[U-Boot] [PATCH] efi_loader: helloworld.c: Explicitly use .rodata for loaded_image_guid

[Heinrich Schuchardt]

On 12/11/2017 09:45 AM, Alexander Graf wrote:
> Commit bbf75dd9345d0b ("efi_loader: output load options in helloworld")
> introduced a const variable in efi_main() called loaded_image_guid which
> got populated from a constant struct.
> 
> While you would usually expect a compiler to realize that this variable
> should really just be a global pointer to .rodata, gcc disagrees and instead
> puts it on the stack. Unfortunately in some implementations of gcc it does
> so my calling memcpy() which we do not implement in our hello world
> environment.
> 
> So let's explicitly move it to a global variable which in turn puts it in
> .rodata reliably and gets rid of the memcpy().
> 
> Fixes: bbf75dd9345d0b ("efi_loader: output load options in helloworld")
> Reported-by: Florian Fainelli <f.fainelli at gmail.com>
> Signed-off-by: Alexander Graf <agraf at suse.de>
> ---
>   lib/efi_loader/helloworld.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/efi_loader/helloworld.c b/lib/efi_loader/helloworld.c
> index e59c24c788..b8c147d7f2 100644
> --- a/lib/efi_loader/helloworld.c
> +++ b/lib/efi_loader/helloworld.c
> @@ -13,6 +13,8 @@
>   #include <common.h>
>   #include <efi_api.h>
>   
> +static const efi_guid_t loaded_image_guid = LOADED_IMAGE_GUID;
> +
>   /*
>    * Entry point of the EFI application.
>    *
> @@ -26,7 +28,6 @@ efi_status_t EFIAPI efi_main(efi_handle_t handle,
>   	struct efi_simple_text_output_protocol *con_out = systable->con_out;
>   	struct efi_boot_services *boottime = systable->boottime;
>   	struct efi_loaded_image *loaded_image;
> -	const efi_guid_t loaded_image_guid = LOADED_IMAGE_GUID;
>   	efi_status_t ret;
>   
>   	con_out->output_string(con_out, L"Hello, world!\n");
> 
Reviewed-by: Heinrich Schuchardt <xypron.glpk at gmx.de>