Commit c16173fa authored Jul 30, 2014 by Ard Biesheuvel Committed by Will Deacon Sep 08, 2014

arm64/efi: efistub: cover entire static mem footprint in PE/COFF .text



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.

Acked-by: Mark Salter <msalter@redhat.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Leif Lindholm <leif.lindholm@linaro.org>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

parent 113954c6

arch/arm64/kernel/head.S

+3 −3

Original line number	Diff line number	Diff line
		@@ -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

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