EFI binaries should not contain sections that are both writable and executable. Separate the RX .text section from the RW .data section.
We currently don't created relocation sections (.rel.*) for our EFI binaries. Anyway these would have to be converted to PE/COFF relocations. Enumerate them under DISCARD and add a comment.
Correct the characteristics of the sections.
Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com --- v2: Consider that 32-bit arm uses .rel and not .rela relocations and discard them as they are cannot be used in EFI binaries. Correct the characteristics of the .reloc section. --- arch/arm/lib/crt0_arm_efi.S | 40 ++++++++++++++++++++++++++++-------- arch/arm/lib/elf_arm_efi.lds | 28 ++++++++++++++++++------- 2 files changed, 52 insertions(+), 16 deletions(-)
diff --git a/arch/arm/lib/crt0_arm_efi.S b/arch/arm/lib/crt0_arm_efi.S index 7a4e5dff75..7219c0f2fe 100644 --- a/arch/arm/lib/crt0_arm_efi.S +++ b/arch/arm/lib/crt0_arm_efi.S @@ -23,7 +23,7 @@ pe_header: .long IMAGE_NT_SIGNATURE /* 'PE' */ coff_header: .short IMAGE_FILE_MACHINE_THUMB /* Mixed ARM/Thumb */ - .short 2 /* nr_sections */ + .short 3 /* nr_sections */ .long 0 /* TimeDateStamp */ .long 0 /* PointerToSymbolTable */ .long 0 /* NumberOfSymbols */ @@ -98,22 +98,44 @@ 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 _text_size /* VirtualSize */ .long _start - image_base /* VirtualAddress */ - .long _edata - _start /* SizeOfRawData */ + .long _text_size /* 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)
- .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 - 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)
.align 12 _start: diff --git a/arch/arm/lib/elf_arm_efi.lds b/arch/arm/lib/elf_arm_efi.lds index 767ebda635..41440594aa 100644 --- a/arch/arm/lib/elf_arm_efi.lds +++ b/arch/arm/lib/elf_arm_efi.lds @@ -7,6 +7,12 @@
OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm") OUTPUT_ARCH(arm) + +PHDRS +{ + data PT_LOAD FLAGS(3); /* PF_W | PF_X */ +} + ENTRY(_start) SECTIONS { @@ -18,11 +24,13 @@ SECTIONS *(.gnu.linkonce.t.*) *(.srodata) *(.rodata*) + . = ALIGN(16); + *(.dynamic); . = ALIGN(512); } _etext = .; _text_size = . - _text; - .dynamic : { *(.dynamic) } + . = ALIGN(4096); .data : { _data = .; *(.sdata) @@ -47,14 +55,20 @@ SECTIONS . = ALIGN(512); _bss_end = .; _edata = .; - } - .rel.dyn : { *(.rel.dyn) } - .rel.plt : { *(.rel.plt) } - .rel.got : { *(.rel.got) } - .rel.data : { *(.rel.data) *(.rel.data*) } - _data_size = . - _etext; + } :data + _data_size = . - _data;
/DISCARD/ : { + /* + * We don't support relocations. These would have to be + * translated from ELF to PE format and added to the .reloc + * section. + */ + *(.rel.dyn) + *(.rel.plt) + *(.rel.got) + *(.rel.data) + *(.rel.data*) *(.rel.reloc) *(.eh_frame) *(.note.GNU-stack)