[PATCH] efi_loader: Expose relocated address for gdb debugging purposes

[Heinrich Schuchardt]

On 3/24/22 17:22, Alexander von Gluck IV wrote:
> * If users want to debug EFI applications via qemu + GDB, they
>    need to know the relocated address of the application to
>    align their symbols to in GDB via add-symbol-file.
> * This exposes where EFI applications are relocated to enable
>    debugging EFI applications via qemu + gdb
> * Usage is generally determining the address, then
>    add-symbol-file (efi loader) (address)
> * The address can change, but is generally consistent with
>    the same qemu version and u-boot binary. (allowing you to
>    boot once, find the address, then reboot with qemu -s -S
> ---
>   lib/efi_loader/efi_image_loader.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
> index 773bd0677c..2b8c1ef464 100644
> --- a/lib/efi_loader/efi_image_loader.c
> +++ b/lib/efi_loader/efi_image_loader.c
> @@ -906,6 +906,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
>   			ret = EFI_OUT_OF_RESOURCES;
>   			goto err;
>   		}
> +		log_info("64-bit EFI image loaded at relocated address %p\n", efi_reloc);
> +
>   		handle->entry = efi_reloc + opt->AddressOfEntryPoint;
>   		rel_size = opt->DataDirectory[rel_idx].Size;
>   		rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
> @@ -922,6 +924,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
>   			ret = EFI_OUT_OF_RESOURCES;
>   			goto err;
>   		}
> +		log_info("32-bit EFI image loaded at relocated address %p\n", efi_reloc);
> +
>   		handle->entry = efi_reloc + opt->AddressOfEntryPoint;
>   		rel_size = opt->DataDirectory[rel_idx].Size;
>   		rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;

Do we really always need this output for every invokation of LoadImage()?

Writing test messages during the runtime of a menu driven program like
the UEFI SCT can be very disturbing.

Isn't it sufficient to show this output for binaries directly launched
by U-Boot?

Best regards

Heinrich