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ARM: make the physical-relative calculation more obvious

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The physical-relative calculation between the XIP text and data sections
introduced by the previous patch was far from obvious. Let's simplify it
by turning it into a macro which takes the two (virtual) addresses.

This allows us to arrange the calculation in a more obvious manner - we
can make it two sub-expressions which calculate the physical address for
each symbol, and then takes the difference of those physical addresses.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2016-02-16 17:33:56 +00:00
parent d781145549
commit 8ff97fa313
2 changed files with 12 additions and 5 deletions
arch/arm
include/asm
memory.h
mm
proc-v7.S

15
arch/arm/include/asm/memory.h
View File

@ -135,11 +135,18 @@
#define PLAT_PHYS_OFFSET UL(CONFIG_PHYS_OFFSET)
#ifdef CONFIG_XIP_KERNEL
#define PHYS_OFFSET_FIXUP \
( XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) - PAGE_OFFSET + \
PLAT_PHYS_OFFSET - CONFIG_XIP_PHYS_ADDR )
/*
* When referencing data in RAM from the XIP region in a relative manner
* with the MMU off, we need the relative offset between the two physical
* addresses. The macro below achieves this, which is:
* __pa(v_data) - __xip_pa(v_text)
*/
#define PHYS_RELATIVE(v_data, v_text) \
(((v_data) - PAGE_OFFSET + PLAT_PHYS_OFFSET) - \
((v_text) - XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR) + \
CONFIG_XIP_PHYS_ADDR))
#else
#define PHYS_OFFSET_FIXUP 0
#define PHYS_RELATIVE(v_data, v_text) ((v_data) - (v_text))
#endif
#ifndef __ASSEMBLY__

2
arch/arm/mm/proc-v7.S
View File

@ -487,7 +487,7 @@ __errata_finish:
.align 2
__v7_setup_stack_ptr:
.word __v7_setup_stack - . + PHYS_OFFSET_FIXUP
.word PHYS_RELATIVE(__v7_setup_stack, .)
ENDPROC(__v7_setup)
.bss