arch/openrisc/include/asm/cmpxchg.h

   1 /*
   2  * Copyright (C) 2014 Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
   3  *
   4  * This file is licensed under the terms of the GNU General Public License
   5  * version 2.  This program is licensed "as is" without any warranty of any
   6  * kind, whether express or implied.
   7  */
   8
   9 #ifndef __ASM_OPENRISC_CMPXCHG_H
  10 #define __ASM_OPENRISC_CMPXCHG_H
  11
  12 #include  <linux/types.h>
  13
  14 /*
  15  * This function doesn't exist, so you'll get a linker error
  16  * if something tries to do an invalid cmpxchg().
  17  */
  18 extern void __cmpxchg_called_with_bad_pointer(void);
  19
  20 #define __HAVE_ARCH_CMPXCHG 1
  21
  22 static inline unsigned long
  23 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
  24 {
  25         if (size != 4) {
  26                 __cmpxchg_called_with_bad_pointer();
  27                 return old;
  28         }
  29
  30         __asm__ __volatile__(
  31                 "1:     l.lwa %0, 0(%1)         \n"
  32                 "       l.sfeq %0, %2           \n"
  33                 "       l.bnf 2f                \n"
  34                 "        l.nop                  \n"
  35                 "       l.swa 0(%1), %3         \n"
  36                 "       l.bnf 1b                \n"
  37                 "        l.nop                  \n"
  38                 "2:                             \n"
  39                 : "=&r"(old)
  40                 : "r"(ptr), "r"(old), "r"(new)
  41                 : "cc", "memory");
  42
  43         return old;
  44 }
  45
  46 #define cmpxchg(ptr, o, n)                                              \
  47         ({                                                              \
  48                 (__typeof__(*(ptr))) __cmpxchg((ptr),                   \
  49                                                (unsigned long)(o),      \
  50                                                (unsigned long)(n),      \
  51                                                sizeof(*(ptr)));         \
  52         })
  53
  54 /*
  55  * This function doesn't exist, so you'll get a linker error if
  56  * something tries to do an invalidly-sized xchg().
  57  */
  58 extern void __xchg_called_with_bad_pointer(void);
  59
  60 static inline unsigned long __xchg(unsigned long val, volatile void *ptr,
  61                                    int size)
  62 {
  63         if (size != 4) {
  64                 __xchg_called_with_bad_pointer();
  65                 return val;
  66         }
  67
  68         __asm__ __volatile__(
  69                 "1:     l.lwa %0, 0(%1)         \n"
  70                 "       l.swa 0(%1), %2         \n"
  71                 "       l.bnf 1b                \n"
  72                 "        l.nop                  \n"
  73                 : "=&r"(val)
  74                 : "r"(ptr), "r"(val)
  75                 : "cc", "memory");
  76
  77         return val;
  78 }
  79
  80 #define xchg(ptr, with)                                                 \
  81         ({                                                              \
  82                 (__typeof__(*(ptr))) __xchg((unsigned long)(with),      \
  83                                             (ptr),                      \
  84                                             sizeof(*(ptr)));            \
  85         })
  86
  87 #endif /* __ASM_OPENRISC_CMPXCHG_H */