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authorkaf24@firebug.cl.cam.ac.uk <kaf24@firebug.cl.cam.ac.uk>2005-12-08 15:24:02 +0100
committerkaf24@firebug.cl.cam.ac.uk <kaf24@firebug.cl.cam.ac.uk>2005-12-08 15:24:02 +0100
commit7fc4533b321fbe7ef6ce0ef05e3b99cebe13a39e (patch)
treeb862d841d85f51754110df948f0b471c5e4583de /extras/mini-os/include/spinlock.h
parentbc70813814bf808d64f0331c2e450662058e07a7 (diff)
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Merge in the newer Xenbus implementation from Linux to the Mini-OS. The new
version compiles and starts up, but I'm not really sure how to test the new xenbus implementation. * Added unbind_evtchn * Copied parts of the Linux spinlock implementation to make the changes to xenbus compared to Linux smaller. Also added a dummy rwsem implementation. * Updated the xenbus-files Signed-off-by: Simon Kagstrom <simon.kagstrom@bth.se>
Diffstat (limited to 'extras/mini-os/include/spinlock.h')
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diff --git a/extras/mini-os/include/spinlock.h b/extras/mini-os/include/spinlock.h
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+++ b/extras/mini-os/include/spinlock.h
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+#ifndef __ASM_SPINLOCK_H
+#define __ASM_SPINLOCK_H
+
+#include <lib.h>
+
+/*
+ * Your basic SMP spinlocks, allowing only a single CPU anywhere
+ */
+
+typedef struct {
+ volatile unsigned int slock;
+} spinlock_t;
+
+#define SPINLOCK_MAGIC 0xdead4ead
+
+#define SPIN_LOCK_UNLOCKED (spinlock_t) { 1 }
+
+#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0)
+
+/*
+ * Simple spin lock operations. There are two variants, one clears IRQ's
+ * on the local processor, one does not.
+ *
+ * We make no fairness assumptions. They have a cost.
+ */
+
+#define spin_is_locked(x) (*(volatile signed char *)(&(x)->slock) <= 0)
+#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x))
+
+#define spin_lock_string \
+ "1:\n" \
+ LOCK \
+ "decb %0\n\t" \
+ "jns 3f\n" \
+ "2:\t" \
+ "rep;nop\n\t" \
+ "cmpb $0,%0\n\t" \
+ "jle 2b\n\t" \
+ "jmp 1b\n" \
+ "3:\n\t"
+
+#define spin_lock_string_flags \
+ "1:\n" \
+ LOCK \
+ "decb %0\n\t" \
+ "jns 4f\n\t" \
+ "2:\t" \
+ "testl $0x200, %1\n\t" \
+ "jz 3f\n\t" \
+ "#sti\n\t" \
+ "3:\t" \
+ "rep;nop\n\t" \
+ "cmpb $0, %0\n\t" \
+ "jle 3b\n\t" \
+ "#cli\n\t" \
+ "jmp 1b\n" \
+ "4:\n\t"
+
+/*
+ * This works. Despite all the confusion.
+ * (except on PPro SMP or if we are using OOSTORE)
+ * (PPro errata 66, 92)
+ */
+
+#define spin_unlock_string \
+ "xchgb %b0, %1" \
+ :"=q" (oldval), "=m" (lock->slock) \
+ :"0" (oldval) : "memory"
+
+static inline void _raw_spin_unlock(spinlock_t *lock)
+{
+ char oldval = 1;
+ __asm__ __volatile__(
+ spin_unlock_string
+ );
+}
+
+static inline int _raw_spin_trylock(spinlock_t *lock)
+{
+ char oldval;
+ __asm__ __volatile__(
+ "xchgb %b0,%1\n"
+ :"=q" (oldval), "=m" (lock->slock)
+ :"0" (0) : "memory");
+ return oldval > 0;
+}
+
+static inline void _raw_spin_lock(spinlock_t *lock)
+{
+ __asm__ __volatile__(
+ spin_lock_string
+ :"=m" (lock->slock) : : "memory");
+}
+
+static inline void _raw_spin_lock_flags (spinlock_t *lock, unsigned long flags)
+{
+ __asm__ __volatile__(
+ spin_lock_string_flags
+ :"=m" (lock->slock) : "r" (flags) : "memory");
+}
+
+#define _spin_trylock(lock) ({_raw_spin_trylock(lock) ? \
+ 1 : ({ 0;});})
+
+#define _spin_lock(lock) \
+do { \
+ _raw_spin_lock(lock); \
+} while(0)
+
+#define _spin_unlock(lock) \
+do { \
+ _raw_spin_unlock(lock); \
+} while (0)
+
+
+#define spin_lock(lock) _spin_lock(lock)
+#define spin_unlock(lock) _spin_unlock(lock)
+
+#define DEFINE_SPINLOCK(x) spinlock_t x = SPIN_LOCK_UNLOCKED
+
+#endif