162306a36Sopenharmony_ci.. SPDX-License-Identifier: GPL-2.0 262306a36Sopenharmony_ci 362306a36Sopenharmony_ci===================================== 462306a36Sopenharmony_ciGeneral note on [U]EFI x86_64 support 562306a36Sopenharmony_ci===================================== 662306a36Sopenharmony_ci 762306a36Sopenharmony_ciThe nomenclature EFI and UEFI are used interchangeably in this document. 862306a36Sopenharmony_ci 962306a36Sopenharmony_ciAlthough the tools below are _not_ needed for building the kernel, 1062306a36Sopenharmony_cithe needed bootloader support and associated tools for x86_64 platforms 1162306a36Sopenharmony_ciwith EFI firmware and specifications are listed below. 1262306a36Sopenharmony_ci 1362306a36Sopenharmony_ci1. UEFI specification: http://www.uefi.org 1462306a36Sopenharmony_ci 1562306a36Sopenharmony_ci2. Booting Linux kernel on UEFI x86_64 platform requires bootloader 1662306a36Sopenharmony_ci support. Elilo with x86_64 support can be used. 1762306a36Sopenharmony_ci 1862306a36Sopenharmony_ci3. x86_64 platform with EFI/UEFI firmware. 1962306a36Sopenharmony_ci 2062306a36Sopenharmony_ciMechanics 2162306a36Sopenharmony_ci--------- 2262306a36Sopenharmony_ci 2362306a36Sopenharmony_ci- Build the kernel with the following configuration:: 2462306a36Sopenharmony_ci 2562306a36Sopenharmony_ci CONFIG_FB_EFI=y 2662306a36Sopenharmony_ci CONFIG_FRAMEBUFFER_CONSOLE=y 2762306a36Sopenharmony_ci 2862306a36Sopenharmony_ci If EFI runtime services are expected, the following configuration should 2962306a36Sopenharmony_ci be selected:: 3062306a36Sopenharmony_ci 3162306a36Sopenharmony_ci CONFIG_EFI=y 3262306a36Sopenharmony_ci CONFIG_EFIVAR_FS=y or m # optional 3362306a36Sopenharmony_ci 3462306a36Sopenharmony_ci- Create a VFAT partition on the disk 3562306a36Sopenharmony_ci- Copy the following to the VFAT partition: 3662306a36Sopenharmony_ci 3762306a36Sopenharmony_ci elilo bootloader with x86_64 support, elilo configuration file, 3862306a36Sopenharmony_ci kernel image built in first step and corresponding 3962306a36Sopenharmony_ci initrd. Instructions on building elilo and its dependencies 4062306a36Sopenharmony_ci can be found in the elilo sourceforge project. 4162306a36Sopenharmony_ci 4262306a36Sopenharmony_ci- Boot to EFI shell and invoke elilo choosing the kernel image built 4362306a36Sopenharmony_ci in first step. 4462306a36Sopenharmony_ci- If some or all EFI runtime services don't work, you can try following 4562306a36Sopenharmony_ci kernel command line parameters to turn off some or all EFI runtime 4662306a36Sopenharmony_ci services. 4762306a36Sopenharmony_ci 4862306a36Sopenharmony_ci noefi 4962306a36Sopenharmony_ci turn off all EFI runtime services 5062306a36Sopenharmony_ci reboot_type=k 5162306a36Sopenharmony_ci turn off EFI reboot runtime service 5262306a36Sopenharmony_ci 5362306a36Sopenharmony_ci- If the EFI memory map has additional entries not in the E820 map, 5462306a36Sopenharmony_ci you can include those entries in the kernels memory map of available 5562306a36Sopenharmony_ci physical RAM by using the following kernel command line parameter. 5662306a36Sopenharmony_ci 5762306a36Sopenharmony_ci add_efi_memmap 5862306a36Sopenharmony_ci include EFI memory map of available physical RAM 59