Merge tag 'arm-adrl-replacement-for-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux into devel-stable

Tidy up open coded relative references in asm

Use the newly introduced adr_l/ldr_l/str_l/mov_l assembler macros to
replace open coded VA-to-PA arithmetic in various places in the code. This
avoids the use of literals on v7+ CPUs, reduces the footprint of the code
in most cases, and generally makes the code easier to follow.

Series was posted here, and reviewed by Nicolas Pitre:
https://lore.kernel.org/linux-arm-kernel/20200914095706.3985-1-ardb@kernel.org/

1 files changed, 15 insertions, 48 deletions

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 7e3f36809011..ae0b08b47f52 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -103,10 +103,8 @@ ENTRY(stext)
 #endif
 
 #ifndef CONFIG_XIP_KERNEL
-	adr	r3, 2f
-	ldmia	r3, {r4, r8}
-	sub	r4, r3, r4			@ (PHYS_OFFSET - PAGE_OFFSET)
-	add	r8, r8, r4			@ PHYS_OFFSET
+	adr_l	r8, _text			@ __pa(_text)
+	sub	r8, r8, #TEXT_OFFSET		@ PHYS_OFFSET
 #else
 	ldr	r8, =PLAT_PHYS_OFFSET		@ always constant in this case
 #endif
@@ -158,10 +156,6 @@ ENTRY(stext)
 1:	b	__enable_mmu
 ENDPROC(stext)
 	.ltorg
-#ifndef CONFIG_XIP_KERNEL
-2:	.long	.
-	.long	PAGE_OFFSET
-#endif
 
 /*
  * Setup the initial page tables.  We only setup the barest
@@ -224,11 +218,8 @@ __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
 
@@ -351,11 +342,6 @@ __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
@@ -391,10 +377,8 @@ ENTRY(secondary_startup)
 	/*
 	 * Use the page tables supplied from  __cpu_up.
 	 */
-	adr	r4, __secondary_data
-	ldmia	r4, {r5, r7, r12}		@ address to jump to after
-	sub	lr, r4, r5			@ mmu has been enabled
-	add	r3, r7, lr
+	adr_l	r3, secondary_data
+	mov_l	r12, __secondary_switched
 	ldrd	r4, r5, [r3, #0]		@ get secondary_data.pgdir
 ARM_BE8(eor	r4, r4, r5)			@ Swap r5 and r4 in BE:
 ARM_BE8(eor	r5, r4, r5)			@ it can be done in 3 steps
@@ -409,22 +393,13 @@ ARM_BE8(eor	r4, r4, r5)			@ without using a temp reg.
 ENDPROC(secondary_startup)
 ENDPROC(secondary_startup_arm)
 
-	/*
-	 * r6  = &secondary_data
-	 */
 ENTRY(__secondary_switched)
-	ldr	sp, [r7, #12]			@ get secondary_data.stack
+	ldr_l	r7, secondary_data + 12		@ get secondary_data.stack
+	mov	sp, r7
 	mov	fp, #0
 	b	secondary_start_kernel
 ENDPROC(__secondary_switched)
 
-	.align
-
-	.type	__secondary_data, %object
-__secondary_data:
-	.long	.
-	.long	secondary_data
-	.long	__secondary_switched
 #endif /* defined(CONFIG_SMP) */
 
 
@@ -539,19 +514,11 @@ ARM_BE8(rev	r0, r0)			@ byteswap if big endian
 	retne	lr
 
 __fixup_smp_on_up:
-	adr	r0, 1f
-	ldmia	r0, {r3 - r5}
-	sub	r3, r0, r3
-	add	r4, r4, r3
-	add	r5, r5, r3
+	adr_l	r4, __smpalt_begin
+	adr_l	r5, __smpalt_end
 	b	__do_fixup_smp_on_up
 ENDPROC(__fixup_smp)
 
-	.align
-1:	.word	.
-	.word	__smpalt_begin
-	.word	__smpalt_end
-
 	.pushsection .data
 	.align	2
 	.globl	smp_on_up
@@ -565,14 +532,15 @@ smp_on_up:
 __do_fixup_smp_on_up:
 	cmp	r4, r5
 	reths	lr
-	ldmia	r4!, {r0, r6}
- ARM(	str	r6, [r0, r3]	)
- THUMB(	add	r0, r0, r3	)
+	ldmia	r4, {r0, r6}
+ ARM(	str	r6, [r0, r4]	)
+ THUMB(	add	r0, r0, r4	)
+	add	r4, r4, #8
 #ifdef __ARMEB__
  THUMB(	mov	r6, r6, ror #16	)	@ Convert word order for big-endian.
 #endif
  THUMB(	strh	r6, [r0], #2	)	@ For Thumb-2, store as two halfwords
- THUMB(	mov	r6, r6, lsr #16	)	@ to be robust against misaligned r3.
+ THUMB(	mov	r6, r6, lsr #16	)	@ to be robust against misaligned r0.
  THUMB(	strh	r6, [r0]	)
 	b	__do_fixup_smp_on_up
 ENDPROC(__do_fixup_smp_on_up)
@@ -581,7 +549,6 @@ ENTRY(fixup_smp)
 	stmfd	sp!, {r4 - r6, lr}
 	mov	r4, r0
 	add	r5, r0, r1
-	mov	r3, #0
 	bl	__do_fixup_smp_on_up
 	ldmfd	sp!, {r4 - r6, pc}
 ENDPROC(fixup_smp)