diff options
| author | Russ Cox <rsc@golang.org> | 2011-05-02 10:49:19 -0400 |
|---|---|---|
| committer | Russ Cox <rsc@golang.org> | 2011-05-02 10:49:19 -0400 |
| commit | 540feaae470ad4cf838b0c1bd5a74bdde096a082 (patch) | |
| tree | b040a35d8058d0ff0da3078bdbeb3a942872b161 /src/pkg/runtime/linux | |
| parent | 807ce2719c243f6d8640de774599e3335883eacb (diff) | |
| download | go-540feaae470ad4cf838b0c1bd5a74bdde096a082.tar.xz | |
runtime, sync/atomic: fix arm cas
Works around bug in kernel implementation on old ARM5 kernels.
Bug was fixed on 26 Nov 2007 (between 2.6.23 and 2.6.24) but
old kernels persist.
Fixes #1750.
R=dfc, golang-dev
CC=golang-dev
https://golang.org/cl/4436072
Diffstat (limited to 'src/pkg/runtime/linux')
| -rw-r--r-- | src/pkg/runtime/linux/arm/sys.s | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/src/pkg/runtime/linux/arm/sys.s b/src/pkg/runtime/linux/arm/sys.s index d866b0e220..2b5365bd86 100644 --- a/src/pkg/runtime/linux/arm/sys.s +++ b/src/pkg/runtime/linux/arm/sys.s @@ -258,11 +258,22 @@ TEXT cas<>(SB),7,$0 TEXT runtime·cas(SB),7,$0 MOVW valptr+0(FP), R2 MOVW old+4(FP), R0 +casagain: MOVW new+8(FP), R1 BL cas<>(SB) - MOVW $0, R0 - MOVW.CS $1, R0 + BCC cascheck + MOVW $1, R0 RET +cascheck: + // Kernel lies; double-check. + MOVW valptr+0(FP), R2 + MOVW old+4(FP), R0 + MOVW 0(R2), R3 + CMP R0, R3 + BEQ casagain + MOVW $0, R0 + RET + TEXT runtime·casp(SB),7,$0 B runtime·cas(SB) |