Simon Glass of Chromium posted a *82-part* patch to the U-Boot list, with a port of U-Boot from 32-bit x86 to 64-bit x64 support. Quoting Simon’s initial message:
[PATCH 00/82] x86: Add initial support for 64-bit U-Boot
At present U-Boot runs entirely in 32-bit mode on x86, except for the initial switch from 16-bit mode. On 64-bit machines it is possible to run in 64-bit mode. This series starts the process of adding this support. The main benefit of 64-bit mode for a boot loader is direct access to all available memory. There are also more registers, but this makes very little difference. This feature is implemented by putting all of the 32-bit code in an SPL build. SPL then runs through all the init that has to be done in 32-bit mode, changes to 64-bit mode and then jumps to U-Boot proper. Typically the total code size increases slightly. For example, on link in 32-bit mode, U-Boot has around 480KB of code (admittedly with a large number of features enabled). In 64-bit mode, U-Boot falls to around 460KB, but SPL adds another 60KB, for a net increase of 40KB. Partly this is due to code duplication and partly it is due to the worse code density of 64-bit code on x86. Many major features are not implemented yet, for example:
– SDRAM sizing
– Booting linux
– FSP support
– EFI support
– SCSI device init
– Running video ROMs
Still, this is a big step forward towards full 64-bit support. To enable it, select CONFIG_X86_RUN_64BIT. This series is available at u-boot-x86/64-working.
91 files changed, 1796 insertions(+), 705 deletions(-)
See full description in the post:
http://lists.denx.de/pipermail/u-boot/2016-September/267925.html
Firmware Security 