On Sun, Jun 7, 2026 at 2:02 PM Helge Deller [off-list ref] wrote:

The text display code used in the Risc PC kernel image decompression
code uses arch/arm/boot/compressed/font.c, which includes
lib/fonts/font_acorn_8x8.c, which further includes <linux/font.h>.

Since commit 97df8960240a ("lib/fonts: Provide helpers for calculating
glyph pitch and size") <linux/font.h> contains inline functions that
require __do_div64, which is not linked into the ARM kernel
decompressor. This makes Risc PC zImages fail to build.

There is no need to use 64-bit division code here, so resolve this issue
by using plain standard addition and shift maths.

Hi, Helge,

I can confirm that this patch fixes the issue. Thank you for your
thorough investigation.

Ethan