On Wed, Jul 30, 2014 at 11:59:03AM +0100, Ard Biesheuvel wrote:
> The static memory footprint of a kernel Image at boot is larger than the
> Image file itself. Things like .bss data and initial page tables are allocated
> statically but populated dynamically so their content is not contained in the
> Image file.
> 
> However, if EFI (or GRUB) has loaded the Image at precisely the desired offset
> of base of DRAM + TEXT_OFFSET, the Image will be booted in place, and we have
> to make sure that the allocation done by the PE/COFF loader is large enough.
> 
> Fix this by growing the PE/COFF .text section to cover the entire static
> memory footprint. The part of the section that is not covered by the payload
> will be zero initialised by the PE/COFF loader.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
> Acked-by: Mark Salter <msal...@redhat.com>

This looks sane to me and it seems we do the same for x86 as of
c7fb93ec51d4 (x86/efi: Include a .bss section within the PE/COFF
headers). So:

Acked-by: Mark Rutland <mark.rutl...@arm.com>

> ---
>  arch/arm64/kernel/head.S | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
> index 144f10567f82..b6ca95aee348 100644
> --- a/arch/arm64/kernel/head.S
> +++ b/arch/arm64/kernel/head.S
> @@ -151,7 +151,7 @@ optional_header:
>       .short  0x20b                           // PE32+ format
>       .byte   0x02                            // MajorLinkerVersion
>       .byte   0x14                            // MinorLinkerVersion
> -     .long   _edata - stext                  // SizeOfCode
> +     .long   _end - stext                    // SizeOfCode
>       .long   0                               // SizeOfInitializedData
>       .long   0                               // SizeOfUninitializedData
>       .long   efi_stub_entry - efi_head       // AddressOfEntryPoint
> @@ -169,7 +169,7 @@ extra_header_fields:
>       .short  0                               // MinorSubsystemVersion
>       .long   0                               // Win32VersionValue
>  
> -     .long   _edata - efi_head               // SizeOfImage
> +     .long   _end - efi_head                 // SizeOfImage
>  
>       // Everything before the kernel image is considered part of the header
>       .long   stext - efi_head                // SizeOfHeaders
> @@ -216,7 +216,7 @@ section_table:
>       .byte   0
>       .byte   0
>       .byte   0                       // end of 0 padding of section name
> -     .long   _edata - stext          // VirtualSize
> +     .long   _end - stext            // VirtualSize
>       .long   stext - efi_head        // VirtualAddress
>       .long   _edata - stext          // SizeOfRawData
>       .long   stext - efi_head        // PointerToRawData
> -- 
> 1.8.3.2
> 
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