Commit bdbcd22d authored by Mark Rutland's avatar Mark Rutland Committed by Will Deacon
Browse files

arm64: head: remove __PHYS_OFFSET 



It's very easy to confuse __PHYS_OFFSET and PHYS_OFFSET. To clarify
things, let's remove __PHYS_OFFSET and use KERNEL_START directly, with
comments to show that we're using physical address, as we do for other
objects.

At the same time, update the comment regarding the kernel entry address
to mention __pa(KERNEL_START) rather than __pa(PAGE_OFFSET).

There should be no functional change as a result of this patch.

Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: default avatarArd Biesheuvel <ardb@kernel.org>
Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20220629041207.1670133-1-anshuman.khandual@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent fbf6ad5e

arch/arm64/kernel/head.S

+3 −8
Original line number Diff line number Diff line
@@ -37,8 +37,6 @@ 


#include "efi-header.S"



#define __PHYS_OFFSET	KERNEL_START



#if (PAGE_OFFSET & 0x1fffff) != 0

#error PAGE_OFFSET must be at least 2MB aligned

#endif
@@ -51,9 +49,6 @@ 
 *   MMU = off, D-cache = off, I-cache = on or off,

 *   x0 = physical address to the FDT blob.

 *

 * This code is mostly position independent so you call this at

 * __pa(PAGE_OFFSET).

 *

 * Note that the callee-saved registers are used for storing variables

 * that are useful before the MMU is enabled. The allocations are described

 * in the entry routines.
@@ -409,7 +404,7 @@ SYM_FUNC_END(create_kernel_mapping) 
/*

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

 *

 *   x0 = __PHYS_OFFSET

 *   x0 = __pa(KERNEL_START)

 */

SYM_FUNC_START_LOCAL(__primary_switched)

	adr_l	x4, init_task
@@ -793,7 +788,7 @@ SYM_FUNC_START_LOCAL(__primary_switch) 
	adrp	x2, init_idmap_pg_dir

	bl	__enable_mmu

#ifdef CONFIG_RELOCATABLE

	adrp	x23, __PHYS_OFFSET

	adrp	x23, KERNEL_START

	and	x23, x23, MIN_KIMG_ALIGN - 1

#ifdef CONFIG_RANDOMIZE_BASE

	mov	x0, x22
@@ -815,6 +810,6 @@ SYM_FUNC_START_LOCAL(__primary_switch) 
	bl	__relocate_kernel

#endif

	ldr	x8, =__primary_switched

	adrp	x0, __PHYS_OFFSET

	adrp	x0, KERNEL_START		// __pa(KERNEL_START)

	br	x8

SYM_FUNC_END(__primary_switch)