arch/m68k/include/asm/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 <linux/thread_info.h>
  17 #include <asm/segment.h>
  18 #include <asm/fpu.h>
  19 #include <asm/ptrace.h>
  20
  21 static inline unsigned long rdusp(void)
  22 {
  23 #ifdef CONFIG_COLDFIRE
  24         extern unsigned int sw_usp;
  25         return sw_usp;
  26 #else
  27         unsigned long usp;
  28         __asm__ __volatile__("move %/usp,%0" : "=a" (usp));
  29         return usp;
  30 #endif
  31 }
  32
  33 static inline void wrusp(unsigned long usp)
  34 {
  35 #ifdef CONFIG_COLDFIRE
  36         extern unsigned int sw_usp;
  37         sw_usp = usp;
  38 #else
  39         __asm__ __volatile__("move %0,%/usp" : : "a" (usp));
  40 #endif
  41 }
  42
  43 /*
  44  * User space process size: 3.75GB. This is hardcoded into a few places,
  45  * so don't change it unless you know what you are doing.
  46  */
  47 #ifndef CONFIG_SUN3
  48 #define TASK_SIZE       (0xF0000000UL)
  49 #else
  50 #define TASK_SIZE       (0x0E000000UL)
  51 #endif
  52
  53 #ifdef __KERNEL__
  54 #define STACK_TOP       TASK_SIZE
  55 #define STACK_TOP_MAX   STACK_TOP
  56 #endif
  57
  58 /* This decides where the kernel will search for a free chunk of vm
  59  * space during mmap's.
  60  */
  61 #ifdef CONFIG_MMU
  62 #ifndef CONFIG_SUN3
  63 #define TASK_UNMAPPED_BASE      0xC0000000UL
  64 #else
  65 #define TASK_UNMAPPED_BASE      0x0A000000UL
  66 #endif
  67 #define TASK_UNMAPPED_ALIGN(addr, off)  PAGE_ALIGN(addr)
  68 #else
  69 #define TASK_UNMAPPED_BASE      0
  70 #endif
  71
  72 struct thread_struct {
  73         unsigned long  ksp;             /* kernel stack pointer */
  74         unsigned long  usp;             /* user stack pointer */
  75         unsigned short sr;              /* saved status register */
  76         unsigned short fs;              /* saved fs (sfc, dfc) */
  77         unsigned long  crp[2];          /* cpu root pointer */
  78         unsigned long  esp0;            /* points to SR of stack frame */
  79         unsigned long  faddr;           /* info about last fault */
  80         int            signo, code;
  81         unsigned long  fp[8*3];
  82         unsigned long  fpcntl[3];       /* fp control regs */
  83         unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
  84         struct thread_info info;
  85 };
  86
  87 #define INIT_THREAD  {                                                  \
  88         .ksp    = sizeof(init_stack) + (unsigned long) init_stack,      \
  89         .sr     = PS_S,                                                 \
  90         .fs     = __KERNEL_DS,                                          \
  91         .info   = INIT_THREAD_INFO(init_task),                          \
  92 }
  93
  94 #ifdef CONFIG_MMU
  95 /*
  96  * Do necessary setup to start up a newly executed thread.
  97  */
  98 static inline void start_thread(struct pt_regs * regs, unsigned long pc,
  99                                 unsigned long usp)
 100 {
 101         /* reads from user space */
 102         set_fs(USER_DS);
 103
 104         regs->pc = pc;
 105         regs->sr &= ~0x2000;
 106         wrusp(usp);
 107 }
 108
 109 #else
 110
 111 /*
 112  * Coldfire stacks need to be re-aligned on trap exit, conventional
 113  * 68k can handle this case cleanly.
 114  */
 115 #ifdef CONFIG_COLDFIRE
 116 #define reformat(_regs)         do { (_regs)->format = 0x4; } while(0)
 117 #else
 118 #define reformat(_regs)         do { } while (0)
 119 #endif
 120
 121 #define start_thread(_regs, _pc, _usp)                  \
 122 do {                                                    \
 123         set_fs(USER_DS); /* reads from user space */    \
 124         (_regs)->pc = (_pc);                            \
 125         ((struct switch_stack *)(_regs))[-1].a6 = 0;    \
 126         reformat(_regs);                                \
 127         if (current->mm)                                \
 128                 (_regs)->d5 = current->mm->start_data;  \
 129         (_regs)->sr &= ~0x2000;                         \
 130         wrusp(_usp);                                    \
 131 } while(0)
 132
 133 #endif
 134
 135 /* Forward declaration, a strange C thing */
 136 struct task_struct;
 137
 138 /* Free all resources held by a thread. */
 139 static inline void release_thread(struct task_struct *dead_task)
 140 {
 141 }
 142
 143 /* Prepare to copy thread state - unlazy all lazy status */
 144 #define prepare_to_copy(tsk)    do { } while (0)
 145
 146 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 147
 148 /*
 149  * Free current thread data structures etc..
 150  */
 151 static inline void exit_thread(void)
 152 {
 153 }
 154
 155 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 156
 157 unsigned long get_wchan(struct task_struct *p);
 158
 159 #define KSTK_EIP(tsk)   \
 160     ({                  \
 161         unsigned long eip = 0;   \
 162         if ((tsk)->thread.esp0 > PAGE_SIZE && \
 163             (virt_addr_valid((tsk)->thread.esp0))) \
 164               eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
 165         eip; })
 166 #define KSTK_ESP(tsk)   ((tsk) == current ? rdusp() : (tsk)->thread.usp)
 167
 168 #define cpu_relax()     barrier()
 169
 170 #endif