Search notes:

arch/x86/boot/voffset.h

arch/x86/boot/zoffset.h is created when the kernel is made with the following command (Linux version 6.5):

nm vmlinux | sed -n -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(_text\|__bss_start\|_end\)$/#define VO_ _AC(0x,UL)/p' > arch/x86/boot/compressed/../voffset.h

The prefix VO_ apparently refers to the uncompressed kernel (see here and here).

The content of voffset.h looks like:

#define VO___bss_start _AC(0xffffffff834b2000,UL)
#define VO__end _AC(0xffffffff83830000,UL)
#define VO__text _AC(0xffffffff81000000,UL)

voffset.h is included from arch/x86/boot/header.S and arch/x86/boot/compressed/misc.c.

arch/x86/boot/voffset.h

See also