Re: [PATCH 1/1] riscv: efi: Set NX compat flag in PE/COFF header

[Emil Renner Berthing]

Heinrich Schuchardt wrote:
> The IMAGE_DLLCHARACTERISTICS_NX_COMPAT informs the firmware that the
> EFI binary does not rely on pages that are both executable and
> writable.
>
> The flag is used by some distro versions of GRUB to decide if the EFI
> binary may be executed.
>
> As the Linux kernel neither has RWX sections nor needs RWX pages for
> relocation we should set the flag.
>
> Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@xxxxxxxxxxxxx>

Makes sense to me. This was applied a year ago on arm64:

  3c66bb1918c2 ("arm64: efi: Set NX compat flag in PE/COFF header")

..and before that on x86

  24b72bb12e84 ("efi: x86: Set the NX-compatibility flag in the PE header")

Reviewed-by: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>

> ---
>  arch/riscv/kernel/efi-header.S | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/efi-header.S b/arch/riscv/kernel/efi-header.S
> index 515b2dfbca75..c5f17c2710b5 100644
> --- a/arch/riscv/kernel/efi-header.S
> +++ b/arch/riscv/kernel/efi-header.S
> @@ -64,7 +64,7 @@ extra_header_fields:
>  	.long	efi_header_end - _start			// SizeOfHeaders
>  	.long	0					// CheckSum
>  	.short	IMAGE_SUBSYSTEM_EFI_APPLICATION		// Subsystem
> -	.short	0					// DllCharacteristics
> +	.short	IMAGE_DLL_CHARACTERISTICS_NX_COMPAT	// DllCharacteristics
>  	.quad	0					// SizeOfStackReserve
>  	.quad	0					// SizeOfStackCommit
>  	.quad	0					// SizeOfHeapReserve
> --
> 2.45.2
>
>
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