root/arch/sparc/include/asm/cmpxchg_32.h

INCLUDED FROM

DEFINITIONS

1. __xchg
2. __cmpxchg

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /* 32-bit atomic xchg() and cmpxchg() definitions.
   3  *
   4  * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
   5  * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
   6  * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
   7  *
   8  * Additions by Keith M Wesolowski (wesolows@foobazco.org) based
   9  * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
  10  */
  11 
  12 #ifndef __ARCH_SPARC_CMPXCHG__
  13 #define __ARCH_SPARC_CMPXCHG__
  14 
  15 unsigned long __xchg_u32(volatile u32 *m, u32 new);
  16 void __xchg_called_with_bad_pointer(void);
  17 
  18 static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr, int size)
  19 {
  20         switch (size) {
  21         case 4:
  22                 return __xchg_u32(ptr, x);
  23         }
  24         __xchg_called_with_bad_pointer();
  25         return x;
  26 }
  27 
  28 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  29 
  30 /* Emulate cmpxchg() the same way we emulate atomics,
  31  * by hashing the object address and indexing into an array
  32  * of spinlocks to get a bit of performance...
  33  *
  34  * See arch/sparc/lib/atomic32.c for implementation.
  35  *
  36  * Cribbed from <asm-parisc/atomic.h>
  37  */
  38 
  39 /* bug catcher for when unsupported size is used - won't link */
  40 void __cmpxchg_called_with_bad_pointer(void);
  41 /* we only need to support cmpxchg of a u32 on sparc */
  42 unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
  43 
  44 /* don't worry...optimizer will get rid of most of this */
  45 static inline unsigned long
  46 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
  47 {
  48         switch (size) {
  49         case 4:
  50                 return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
  51         default:
  52                 __cmpxchg_called_with_bad_pointer();
  53                 break;
  54         }
  55         return old;
  56 }
  57 
  58 #define cmpxchg(ptr, o, n)                                              \
  59 ({                                                                      \
  60         __typeof__(*(ptr)) _o_ = (o);                                   \
  61         __typeof__(*(ptr)) _n_ = (n);                                   \
  62         (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,       \
  63                         (unsigned long)_n_, sizeof(*(ptr)));            \
  64 })
  65 
  66 u64 __cmpxchg_u64(u64 *ptr, u64 old, u64 new);
  67 #define cmpxchg64(ptr, old, new)        __cmpxchg_u64(ptr, old, new)
  68 
  69 #include <asm-generic/cmpxchg-local.h>
  70 
  71 /*
  72  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  73  * them available.
  74  */
  75 #define cmpxchg_local(ptr, o, n)                                               \
  76         ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
  77                         (unsigned long)(n), sizeof(*(ptr))))
  78 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
  79 
  80 #endif /* __ARCH_SPARC_CMPXCHG__ */