[04/30] ARM: head-common.S: use PC-relative insn sequence for idmap creation
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Message ID 20170814125411.22604-5-ard.biesheuvel@linaro.org
State New
Headers show

Commit Message

Ard Biesheuvel Aug. 14, 2017, 12:53 p.m. UTC
Replace the open coded PC relative offset calculations involving
__turn_mmu_on and __turn_mmu_on_end with a pair of adr_l invocations.
This ensures these quantities are invariant under runtime relocation.

Cc: Russell King <linux@armlinux.org.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm/kernel/head.S | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

Patch
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diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 04286fd9e09c..0a98aec0e39d 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -227,11 +227,8 @@  __create_page_tables:
 	 * Create identity mapping to cater for __enable_mmu.
 	 * This identity mapping will be removed by paging_init().
 	 */
-	adr	r0, __turn_mmu_on_loc
-	ldmia	r0, {r3, r5, r6}
-	sub	r0, r0, r3			@ virt->phys offset
-	add	r5, r5, r0			@ phys __turn_mmu_on
-	add	r6, r6, r0			@ phys __turn_mmu_on_end
+	adr_l	r5, __turn_mmu_on		@ _pa(__turn_mmu_on)
+	adr_l	r6, __turn_mmu_on_end		@ _pa(__turn_mmu_on_end)
 	mov	r5, r5, lsr #SECTION_SHIFT
 	mov	r6, r6, lsr #SECTION_SHIFT
 
@@ -354,11 +351,6 @@  __create_page_tables:
 	ret	lr
 ENDPROC(__create_page_tables)
 	.ltorg
-	.align
-__turn_mmu_on_loc:
-	.long	.
-	.long	__turn_mmu_on
-	.long	__turn_mmu_on_end
 
 #if defined(CONFIG_SMP)
 	.text