[PATCH v4 13/29] efi: lmb: Avoid access to _start

[Caleb Connolly]

On 2/15/25 04:22, Simon Glass wrote:
> The app does not have this symbol. Also the memory where the app is
> loaded is not under U-Boot's control.
> 
> There is no sense in relocating from one alloced region to another.
> U-Boot is not able to relocate to the top of memory, nor decide what
> other parts of memory are used for.
> 
> For these reasons, the EFI app skips relocation. It is not running at
> the address pointed to by the _start symbol.

is there a symbol or not? If there is could we have some "relocate in 
place" mechanism so that it's valid? When I (finally...) get around to 
re-sending the symbol lookup support it would be nice if it worked for 
the EFI app, and it relies on _start.
> 
> So disable this reservation for the EFI app.
> 
> Signed-off-by: Simon Glass <sjg at chromium.org>
> Reviewed-by: Tom Rini <trini at konsulko.com>
> ---
> 
> (no changes since v2)
> 
> Changes in v2:
> - Expand commit message to explains that EFI_APP skips relocation
> 
>   lib/lmb.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/lmb.c b/lib/lmb.c
> index 588787d2a90..420eae4d0b8 100644
> --- a/lib/lmb.c
> +++ b/lib/lmb.c
> @@ -560,7 +560,8 @@ static void lmb_reserve_uboot_region(void)
>   		lmb_reserve_flags(rsv_start, bank_end - rsv_start + 1,
>   				  LMB_NOOVERWRITE);
>   
> -		if (gd->flags & GD_FLG_SKIP_RELOC)
> +		if (!IS_ENABLED(CONFIG_EFI_APP) &&
> +		    (gd->flags & GD_FLG_SKIP_RELOC))
>   			lmb_reserve_flags((phys_addr_t)(uintptr_t)_start,
>   					  gd->mon_len, LMB_NOOVERWRITE);
>   

-- 
Caleb (they/them)