| // 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 |