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, volatile char *);
  18 extern unsigned long __xchg32(int, volatile int *);
  19 #ifdef CONFIG_64BIT
  20 extern unsigned long __xchg64(unsigned long, volatile 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, (volatile unsigned long *) ptr);
  30 #endif
  31         case 4: return __xchg32((int) x, (volatile int *) ptr);
  32         case 1: return __xchg8((char) x, (volatile 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 ({                                                                      \
  49         __typeof__(*(ptr)) __ret;                                       \
  50         __typeof__(*(ptr)) _x_ = (x);                                   \
  51         __ret = (__typeof__(*(ptr)))                                    \
  52                 __xchg((unsigned long)_x_, (ptr), sizeof(*(ptr)));      \
  53         __ret;                                                          \
  54 })
  55
  56 /* bug catcher for when unsupported size is used - won't link */
  57 extern void __cmpxchg_called_with_bad_pointer(void);
  58
  59 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
  60 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
  61                                    unsigned int new_);
  62 extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
  63 extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_);
  64
  65 /* don't worry...optimizer will get rid of most of this */
  66 static inline unsigned long
  67 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
  68 {
  69         switch (size) {
  70 #ifdef CONFIG_64BIT
  71         case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  72 #endif
  73         case 4: return __cmpxchg_u32((unsigned int *)ptr,
  74                                      (unsigned int)old, (unsigned int)new_);
  75         case 1: return __cmpxchg_u8((u8 *)ptr, (u8)old, (u8)new_);
  76         }
  77         __cmpxchg_called_with_bad_pointer();
  78         return old;
  79 }
  80
  81 #define cmpxchg(ptr, o, n)                                               \
  82 ({                                                                       \
  83         __typeof__(*(ptr)) _o_ = (o);                                    \
  84         __typeof__(*(ptr)) _n_ = (n);                                    \
  85         (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,        \
  86                                     (unsigned long)_n_, sizeof(*(ptr))); \
  87 })
  88
  89 #include <asm-generic/cmpxchg-local.h>
  90
  91 static inline unsigned long __cmpxchg_local(volatile void *ptr,
  92                                       unsigned long old,
  93                                       unsigned long new_, int size)
  94 {
  95         switch (size) {
  96 #ifdef CONFIG_64BIT
  97         case 8: return __cmpxchg_u64((u64 *)ptr, old, new_);
  98 #endif
  99         case 4: return __cmpxchg_u32(ptr, old, new_);
 100         default:
 101                 return __cmpxchg_local_generic(ptr, old, new_, size);
 102         }
 103 }
 104
 105 /*
 106  * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
 107  * them available.
 108  */
 109 #define cmpxchg_local(ptr, o, n)                                        \
 110         ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \
 111                         (unsigned long)(n), sizeof(*(ptr))))
 112 #ifdef CONFIG_64BIT
 113 #define cmpxchg64_local(ptr, o, n)                                      \
 114 ({                                                                      \
 115         BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 116         cmpxchg_local((ptr), (o), (n));                                 \
 117 })
 118 #else
 119 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 120 #endif
 121
 122 #define cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
 123
 124 #endif /* _ASM_PARISC_CMPXCHG_H_ */