Mailing List Archive

--- /dev/null 2005-08-06 08:51:33.545833696 -0700
+++ a/include/asm-i386/synch_bitops.h 2005-07-28 13:17:07.000000000 -0700
@@ -0,0 +1,140 @@
+#ifndef __XEN_SYNCH_BITOPS_H__
+#define __XEN_SYNCH_BITOPS_H__
+
+/*
+ * Copyright 1992, Linus Torvalds.
+ * Heavily modified to provide guaranteed strong synchronisation
+ * when communicating with Xen or other guest OSes running on other CPUs.
+ */
+
+#include <linux/config.h>
+
+#define ADDR (*(volatile long *) addr)
+
+static __inline__ void synch_set_bit(int nr, volatile void * addr)
+{
+ __asm__ __volatile__ (
+ "lock btsl %1,%0"
+ : "=m" (ADDR) : "Ir" (nr) : "memory" );
+}
+
+static __inline__ void synch_clear_bit(int nr, volatile void * addr)
+{
+ __asm__ __volatile__ (
+ "lock btrl %1,%0"
+ : "=m" (ADDR) : "Ir" (nr) : "memory" );
+}
+
+static __inline__ void synch_change_bit(int nr, volatile void * addr)
+{
+ __asm__ __volatile__ (
+ "lock btcl %1,%0"
+ : "=m" (ADDR) : "Ir" (nr) : "memory" );
+}
+
+static __inline__ int synch_test_and_set_bit(int nr, volatile void * addr)
+{
+ int oldbit;
+ __asm__ __volatile__ (
+ "lock btsl %2,%1\n\tsbbl %0,%0"
+ : "=r" (oldbit), "=m" (ADDR) : "Ir" (nr) : "memory");
+ return oldbit;
+}
+
+static __inline__ int synch_test_and_clear_bit(int nr, volatile void * addr)
+{
+ int oldbit;
+ __asm__ __volatile__ (
+ "lock btrl %2,%1\n\tsbbl %0,%0"
+ : "=r" (oldbit), "=m" (ADDR) : "Ir" (nr) : "memory");
+ return oldbit;
+}
+
+static __inline__ int synch_test_and_change_bit(int nr, volatile void * addr)
+{
+ int oldbit;
+
+ __asm__ __volatile__ (
+ "lock btcl %2,%1\n\tsbbl %0,%0"
+ : "=r" (oldbit), "=m" (ADDR) : "Ir" (nr) : "memory");
+ return oldbit;
+}
+
+struct __synch_xchg_dummy { unsigned long a[100]; };
+#define __synch_xg(x) ((struct __synch_xchg_dummy *)(x))
+
+#define synch_cmpxchg(ptr, old, new) \
+((__typeof__(*(ptr)))__synch_cmpxchg((ptr),\
+ (unsigned long)(old), \
+ (unsigned long)(new), \
+ sizeof(*(ptr))))
+
+static inline unsigned long __synch_cmpxchg(volatile void *ptr,
+ unsigned long old,
+ unsigned long new, int size)
+{
+ unsigned long prev;
+ switch (size) {
+ case 1:
+ __asm__ __volatile__("lock; cmpxchgb %b1,%2"
+ : "=a"(prev)
+ : "q"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+ case 2:
+ __asm__ __volatile__("lock; cmpxchgw %w1,%2"
+ : "=a"(prev)
+ : "q"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+#ifdef CONFIG_X86_64
+ case 4:
+ __asm__ __volatile__("lock; cmpxchgl %k1,%2"
+ : "=a"(prev)
+ : "q"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+ case 8:
+ __asm__ __volatile__("lock; cmpxchgq %1,%2"
+ : "=a"(prev)
+ : "q"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+#else
+ case 4:
+ __asm__ __volatile__("lock; cmpxchgl %1,%2"
+ : "=a"(prev)
+ : "q"(new), "m"(*__synch_xg(ptr)),
+ "0"(old)
+ : "memory");
+ return prev;
+#endif
+ }
+ return old;
+}
+
+static __inline__ int synch_const_test_bit(int nr, const volatile void * addr)
+{
+ return ((1UL << (nr & 31)) &
+ (((const volatile unsigned int *) addr)[nr >> 5])) != 0;
+}
+
+static __inline__ int synch_var_test_bit(int nr, volatile void * addr)
+{
+ int oldbit;
+ __asm__ __volatile__ (
+ "btl %2,%1\n\tsbbl %0,%0"
+ : "=r" (oldbit) : "m" (ADDR), "Ir" (nr) );
+ return oldbit;
+}
+
+#define synch_test_bit(nr,addr) \
+(__builtin_constant_p(nr) ? \
+ synch_const_test_bit((nr),(addr)) : \
+ synch_var_test_bit((nr),(addr)))
+
+#endif /* __XEN_SYNCH_BITOPS_H__ */

--


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