From 81a0bc39ea1960bbf8ece6a895d7cfd2d9efa28a Mon Sep 17 00:00:00 2001 From: Roy Franz Date: Wed, 23 Sep 2015 20:17:54 -0700 Subject: ARM: add UEFI stub support This patch adds EFI stub support for the ARM Linux kernel. The EFI stub operates similarly to the x86 and arm64 stubs: it is a shim between the EFI firmware and the normal zImage entry point, and sets up the environment that the zImage is expecting. This includes optionally loading the initrd and device tree from the system partition based on the kernel command line. Signed-off-by: Roy Franz Tested-by: Ryan Harkin Reviewed-by: Matt Fleming Signed-off-by: Ard Biesheuvel --- arch/arm/boot/compressed/Makefile | 4 +- arch/arm/boot/compressed/efi-header.S | 130 +++++++++++++++++++++++++++++++++ arch/arm/boot/compressed/head.S | 54 +++++++++++++- arch/arm/boot/compressed/vmlinux.lds.S | 7 ++ 4 files changed, 192 insertions(+), 3 deletions(-) create mode 100644 arch/arm/boot/compressed/efi-header.S (limited to 'arch/arm/boot') diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile index 3f9a9ebc77c3..4c23a68a0917 100644 --- a/arch/arm/boot/compressed/Makefile +++ b/arch/arm/boot/compressed/Makefile @@ -167,9 +167,11 @@ if [ $(words $(ZRELADDR)) -gt 1 -a "$(CONFIG_AUTO_ZRELADDR)" = "" ]; then \ false; \ fi +efi-obj-$(CONFIG_EFI_STUB) := $(objtree)/drivers/firmware/efi/libstub/lib.a + $(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \ $(addprefix $(obj)/, $(OBJS)) $(lib1funcs) $(ashldi3) \ - $(bswapsdi2) FORCE + $(bswapsdi2) $(efi-obj-y) FORCE @$(check_for_multiple_zreladdr) $(call if_changed,ld) @$(check_for_bad_syms) diff --git a/arch/arm/boot/compressed/efi-header.S b/arch/arm/boot/compressed/efi-header.S new file mode 100644 index 000000000000..9d5dc4fda3c1 --- /dev/null +++ b/arch/arm/boot/compressed/efi-header.S @@ -0,0 +1,130 @@ +/* + * Copyright (C) 2013-2015 Linaro Ltd + * Authors: Roy Franz + * Ard Biesheuvel + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + + .macro __nop +#ifdef CONFIG_EFI_STUB + @ This is almost but not quite a NOP, since it does clobber the + @ condition flags. But it is the best we can do for EFI, since + @ PE/COFF expects the magic string "MZ" at offset 0, while the + @ ARM/Linux boot protocol expects an executable instruction + @ there. + .inst 'M' | ('Z' << 8) | (0x1310 << 16) @ tstne r0, #0x4d000 +#else + mov r0, r0 +#endif + .endm + + .macro __EFI_HEADER +#ifdef CONFIG_EFI_STUB + b __efi_start + + .set start_offset, __efi_start - start + .org start + 0x3c + @ + @ The PE header can be anywhere in the file, but for + @ simplicity we keep it together with the MSDOS header + @ The offset to the PE/COFF header needs to be at offset + @ 0x3C in the MSDOS header. + @ The only 2 fields of the MSDOS header that are used are this + @ PE/COFF offset, and the "MZ" bytes at offset 0x0. + @ + .long pe_header - start @ Offset to the PE header. + +pe_header: + .ascii "PE\0\0" + +coff_header: + .short 0x01c2 @ ARM or Thumb + .short 2 @ nr_sections + .long 0 @ TimeDateStamp + .long 0 @ PointerToSymbolTable + .long 1 @ NumberOfSymbols + .short section_table - optional_header + @ SizeOfOptionalHeader + .short 0x306 @ Characteristics. + @ IMAGE_FILE_32BIT_MACHINE | + @ IMAGE_FILE_DEBUG_STRIPPED | + @ IMAGE_FILE_EXECUTABLE_IMAGE | + @ IMAGE_FILE_LINE_NUMS_STRIPPED + +optional_header: + .short 0x10b @ PE32 format + .byte 0x02 @ MajorLinkerVersion + .byte 0x14 @ MinorLinkerVersion + .long _end - __efi_start @ SizeOfCode + .long 0 @ SizeOfInitializedData + .long 0 @ SizeOfUninitializedData + .long efi_stub_entry - start @ AddressOfEntryPoint + .long start_offset @ BaseOfCode + .long 0 @ data + +extra_header_fields: + .long 0 @ ImageBase + .long 0x200 @ 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 _end - start @ SizeOfImage + .long start_offset @ SizeOfHeaders + .long 0 @ CheckSum + .short 0xa @ Subsystem (EFI application) + .short 0 @ DllCharacteristics + .long 0 @ SizeOfStackReserve + .long 0 @ SizeOfStackCommit + .long 0 @ SizeOfHeapReserve + .long 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: + @ + @ 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\0\0" + .long 0 @ VirtualSize + .long 0 @ VirtualAddress + .long 0 @ SizeOfRawData + .long 0 @ PointerToRawData + .long 0 @ PointerToRelocations + .long 0 @ PointerToLineNumbers + .short 0 @ NumberOfRelocations + .short 0 @ NumberOfLineNumbers + .long 0x42100040 @ Characteristics + + .ascii ".text\0\0\0" + .long _end - __efi_start @ VirtualSize + .long __efi_start @ VirtualAddress + .long _edata - __efi_start @ SizeOfRawData + .long __efi_start @ PointerToRawData + .long 0 @ PointerToRelocations + .long 0 @ PointerToLineNumbers + .short 0 @ NumberOfRelocations + .short 0 @ NumberOfLineNumbers + .long 0xe0500020 @ Characteristics + + .align 9 +__efi_start: +#endif + .endm diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index 06e983f59980..af11c2f8f3b7 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -12,6 +12,8 @@ #include #include +#include "efi-header.S" + AR_CLASS( .arch armv7-a ) M_CLASS( .arch armv7-m ) @@ -126,7 +128,7 @@ start: .type start,#function .rept 7 - mov r0, r0 + __nop .endr ARM( mov r0, r0 ) ARM( b 1f ) @@ -139,7 +141,8 @@ start: .word 0x04030201 @ endianness flag THUMB( .thumb ) -1: +1: __EFI_HEADER + ARM_BE8( setend be ) @ go BE8 if compiled for BE8 AR_CLASS( mrs r9, cpsr ) #ifdef CONFIG_ARM_VIRT_EXT @@ -1353,6 +1356,53 @@ __enter_kernel: reloc_code_end: +#ifdef CONFIG_EFI_STUB + .align 2 +_start: .long start - . + +ENTRY(efi_stub_entry) + @ allocate space on stack for passing current zImage address + @ and for the EFI stub to return of new entry point of + @ zImage, as EFI stub may copy the kernel. Pointer address + @ is passed in r2. r0 and r1 are passed through from the + @ EFI firmware to efi_entry + adr ip, _start + ldr r3, [ip] + add r3, r3, ip + stmfd sp!, {r3, lr} + mov r2, sp @ pass zImage address in r2 + bl efi_entry + + @ Check for error return from EFI stub. r0 has FDT address + @ or error code. + cmn r0, #1 + beq efi_load_fail + + @ Preserve return value of efi_entry() in r4 + mov r4, r0 + bl cache_clean_flush + bl cache_off + + @ Set parameters for booting zImage according to boot protocol + @ put FDT address in r2, it was returned by efi_entry() + @ r1 is the machine type, and r0 needs to be 0 + mov r0, #0 + mov r1, #0xFFFFFFFF + mov r2, r4 + + @ Branch to (possibly) relocated zImage that is in [sp] + ldr lr, [sp] + ldr ip, =start_offset + add lr, lr, ip + mov pc, lr @ no mode switch + +efi_load_fail: + @ Return EFI_LOAD_ERROR to EFI firmware on error. + ldr r0, =0x80000001 + ldmfd sp!, {ip, pc} +ENDPROC(efi_stub_entry) +#endif + .align .section ".stack", "aw", %nobits .L_user_stack: .space 4096 diff --git a/arch/arm/boot/compressed/vmlinux.lds.S b/arch/arm/boot/compressed/vmlinux.lds.S index 2b60b843ac5e..81c493156ce8 100644 --- a/arch/arm/boot/compressed/vmlinux.lds.S +++ b/arch/arm/boot/compressed/vmlinux.lds.S @@ -48,6 +48,13 @@ SECTIONS *(.rodata) *(.rodata.*) } + .data : { + /* + * The EFI stub always executes from RAM, and runs strictly before the + * decompressor, so we can make an exception for its r/w data, and keep it + */ + *(.data.efistub) + } .piggydata : { *(.piggydata) } -- cgit v1.2.3