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-rw-r--r--arch/arm64/Kconfig.debug8
-rw-r--r--arch/arm64/kernel/Makefile4
-rw-r--r--arch/arm64/kernel/head.S47
3 files changed, 58 insertions, 1 deletions
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index d1ebd46872fd..f7f38b1aab14 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -95,6 +95,14 @@ config DEBUG_ALIGN_RODATA
If in doubt, say N.
+config DEBUG_EFI
+ depends on EFI && DEBUG_INFO
+ bool "UEFI debugging"
+ help
+ Enable this option to include EFI specific debugging features into
+ the kernel that are only useful when using a debug build of the
+ UEFI firmware
+
source "drivers/hwtracing/coresight/Kconfig"
endmenu
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 7d66bbaafc0c..1606c6b2a280 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 += $(head-y) vmlinux.lds
+
+ifeq ($(CONFIG_DEBUG_EFI),y)
+AFLAGS_head.o += -DVMLINUX_PATH="\"$(realpath $(objtree)/vmlinux)\""
+endif
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index d3b8f92de5c5..c6cc82ec190b 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_EFI
+ .long efi_debug_table - _head // DebugTable
+ .long efi_debug_table_size
+#endif
+
// Section table
section_table:
@@ -195,6 +200,46 @@ section_table:
.short 0 // NumberOfLineNumbers (0 for executables)
.long 0xe0500020 // Characteristics (section flags)
+#ifdef CONFIG_DEBUG_EFI
+ /*
+ * 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.
+ */
+ __INITRODATA
+
+ .align 2
+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 0 // RVA
+ .long efi_debug_entry - _head // 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
+
/*
* EFI will load .text onwards at the 4k section alignment
* described in the PE/COFF header. To ensure that instruction
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