| // Copyright 2014 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // +build !gccgo |
| |
| #include "textflag.h" |
| |
| TEXT ·RewindAndSetgid(SB),NOSPLIT|NOFRAME,$0-0 |
| // Save link register |
| MOVD R30, R9 |
| |
| // Rewind stack pointer so anything that happens on the stack |
| // will clobber the test pattern created by the caller |
| ADD $(1024 * 8), RSP |
| |
| // Ask signaller to setgid |
| MOVD $·Baton(SB), R0 |
| MOVD $1, R1 |
| storeloop: |
| LDAXRW (R0), R2 |
| STLXRW R1, (R0), R3 |
| CBNZ R3, storeloop |
| |
| // Wait for setgid completion |
| MOVW $0, R1 |
| MOVW $0, R2 |
| loop: |
| LDAXRW (R0), R3 |
| CMPW R1, R3 |
| BNE loop |
| STLXRW R2, (R0), R3 |
| CBNZ R3, loop |
| |
| // Restore stack |
| SUB $(1024 * 8), RSP |
| |
| MOVD R9, R30 |
| RET |
