ARM: p2v: move patching code to separate assembler source file

Move the phys2virt patching code into a separate .S file before doing
some work on it.

Suggested-by: Nicolas Pitre <nico@fluxnic.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Ard Biesheuvel 2020-09-20 17:51:55 +02:00
parent 22f2d23098
commit eae78e1a97
3 changed files with 152 additions and 138 deletions

View file

@ -92,6 +92,7 @@ obj-$(CONFIG_PARAVIRT) += paravirt.o
head-y := head$(MMUEXT).o
obj-$(CONFIG_DEBUG_LL) += debug.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_ARM_PATCH_PHYS_VIRT) += phys2virt.o
# This is executed very early using a temporary stack when no memory allocator
# nor global data is available. Everything has to be allocated on the stack.

View file

@ -586,142 +586,4 @@ ENTRY(fixup_smp)
ldmfd sp!, {r4 - r6, pc}
ENDPROC(fixup_smp)
#ifdef __ARMEB__
#define LOW_OFFSET 0x4
#define HIGH_OFFSET 0x0
#else
#define LOW_OFFSET 0x0
#define HIGH_OFFSET 0x4
#endif
#ifdef CONFIG_ARM_PATCH_PHYS_VIRT
/* __fixup_pv_table - patch the stub instructions with the delta between
* PHYS_OFFSET and PAGE_OFFSET, which is assumed to be 16MiB aligned and
* can be expressed by an immediate shifter operand. The stub instruction
* has a form of '(add|sub) rd, rn, #imm'.
*/
__HEAD
__fixup_pv_table:
adr r0, 1f
ldmia r0, {r3-r7}
mvn ip, #0
subs r3, r0, r3 @ PHYS_OFFSET - PAGE_OFFSET
add r4, r4, r3 @ adjust table start address
add r5, r5, r3 @ adjust table end address
add r6, r6, r3 @ adjust __pv_phys_pfn_offset address
add r7, r7, r3 @ adjust __pv_offset address
mov r0, r8, lsr #PAGE_SHIFT @ convert to PFN
str r0, [r6] @ save computed PHYS_OFFSET to __pv_phys_pfn_offset
strcc ip, [r7, #HIGH_OFFSET] @ save to __pv_offset high bits
mov r6, r3, lsr #24 @ constant for add/sub instructions
teq r3, r6, lsl #24 @ must be 16MiB aligned
THUMB( it ne @ cross section branch )
bne __error
str r3, [r7, #LOW_OFFSET] @ save to __pv_offset low bits
b __fixup_a_pv_table
ENDPROC(__fixup_pv_table)
.align
1: .long .
.long __pv_table_begin
.long __pv_table_end
2: .long __pv_phys_pfn_offset
.long __pv_offset
.text
__fixup_a_pv_table:
adr r0, 3f
ldr r6, [r0]
add r6, r6, r3
ldr r0, [r6, #HIGH_OFFSET] @ pv_offset high word
ldr r6, [r6, #LOW_OFFSET] @ pv_offset low word
mov r6, r6, lsr #24
cmn r0, #1
#ifdef CONFIG_THUMB2_KERNEL
moveq r0, #0x200000 @ set bit 21, mov to mvn instruction
lsls r6, #24
beq 2f
clz r7, r6
lsr r6, #24
lsl r6, r7
bic r6, #0x0080
lsrs r7, #1
orrcs r6, #0x0080
orr r6, r6, r7, lsl #12
orr r6, #0x4000
b 2f
1: add r7, r3
ldrh ip, [r7, #2]
ARM_BE8(rev16 ip, ip)
tst ip, #0x4000
and ip, #0x8f00
orrne ip, r6 @ mask in offset bits 31-24
orreq ip, r0 @ mask in offset bits 7-0
ARM_BE8(rev16 ip, ip)
strh ip, [r7, #2]
bne 2f
ldrh ip, [r7]
ARM_BE8(rev16 ip, ip)
bic ip, #0x20
orr ip, ip, r0, lsr #16
ARM_BE8(rev16 ip, ip)
strh ip, [r7]
2: cmp r4, r5
ldrcc r7, [r4], #4 @ use branch for delay slot
bcc 1b
bx lr
#else
moveq r0, #0x400000 @ set bit 22, mov to mvn instruction
b 2f
1: ldr ip, [r7, r3]
#ifdef CONFIG_CPU_ENDIAN_BE8
@ in BE8, we load data in BE, but instructions still in LE
bic ip, ip, #0xff000000
tst ip, #0x000f0000 @ check the rotation field
orrne ip, ip, r6, lsl #24 @ mask in offset bits 31-24
biceq ip, ip, #0x00004000 @ clear bit 22
orreq ip, ip, r0, ror #8 @ mask in offset bits 7-0
#else
bic ip, ip, #0x000000ff
tst ip, #0xf00 @ check the rotation field
orrne ip, ip, r6 @ mask in offset bits 31-24
biceq ip, ip, #0x400000 @ clear bit 22
orreq ip, ip, r0 @ mask in offset bits 7-0
#endif
str ip, [r7, r3]
2: cmp r4, r5
ldrcc r7, [r4], #4 @ use branch for delay slot
bcc 1b
ret lr
#endif
ENDPROC(__fixup_a_pv_table)
.align
3: .long __pv_offset
ENTRY(fixup_pv_table)
stmfd sp!, {r4 - r7, lr}
mov r3, #0 @ no offset
mov r4, r0 @ r0 = table start
add r5, r0, r1 @ r1 = table size
bl __fixup_a_pv_table
ldmfd sp!, {r4 - r7, pc}
ENDPROC(fixup_pv_table)
.data
.align 2
.globl __pv_phys_pfn_offset
.type __pv_phys_pfn_offset, %object
__pv_phys_pfn_offset:
.word 0
.size __pv_phys_pfn_offset, . -__pv_phys_pfn_offset
.globl __pv_offset
.type __pv_offset, %object
__pv_offset:
.quad 0
.size __pv_offset, . -__pv_offset
#endif
#include "head-common.S"

151
arch/arm/kernel/phys2virt.S Normal file
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@ -0,0 +1,151 @@
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 1994-2002 Russell King
* Copyright (c) 2003 ARM Limited
* All Rights Reserved
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/page.h>
#ifdef __ARMEB__
#define LOW_OFFSET 0x4
#define HIGH_OFFSET 0x0
#else
#define LOW_OFFSET 0x0
#define HIGH_OFFSET 0x4
#endif
/*
* __fixup_pv_table - patch the stub instructions with the delta between
* PHYS_OFFSET and PAGE_OFFSET, which is assumed to be
* 16MiB aligned.
*
* Called from head.S, which expects the following registers to be preserved:
* r1 = machine no, r2 = atags or dtb,
* r8 = phys_offset, r9 = cpuid, r10 = procinfo
*/
__HEAD
ENTRY(__fixup_pv_table)
adr r0, 1f
ldmia r0, {r3-r7}
mvn ip, #0
subs r3, r0, r3 @ PHYS_OFFSET - PAGE_OFFSET
add r4, r4, r3 @ adjust table start address
add r5, r5, r3 @ adjust table end address
add r6, r6, r3 @ adjust __pv_phys_pfn_offset address
add r7, r7, r3 @ adjust __pv_offset address
mov r0, r8, lsr #PAGE_SHIFT @ convert to PFN
str r0, [r6] @ save computed PHYS_OFFSET to __pv_phys_pfn_offset
strcc ip, [r7, #HIGH_OFFSET] @ save to __pv_offset high bits
mov r6, r3, lsr #24 @ constant for add/sub instructions
teq r3, r6, lsl #24 @ must be 16MiB aligned
bne 0f
str r3, [r7, #LOW_OFFSET] @ save to __pv_offset low bits
b __fixup_a_pv_table
0: mov r0, r0 @ deadloop on error
b 0b
ENDPROC(__fixup_pv_table)
.align
1: .long .
.long __pv_table_begin
.long __pv_table_end
2: .long __pv_phys_pfn_offset
.long __pv_offset
.text
__fixup_a_pv_table:
adr r0, 3f
ldr r6, [r0]
add r6, r6, r3
ldr r0, [r6, #HIGH_OFFSET] @ pv_offset high word
ldr r6, [r6, #LOW_OFFSET] @ pv_offset low word
mov r6, r6, lsr #24
cmn r0, #1
#ifdef CONFIG_THUMB2_KERNEL
moveq r0, #0x200000 @ set bit 21, mov to mvn instruction
lsls r6, #24
beq 2f
clz r7, r6
lsr r6, #24
lsl r6, r7
bic r6, #0x0080
lsrs r7, #1
orrcs r6, #0x0080
orr r6, r6, r7, lsl #12
orr r6, #0x4000
b 2f
1: add r7, r3
ldrh ip, [r7, #2]
ARM_BE8(rev16 ip, ip)
tst ip, #0x4000
and ip, #0x8f00
orrne ip, r6 @ mask in offset bits 31-24
orreq ip, r0 @ mask in offset bits 7-0
ARM_BE8(rev16 ip, ip)
strh ip, [r7, #2]
bne 2f
ldrh ip, [r7]
ARM_BE8(rev16 ip, ip)
bic ip, #0x20
orr ip, ip, r0, lsr #16
ARM_BE8(rev16 ip, ip)
strh ip, [r7]
2: cmp r4, r5
ldrcc r7, [r4], #4 @ use branch for delay slot
bcc 1b
bx lr
#else
moveq r0, #0x400000 @ set bit 22, mov to mvn instruction
b 2f
1: ldr ip, [r7, r3]
#ifdef CONFIG_CPU_ENDIAN_BE8
@ in BE8, we load data in BE, but instructions still in LE
bic ip, ip, #0xff000000
tst ip, #0x000f0000 @ check the rotation field
orrne ip, ip, r6, lsl #24 @ mask in offset bits 31-24
biceq ip, ip, #0x00004000 @ clear bit 22
orreq ip, ip, r0, ror #8 @ mask in offset bits 7-0
#else
bic ip, ip, #0x000000ff
tst ip, #0xf00 @ check the rotation field
orrne ip, ip, r6 @ mask in offset bits 31-24
biceq ip, ip, #0x400000 @ clear bit 22
orreq ip, ip, r0 @ mask in offset bits 7-0
#endif
str ip, [r7, r3]
2: cmp r4, r5
ldrcc r7, [r4], #4 @ use branch for delay slot
bcc 1b
ret lr
#endif
ENDPROC(__fixup_a_pv_table)
.align
3: .long __pv_offset
ENTRY(fixup_pv_table)
stmfd sp!, {r4 - r7, lr}
mov r3, #0 @ no offset
mov r4, r0 @ r0 = table start
add r5, r0, r1 @ r1 = table size
bl __fixup_a_pv_table
ldmfd sp!, {r4 - r7, pc}
ENDPROC(fixup_pv_table)
.data
.align 2
.globl __pv_phys_pfn_offset
.type __pv_phys_pfn_offset, %object
__pv_phys_pfn_offset:
.word 0
.size __pv_phys_pfn_offset, . -__pv_phys_pfn_offset
.globl __pv_offset
.type __pv_offset, %object
__pv_offset:
.quad 0
.size __pv_offset, . -__pv_offset