[PATCH 7/7] arm: efi: add PE/COFF debug table to EFI header
From: Ard Biesheuvel <hidden>
Date: 2017-05-30 18:36:47
Also in:
linux-efi
Subsystem:
arm port, extensible firmware interface (efi), the rest · Maintainers:
Russell King, Ard Biesheuvel, Linus Torvalds
This updates the PE/COFF header to emit the absolute path to the decompressor vmlinux ELF file into a so-called NB10 Codeview entry. This is hugely helpful when debugging the firmware->stub handover. Signed-off-by: Ard Biesheuvel <redacted> --- arch/arm/boot/compressed/Makefile | 4 ++ arch/arm/boot/compressed/efi-header.S | 40 ++++++++++++++++++++ 2 files changed, 44 insertions(+)
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index d50430c40045..6b978bdbac3e 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile@@ -196,3 +196,7 @@ AFLAGS_hyp-stub.o := -Wa,-march=armv7-a $(obj)/hyp-stub.S: $(srctree)/arch/$(SRCARCH)/kernel/hyp-stub.S $(call cmd,shipped) + +ifeq ($(CONFIG_EFI)$(CONFIG_DEBUG_INFO),yy) +AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(obj)/vmlinux)\"" +endif
diff --git a/arch/arm/boot/compressed/efi-header.S b/arch/arm/boot/compressed/efi-header.S
index a0567ed366c6..3dedaab49cb8 100644
--- a/arch/arm/boot/compressed/efi-header.S
+++ b/arch/arm/boot/compressed/efi-header.S@@ -124,6 +124,46 @@ section_table: .set section_count, (. - section_table) / 40 +#ifdef CONFIG_DEBUG_INFO + /* + * The debug table is referenced via its Relative Virtual Address (RVA), + * which is only defined for those parts of the image that are covered + * by a section declaration. Since this header is not covered by any + * section, the debug table must be emitted elsewhere. So stick it in + * the .init.rodata section instead. + * + * Note that the EFI debug entry itself may legally have a zero RVA, + * which means we can simply put it right after the section headers. + */ + .section ".rodata", #alloc + + .align 2 +efi_debug_table: + // EFI_IMAGE_DEBUG_DIRECTORY_ENTRY + .long 0 @ Characteristics + .long 0 @ TimeDateStamp + .short 0 @ MajorVersion + .short 0 @ MinorVersion + .long IMAGE_DEBUG_TYPE_CODEVIEW @ Type + .long efi_debug_entry_size @ SizeOfData + .long 0 @ RVA + .long efi_debug_entry - start @ FileOffset + + .set efi_debug_table_size, . - efi_debug_table + .previous + +efi_debug_entry: + // EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY + .ascii "NB10" @ Signature + .long 0 @ Unknown + .long 0 @ Unknown2 + .long 0 @ Unknown3 + + .asciz VMLINUX_PATH + + .set efi_debug_entry_size, . - efi_debug_entry +#endif + .align 12 __efi_start: .text
--
2.9.3