The recommended answer, as the comment suggests, is to save it as .config
in the top-level source directory, and then run make xconfig
(GUI, easier) or make menuconfig
(TUI) on a 64-bit system.
That said, to simply switch from 32-bit to 64-bit without changing anything else, a little editing at the beginning is all that's needed. Compare:
# CONFIG_64BIT is not set
CONFIG_X86_32=y
# CONFIG_X86_64 is not set
CONFIG_OUTPUT_FORMAT="elf32-i386"
CONFIG_ARCH_DEFCONFIG="arch/x86/configs/i386_defconfig"
CONFIG_64BIT=y
# CONFIG_X86_32 is not set
CONFIG_X86_64=y
CONFIG_OUTPUT_FORMAT="elf64-x86-64"
CONFIG_ARCH_DEFCONFIG="arch/x86/configs/x86_64_defconfig"
- Note that
CONFIG_X86=y
is not touched.
.config
, I believemake menuconfig
reads it.