LXR linux/arch/avr32/include/asm/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                ocd_write(PID, prev->pid);              \
  39                ocd_write(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 */
  52struct cpu_context;
  53struct task_struct;
  54extern 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
  74extern void __xchg_called_with_bad_pointer(void);
  75
  76static inline unsigned long xchg_u32(u32 val, volatile u32 *m)
  77{
  78        u32 ret;
  79
  80        asm volatile("xchg %[ret], %[m], %[val]"
  81                        : [ret] "=&r"(ret), "=m"(*m)
  82                        : "m"(*m), [m] "r"(m), [val] "r"(val)
  83                        : "memory");
  84        return ret;
  85}
  86
  87static inline unsigned long __xchg(unsigned long x,
  88                                       volatile void *ptr,
  89                                       int size)
  90{
  91        switch(size) {
  92        case 4:
  93                return xchg_u32(x, ptr);
  94        default:
  95                __xchg_called_with_bad_pointer();
  96                return x;
  97        }
  98}
  99
 100static inline unsigned long __cmpxchg_u32(volatile int *m, unsigned long old,
 101                                          unsigned long new)
 102{
 103        __u32 ret;
 104
 105        asm volatile(
 106                "1:     ssrf    5\n"
 107                "       ld.w    %[ret], %[m]\n"
 108                "       cp.w    %[ret], %[old]\n"
 109                "       brne    2f\n"
 110                "       stcond  %[m], %[new]\n"
 111                "       brne    1b\n"
 112                "2:\n"
 113                : [ret] "=&r"(ret), [m] "=m"(*m)
 114                : "m"(m), [old] "ir"(old), [new] "r"(new)
 115                : "memory", "cc");
 116        return ret;
 117}
 118
 119extern unsigned long __cmpxchg_u64_unsupported_on_32bit_kernels(
 120        volatile int * m, unsigned long old, unsigned long new);
 121#define __cmpxchg_u64 __cmpxchg_u64_unsupported_on_32bit_kernels
 122
 123/* This function doesn't exist, so you'll get a linker error
 124   if something tries to do an invalid cmpxchg().  */
 125extern void __cmpxchg_called_with_bad_pointer(void);
 126
 127#define __HAVE_ARCH_CMPXCHG 1
 128
 129static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 130                                      unsigned long new, int size)
 131{
 132        switch (size) {
 133        case 4:
 134                return __cmpxchg_u32(ptr, old, new);
 135        case 8:
 136                return __cmpxchg_u64(ptr, old, new);
 137        }
 138
 139        __cmpxchg_called_with_bad_pointer();
 140        return old;
 141}
 142
 143#define cmpxchg(ptr, old, new)                                  \
 144        ((typeof(*(ptr)))__cmpxchg((ptr), (unsigned long)(old), \
 145                                   (unsigned long)(new),        \
 146                                   sizeof(*(ptr))))
 147
 148#include <asm-generic/cmpxchg-local.h>
 149
 150static inline unsigned long __cmpxchg_local(volatile void *ptr,
 151                                      unsigned long old,
 152                                      unsigned long new, int size)
 153{
 154        switch (size) {
 155        case 4:
 156                return __cmpxchg_u32(ptr, old, new);
 157        default:
 158                return __cmpxchg_local_generic(ptr, old, new, size);
 159        }
 160
 161        return old;
 162}
 163
 164#define cmpxchg_local(ptr, old, new)                                    \
 165        ((typeof(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(old),   \
 166                                   (unsigned long)(new),                \
 167                                   sizeof(*(ptr))))
 168
 169#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
 170
 171struct pt_regs;
 172void NORET_TYPE die(const char *str, struct pt_regs *regs, long err);
 173void _exception(long signr, struct pt_regs *regs, int code,
 174                unsigned long addr);
 175
 176#define arch_align_stack(x)     (x)
 177
 178#endif /* __ASM_AVR32_SYSTEM_H */
 179