include/asm-m68knommu/processor.h

   1 /*
   2  * include/asm-m68knommu/processor.h
   3  *
   4  * Copyright (C) 1995 Hamish Macdonald
   5  */
   6
   7 #ifndef __ASM_M68K_PROCESSOR_H
   8 #define __ASM_M68K_PROCESSOR_H
   9
  10 /*
  11  * Default implementation of macro that returns current
  12  * instruction pointer ("program counter").
  13  */
  14 #define current_text_addr() ({ __label__ _l; _l: &&_l;})
  15
  16 #include <linux/compiler.h>
  17 #include <linux/threads.h>
  18 #include <asm/types.h>
  19 #include <asm/segment.h>
  20 #include <asm/fpu.h>
  21 #include <asm/ptrace.h>
  22 #include <asm/current.h>
  23
  24 static inline unsigned long rdusp(void)
  25 {
  26 #ifdef CONFIG_COLDFIRE
  27         extern unsigned int sw_usp;
  28         return(sw_usp);
  29 #else
  30         unsigned long usp;
  31         __asm__ __volatile__("move %/usp,%0" : "=a" (usp));
  32         return usp;
  33 #endif
  34 }
  35
  36 static inline void wrusp(unsigned long usp)
  37 {
  38 #ifdef CONFIG_COLDFIRE
  39         extern unsigned int sw_usp;
  40         sw_usp = usp;
  41 #else
  42         __asm__ __volatile__("move %0,%/usp" : : "a" (usp));
  43 #endif
  44 }
  45
  46 /*
  47  * User space process size: 3.75GB. This is hardcoded into a few places,
  48  * so don't change it unless you know what you are doing.
  49  */
  50 #define TASK_SIZE       (0xF0000000UL)
  51
  52 /*
  53  * This decides where the kernel will search for a free chunk of vm
  54  * space during mmap's. We won't be using it
  55  */
  56 #define TASK_UNMAPPED_BASE      0
  57
  58 /*
  59  * if you change this structure, you must change the code and offsets
  60  * in m68k/machasm.S
  61  */
  62
  63 struct thread_struct {
  64         unsigned long  ksp;             /* kernel stack pointer */
  65         unsigned long  usp;             /* user stack pointer */
  66         unsigned short sr;              /* saved status register */
  67         unsigned short fs;              /* saved fs (sfc, dfc) */
  68         unsigned long  crp[2];          /* cpu root pointer */
  69         unsigned long  esp0;            /* points to SR of stack frame */
  70         unsigned long  fp[8*3];
  71         unsigned long  fpcntl[3];       /* fp control regs */
  72         unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
  73 };
  74
  75 #define INIT_THREAD  { \
  76         sizeof(init_stack) + (unsigned long) init_stack, 0, \
  77         PS_S, __KERNEL_DS, \
  78         {0, 0}, 0, {0,}, {0, 0, 0}, {0,}, \
  79 }
  80
  81 /*
  82  * Coldfire stacks need to be re-aligned on trap exit, conventional
  83  * 68k can handle this case cleanly.
  84  */
  85 #if defined(CONFIG_COLDFIRE)
  86 #define reformat(_regs)         do { (_regs)->format = 0x4; } while(0)
  87 #else
  88 #define reformat(_regs)         do { } while (0)
  89 #endif
  90
  91 /*
  92  * Do necessary setup to start up a newly executed thread.
  93  *
  94  * pass the data segment into user programs if it exists,
  95  * it can't hurt anything as far as I can tell
  96  */
  97 #define start_thread(_regs, _pc, _usp)                  \
  98 do {                                                    \
  99         set_fs(USER_DS); /* reads from user space */    \
 100         (_regs)->pc = (_pc);                            \
 101         ((struct switch_stack *)(_regs))[-1].a6 = 0;    \
 102         reformat(_regs);                                \
 103         if (current->mm)                                \
 104                 (_regs)->d5 = current->mm->start_data;  \
 105         (_regs)->sr &= ~0x2000;                         \
 106         wrusp(_usp);                                    \
 107 } while(0)
 108
 109 /* Forward declaration, a strange C thing */
 110 struct task_struct;
 111
 112 /* Free all resources held by a thread. */
 113 static inline void release_thread(struct task_struct *dead_task)
 114 {
 115 }
 116
 117 /* Prepare to copy thread state - unlazy all lazy status */
 118 #define prepare_to_copy(tsk)    do { } while (0)
 119
 120 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 121
 122 /*
 123  * Free current thread data structures etc..
 124  */
 125 static inline void exit_thread(void)
 126 {
 127 }
 128
 129 unsigned long thread_saved_pc(struct task_struct *tsk);
 130 unsigned long get_wchan(struct task_struct *p);
 131
 132 #define KSTK_EIP(tsk)   \
 133     ({                  \
 134         unsigned long eip = 0;   \
 135         if ((tsk)->thread.esp0 > PAGE_SIZE && \
 136             (virt_addr_valid((tsk)->thread.esp0))) \
 137               eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
 138         eip; })
 139 #define KSTK_ESP(tsk)   ((tsk) == current ? rdusp() : (tsk)->thread.usp)
 140
 141 #define cpu_relax()    barrier()
 142
 143 #endif