Commit 546c8c44 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon
Browse files

arm64: move early boot code to the .init segment 



Apart from the arm64/linux and EFI header data structures, there is nothing
in the .head.text section that must reside at the beginning of the Image.
So let's move it to the .init section where it belongs.

Note that this involves some minor tweaking of the EFI header, primarily
because the address of 'stext' no longer coincides with the start of the
.text section. It also requires a couple of relocated symbol references
to be slightly rewritten or their definition moved to the linker script.

Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 2c09ec06

arch/arm64/kernel/efi-entry.S

+1 −1
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ ENTRY(entry) 
	 */

	mov	x20, x0		// DTB address

	ldr	x0, [sp, #16]	// relocated _text address

	movz	x21, #:abs_g0:stext_offset

	ldr	w21, =stext_offset

	add	x21, x0, x21



	/*

arch/arm64/kernel/head.S

+15 −17
Original line number Diff line number Diff line
@@ -102,8 +102,6 @@ _head: 
#endif



#ifdef CONFIG_EFI

	.globl	__efistub_stext_offset

	.set	__efistub_stext_offset, stext - _head

	.align 3

pe_header:

	.ascii	"PE"
@@ -123,11 +121,11 @@ optional_header: 
	.short	0x20b				// PE32+ format

	.byte	0x02				// MajorLinkerVersion

	.byte	0x14				// MinorLinkerVersion

	.long	_end - stext			// SizeOfCode

	.long	_end - efi_header_end		// SizeOfCode

	.long	0				// SizeOfInitializedData

	.long	0				// SizeOfUninitializedData

	.long	__efistub_entry - _head		// AddressOfEntryPoint

	.long	__efistub_stext_offset		// BaseOfCode

	.long	efi_header_end - _head		// BaseOfCode



extra_header_fields:

	.quad	0				// ImageBase
@@ -144,7 +142,7 @@ extra_header_fields: 
	.long	_end - _head			// SizeOfImage



	// Everything before the kernel image is considered part of the header

	.long	__efistub_stext_offset		// SizeOfHeaders

	.long	efi_header_end - _head		// SizeOfHeaders

	.long	0				// CheckSum

	.short	0xa				// Subsystem (EFI application)

	.short	0				// DllCharacteristics
@@ -188,10 +186,10 @@ section_table: 
	.byte	0

	.byte	0

	.byte	0        		// end of 0 padding of section name

	.long	_end - stext		// VirtualSize

	.long	__efistub_stext_offset	// VirtualAddress

	.long	_edata - stext		// SizeOfRawData

	.long	__efistub_stext_offset	// PointerToRawData

	.long	_end - efi_header_end	// VirtualSize

	.long	efi_header_end - _head	// VirtualAddress

	.long	_edata - efi_header_end	// SizeOfRawData

	.long	efi_header_end - _head	// PointerToRawData



	.long	0		// PointerToRelocations (0 for executables)

	.long	0		// PointerToLineNumbers (0 for executables)
@@ -200,15 +198,18 @@ section_table: 
	.long	0xe0500020	// Characteristics (section flags)



	/*

	 * EFI will load stext onwards at the 4k section alignment

	 * EFI will load .text onwards at the 4k section alignment

	 * described in the PE/COFF header. To ensure that instruction

	 * sequences using an adrp and a :lo12: immediate will function

	 * correctly at this alignment, we must ensure that stext is

	 * correctly at this alignment, we must ensure that .text is

	 * placed at a 4k boundary in the Image to begin with.

	 */

	.align 12

efi_header_end:

#endif



	__INIT



ENTRY(stext)

	bl	preserve_boot_args

	bl	el2_setup			// Drop to EL1, w20=cpu_boot_mode
@@ -223,12 +224,12 @@ ENTRY(stext) 
	 * the TCR will have been set.

	 */

	ldr	x27, 0f				// address to jump to after

						// MMU has been enabled

	neg	x27, x27			// MMU has been enabled

	adr_l	lr, __enable_mmu		// return (PIC) address

	b	__cpu_setup			// initialise processor

ENDPROC(stext)

	.align	3

0:	.quad	__mmap_switched - (_head - TEXT_OFFSET) + KIMAGE_VADDR

0:	.quad	(_text - TEXT_OFFSET) - __mmap_switched - KIMAGE_VADDR



/*

 * Preserve the arguments passed by the bootloader in x0 .. x3
@@ -397,7 +398,7 @@ __create_page_tables: 
	ldr	x5, =KIMAGE_VADDR

	add	x5, x5, x23			// add KASLR displacement

	create_pgd_entry x0, x5, x3, x6

	ldr	w6, kernel_img_size

	ldr	w6, =kernel_img_size

	add	x6, x6, x5

	mov	x3, x24				// phys offset

	create_block_map x0, x7, x3, x5, x6
@@ -414,9 +415,6 @@ __create_page_tables: 


	ret	x28

ENDPROC(__create_page_tables)



kernel_img_size:

	.long	_end - (_head - TEXT_OFFSET)

	.ltorg



/*

arch/arm64/kernel/image.h

+4 −0
Original line number Diff line number Diff line
@@ -71,8 +71,12 @@ 
	DEFINE_IMAGE_LE64(_kernel_offset_le, TEXT_OFFSET);	\

	DEFINE_IMAGE_LE64(_kernel_flags_le, __HEAD_FLAGS);



kernel_img_size = _end - (_text - TEXT_OFFSET);



#ifdef CONFIG_EFI



__efistub_stext_offset = stext - _text;



/*

 * Prevent the symbol aliases below from being emitted into the kallsyms

 * table, by forcing them to be absolute symbols (which are conveniently

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