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
>
