Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit ea6bc80d authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

arm64/efi: set PE/COFF section alignment to 4 KB 



Position independent AArch64 code needs to be linked and loaded at the
same relative offset from a 4 KB boundary, or adrp/add and adrp/ldr
pairs will not work correctly. (This is how PC relative symbol
references with a 4 GB reach are emitted)

We need to declare this in the PE/COFF header, otherwise the PE/COFF
loader may load the Image and invoke the stub at an offset which
violates this rule.

Reviewed-by: default avatarRoy Franz <roy.franz@linaro.org>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
parent 95b39596

arch/arm64/kernel/head.S

+10 −2
Original line number Diff line number Diff line
@@ -161,7 +161,7 @@ optional_header: 


extra_header_fields:

	.quad	0				// ImageBase

	.long	0x20				// SectionAlignment

	.long	0x1000				// SectionAlignment

	.long	0x8				// FileAlignment

	.short	0				// MajorOperatingSystemVersion

	.short	0				// MinorOperatingSystemVersion
@@ -228,7 +228,15 @@ section_table: 
	.short	0		// NumberOfRelocations  (0 for executables)

	.short	0		// NumberOfLineNumbers  (0 for executables)

	.long	0xe0500020	// Characteristics (section flags)

	.align 5



	/*

	 * EFI will load stext onwards at the 4k section alignment

	 * described in the PE/COFF header. To ensure that instruction

	 * sequences using an adrp and a :lo12: immediate will function

	 * correctly at this alignment, we must ensure that stext is

	 * placed at a 4k boundary in the Image to begin with.

	 */

	.align 12

#endif



ENTRY(stext)