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linux-next/arch/arm/lib/memmove.S
Lin Yongting 207a6cb069 ARM: 8224/1: Add unwinding support for memmove function
The memmove function never had unwinding annotations added.
Currently, when accessing invalid pointer by memmove occurs the
backtrace shown will stop at memmove or some completely unrelated
function. Add unwinding annotations in hopes of getting a more
useful backtrace in following cases:
1. die on accessing invalid pointer by memmove
2. kprobe trapped at any instruction within memmove
3. interrupted at any instruction within memmove

Signed-off-by: Lin Yongting <linyongting@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2014-11-27 16:00:24 +00:00

228 lines
4.8 KiB
ArmAsm

/*
* linux/arch/arm/lib/memmove.S
*
* Author: Nicolas Pitre
* Created: Sep 28, 2005
* Copyright: (C) MontaVista Software Inc.
*
* 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.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/unwind.h>
.text
/*
* Prototype: void *memmove(void *dest, const void *src, size_t n);
*
* Note:
*
* If the memory regions don't overlap, we simply branch to memcpy which is
* normally a bit faster. Otherwise the copy is done going downwards. This
* is a transposition of the code from copy_template.S but with the copy
* occurring in the opposite direction.
*/
ENTRY(memmove)
UNWIND( .fnstart )
subs ip, r0, r1
cmphi r2, ip
bls memcpy
stmfd sp!, {r0, r4, lr}
UNWIND( .fnend )
UNWIND( .fnstart )
UNWIND( .save {r0, r4, lr} ) @ in first stmfd block
add r1, r1, r2
add r0, r0, r2
subs r2, r2, #4
blt 8f
ands ip, r0, #3
PLD( pld [r1, #-4] )
bne 9f
ands ip, r1, #3
bne 10f
1: subs r2, r2, #(28)
stmfd sp!, {r5 - r8}
UNWIND( .fnend )
UNWIND( .fnstart )
UNWIND( .save {r0, r4, lr} )
UNWIND( .save {r5 - r8} ) @ in second stmfd block
blt 5f
CALGN( ands ip, r0, #31 )
CALGN( sbcnes r4, ip, r2 ) @ C is always set here
CALGN( bcs 2f )
CALGN( adr r4, 6f )
CALGN( subs r2, r2, ip ) @ C is set here
CALGN( rsb ip, ip, #32 )
CALGN( add pc, r4, ip )
PLD( pld [r1, #-4] )
2: PLD( subs r2, r2, #96 )
PLD( pld [r1, #-32] )
PLD( blt 4f )
PLD( pld [r1, #-64] )
PLD( pld [r1, #-96] )
3: PLD( pld [r1, #-128] )
4: ldmdb r1!, {r3, r4, r5, r6, r7, r8, ip, lr}
subs r2, r2, #32
stmdb r0!, {r3, r4, r5, r6, r7, r8, ip, lr}
bge 3b
PLD( cmn r2, #96 )
PLD( bge 4b )
5: ands ip, r2, #28
rsb ip, ip, #32
addne pc, pc, ip @ C is always clear here
b 7f
6: W(nop)
W(ldr) r3, [r1, #-4]!
W(ldr) r4, [r1, #-4]!
W(ldr) r5, [r1, #-4]!
W(ldr) r6, [r1, #-4]!
W(ldr) r7, [r1, #-4]!
W(ldr) r8, [r1, #-4]!
W(ldr) lr, [r1, #-4]!
add pc, pc, ip
nop
W(nop)
W(str) r3, [r0, #-4]!
W(str) r4, [r0, #-4]!
W(str) r5, [r0, #-4]!
W(str) r6, [r0, #-4]!
W(str) r7, [r0, #-4]!
W(str) r8, [r0, #-4]!
W(str) lr, [r0, #-4]!
CALGN( bcs 2b )
7: ldmfd sp!, {r5 - r8}
UNWIND( .fnend ) @ end of second stmfd block
UNWIND( .fnstart )
UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
8: movs r2, r2, lsl #31
ldrneb r3, [r1, #-1]!
ldrcsb r4, [r1, #-1]!
ldrcsb ip, [r1, #-1]
strneb r3, [r0, #-1]!
strcsb r4, [r0, #-1]!
strcsb ip, [r0, #-1]
ldmfd sp!, {r0, r4, pc}
9: cmp ip, #2
ldrgtb r3, [r1, #-1]!
ldrgeb r4, [r1, #-1]!
ldrb lr, [r1, #-1]!
strgtb r3, [r0, #-1]!
strgeb r4, [r0, #-1]!
subs r2, r2, ip
strb lr, [r0, #-1]!
blt 8b
ands ip, r1, #3
beq 1b
10: bic r1, r1, #3
cmp ip, #2
ldr r3, [r1, #0]
beq 17f
blt 18f
UNWIND( .fnend )
.macro backward_copy_shift push pull
UNWIND( .fnstart )
UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
subs r2, r2, #28
blt 14f
CALGN( ands ip, r0, #31 )
CALGN( sbcnes r4, ip, r2 ) @ C is always set here
CALGN( subcc r2, r2, ip )
CALGN( bcc 15f )
11: stmfd sp!, {r5 - r9}
UNWIND( .fnend )
UNWIND( .fnstart )
UNWIND( .save {r0, r4, lr} )
UNWIND( .save {r5 - r9} ) @ in new second stmfd block
PLD( pld [r1, #-4] )
PLD( subs r2, r2, #96 )
PLD( pld [r1, #-32] )
PLD( blt 13f )
PLD( pld [r1, #-64] )
PLD( pld [r1, #-96] )
12: PLD( pld [r1, #-128] )
13: ldmdb r1!, {r7, r8, r9, ip}
mov lr, r3, lspush #\push
subs r2, r2, #32
ldmdb r1!, {r3, r4, r5, r6}
orr lr, lr, ip, lspull #\pull
mov ip, ip, lspush #\push
orr ip, ip, r9, lspull #\pull
mov r9, r9, lspush #\push
orr r9, r9, r8, lspull #\pull
mov r8, r8, lspush #\push
orr r8, r8, r7, lspull #\pull
mov r7, r7, lspush #\push
orr r7, r7, r6, lspull #\pull
mov r6, r6, lspush #\push
orr r6, r6, r5, lspull #\pull
mov r5, r5, lspush #\push
orr r5, r5, r4, lspull #\pull
mov r4, r4, lspush #\push
orr r4, r4, r3, lspull #\pull
stmdb r0!, {r4 - r9, ip, lr}
bge 12b
PLD( cmn r2, #96 )
PLD( bge 13b )
ldmfd sp!, {r5 - r9}
UNWIND( .fnend ) @ end of the second stmfd block
UNWIND( .fnstart )
UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
14: ands ip, r2, #28
beq 16f
15: mov lr, r3, lspush #\push
ldr r3, [r1, #-4]!
subs ip, ip, #4
orr lr, lr, r3, lspull #\pull
str lr, [r0, #-4]!
bgt 15b
CALGN( cmp r2, #0 )
CALGN( bge 11b )
16: add r1, r1, #(\pull / 8)
b 8b
UNWIND( .fnend )
.endm
backward_copy_shift push=8 pull=24
17: backward_copy_shift push=16 pull=16
18: backward_copy_shift push=24 pull=8
ENDPROC(memmove)