[U-Boot] [PATCH v2 19/63] x86: Add Kconfig options to build 64-bit U-Boot

[Bin Meng]

Hi Simon,

On Sun, Nov 20, 2016 at 4:25 AM, Simon Glass <sjg at chromium.org> wrote:
> Add a new CONFIG_X86_64 option which will eventually cause U-Boot to be
> built as a 64-bit application, with SPL doing the 16/32-bit init.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> Changes in v2: None
>
>  arch/x86/Kconfig | 46 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 46 insertions(+)
>

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>

One nits below:

> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 0884af2..5db8f13 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -5,6 +5,52 @@ config SYS_ARCH
>         default "x86"
>
>  choice
> +       prompt "Run U-Boot in 32/64-bit mode"
> +       default X86_RUN_32BIT
> +       help
> +         U-Boot can be built as a 32-bit binary which runs in 32-bit mode
> +         even on 64-bit machines. In this case SPL is not used, and U-Boot
> +         runs directly from the reset vector (via 16-bit start-up).
> +
> +         Alternatively it can be run as a 64-bit binary, thus requiring a
> +         64-bit machine. In this case SPL runs in 32-bit mode (via 16-bit
> +         start-up) then jumps to U-Boot in 64-bit mode.
> +
> +         For now, 32-bit mode is recommended, as 64-bit is still
> +         experimental and is missing a lot of features.
> +
> +config X86_RUN_32BIT
> +       bool "32-bit"
> +        help

nits: "help" is not aligned

> +         Build U-Boot as a 32-bit binary with no SPL. This is the currently
> +         supported normal setup. U-Boot will stay in 32-bit mode even on
> +         64-bit machines. When booting a 64-bit kernel, U-Boot will switch
> +         to 64-bit just before starting the kernel. Only the bottom 4GB of
> +         memory can be accessed through normal means, although
> +         arch_phys_memset() can be used for basic access to other memory.
> +
> +config X86_RUN_64BIT
> +       bool "64-bit"
> +       select X86_64
> +       select SUPPORT_SPL
> +       select SPL
> +       select SPL_SEPARATE_BSS
> +       help
> +         Build U-Boot as a 64-bit binary with a 32-bit SPL. This is
> +         experimental and many features are missing. U-Boot SPL starts up,
> +         runs through the 16-bit and 32-bit init, then switches to 64-bit
> +         mode and jumps to U-Boot proper.
> +
> +endchoice
> +
> +config X86_64
> +       bool
> +
> +config SPL_X86_64
> +       bool
> +       depends on SPL
> +
> +choice
>         prompt "Mainboard vendor"
>         default VENDOR_EMULATION
>
> --

Regards,
Bin