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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: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lore.kernel.org/r/20220629041207.1670133-1-anshuman.khandual@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Mark Rutland 2022-06-29 09:42:07 +05:30 committed by Will Deacon
parent fbf6ad5efe
commit bdbcd22d49
1 changed files with 3 additions and 8 deletions
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11
arch/arm64/kernel/head.S
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@ -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)