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sync/atomic: make unaligned 64-bit atomic operation panic on ARM

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use MOVW.NE instead of BEQ and MOVW.

R=golang-dev, dave, rsc, daniel.morsing
CC=golang-dev
https://golang.org/cl/7718043
This commit is contained in:
Shenghou Ma 2013-04-01 14:34:03 -07:00 committed by Rob Pike
parent 3467068ef4
commit 94b7853924
3 changed files with 27 additions and 3 deletions
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16
src/pkg/sync/atomic/asm_arm.s
View File

@ -29,6 +29,10 @@ casfail:
TEXT ·armCompareAndSwapUint64(SB),7,$0
BL fastCheck64<>(SB)
MOVW addr+0(FP), R1
// make unaligned atomic access panic
AND.S $7, R1, R2
BEQ 2(PC)
MOVW R2, (R2)
MOVW oldlo+4(FP), R2
MOVW oldhi+8(FP), R3
MOVW newlo+12(FP), R4
@ -67,6 +71,10 @@ addloop:
TEXT ·armAddUint64(SB),7,$0
BL fastCheck64<>(SB)
MOVW addr+0(FP), R1
// make unaligned atomic access panic
AND.S $7, R1, R2
BEQ 2(PC)
MOVW R2, (R2)
MOVW deltalo+4(FP), R2
MOVW deltahi+8(FP), R3
add64loop:
@ -84,6 +92,10 @@ add64loop:
TEXT ·armLoadUint64(SB),7,$0
BL fastCheck64<>(SB)
MOVW addr+0(FP), R1
// make unaligned atomic access panic
AND.S $7, R1, R2
BEQ 2(PC)
MOVW R2, (R2)
load64loop:
LDREXD (R1), R2 // loads R2 and R3
STREXD R2, (R1), R0 // stores R2 and R3
@ -96,6 +108,10 @@ load64loop:
TEXT ·armStoreUint64(SB),7,$0
BL fastCheck64<>(SB)
MOVW addr+0(FP), R1
// make unaligned atomic access panic
AND.S $7, R1, R2
BEQ 2(PC)
MOVW R2, (R2)
MOVW vallo+4(FP), R2
MOVW valhi+8(FP), R3
store64loop:

8
src/pkg/sync/atomic/asm_linux_arm.s
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@ -80,6 +80,10 @@ TEXT cas64<>(SB),7,$0
TEXT kernelCAS64<>(SB),7,$0
// int (*__kuser_cmpxchg64_t)(const int64_t *oldval, const int64_t *newval, volatile int64_t *ptr);
MOVW addr+0(FP), R2 // ptr
// make unaligned atomic access panic
AND.S $7, R2, R1
BEQ 2(PC)
MOVW R1, (R1)
MOVW $4(FP), R0 // oldval
MOVW $12(FP), R1 // newval
BL cas64<>(SB)
@ -91,6 +95,10 @@ TEXT kernelCAS64<>(SB),7,$0
TEXT generalCAS64<>(SB),7,$20
// bool runtime·cas64(uint64 volatile *addr, uint64 *old, uint64 new)
MOVW addr+0(FP), R0
// make unaligned atomic access panic
AND.S $7, R0, R1
BEQ 2(PC)
MOVW R1, (R1)
MOVW R0, 4(R13)
MOVW $4(FP), R1 // oldval
MOVW R1, 8(R13)

6
src/pkg/sync/atomic/atomic_test.go
View File

@ -1189,10 +1189,10 @@ func shouldPanic(t *testing.T, name string, f func()) {
func TestUnaligned64(t *testing.T) {
// Unaligned 64-bit atomics on 32-bit systems are
// a continual source of pain. Test that on 386 they crash
// a continual source of pain. Test that on 32-bit systems they crash
// instead of failing silently.
if runtime.GOARCH != "386" {
t.Skip("test only runs on 386")
if unsafe.Sizeof(int(0)) != 4 {
t.Skip("test only runs on 32-bit systems")
}
x := make([]uint32, 4)