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linux/arch/arm/lib/uaccess.S
Russell King 080fc66fb5 ARM: Bring back ARMv3 IO and user access code 
This partially reverts 357c9c1f07
(ARM: Remove support for ARMv3 ARM610 and ARM710 CPUs).

Although we only support StrongARM on the RiscPC, we need to keep the
ARMv3 user access code for this platform because the bus does not
understand half-word load/stores.

Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-08-13 11:44:13 +01:00

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14 KiB
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/*
* linux/arch/arm/lib/uaccess.S
*
* Copyright (C) 1995, 1996,1997,1998 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* Routines to block copy data to/from user memory
* These are highly optimised both for the 4k page size
* and for various alignments.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/errno.h>
#include <asm/domain.h>
.text
#define PAGE_SHIFT 12
/* Prototype: int __copy_to_user(void *to, const char *from, size_t n)
* Purpose : copy a block to user memory from kernel memory
* Params : to - user memory
* : from - kernel memory
* : n - number of bytes to copy
* Returns : Number of bytes NOT copied.
*/
.Lc2u_dest_not_aligned:
rsb ip, ip, #4
cmp ip, #2
ldrb r3, [r1], #1
USER( TUSER( strb) r3, [r0], #1) @ May fault
ldrgeb r3, [r1], #1
USER( TUSER( strgeb) r3, [r0], #1) @ May fault
ldrgtb r3, [r1], #1
USER( TUSER( strgtb) r3, [r0], #1) @ May fault
sub r2, r2, ip
b .Lc2u_dest_aligned
ENTRY(__copy_to_user)
stmfd sp!, {r2, r4 - r7, lr}
cmp r2, #4
blt .Lc2u_not_enough
ands ip, r0, #3
bne .Lc2u_dest_not_aligned
.Lc2u_dest_aligned:
ands ip, r1, #3
bne .Lc2u_src_not_aligned
/*
* Seeing as there has to be at least 8 bytes to copy, we can
* copy one word, and force a user-mode page fault...
*/
.Lc2u_0fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lc2u_0nowords
ldr r3, [r1], #4
USER( TUSER( str) r3, [r0], #4) @ May fault
mov ip, r0, lsl #32 - PAGE_SHIFT @ On each page, use a ld/st??t instruction
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
beq .Lc2u_0fupi
/*
* ip = max no. of bytes to copy before needing another "strt" insn
*/
cmp r2, ip
movlt ip, r2
sub r2, r2, ip
subs ip, ip, #32
blt .Lc2u_0rem8lp
.Lc2u_0cpy8lp: ldmia r1!, {r3 - r6}
stmia r0!, {r3 - r6} @ Shouldnt fault
ldmia r1!, {r3 - r6}
subs ip, ip, #32
stmia r0!, {r3 - r6} @ Shouldnt fault
bpl .Lc2u_0cpy8lp
.Lc2u_0rem8lp: cmn ip, #16
ldmgeia r1!, {r3 - r6}
stmgeia r0!, {r3 - r6} @ Shouldnt fault
tst ip, #8
ldmneia r1!, {r3 - r4}
stmneia r0!, {r3 - r4} @ Shouldnt fault
tst ip, #4
ldrne r3, [r1], #4
TUSER( strne) r3, [r0], #4 @ Shouldnt fault
ands ip, ip, #3
beq .Lc2u_0fupi
.Lc2u_0nowords: teq ip, #0
beq .Lc2u_finished
.Lc2u_nowords: cmp ip, #2
ldrb r3, [r1], #1
USER( TUSER( strb) r3, [r0], #1) @ May fault
ldrgeb r3, [r1], #1
USER( TUSER( strgeb) r3, [r0], #1) @ May fault
ldrgtb r3, [r1], #1
USER( TUSER( strgtb) r3, [r0], #1) @ May fault
b .Lc2u_finished
.Lc2u_not_enough:
movs ip, r2
bne .Lc2u_nowords
.Lc2u_finished: mov r0, #0
ldmfd sp!, {r2, r4 - r7, pc}
.Lc2u_src_not_aligned:
bic r1, r1, #3
ldr r7, [r1], #4
cmp ip, #2
bgt .Lc2u_3fupi
beq .Lc2u_2fupi
.Lc2u_1fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lc2u_1nowords
mov r3, r7, pull #8
ldr r7, [r1], #4
orr r3, r3, r7, push #24
USER( TUSER( str) r3, [r0], #4) @ May fault
mov ip, r0, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
beq .Lc2u_1fupi
cmp r2, ip
movlt ip, r2
sub r2, r2, ip
subs ip, ip, #16
blt .Lc2u_1rem8lp
.Lc2u_1cpy8lp: mov r3, r7, pull #8
ldmia r1!, {r4 - r7}
subs ip, ip, #16
orr r3, r3, r4, push #24
mov r4, r4, pull #8
orr r4, r4, r5, push #24
mov r5, r5, pull #8
orr r5, r5, r6, push #24
mov r6, r6, pull #8
orr r6, r6, r7, push #24
stmia r0!, {r3 - r6} @ Shouldnt fault
bpl .Lc2u_1cpy8lp
.Lc2u_1rem8lp: tst ip, #8
movne r3, r7, pull #8
ldmneia r1!, {r4, r7}
orrne r3, r3, r4, push #24
movne r4, r4, pull #8
orrne r4, r4, r7, push #24
stmneia r0!, {r3 - r4} @ Shouldnt fault
tst ip, #4
movne r3, r7, pull #8
ldrne r7, [r1], #4
orrne r3, r3, r7, push #24
TUSER( strne) r3, [r0], #4 @ Shouldnt fault
ands ip, ip, #3
beq .Lc2u_1fupi
.Lc2u_1nowords: mov r3, r7, get_byte_1
teq ip, #0
beq .Lc2u_finished
cmp ip, #2
USER( TUSER( strb) r3, [r0], #1) @ May fault
movge r3, r7, get_byte_2
USER( TUSER( strgeb) r3, [r0], #1) @ May fault
movgt r3, r7, get_byte_3
USER( TUSER( strgtb) r3, [r0], #1) @ May fault
b .Lc2u_finished
.Lc2u_2fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lc2u_2nowords
mov r3, r7, pull #16
ldr r7, [r1], #4
orr r3, r3, r7, push #16
USER( TUSER( str) r3, [r0], #4) @ May fault
mov ip, r0, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
beq .Lc2u_2fupi
cmp r2, ip
movlt ip, r2
sub r2, r2, ip
subs ip, ip, #16
blt .Lc2u_2rem8lp
.Lc2u_2cpy8lp: mov r3, r7, pull #16
ldmia r1!, {r4 - r7}
subs ip, ip, #16
orr r3, r3, r4, push #16
mov r4, r4, pull #16
orr r4, r4, r5, push #16
mov r5, r5, pull #16
orr r5, r5, r6, push #16
mov r6, r6, pull #16
orr r6, r6, r7, push #16
stmia r0!, {r3 - r6} @ Shouldnt fault
bpl .Lc2u_2cpy8lp
.Lc2u_2rem8lp: tst ip, #8
movne r3, r7, pull #16
ldmneia r1!, {r4, r7}
orrne r3, r3, r4, push #16
movne r4, r4, pull #16
orrne r4, r4, r7, push #16
stmneia r0!, {r3 - r4} @ Shouldnt fault
tst ip, #4
movne r3, r7, pull #16
ldrne r7, [r1], #4
orrne r3, r3, r7, push #16
TUSER( strne) r3, [r0], #4 @ Shouldnt fault
ands ip, ip, #3
beq .Lc2u_2fupi
.Lc2u_2nowords: mov r3, r7, get_byte_2
teq ip, #0
beq .Lc2u_finished
cmp ip, #2
USER( TUSER( strb) r3, [r0], #1) @ May fault
movge r3, r7, get_byte_3
USER( TUSER( strgeb) r3, [r0], #1) @ May fault
ldrgtb r3, [r1], #0
USER( TUSER( strgtb) r3, [r0], #1) @ May fault
b .Lc2u_finished
.Lc2u_3fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lc2u_3nowords
mov r3, r7, pull #24
ldr r7, [r1], #4
orr r3, r3, r7, push #8
USER( TUSER( str) r3, [r0], #4) @ May fault
mov ip, r0, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
beq .Lc2u_3fupi
cmp r2, ip
movlt ip, r2
sub r2, r2, ip
subs ip, ip, #16
blt .Lc2u_3rem8lp
.Lc2u_3cpy8lp: mov r3, r7, pull #24
ldmia r1!, {r4 - r7}
subs ip, ip, #16
orr r3, r3, r4, push #8
mov r4, r4, pull #24
orr r4, r4, r5, push #8
mov r5, r5, pull #24
orr r5, r5, r6, push #8
mov r6, r6, pull #24
orr r6, r6, r7, push #8
stmia r0!, {r3 - r6} @ Shouldnt fault
bpl .Lc2u_3cpy8lp
.Lc2u_3rem8lp: tst ip, #8
movne r3, r7, pull #24
ldmneia r1!, {r4, r7}
orrne r3, r3, r4, push #8
movne r4, r4, pull #24
orrne r4, r4, r7, push #8
stmneia r0!, {r3 - r4} @ Shouldnt fault
tst ip, #4
movne r3, r7, pull #24
ldrne r7, [r1], #4
orrne r3, r3, r7, push #8
TUSER( strne) r3, [r0], #4 @ Shouldnt fault
ands ip, ip, #3
beq .Lc2u_3fupi
.Lc2u_3nowords: mov r3, r7, get_byte_3
teq ip, #0
beq .Lc2u_finished
cmp ip, #2
USER( TUSER( strb) r3, [r0], #1) @ May fault
ldrgeb r3, [r1], #1
USER( TUSER( strgeb) r3, [r0], #1) @ May fault
ldrgtb r3, [r1], #0
USER( TUSER( strgtb) r3, [r0], #1) @ May fault
b .Lc2u_finished
ENDPROC(__copy_to_user)
.pushsection .fixup,"ax"
.align 0
9001: ldmfd sp!, {r0, r4 - r7, pc}
.popsection
/* Prototype: unsigned long __copy_from_user(void *to,const void *from,unsigned long n);
* Purpose : copy a block from user memory to kernel memory
* Params : to - kernel memory
* : from - user memory
* : n - number of bytes to copy
* Returns : Number of bytes NOT copied.
*/
.Lcfu_dest_not_aligned:
rsb ip, ip, #4
cmp ip, #2
USER( TUSER( ldrb) r3, [r1], #1) @ May fault
strb r3, [r0], #1
USER( TUSER( ldrgeb) r3, [r1], #1) @ May fault
strgeb r3, [r0], #1
USER( TUSER( ldrgtb) r3, [r1], #1) @ May fault
strgtb r3, [r0], #1
sub r2, r2, ip
b .Lcfu_dest_aligned
ENTRY(__copy_from_user)
stmfd sp!, {r0, r2, r4 - r7, lr}
cmp r2, #4
blt .Lcfu_not_enough
ands ip, r0, #3
bne .Lcfu_dest_not_aligned
.Lcfu_dest_aligned:
ands ip, r1, #3
bne .Lcfu_src_not_aligned
/*
* Seeing as there has to be at least 8 bytes to copy, we can
* copy one word, and force a user-mode page fault...
*/
.Lcfu_0fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lcfu_0nowords
USER( TUSER( ldr) r3, [r1], #4)
str r3, [r0], #4
mov ip, r1, lsl #32 - PAGE_SHIFT @ On each page, use a ld/st??t instruction
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
beq .Lcfu_0fupi
/*
* ip = max no. of bytes to copy before needing another "strt" insn
*/
cmp r2, ip
movlt ip, r2
sub r2, r2, ip
subs ip, ip, #32
blt .Lcfu_0rem8lp
.Lcfu_0cpy8lp: ldmia r1!, {r3 - r6} @ Shouldnt fault
stmia r0!, {r3 - r6}
ldmia r1!, {r3 - r6} @ Shouldnt fault
subs ip, ip, #32
stmia r0!, {r3 - r6}
bpl .Lcfu_0cpy8lp
.Lcfu_0rem8lp: cmn ip, #16
ldmgeia r1!, {r3 - r6} @ Shouldnt fault
stmgeia r0!, {r3 - r6}
tst ip, #8
ldmneia r1!, {r3 - r4} @ Shouldnt fault
stmneia r0!, {r3 - r4}
tst ip, #4
TUSER( ldrne) r3, [r1], #4 @ Shouldnt fault
strne r3, [r0], #4
ands ip, ip, #3
beq .Lcfu_0fupi
.Lcfu_0nowords: teq ip, #0
beq .Lcfu_finished
.Lcfu_nowords: cmp ip, #2
USER( TUSER( ldrb) r3, [r1], #1) @ May fault
strb r3, [r0], #1
USER( TUSER( ldrgeb) r3, [r1], #1) @ May fault
strgeb r3, [r0], #1
USER( TUSER( ldrgtb) r3, [r1], #1) @ May fault
strgtb r3, [r0], #1
b .Lcfu_finished
.Lcfu_not_enough:
movs ip, r2
bne .Lcfu_nowords
.Lcfu_finished: mov r0, #0
add sp, sp, #8
ldmfd sp!, {r4 - r7, pc}
.Lcfu_src_not_aligned:
bic r1, r1, #3
USER( TUSER( ldr) r7, [r1], #4) @ May fault
cmp ip, #2
bgt .Lcfu_3fupi
beq .Lcfu_2fupi
.Lcfu_1fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lcfu_1nowords
mov r3, r7, pull #8
USER( TUSER( ldr) r7, [r1], #4) @ May fault
orr r3, r3, r7, push #24
str r3, [r0], #4
mov ip, r1, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
beq .Lcfu_1fupi
cmp r2, ip
movlt ip, r2
sub r2, r2, ip
subs ip, ip, #16
blt .Lcfu_1rem8lp
.Lcfu_1cpy8lp: mov r3, r7, pull #8
ldmia r1!, {r4 - r7} @ Shouldnt fault
subs ip, ip, #16
orr r3, r3, r4, push #24
mov r4, r4, pull #8
orr r4, r4, r5, push #24
mov r5, r5, pull #8
orr r5, r5, r6, push #24
mov r6, r6, pull #8
orr r6, r6, r7, push #24
stmia r0!, {r3 - r6}
bpl .Lcfu_1cpy8lp
.Lcfu_1rem8lp: tst ip, #8
movne r3, r7, pull #8
ldmneia r1!, {r4, r7} @ Shouldnt fault
orrne r3, r3, r4, push #24
movne r4, r4, pull #8
orrne r4, r4, r7, push #24
stmneia r0!, {r3 - r4}
tst ip, #4
movne r3, r7, pull #8
USER( TUSER( ldrne) r7, [r1], #4) @ May fault
orrne r3, r3, r7, push #24
strne r3, [r0], #4
ands ip, ip, #3
beq .Lcfu_1fupi
.Lcfu_1nowords: mov r3, r7, get_byte_1
teq ip, #0
beq .Lcfu_finished
cmp ip, #2
strb r3, [r0], #1
movge r3, r7, get_byte_2
strgeb r3, [r0], #1
movgt r3, r7, get_byte_3
strgtb r3, [r0], #1
b .Lcfu_finished
.Lcfu_2fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lcfu_2nowords
mov r3, r7, pull #16
USER( TUSER( ldr) r7, [r1], #4) @ May fault
orr r3, r3, r7, push #16
str r3, [r0], #4
mov ip, r1, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
beq .Lcfu_2fupi
cmp r2, ip
movlt ip, r2
sub r2, r2, ip
subs ip, ip, #16
blt .Lcfu_2rem8lp
.Lcfu_2cpy8lp: mov r3, r7, pull #16
ldmia r1!, {r4 - r7} @ Shouldnt fault
subs ip, ip, #16
orr r3, r3, r4, push #16
mov r4, r4, pull #16
orr r4, r4, r5, push #16
mov r5, r5, pull #16
orr r5, r5, r6, push #16
mov r6, r6, pull #16
orr r6, r6, r7, push #16
stmia r0!, {r3 - r6}
bpl .Lcfu_2cpy8lp
.Lcfu_2rem8lp: tst ip, #8
movne r3, r7, pull #16
ldmneia r1!, {r4, r7} @ Shouldnt fault
orrne r3, r3, r4, push #16
movne r4, r4, pull #16
orrne r4, r4, r7, push #16
stmneia r0!, {r3 - r4}
tst ip, #4
movne r3, r7, pull #16
USER( TUSER( ldrne) r7, [r1], #4) @ May fault
orrne r3, r3, r7, push #16
strne r3, [r0], #4
ands ip, ip, #3
beq .Lcfu_2fupi
.Lcfu_2nowords: mov r3, r7, get_byte_2
teq ip, #0
beq .Lcfu_finished
cmp ip, #2
strb r3, [r0], #1
movge r3, r7, get_byte_3
strgeb r3, [r0], #1
USER( TUSER( ldrgtb) r3, [r1], #0) @ May fault
strgtb r3, [r0], #1
b .Lcfu_finished
.Lcfu_3fupi: subs r2, r2, #4
addmi ip, r2, #4
bmi .Lcfu_3nowords
mov r3, r7, pull #24
USER( TUSER( ldr) r7, [r1], #4) @ May fault
orr r3, r3, r7, push #8
str r3, [r0], #4
mov ip, r1, lsl #32 - PAGE_SHIFT
rsb ip, ip, #0
movs ip, ip, lsr #32 - PAGE_SHIFT
beq .Lcfu_3fupi
cmp r2, ip
movlt ip, r2
sub r2, r2, ip
subs ip, ip, #16
blt .Lcfu_3rem8lp
.Lcfu_3cpy8lp: mov r3, r7, pull #24
ldmia r1!, {r4 - r7} @ Shouldnt fault
orr r3, r3, r4, push #8
mov r4, r4, pull #24
orr r4, r4, r5, push #8
mov r5, r5, pull #24
orr r5, r5, r6, push #8
mov r6, r6, pull #24
orr r6, r6, r7, push #8
stmia r0!, {r3 - r6}
subs ip, ip, #16
bpl .Lcfu_3cpy8lp
.Lcfu_3rem8lp: tst ip, #8
movne r3, r7, pull #24
ldmneia r1!, {r4, r7} @ Shouldnt fault
orrne r3, r3, r4, push #8
movne r4, r4, pull #24
orrne r4, r4, r7, push #8
stmneia r0!, {r3 - r4}
tst ip, #4
movne r3, r7, pull #24
USER( TUSER( ldrne) r7, [r1], #4) @ May fault
orrne r3, r3, r7, push #8
strne r3, [r0], #4
ands ip, ip, #3
beq .Lcfu_3fupi
.Lcfu_3nowords: mov r3, r7, get_byte_3
teq ip, #0
beq .Lcfu_finished
cmp ip, #2
strb r3, [r0], #1
USER( TUSER( ldrgeb) r3, [r1], #1) @ May fault
strgeb r3, [r0], #1
USER( TUSER( ldrgtb) r3, [r1], #1) @ May fault
strgtb r3, [r0], #1
b .Lcfu_finished
ENDPROC(__copy_from_user)
.pushsection .fixup,"ax"
.align 0
/*
* We took an exception. r0 contains a pointer to
* the byte not copied.
*/
9001: ldr r2, [sp], #4 @ void *to
sub r2, r0, r2 @ bytes copied
ldr r1, [sp], #4 @ unsigned long count
subs r4, r1, r2 @ bytes left to copy
movne r1, r4
blne __memzero
mov r0, r4
ldmfd sp!, {r4 - r7, pc}
.popsection
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