arch/x86/include/mach-xen/asm/synch_bitops.h

   1 #ifndef __XEN_SYNCH_BITOPS_H__
   2 #define __XEN_SYNCH_BITOPS_H__
   3
   4 /*
   5  * Copyright 1992, Linus Torvalds.
   6  * Heavily modified to provide guaranteed strong synchronisation
   7  * when communicating with Xen or other guest OSes running on other CPUs.
   8  */
   9
  10 #ifdef HAVE_XEN_PLATFORM_COMPAT_H
  11 #include <xen/platform-compat.h>
  12 #endif
  13
  14 #define ADDR (*(volatile long *) addr)
  15
  16 static __inline__ void synch_set_bit(int nr, volatile void * addr)
  17 {
  18     __asm__ __volatile__ (
  19         "lock btsl %1,%0"
  20         : "+m" (ADDR) : "Ir" (nr) : "memory" );
  21 }
  22
  23 static __inline__ void synch_clear_bit(int nr, volatile void * addr)
  24 {
  25     __asm__ __volatile__ (
  26         "lock btrl %1,%0"
  27         : "+m" (ADDR) : "Ir" (nr) : "memory" );
  28 }
  29
  30 static __inline__ void synch_change_bit(int nr, volatile void * addr)
  31 {
  32     __asm__ __volatile__ (
  33         "lock btcl %1,%0"
  34         : "+m" (ADDR) : "Ir" (nr) : "memory" );
  35 }
  36
  37 static __inline__ int synch_test_and_set_bit(int nr, volatile void * addr)
  38 {
  39     int oldbit;
  40     __asm__ __volatile__ (
  41         "lock btsl %2,%1\n\tsbbl %0,%0"
  42         : "=r" (oldbit), "+m" (ADDR) : "Ir" (nr) : "memory");
  43     return oldbit;
  44 }
  45
  46 static __inline__ int synch_test_and_clear_bit(int nr, volatile void * addr)
  47 {
  48     int oldbit;
  49     __asm__ __volatile__ (
  50         "lock btrl %2,%1\n\tsbbl %0,%0"
  51         : "=r" (oldbit), "+m" (ADDR) : "Ir" (nr) : "memory");
  52     return oldbit;
  53 }
  54
  55 static __inline__ int synch_test_and_change_bit(int nr, volatile void * addr)
  56 {
  57     int oldbit;
  58
  59     __asm__ __volatile__ (
  60         "lock btcl %2,%1\n\tsbbl %0,%0"
  61         : "=r" (oldbit), "+m" (ADDR) : "Ir" (nr) : "memory");
  62     return oldbit;
  63 }
  64
  65 struct __synch_xchg_dummy { unsigned long a[100]; };
  66 #define __synch_xg(x) ((struct __synch_xchg_dummy *)(x))
  67
  68 #define synch_cmpxchg(ptr, old, new) \
  69 ((__typeof__(*(ptr)))__synch_cmpxchg((ptr),\
  70                                      (unsigned long)(old), \
  71                                      (unsigned long)(new), \
  72                                      sizeof(*(ptr))))
  73
  74 static inline unsigned long __synch_cmpxchg(volatile void *ptr,
  75                                             unsigned long old,
  76                                             unsigned long new, int size)
  77 {
  78         unsigned long prev;
  79         switch (size) {
  80         case 1:
  81                 __asm__ __volatile__("lock; cmpxchgb %b1,%2"
  82                                      : "=a"(prev)
  83                                      : "q"(new), "m"(*__synch_xg(ptr)),
  84                                        "0"(old)
  85                                      : "memory");
  86                 return prev;
  87         case 2:
  88                 __asm__ __volatile__("lock; cmpxchgw %w1,%2"
  89                                      : "=a"(prev)
  90                                      : "r"(new), "m"(*__synch_xg(ptr)),
  91                                        "0"(old)
  92                                      : "memory");
  93                 return prev;
  94 #ifdef CONFIG_X86_64
  95         case 4:
  96                 __asm__ __volatile__("lock; cmpxchgl %k1,%2"
  97                                      : "=a"(prev)
  98                                      : "r"(new), "m"(*__synch_xg(ptr)),
  99                                        "0"(old)
 100                                      : "memory");
 101                 return prev;
 102         case 8:
 103                 __asm__ __volatile__("lock; cmpxchgq %1,%2"
 104                                      : "=a"(prev)
 105                                      : "r"(new), "m"(*__synch_xg(ptr)),
 106                                        "0"(old)
 107                                      : "memory");
 108                 return prev;
 109 #else
 110         case 4:
 111                 __asm__ __volatile__("lock; cmpxchgl %1,%2"
 112                                      : "=a"(prev)
 113                                      : "r"(new), "m"(*__synch_xg(ptr)),
 114                                        "0"(old)
 115                                      : "memory");
 116                 return prev;
 117 #endif
 118         }
 119         return old;
 120 }
 121
 122 #define synch_test_bit test_bit
 123
 124 #define synch_cmpxchg_subword synch_cmpxchg
 125
 126 #endif /* __XEN_SYNCH_BITOPS_H__ */