[U-Boot] [PATCH 40/48] x86: Add support for passing tables into U-Boot

[Bin Meng]

Hi Simon,

On Wed, Jul 22, 2015 at 11:49 PM, Simon Glass <sjg at chromium.org> wrote:
> The EFI stub provides information to U-Boot in a table. This includes the
> memory map which is needed to decide where to relocate U-Boot. Collect this
> information in the early init code and store it in global_data.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
>  arch/x86/cpu/start.S               | 9 +++++++++
>  arch/x86/include/asm/global_data.h | 1 +
>  arch/x86/lib/asm-offsets.c         | 1 +
>  3 files changed, 11 insertions(+)
>
> diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S
> index 7ef8b88..356c1a5 100644
> --- a/arch/x86/cpu/start.S
> +++ b/arch/x86/cpu/start.S
> @@ -53,6 +53,9 @@ _start:
>         /* Save BIST */
>         movl    %eax, %ebp
>

What about the %eax in the EFI_STUB case? %eax already gets corrupted before.

> +       /* Save table pointer */
> +       movl    %ecx, %esi
> +
>         /* Load the segement registers to match the GDT loaded in start16.S */
>         movl    $(X86_GDT_ENTRY_32BIT_DS * X86_GDT_ENTRY_SIZE), %eax
>         movw    %ax, %fs
> @@ -129,7 +132,13 @@ car_init_ret:
>         movl    %esi, (%edx)
>
>  skip_hob:
> +#else
> +       /* Store table pointer */
> +       movl    %esp, %edx
> +       addl    $GD_TABLE, %edx
> +       movl    %esi, (%edx)
>  #endif
> +
>         /* Setup first parameter to setup_gdt, pointer to global_data */
>         movl    %esp, %eax
>
> diff --git a/arch/x86/include/asm/global_data.h b/arch/x86/include/asm/global_data.h
> index 6df6a78..ca32046 100644
> --- a/arch/x86/include/asm/global_data.h
> +++ b/arch/x86/include/asm/global_data.h
> @@ -69,6 +69,7 @@ struct arch_global_data {
>         char *mrc_output;
>         unsigned int mrc_output_len;
>         void *gdt;                      /* Global descriptor table */
> +       ulong table;                    /* Table pointer from previous loader */
>  };
>
>  #endif
> diff --git a/arch/x86/lib/asm-offsets.c b/arch/x86/lib/asm-offsets.c
> index 70ccf1b..9da04dd 100644
> --- a/arch/x86/lib/asm-offsets.c
> +++ b/arch/x86/lib/asm-offsets.c
> @@ -21,5 +21,6 @@ int main(void)
>  #ifdef CONFIG_HAVE_FSP
>         DEFINE(GD_HOB_LIST, offsetof(gd_t, arch.hob_list));
>  #endif
> +       DEFINE(GD_TABLE, offsetof(gd_t, arch.table));
>         return 0;
>  }
> --

Regards,
Bin