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authorAvi Kivity <avi@qumranet.com>2008-06-25 16:17:36 +0300
committerAvi Kivity <avi@qumranet.com>2008-06-25 16:17:36 +0300
commitda17c8501b5829a7745937341cc1881f53971208 (patch)
treea094ad030d3490a9799697a661df0859760b12a1 /qemu-lock.h
parentRemove overzealous virtio-net printf (diff)
parentClarify some TODO items. (diff)
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Merge branch 'qemu-cvs'
Conflicts: qemu/block.c qemu/configure qemu/cpu-defs.h qemu/cutils.c qemu/exec-all.h qemu/exec.c qemu/monitor.c qemu/target-i386/helper.c qemu/vl.c Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'qemu-lock.h')
-rw-r--r--qemu-lock.h249
1 files changed, 249 insertions, 0 deletions
diff --git a/qemu-lock.h b/qemu-lock.h
new file mode 100644
index 000000000..f565565e5
--- /dev/null
+++ b/qemu-lock.h
@@ -0,0 +1,249 @@
+/*
+ * Copyright (c) 2003 Fabrice Bellard
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/* Locking primitives. Most of this code should be redundant -
+ system emulation doesn't need/use locking, NPTL userspace uses
+ pthread mutexes, and non-NPTL userspace isn't threadsafe anyway.
+ In either case a spinlock is probably the wrong kind of lock.
+ Spinlocks are only good if you know annother CPU has the lock and is
+ likely to release it soon. In environments where you have more threads
+ than physical CPUs (the extreme case being a single CPU host) a spinlock
+ simply wastes CPU until the OS decides to preempt it. */
+#if defined(USE_NPTL)
+
+#include <pthread.h>
+#define spin_lock pthread_mutex_lock
+#define spin_unlock pthread_mutex_unlock
+#define spinlock_t pthread_mutex_t
+#define SPIN_LOCK_UNLOCKED PTHREAD_MUTEX_INITIALIZER
+
+#else
+
+#if defined(__hppa__)
+
+typedef int spinlock_t[4];
+
+#define SPIN_LOCK_UNLOCKED { 1, 1, 1, 1 }
+
+static inline void resetlock (spinlock_t *p)
+{
+ (*p)[0] = (*p)[1] = (*p)[2] = (*p)[3] = 1;
+}
+
+#else
+
+typedef int spinlock_t;
+
+#define SPIN_LOCK_UNLOCKED 0
+
+static inline void resetlock (spinlock_t *p)
+{
+ *p = SPIN_LOCK_UNLOCKED;
+}
+
+#endif
+
+#if defined(__powerpc__)
+static inline int testandset (int *p)
+{
+ int ret;
+ __asm__ __volatile__ (
+ "0: lwarx %0,0,%1\n"
+ " xor. %0,%3,%0\n"
+ " bne 1f\n"
+ " stwcx. %2,0,%1\n"
+ " bne- 0b\n"
+ "1: "
+ : "=&r" (ret)
+ : "r" (p), "r" (1), "r" (0)
+ : "cr0", "memory");
+ return ret;
+}
+#elif defined(__i386__)
+static inline int testandset (int *p)
+{
+ long int readval = 0;
+
+ __asm__ __volatile__ ("lock; cmpxchgl %2, %0"
+ : "+m" (*p), "+a" (readval)
+ : "r" (1)
+ : "cc");
+ return readval;
+}
+#elif defined(__x86_64__)
+static inline int testandset (int *p)
+{
+ long int readval = 0;
+
+ __asm__ __volatile__ ("lock; cmpxchgl %2, %0"
+ : "+m" (*p), "+a" (readval)
+ : "r" (1)
+ : "cc");
+ return readval;
+}
+#elif defined(__s390__)
+static inline int testandset (int *p)
+{
+ int ret;
+
+ __asm__ __volatile__ ("0: cs %0,%1,0(%2)\n"
+ " jl 0b"
+ : "=&d" (ret)
+ : "r" (1), "a" (p), "0" (*p)
+ : "cc", "memory" );
+ return ret;
+}
+#elif defined(__alpha__)
+static inline int testandset (int *p)
+{
+ int ret;
+ unsigned long one;
+
+ __asm__ __volatile__ ("0: mov 1,%2\n"
+ " ldl_l %0,%1\n"
+ " stl_c %2,%1\n"
+ " beq %2,1f\n"
+ ".subsection 2\n"
+ "1: br 0b\n"
+ ".previous"
+ : "=r" (ret), "=m" (*p), "=r" (one)
+ : "m" (*p));
+ return ret;
+}
+#elif defined(__sparc__)
+static inline int testandset (int *p)
+{
+ int ret;
+
+ __asm__ __volatile__("ldstub [%1], %0"
+ : "=r" (ret)
+ : "r" (p)
+ : "memory");
+
+ return (ret ? 1 : 0);
+}
+#elif defined(__arm__)
+static inline int testandset (int *spinlock)
+{
+ register unsigned int ret;
+ __asm__ __volatile__("swp %0, %1, [%2]"
+ : "=r"(ret)
+ : "0"(1), "r"(spinlock));
+
+ return ret;
+}
+#elif defined(__mc68000)
+static inline int testandset (int *p)
+{
+ char ret;
+ __asm__ __volatile__("tas %1; sne %0"
+ : "=r" (ret)
+ : "m" (p)
+ : "cc","memory");
+ return ret;
+}
+#elif defined(__hppa__)
+
+/* Because malloc only guarantees 8-byte alignment for malloc'd data,
+ and GCC only guarantees 8-byte alignment for stack locals, we can't
+ be assured of 16-byte alignment for atomic lock data even if we
+ specify "__attribute ((aligned(16)))" in the type declaration. So,
+ we use a struct containing an array of four ints for the atomic lock
+ type and dynamically select the 16-byte aligned int from the array
+ for the semaphore. */
+#define __PA_LDCW_ALIGNMENT 16
+static inline void *ldcw_align (void *p) {
+ unsigned long a = (unsigned long)p;
+ a = (a + __PA_LDCW_ALIGNMENT - 1) & ~(__PA_LDCW_ALIGNMENT - 1);
+ return (void *)a;
+}
+
+static inline int testandset (spinlock_t *p)
+{
+ unsigned int ret;
+ p = ldcw_align(p);
+ __asm__ __volatile__("ldcw 0(%1),%0"
+ : "=r" (ret)
+ : "r" (p)
+ : "memory" );
+ return !ret;
+}
+
+#elif defined(__ia64)
+
+#include "ia64intrin.h"
+
+static inline int testandset (int *p)
+{
+ return (int)cmpxchg_acq(p,0,1);
+}
+#elif defined(__mips__)
+static inline int testandset (int *p)
+{
+ int ret;
+
+ __asm__ __volatile__ (
+ " .set push \n"
+ " .set noat \n"
+ " .set mips2 \n"
+ "1: li $1, 1 \n"
+ " ll %0, %1 \n"
+ " sc $1, %1 \n"
+ " beqz $1, 1b \n"
+ " .set pop "
+ : "=r" (ret), "+R" (*p)
+ :
+ : "memory");
+
+ return ret;
+}
+#else
+#error unimplemented CPU support
+#endif
+
+#if defined(CONFIG_USER_ONLY)
+static inline void spin_lock(spinlock_t *lock)
+{
+ while (testandset(lock));
+}
+
+static inline void spin_unlock(spinlock_t *lock)
+{
+ resetlock(lock);
+}
+
+static inline int spin_trylock(spinlock_t *lock)
+{
+ return !testandset(lock);
+}
+#else
+static inline void spin_lock(spinlock_t *lock)
+{
+}
+
+static inline void spin_unlock(spinlock_t *lock)
+{
+}
+
+static inline int spin_trylock(spinlock_t *lock)
+{
+ return 1;
+}
+#endif
+
+#endif