synch_bitops.h

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    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 
   11 #define ADDR (*(volatile long *) addr)
   12 
   13 static __inline__ void synch_set_bit(int nr, volatile void * addr)
   14 {
   15     __asm__ __volatile__ ( 
   16         "lock btsl %1,%0"
   17         : "=m" (ADDR) : "Ir" (nr) : "memory" );
   18 }
   19 
   20 static __inline__ void synch_clear_bit(int nr, volatile void * addr)
   21 {
   22     __asm__ __volatile__ (
   23         "lock btrl %1,%0"
   24         : "=m" (ADDR) : "Ir" (nr) : "memory" );
   25 }
   26 
   27 static __inline__ void synch_change_bit(int nr, volatile void * addr)
   28 {
   29     __asm__ __volatile__ (
   30         "lock btcl %1,%0"
   31         : "=m" (ADDR) : "Ir" (nr) : "memory" );
   32 }
   33 
   34 static __inline__ int synch_test_and_set_bit(int nr, volatile void * addr)
   35 {
   36     int oldbit;
   37     __asm__ __volatile__ (
   38         "lock btsl %2,%1\n\tsbbl %0,%0"
   39         : "=r" (oldbit), "=m" (ADDR) : "Ir" (nr) : "memory");
   40     return oldbit;
   41 }
   42 
   43 static __inline__ int synch_test_and_clear_bit(int nr, volatile void * addr)
   44 {
   45     int oldbit;
   46     __asm__ __volatile__ (
   47         "lock btrl %2,%1\n\tsbbl %0,%0"
   48         : "=r" (oldbit), "=m" (ADDR) : "Ir" (nr) : "memory");
   49     return oldbit;
   50 }
   51 
   52 static __inline__ int synch_test_and_change_bit(int nr, volatile void * addr)
   53 {
   54     int oldbit;
   55 
   56     __asm__ __volatile__ (
   57         "lock btcl %2,%1\n\tsbbl %0,%0"
   58         : "=r" (oldbit), "=m" (ADDR) : "Ir" (nr) : "memory");
   59     return oldbit;
   60 }
   61 
   62 struct __synch_xchg_dummy { unsigned long a[100]; };
   63 #define __synch_xg(x) ((volatile struct __synch_xchg_dummy *)(x))
   64 
   65 #define synch_cmpxchg(ptr, old, new) \
   66 ((__typeof__(*(ptr)))__synch_cmpxchg((ptr),\
   67                                      (unsigned long)(old), \
   68                                      (unsigned long)(new), \
   69                                      sizeof(*(ptr))))
   70 
   71 static inline unsigned long __synch_cmpxchg(volatile void *ptr,
   72                                             unsigned long old,
   73                                             unsigned long new, int size)
   74 {
   75         unsigned long prev;
   76         switch (size) {
   77         case 1:
   78                 __asm__ __volatile__("lock; cmpxchgb %b1,%2"
   79                                      : "=a"(prev)
   80                                      : "q"(new), "m"(*__synch_xg(ptr)),
   81                                        ""(old)
   82                                      : "memory");
   83                 return prev;
   84         case 2:
   85                 __asm__ __volatile__("lock; cmpxchgw %w1,%2"
   86                                      : "=a"(prev)
   87                                      : "q"(new), "m"(*__synch_xg(ptr)),
   88                                        ""(old)
   89                                      : "memory");
   90                 return prev;
   91         case 4:
   92                 __asm__ __volatile__("lock; cmpxchgl %k1,%2"
   93                                      : "=a"(prev)
   94                                      : "q"(new), "m"(*__synch_xg(ptr)),
   95                                        ""(old)
   96                                      : "memory");
   97                 return prev;
   98         case 8:
   99                 __asm__ __volatile__("lock; cmpxchgq %1,%2"
  100                                      : "=a"(prev)
  101                                      : "q"(new), "m"(*__synch_xg(ptr)),
  102                                        ""(old)
  103                                      : "memory");
  104                 return prev;
  105         }
  106         return old;
  107 }
  108 
  109 static __inline__ int synch_const_test_bit(int nr, const volatile void * addr)
  110 {
  111     return ((1UL << (nr & 31)) & 
  112             (((const volatile unsigned int *) addr)[nr >> 5])) != 0;
  113 }
  114 
  115 static __inline__ int synch_var_test_bit(int nr, volatile void * addr)
  116 {
  117     int oldbit;
  118     __asm__ __volatile__ (
  119         "btl %2,%1\n\tsbbl %0,%0"
  120         : "=r" (oldbit) : "m" (ADDR), "Ir" (nr) );
  121     return oldbit;
  122 }
  123 
  124 #define synch_test_bit(nr,addr) \
  125 (__builtin_constant_p(nr) ? \
  126  synch_const_test_bit((nr),(addr)) : \
  127  synch_var_test_bit((nr),(addr)))
  128 
  129 #endif /* __XEN_SYNCH_BITOPS_H__ */

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FreeBSD/Linux Kernel Cross Reference sys/amd64/include/xen/synch_bitops.h

FreeBSD/Linux Kernel Cross Reference
sys/amd64/include/xen/synch_bitops.h