arch/parisc/include/asm/cmpxchg.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * forked from parisc asm/atomic.h which was:
   4  *      Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
   5  *      Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
   6  */
   7
   8 #ifndef _ASM_PARISC_CMPXCHG_H_
   9 #define _ASM_PARISC_CMPXCHG_H_
  10
  11 /* This should get optimized out since it's never called.
  12 ** Or get a link error if xchg is used "wrong".
  13 */
  14 extern void __xchg_called_with_bad_pointer(void);
  15
  16 /* __xchg32/64 defined in arch/parisc/lib/bitops.c */
  17 extern unsigned long __xchg8(char, char *);
  18 extern unsigned long __xchg32(int, int *);
  19 #ifdef CONFIG_64BIT
  20 extern unsigned long __xchg64(unsigned long, unsigned long *);
  21 #endif
  22
  23 /* optimizer better get rid of switch since size is a constant */
  24 static inline unsigned long
  25 __xchg(unsigned long x, __volatile__ void *ptr, int size)
  26 {
  27         switch (size) {
  28 #ifdef CONFIG_64BIT
  29         case 8: return __xchg64(x, (unsigned long *) ptr);
  30 #endif
  31         case 4: return __xchg32((int) x, (int *) ptr);
  32         case 1: return __xchg8((char) x, (char *) ptr);
  33         }
  34         __xchg_called_with_bad_pointer();
  35         return x;
  36 }
  37
  38 /*
  39 ** REVISIT - Abandoned use of LDCW in xchg() for now:
  40 ** o need to test sizeof(*ptr) to avoid clearing adjacent bytes
  41 ** o and while we are at it, could CONFIG_64BIT code use LDCD too?
  42 **
  43 **      if (__builtin_constant_p(x) && (x == NULL))
  44 **              if (((unsigned long)p & 0xf) == 0)
  45 **                      return __ldcw(p);
  46 */
  47 #define xchg(ptr, x) \
  48         ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))))
  49
  50 /* bug catcher for when unsupported size is used - won't link */
  51 extern void __cmpxchg_called_with_bad_pointer(void);
  52
  53 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
  54 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
  55                                    unsigned int new_);
  56 extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
  57
  58 /* don't worry...optimizer will get rid of most of this */
  59 static inline unsigned long
  60 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
  61 {
  62         switch (size) {
  63 #ifdef CONFIG_64BIT
  64         case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  65 #endif
  66         case 4: return __cmpxchg_u32((unsigned int *)ptr,
  67                                      (unsigned int)old, (unsigned int)new_);
  68         }
  69         __cmpxchg_called_with_bad_pointer();
  70         return old;
  71 }
  72
  73 #define cmpxchg(ptr, o, n)                                               \
  74 ({                                                                       \
  75         __typeof__(*(ptr)) _o_ = (o);                                    \
  76         __typeof__(*(ptr)) _n_ = (n);                                    \
  77         (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,        \
  78                                     (unsigned long)_n_, sizeof(*(ptr))); \
  79 })
  80
  81 #include <asm-generic/cmpxchg-local.h>
  82
  83 static inline unsigned long __cmpxchg_local(volatile void *ptr,
  84                                       unsigned long old,
  85                                       unsigned long new_, int size)
  86 {
  87         switch (size) {
  88 #ifdef CONFIG_64BIT
  89         case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  90 #endif
  91         case 4: return __cmpxchg_u32(ptr, old, new_);
  92         default:
  93                 return __cmpxchg_local_generic(ptr, old, new_, size);
  94         }
  95 }
  96
  97 /*
  98  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
  99  * them available.
 100  */
 101 #define cmpxchg_local(ptr, o, n)                                        \
 102         ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 103                         (unsigned long)(n), sizeof(*(ptr))))
 104 #ifdef CONFIG_64BIT
 105 #define cmpxchg64_local(ptr, o, n)                                      \
 106 ({                                                                      \
 107         BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 108         cmpxchg_local((ptr), (o), (n));                                 \
 109 })
 110 #else
 111 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 112 #endif
 113
 114 #define cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
 115
 116 #endif /* _ASM_PARISC_CMPXCHG_H_ */