Subject: [PATCH 2/2] efi/arm64: increase the PE/COFF alignment so the kernel can run in place

From: Ard Biesheuvel <[email-masked]>
Date: Thu, 26 Mar 2020 17:59:05 +0100

Update the PE/COFF metadata so that the UEFI image loader will load the
kernel image at an offset that allows it to execute in place.

Signed-off-by: Ard Biesheuvel <[email-masked]>
---
 arch/arm64/kernel/efi-header.S | 2 +-
 arch/arm64/kernel/image-vars.h | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/efi-header.S b/arch/arm64/kernel/efi-header.S
index 914999ccaf8a..f9ee1c2a5fd6 100644
--- a/arch/arm64/kernel/efi-header.S
+++ b/arch/arm64/kernel/efi-header.S
@@ -32,7 +32,7 @@ optional_header:
 
 extra_header_fields:
 	.quad	0					// ImageBase
-	.long	SZ_4K					// SectionAlignment
+	.long	PECOFF_SECTION_ALIGNMENT		// SectionAlignment
 	.long	PECOFF_FILE_ALIGNMENT			// FileAlignment
 	.short	0					// MajorOperatingSystemVersion
 	.short	0					// MinorOperatingSystemVersion
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index be0a63ffed23..7a7fa3ba7b2f 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -15,6 +15,13 @@
 __efistub_kernel_size		= _edata - _text;
 __efistub_primary_entry_offset	= primary_entry - _text;
 
+#ifndef CONFIG_RELOCATABLE
+PECOFF_SECTION_ALIGNMENT = SZ_4K;
+#elif THREAD_ALIGN > SEGMENT_ALIGN
+PECOFF_SECTION_ALIGNMENT = THREAD_ALIGN;
+#else
+PECOFF_SECTION_ALIGNMENT = SEGMENT_ALIGN;
+#endif
 
 /*
  * The EFI stub has its own symbol namespace prefixed by __efistub_, to
-- 
2.17.1

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