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_SW_A7
  24         extern unsigned int sw_usp;
  25         return sw_usp;
  26 #else
  27         register unsigned long usp __asm__("a0");
  28         /* move %usp,%a0 */
  29         __asm__ __volatile__(".word 0x4e68" : "=a" (usp));
  30         return usp;
  31 #endif
  32 }
  33
  34 static inline void wrusp(unsigned long usp)
  35 {
  36 #ifdef CONFIG_COLDFIRE_SW_A7
  37         extern unsigned int sw_usp;
  38         sw_usp = usp;
  39 #else
  40         register unsigned long a0 __asm__("a0") = usp;
  41         /* move %a0,%usp */
  42         __asm__ __volatile__(".word 0x4e60" : : "a" (a0) );
  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 #ifdef CONFIG_MMU
  51 #ifndef CONFIG_SUN3
  52 #define TASK_SIZE       (0xF0000000UL)
  53 #else
  54 #define TASK_SIZE       (0x0E000000UL)
  55 #endif
  56 #else
  57 #define TASK_SIZE       (0xFFFFFFFFUL)
  58 #endif
  59
  60 #ifdef __KERNEL__
  61 #define STACK_TOP       TASK_SIZE
  62 #define STACK_TOP_MAX   STACK_TOP
  63 #endif
  64
  65 /* This decides where the kernel will search for a free chunk of vm
  66  * space during mmap's.
  67  */
  68 #ifdef CONFIG_MMU
  69 #ifndef CONFIG_SUN3
  70 #define TASK_UNMAPPED_BASE      0xC0000000UL
  71 #else
  72 #define TASK_UNMAPPED_BASE      0x0A000000UL
  73 #endif
  74 #define TASK_UNMAPPED_ALIGN(addr, off)  PAGE_ALIGN(addr)
  75 #else
  76 #define TASK_UNMAPPED_BASE      0
  77 #endif
  78
  79 struct thread_struct {
  80         unsigned long  ksp;             /* kernel stack pointer */
  81         unsigned long  usp;             /* user stack pointer */
  82         unsigned short sr;              /* saved status register */
  83         unsigned short fs;              /* saved fs (sfc, dfc) */
  84         unsigned long  crp[2];          /* cpu root pointer */
  85         unsigned long  esp0;            /* points to SR of stack frame */
  86         unsigned long  faddr;           /* info about last fault */
  87         int            signo, code;
  88         unsigned long  fp[8*3];
  89         unsigned long  fpcntl[3];       /* fp control regs */
  90         unsigned char  fpstate[FPSTATESIZE];  /* floating point state */
  91         struct thread_info info;
  92 };
  93
  94 #define INIT_THREAD  {                                                  \
  95         .ksp    = sizeof(init_stack) + (unsigned long) init_stack,      \
  96         .sr     = PS_S,                                                 \
  97         .fs     = __KERNEL_DS,                                          \
  98         .info   = INIT_THREAD_INFO(init_task),                          \
  99 }
 100
 101 #ifdef CONFIG_MMU
 102 /*
 103  * Do necessary setup to start up a newly executed thread.
 104  */
 105 static inline void start_thread(struct pt_regs * regs, unsigned long pc,
 106                                 unsigned long usp)
 107 {
 108         /* reads from user space */
 109         set_fs(USER_DS);
 110
 111         regs->pc = pc;
 112         regs->sr &= ~0x2000;
 113         wrusp(usp);
 114 }
 115
 116 extern int handle_kernel_fault(struct pt_regs *regs);
 117
 118 #else
 119
 120 /*
 121  * Coldfire stacks need to be re-aligned on trap exit, conventional
 122  * 68k can handle this case cleanly.
 123  */
 124 #ifdef CONFIG_COLDFIRE
 125 #define reformat(_regs)         do { (_regs)->format = 0x4; } while(0)
 126 #else
 127 #define reformat(_regs)         do { } while (0)
 128 #endif
 129
 130 #define start_thread(_regs, _pc, _usp)                  \
 131 do {                                                    \
 132         set_fs(USER_DS); /* reads from user space */    \
 133         (_regs)->pc = (_pc);                            \
 134         ((struct switch_stack *)(_regs))[-1].a6 = 0;    \
 135         reformat(_regs);                                \
 136         if (current->mm)                                \
 137                 (_regs)->d5 = current->mm->start_data;  \
 138         (_regs)->sr &= ~0x2000;                         \
 139         wrusp(_usp);                                    \
 140 } while(0)
 141
 142 #endif
 143
 144 /* Forward declaration, a strange C thing */
 145 struct task_struct;
 146
 147 /* Free all resources held by a thread. */
 148 static inline void release_thread(struct task_struct *dead_task)
 149 {
 150 }
 151
 152 /* Prepare to copy thread state - unlazy all lazy status */
 153 #define prepare_to_copy(tsk)    do { } while (0)
 154
 155 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 156
 157 /*
 158  * Free current thread data structures etc..
 159  */
 160 static inline void exit_thread(void)
 161 {
 162 }
 163
 164 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 165
 166 unsigned long get_wchan(struct task_struct *p);
 167
 168 #define KSTK_EIP(tsk)   \
 169     ({                  \
 170         unsigned long eip = 0;   \
 171         if ((tsk)->thread.esp0 > PAGE_SIZE && \
 172             (virt_addr_valid((tsk)->thread.esp0))) \
 173               eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \
 174         eip; })
 175 #define KSTK_ESP(tsk)   ((tsk) == current ? rdusp() : (tsk)->thread.usp)
 176
 177 #define task_pt_regs(tsk)       ((struct pt_regs *) ((tsk)->thread.esp0))
 178
 179 #define cpu_relax()     barrier()
 180
 181 #endif