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x86/efi: Request desired alignment via the PE/COFF headers

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The EFI boot stub goes to great pains to relocate the kernel image to
an appropriately aligned address, as indicated by the ->kernel_alignment
field in the bzImage header.  However, for the PE stub entry case, we
can request that the EFI PE/COFF loader do the work for us.

Fix by exposing the desired alignment via the SectionAlignment field
in the PE/COFF headers.  Despite its name, this field provides an
overall alignment requirement for the loaded file.  (Naturally, the
FileAlignment field describes the alignment for individual sections.)

There is no way in the PE/COFF headers to express the concept of
min_alignment; we therefore do not expose the minimum (as opposed to
preferred) alignment.

Signed-off-by: Michael Brown <mbrown@fensystems.co.uk>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
This commit is contained in:
Michael Brown 2014-07-10 16:59:23 +01:00 committed by Matt Fleming
parent fb86b2440d
commit aeffc4928e
1 changed files with 1 additions and 1 deletions
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arch/x86/boot/header.S
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@ -155,7 +155,7 @@ extra_header_fields:
#else
.quad 0 # ImageBase
#endif
.long 0x20 # SectionAlignment
.long CONFIG_PHYSICAL_ALIGN # SectionAlignment
.long 0x20 # FileAlignment
.word 0 # MajorOperatingSystemVersion
.word 0 # MinorOperatingSystemVersion