include/asm-avr32/system.h

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #ifndef __ASM_AVR32_SYSTEM_H
   9 #define __ASM_AVR32_SYSTEM_H
  10
  11 #include <linux/compiler.h>
  12 #include <linux/linkage.h>
  13 #include <linux/types.h>
  14
  15 #include <asm/ptrace.h>
  16 #include <asm/sysreg.h>
  17
  18 #define xchg(ptr,x) \
  19         ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  20
  21 #define nop() asm volatile("nop")
  22
  23 #define mb()                    asm volatile("" : : : "memory")
  24 #define rmb()                   mb()
  25 #define wmb()                   asm volatile("sync 0" : : : "memory")
  26 #define read_barrier_depends()  do { } while(0)
  27 #define set_mb(var, value)      do { var = value; mb(); } while(0)
  28
  29 /*
  30  * Help PathFinder and other Nexus-compliant debuggers keep track of
  31  * the current PID by emitting an Ownership Trace Message each time we
  32  * switch task.
  33  */
  34 #ifdef CONFIG_OWNERSHIP_TRACE
  35 #include <asm/ocd.h>
  36 #define finish_arch_switch(prev)                        \
  37         do {                                            \
  38                 __mtdr(DBGREG_PID, prev->pid);          \
  39                 __mtdr(DBGREG_PID, current->pid);       \
  40         } while(0)
  41 #endif
  42
  43 /*
  44  * switch_to(prev, next, last) should switch from task `prev' to task
  45  * `next'. `prev' will never be the same as `next'.
  46  *
  47  * We just delegate everything to the __switch_to assembly function,
  48  * which is implemented in arch/avr32/kernel/switch_to.S
  49  *
  50  * mb() tells GCC not to cache `current' across this call.
  51  */
  52 struct cpu_context;
  53 struct task_struct;
  54 extern struct task_struct *__switch_to(struct task_struct *,
  55                                        struct cpu_context *,
  56                                        struct cpu_context *);
  57 #define switch_to(prev, next, last)                                     \
  58         do {                                                            \
  59                 last = __switch_to(prev, &prev->thread.cpu_context + 1, \
  60                                    &next->thread.cpu_context);          \
  61         } while (0)
  62
  63 #ifdef CONFIG_SMP
  64 # error "The AVR32 port does not support SMP"
  65 #else
  66 # define smp_mb()               barrier()
  67 # define smp_rmb()              barrier()
  68 # define smp_wmb()              barrier()
  69 # define smp_read_barrier_depends() do { } while(0)
  70 #endif
  71
  72 #include <linux/irqflags.h>
  73
  74 extern void __xchg_called_with_bad_pointer(void);
  75
  76 #ifdef __CHECKER__
  77 extern unsigned long __builtin_xchg(void *ptr, unsigned long x);
  78 #endif
  79
  80 #define xchg_u32(val, m) __builtin_xchg((void *)m, val)
  81
  82 static inline unsigned long __xchg(unsigned long x,
  83                                        volatile void *ptr,
  84                                        int size)
  85 {
  86         switch(size) {
  87         case 4:
  88                 return xchg_u32(x, ptr);
  89         default:
  90                 __xchg_called_with_bad_pointer();
  91                 return x;
  92         }
  93 }
  94
  95 static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
  96                                           unsigned long new)
  97 {
  98         __u32 ret;
  99
 100         asm volatile(
 101                 "1:     ssrf    5\n"
 102                 "       ld.w    %[ret], %[m]\n"
 103                 "       cp.w    %[ret], %[old]\n"
 104                 "       brne    2f\n"
 105                 "       stcond  %[m], %[new]\n"
 106                 "       brne    1b\n"
 107                 "2:\n"
 108                 : [ret] "=&r"(ret), [m] "=m"(*m)
 109                 : "m"(m), [old] "ir"(old), [new] "r"(new)
 110                 : "memory", "cc");
 111         return ret;
 112 }
 113
 114 extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
 115         volatile int * m, unsigned long old, unsigned long new);
 116 #define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
 117
 118 /* This function doesn't exist, so you'll get a linker error
 119    if something tries to do an invalid cmpxchg().  */
 120 extern void __cmpxchg_called_with_bad_pointer(void);
 121
 122 #define __HAVE_ARCH_CMPXCHG 1
 123
 124 static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 125                                       unsigned long new, int size)
 126 {
 127         switch (size) {
 128         case 4:
 129                 return __cmpxchg_u32(ptr, old, new);
 130         case 8:
 131                 return __cmpxchg_u64(ptr, old, new);
 132         }
 133
 134         __cmpxchg_called_with_bad_pointer();
 135         return old;
 136 }
 137
 138 #define cmpxchg(ptr, old, new)                                  \
 139         ((typeof(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), \
 140                                    (unsigned long)(new),        \
 141                                    sizeof(*(ptr))))
 142
 143 struct pt_regs;
 144 void NORET_TYPE die(const char *str, struct pt_regs *regs, long err);
 145 void _exception(long signr, struct pt_regs *regs, int code,
 146                 unsigned long addr);
 147
 148 #define arch_align_stack(x)     (x)
 149
 150 #endif /* __ASM_AVR32_SYSTEM_H */