LXR linux/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*/
  14extern void __xchg_called_with_bad_pointer(void);
  15
  16/* __xchg32/64 defined in arch/parisc/lib/bitops.c */
  17extern unsigned long __xchg8(char, volatile char *);
  18extern unsigned long __xchg32(int, volatile int *);
  19#ifdef CONFIG_64BIT
  20extern unsigned long __xchg64(unsigned long, volatile unsigned long *);
  21#endif
  22
  23/* optimizer better get rid of switch since size is a constant */
  24static 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 arch_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 */
  57extern void __cmpxchg_called_with_bad_pointer(void);
  58
  59/* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */
  60extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old,
  61                                   unsigned int new_);
  62extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_);
  63extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_);
  64
  65/* don't worry...optimizer will get rid of most of this */
  66static 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, old & 0xff, new_ & 0xff);
  76        }
  77        __cmpxchg_called_with_bad_pointer();
  78        return old;
  79}
  80
  81#define arch_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
  91static 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 __generic_cmpxchg_local(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 arch_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 arch_cmpxchg64_local(ptr, o, n)                                 \
 114({                                                                      \
 115        BUILD_BUG_ON(sizeof(*(ptr)) != 8);                              \
 116        cmpxchg_local((ptr), (o), (n));                                 \
 117})
 118#else
 119#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))
 120#endif
 121
 122#define arch_cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n)
 123
 124#endif /* _ASM_PARISC_CMPXCHG_H_ */
 125