From: ard.biesheuvel@linaro.org (Ard Biesheuvel)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH 2/2] efi: arm64: add vmlinux debug link to the Image binary
Date: Wed, 19 Oct 2016 12:40:32 +0100 [thread overview]
Message-ID: <1476877232-24308-3-git-send-email-ard.biesheuvel@linaro.org> (raw)
In-Reply-To: <1476877232-24308-1-git-send-email-ard.biesheuvel@linaro.org>
When building with debugging symbols, take the absolute path to the
vmlinux binary and add it to the special PE/COFF debug table entry.
This allows a debug EFI build to find the vmlinux binary, which is
very helpful in debugging, given that the offset where the Image is
first loaded by EFI is highly unpredictable.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
arch/arm64/kernel/Makefile | 4 +++
arch/arm64/kernel/head.S | 34 +++++++++++++++++++-
arch/arm64/kernel/image.h | 3 ++
3 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 7d66bbaafc0c..1def85599fdb 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -55,3 +55,7 @@ obj-y += $(arm64-obj-y) vdso/ probes/
obj-m += $(arm64-obj-m)
head-y := head.o
extra-y += $(head-y) vmlinux.lds
+
+ifneq ($(CONFIG_DEBUG_INFO),)
+AFLAGS_head.o += -DVMLINUX_PATH="\"$(shell readlink -f $(objtree)/vmlinux)\""
+endif
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 427f6d3f084c..2f3fbd966de7 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -149,7 +149,7 @@ extra_header_fields:
.quad 0 // SizeOfHeapReserve
.quad 0 // SizeOfHeapCommit
.long 0 // LoaderFlags
- .long 0x6 // NumberOfRvaAndSizes
+ .long (section_table - .) / 8 // NumberOfRvaAndSizes
.quad 0 // ExportTable
.quad 0 // ImportTable
@@ -158,6 +158,11 @@ extra_header_fields:
.quad 0 // CertificationTable
.quad 0 // BaseRelocationTable
+#ifdef CONFIG_DEBUG_INFO
+ .long efi_debug_table - _head // DebugTable
+ .long efi_debug_table_size
+#endif
+
// Section table
section_table:
@@ -206,6 +211,33 @@ section_table:
efi_header_end:
#endif
+#ifdef CONFIG_DEBUG_INFO
+ __INITDATA
+
+efi_debug_table:
+ // EFI_IMAGE_DEBUG_DIRECTORY_ENTRY
+ .long 0 // Characteristics
+ .long 0 // TimeDateStamp
+ .short 0 // MajorVersion
+ .short 0 // MinorVersion
+ .long 2 // Type == EFI_IMAGE_DEBUG_TYPE_CODEVIEW
+ .long efi_debug_entry_size // SizeOfData
+ .long efi_debug_entry_offset // RVA
+ .long efi_debug_entry_offset // FileOffset
+
+ENTRY(efi_debug_entry)
+ // EFI_IMAGE_DEBUG_CODEVIEW_NB10_ENTRY
+ .long 0x3031424E // Signature
+ .long 0 // Unknown
+ .long 0 // Unknown2
+ .long 0 // Unknown3
+
+ .asciz VMLINUX_PATH
+
+ .set efi_debug_entry_size, . - efi_debug_entry
+ .set efi_debug_table_size, . - efi_debug_table
+#endif
+
__INIT
/*
diff --git a/arch/arm64/kernel/image.h b/arch/arm64/kernel/image.h
index c7fcb232fe47..ad5406f011c2 100644
--- a/arch/arm64/kernel/image.h
+++ b/arch/arm64/kernel/image.h
@@ -116,6 +116,9 @@ __efistub__end = KALLSYMS_HIDE(_end);
__efistub__edata = KALLSYMS_HIDE(_edata);
__efistub_screen_info = KALLSYMS_HIDE(screen_info);
+#ifdef CONFIG_DEBUG_INFO
+efi_debug_entry_offset = efi_debug_entry - _text;
+#endif
#endif
#endif /* __ASM_IMAGE_H */
--
2.7.4
prev parent reply other threads:[~2016-10-19 11:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-19 11:40 [RFC PATCH 0/2] efi/arm64: add vmlinux link to PE/COFF debug table Ard Biesheuvel
2016-10-19 11:40 ` [RFC PATCH 1/2] efi: libstub: preserve .debug sections after absolute relocation check Ard Biesheuvel
2016-10-19 12:55 ` Cohen, Eugene
2016-10-19 11:40 ` Ard Biesheuvel [this message]
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