[PATCH v2 2/2] efi_loader: fix building aarch64 EFI binaries

[Heinrich Schuchardt]

While our EFI binaries execute without problems on EDK II they crash on
a Lenovo X13s. Let our binaries look more like what EDK II produces:

* move all writable data to a .data section
* align sections to 4 KiB boundaries (matching EFI page size)
* remove IMAGE_SCN_LNK_NRELOC_OVFL from .reloc section flags

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
---
v2:
	use constants for section flags
	remove IMAGE_SCN_LNK_NRELOC_OVFL from .reloc section flags
---
 arch/arm/lib/crt0_aarch64_efi.S  | 48 +++++++++++++++++++++++---------
 arch/arm/lib/elf_aarch64_efi.lds |  6 ++--
 2 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/arch/arm/lib/crt0_aarch64_efi.S b/arch/arm/lib/crt0_aarch64_efi.S
index b4fc263adf..da8db43828 100644
--- a/arch/arm/lib/crt0_aarch64_efi.S
+++ b/arch/arm/lib/crt0_aarch64_efi.S
@@ -25,7 +25,7 @@ pe_header:
 	.long	IMAGE_NT_SIGNATURE		/* 'PE' */
 coff_header:
 	.short	IMAGE_FILE_MACHINE_ARM64	/* AArch64 */
-	.short	2				/* nr_sections */
+	.short	3				/* nr_sections */
 	.long	0				/* TimeDateStamp */
 	.long	0				/* PointerToSymbolTable */
 	.long	0				/* NumberOfSymbols */
@@ -40,7 +40,7 @@ optional_header:
 	.short	IMAGE_NT_OPTIONAL_HDR64_MAGIC	/* PE32+ format */
 	.byte	0x02				/* MajorLinkerVersion */
 	.byte	0x14				/* MinorLinkerVersion */
-	.long	_edata - _start			/* SizeOfCode */
+	.long	_etext - _start			/* SizeOfCode */
 	.long	0				/* SizeOfInitializedData */
 	.long	0				/* SizeOfUninitializedData */
 	.long	_start - ImageBase		/* AddressOfEntryPoint */
@@ -48,7 +48,7 @@ optional_header:
 
 extra_header_fields:
 	.quad	0				/* ImageBase */
-	.long	0x200				/* SectionAlignment */
+	.long	0x1000				/* SectionAlignment */
 	.long	0x200				/* FileAlignment */
 	.short	0				/* MajorOperatingSystemVersion */
 	.short	0				/* MinorOperatingSystemVersion */
@@ -100,25 +100,47 @@ section_table:
 	.long	0			/* PointerToLineNumbers */
 	.short	0			/* NumberOfRelocations */
 	.short	0			/* NumberOfLineNumbers */
-	.long	0x42100040		/* Characteristics (section flags) */
-
+	/* Characteristics (section flags) */
+	.long	(IMAGE_SCN_MEM_READ | \
+		 IMAGE_SCN_MEM_DISCARDABLE | \
+		 IMAGE_SCN_CNT_INITIALIZED_DATA)
 
 	.ascii	".text"
 	.byte	0
 	.byte	0
 	.byte	0			/* end of 0 padding of section name */
-	.long	_edata - _start		/* VirtualSize */
+	.long	_etext - _start		/* VirtualSize */
 	.long	_start - ImageBase	/* VirtualAddress */
-	.long	_edata - _start		/* SizeOfRawData */
+	.long	_etext - _start		/* SizeOfRawData */
 	.long	_start - ImageBase	/* PointerToRawData */
+	.long	0			/* PointerToRelocations */
+	.long	0			/* PointerToLineNumbers */
+	.short	0			/* NumberOfRelocations */
+	.short	0			/* NumberOfLineNumbers */
+	/* Characteristics (section flags) */
+	.long	(IMAGE_SCN_MEM_READ | \
+		 IMAGE_SCN_MEM_EXECUTE | \
+		 IMAGE_SCN_CNT_CODE)
 
-	.long	0		/* PointerToRelocations (0 for executables) */
-	.long	0		/* PointerToLineNumbers (0 for executables) */
-	.short	0		/* NumberOfRelocations  (0 for executables) */
-	.short	0		/* NumberOfLineNumbers  (0 for executables) */
-	.long	0xe0500020	/* Characteristics (section flags) */
+	.ascii	".data"
+	.byte	0
+	.byte	0
+	.byte	0			/* end of 0 padding of section name */
+	.long	_data_size		/* VirtualSize */
+	.long	_data - ImageBase	/* VirtualAddress */
+	.long	_data_size		/* SizeOfRawData */
+	.long	_data - ImageBase	/* PointerToRawData */
+	.long	0			/* PointerToRelocations */
+	.long	0			/* PointerToLineNumbers */
+	.short	0			/* NumberOfRelocations */
+	.short	0			/* NumberOfLineNumbers */
+	.long	0xc0000040		/* Characteristics (section flags) */
+	/* Characteristics (section flags) */
+	.long	(IMAGE_SCN_MEM_WRITE | \
+		 IMAGE_SCN_MEM_READ | \
+		 IMAGE_SCN_CNT_INITIALIZED_DATA)
 
-	.align		9
+	.align		12
 _start:
 	stp		x29, x30, [sp, #-32]!
 	mov		x29, sp
diff --git a/arch/arm/lib/elf_aarch64_efi.lds b/arch/arm/lib/elf_aarch64_efi.lds
index c0604dad46..ffc6f6e604 100644
--- a/arch/arm/lib/elf_aarch64_efi.lds
+++ b/arch/arm/lib/elf_aarch64_efi.lds
@@ -18,11 +18,13 @@ SECTIONS
 		*(.gnu.linkonce.t.*)
 		*(.srodata)
 		*(.rodata*)
+		. = ALIGN(16);
+		*(.dynamic);
 		. = ALIGN(512);
 	}
 	_etext = .;
 	_text_size = . - _text;
-	.dynamic  : { *(.dynamic) }
+	. = ALIGN(4096);
 	.data : {
 		_data = .;
 		*(.sdata)
@@ -48,11 +50,11 @@ SECTIONS
 		_bss_end = .;
 		_edata = .;
 	}
+	_data_size = _edata - _data;
 	.rela.dyn : { *(.rela.dyn) }
 	.rela.plt : { *(.rela.plt) }
 	.rela.got : { *(.rela.got) }
 	.rela.data : { *(.rela.data) *(.rela.data*) }
-	_data_size = . - _etext;
 
 	. = ALIGN(4096);
 	.dynsym   : { *(.dynsym) }
-- 
2.37.2