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

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Commit-ID:  aeffc4928ea21aab3c7be72f00e257799b661c29
Gitweb:     http://git.kernel.org/tip/aeffc4928ea21aab3c7be72f00e257799b661c29
Author:     Michael Brown <mbrown@xxxxxxxxxxxxxxxx>
AuthorDate: Thu, 10 Jul 2014 16:59:23 +0100
Committer:  Matt Fleming <matt.fleming@xxxxxxxxx>
CommitDate: Fri, 18 Jul 2014 21:24:02 +0100

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

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@xxxxxxxxxxxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
---
 arch/x86/boot/header.S | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 84c2234..1fdb350 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -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
--
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