44 Commits
Author SHA1 Message Date
Thomas ZimmermannandHelge Deller d237f719b2 lib/fonts: Fix bit position when rotating by 180 degrees
Fix the horizontal bit position when rotating a glyph by 180°. The
original code in rotate_ud() rounded the value in width up to a
multiple of 8, aka the bit pitch, and calculated the rotated pixel
from that value. The new code stores the glyph's pitch in bit_pitch,
but fails to update the rotated pixel's output accordingly. Simply
replacing the variable does this.

The bug can be reproduced by setting a font with an unaligned width,
such as sun12x22, like this:

 setfont sun12x22
 echo 2 > /sys/class/graphics/fbcon/rotate

Without the fix, the font looks distorted.

Fixes: a30e9e6b01 ("lib/fonts: Refactor glyph-rotation helpers")
Closes: https://lore.gitlab.freedesktop.org/drm-ai-reviews/review-patch7-20260407092555.58816-8-tzimmermann@suse.de/
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-28 14:18:51 +02:00
Thomas ZimmermannandHelge Deller cfa72955a0 lib/fonts: Implement font rotation
Move the core of fbcon's font-rotation code to the font library as
the new helper font_data_rotate(). The code can rotate in steps of
90°. For completeness, it also copies the glyph data for multiples
of 360°.

Bring back the memset optimization. A memset to 0 again clears the
whole glyph output buffer. Then use the internal rotation helpers on
the cleared output. Fbcon's original implementation worked like this,
but lost it during refactoring.

Replace fbcon's font-rotation code with the new implementations.
All that's left to do for fbcon is to maintain its internal fbcon
state.

v2:
- fix typos

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-07 17:38:07 +02:00
Thomas ZimmermannandHelge Deller a30e9e6b01 lib/fonts: Refactor glyph-rotation helpers
Change the signatures of the glyph-rotation helpers to match their
public interfaces. Drop the inline qualifier.

Rename several variables to better match their meaning. Especially
rename variables to bit_pitch (or a variant thereof) if they store
a pitch value in bits per scanline. The original code is fairly
confusing about this. Move the calculation of the bit pitch into the
new helper font_glyph_bit_pitch().

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-07 17:38:07 +02:00
Thomas ZimmermannandHelge Deller 6ad4ed8408 lib/fonts: Refactor glyph-pattern helpers
Change the signatures of the pattern helpers to align them with other
font-glyph helpers: use the font_glyph_ prefix and pass the glyph
buffer first.

Calculating the position of the involved bit is somewhat obfuscated
in the original implementation. Move it into the new helper
__font_glyph_pos() and use the result as array index and bit position.

Note that these bit helpers use a bit pitch, while other code uses a
byte pitch. This is intentional and required here.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-07 17:38:07 +02:00
Thomas ZimmermannandHelge Deller bdfd943231 lib/fonts: Implement glyph rotation
Move the glyph rotation helpers from fbcon to the font library. Wrap them
behind clean interfaces. Also clear the output memory to zero. Previously,
the implementation relied on the caller to do that.

Go through the fbcon code and callers of the glyph-rotation helpers. In
addition to the font rotation, there's also the cursor code, which uses
the rotation helpers.

The font-rotation relied on a single memset to zero for the whole font.
This is now multiple memsets on each glyph. This will be sorted out when
the font library also implements font rotation.

Building glyph rotation in the font library still depends on
CONFIG_FRAMEBUFFER_CONSOLE_ROTATION=y. If we get more users of the code,
we can still add a dedicated Kconfig symbol to the font library.

No changes have been made to the actual implementation of the rotate_*()
and pattern_*() functions. These will be refactored as separate changes.

v2:
- fix typos

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-07 17:38:07 +02:00
Thomas ZimmermannandHelge Deller de0b375bce lib/fonts: Clean up Makefile
Simplify the Makefile. Drop font-obj-y and sort the fonts by dictionary
order. Done in preparation for supporting optional font rotation.

v2:
- sort Makefile font entries by Family/Size in ascending order (Geert, Jiri)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-07 17:38:07 +02:00
Thomas ZimmermannandHelge Deller 97df896024 lib/fonts: Provide helpers for calculating glyph pitch and size
Implement pitch and size calculation for a single font glyph in the
new helpers font_glyph_pitch() and font_glyph_size(). Replace the
instances where the calculations are open-coded.

Note that in the case of fbcon console rotation, the parameters for
a glyph's width and height might be reversed. This is intentional.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-04-07 17:38:07 +02:00
Thomas ZimmermannandHelge Deller db65872b38 lib/fonts: Remove internal symbols and macros from public header file
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>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-03-09 15:47:21 +01:00
Thomas ZimmermannandHelge Deller c37bd7c8d3 lib/fonts: Store font data for user space with font_data_export()
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 to handling the font pitches, font_data_export() replaces
the original code's various special cases with a single copying logic.

v3:
- fix typos (Helge)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://github.com/legionus/kbd/blob/v2.9.0/src/libkfont/kdfontop.c#L73 # [1]
Signed-off-by: Helge Deller <deller@gmx.de>
2026-03-09 15:47:21 +01:00
Thomas ZimmermannandHelge Deller 514d0de7cf lib/fonts: Create font_data_t from struct console_font with font_data_import()
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.

v3:
- fix typos

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-03-09 15:47:21 +01:00
Thomas ZimmermannandHelge Deller 1e3c49aa03 lib/fonts: Compare font data for equality with font_data_is_equal()
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().

v3:
- rebase onto font_data_{get,put}()

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-03-09 15:47:21 +01:00
Thomas ZimmermannandHelge Deller 1de371b1f1 lib/fonts: Manage font-data lifetime with font_data_get/_put()
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 a refcount of zero for internal font data. 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 handling also covers this case.

v3:
- fix module linker error wrt font symbols (Nathan, Arnd)
- fix typos

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-03-09 15:47:21 +01:00
Thomas ZimmermannandHelge Deller e2e000a0b2 lib/fonts: Read font size with font_data_size()
Add font_data_size() and update consoles to use it.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-03-09 15:47:20 +01:00
Thomas ZimmermannandHelge Deller e7564d8063 lib/fonts: Remove trailing whitespaces
Fix coding style. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
2026-03-09 15:47:20 +01:00
Neilay KharwadkarandHelge Deller b08ee4d666 lib/fonts: Add Terminus 10x18 console font
Add a compile-in option for Terminus 10x18 bitmap console font
to improve readability on modern laptop displays.

On modern 13-16 inch laptop displays with high pixel density,
common scaled resolutions like 1280x800 and 1440x900 are widely
used.

At these resolutions, VGA 8x16 is too small and difficult to
read for extended periods, while Terminus 16x32 is too large,
providing only 25-28 rows. The existing 10x18 font has poor
readability.

Terminus 10x18 provides improved readability with its clean,
fixed-width design while maintaining practical row counts
(44-50 rows).

A comfortable and readable built-in font for early boot messages,
kernel panics or whenever userspace is unavailable.

The font was converted from standard Terminus ter-i18b.psf using
psftools and formatted to match kernel font conventions.

This patch is non-intrusive, no options are enabled by default
so most users won't notice a thing.

Signed-off-by: Neilay Kharwadkar <neilaykharwadkar@gmail.com>
Signed-off-by: Helge Deller <deller@gmx.de>
2025-12-02 19:57:01 +01:00
Arnd BergmannandJocelyn Falempe 322a00efec drm/log: select CONFIG_FONT_SUPPORT
Without fonts, this fails to link:

drivers/gpu/drm/clients/drm_log.o: in function `drm_log_init_client':
drm_log.c:(.text+0x3d4): undefined reference to `get_default_font'

Select this, like the other users do.

Fixes: f7b42442c4 ("drm/log: Introduce a new boot logger to draw the kmsg on the screen")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241212154003.1313437-1-arnd@kernel.org
2024-12-12 18:26:32 +01:00
Geert UytterhoevenandJocelyn Falempe a03a84bee3 lib/fonts: Fix visiblity of SUN12x22 and TER16x32 if DRM_PANIC
When CONFIG_FONTS ("Select compiled-in fonts") is not enabled, the user
should not be asked about any fonts.  However, when CONFIG_DRM_PANIC is
enabled, the user is still asked about the Sparc console 12x22 and
Terminus 16x32 fonts.

Fix this by moving the "|| DRM_PANIC" to where it belongs.
Split the dependency in two rules to improve readability.

Fixes: b94605a388 ("lib/fonts: Allow to select fonts for drm_panic")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ac474c6755800e61e18bd5af407c6acb449c5149.1718305355.git.geert+renesas@glider.be
2024-06-24 13:18:02 +02:00
Jocelyn Falempe b94605a388 lib/fonts: Allow to select fonts for drm_panic
drm_panic has been introduced recently, and uses the same fonts as
FRAMEBUFFER_CONSOLE.

Signed-off-by: Jocelyn Falempe <jfalempe@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20240419132243.154466-1-jfalempe@redhat.com
2024-05-02 09:40:17 +02:00
Linus Torvalds 4f55aa85a8 Merge tag 'fbdev-for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev
Pull fbdev updates from Helge Deller:

 - Allow console fonts up to 64x128 pixels (Samuel Thibault)

 - Prevent division-by-zero in fb monitor code (Roman Smirnov)

 - Drop Renesas ARM platforms from Mobile LCDC framebuffer driver (Geert
   Uytterhoeven)

 - Various code cleanups in viafb, uveafb and mb862xxfb drivers by
   Aleksandr Burakov, Li Zhijian and Michael Ellerman

* tag 'fbdev-for-6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
  fbdev: panel-tpo-td043mtea1: Convert sprintf() to sysfs_emit()
  fbmon: prevent division by zero in fb_videomode_from_videomode()
  fbcon: Increase maximum font width x height to 64 x 128
  fbdev: viafb: fix typo in hw_bitblt_1 and hw_bitblt_2
  fbdev: mb862xxfb: Fix defined but not used error
  fbdev: uvesafb: Convert sprintf/snprintf to sysfs_emit
  fbdev: Restrict FB_SH_MOBILE_LCDC to SuperH
2024-03-22 10:09:08 -07:00
Samuel ThibaultandHelge Deller 152609795d fbcon: Increase maximum font width x height to 64 x 128
By using bitmaps we actually support whatever size we would want, but
the console currently limits fonts to 64x128 (which gives 60x16 text on
4k screens), so we don't need more for now, and we can easily increase
later.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Signed-off-by: Helge Deller <deller@gmx.de>
2024-03-16 08:29:48 +01:00
Andreas Larsson 84b76d0582 lib/fonts: Allow Sparc console 8x16 font for sparc64 early boot text console
Allow FONT_SUN8x16 when EARLYFB is enabled for sparc64, even when
FRAMEBUFFER_CONSOLE is not to avoid the following warning for this case

   WARNING: unmet direct dependencies detected for FONT_SUN8x16
     Depends on [n]: FONT_SUPPORT [=y] && (FRAMEBUFFER_CONSOLE [=n] && (FONTS [=n] || SPARC [=y]) || BOOTX_TEXT)
     Selected by [y]:
     - EARLYFB [=y] && SPARC64 [=y]

by allowing it in the same manner as is done for powerpc in commit
0ebc7feae7 ("powerpc: Use shared font data").

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Fixes: 0f1991949d ("sparc: Use shared font data")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402241539.epQT43nI-lkp@intel.com/
Cc: "Dr. David Alan Gilbert" <linux@treblig.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Reviewed-by: Dr. David Alan Gilbert <linux@treblig.org>
Link: https://lore.kernel.org/r/20240307180742.900068-1-andreas@gaisler.com
2024-03-08 21:29:16 +01:00
Dr. David Alan GilbertandMichael Ellerman 0ebc7feae7 powerpc: Use shared font data
PowerPC has a 'btext' font used for the console which is almost identical
to the shared font_sun8x16, so use it rather than duplicating the data.

They were actually identical until about a decade ago when
   commit bcfbeecea1 ("drivers: console: font_: Change a glyph from
                        "broken bar" to "vertical line"")

which changed the | in the shared font to be a solid
bar rather than a broken bar.  That's the only difference.

This was originally spotted by the PMF source code analyser, which
noticed that sparc does the same thing with the same data, and they
also share a bunch of functions to manipulate the data.  I've previously
posted a near identical patch for sparc.

Tested very lightly with a boot without FS in qemu.

Signed-off-by: "Dr. David Alan Gilbert" <linux@treblig.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230825142754.1487900-1-linux@treblig.org
2023-10-01 23:09:02 +11:00
Gaosheng CuiandAndrew Morton 6fe888c4d2 lib/fonts: fix undefined behavior in bit shift for get_default_font
Shifting signed 32-bit value by 31 bits is undefined, so changing
significant bit to unsigned.  The UBSAN warning calltrace like below:

UBSAN: shift-out-of-bounds in lib/fonts/fonts.c:139:20
left shift of 1 by 31 places cannot be represented in type 'int'
 <TASK>
 dump_stack_lvl+0x7d/0xa5
 dump_stack+0x15/0x1b
 ubsan_epilogue+0xe/0x4e
 __ubsan_handle_shift_out_of_bounds+0x1e7/0x20c
 get_default_font+0x1c7/0x1f0
 fbcon_startup+0x347/0x3a0
 do_take_over_console+0xce/0x270
 do_fbcon_takeover+0xa1/0x170
 do_fb_registered+0x2a8/0x340
 fbcon_fb_registered+0x47/0xe0
 register_framebuffer+0x294/0x4a0
 __drm_fb_helper_initial_config_and_unlock+0x43c/0x880 [drm_kms_helper]
 drm_fb_helper_initial_config+0x52/0x80 [drm_kms_helper]
 drm_fbdev_client_hotplug+0x156/0x1b0 [drm_kms_helper]
 drm_fbdev_generic_setup+0xfc/0x290 [drm_kms_helper]
 bochs_pci_probe+0x6ca/0x772 [bochs]
 local_pci_probe+0x4d/0xb0
 pci_device_probe+0x119/0x320
 really_probe+0x181/0x550
 __driver_probe_device+0xc6/0x220
 driver_probe_device+0x32/0x100
 __driver_attach+0x195/0x200
 bus_for_each_dev+0xbb/0x120
 driver_attach+0x27/0x30
 bus_add_driver+0x22e/0x2f0
 driver_register+0xa9/0x190
 __pci_register_driver+0x90/0xa0
 bochs_pci_driver_init+0x52/0x1000 [bochs]
 do_one_initcall+0x76/0x430
 do_init_module+0x61/0x28a
 load_module+0x1f82/0x2e50
 __do_sys_finit_module+0xf8/0x190
 __x64_sys_finit_module+0x23/0x30
 do_syscall_64+0x58/0x80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
 </TASK>

Link: https://lkml.kernel.org/r/20221031113829.4183153-1-cuigaosheng1@huawei.com
Fixes: c81f717cb9 ("fbcon: Fix typo and bogus logic in get_default_font")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-11-18 13:55:09 -08:00
Zhen LeiandLinus Torvalds 9dbbc3b9d0 lib: fix spelling mistakes
Fix some spelling mistakes in comments:
permanentely ==> permanently
wont ==> won't
remaning ==> remaining
succed ==> succeed
shouldnt ==> shouldn't
alpha-numeric ==> alphanumeric
storeing ==> storing
funtion ==> function
documenation ==> documentation
Determin ==> Determine
intepreted ==> interpreted
ammount ==> amount
obious ==> obvious
interupts ==> interrupts
occured ==> occurred
asssociated ==> associated
taking into acount ==> taking into account
squence ==> sequence
stil ==> still
contiguos ==> contiguous
matchs ==> matches

Link: https://lkml.kernel.org/r/20210607072555.12416-1-thunder.leizhen@huawei.com
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-08 11:48:20 -07:00
Amanoel DawodandGreg Kroah-Hartman 384b77fd48 Fonts: font_ter16x32: Update font with new upstream Terminus release
This is just a maintenance patch to update font_ter16x32.c with changes
and minor fixes added in new upstream Terminus v4.49.

>From release notes of new version 4.49, this brings:
- Altered ascii grave in some sizes to be more useful as a back quote.
- Fixed 21B5, added 21B2 and 21B3.

Just as my initial submission of the font, above changes were obtained from
new ter-i32b.psf font source.

Terminus font sources are available for download at SourceForge:
https://sourceforge.net/projects/terminus-font/files/terminus-font-4.49/

Simply running `make` in source directory will build the .psf font files.

Signed-off-by: Amanoel Dawod <kernel@amanoeldawod.com>
Link: https://lore.kernel.org/r/20201226235840.26290-1-kernel@amanoeldawod.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07 21:06:25 +01:00