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 #include <asm/ptrace.h>
  19
  20 extern inline unsigned long rdusp(void) {
  21         unsigned long usp;
  22
  23         __asm__ __volatile__("move %/usp,%0" : "=a" (usp));
  24         return usp;
  25 }
  26
  27 extern inline void wrusp(unsigned long usp) {
  28         __asm__ __volatile__("move %0,%/usp" : : "a" (usp));
  29 }
  30
  31 /*
  32  * User space process size: 3.75GB. This is hardcoded into a few places,
  33  * so don't change it unless you know what you are doing.
  34  */
  35 #define TASK_SIZE       (0xF0000000UL)
  36
  37 /* This decides where the kernel will search for a free chunk of vm
  38  * space during mmap's.
  39  */
  40 #define TASK_UNMAPPED_BASE      0xC0000000UL
  41 #define TASK_UNMAPPED_ALIGN(addr, off)  PAGE_ALIGN(addr)
  42
  43 /*
  44  * Bus types
  45  */
  46 #define EISA_bus 0
  47 #define MCA_bus 0
  48
  49 /*
  50  * if you change this structure, you must change the code and offsets
  51  * in m68k/machasm.S
  52  */
  53
  54 struct thread_struct {
  55         unsigned long  ksp;             /* kernel stack pointer */
  56         unsigned long  usp;             /* user stack pointer */
  57         unsigned short sr;              /* saved status register */
  58         unsigned short fs;              /* saved fs (sfc, dfc) */
  59         unsigned long  crp[2];          /* cpu root pointer */
  60         unsigned long  esp0;            /* points to SR of stack frame */
  61         unsigned long  fp[8*3];
  62         unsigned long  fpcntl[3];       /* fp control regs */
  63         unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
  64 };
  65
  66 #define INIT_MMAP { &init_mm, 0, 0x40000000, NULL, __pgprot(_PAGE_PRESENT|_PAGE_ACCESSED), VM_READ | VM_WRITE | VM_EXEC, 1, NULL, NULL }
  67
  68 #define INIT_THREAD  { \
  69         sizeof(init_stack) + (unsigned long) init_stack, 0, \
  70         PS_S, __KERNEL_DS, \
  71         {0, 0}, 0, {0,}, {0, 0, 0}, {0,}, \
  72 }
  73
  74 /*
  75  * Do necessary setup to start up a newly executed thread.
  76  */
  77 static inline void start_thread(struct pt_regs * regs, unsigned long pc,
  78                                 unsigned long usp)
  79 {
  80         /* reads from user space */
  81         set_fs(USER_DS);
  82
  83         regs->pc = pc;
  84         regs->sr &= ~0x2000;
  85         wrusp(usp);
  86 }
  87
  88 /* Forward declaration, a strange C thing */
  89 struct task_struct;
  90
  91 /* Free all resources held by a thread. */
  92 static inline void release_thread(struct task_struct *dead_task)
  93 {
  94 }
  95
  96 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
  97
  98 #define copy_segments(tsk, mm)          do { } while (0)
  99 #define release_segments(mm)            do { } while (0)
 100 #define forget_segments()               do { } while (0)
 101
 102 /*
 103  * Free current thread data structures etc..
 104  */
 105 static inline void exit_thread(void)
 106 {
 107 }
 108
 109 /*
 110  * Return saved PC of a blocked thread.
 111  */
 112 extern inline unsigned long thread_saved_pc(struct thread_struct *t)
 113 {
 114         extern void scheduling_functions_start_here(void);
 115         extern void scheduling_functions_end_here(void);
 116         struct switch_stack *sw = (struct switch_stack *)t->ksp;
 117         /* Check whether the thread is blocked in resume() */
 118         if (sw->retpc > (unsigned long)scheduling_functions_start_here &&
 119             sw->retpc < (unsigned long)scheduling_functions_end_here)
 120                 return ((unsigned long *)sw->a6)[1];
 121         else
 122                 return sw->retpc;
 123 }
 124
 125 #define THREAD_SIZE (2*PAGE_SIZE)
 126
 127 /* Allocation and freeing of basic task resources. */
 128 #define alloc_task_struct() \
 129         ((struct task_struct *) __get_free_pages(GFP_KERNEL,1))
 130 #define free_task_struct(p)     free_pages((unsigned long)(p),1)
 131
 132 #define init_task       (init_task_union.task)
 133 #define init_stack      (init_task_union.stack)
 134
 135 #endif