arm64/efi: set PE/COFF section alignment to 4 KB (ea6bc80d) · Commits · 戴 / test

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:

Roy Franz <roy.franz@linaro.org> Acked-by:

Mark Rutland <mark.rutland@arm.com> Signed-off-by:

Ard Biesheuvel <ard.biesheuvel@linaro.org>

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)

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