include/asm-m68k/processor.h

   1 /*
   2  * include/asm-m68k/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 <asm/segment.h>
  17 #include <asm/fpu.h>
  18
  19 /*
  20  * User space process size: 3.75GB. This is hardcoded into a few places,
  21  * so don't change it unless you know what you are doing.
  22  */
  23 #define TASK_SIZE       (0xF0000000UL)
  24
  25 /* This decides where the kernel will search for a free chunk of vm
  26  * space during mmap's.
  27  */
  28 #define TASK_UNMAPPED_BASE      0xC0000000UL
  29 #define TASK_UNMAPPED_ALIGN(addr, off)  PAGE_ALIGN(addr)
  30
  31 /*
  32  * Bus types
  33  */
  34 #define EISA_bus 0
  35 #define MCA_bus 0
  36
  37 /*
  38  * if you change this structure, you must change the code and offsets
  39  * in m68k/machasm.S
  40  */
  41
  42 struct thread_struct {
  43         unsigned long  ksp;             /* kernel stack pointer */
  44         unsigned long  usp;             /* user stack pointer */
  45         unsigned short sr;              /* saved status register */
  46         unsigned short fs;              /* saved fs (sfc, dfc) */
  47         unsigned long  crp[2];          /* cpu root pointer */
  48         unsigned long  esp0;            /* points to SR of stack frame */
  49         unsigned long  fp[8*3];
  50         unsigned long  fpcntl[3];       /* fp control regs */
  51         unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
  52 };
  53
  54 #define INIT_MMAP { &init_mm, 0, 0x40000000, NULL, __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED), VM_READ | VM_WRITE | VM_EXEC, 1, NULL, NULL }
  55
  56 #define INIT_TSS  { \
  57         sizeof(init_stack) + (unsigned long) init_stack, 0, \
  58         PS_S, __KERNEL_DS, \
  59         {0, 0}, 0, {0,}, {0, 0, 0}, {0,}, \
  60 }
  61
  62 /*
  63  * Do necessary setup to start up a newly executed thread.
  64  */
  65 static inline void start_thread(struct pt_regs * regs, unsigned long pc,
  66                                 unsigned long usp)
  67 {
  68         /* reads from user space */
  69         set_fs(USER_DS);
  70
  71         regs->pc = pc;
  72         regs->sr &= ~0x2000;
  73         wrusp(usp);
  74 }
  75
  76 /* Free all resources held by a thread. */
  77 static inline void release_thread(struct task_struct *dead_task)
  78 {
  79 }
  80
  81 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
  82
  83 #define copy_segments(nr, tsk, mm)      do { } while (0)
  84 #define release_segments(mm)            do { } while (0)
  85 #define forget_segments()               do { } while (0)
  86
  87 /*
  88  * Free current thread data structures etc..
  89  */
  90 static inline void exit_thread(void)
  91 {
  92 }
  93
  94 /*
  95  * Return saved PC of a blocked thread.
  96  */
  97 extern inline unsigned long thread_saved_pc(struct thread_struct *t)
  98 {
  99         extern void scheduling_functions_start_here(void);
 100         extern void scheduling_functions_end_here(void);
 101         struct switch_stack *sw = (struct switch_stack *)t->ksp;
 102         /* Check whether the thread is blocked in resume() */
 103         if (sw->retpc > (unsigned long)scheduling_functions_start_here &&
 104             sw->retpc < (unsigned long)scheduling_functions_end_here)
 105                 return ((unsigned long *)sw->a6)[1];
 106         else
 107                 return sw->retpc;
 108 }
 109
 110 /* Allocation and freeing of basic task resources. */
 111 #define alloc_task_struct() \
 112         ((struct task_struct *) __get_free_pages(GFP_KERNEL,1))
 113 #define free_task_struct(p)     free_pages((unsigned long)(p),1)
 114
 115 #define init_task       (init_task_union.task)
 116 #define init_stack      (init_task_union.stack)
 117
 118 #endif