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 regs->pc = pc; 109 regs->sr &= ~0x2000; 110 wrusp(usp); 111 } 112 113 extern int handle_kernel_fault(struct pt_regs *regs); 114 115 #else 116 117 /* 118 * Coldfire stacks need to be re-aligned on trap exit, conventional 119 * 68k can handle this case cleanly. 120 */ 121 #ifdef CONFIG_COLDFIRE 122 #define reformat(_regs) do { (_regs)->format = 0x4; } while(0) 123 #else 124 #define reformat(_regs) do { } while (0) 125 #endif 126 127 #define start_thread(_regs, _pc, _usp) \ 128 do { \ 129 (_regs)->pc = (_pc); \ 130 ((struct switch_stack *)(_regs))[-1].a6 = 0; \ 131 reformat(_regs); \ 132 if (current->mm) \ 133 (_regs)->d5 = current->mm->start_data; \ 134 (_regs)->sr &= ~0x2000; \ 135 wrusp(_usp); \ 136 } while(0) 137 138 #endif 139 140 /* Forward declaration, a strange C thing */ 141 struct task_struct; 142 143 /* Free all resources held by a thread. */ 144 static inline void release_thread(struct task_struct *dead_task) 145 { 146 } 147 148 /* Prepare to copy thread state - unlazy all lazy status */ 149 #define prepare_to_copy(tsk) do { } while (0) 150 151 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags); 152 153 /* 154 * Free current thread data structures etc.. 155 */ 156 static inline void exit_thread(void) 157 { 158 } 159 160 extern unsigned long thread_saved_pc(struct task_struct *tsk); 161 162 unsigned long get_wchan(struct task_struct *p); 163 164 #define KSTK_EIP(tsk) \ 165 ({ \ 166 unsigned long eip = 0; \ 167 if ((tsk)->thread.esp0 > PAGE_SIZE && \ 168 (virt_addr_valid((tsk)->thread.esp0))) \ 169 eip = ((struct pt_regs *) (tsk)->thread.esp0)->pc; \ 170 eip; }) 171 #define KSTK_ESP(tsk) ((tsk) == current ? rdusp() : (tsk)->thread.usp) 172 173 #define task_pt_regs(tsk) ((struct pt_regs *) ((tsk)->thread.esp0)) 174 175 #define cpu_relax() barrier() 176 177 #endif 178