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/types.h>
  13
  14 #include <asm/ptrace.h>
  15 #include <asm/sysreg.h>
  16
  17 #define xchg(ptr,x) \
  18         ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
  19
  20 #define nop() asm volatile("nop")
  21
  22 #define mb()                    asm volatile("" : : : "memory")
  23 #define rmb()                   mb()
  24 #define wmb()                   asm volatile("sync 0" : : : "memory")
  25 #define read_barrier_depends()  do { } while(0)
  26 #define set_mb(var, value)      do { var = value; mb(); } while(0)
  27
  28 /*
  29  * Help PathFinder and other Nexus-compliant debuggers keep track of
  30  * the current PID by emitting an Ownership Trace Message each time we
  31  * switch task.
  32  */
  33 #ifdef CONFIG_OWNERSHIP_TRACE
  34 #include <asm/ocd.h>
  35 #define finish_arch_switch(prev)                        \
  36         do {                                            \
  37                 __mtdr(DBGREG_PID, prev->pid);          \
  38                 __mtdr(DBGREG_PID, current->pid);       \
  39         } while(0)
  40 #endif
  41
  42 /*
  43  * switch_to(prev, next, last) should switch from task `prev' to task
  44  * `next'. `prev' will never be the same as `next'.
  45  *
  46  * We just delegate everything to the __switch_to assembly function,
  47  * which is implemented in arch/avr32/kernel/switch_to.S
  48  *
  49  * mb() tells GCC not to cache `current' across this call.
  50  */
  51 struct cpu_context;
  52 struct task_struct;
  53 extern struct task_struct *__switch_to(struct task_struct *,
  54                                        struct cpu_context *,
  55                                        struct cpu_context *);
  56 #define switch_to(prev, next, last)                                     \
  57         do {                                                            \
  58                 last = __switch_to(prev, &prev->thread.cpu_context + 1, \
  59                                    &next->thread.cpu_context);          \
  60         } while (0)
  61
  62 #ifdef CONFIG_SMP
  63 # error "The AVR32 port does not support SMP"
  64 #else
  65 # define smp_mb()               barrier()
  66 # define smp_rmb()              barrier()
  67 # define smp_wmb()              barrier()
  68 # define smp_read_barrier_depends() do { } while(0)
  69 #endif
  70
  71 #include <linux/irqflags.h>
  72
  73 extern void __xchg_called_with_bad_pointer(void);
  74
  75 #ifdef __CHECKER__
  76 extern unsigned long __builtin_xchg(void *ptr, unsigned long x);
  77 #endif
  78
  79 #define xchg_u32(val, m) __builtin_xchg((void *)m, val)
  80
  81 static inline unsigned long __xchg(unsigned long x,
  82                                        volatile void *ptr,
  83                                        int size)
  84 {
  85         switch(size) {
  86         case 4:
  87                 return xchg_u32(x, ptr);
  88         default:
  89                 __xchg_called_with_bad_pointer();
  90                 return x;
  91         }
  92 }
  93
  94 static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
  95                                           unsigned long new)
  96 {
  97         __u32 ret;
  98
  99         asm volatile(
 100                 "1:     ssrf    5\n"
 101                 "       ld.w    %[ret], %[m]\n"
 102                 "       cp.w    %[ret], %[old]\n"
 103                 "       brne    2f\n"
 104                 "       stcond  %[m], %[new]\n"
 105                 "       brne    1b\n"
 106                 "2:\n"
 107                 : [ret] "=&r"(ret), [m] "=m"(*m)
 108                 : "m"(m), [old] "ir"(old), [new] "r"(new)
 109                 : "memory", "cc");
 110         return ret;
 111 }
 112
 113 extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
 114         volatile int * m, unsigned long old, unsigned long new);
 115 #define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
 116
 117 /* This function doesn't exist, so you'll get a linker error
 118    if something tries to do an invalid cmpxchg().  */
 119 extern void __cmpxchg_called_with_bad_pointer(void);
 120
 121 #define __HAVE_ARCH_CMPXCHG 1
 122
 123 static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 124                                       unsigned long new, int size)
 125 {
 126         switch (size) {
 127         case 4:
 128                 return __cmpxchg_u32(ptr, old, new);
 129         case 8:
 130                 return __cmpxchg_u64(ptr, old, new);
 131         }
 132
 133         __cmpxchg_called_with_bad_pointer();
 134         return old;
 135 }
 136
 137 #define cmpxchg(ptr, old, new)                                  \
 138         ((typeof(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), \
 139                                    (unsigned long)(new),        \
 140                                    sizeof(*(ptr))))
 141
 142 struct pt_regs;
 143 extern void __die(const char *, struct pt_regs *, unsigned long,
 144                   const char *, const char *, unsigned long);
 145 extern void __die_if_kernel(const char *, struct pt_regs *, unsigned long,
 146                             const char *, const char *, unsigned long);
 147
 148 #define die(msg, regs, err)                                     \
 149         __die(msg, regs, err, __FILE__ ":", __FUNCTION__, __LINE__)
 150 #define die_if_kernel(msg, regs, err)                                   \
 151         __die_if_kernel(msg, regs, err, __FILE__ ":", __FUNCTION__, __LINE__)
 152
 153 #define arch_align_stack(x)     (x)
 154
 155 #endif /* __ASM_AVR32_SYSTEM_H */