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Commit 17a7d484 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Sami Tolvanen
Browse files

UPSTREAM: arm64: remove __switch_data object from head.S 



This removes the confusing __switch_data object from head.S,
and replaces it with standard PC-relative references to the
various symbols it encapsulates.

Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>

Bug: 31432001
Change-Id: If52281bab37cc229f933e5a7a9da6a0f6867b744
(cherry picked from commit a871d354f795c4960543fb44c9b59af63367d6cf)
Signed-off-by: default avatarSami Tolvanen <samitolvanen@google.com>
parent 731fcbb2

arch/arm64/kernel/head.S

+8 −21
Original line number Diff line number Diff line
@@ -248,7 +248,7 @@ ENTRY(stext) 
	 * On return, the CPU will be ready for the MMU to be turned on and

	 * the TCR will have been set.

	 */

	ldr	x27, __switch_data		// address to jump to after

	ldr	x27, =__mmap_switched		// address to jump to after

						// MMU has been enabled

	adrp	lr, __enable_mmu		// return (PIC) address

	add	lr, lr, #:lo12:__enable_mmu
@@ -415,35 +415,22 @@ __create_page_tables: 
ENDPROC(__create_page_tables)

	.ltorg



	.align	3

	.type	__switch_data, %object

__switch_data:

	.quad	__mmap_switched

	.quad	__bss_start			// x6

	.quad	__bss_stop			// x7

	.quad	__fdt_pointer			// x5

	.quad	memstart_addr			// x6

	.quad	init_thread_union + THREAD_START_SP // sp



/*

 * The following fragment of code is executed with the MMU on in MMU mode, and

 * uses absolute addresses; this is not position independent.

 * The following fragment of code is executed with the MMU enabled.

 */

	.set	initial_sp, init_thread_union + THREAD_START_SP

__mmap_switched:

	adr	x3, __switch_data + 8

	adr_l	x6, __bss_start

	adr_l	x7, __bss_stop



	ldp	x6, x7, [x3], #16

1:	cmp	x6, x7

	b.hs	2f

	str	xzr, [x6], #8			// Clear BSS

	b	1b

2:

	ldr	x5, [x3], #8

	ldr	x6, [x3], #8

	ldr	x16, [x3]

	mov	sp, x16

	str	x21, [x5]			// Save FDT pointer

	str	x24, [x6]			// Save PHYS_OFFSET

	adr_l	sp, initial_sp, x4

	str_l	x21, __fdt_pointer, x5		// Save FDT pointer

	str_l	x24, memstart_addr, x6		// Save PHYS_OFFSET

	mov	x29, #0

	b	start_kernel

ENDPROC(__mmap_switched)