || size > FNTSIZE(vc->vc_font.data))
 			return -EINVAL;
 	}
 
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index 7fdcae6ed49c..fbb5dd5f6761 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -83,6 +83,34 @@ struct vc_font {
 	const unsigned char *data;
 };
 
+/**
+ * vc_font_pitch - Calculates the number of bytes between two adjacent scanlines
+ * @font: The VC font
+ *
+ * Returns:
+ * The number of bytes between two adjacent scanlines in the font data
+ */
+static inline unsigned int vc_font_pitch(const struct vc_font *font)
+{
+	return DIV_ROUND_UP(font->width, 8);
+}
+
+/**
+ * vc_font_size - Calculates the size of the font data in bytes
+ * @font: The VC font
+ *
+ * vc_font_size() calculates the number of bytes of font data in the
+ * font specified by @font. The function calculates the size from the
+ * font parameters.
+ *
+ * Returns:
+ * The size of the font data in bytes.
+ */
+static inline unsigned int vc_font_size(const struct vc_font *font)
+{
+	return font->height * vc_font_pitch(font) * font->charcount;
+}
+
 /*
  * Example: vc_data of a console that was scrolled 3 lines down.
  *
-- 
2.53.0

[PATCH v2 05/13] lib/fonts: Remove trailing whitespaces

[Thomas Zimmermann]

Fix coding style. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 lib/fonts/font_acorn_8x8.c | 2 +-
 lib/fonts/font_mini_4x6.c  | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/lib/fonts/font_acorn_8x8.c b/lib/fonts/font_acorn_8x8.c
index 18755c33d249..af5fa72aa8b7 100644
--- a/lib/fonts/font_acorn_8x8.c
+++ b/lib/fonts/font_acorn_8x8.c
@@ -68,7 +68,7 @@ static const struct font_data acorndata_8x8 = {
 /* 3A */  0x00, 0x00, 0x18, 0x18, 0x00, 0x18, 0x18, 0x00, /* : */
 /* 3B */  0x00, 0x00, 0x18, 0x18, 0x00, 0x18, 0x18, 0x30, /* ; */
 /* 3C */  0x0C, 0x18, 0x30, 0x60, 0x30, 0x18, 0x0C, 0x00, /* < */
-/* 3D */  0x00, 0x00, 0x7E, 0x00, 0x7E, 0x00, 0x00, 0x00, /* = */ 
+/* 3D */  0x00, 0x00, 0x7E, 0x00, 0x7E, 0x00, 0x00, 0x00, /* = */
 /* 3E */  0x30, 0x18, 0x0C, 0x06, 0x0C, 0x18, 0x30, 0x00, /* > */
 /* 3F */  0x3C, 0x66, 0x0C, 0x18, 0x18, 0x00, 0x18, 0x00, /* ? */
 /* 40 */  0x3C, 0x66, 0x6E, 0x6A, 0x6E, 0x60, 0x3C, 0x00, /* @ */
diff --git a/lib/fonts/font_mini_4x6.c b/lib/fonts/font_mini_4x6.c
index 8d39fd447952..cc21dc70cfd1 100644
--- a/lib/fonts/font_mini_4x6.c
+++ b/lib/fonts/font_mini_4x6.c
@@ -18,15 +18,15 @@
 s{((0x)?[0-9a-fA-F]+)(.*\[([\*\ ]{4})\])}{
 
 	($num,$pat,$bits) = ($1,$3,$4);
-	
+
 	$bits =~ s/([^\s0])|(.)/ defined($1) + 0 /ge;
-	
+
 	$num = ord(pack("B8", $bits));
 	$num |= $num >> 4;
 	$num = sprintf("0x%.2x", $num);
-	
+
 	#print "$num,$pat,$bits\n";
-	
+
 	$num . $pat;
 }ge;
 
-- 
2.53.0

[PATCH v2 06/13] lib/fonts: Remove FNTCHARCNT()

[Thomas Zimmermann]

The character count in the font data is unused. The internal fonts also
do not set it. Remove FNTCHARCNT().

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/console/newport_con.c | 1 -
 include/linux/font.h                | 1 -
 2 files changed, 2 deletions(-)

diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index b178678566e7..e2922caa8685 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -516,7 +516,6 @@ static int newport_set_font(int unit, const struct console_font *op,
 
 	new_data += FONT_EXTRA_WORDS * sizeof(int);
 	FNTSIZE(new_data) = size;
-	FNTCHARCNT(new_data) = op->charcount;
 	REFCOUNT(new_data) = 0;	/* usage counter */
 	FNTSUM(new_data) = 0;
 
diff --git a/include/linux/font.h b/include/linux/font.h
index fd8625cd76b2..d929c5fa32ca 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -68,7 +68,6 @@ extern const struct font_desc *get_default_font(int xres, int yres,
 /* Extra word getters */
 #define REFCOUNT(fd)	(((int *)(fd))[-1])
 #define FNTSIZE(fd)	(((int *)(fd))[-2])
-#define FNTCHARCNT(fd)	(((int *)(fd))[-3])
 #define FNTSUM(fd)	(((int *)(fd))[-4])
 
 #define FONT_EXTRA_WORDS 4
-- 
2.53.0

[PATCH v2 07/13] lib/fonts: Store font data as font_data_t; update consoles

[Thomas Zimmermann]

Store font data as pointer to font_data_t instead of unsigned char.
Update consoles.

Pointers to font data refer to the raw data. There is a hidden header
before the data that contains additional state. Document the existing
layout and semantics of font_data_t.

The data field in struct vc_font can be used by any console. Therefore
it still points to plain data without the additional header. Fbcon sets
its value from struct fbcon_display.fontdata. Hence, update the size
test in fbcon_resize() to use struct fbcon_display.fontdata instead of
struct vc_font.data.

v2:
- 'Font lookup' -> 'Font description' in <linux/font.h>

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/console/newport_con.c | 17 ++++++-----
 drivers/video/fbdev/core/fbcon.c    | 44 ++++++++++++++++-----------
 drivers/video/fbdev/core/fbcon.h    |  3 +-
 include/linux/font.h                | 47 ++++++++++++++++++++++++++++-
 4 files changed, 84 insertions(+), 27 deletions(-)

diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index e2922caa8685..9b9ed1940404 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -33,9 +33,9 @@
 
 #define NEWPORT_LEN	0x10000
 
-#define FONT_DATA ((unsigned char *)font_vga_8x16.data)
+#define FONT_DATA font_vga_8x16.data
 
-static unsigned char *font_data[MAX_NR_CONSOLES];
+static font_data_t *font_data[MAX_NR_CONSOLES];
 
 static struct newport_regs *npregs;
 static unsigned long newport_addr;
@@ -370,9 +370,9 @@ static void newport_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
 static void newport_putc(struct vc_data *vc, u16 charattr, unsigned int ypos,
 			 unsigned int xpos)
 {
-	unsigned char *p;
+	const unsigned char *p;
 
-	p = &font_data[vc->vc_num][(charattr & 0xff) << 4];
+	p = &font_data_buf(font_data[vc->vc_num])[(charattr & 0xff) << 4];
 	charattr = (charattr >> 8) & 0xff;
 	xpos <<= 3;
 	ypos <<= 4;
@@ -400,7 +400,7 @@ static void newport_putcs(struct vc_data *vc, const u16 *s,
 			  unsigned int count, unsigned int ypos,
 			  unsigned int xpos)
 {
-	unsigned char *p;
+	const unsigned char *p;
 	unsigned int i;
 	u16 charattr;
 
@@ -424,7 +424,7 @@ static void newport_putcs(struct vc_data *vc, const u16 *s,
 				 NPORT_DMODE0_L32);
 
 	for (i = 0; i < count; i++, xpos += 8) {
-		p = &font_data[vc->vc_num][(scr_readw(s++) & 0xff) << 4];
+		p = &font_data_buf(font_data[vc->vc_num])[(scr_readw(s++) & 0xff) << 4];
 
 		newport_wait(npregs);
 
@@ -503,7 +503,8 @@ static int newport_set_font(int unit, const struct console_font *op,
 	int h = op->height;
 	int size = h * op->charcount;
 	int i;
-	unsigned char *new_data, *data = op->data, *p;
+	font_data_t *new_data;
+	unsigned char *data = op->data, *p;
 
 	/* ladis: when I grow up, there will be a day... and more sizes will
 	 * be supported ;-) */
@@ -519,7 +520,7 @@ static int newport_set_font(int unit, const struct console_font *op,
 	REFCOUNT(new_data) = 0;	/* usage counter */
 	FNTSUM(new_data) = 0;
 
-	p = new_data;
+	p = (unsigned char *)font_data_buf(new_data);
 	for (i = 0; i < op->charcount; i++) {
 		memcpy(p, data, h);
 		data += 32;
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 103e91c8d874..8d7840b9ebad 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -1019,8 +1019,10 @@ static const char *fbcon_startup(void)
 						info->pixmap.blit_y);
 		vc->vc_font.width = font->width;
 		vc->vc_font.height = font->height;
-		vc->vc_font.data = (void *)(p->fontdata = font->data);
+		vc->vc_font.data = font_data_buf(font->data);
 		vc->vc_font.charcount = font->charcount;
+
+		p->fontdata = font->data;
 	}
 
 	cols = FBCON_SWAP(par->rotate, info->var.xres, info->var.yres);
@@ -1078,11 +1080,12 @@ static void fbcon_init(struct vc_data *vc, bool init)
 		if (t->fontdata) {
 			struct vc_data *fvc = vc_cons[fg_console].d;
 
-			vc->vc_font.data = (void *)(p->fontdata =
-						    fvc->vc_font.data);
+			vc->vc_font.data = fvc->vc_font.data;
 			vc->vc_font.width = fvc->vc_font.width;
 			vc->vc_font.height = fvc->vc_font.height;
 			vc->vc_font.charcount = fvc->vc_font.charcount;
+
+			p->fontdata = t->fontdata;
 			p->userfont = t->userfont;
 
 			if (p->userfont)
@@ -1097,8 +1100,10 @@ static void fbcon_init(struct vc_data *vc, bool init)
 							info->pixmap.blit_y);
 			vc->vc_font.width = font->width;
 			vc->vc_font.height = font->height;
-			vc->vc_font.data = (void *)(p->fontdata = font->data);
+			vc->vc_font.data = font_data_buf(font->data);
 			vc->vc_font.charcount = font->charcount;
+
+			p->fontdata = font->data;
 		}
 	}
 
@@ -1409,11 +1414,12 @@ static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
 	svc = *default_mode;
 	t = &fb_display[svc->vc_num];
 
-	if (!vc->vc_font.data) {
-		vc->vc_font.data = (void *)(p->fontdata = t->fontdata);
+	if (!p->fontdata) {
+		vc->vc_font.data = font_data_buf(t->fontdata);
 		vc->vc_font.width = (*default_mode)->vc_font.width;
 		vc->vc_font.height = (*default_mode)->vc_font.height;
 		vc->vc_font.charcount = (*default_mode)->vc_font.charcount;
+		p->fontdata = t->fontdata;
 		p->userfont = t->userfont;
 		if (p->userfont)
 			REFCOUNT(p->fontdata)++;
@@ -2047,7 +2053,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
 	struct fb_var_screeninfo var = info->var;
 	int x_diff, y_diff, virt_w, virt_h, virt_fw, virt_fh;
 
-	if (p->userfont && FNTSIZE(vc->vc_font.data)) {
+	if (p->userfont && FNTSIZE(p->fontdata)) {
 		unsigned int size = vc_font_size(&vc->vc_font);
 
 		/*
@@ -2057,7 +2063,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
 		 * charcount can change and cannot be used to determine the
 		 * font data allocated size.
 		 */
-		if (!size || size > FNTSIZE(vc->vc_font.data))
+		if (!size || size > FNTSIZE(p->fontdata))
 			return -EINVAL;
 	}
 
@@ -2281,7 +2287,8 @@ static bool fbcon_blank(struct vc_data *vc, enum vesa_blank_mode blank,
 
 static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigned int vpitch)
 {
-	const u8 *fontdata = vc->vc_font.data;
+	struct fbcon_display *p = &fb_display[vc->vc_num];
+	font_data_t *fontdata = p->fontdata;
 	u8 *data = font->data;
 	int i, j;
 
@@ -2406,16 +2413,18 @@ static void set_vc_hi_font(struct vc_data *vc, bool set)
 }
 
 static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
-			     const u8 * data, int userfont)
+			     font_data_t *data, int userfont)
 {
 	struct fb_info *info = fbcon_info_from_console(vc->vc_num);
 	struct fbcon_par *par = info->fbcon_par;
 	struct fbcon_display *p = &fb_display[vc->vc_num];
 	int resize, ret, old_userfont, old_width, old_height, old_charcount;
+	font_data_t *old_fontdata = p->fontdata;
 	const u8 *old_data = vc->vc_font.data;
 
 	resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
-	vc->vc_font.data = (void *)(p->fontdata = data);
+	p->fontdata = data;
+	vc->vc_font.data = font_data_buf(p->fontdata);
 	old_userfont = p->userfont;
 	if ((p->userfont = userfont))
 		REFCOUNT(data)++;
@@ -2448,12 +2457,12 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
 		update_screen(vc);
 	}
 
-	if (old_userfont && (--REFCOUNT(old_data) == 0))
-		kfree(old_data - FONT_EXTRA_WORDS * sizeof(int));
+	if (old_userfont && (--REFCOUNT(old_fontdata) == 0))
+		kfree(old_fontdata - FONT_EXTRA_WORDS * sizeof(int));
 	return 0;
 
 err_out:
-	p->fontdata = old_data;
+	p->fontdata = old_fontdata;
 	vc->vc_font.data = old_data;
 
 	if (userfont) {
@@ -2483,7 +2492,8 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 	int h = font->height;
 	int size, alloc_size;
 	int i, csum;
-	u8 *new_data, *data = font->data;
+	font_data_t *new_data;
+	u8 *data = font->data;
 	int pitch = PITCH(font->width);
 
 	/* Is there a reason why fbconsole couldn't handle any charcount >256?
@@ -2522,13 +2532,13 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 	if (!new_data)
 		return -ENOMEM;
 
-	memset(new_data, 0, FONT_EXTRA_WORDS * sizeof(int));
+	memset((u8 *)new_data, 0, FONT_EXTRA_WORDS * sizeof(int));
 
 	new_data += FONT_EXTRA_WORDS * sizeof(int);
 	FNTSIZE(new_data) = size;
 	REFCOUNT(new_data) = 0;	/* usage counter */
 	for (i=0; i< charcount; i++) {
-		memcpy(new_data + i*h*pitch, data +  i*vpitch*pitch, h*pitch);
+		memcpy((u8 *)new_data + i * h * pitch, data + i * vpitch * pitch, h * pitch);
 	}
 
 	/* Since linux has a nice crc32 function use it for counting font
diff --git a/drivers/video/fbdev/core/fbcon.h b/drivers/video/fbdev/core/fbcon.h
index 3f4386a40237..d26ee7860cf5 100644
--- a/drivers/video/fbdev/core/fbcon.h
+++ b/drivers/video/fbdev/core/fbcon.h
@@ -11,6 +11,7 @@
 #ifndef _VIDEO_FBCON_H
 #define _VIDEO_FBCON_H
 
+#include <linux/font.h>
 #include <linux/types.h>
 #include <linux/vt_buffer.h>
 #include <linux/vt_kern.h>
@@ -25,7 +26,7 @@
 
 struct fbcon_display {
     /* Filled in by the low-level console driver */
-    const u_char *fontdata;
+    font_data_t *fontdata;
     int userfont;                   /* != 0 if fontdata kmalloc()ed */
 #ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
     u_short scrollmode;             /* Scroll Method, use fb_scrollmode() */
diff --git a/include/linux/font.h b/include/linux/font.h
index d929c5fa32ca..f19abd112c18 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -13,12 +13,57 @@
 
 #include <linux/types.h>
 
+/*
+ * font_data_t and helpers
+ */
+
+/**
+ * font_data_t - Raw font data
+ *
+ * Values of type font_data_t store a pointer to raw font data. The format
+ * is monochrome. Each bit sets a pixel of a stored glyph. Font data does
+ * not store geometry information for the individual glyphs. Users of the
+ * font have to store glyph size, pitch and characer count separately.
+ *
+ * Font data in font_data_t is not equivalent to raw u8. Each pointer stores
+ * an additional hidden header before the fotn data. The layout is
+ *
+ * +------+-----------------------------+
+ * | -16  |  CRC32 Checksum (optional)  |
+ * | -12  |  <Unused>                   |
+ * |  -8  |  Number of data bytes       |
+ * |  -4  |  Reference count            |
+ * +------+-----------------------------+
+ * |   0  |  Data buffer                |
+ * |  ... |                             |
+ * +------+-----------------------------+
+ *
+ * Use helpers to access font_data_t. Use font_data_buf() to get the stored data.
+ */
+typedef const unsigned char font_data_t;
+
+/**
+ * font_data_buf() - Returns the font data as raw bytes
+ * @fd: The font data
+ *
+ * Returns:
+ * The raw font data. The provided buffer is read-only.
+ */
+static inline const unsigned char *font_data_buf(font_data_t *fd)
+{
+	return (const unsigned char *)fd;
+}
+
+/*
+ * Font description
+ */
+
 struct font_desc {
     int idx;
     const char *name;
     unsigned int width, height;
     unsigned int charcount;
-    const void *data;
+    font_data_t *data;
     int pref;
 };
 
-- 
2.53.0

Re: [PATCH v2 07/13] lib/fonts: Store font data as font_data_t; update consoles

[Helge Deller]

On 3/2/26 15:08, Thomas Zimmermann wrote:
> Store font data as pointer to font_data_t instead of unsigned char.
> Update consoles.
> 
> Pointers to font data refer to the raw data. There is a hidden header
> before the data that contains additional state. Document the existing
> layout and semantics of font_data_t.
> 
> The data field in struct vc_font can be used by any console. Therefore
> it still points to plain data without the additional header. Fbcon sets
> its value from struct fbcon_display.fontdata. Hence, update the size
> test in fbcon_resize() to use struct fbcon_display.fontdata instead of
> struct vc_font.data.
> 
> v2:
> - 'Font lookup' -> 'Font description' in <linux/font.h>
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>   drivers/video/console/newport_con.c | 17 ++++++-----
>   drivers/video/fbdev/core/fbcon.c    | 44 ++++++++++++++++-----------
>   drivers/video/fbdev/core/fbcon.h    |  3 +-
>   include/linux/font.h                | 47 ++++++++++++++++++++++++++++-
>   4 files changed, 84 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
> index e2922caa8685..9b9ed1940404 100644
> --- a/drivers/video/console/newport_con.c
> +++ b/drivers/video/console/newport_con.c
> @@ -33,9 +33,9 @@
>   
>   #define NEWPORT_LEN	0x10000
>   
> -#define FONT_DATA ((unsigned char *)font_vga_8x16.data)
> +#define FONT_DATA font_vga_8x16.data
>   
> -static unsigned char *font_data[MAX_NR_CONSOLES];
> +static font_data_t *font_data[MAX_NR_CONSOLES];
>   
>   static struct newport_regs *npregs;
>   static unsigned long newport_addr;
> @@ -370,9 +370,9 @@ static void newport_clear(struct vc_data *vc, unsigned int sy, unsigned int sx,
>   static void newport_putc(struct vc_data *vc, u16 charattr, unsigned int ypos,
>   			 unsigned int xpos)
>   {
> -	unsigned char *p;
> +	const unsigned char *p;
>   
> -	p = &font_data[vc->vc_num][(charattr & 0xff) << 4];
> +	p = &font_data_buf(font_data[vc->vc_num])[(charattr & 0xff) << 4];
>   	charattr = (charattr >> 8) & 0xff;
>   	xpos <<= 3;
>   	ypos <<= 4;
> @@ -400,7 +400,7 @@ static void newport_putcs(struct vc_data *vc, const u16 *s,
>   			  unsigned int count, unsigned int ypos,
>   			  unsigned int xpos)
>   {
> -	unsigned char *p;
> +	const unsigned char *p;
>   	unsigned int i;
>   	u16 charattr;
>   
> @@ -424,7 +424,7 @@ static void newport_putcs(struct vc_data *vc, const u16 *s,
>   				 NPORT_DMODE0_L32);
>   
>   	for (i = 0; i < count; i++, xpos += 8) {
> -		p = &font_data[vc->vc_num][(scr_readw(s++) & 0xff) << 4];
> +		p = &font_data_buf(font_data[vc->vc_num])[(scr_readw(s++) & 0xff) << 4];
>   
>   		newport_wait(npregs);
>   
> @@ -503,7 +503,8 @@ static int newport_set_font(int unit, const struct console_font *op,
>   	int h = op->height;
>   	int size = h * op->charcount;
>   	int i;
> -	unsigned char *new_data, *data = op->data, *p;
> +	font_data_t *new_data;
> +	unsigned char *data = op->data, *p;
>   
>   	/* ladis: when I grow up, there will be a day... and more sizes will
>   	 * be supported ;-) */
> @@ -519,7 +520,7 @@ static int newport_set_font(int unit, const struct console_font *op,
>   	REFCOUNT(new_data) = 0;	/* usage counter */
>   	FNTSUM(new_data) = 0;
>   
> -	p = new_data;
> +	p = (unsigned char *)font_data_buf(new_data);
>   	for (i = 0; i < op->charcount; i++) {
>   		memcpy(p, data, h);
>   		data += 32;
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index 103e91c8d874..8d7840b9ebad 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -1019,8 +1019,10 @@ static const char *fbcon_startup(void)
>   						info->pixmap.blit_y);
>   		vc->vc_font.width = font->width;
>   		vc->vc_font.height = font->height;
> -		vc->vc_font.data = (void *)(p->fontdata = font->data);
> +		vc->vc_font.data = font_data_buf(font->data);
>   		vc->vc_font.charcount = font->charcount;
> +
> +		p->fontdata = font->data;
>   	}
>   
>   	cols = FBCON_SWAP(par->rotate, info->var.xres, info->var.yres);
> @@ -1078,11 +1080,12 @@ static void fbcon_init(struct vc_data *vc, bool init)
>   		if (t->fontdata) {
>   			struct vc_data *fvc = vc_cons[fg_console].d;
>   
> -			vc->vc_font.data = (void *)(p->fontdata =
> -						    fvc->vc_font.data);
> +			vc->vc_font.data = fvc->vc_font.data;
>   			vc->vc_font.width = fvc->vc_font.width;
>   			vc->vc_font.height = fvc->vc_font.height;
>   			vc->vc_font.charcount = fvc->vc_font.charcount;
> +
> +			p->fontdata = t->fontdata;
>   			p->userfont = t->userfont;
>   
>   			if (p->userfont)
> @@ -1097,8 +1100,10 @@ static void fbcon_init(struct vc_data *vc, bool init)
>   							info->pixmap.blit_y);
>   			vc->vc_font.width = font->width;
>   			vc->vc_font.height = font->height;
> -			vc->vc_font.data = (void *)(p->fontdata = font->data);
> +			vc->vc_font.data = font_data_buf(font->data);
>   			vc->vc_font.charcount = font->charcount;
> +
> +			p->fontdata = font->data;
>   		}
>   	}
>   
> @@ -1409,11 +1414,12 @@ static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
>   	svc = *default_mode;
>   	t = &fb_display[svc->vc_num];
>   
> -	if (!vc->vc_font.data) {
> -		vc->vc_font.data = (void *)(p->fontdata = t->fontdata);
> +	if (!p->fontdata) {
> +		vc->vc_font.data = font_data_buf(t->fontdata);
>   		vc->vc_font.width = (*default_mode)->vc_font.width;
>   		vc->vc_font.height = (*default_mode)->vc_font.height;
>   		vc->vc_font.charcount = (*default_mode)->vc_font.charcount;
> +		p->fontdata = t->fontdata;
>   		p->userfont = t->userfont;
>   		if (p->userfont)
>   			REFCOUNT(p->fontdata)++;
> @@ -2047,7 +2053,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
>   	struct fb_var_screeninfo var = info->var;
>   	int x_diff, y_diff, virt_w, virt_h, virt_fw, virt_fh;
>   
> -	if (p->userfont && FNTSIZE(vc->vc_font.data)) {
> +	if (p->userfont && FNTSIZE(p->fontdata)) {
>   		unsigned int size = vc_font_size(&vc->vc_font);
>   
>   		/*
> @@ -2057,7 +2063,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
>   		 * charcount can change and cannot be used to determine the
>   		 * font data allocated size.
>   		 */
> -		if (!size || size > FNTSIZE(vc->vc_font.data))
> +		if (!size || size > FNTSIZE(p->fontdata))
>   			return -EINVAL;
>   	}
>   
> @@ -2281,7 +2287,8 @@ static bool fbcon_blank(struct vc_data *vc, enum vesa_blank_mode blank,
>   
>   static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigned int vpitch)
>   {
> -	const u8 *fontdata = vc->vc_font.data;
> +	struct fbcon_display *p = &fb_display[vc->vc_num];
> +	font_data_t *fontdata = p->fontdata;
>   	u8 *data = font->data;
>   	int i, j;
>   
> @@ -2406,16 +2413,18 @@ static void set_vc_hi_font(struct vc_data *vc, bool set)
>   }
>   
>   static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
> -			     const u8 * data, int userfont)
> +			     font_data_t *data, int userfont)
>   {
>   	struct fb_info *info = fbcon_info_from_console(vc->vc_num);
>   	struct fbcon_par *par = info->fbcon_par;
>   	struct fbcon_display *p = &fb_display[vc->vc_num];
>   	int resize, ret, old_userfont, old_width, old_height, old_charcount;
> +	font_data_t *old_fontdata = p->fontdata;
>   	const u8 *old_data = vc->vc_font.data;
>   
>   	resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
> -	vc->vc_font.data = (void *)(p->fontdata = data);
> +	p->fontdata = data;
> +	vc->vc_font.data = font_data_buf(p->fontdata);
>   	old_userfont = p->userfont;
>   	if ((p->userfont = userfont))
>   		REFCOUNT(data)++;
> @@ -2448,12 +2457,12 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
>   		update_screen(vc);
>   	}
>   
> -	if (old_userfont && (--REFCOUNT(old_data) == 0))
> -		kfree(old_data - FONT_EXTRA_WORDS * sizeof(int));
> +	if (old_userfont && (--REFCOUNT(old_fontdata) == 0))
> +		kfree(old_fontdata - FONT_EXTRA_WORDS * sizeof(int));
>   	return 0;
>   
>   err_out:
> -	p->fontdata = old_data;
> +	p->fontdata = old_fontdata;
>   	vc->vc_font.data = old_data;
>   
>   	if (userfont) {
> @@ -2483,7 +2492,8 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
>   	int h = font->height;
>   	int size, alloc_size;
>   	int i, csum;
> -	u8 *new_data, *data = font->data;
> +	font_data_t *new_data;
> +	u8 *data = font->data;
>   	int pitch = PITCH(font->width);
>   
>   	/* Is there a reason why fbconsole couldn't handle any charcount >256?
> @@ -2522,13 +2532,13 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
>   	if (!new_data)
>   		return -ENOMEM;
>   
> -	memset(new_data, 0, FONT_EXTRA_WORDS * sizeof(int));
> +	memset((u8 *)new_data, 0, FONT_EXTRA_WORDS * sizeof(int));
>   
>   	new_data += FONT_EXTRA_WORDS * sizeof(int);
>   	FNTSIZE(new_data) = size;
>   	REFCOUNT(new_data) = 0;	/* usage counter */
>   	for (i=0; i< charcount; i++) {
> -		memcpy(new_data + i*h*pitch, data +  i*vpitch*pitch, h*pitch);
> +		memcpy((u8 *)new_data + i * h * pitch, data + i * vpitch * pitch, h * pitch);
>   	}
>   
>   	/* Since linux has a nice crc32 function use it for counting font
> diff --git a/drivers/video/fbdev/core/fbcon.h b/drivers/video/fbdev/core/fbcon.h
> index 3f4386a40237..d26ee7860cf5 100644
> --- a/drivers/video/fbdev/core/fbcon.h
> +++ b/drivers/video/fbdev/core/fbcon.h
> @@ -11,6 +11,7 @@
>   #ifndef _VIDEO_FBCON_H
>   #define _VIDEO_FBCON_H
>   
> +#include <linux/font.h>
>   #include <linux/types.h>
>   #include <linux/vt_buffer.h>
>   #include <linux/vt_kern.h>
> @@ -25,7 +26,7 @@
>   
>   struct fbcon_display {
>       /* Filled in by the low-level console driver */
> -    const u_char *fontdata;
> +    font_data_t *fontdata;
>       int userfont;                   /* != 0 if fontdata kmalloc()ed */
>   #ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
>       u_short scrollmode;             /* Scroll Method, use fb_scrollmode() */
> diff --git a/include/linux/font.h b/include/linux/font.h
> index d929c5fa32ca..f19abd112c18 100644
> --- a/include/linux/font.h
> +++ b/include/linux/font.h
> @@ -13,12 +13,57 @@
>   
>   #include <linux/types.h>
>   
> +/*
> + * font_data_t and helpers
> + */
> +
> +/**
> + * font_data_t - Raw font data
> + *
> + * Values of type font_data_t store a pointer to raw font data. The format
> + * is monochrome. Each bit sets a pixel of a stored glyph. Font data does
> + * not store geometry information for the individual glyphs. Users of the
> + * font have to store glyph size, pitch and characer count separately.
> + *
> + * Font data in font_data_t is not equivalent to raw u8. Each pointer stores
> + * an additional hidden header before the fotn data. The layout is

typo: fotn -> font


>   struct font_desc {
>       int idx;
>       const char *name;
>       unsigned int width, height;
>       unsigned int charcount;

FYI - maybe type of width, height, charcount would need update here if it's
changed as I proposed in the other patch?

Helge

Re: [PATCH v2 07/13] lib/fonts: Store font data as font_data_t; update consoles

[Thomas Zimmermann]

Hi

Am 03.03.26 um 15:57 schrieb Helge Deller:
> On 3/2/26 15:08, Thomas Zimmermann wrote:
>> Store font data as pointer to font_data_t instead of unsigned char.
>> Update consoles.
>>
>> Pointers to font data refer to the raw data. There is a hidden header
>> before the data that contains additional state. Document the existing
>> layout and semantics of font_data_t.
>>
>> The data field in struct vc_font can be used by any console. Therefore
>> it still points to plain data without the additional header. Fbcon sets
>> its value from struct fbcon_display.fontdata. Hence, update the size
>> test in fbcon_resize() to use struct fbcon_display.fontdata instead of
>> struct vc_font.data.
>>
>> v2:
>> - 'Font lookup' -> 'Font description' in <linux/font.h>
>>
>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
>> ---
>>   drivers/video/console/newport_con.c | 17 ++++++-----
>>   drivers/video/fbdev/core/fbcon.c    | 44 ++++++++++++++++-----------
>>   drivers/video/fbdev/core/fbcon.h    |  3 +-
>>   include/linux/font.h                | 47 ++++++++++++++++++++++++++++-
>>   4 files changed, 84 insertions(+), 27 deletions(-)
>>
>> diff --git a/drivers/video/console/newport_con.c 
>> b/drivers/video/console/newport_con.c
>> index e2922caa8685..9b9ed1940404 100644
>> --- a/drivers/video/console/newport_con.c
>> +++ b/drivers/video/console/newport_con.c
>> @@ -33,9 +33,9 @@
>>     #define NEWPORT_LEN    0x10000
>>   -#define FONT_DATA ((unsigned char *)font_vga_8x16.data)
>> +#define FONT_DATA font_vga_8x16.data
>>   -static unsigned char *font_data[MAX_NR_CONSOLES];
>> +static font_data_t *font_data[MAX_NR_CONSOLES];
>>     static struct newport_regs *npregs;
>>   static unsigned long newport_addr;
>> @@ -370,9 +370,9 @@ static void newport_clear(struct vc_data *vc, 
>> unsigned int sy, unsigned int sx,
>>   static void newport_putc(struct vc_data *vc, u16 charattr, unsigned 
>> int ypos,
>>                unsigned int xpos)
>>   {
>> -    unsigned char *p;
>> +    const unsigned char *p;
>>   -    p = &font_data[vc->vc_num][(charattr & 0xff) << 4];
>> +    p = &font_data_buf(font_data[vc->vc_num])[(charattr & 0xff) << 4];
>>       charattr = (charattr >> 8) & 0xff;
>>       xpos <<= 3;
>>       ypos <<= 4;
>> @@ -400,7 +400,7 @@ static void newport_putcs(struct vc_data *vc, 
>> const u16 *s,
>>                 unsigned int count, unsigned int ypos,
>>                 unsigned int xpos)
>>   {
>> -    unsigned char *p;
>> +    const unsigned char *p;
>>       unsigned int i;
>>       u16 charattr;
>>   @@ -424,7 +424,7 @@ static void newport_putcs(struct vc_data *vc, 
>> const u16 *s,
>>                    NPORT_DMODE0_L32);
>>         for (i = 0; i < count; i++, xpos += 8) {
>> -        p = &font_data[vc->vc_num][(scr_readw(s++) & 0xff) << 4];
>> +        p = &font_data_buf(font_data[vc->vc_num])[(scr_readw(s++) & 
>> 0xff) << 4];
>>             newport_wait(npregs);
>>   @@ -503,7 +503,8 @@ static int newport_set_font(int unit, const 
>> struct console_font *op,
>>       int h = op->height;
>>       int size = h * op->charcount;
>>       int i;
>> -    unsigned char *new_data, *data = op->data, *p;
>> +    font_data_t *new_data;
>> +    unsigned char *data = op->data, *p;
>>         /* ladis: when I grow up, there will be a day... and more 
>> sizes will
>>        * be supported ;-) */
>> @@ -519,7 +520,7 @@ static int newport_set_font(int unit, const 
>> struct console_font *op,
>>       REFCOUNT(new_data) = 0;    /* usage counter */
>>       FNTSUM(new_data) = 0;
>>   -    p = new_data;
>> +    p = (unsigned char *)font_data_buf(new_data);
>>       for (i = 0; i < op->charcount; i++) {
>>           memcpy(p, data, h);
>>           data += 32;
>> diff --git a/drivers/video/fbdev/core/fbcon.c 
>> b/drivers/video/fbdev/core/fbcon.c
>> index 103e91c8d874..8d7840b9ebad 100644
>> --- a/drivers/video/fbdev/core/fbcon.c
>> +++ b/drivers/video/fbdev/core/fbcon.c
>> @@ -1019,8 +1019,10 @@ static const char *fbcon_startup(void)
>>                           info->pixmap.blit_y);
>>           vc->vc_font.width = font->width;
>>           vc->vc_font.height = font->height;
>> -        vc->vc_font.data = (void *)(p->fontdata = font->data);
>> +        vc->vc_font.data = font_data_buf(font->data);
>>           vc->vc_font.charcount = font->charcount;
>> +
>> +        p->fontdata = font->data;
>>       }
>>         cols = FBCON_SWAP(par->rotate, info->var.xres, info->var.yres);
>> @@ -1078,11 +1080,12 @@ static void fbcon_init(struct vc_data *vc, 
>> bool init)
>>           if (t->fontdata) {
>>               struct vc_data *fvc = vc_cons[fg_console].d;
>>   -            vc->vc_font.data = (void *)(p->fontdata =
>> -                            fvc->vc_font.data);
>> +            vc->vc_font.data = fvc->vc_font.data;
>>               vc->vc_font.width = fvc->vc_font.width;
>>               vc->vc_font.height = fvc->vc_font.height;
>>               vc->vc_font.charcount = fvc->vc_font.charcount;
>> +
>> +            p->fontdata = t->fontdata;
>>               p->userfont = t->userfont;
>>                 if (p->userfont)
>> @@ -1097,8 +1100,10 @@ static void fbcon_init(struct vc_data *vc, 
>> bool init)
>>                               info->pixmap.blit_y);
>>               vc->vc_font.width = font->width;
>>               vc->vc_font.height = font->height;
>> -            vc->vc_font.data = (void *)(p->fontdata = font->data);
>> +            vc->vc_font.data = font_data_buf(font->data);
>>               vc->vc_font.charcount = font->charcount;
>> +
>> +            p->fontdata = font->data;
>>           }
>>       }
>>   @@ -1409,11 +1414,12 @@ static void fbcon_set_disp(struct fb_info 
>> *info, struct fb_var_screeninfo *var,
>>       svc = *default_mode;
>>       t = &fb_display[svc->vc_num];
>>   -    if (!vc->vc_font.data) {
>> -        vc->vc_font.data = (void *)(p->fontdata = t->fontdata);
>> +    if (!p->fontdata) {
>> +        vc->vc_font.data = font_data_buf(t->fontdata);
>>           vc->vc_font.width = (*default_mode)->vc_font.width;
>>           vc->vc_font.height = (*default_mode)->vc_font.height;
>>           vc->vc_font.charcount = (*default_mode)->vc_font.charcount;
>> +        p->fontdata = t->fontdata;
>>           p->userfont = t->userfont;
>>           if (p->userfont)
>>               REFCOUNT(p->fontdata)++;
>> @@ -2047,7 +2053,7 @@ static int fbcon_resize(struct vc_data *vc, 
>> unsigned int width,
>>       struct fb_var_screeninfo var = info->var;
>>       int x_diff, y_diff, virt_w, virt_h, virt_fw, virt_fh;
>>   -    if (p->userfont && FNTSIZE(vc->vc_font.data)) {
>> +    if (p->userfont && FNTSIZE(p->fontdata)) {
>>           unsigned int size = vc_font_size(&vc->vc_font);
>>             /*
>> @@ -2057,7 +2063,7 @@ static int fbcon_resize(struct vc_data *vc, 
>> unsigned int width,
>>            * charcount can change and cannot be used to determine the
>>            * font data allocated size.
>>            */
>> -        if (!size || size > FNTSIZE(vc->vc_font.data))
>> +        if (!size || size > FNTSIZE(p->fontdata))
>>               return -EINVAL;
>>       }
>>   @@ -2281,7 +2287,8 @@ static bool fbcon_blank(struct vc_data *vc, 
>> enum vesa_blank_mode blank,
>>     static int fbcon_get_font(struct vc_data *vc, struct console_font 
>> *font, unsigned int vpitch)
>>   {
>> -    const u8 *fontdata = vc->vc_font.data;
>> +    struct fbcon_display *p = &fb_display[vc->vc_num];
>> +    font_data_t *fontdata = p->fontdata;
>>       u8 *data = font->data;
>>       int i, j;
>>   @@ -2406,16 +2413,18 @@ static void set_vc_hi_font(struct vc_data 
>> *vc, bool set)
>>   }
>>     static int fbcon_do_set_font(struct vc_data *vc, int w, int h, 
>> int charcount,
>> -                 const u8 * data, int userfont)
>> +                 font_data_t *data, int userfont)
>>   {
>>       struct fb_info *info = fbcon_info_from_console(vc->vc_num);
>>       struct fbcon_par *par = info->fbcon_par;
>>       struct fbcon_display *p = &fb_display[vc->vc_num];
>>       int resize, ret, old_userfont, old_width, old_height, 
>> old_charcount;
>> +    font_data_t *old_fontdata = p->fontdata;
>>       const u8 *old_data = vc->vc_font.data;
>>         resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
>> -    vc->vc_font.data = (void *)(p->fontdata = data);
>> +    p->fontdata = data;
>> +    vc->vc_font.data = font_data_buf(p->fontdata);
>>       old_userfont = p->userfont;
>>       if ((p->userfont = userfont))
>>           REFCOUNT(data)++;
>> @@ -2448,12 +2457,12 @@ static int fbcon_do_set_font(struct vc_data 
>> *vc, int w, int h, int charcount,
>>           update_screen(vc);
>>       }
>>   -    if (old_userfont && (--REFCOUNT(old_data) == 0))
>> -        kfree(old_data - FONT_EXTRA_WORDS * sizeof(int));
>> +    if (old_userfont && (--REFCOUNT(old_fontdata) == 0))
>> +        kfree(old_fontdata - FONT_EXTRA_WORDS * sizeof(int));
>>       return 0;
>>     err_out:
>> -    p->fontdata = old_data;
>> +    p->fontdata = old_fontdata;
>>       vc->vc_font.data = old_data;
>>         if (userfont) {
>> @@ -2483,7 +2492,8 @@ static int fbcon_set_font(struct vc_data *vc, 
>> const struct console_font *font,
>>       int h = font->height;
>>       int size, alloc_size;
>>       int i, csum;
>> -    u8 *new_data, *data = font->data;
>> +    font_data_t *new_data;
>> +    u8 *data = font->data;
>>       int pitch = PITCH(font->width);
>>         /* Is there a reason why fbconsole couldn't handle any 
>> charcount >256?
>> @@ -2522,13 +2532,13 @@ static int fbcon_set_font(struct vc_data *vc, 
>> const struct console_font *font,
>>       if (!new_data)
>>           return -ENOMEM;
>>   -    memset(new_data, 0, FONT_EXTRA_WORDS * sizeof(int));
>> +    memset((u8 *)new_data, 0, FONT_EXTRA_WORDS * sizeof(int));
>>         new_data += FONT_EXTRA_WORDS * sizeof(int);
>>       FNTSIZE(new_data) = size;
>>       REFCOUNT(new_data) = 0;    /* usage counter */
>>       for (i=0; i< charcount; i++) {
>> -        memcpy(new_data + i*h*pitch, data +  i*vpitch*pitch, h*pitch);
>> +        memcpy((u8 *)new_data + i * h * pitch, data + i * vpitch * 
>> pitch, h * pitch);
>>       }
>>         /* Since linux has a nice crc32 function use it for counting 
>> font
>> diff --git a/drivers/video/fbdev/core/fbcon.h 
>> b/drivers/video/fbdev/core/fbcon.h
>> index 3f4386a40237..d26ee7860cf5 100644
>> --- a/drivers/video/fbdev/core/fbcon.h
>> +++ b/drivers/video/fbdev/core/fbcon.h
>> @@ -11,6 +11,7 @@
>>   #ifndef _VIDEO_FBCON_H
>>   #define _VIDEO_FBCON_H
>>   +#include <linux/font.h>
>>   #include <linux/types.h>
>>   #include <linux/vt_buffer.h>
>>   #include <linux/vt_kern.h>
>> @@ -25,7 +26,7 @@
>>     struct fbcon_display {
>>       /* Filled in by the low-level console driver */
>> -    const u_char *fontdata;
>> +    font_data_t *fontdata;
>>       int userfont;                   /* != 0 if fontdata kmalloc()ed */
>>   #ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
>>       u_short scrollmode;             /* Scroll Method, use 
>> fb_scrollmode() */
>> diff --git a/include/linux/font.h b/include/linux/font.h
>> index d929c5fa32ca..f19abd112c18 100644
>> --- a/include/linux/font.h
>> +++ b/include/linux/font.h
>> @@ -13,12 +13,57 @@
>>     #include <linux/types.h>
>>   +/*
>> + * font_data_t and helpers
>> + */
>> +
>> +/**
>> + * font_data_t - Raw font data
>> + *
>> + * Values of type font_data_t store a pointer to raw font data. The 
>> format
>> + * is monochrome. Each bit sets a pixel of a stored glyph. Font data 
>> does
>> + * not store geometry information for the individual glyphs. Users 
>> of the
>> + * font have to store glyph size, pitch and characer count separately.
>> + *
>> + * Font data in font_data_t is not equivalent to raw u8. Each 
>> pointer stores
>> + * an additional hidden header before the fotn data. The layout is
>
> typo: fotn -> font
>
>
>>   struct font_desc {
>>       int idx;
>>       const char *name;
>>       unsigned int width, height;
>>       unsigned int charcount;
>
> FYI - maybe type of width, height, charcount would need update here if 
> it's
> changed as I proposed in the other patch?

There are places like [1] that use font_desc and I honestly don't dare 
touching this code.

[1] 
https://elixir.bootlin.com/linux/v6.19.3/source/arch/m68k/kernel/asm-offsets.c#L83

Best regards
Thomas

>
> Helge

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)

[PATCH v2 08/13] lib/fonts: Read font size with font_data_size()

[Thomas Zimmermann]

Add font_data_size() and update consoles to use it.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/console/newport_con.c |  2 +-
 drivers/video/fbdev/core/fbcon.c    | 14 +++++++-------
 include/linux/font.h                |  2 ++
 lib/fonts/fonts.c                   | 21 +++++++++++++++++++++
 4 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index 9b9ed1940404..1198c6bc2777 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -530,7 +530,7 @@ static int newport_set_font(int unit, const struct console_font *op,
 	/* check if font is already used by other console */
 	for (i = 0; i < MAX_NR_CONSOLES; i++) {
 		if (font_data[i] != FONT_DATA
-		    && FNTSIZE(font_data[i]) == size
+		    && font_data_size(font_data[i]) == size
 		    && !memcmp(font_data[i], new_data, size)) {
 			kfree(new_data - FONT_EXTRA_WORDS * sizeof(int));
 			/* current font is the same as the new one */
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 8d7840b9ebad..fa8f3e4196de 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -2053,7 +2053,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
 	struct fb_var_screeninfo var = info->var;
 	int x_diff, y_diff, virt_w, virt_h, virt_fw, virt_fh;
 
-	if (p->userfont && FNTSIZE(p->fontdata)) {
+	if (p->userfont && font_data_size(p->fontdata)) {
 		unsigned int size = vc_font_size(&vc->vc_font);
 
 		/*
@@ -2063,7 +2063,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
 		 * charcount can change and cannot be used to determine the
 		 * font data allocated size.
 		 */
-		if (!size || size > FNTSIZE(p->fontdata))
+		if (!size || size > font_data_size(p->fontdata))
 			return -EINVAL;
 	}
 
@@ -2302,7 +2302,7 @@ static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigne
 
 	if (font->width <= 8) {
 		j = vc->vc_font.height;
-		if (font->charcount * j > FNTSIZE(fontdata))
+		if (font->charcount * j > font_data_size(fontdata))
 			return -EINVAL;
 
 		for (i = 0; i < font->charcount; i++) {
@@ -2313,7 +2313,7 @@ static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigne
 		}
 	} else if (font->width <= 16) {
 		j = vc->vc_font.height * 2;
-		if (font->charcount * j > FNTSIZE(fontdata))
+		if (font->charcount * j > font_data_size(fontdata))
 			return -EINVAL;
 
 		for (i = 0; i < font->charcount; i++) {
@@ -2323,7 +2323,7 @@ static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigne
 			fontdata += j;
 		}
 	} else if (font->width <= 24) {
-		if (font->charcount * (vc->vc_font.height * sizeof(u32)) > FNTSIZE(fontdata))
+		if (font->charcount * (vc->vc_font.height * sizeof(u32)) > font_data_size(fontdata))
 			return -EINVAL;
 
 		for (i = 0; i < font->charcount; i++) {
@@ -2338,7 +2338,7 @@ static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigne
 		}
 	} else {
 		j = vc->vc_font.height * 4;
-		if (font->charcount * j > FNTSIZE(fontdata))
+		if (font->charcount * j > font_data_size(fontdata))
 			return -EINVAL;
 
 		for (i = 0; i < font->charcount; i++) {
@@ -2553,7 +2553,7 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 		if (fb_display[i].userfont &&
 		    fb_display[i].fontdata &&
 		    FNTSUM(fb_display[i].fontdata) == csum &&
-		    FNTSIZE(fb_display[i].fontdata) == size &&
+		    font_data_size(fb_display[i].fontdata) == size &&
 		    tmp->vc_font.width == w &&
 		    !memcmp(fb_display[i].fontdata, new_data, size)) {
 			kfree(new_data - FONT_EXTRA_WORDS * sizeof(int));
diff --git a/include/linux/font.h b/include/linux/font.h
index f19abd112c18..55cc016a9357 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -54,6 +54,8 @@ static inline const unsigned char *font_data_buf(font_data_t *fd)
 	return (const unsigned char *)fd;
 }
 
+unsigned int font_data_size(font_data_t *fd);
+
 /*
  * Font description
  */
diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index a7f118b30171..8c9a6762061c 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -20,6 +20,27 @@
 #endif
 #include <linux/font.h>
 
+/*
+ * Helpers for font_data_t
+ */
+
+/**
+ * font_data_size - Return size of the font data in bytes
+ * @fd: Font data
+ *
+ * Returns:
+ * The number of bytes in the given font data.
+ */
+unsigned int font_data_size(font_data_t *fd)
+{
+	return FNTSIZE(fd);
+}
+EXPORT_SYMBOL_GPL(font_data_size);
+
+/*
+ * Font lookup
+ */
+
 static const struct font_desc *fonts[] = {
 #ifdef CONFIG_FONT_8x8
 	&font_vga_8x8,
-- 
2.53.0

[PATCH v2 09/13] lib/fonts: Compare font data for equality with font_data_is_equal()

[Thomas Zimmermann]

Add font_data_is_equal() and update consoles to use it.

Font data is equal if it has the same size and contains the same values
on all bytes. Only fbcon uses a crc32 checksum. If set in both operands
the checksums have to be equal.

The new helper also guarantees to not compare internal fonts against
fonts from user space. Internal fonts cannot be ref-counted, so making
them equal to user-space fonts with the same byte sequence results in
undefined behavior.

The test only compares data buffers. Their interpretation is up each
console. Therefore remove a width test in fbcon_set_font().

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/console/newport_con.c |  3 +--
 drivers/video/fbdev/core/fbcon.c    |  7 +-----
 include/linux/font.h                |  1 +
 lib/fonts/fonts.c                   | 37 +++++++++++++++++++++++++++--
 4 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index 1198c6bc2777..4db2b901c709 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -530,8 +530,7 @@ static int newport_set_font(int unit, const struct console_font *op,
 	/* check if font is already used by other console */
 	for (i = 0; i < MAX_NR_CONSOLES; i++) {
 		if (font_data[i] != FONT_DATA
-		    && font_data_size(font_data[i]) == size
-		    && !memcmp(font_data[i], new_data, size)) {
+		    && font_data_is_equal(font_data[i], new_data)) {
 			kfree(new_data - FONT_EXTRA_WORDS * sizeof(int));
 			/* current font is the same as the new one */
 			if (i == unit)
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index fa8f3e4196de..31e812d87d9e 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -2548,14 +2548,9 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 	FNTSUM(new_data) = csum;
 	/* Check if the same font is on some other console already */
 	for (i = first_fb_vc; i <= last_fb_vc; i++) {
-		struct vc_data *tmp = vc_cons[i].d;
-
 		if (fb_display[i].userfont &&
 		    fb_display[i].fontdata &&
-		    FNTSUM(fb_display[i].fontdata) == csum &&
-		    font_data_size(fb_display[i].fontdata) == size &&
-		    tmp->vc_font.width == w &&
-		    !memcmp(fb_display[i].fontdata, new_data, size)) {
+		    font_data_is_equal(fb_display[i].fontdata, new_data)) {
 			kfree(new_data - FONT_EXTRA_WORDS * sizeof(int));
 			new_data = (u8 *)fb_display[i].fontdata;
 			break;
diff --git a/include/linux/font.h b/include/linux/font.h
index 55cc016a9357..1f5b85601c9b 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -55,6 +55,7 @@ static inline const unsigned char *font_data_buf(font_data_t *fd)
 }
 
 unsigned int font_data_size(font_data_t *fd);
+bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs);
 
 /*
  * Font description
diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index 8c9a6762061c..c9f6328d5dda 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -12,18 +12,25 @@
  * for more details.
  */
 
+#include <linux/font.h>
 #include <linux/module.h>
-#include <linux/types.h>
 #include <linux/string.h>
+#include <linux/types.h>
+
+#include <asm/sections.h>
 #if defined(__mc68000__)
 #include <asm/setup.h>
 #endif
-#include <linux/font.h>
 
 /*
  * Helpers for font_data_t
  */
 
+static bool font_data_is_internal(font_data_t *fd)
+{
+	return is_kernel_rodata((unsigned long)fd);
+}
+
 /**
  * font_data_size - Return size of the font data in bytes
  * @fd: Font data
@@ -37,6 +44,32 @@ unsigned int font_data_size(font_data_t *fd)
 }
 EXPORT_SYMBOL_GPL(font_data_size);
 
+/**
+ * font_data_is_equal - Compares font data for equality
+ * @lhs: Left-hand side font data
+ * @rhs: Right-hand-size font data
+ *
+ * Font data is equal if is constain the same sequence of values. The
+ * helper also use the checksum, if both arguments contain it. Font data
+ * coming from different origins, internal or from user space, is never
+ * equal. Allowing this would break reference counting.
+ *
+ * Returns:
+ * True if the given font data is equal, false otherwise.
+ */
+bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs)
+{
+	if (font_data_is_internal(lhs) != font_data_is_internal(rhs))
+		return false;
+	if (font_data_size(lhs) != font_data_size(rhs))
+		return false;
+	if (FNTSUM(lhs) && FNTSUM(rhs) && FNTSUM(lhs) != FNTSUM(rhs))
+		return false;
+
+	return !memcmp(lhs, rhs, FNTSIZE(lhs));
+}
+EXPORT_SYMBOL_GPL(font_data_is_equal);
+
 /*
  * Font lookup
  */
-- 
2.53.0

Re: [PATCH v2 09/13] lib/fonts: Compare font data for equality with font_data_is_equal()

[Nathan Chancellor]

Hi Thomas,

On Mon, Mar 02, 2026 at 03:08:43PM +0100, Thomas Zimmermann wrote:
...
> diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
> index 8c9a6762061c..c9f6328d5dda 100644
> --- a/lib/fonts/fonts.c
> +++ b/lib/fonts/fonts.c
> @@ -12,18 +12,25 @@
>   * for more details.
>   */
>  
> +#include <linux/font.h>
>  #include <linux/module.h>
> -#include <linux/types.h>
>  #include <linux/string.h>
> +#include <linux/types.h>
> +
> +#include <asm/sections.h>
>  #if defined(__mc68000__)
>  #include <asm/setup.h>
>  #endif
> -#include <linux/font.h>
>  
>  /*
>   * Helpers for font_data_t
>   */
>  
> +static bool font_data_is_internal(font_data_t *fd)
> +{
> +	return is_kernel_rodata((unsigned long)fd);
> +}
> +
>  /**
>   * font_data_size - Return size of the font data in bytes
>   * @fd: Font data
> @@ -37,6 +44,32 @@ unsigned int font_data_size(font_data_t *fd)
>  }
>  EXPORT_SYMBOL_GPL(font_data_size);
>  
> +/**
> + * font_data_is_equal - Compares font data for equality
> + * @lhs: Left-hand side font data
> + * @rhs: Right-hand-size font data
> + *
> + * Font data is equal if is constain the same sequence of values. The
> + * helper also use the checksum, if both arguments contain it. Font data
> + * coming from different origins, internal or from user space, is never
> + * equal. Allowing this would break reference counting.
> + *
> + * Returns:
> + * True if the given font data is equal, false otherwise.
> + */
> +bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs)
> +{
> +	if (font_data_is_internal(lhs) != font_data_is_internal(rhs))
> +		return false;

This breaks the build when CONFIG_FONT_SUPPORT is a module.

  $ cat allno.config
  CONFIG_MODULES=y
  CONFIG_DRM=m
  CONFIG_DRM_PANIC=y

  $ make -skj"$(nproc)" ARCH=x86_64 CROSS_COMPILE=x86_64-linux- KCONFIG_ALLCONFIG=1 allnoconfig all
  ERROR: modpost: "__end_rodata" [lib/fonts/font.ko] undefined!
  make[4]: *** [scripts/Makefile.modpost:147: Module.symvers] Error 1
  ...

  $ scripts/config -s FONT_SUPPORT
  m

Cheers,
Nathan

> +	if (font_data_size(lhs) != font_data_size(rhs))
> +		return false;
> +	if (FNTSUM(lhs) && FNTSUM(rhs) && FNTSUM(lhs) != FNTSUM(rhs))
> +		return false;
> +
> +	return !memcmp(lhs, rhs, FNTSIZE(lhs));
> +}
> +EXPORT_SYMBOL_GPL(font_data_is_equal);
> +
>  /*
>   * Font lookup
>   */
> -- 
> 2.53.0
> 

Re: [PATCH v2 09/13] lib/fonts: Compare font data for equality with font_data_is_equal()

[Thomas Zimmermann]

[-- Attachment #1: Type: text/plain, Size: 1348 bytes --]

Hi

Am 05.03.26 um 01:23 schrieb Nathan Chancellor:
[...]
>>   
>> +static bool font_data_is_internal(font_data_t *fd)
>> +{
>> +	return is_kernel_rodata((unsigned long)fd);
>> +}
>> +
[...]
>>
>> This breaks the build when CONFIG_FONT_SUPPORT is a module.
>>
>>    $ cat allno.config
>>    CONFIG_MODULES=y
>>    CONFIG_DRM=m
>>    CONFIG_DRM_PANIC=y
>>
>>    $ make -skj"$(nproc)" ARCH=x86_64 CROSS_COMPILE=x86_64-linux- KCONFIG_ALLCONFIG=1 allnoconfig all
>>    ERROR: modpost: "__end_rodata" [lib/fonts/font.ko] undefined!
>>    make[4]: *** [scripts/Makefile.modpost:147: Module.symvers] Error 1
>>    ...
>>
>>    $ scripts/config -s FONT_SUPPORT
>>    m

Thanks for testing. The attached patch fixes the problem for me. Could 
you please test?

Best regards
Thomas

>>
>> Cheers,
>> Nathan
>>
>>
>> +	if (font_data_size(lhs) != font_data_size(rhs))
>> +		return false;
>> +	if (FNTSUM(lhs) && FNTSUM(rhs) && FNTSUM(lhs) != FNTSUM(rhs))
>> +		return false;
>> +
>> +	return !memcmp(lhs, rhs, FNTSIZE(lhs));
>> +}
>> +EXPORT_SYMBOL_GPL(font_data_is_equal);
>> +
>>   /*
>>    * Font lookup
>>    */
>> -- 
>> 2.53.0
>>

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)


[-- Attachment #2: 0001-test-for-internal-fonts-by-refcount.patch --]
[-- Type: text/x-patch, Size: 927 bytes --]

From 8dc48d2e676d1437584794f4df3dd20d08878655 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Thu, 5 Mar 2026 09:28:28 +0100
Subject: [PATCH] test for internal fonts by refcount

Internal font data is 'static const'. Hence test against the refcount
being zero.
---
 lib/fonts/fonts.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index 198aae869be2..b73d74b977ec 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -45,14 +45,11 @@ static struct font_data *to_font_data_struct(font_data_t *fd)
 
 static bool font_data_is_internal(font_data_t *fd)
 {
-	return is_kernel_rodata((unsigned long)fd);
+	return !REFCOUNT(fd); /* internal fonts have no reference counting */
 }
 
 static void font_data_free(font_data_t *fd)
 {
-	if (WARN_ON(font_data_is_internal(fd)))
-		return;
-
 	kfree(to_font_data_struct(fd));
 }
 
-- 
2.53.0

Re: [PATCH v2 09/13] lib/fonts: Compare font data for equality with font_data_is_equal()

[Nathan Chancellor]

On Thu, Mar 05, 2026 at 10:31:13AM +0100, Thomas Zimmermann wrote:
> Thanks for testing. The attached patch fixes the problem for me. Could you
> please test?

Yeah, that appears to work for me as well.

Tested-by: Nathan Chancellor <nathan@kernel.org> # build

It seems like the asm/sections.h include can be dropped as well, since
that was only included for is_kernel_rodata() AFAICT.

> From 8dc48d2e676d1437584794f4df3dd20d08878655 Mon Sep 17 00:00:00 2001
> From: Thomas Zimmermann <tzimmermann@suse.de>
> Date: Thu, 5 Mar 2026 09:28:28 +0100
> Subject: [PATCH] test for internal fonts by refcount
> 
> Internal font data is 'static const'. Hence test against the refcount
> being zero.
> ---
>  lib/fonts/fonts.c | 5 +----
>  1 file changed, 1 insertion(+), 4 deletions(-)
> 
> diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
> index 198aae869be2..b73d74b977ec 100644
> --- a/lib/fonts/fonts.c
> +++ b/lib/fonts/fonts.c
> @@ -45,14 +45,11 @@ static struct font_data *to_font_data_struct(font_data_t *fd)
>  
>  static bool font_data_is_internal(font_data_t *fd)
>  {
> -	return is_kernel_rodata((unsigned long)fd);
> +	return !REFCOUNT(fd); /* internal fonts have no reference counting */
>  }
>  
>  static void font_data_free(font_data_t *fd)
>  {
> -	if (WARN_ON(font_data_is_internal(fd)))
> -		return;
> -
>  	kfree(to_font_data_struct(fd));
>  }
>  
> -- 
> 2.53.0
> 

[PATCH v2 10/13] lib/fonts: Manage font-data lifetime with font_data_get/_put()

[Thomas Zimmermann]

Add font_data_get() and font_data_put(). Update consoles to use them
over REFCOUNT() and plain kfree().

Newly allocated font data starts with a reference count of 1. Loading
the font puts the previously loaded font. If the reference count reaches
zero, font_data_put() frees the font data.

The kernel stores internal font data in a read-only section. Invoking
font_data_get() and font_data_put() tests this internally and returns
success without further operation. From the caller's perspective,
getting and putting works the same for all font data.

Fbcon used the userfont flag distinguish between internal fonts and
fonts loaded by user space. Only the latter where refcounted. With the
new helper's automatic handling of internal font data, remove the
userfont flag from fbcon.

Newport_con uses a default font, FONT_DATA, until user space loads
custom font data. Remove all special cases for FONT_DATA, as the get
and put calls' read-only handlign also covers this case.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/console/newport_con.c | 26 ++++-------
 drivers/video/fbdev/core/fbcon.c    | 65 +++++++++++++--------------
 drivers/video/fbdev/core/fbcon.h    |  1 -
 include/linux/font.h                |  2 +
 lib/fonts/fonts.c                   | 70 +++++++++++++++++++++++++++++
 5 files changed, 111 insertions(+), 53 deletions(-)

diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index 4db2b901c709..1bc3cb1ea116 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -517,7 +517,7 @@ static int newport_set_font(int unit, const struct console_font *op,
 
 	new_data += FONT_EXTRA_WORDS * sizeof(int);
 	FNTSIZE(new_data) = size;
-	REFCOUNT(new_data) = 0;	/* usage counter */
+	REFCOUNT(new_data) = 1;	/* usage counter */
 	FNTSUM(new_data) = 0;
 
 	p = (unsigned char *)font_data_buf(new_data);
@@ -529,23 +529,18 @@ static int newport_set_font(int unit, const struct console_font *op,
 
 	/* check if font is already used by other console */
 	for (i = 0; i < MAX_NR_CONSOLES; i++) {
-		if (font_data[i] != FONT_DATA
-		    && font_data_is_equal(font_data[i], new_data)) {
-			kfree(new_data - FONT_EXTRA_WORDS * sizeof(int));
+		if (font_data_is_equal(font_data[i], new_data)) {
+			font_data_put(new_data);
 			/* current font is the same as the new one */
 			if (i == unit)
 				return 0;
 			new_data = font_data[i];
+			font_data_get(new_data);
 			break;
 		}
 	}
-	/* old font is user font */
-	if (font_data[unit] != FONT_DATA) {
-		if (--REFCOUNT(font_data[unit]) == 0)
-			kfree(font_data[unit] -
-			      FONT_EXTRA_WORDS * sizeof(int));
-	}
-	REFCOUNT(new_data)++;
+
+	font_data_put(font_data[unit]);
 	font_data[unit] = new_data;
 
 	return 0;
@@ -553,12 +548,9 @@ static int newport_set_font(int unit, const struct console_font *op,
 
 static int newport_set_def_font(int unit, struct console_font *op)
 {
-	if (font_data[unit] != FONT_DATA) {
-		if (--REFCOUNT(font_data[unit]) == 0)
-			kfree(font_data[unit] -
-			      FONT_EXTRA_WORDS * sizeof(int));
-		font_data[unit] = FONT_DATA;
-	}
+	font_data_put(font_data[unit]);
+	font_data[unit] = FONT_DATA;
+	font_data_get(font_data[unit]);
 
 	return 0;
 }
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 31e812d87d9e..00255ac92e42 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -1023,6 +1023,7 @@ static const char *fbcon_startup(void)
 		vc->vc_font.charcount = font->charcount;
 
 		p->fontdata = font->data;
+		font_data_get(p->fontdata);
 	}
 
 	cols = FBCON_SWAP(par->rotate, info->var.xres, info->var.yres);
@@ -1086,10 +1087,7 @@ static void fbcon_init(struct vc_data *vc, bool init)
 			vc->vc_font.charcount = fvc->vc_font.charcount;
 
 			p->fontdata = t->fontdata;
-			p->userfont = t->userfont;
-
-			if (p->userfont)
-				REFCOUNT(p->fontdata)++;
+			font_data_get(p->fontdata);
 		} else {
 			const struct font_desc *font = NULL;
 
@@ -1104,6 +1102,7 @@ static void fbcon_init(struct vc_data *vc, bool init)
 			vc->vc_font.charcount = font->charcount;
 
 			p->fontdata = font->data;
+			font_data_get(p->fontdata);
 		}
 	}
 
@@ -1194,10 +1193,10 @@ static void fbcon_init(struct vc_data *vc, bool init)
 
 static void fbcon_free_font(struct fbcon_display *p)
 {
-	if (p->userfont && p->fontdata && (--REFCOUNT(p->fontdata) == 0))
-		kfree(p->fontdata - FONT_EXTRA_WORDS * sizeof(int));
-	p->fontdata = NULL;
-	p->userfont = 0;
+	if (p->fontdata) {
+		font_data_put(p->fontdata);
+		p->fontdata = NULL;
+	}
 }
 
 static void set_vc_hi_font(struct vc_data *vc, bool set);
@@ -1420,9 +1419,7 @@ static void fbcon_set_disp(struct fb_info *info, struct fb_var_screeninfo *var,
 		vc->vc_font.height = (*default_mode)->vc_font.height;
 		vc->vc_font.charcount = (*default_mode)->vc_font.charcount;
 		p->fontdata = t->fontdata;
-		p->userfont = t->userfont;
-		if (p->userfont)
-			REFCOUNT(p->fontdata)++;
+		font_data_get(p->fontdata);
 	}
 
 	var->activate = FB_ACTIVATE_NOW;
@@ -2053,7 +2050,7 @@ static int fbcon_resize(struct vc_data *vc, unsigned int width,
 	struct fb_var_screeninfo var = info->var;
 	int x_diff, y_diff, virt_w, virt_h, virt_fw, virt_fh;
 
-	if (p->userfont && font_data_size(p->fontdata)) {
+	if (font_data_size(p->fontdata)) {
 		unsigned int size = vc_font_size(&vc->vc_font);
 
 		/*
@@ -2413,21 +2410,20 @@ static void set_vc_hi_font(struct vc_data *vc, bool set)
 }
 
 static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
-			     font_data_t *data, int userfont)
+			     font_data_t *data)
 {
 	struct fb_info *info = fbcon_info_from_console(vc->vc_num);
 	struct fbcon_par *par = info->fbcon_par;
 	struct fbcon_display *p = &fb_display[vc->vc_num];
-	int resize, ret, old_userfont, old_width, old_height, old_charcount;
+	int resize, ret, old_width, old_height, old_charcount;
 	font_data_t *old_fontdata = p->fontdata;
 	const u8 *old_data = vc->vc_font.data;
 
+	font_data_get(data);
+
 	resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
 	p->fontdata = data;
 	vc->vc_font.data = font_data_buf(p->fontdata);
-	old_userfont = p->userfont;
-	if ((p->userfont = userfont))
-		REFCOUNT(data)++;
 
 	old_width = vc->vc_font.width;
 	old_height = vc->vc_font.height;
@@ -2457,24 +2453,20 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
 		update_screen(vc);
 	}
 
-	if (old_userfont && (--REFCOUNT(old_fontdata) == 0))
-		kfree(old_fontdata - FONT_EXTRA_WORDS * sizeof(int));
+	if (old_fontdata)
+		font_data_put(old_fontdata);
+
 	return 0;
 
 err_out:
 	p->fontdata = old_fontdata;
 	vc->vc_font.data = old_data;
-
-	if (userfont) {
-		p->userfont = old_userfont;
-		if (--REFCOUNT(data) == 0)
-			kfree(data - FONT_EXTRA_WORDS * sizeof(int));
-	}
-
 	vc->vc_font.width = old_width;
 	vc->vc_font.height = old_height;
 	vc->vc_font.charcount = old_charcount;
 
+	font_data_put(data);
+
 	return ret;
 }
 
@@ -2491,9 +2483,9 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 	int w = font->width;
 	int h = font->height;
 	int size, alloc_size;
-	int i, csum;
+	int i, csum, ret;
 	font_data_t *new_data;
-	u8 *data = font->data;
+	const u8 *data = font->data;
 	int pitch = PITCH(font->width);
 
 	/* Is there a reason why fbconsole couldn't handle any charcount >256?
@@ -2536,7 +2528,7 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 
 	new_data += FONT_EXTRA_WORDS * sizeof(int);
 	FNTSIZE(new_data) = size;
-	REFCOUNT(new_data) = 0;	/* usage counter */
+	REFCOUNT(new_data) = 1;	/* usage counter */
 	for (i=0; i< charcount; i++) {
 		memcpy((u8 *)new_data + i * h * pitch, data + i * vpitch * pitch, h * pitch);
 	}
@@ -2548,15 +2540,18 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 	FNTSUM(new_data) = csum;
 	/* Check if the same font is on some other console already */
 	for (i = first_fb_vc; i <= last_fb_vc; i++) {
-		if (fb_display[i].userfont &&
-		    fb_display[i].fontdata &&
+		if (fb_display[i].fontdata &&
 		    font_data_is_equal(fb_display[i].fontdata, new_data)) {
-			kfree(new_data - FONT_EXTRA_WORDS * sizeof(int));
-			new_data = (u8 *)fb_display[i].fontdata;
+			font_data_get(fb_display[i].fontdata);
+			font_data_put(new_data);
+			new_data = fb_display[i].fontdata;
 			break;
 		}
 	}
-	return fbcon_do_set_font(vc, font->width, font->height, charcount, new_data, 1);
+	ret = fbcon_do_set_font(vc, font->width, font->height, charcount, new_data);
+	font_data_put(new_data);
+
+	return ret;
 }
 
 static int fbcon_set_def_font(struct vc_data *vc, struct console_font *font,
@@ -2573,7 +2568,7 @@ static int fbcon_set_def_font(struct vc_data *vc, struct console_font *font,
 
 	font->width = f->width;
 	font->height = f->height;
-	return fbcon_do_set_font(vc, f->width, f->height, f->charcount, f->data, 0);
+	return fbcon_do_set_font(vc, f->width, f->height, f->charcount, f->data);
 }
 
 static u16 palette_red[16];
diff --git a/drivers/video/fbdev/core/fbcon.h b/drivers/video/fbdev/core/fbcon.h
index d26ee7860cf5..1e3c1ef84762 100644
--- a/drivers/video/fbdev/core/fbcon.h
+++ b/drivers/video/fbdev/core/fbcon.h
@@ -27,7 +27,6 @@
 struct fbcon_display {
     /* Filled in by the low-level console driver */
     font_data_t *fontdata;
-    int userfont;                   /* != 0 if fontdata kmalloc()ed */
 #ifdef CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION
     u_short scrollmode;             /* Scroll Method, use fb_scrollmode() */
 #endif
diff --git a/include/linux/font.h b/include/linux/font.h
index 1f5b85601c9b..a8610201afb7 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -54,6 +54,8 @@ static inline const unsigned char *font_data_buf(font_data_t *fd)
 	return (const unsigned char *)fd;
 }
 
+void font_data_get(font_data_t *fd);
+bool font_data_put(font_data_t *fd);
 unsigned int font_data_size(font_data_t *fd);
 bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs);
 
diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index c9f6328d5dda..1da0acdebf53 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -12,8 +12,10 @@
  * for more details.
  */
 
+#include <linux/container_of.h>
 #include <linux/font.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/types.h>
 
@@ -26,11 +28,79 @@
  * Helpers for font_data_t
  */
 
+static struct font_data *to_font_data_struct(font_data_t *fd)
+{
+	return container_of(fd, struct font_data, data[0]);
+}
+
 static bool font_data_is_internal(font_data_t *fd)
 {
 	return is_kernel_rodata((unsigned long)fd);
 }
 
+static void font_data_free(font_data_t *fd)
+{
+	if (WARN_ON(font_data_is_internal(fd)))
+		return;
+
+	kfree(to_font_data_struct(fd));
+}
+
+/**
+ * font_data_get - Acquires a reference on font data
+ * @fd: Font data
+ *
+ * Font data from user space is reference counted. The helper
+ * font_data_get() increases the reference counter by one. Invoke
+ * font_data_put() to release the reference.
+ *
+ * Internal font data is located in read-only memory. In this case
+ * the helper returns success without modifying the counter field.
+ * It is still required to call font_data_put() on internal font data.
+ */
+void font_data_get(font_data_t *fd)
+{
+	if (font_data_is_internal(fd))
+		return; /* never ref static data */
+
+	if (WARN_ON(!REFCOUNT(fd)))
+		return; /* should never be 0 */
+	++REFCOUNT(fd);
+}
+EXPORT_SYMBOL_GPL(font_data_get);
+
+/**
+ * font_data_put - Release a reference on font data
+ * @fd: Font data
+ *
+ * Font data from user space is reference counted. The helper
+ * font_data_put() decreases the reference counter by one. If this was
+ * the final reference, it frees the allocated memory.
+ *
+ * Internal font data is located in read-only memory. In this case
+ * the helper returns success without modifying the counter field.
+ *
+ * Returns:
+ * True if this was the final reference, false otherwise.
+ */
+bool font_data_put(font_data_t *fd)
+{
+	unsigned int count;
+
+	if (font_data_is_internal(fd))
+		return true; /* never unref static data */
+
+	if (WARN_ON(!REFCOUNT(fd)))
+		return true; /* should never be 0 */
+
+	count = --REFCOUNT(fd);
+	if (!count)
+		font_data_free(fd);
+
+	return !count;
+}
+EXPORT_SYMBOL_GPL(font_data_put);
+
 /**
  * font_data_size - Return size of the font data in bytes
  * @fd: Font data
-- 
2.53.0

[PATCH v2 11/13] lib/fonts: Create font_data_t from struct console_font with font_data_import()

[Thomas Zimmermann]

Add font_data_import() and update consoles to use it.

The implementation of font_data_import() is based on code from fbcon,
which supports overflow checks and crc32 checksums. Fbcon uses the crc32
checksum.

Newport_con now implements the same overflow checks as fbcon. As before,
this console does not support checksums, which are optional. Newport_con
can now also handle input font data with a vertical pitch other than 32
bytes. (The vertical pitch is the offset between two glyphs in the font
data.)

As an internal change, remove the const qualifier from the data field
if struct font_data. This allows font_data_import() to write the data
without type casting. For all users of the font data via font_data_t,
the stored data is still read only.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/video/console/newport_con.c | 22 ++--------
 drivers/video/fbdev/core/fbcon.c    | 38 ++----------------
 include/linux/font.h                |  6 ++-
 lib/fonts/fonts.c                   | 62 +++++++++++++++++++++++++++++
 4 files changed, 75 insertions(+), 53 deletions(-)

diff --git a/drivers/video/console/newport_con.c b/drivers/video/console/newport_con.c
index 1bc3cb1ea116..ecbbe2e4e2a6 100644
--- a/drivers/video/console/newport_con.c
+++ b/drivers/video/console/newport_con.c
@@ -501,31 +501,17 @@ static int newport_set_font(int unit, const struct console_font *op,
 {
 	int w = op->width;
 	int h = op->height;
-	int size = h * op->charcount;
 	int i;
 	font_data_t *new_data;
-	unsigned char *data = op->data, *p;
 
 	/* ladis: when I grow up, there will be a day... and more sizes will
 	 * be supported ;-) */
-	if ((w != 8) || (h != 16) || (vpitch != 32)
-	    || (op->charcount != 256 && op->charcount != 512))
+	if (w != 8 || h != 16 || (op->charcount != 256 && op->charcount != 512))
 		return -EINVAL;
 
-	if (!(new_data = kmalloc(FONT_EXTRA_WORDS * sizeof(int) + size,
-	     GFP_USER))) return -ENOMEM;
-
-	new_data += FONT_EXTRA_WORDS * sizeof(int);
-	FNTSIZE(new_data) = size;
-	REFCOUNT(new_data) = 1;	/* usage counter */
-	FNTSUM(new_data) = 0;
-
-	p = (unsigned char *)font_data_buf(new_data);
-	for (i = 0; i < op->charcount; i++) {
-		memcpy(p, data, h);
-		data += 32;
-		p += h;
-	}
+	new_data = font_data_import(op, vpitch, NULL);
+	if (IS_ERR(new_data))
+		return PTR_ERR(new_data);
 
 	/* check if font is already used by other console */
 	for (i = 0; i < MAX_NR_CONSOLES; i++) {
diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 00255ac92e42..53677c09a0ec 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -2039,8 +2039,6 @@ static void updatescrollmode(struct fbcon_display *p,
 	updatescrollmode_accel(p, info, vc);
 }
 
-#define PITCH(w) (((w) + 7) >> 3)
-
 static int fbcon_resize(struct vc_data *vc, unsigned int width,
 			unsigned int height, bool from_user)
 {
@@ -2424,7 +2422,6 @@ static int fbcon_do_set_font(struct vc_data *vc, int w, int h, int charcount,
 	resize = (w != vc->vc_font.width) || (h != vc->vc_font.height);
 	p->fontdata = data;
 	vc->vc_font.data = font_data_buf(p->fontdata);
-
 	old_width = vc->vc_font.width;
 	old_height = vc->vc_font.height;
 	old_charcount = vc->vc_font.charcount;
@@ -2482,11 +2479,8 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 	unsigned charcount = font->charcount;
 	int w = font->width;
 	int h = font->height;
-	int size, alloc_size;
-	int i, csum, ret;
+	int i, ret;
 	font_data_t *new_data;
-	const u8 *data = font->data;
-	int pitch = PITCH(font->width);
 
 	/* Is there a reason why fbconsole couldn't handle any charcount >256?
 	 * If not this check should be changed to charcount < 256 */
@@ -2510,34 +2504,10 @@ static int fbcon_set_font(struct vc_data *vc, const struct console_font *font,
 	if (fbcon_invalid_charcount(info, charcount))
 		return -EINVAL;
 
-	/* Check for integer overflow in font size calculation */
-	if (check_mul_overflow(h, pitch, &size) ||
-	    check_mul_overflow(size, charcount, &size))
-		return -EINVAL;
-
-	/* Check for overflow in allocation size calculation */
-	if (check_add_overflow(FONT_EXTRA_WORDS * sizeof(int), size, &alloc_size))
-		return -EINVAL;
-
-	new_data = kmalloc(alloc_size, GFP_USER);
-
-	if (!new_data)
-		return -ENOMEM;
-
-	memset((u8 *)new_data, 0, FONT_EXTRA_WORDS * sizeof(int));
-
-	new_data += FONT_EXTRA_WORDS * sizeof(int);
-	FNTSIZE(new_data) = size;
-	REFCOUNT(new_data) = 1;	/* usage counter */
-	for (i=0; i< charcount; i++) {
-		memcpy((u8 *)new_data + i * h * pitch, data + i * vpitch * pitch, h * pitch);
-	}
-
-	/* Since linux has a nice crc32 function use it for counting font
-	 * checksums. */
-	csum = crc32(0, new_data, size);
+	new_data = font_data_import(font, vpitch, crc32);
+	if (IS_ERR(new_data))
+		return PTR_ERR(new_data);
 
-	FNTSUM(new_data) = csum;
 	/* Check if the same font is on some other console already */
 	for (i = first_fb_vc; i <= last_fb_vc; i++) {
 		if (fb_display[i].fontdata &&
diff --git a/include/linux/font.h b/include/linux/font.h
index a8610201afb7..d3b8ca240152 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -13,6 +13,8 @@
 
 #include <linux/types.h>
 
+struct console_font;
+
 /*
  * font_data_t and helpers
  */
@@ -54,6 +56,8 @@ static inline const unsigned char *font_data_buf(font_data_t *fd)
 	return (const unsigned char *)fd;
 }
 
+font_data_t *font_data_import(const struct console_font *font, unsigned int vpitch,
+			      u32 (*calc_csum)(u32, const void *, size_t));
 void font_data_get(font_data_t *fd);
 bool font_data_put(font_data_t *fd);
 unsigned int font_data_size(font_data_t *fd);
@@ -124,7 +128,7 @@ extern const struct font_desc *get_default_font(int xres, int yres,
 
 struct font_data {
 	unsigned int extra[FONT_EXTRA_WORDS];
-	const unsigned char data[];
+	unsigned char data[];
 } __packed;
 
 #endif /* _VIDEO_FONT_H */
diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index 1da0acdebf53..9b5355f6d2dc 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -14,7 +14,9 @@
 
 #include <linux/container_of.h>
 #include <linux/font.h>
+#include <linux/kd.h>
 #include <linux/module.h>
+#include <linux/overflow.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/types.h>
@@ -24,6 +26,8 @@
 #include <asm/setup.h>
 #endif
 
+#define console_font_pitch(font) DIV_ROUND_UP((font)->width, 8)
+
 /*
  * Helpers for font_data_t
  */
@@ -46,6 +50,64 @@ static void font_data_free(font_data_t *fd)
 	kfree(to_font_data_struct(fd));
 }
 
+/**
+ * font_data_import - Allocates and initializes font data from user space
+ * @font: A font from user space
+ * @vpitch: The size of a single glyph in @font in bytes
+ * @calc_csum: An optional helper to calculate a chechsum
+ *
+ * Font data from user space must be translated to the kernel's format. The
+ * font's glyph geometry and data is provided in @font. The parameter @vpitch
+ * gives the number of bytes per glyph, including trailing bytes.
+ *
+ * The parameter @calc_sum is optional. Fbcon passes crc32() to calculate the
+ * font data's checksum.
+ *
+ * Returns:
+ * Newly initialized font data on success, or a pointer-encoded errno value otherwise.
+ */
+font_data_t *font_data_import(const struct console_font *font, unsigned int vpitch,
+			      u32 (*calc_csum)(u32, const void *, size_t))
+{
+	unsigned int pitch = console_font_pitch(font);
+	unsigned int h = font->height;
+	unsigned int charcount = font->charcount;
+	const unsigned char *data = font->data;
+	u32 csum = 0;
+	struct font_data *font_data;
+	int size, alloc_size;
+	unsigned int i;
+	font_data_t *fd;
+
+	/* Check for integer overflow in font-size calculation */
+	if (check_mul_overflow(h, pitch, &size) ||
+	    check_mul_overflow(size, charcount, &size))
+		return ERR_PTR(-EINVAL);
+
+	/* Check for overflow in allocation size calculation */
+	if (check_add_overflow(sizeof(*font_data), size, &alloc_size))
+		return ERR_PTR(-EINVAL);
+
+	font_data = kmalloc(alloc_size, GFP_USER);
+	if (!font_data)
+		return ERR_PTR(-ENOMEM);
+	memset(font_data->extra, 0, sizeof(font_data->extra));
+
+	for (i = 0; i < charcount; ++i)
+		memcpy(font_data->data + i * h * pitch, data + i * vpitch * pitch, h * pitch);
+
+	if (calc_csum)
+		csum = calc_csum(0, font_data->data, size);
+
+	fd = font_data->data;
+	REFCOUNT(fd) = 1; /* start with reference acquired */
+	FNTSIZE(fd) = size;
+	FNTSUM(fd) = csum;
+
+	return fd;
+}
+EXPORT_SYMBOL_GPL(font_data_import);
+
 /**
  * font_data_get - Acquires a reference on font data
  * @fd: Font data
-- 
2.53.0

[PATCH v2 12/13] lib/fonts: Store font data for user space with font_data_export()

[Thomas Zimmermann]

Add font_data_export() and update consoles to use it.

The helper font_data_export() is based on code in fbcon_get_font().
It extends the size of a single glyph to match the requested vpitch,
which us usually 32 bytes for fonts from user space. Internal fonts
have a pitch according to the glyph's height.

The implementation of font_data_export() differs in several ways from
the original code. The original implementation distinguished between
different pitches of the font data. This is not necessary as the pitch
is a parameter in the copying.

There was also special handling for a font pitch of 3 bytes, which got
expanded to 4 bytes (with trailing bits on each scanline). The logic
originated from long before git history exists even in the historical
tree. So it is not clear why this was implemented. It is not what user
space expects. The setfont utitlity loads font with 3-bytes pitches and
expects to read such fonts with a 3-byte pitch. For any font width, the
font pitch is always the width extended to the next multiple of 8. See
[1] for the user-space font-reading code.

With the changes ot handling the font pitches, font_data_export() replaces
the original code's various special cases with a single copying logic.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://github.com/legionus/kbd/blob/v2.9.0/src/libkfont/kdfontop.c#L73 # [1]
---
 drivers/video/fbdev/core/fbcon.c | 57 ++------------------------------
 include/linux/font.h             |  1 +
 lib/fonts/fonts.c                | 40 ++++++++++++++++++++++
 3 files changed, 43 insertions(+), 55 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 53677c09a0ec..8641b0b3edc4 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -2282,68 +2282,15 @@ static bool fbcon_blank(struct vc_data *vc, enum vesa_blank_mode blank,
 
 static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigned int vpitch)
 {
-	struct fbcon_display *p = &fb_display[vc->vc_num];
-	font_data_t *fontdata = p->fontdata;
-	u8 *data = font->data;
-	int i, j;
+	const struct fbcon_display *p = &fb_display[vc->vc_num];
 
 	font->width = vc->vc_font.width;
 	font->height = vc->vc_font.height;
 	if (font->height > vpitch)
 		return -ENOSPC;
 	font->charcount = vc->vc_hi_font_mask ? 512 : 256;
-	if (!font->data)
-		return 0;
-
-	if (font->width <= 8) {
-		j = vc->vc_font.height;
-		if (font->charcount * j > font_data_size(fontdata))
-			return -EINVAL;
 
-		for (i = 0; i < font->charcount; i++) {
-			memcpy(data, fontdata, j);
-			memset(data + j, 0, vpitch - j);
-			data += vpitch;
-			fontdata += j;
-		}
-	} else if (font->width <= 16) {
-		j = vc->vc_font.height * 2;
-		if (font->charcount * j > font_data_size(fontdata))
-			return -EINVAL;
-
-		for (i = 0; i < font->charcount; i++) {
-			memcpy(data, fontdata, j);
-			memset(data + j, 0, 2*vpitch - j);
-			data += 2*vpitch;
-			fontdata += j;
-		}
-	} else if (font->width <= 24) {
-		if (font->charcount * (vc->vc_font.height * sizeof(u32)) > font_data_size(fontdata))
-			return -EINVAL;
-
-		for (i = 0; i < font->charcount; i++) {
-			for (j = 0; j < vc->vc_font.height; j++) {
-				*data++ = fontdata[0];
-				*data++ = fontdata[1];
-				*data++ = fontdata[2];
-				fontdata += sizeof(u32);
-			}
-			memset(data, 0, 3 * (vpitch - j));
-			data += 3 * (vpitch - j);
-		}
-	} else {
-		j = vc->vc_font.height * 4;
-		if (font->charcount * j > font_data_size(fontdata))
-			return -EINVAL;
-
-		for (i = 0; i < font->charcount; i++) {
-			memcpy(data, fontdata, j);
-			memset(data + j, 0, 4 * vpitch - j);
-			data += 4 * vpitch;
-			fontdata += j;
-		}
-	}
-	return 0;
+	return font_data_export(p->fontdata, font, vpitch);
 }
 
 /* set/clear vc_hi_font_mask and update vc attrs accordingly */
diff --git a/include/linux/font.h b/include/linux/font.h
index d3b8ca240152..e2e02e40c365 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -62,6 +62,7 @@ void font_data_get(font_data_t *fd);
 bool font_data_put(font_data_t *fd);
 unsigned int font_data_size(font_data_t *fd);
 bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs);
+int font_data_export(font_data_t *fd, struct console_font *font, unsigned int vpitch);
 
 /*
  * Font description
diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index 9b5355f6d2dc..1830e6ae9c87 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -202,6 +202,46 @@ bool font_data_is_equal(font_data_t *lhs, font_data_t *rhs)
 }
 EXPORT_SYMBOL_GPL(font_data_is_equal);
 
+/**
+ * font_data_export - Stores font data for user space
+ * @fd: Font data
+ * @font: A font for user space
+ * @vpitch: The size of a single glyph in @font in bytes
+ *
+ * Store the font data given in @fd to the font in @font. Values and
+ * pointers in @font are pre-initialized. This helper mostly checks some
+ * corner cases and translates glyph sizes according to the value given
+ * @vpitch.
+ *
+ * Returns:
+ * 0 on success, or a negative errno code otherwise.
+ */
+int font_data_export(font_data_t *fd, struct console_font *font, unsigned int vpitch)
+{
+	const unsigned char *font_data = font_data_buf(fd);
+	unsigned char *data = font->data;
+	unsigned int pitch = console_font_pitch(font);
+	unsigned int glyphsize, i;
+
+	if (!font->width || !font->height || !font->charcount || !font->data)
+		return 0;
+
+	glyphsize = font->height * pitch;
+
+	if (font->charcount * glyphsize > font_data_size(fd))
+		return -EINVAL;
+
+	for (i = 0; i < font->charcount; i++) {
+		memcpy(data, font_data, glyphsize);
+		memset(data + glyphsize, 0, pitch * vpitch - glyphsize);
+		data += pitch * vpitch;
+		font_data += glyphsize;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(font_data_export);
+
 /*
  * Font lookup
  */
-- 
2.53.0

[PATCH v2 13/13] lib/fonts: Remove internal symbols and macros from public header file

[Thomas Zimmermann]

Define access macros for font_data_t in fonts.c. Define struct font_data
and declare most of the font symbols in the internal header font.h, where
they can only be seen by the font code.

Also move font indices into internal font.h. They appear to be unused
though. There is m86k assembly code that operates on the idx field, so
leave them in place for now.

List all built-in fonts in a separate section in the public header file.

v2:
- do not add config guards around font symbols (Helge)
- keep declaration of built-in fonts in public header

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 include/linux/font.h       | 57 ++++++++++++--------------------------
 lib/fonts/font.h           | 38 +++++++++++++++++++++++++
 lib/fonts/font_10x18.c     |  2 +-
 lib/fonts/font_6x10.c      |  3 +-
 lib/fonts/font_6x11.c      |  2 +-
 lib/fonts/font_6x8.c       |  3 +-
 lib/fonts/font_7x14.c      |  2 +-
 lib/fonts/font_8x16.c      |  3 +-
 lib/fonts/font_8x8.c       |  2 +-
 lib/fonts/font_acorn_8x8.c |  2 +-
 lib/fonts/font_mini_4x6.c  |  2 +-
 lib/fonts/font_pearl_8x8.c |  2 +-
 lib/fonts/font_sun12x22.c  |  3 +-
 lib/fonts/font_sun8x16.c   |  3 +-
 lib/fonts/font_ter10x18.c  |  4 ++-
 lib/fonts/font_ter16x32.c  |  4 ++-
 lib/fonts/fonts.c          |  8 +++++-
 17 files changed, 85 insertions(+), 55 deletions(-)
 create mode 100644 lib/fonts/font.h

diff --git a/include/linux/font.h b/include/linux/font.h
index e2e02e40c365..63a8aee8e37d 100644
--- a/include/linux/font.h
+++ b/include/linux/font.h
@@ -77,36 +77,6 @@ struct font_desc {
     int pref;
 };
 
-#define VGA8x8_IDX	0
-#define VGA8x16_IDX	1
-#define PEARL8x8_IDX	2
-#define VGA6x11_IDX	3
-#define FONT7x14_IDX	4
-#define	FONT10x18_IDX	5
-#define SUN8x16_IDX	6
-#define SUN12x22_IDX	7
-#define ACORN8x8_IDX	8
-#define	MINI4x6_IDX	9
-#define FONT6x10_IDX	10
-#define TER16x32_IDX	11
-#define FONT6x8_IDX	12
-#define TER10x18_IDX	13
-
-extern const struct font_desc	font_vga_8x8,
-			font_vga_8x16,
-			font_pearl_8x8,
-			font_vga_6x11,
-			font_7x14,
-			font_10x18,
-			font_sun_8x16,
-			font_sun_12x22,
-			font_acorn_8x8,
-			font_mini_4x6,
-			font_6x10,
-			font_ter_16x32,
-			font_6x8,
-			font_ter_10x18;
-
 /* Find a font with a specific name */
 
 extern const struct font_desc *find_font(const char *name);
@@ -120,16 +90,23 @@ extern const struct font_desc *get_default_font(int xres, int yres,
 /* Max. length for the name of a predefined font */
 #define MAX_FONT_NAME	32
 
-/* Extra word getters */
-#define REFCOUNT(fd)	(((int *)(fd))[-1])
-#define FNTSIZE(fd)	(((int *)(fd))[-2])
-#define FNTSUM(fd)	(((int *)(fd))[-4])
-
-#define FONT_EXTRA_WORDS 4
+/*
+ * Built-in fonts
+ */
 
-struct font_data {
-	unsigned int extra[FONT_EXTRA_WORDS];
-	unsigned char data[];
-} __packed;
+extern const struct font_desc font_10x18;
+extern const struct font_desc font_6x10;
+extern const struct font_desc font_6x8;
+extern const struct font_desc font_7x14;
+extern const struct font_desc font_acorn_8x8;
+extern const struct font_desc font_mini_4x6;
+extern const struct font_desc font_pearl_8x8;
+extern const struct font_desc font_sun_12x22;
+extern const struct font_desc font_sun_8x16;
+extern const struct font_desc font_ter_10x18;
+extern const struct font_desc font_ter_16x32;
+extern const struct font_desc font_vga_6x11;
+extern const struct font_desc font_vga_8x16;
+extern const struct font_desc font_vga_8x8;
 
 #endif /* _VIDEO_FONT_H */
diff --git a/lib/fonts/font.h b/lib/fonts/font.h
new file mode 100644
index 000000000000..4f1adf0b6b54
--- /dev/null
+++ b/lib/fonts/font.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LIB_FONTS_FONT_H
+#define _LIB_FONTS_FONT_H
+
+#include <linux/font.h>
+
+/*
+ * Font data
+ */
+
+#define FONT_EXTRA_WORDS 4
+
+struct font_data {
+	unsigned int extra[FONT_EXTRA_WORDS];
+	unsigned char data[];
+} __packed;
+
+/*
+ * Built-in fonts
+ */
+
+#define VGA8x8_IDX	0
+#define VGA8x16_IDX	1
+#define PEARL8x8_IDX	2
+#define VGA6x11_IDX	3
+#define FONT7x14_IDX	4
+#define	FONT10x18_IDX	5
+#define SUN8x16_IDX	6
+#define SUN12x22_IDX	7
+#define ACORN8x8_IDX	8
+#define	MINI4x6_IDX	9
+#define FONT6x10_IDX	10
+#define TER16x32_IDX	11
+#define FONT6x8_IDX	12
+#define TER10x18_IDX	13
+
+#endif
diff --git a/lib/fonts/font_10x18.c b/lib/fonts/font_10x18.c
index 5d940db626e7..10edebc4bb74 100644
--- a/lib/fonts/font_10x18.c
+++ b/lib/fonts/font_10x18.c
@@ -4,7 +4,7 @@
  * by Jurriaan Kalkman 06-2005  *
  ********************************/
 
-#include <linux/font.h>
+#include "font.h"
 
 #define FONTDATAMAX 9216
 
diff --git a/lib/fonts/font_6x10.c b/lib/fonts/font_6x10.c
index e65df019e0d2..660d3a371b30 100644
--- a/lib/fonts/font_6x10.c
+++ b/lib/fonts/font_6x10.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/font.h>
+
+#include "font.h"
 
 #define FONTDATAMAX 2560
 
diff --git a/lib/fonts/font_6x11.c b/lib/fonts/font_6x11.c
index bd76b3f6b635..671487ccc172 100644
--- a/lib/fonts/font_6x11.c
+++ b/lib/fonts/font_6x11.c
@@ -5,7 +5,7 @@
 /*                                            */
 /**********************************************/
 
-#include <linux/font.h>
+#include "font.h"
 
 #define FONTDATAMAX (11*256)
 
diff --git a/lib/fonts/font_6x8.c b/lib/fonts/font_6x8.c
index 06ace7792521..5811ee07f4d8 100644
--- a/lib/fonts/font_6x8.c
+++ b/lib/fonts/font_6x8.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/font.h>
+
+#include "font.h"
 
 #define FONTDATAMAX 2048
 
diff --git a/lib/fonts/font_7x14.c b/lib/fonts/font_7x14.c
index a2f561c9fa04..0c7475d643c8 100644
--- a/lib/fonts/font_7x14.c
+++ b/lib/fonts/font_7x14.c
@@ -4,7 +4,7 @@
 /* by Jurriaan Kalkman 05-2005        */
 /**************************************/
 
-#include <linux/font.h>
+#include "font.h"
 
 #define FONTDATAMAX 3584
 
diff --git a/lib/fonts/font_8x16.c b/lib/fonts/font_8x16.c
index 06ae14088514..523e95c75569 100644
--- a/lib/fonts/font_8x16.c
+++ b/lib/fonts/font_8x16.c
@@ -5,9 +5,10 @@
 /*                                            */
 /**********************************************/
 
-#include <linux/font.h>
 #include <linux/module.h>
 
+#include "font.h"
+
 #define FONTDATAMAX 4096
 
 static const struct font_data fontdata_8x16 = {
diff --git a/lib/fonts/font_8x8.c b/lib/fonts/font_8x8.c
index 69570b8c31af..e5b697fc9675 100644
--- a/lib/fonts/font_8x8.c
+++ b/lib/fonts/font_8x8.c
@@ -5,7 +5,7 @@
 /*                                            */
 /**********************************************/
 
-#include <linux/font.h>
+#include "font.h"
 
 #define FONTDATAMAX 2048
 
diff --git a/lib/fonts/font_acorn_8x8.c b/lib/fonts/font_acorn_8x8.c
index af5fa72aa8b7..36c51016769d 100644
--- a/lib/fonts/font_acorn_8x8.c
+++ b/lib/fonts/font_acorn_8x8.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Acorn-like font definition, with PC graphics characters */
 
-#include <linux/font.h>
+#include "font.h"
 
 #define FONTDATAMAX 2048
 
diff --git a/lib/fonts/font_mini_4x6.c b/lib/fonts/font_mini_4x6.c
index cc21dc70cfd1..dc919c160dde 100644
--- a/lib/fonts/font_mini_4x6.c
+++ b/lib/fonts/font_mini_4x6.c
@@ -39,7 +39,7 @@ __END__;
    MSBit to LSBit = left to right.
  */
 
-#include <linux/font.h>
+#include "font.h"
 
 #define FONTDATAMAX 1536
 
diff --git a/lib/fonts/font_pearl_8x8.c b/lib/fonts/font_pearl_8x8.c
index ae98ca17982e..2438b374acea 100644
--- a/lib/fonts/font_pearl_8x8.c
+++ b/lib/fonts/font_pearl_8x8.c
@@ -10,7 +10,7 @@
 /*                                            */
 /**********************************************/
 
-#include <linux/font.h>
+#include "font.h"
 
 #define FONTDATAMAX 2048
 
diff --git a/lib/fonts/font_sun12x22.c b/lib/fonts/font_sun12x22.c
index 91daf5ab8b6b..2afbc144bea8 100644
--- a/lib/fonts/font_sun12x22.c
+++ b/lib/fonts/font_sun12x22.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/font.h>
+
+#include "font.h"
 
 #define FONTDATAMAX 11264
 
diff --git a/lib/fonts/font_sun8x16.c b/lib/fonts/font_sun8x16.c
index 81bb4eeae04e..2b7b2d8e548a 100644
--- a/lib/fonts/font_sun8x16.c
+++ b/lib/fonts/font_sun8x16.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/font.h>
+
+#include "font.h"
 
 #define FONTDATAMAX 4096
 
diff --git a/lib/fonts/font_ter10x18.c b/lib/fonts/font_ter10x18.c
index 80356e9d56c7..3f30b4a211ab 100644
--- a/lib/fonts/font_ter10x18.c
+++ b/lib/fonts/font_ter10x18.c
@@ -1,7 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/font.h>
+
 #include <linux/module.h>
 
+#include "font.h"
+
 #define FONTDATAMAX 9216
 
 static const struct font_data fontdata_ter10x18 = {
diff --git a/lib/fonts/font_ter16x32.c b/lib/fonts/font_ter16x32.c
index 5baedc573dd6..93616cffe642 100644
--- a/lib/fonts/font_ter16x32.c
+++ b/lib/fonts/font_ter16x32.c
@@ -1,7 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0
-#include <linux/font.h>
+
 #include <linux/module.h>
 
+#include "font.h"
+
 #define FONTDATAMAX 16384
 
 static const struct font_data fontdata_ter16x32 = {
diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index 1830e6ae9c87..198aae869be2 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -13,7 +13,6 @@
  */
 
 #include <linux/container_of.h>
-#include <linux/font.h>
 #include <linux/kd.h>
 #include <linux/module.h>
 #include <linux/overflow.h>
@@ -26,12 +25,19 @@
 #include <asm/setup.h>
 #endif
 
+#include "font.h"
+
 #define console_font_pitch(font) DIV_ROUND_UP((font)->width, 8)
 
 /*
  * Helpers for font_data_t
  */
 
+/* Extra word getters */
+#define REFCOUNT(fd)	(((int *)(fd))[-1])
+#define FNTSIZE(fd)	(((int *)(fd))[-2])
+#define FNTSUM(fd)	(((int *)(fd))[-4])
+
 static struct font_data *to_font_data_struct(font_data_t *fd)
 {
 	return container_of(fd, struct font_data, data[0]);
-- 
2.53.0

Re: [PATCH v2 00/13] vc,fbcon,fonts: Proper handling of font data

[Helge Deller]

On 3/2/26 15:08, Thomas Zimmermann wrote:
> Provide helpers for handling console font data. Update consoles and VT.
> 
> VT's vc_state stores font data as a plain byte array of glphys. Fbcon,
> newport_con and the kernel's internal fonts store the glyph data as an
> array of plain bytes plus a hidden header for reference counting, check
> sums and buffer sizes. The reference counting only works for user-space
> fonts but not for internal fonts. Font-data handling is duplicated in
> several places. Most of the font handling is open-coded and mixed up with
> VT's plain glyph arrays.
> 
> To address these issues, add proper handling of font data to all involved
> components: struct vc_font for font state in VC; a font data type for the
> consoles. Then implement interfaces for handling font data one by one.
> 
> Patch 1 prepares the fbdev interface.
> 
> Patches 2 to 4 prepare VT's font handling.
> 
> Patches 5 to 13 refactor fbcon and newport_con to use clean interfaces for
> their fonts.
> 
> Fbcon has long been a source of problems and bug reports. [1] With its
> confusing implementation, it is hard to find the cause of these bugs.
> Cleaning up the fbcon code will hopefully help with resolving bug reports
> in the future.
> 
> The series has been tested with fbcon under DRM's bochs driver by changing
> fonts at runtime using the setfont utility. [2] The changes to newport_con
> have only been tested to compile.
> 
> v2:
> - keep declaring the internal fonts in the public header file (Helge)
> - rebase and clean up
> 
> [1] https://lore.kernel.org/all/6992c84c.a70a0220.2c38d7.00e8.GAE@google.com/
> [2] https://www.man7.org/linux/man-pages/man8/setfont.8.html
> 
> Thomas Zimmermann (13):
>    fbdev: Declare src parameter of fb_pad_ helpers as constant
>    vt: Remove trailing whitespaces
>    vt: Store font in struct vc_font
>    vt: Calculate font-buffer size with vc_font_size()
>    lib/fonts: Remove trailing whitespaces
>    lib/fonts: Remove FNTCHARCNT()
>    lib/fonts: Store font data as font_data_t; update consoles
>    lib/fonts: Read font size with font_data_size()
>    lib/fonts: Compare font data for equality with font_data_is_equal()
>    lib/fonts: Manage font-data lifetime with font_data_get/_put()
>    lib/fonts: Create font_data_t from struct console_font with
>      font_data_import()
>    lib/fonts: Store font data for user space with font_data_export()
>    lib/fonts: Remove internal symbols and macros from public header file
> 
>   drivers/video/console/newport_con.c |  61 +++----
>   drivers/video/fbdev/core/bitblit.c  |  11 +-
>   drivers/video/fbdev/core/fbcon.c    | 194 +++++++----------------
>   drivers/video/fbdev/core/fbcon.h    |   8 +-
>   drivers/video/fbdev/core/fbmem.c    |   6 +-
>   include/linux/console_struct.h      |  59 ++++++-
>   include/linux/fb.h                  |  10 +-
>   include/linux/font.h                | 115 +++++++++-----
>   lib/fonts/font.h                    |  38 +++++
>   lib/fonts/font_10x18.c              |   2 +-
>   lib/fonts/font_6x10.c               |   3 +-
>   lib/fonts/font_6x11.c               |   2 +-
>   lib/fonts/font_6x8.c                |   3 +-
>   lib/fonts/font_7x14.c               |   2 +-
>   lib/fonts/font_8x16.c               |   3 +-
>   lib/fonts/font_8x8.c                |   2 +-
>   lib/fonts/font_acorn_8x8.c          |   4 +-
>   lib/fonts/font_mini_4x6.c           |  10 +-
>   lib/fonts/font_pearl_8x8.c          |   2 +-
>   lib/fonts/font_sun12x22.c           |   3 +-
>   lib/fonts/font_sun8x16.c            |   3 +-
>   lib/fonts/font_ter10x18.c           |   4 +-
>   lib/fonts/font_ter16x32.c           |   4 +-
>   lib/fonts/fonts.c                   | 236 +++++++++++++++++++++++++++-
>   24 files changed, 518 insertions(+), 267 deletions(-)
>   create mode 100644 lib/fonts/font.h
Thomas, thanks for the nice cleanup!
Beside a few minor comments which I posted to the various patches, the series looks good.

I've applied it for further testing to the fbdev git tree.
In case you send later v3 series, I'll update it.

Thanks a lot!
Helge

Re: [PATCH v2 00/13] vc,fbcon,fonts: Proper handling of font data

[Thomas Zimmermann]

Hi

Am 03.03.26 um 16:29 schrieb Helge Deller:
> On 3/2/26 15:08, Thomas Zimmermann wrote:
>> Provide helpers for handling console font data. Update consoles and VT.
>>
>> VT's vc_state stores font data as a plain byte array of glphys. Fbcon,
>> newport_con and the kernel's internal fonts store the glyph data as an
>> array of plain bytes plus a hidden header for reference counting, check
>> sums and buffer sizes. The reference counting only works for user-space
>> fonts but not for internal fonts. Font-data handling is duplicated in
>> several places. Most of the font handling is open-coded and mixed up 
>> with
>> VT's plain glyph arrays.
>>
>> To address these issues, add proper handling of font data to all 
>> involved
>> components: struct vc_font for font state in VC; a font data type for 
>> the
>> consoles. Then implement interfaces for handling font data one by one.
>>
>> Patch 1 prepares the fbdev interface.
>>
>> Patches 2 to 4 prepare VT's font handling.
>>
>> Patches 5 to 13 refactor fbcon and newport_con to use clean 
>> interfaces for
>> their fonts.
>>
>> Fbcon has long been a source of problems and bug reports. [1] With its
>> confusing implementation, it is hard to find the cause of these bugs.
>> Cleaning up the fbcon code will hopefully help with resolving bug 
>> reports
>> in the future.
>>
>> The series has been tested with fbcon under DRM's bochs driver by 
>> changing
>> fonts at runtime using the setfont utility. [2] The changes to 
>> newport_con
>> have only been tested to compile.
>>
>> v2:
>> - keep declaring the internal fonts in the public header file (Helge)
>> - rebase and clean up
>>
>> [1] 
>> https://lore.kernel.org/all/6992c84c.a70a0220.2c38d7.00e8.GAE@google.com/
>> [2] https://www.man7.org/linux/man-pages/man8/setfont.8.html
>>
>> Thomas Zimmermann (13):
>>    fbdev: Declare src parameter of fb_pad_ helpers as constant
>>    vt: Remove trailing whitespaces
>>    vt: Store font in struct vc_font
>>    vt: Calculate font-buffer size with vc_font_size()
>>    lib/fonts: Remove trailing whitespaces
>>    lib/fonts: Remove FNTCHARCNT()
>>    lib/fonts: Store font data as font_data_t; update consoles
>>    lib/fonts: Read font size with font_data_size()
>>    lib/fonts: Compare font data for equality with font_data_is_equal()
>>    lib/fonts: Manage font-data lifetime with font_data_get/_put()
>>    lib/fonts: Create font_data_t from struct console_font with
>>      font_data_import()
>>    lib/fonts: Store font data for user space with font_data_export()
>>    lib/fonts: Remove internal symbols and macros from public header file
>>
>>   drivers/video/console/newport_con.c |  61 +++----
>>   drivers/video/fbdev/core/bitblit.c  |  11 +-
>>   drivers/video/fbdev/core/fbcon.c    | 194 +++++++----------------
>>   drivers/video/fbdev/core/fbcon.h    |   8 +-
>>   drivers/video/fbdev/core/fbmem.c    |   6 +-
>>   include/linux/console_struct.h      |  59 ++++++-
>>   include/linux/fb.h                  |  10 +-
>>   include/linux/font.h                | 115 +++++++++-----
>>   lib/fonts/font.h                    |  38 +++++
>>   lib/fonts/font_10x18.c              |   2 +-
>>   lib/fonts/font_6x10.c               |   3 +-
>>   lib/fonts/font_6x11.c               |   2 +-
>>   lib/fonts/font_6x8.c                |   3 +-
>>   lib/fonts/font_7x14.c               |   2 +-
>>   lib/fonts/font_8x16.c               |   3 +-
>>   lib/fonts/font_8x8.c                |   2 +-
>>   lib/fonts/font_acorn_8x8.c          |   4 +-
>>   lib/fonts/font_mini_4x6.c           |  10 +-
>>   lib/fonts/font_pearl_8x8.c          |   2 +-
>>   lib/fonts/font_sun12x22.c           |   3 +-
>>   lib/fonts/font_sun8x16.c            |   3 +-
>>   lib/fonts/font_ter10x18.c           |   4 +-
>>   lib/fonts/font_ter16x32.c           |   4 +-
>>   lib/fonts/fonts.c                   | 236 +++++++++++++++++++++++++++-
>>   24 files changed, 518 insertions(+), 267 deletions(-)
>>   create mode 100644 lib/fonts/font.h
> Thomas, thanks for the nice cleanup!
> Beside a few minor comments which I posted to the various patches, the 
> series looks good.
>
> I've applied it for further testing to the fbdev git tree.

Great, thanks!

> In case you send later v3 series, I'll update it.

I'd preferably not modify the data structures for now. Shall I send an 
update for the typos?

Best regards
Thomas

>
> Thanks a lot!
> Helge

-- 
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)