[PATCH 31/32] efi: arm: Simplify the crt0 file and update link script
Simon Glass
sjg at chromium.org
Mon Feb 3 18:42:24 CET 2025
We don't need to manually add the PE header, since binutils has support
for this now. Remove it to simplify the file.
Set the link-target to efi-app-aarch64 so that binutils knows what to
do. Add rules to pick up the arm64 files.
Make some updates to the link-script for arm64, so this all works:
- Pass .hash .eh_frame and .reloc sections through to objcopy
- Put RELA pieces into a single section
- Put linker lists into .data
- Embed the dtb
Note that it does not seem to be possible to use this approach with arm,
so this is left alone.
Signed-off-by: Simon Glass <sjg at chromium.org>
---
arch/arm/config.mk | 10 ++
arch/arm/cpu/armv8/config.mk | 2 +-
arch/arm/lib/crt0_aarch64_efi.S | 156 +++++--------------------------
arch/arm/lib/elf_aarch64_efi.lds | 49 +++++++---
4 files changed, 70 insertions(+), 147 deletions(-)
diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 20f4d41f2c3..a786709f3b5 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -149,6 +149,9 @@ OBJCOPYFLAGS += -j .text -j .secure_text -j .secure_data -j .rodata -j .hash \
-j .binman_sym_table -j .text_rest
endif
+OBJCOPYFLAGS_EFI += $(OBJCOPYFLAGS) -j .dynamic -j .rela -j .reloc \
+ -j .embedded_dtb
+
# if a dtb section exists we always have to include it
# there are only two cases where it is generated
# 1) OF_EMBEDED is turned on
@@ -178,6 +181,13 @@ endif
endif
endif
+ifdef CONFIG_ARM64
+EFI_LDS := elf_aarch64_efi.lds
+EFI_CRT0 := crt0_aarch64_efi.o
+EFI_RELOC := reloc_aarch64_efi.o
+EFI_TARGET := --target=efi-app-aarch64
+else
EFI_LDS := elf_arm_efi.lds
EFI_CRT0 := crt0_arm_efi.o
EFI_RELOC := reloc_arm_efi.o
+endif
diff --git a/arch/arm/cpu/armv8/config.mk b/arch/arm/cpu/armv8/config.mk
index cf0b89819d5..25d7ea08fce 100644
--- a/arch/arm/cpu/armv8/config.mk
+++ b/arch/arm/cpu/armv8/config.mk
@@ -13,7 +13,7 @@ EFI_RELOC := reloc_aarch64_efi.o
LDSCRIPT_EFI := $(srctree)/arch/arm/lib/elf_aarch64_efi.lds
EFISTUB := crt0_aarch64_efi.o reloc_aarch64_efi.o
-OBJCOPYFLAGS_EFI += --target=pei-aarch64-little
+OBJCOPYFLAGS_EFI += -O binary --target=efi-app-aarch64
EFIPAYLOAD_BFDTARGET := pei-aarch64-little
EFIPAYLOAD_BFDARCH := aarch64
LDFLAGS_EFI_PAYLOAD := -Bsymbolic -Bsymbolic-functions -shared --no-undefined \
diff --git a/arch/arm/lib/crt0_aarch64_efi.S b/arch/arm/lib/crt0_aarch64_efi.S
index a1888cbb1e4..88f8449bb03 100644
--- a/arch/arm/lib/crt0_aarch64_efi.S
+++ b/arch/arm/lib/crt0_aarch64_efi.S
@@ -10,140 +10,11 @@
#include <asm-generic/pe.h>
- .section .text.head
-
- /*
- * Magic "MZ" signature for PE/COFF
- */
- .globl image_base
-image_base:
- .short IMAGE_DOS_SIGNATURE /* 'MZ' */
- .skip 54 /* 'MZ' + pad + offset == 64 */
- .long LINUX_ARM64_MAGIC /* For GRUB's linux command */
- .long pe_header - image_base /* Offset to the PE header */
-pe_header:
- .long IMAGE_NT_SIGNATURE /* 'PE' */
-coff_header:
- .short IMAGE_FILE_MACHINE_ARM64 /* AArch64 */
- .short 3 /* nr_sections */
- .long 0 /* TimeDateStamp */
- .long 0 /* PointerToSymbolTable */
- .long 0 /* NumberOfSymbols */
- .short section_table - optional_header /* SizeOfOptionalHeader */
- /* Characteristics */
- .short (IMAGE_FILE_EXECUTABLE_IMAGE | \
- IMAGE_FILE_LINE_NUMS_STRIPPED | \
- IMAGE_FILE_LOCAL_SYMS_STRIPPED | \
- IMAGE_FILE_LARGE_ADDRESS_AWARE | \
- IMAGE_FILE_DEBUG_STRIPPED)
-optional_header:
- .short IMAGE_NT_OPTIONAL_HDR64_MAGIC /* PE32+ format */
- .byte 0x02 /* MajorLinkerVersion */
- .byte 0x14 /* MinorLinkerVersion */
- .long _etext - _start /* SizeOfCode */
- .long 0 /* SizeOfInitializedData */
- .long 0 /* SizeOfUninitializedData */
- .long _start - image_base /* AddressOfEntryPoint */
- .long _start - image_base /* BaseOfCode */
-
-extra_header_fields:
- .quad 0 /* image_base */
- .long 0x1000 /* SectionAlignment */
- .long 0x200 /* FileAlignment */
- .short 0 /* MajorOperatingSystemVersion */
- .short 0 /* MinorOperatingSystemVersion */
- .short 0 /* MajorImageVersion */
- .short 0 /* MinorImageVersion */
- .short 0 /* MajorSubsystemVersion */
- .short 0 /* MinorSubsystemVersion */
- .long 0 /* Win32VersionValue */
-
- .long _edata - image_base /* SizeOfImage */
-
- /*
- * Everything before the kernel image is considered part of the header
- */
- .long _start - image_base /* SizeOfHeaders */
- .long 0 /* CheckSum */
- .short IMAGE_SUBSYSTEM_EFI_APPLICATION /* Subsystem */
-#if CONFIG_VENDOR_EFI
- .short 0 /* DllCharacteristics */
-#else
- .short IMAGE_DLLCHARACTERISTICS_NX_COMPAT
-#endif
- .quad 0 /* SizeOfStackReserve */
- .quad 0 /* SizeOfStackCommit */
- .quad 0 /* SizeOfHeapReserve */
- .quad 0 /* SizeOfHeapCommit */
- .long 0 /* LoaderFlags */
- .long 0x6 /* NumberOfRvaAndSizes */
-
- .quad 0 /* ExportTable */
- .quad 0 /* ImportTable */
- .quad 0 /* ResourceTable */
- .quad 0 /* ExceptionTable */
- .quad 0 /* CertificationTable */
- .quad 0 /* BaseRelocationTable */
-
- /* Section table */
-section_table:
-
- /*
- * The EFI application loader requires a relocation section
- * because EFI applications must be relocatable. This is a
- * dummy section as far as we are concerned.
- */
- .ascii ".reloc"
- .byte 0
- .byte 0 /* end of 0 padding of section name */
- .long 0
- .long 0
- .long 0 /* SizeOfRawData */
- .long 0 /* PointerToRawData */
- .long 0 /* PointerToRelocations */
- .long 0 /* PointerToLineNumbers */
- .short 0 /* NumberOfRelocations */
- .short 0 /* NumberOfLineNumbers */
- /* 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 _etext - _start /* VirtualSize */
- .long _start - image_base /* VirtualAddress */
- .long _etext - _start /* SizeOfRawData */
- .long _start - image_base /* 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)
-
- .ascii ".data"
- .byte 0
- .byte 0
- .byte 0 /* end of 0 padding of section name */
- .long _data_size /* VirtualSize */
- .long _data - image_base /* VirtualAddress */
- .long _data_size /* SizeOfRawData */
- .long _data - image_base /* PointerToRawData */
- .long 0 /* PointerToRelocations */
- .long 0 /* PointerToLineNumbers */
- .short 0 /* NumberOfRelocations */
- .short 0 /* NumberOfLineNumbers */
- /* Characteristics (section flags) */
- .long (IMAGE_SCN_MEM_WRITE | \
- IMAGE_SCN_MEM_READ | \
- IMAGE_SCN_CNT_INITIALIZED_DATA)
-
+ .text
.align 12
+
+ .globl _start
+ .type _start,%function
_start:
stp x29, x30, [sp, #-32]!
mov x29, sp
@@ -160,3 +31,22 @@ _start:
0: ldp x29, x30, [sp], #32
ret
+
+ /*
+ * hand-craft a dummy .reloc section so EFI knows it's a relocatable
+ * executable:
+ */
+ .data
+dummy: .4byte 0
+
+#define IMAGE_REL_ABSOLUTE 0
+ .section .reloc, "a"
+label1:
+ .4byte dummy-label1 // Page RVA
+ .4byte 12 // Block Size (2*4+2*2), must be aligned by 32 Bits
+ .2byte (IMAGE_REL_ABSOLUTE<<12) + 0 // reloc for dummy
+ .2byte (IMAGE_REL_ABSOLUTE<<12) + 0 // reloc for dummy
+
+#if defined(__ELF__) && defined(__linux__)
+ .section .note.GNU-stack,"",%progbits
+#endif
diff --git a/arch/arm/lib/elf_aarch64_efi.lds b/arch/arm/lib/elf_aarch64_efi.lds
index 5dd98091698..2241bea4dc1 100644
--- a/arch/arm/lib/elf_aarch64_efi.lds
+++ b/arch/arm/lib/elf_aarch64_efi.lds
@@ -7,18 +7,19 @@
OUTPUT_FORMAT("elf64-littleaarch64", "elf64-littleaarch64", "elf64-littleaarch64")
OUTPUT_ARCH(aarch64)
-
-PHDRS
-{
- data PT_LOAD FLAGS(3); /* SHF_WRITE | SHF_ALLOC */
-}
-
ENTRY(_start)
SECTIONS
{
- .text 0x0 : {
+ . = 0;
+ image_base = .;
+ /* .hash and/or .gnu.hash MUST come first! */
+ .hash : { *(.hash) }
+ .gnu.hash : { *(.gnu.hash) }
+ . = ALIGN(4096);
+ .eh_frame : { *(.eh_frame) }
+ . = ALIGN(4096);
+ .text : {
_text = .;
- *(.text.head)
*(.text)
*(.text.*)
*(.gnu.linkonce.t.*)
@@ -28,12 +29,12 @@ SECTIONS
*(.dynamic);
. = ALIGN(512);
}
- .rela.dyn : { *(.rela.dyn) }
- .rela.plt : { *(.rela.plt) }
- .rela.got : { *(.rela.got) }
- .rela.data : { *(.rela.data) *(.rela.data*) }
_etext = .;
_text_size = . - _text;
+ . = ALIGN(65536);
+ .reloc : {
+ KEEP (*(.reloc))
+ }
. = ALIGN(4096);
.data : {
_data = .;
@@ -43,6 +44,10 @@ SECTIONS
*(.data.*)
*(.got.plt)
*(.got)
+ /* U-Boot lists and device tree */
+ . = ALIGN(8);
+ *(SORT(__u_boot_list*));
+ . = ALIGN(8);
/*
* The EFI loader doesn't seem to like a .bss section, so we
@@ -59,9 +64,24 @@ SECTIONS
. = ALIGN(512);
_bss_end = .;
_edata = .;
- } :data
+ _end = .;
+ }
_data_size = _edata - _data;
+ . = ALIGN(4096);
+ .rela : {
+ *(.rela.text*)
+ *(.rela.data*)
+ *(.rela.got)
+ *(.rela.dyn)
+ *(.rela.stab)
+ *(.rela.init_array*)
+ *(.rela.fini_array*)
+ *(.rela.ctors*)
+ *(.rela.dtors*)
+ *(.rela__u_boot_list*)
+ }
+
. = ALIGN(4096);
.dynsym : { *(.dynsym) }
. = ALIGN(4096);
@@ -73,5 +93,8 @@ SECTIONS
*(.eh_frame)
*(.note.GNU-stack)
}
+ .embedded_dtb : {
+ *(.embedded_dtb)
+ }
.comment 0 : { *(.comment) }
}
--
2.43.0
More information about the U-Boot
mailing list