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| author |   jsing <jsing@openbsd.org> | 2010-07-02 05:04:33 +0000 |
|---|---|---|
| committer | jsing <jsing@openbsd.org> | 2010-07-02 05:04:33 +0000 |
| commit | 9e88ded37b42f43691982861596bebfef0b1e879 (patch) | |
| tree | 82ba22a742dabc1a9934852b1fac942f1b07dfc2 | |
| parent | Apparently volatile does not mean what it is supposed to mean... avoid a (diff) | |
| download | wireguard-openbsd-9e88ded37b42f43691982861596bebfef0b1e879.tar.xz wireguard-openbsd-9e88ded37b42f43691982861596bebfef0b1e879.zip | |
Add a comment to explain why the sync is necessary in the while loop.
| -rw-r--r-- | sys/arch/hppa/hppa/fpu.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/sys/arch/hppa/hppa/fpu.c b/sys/arch/hppa/hppa/fpu.c index 6296dcb4fa9..2e76b72b3cd 100644 --- a/sys/arch/hppa/hppa/fpu.c +++ b/sys/arch/hppa/hppa/fpu.c @@ -1,4 +1,4 @@ -/* $OpenBSD: fpu.c,v 1.3 2010/07/02 04:51:13 jsing Exp $ */ +/* $OpenBSD: fpu.c,v 1.4 2010/07/02 05:04:33 jsing Exp $ */ /* * Copyright (c) 2010 Joel Sing <jsing@openbsd.org> @@ -64,6 +64,11 @@ fpu_proc(struct proc *p, int save) if (hppa_ipi_send(fpuci, HPPA_IPI_FPU_SAVE)) panic("FPU shootdown failed!\n"); + /* + * The sync is essential here since the volatile on hfp_cpu + * is ignored by gcc. Without this we will deadlock since + * hfp_cpu is never reloaded within the loop. + */ while (hfp->hfp_cpu != NULL) asm volatile ("sync" ::: "memory"); |