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Subject[PATCH 17/28] efi/x86: Add kernel preferred address to PE header
Date
From: Arvind Sankar <nivedita@alum.mit.edu>

Store the kernel's link address as ImageBase in the PE header. Note that
the PE specification requires the ImageBase to be 64k aligned. The
preferred address should almost always satisfy that, except for 32-bit
kernel if the configuration has been customized.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200303221205.4048668-4-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/boot/header.S | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 4ee25e28996f..736b3a0c9454 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -138,10 +138,12 @@ optional_header:
#endif

extra_header_fields:
+ # PE specification requires ImageBase to be 64k-aligned
+ .set image_base, (LOAD_PHYSICAL_ADDR + 0xffff) & ~0xffff
#ifdef CONFIG_X86_32
- .long 0 # ImageBase
+ .long image_base # ImageBase
#else
- .quad 0 # ImageBase
+ .quad image_base # ImageBase
#endif
.long 0x20 # SectionAlignment
.long 0x20 # FileAlignment
--
2.17.1
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