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arch/x86/boot/zoffset.h

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

nm arch/x86/boot/compressed/vmlinux | \
  sed -n -e 's/^\([0-9a-fA-F]*\) [a-zA-Z] \(startup_32\|startup_64\|efi32_stub_entry\|efi64_stub_entry\|efi_pe_entry\|efi32_pe_entry\|input_data\|kernel_info\|_end\|_ehead\|_text\|z_.*\)$/#define ZO_ 0x/p' > \
  arch/x86/boot/zoffset.h

The prefix ZO_ apparently refers to the compressed kernel (see here and here).

The content of zoffset.h looks like

#define ZO__ehead 0x00000000000003a8
#define ZO__end 0x0000000000c55000
#define ZO__text 0x0000000000c186b0
#define ZO_efi32_pe_entry 0x0000000000c1f6e0
#define ZO_efi32_stub_entry 0x0000000000000190
#define ZO_efi64_stub_entry 0x0000000000000390
#define ZO_efi_pe_entry 0x0000000000c2079f
#define ZO_input_data 0x00000000000003a8
#define ZO_kernel_info 0x0000000000c26b30
#define ZO_startup_32 0x0000000000000000
#define ZO_startup_64 0x0000000000000200
#define ZO_z_input_len 0x0000000000c182fc
#define ZO_z_output_len 0x0000000002975b40

zoffset.h is a requisite for arch/x86/boot/tools/build to create arch/x86/boot/bzImage.

zoffset.h is included from arch/x86/boot/header.S.

arch/x86/boot/zoffset.h

See also