[PATCH v2 2/3] arm64/efi: efistub: cover entire static mem footprint in PE/COFF .text
Mark Rutland
mark.rutland at arm.com
Thu Aug 14 04:31:25 PDT 2014
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.biesheuvel at linaro.org>
> Acked-by: Mark Salter <msalter at 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.rutland at 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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