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| author |   guenther <guenther@openbsd.org> | 2013-05-06 00:23:49 +0000 |
|---|---|---|
| committer | guenther <guenther@openbsd.org> | 2013-05-06 00:23:49 +0000 |
| commit | 9cea5a4d20b399784136c8ceaebbc1e93a61aec9 (patch) | |
| tree | ff358f68dd60445e71629b314014000774c0aeea | |
| parent | the use of modern intel performance counter msrs to measure the number of (diff) | |
| download | wireguard-openbsd-9cea5a4d20b399784136c8ceaebbc1e93a61aec9.tar.xz wireguard-openbsd-9cea5a4d20b399784136c8ceaebbc1e93a61aec9.zip | |
If the lock is contended, such that the 'sc' fails, then we need to
reset the %2 register with _SPINLOCK_LOCKED before retrying.
tobiasu@ hit the problem and figured out that ".set noreorder" is
needed in the ASM
| -rw-r--r-- | lib/librthread/arch/mips64/_atomic_lock.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/lib/librthread/arch/mips64/_atomic_lock.c b/lib/librthread/arch/mips64/_atomic_lock.c index 3e1c4a07a3f..3b000eb0914 100644 --- a/lib/librthread/arch/mips64/_atomic_lock.c +++ b/lib/librthread/arch/mips64/_atomic_lock.c @@ -1,4 +1,4 @@ -/* $OpenBSD: _atomic_lock.c,v 1.4 2009/06/01 23:17:53 miod Exp $ */ +/* $OpenBSD: _atomic_lock.c,v 1.5 2013/05/06 00:23:49 guenther Exp $ */ /* * Atomic lock for mips @@ -13,12 +13,15 @@ _atomic_lock(volatile _spinlock_lock_t *lock) _spinlock_lock_t old; __asm__ __volatile__ ( + ".set noreorder\n" "1: ll %0, 0(%1)\n" " sc %2, 0(%1)\n" " beqz %2, 1b\n" - " nop\n" : - "=r"(old) : - "r"(lock), "r"(_SPINLOCK_LOCKED) : "memory"); + " addi %2, $0, %3\n" + ".set reorder\n" + : "=&r"(old) + : "r"(lock), "r"(_SPINLOCK_LOCKED), "i"(_SPINLOCK_LOCKED) + : "memory"); return (old != _SPINLOCK_UNLOCKED); } |