1 /* 2 * linux/arch/m68k/kernel/process.c 3 * 4 * Copyright (C) 1995 Hamish Macdonald 5 * 6 * 68060 fixes by Jesper Skov 7 */ 8 9 /* 10 * This file handles the architecture-dependent parts of process handling.. 11 */ 12 13 #include <linux/errno.h> 14 #include <linux/module.h> 15 #include <linux/sched.h> 16 #include <linux/kernel.h> 17 #include <linux/mm.h> 18 #include <linux/slab.h> 19 #include <linux/fs.h> 20 #include <linux/smp.h> 21 #include <linux/stddef.h> 22 #include <linux/unistd.h> 23 #include <linux/ptrace.h> 24 #include <linux/user.h> 25 #include <linux/reboot.h> 26 #include <linux/init_task.h> 27 #include <linux/mqueue.h> 28 #include <linux/rcupdate.h> 29 30 #include <asm/uaccess.h> 31 #include <asm/traps.h> 32 #include <asm/machdep.h> 33 #include <asm/setup.h> 34 #include <asm/pgtable.h> 35 36 37 asmlinkage void ret_from_fork(void); 38 asmlinkage void ret_from_kernel_thread(void); 39 40 41 /* 42 * Return saved PC from a blocked thread 43 */ 44 unsigned long thread_saved_pc(struct task_struct *tsk) 45 { 46 struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp; 47 /* Check whether the thread is blocked in resume() */ 48 if (in_sched_functions(sw->retpc)) 49 return ((unsigned long *)sw->a6)[1]; 50 else 51 return sw->retpc; 52 } 53 54 /* 55 * The idle loop on an m68k.. 56 */ 57 static void default_idle(void) 58 { 59 if (!need_resched()) 60 #if defined(MACH_ATARI_ONLY) 61 /* block out HSYNC on the atari (falcon) */ 62 __asm__("stop #0x2200" : : : "cc"); 63 #else 64 __asm__("stop #0x2000" : : : "cc"); 65 #endif 66 } 67 68 void (*idle)(void) = default_idle; 69 70 /* 71 * The idle thread. There's no useful work to be 72 * done, so just try to conserve power and have a 73 * low exit latency (ie sit in a loop waiting for 74 * somebody to say that they'd like to reschedule) 75 */ 76 void cpu_idle(void) 77 { 78 /* endless idle loop with no priority at all */ 79 while (1) { 80 rcu_idle_enter(); 81 while (!need_resched()) 82 idle(); 83 rcu_idle_exit(); 84 schedule_preempt_disabled(); 85 } 86 } 87 88 void machine_restart(char * __unused) 89 { 90 if (mach_reset) 91 mach_reset(); 92 for (;;); 93 } 94 95 void machine_halt(void) 96 { 97 if (mach_halt) 98 mach_halt(); 99 for (;;); 100 } 101 102 void machine_power_off(void) 103 { 104 if (mach_power_off) 105 mach_power_off(); 106 for (;;); 107 } 108 109 void (*pm_power_off)(void) = machine_power_off; 110 EXPORT_SYMBOL(pm_power_off); 111 112 void show_regs(struct pt_regs * regs) 113 { 114 printk("\n"); 115 printk("Format %02x Vector: %04x PC: %08lx Status: %04x %s\n", 116 regs->format, regs->vector, regs->pc, regs->sr, print_tainted()); 117 printk("ORIG_D0: %08lx D0: %08lx A2: %08lx A1: %08lx\n", 118 regs->orig_d0, regs->d0, regs->a2, regs->a1); 119 printk("A0: %08lx D5: %08lx D4: %08lx\n", 120 regs->a0, regs->d5, regs->d4); 121 printk("D3: %08lx D2: %08lx D1: %08lx\n", 122 regs->d3, regs->d2, regs->d1); 123 if (!(regs->sr & PS_S)) 124 printk("USP: %08lx\n", rdusp()); 125 } 126 127 void flush_thread(void) 128 { 129 current->thread.fs = __USER_DS; 130 #ifdef CONFIG_FPU 131 if (!FPU_IS_EMU) { 132 unsigned long zero = 0; 133 asm volatile("frestore %0": :"m" (zero)); 134 } 135 #endif 136 } 137 138 /* 139 * "m68k_fork()".. By the time we get here, the 140 * non-volatile registers have also been saved on the 141 * stack. We do some ugly pointer stuff here.. (see 142 * also copy_thread) 143 */ 144 145 asmlinkage int m68k_fork(struct pt_regs *regs) 146 { 147 #ifdef CONFIG_MMU 148 return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL); 149 #else 150 return -EINVAL; 151 #endif 152 } 153 154 asmlinkage int m68k_vfork(struct pt_regs *regs) 155 { 156 return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0, 157 NULL, NULL); 158 } 159 160 asmlinkage int m68k_clone(struct pt_regs *regs) 161 { 162 unsigned long clone_flags; 163 unsigned long newsp; 164 int __user *parent_tidptr, *child_tidptr; 165 166 /* syscall2 puts clone_flags in d1 and usp in d2 */ 167 clone_flags = regs->d1; 168 newsp = regs->d2; 169 parent_tidptr = (int __user *)regs->d3; 170 child_tidptr = (int __user *)regs->d4; 171 if (!newsp) 172 newsp = rdusp(); 173 return do_fork(clone_flags, newsp, regs, 0, 174 parent_tidptr, child_tidptr); 175 } 176 177 int copy_thread(unsigned long clone_flags, unsigned long usp, 178 unsigned long arg, 179 struct task_struct * p, struct pt_regs * regs) 180 { 181 struct pt_regs * childregs; 182 struct switch_stack *childstack; 183 184 childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1; 185 childstack = ((struct switch_stack *) childregs) - 1; 186 187 p->thread.usp = usp; 188 p->thread.ksp = (unsigned long)childstack; 189 p->thread.esp0 = (unsigned long)childregs; 190 191 /* 192 * Must save the current SFC/DFC value, NOT the value when 193 * the parent was last descheduled - RGH 10-08-96 194 */ 195 p->thread.fs = get_fs().seg; 196 197 if (unlikely(!regs)) { 198 /* kernel thread */ 199 memset(childstack, 0, 200 sizeof(struct switch_stack) + sizeof(struct pt_regs)); 201 childregs->sr = PS_S; 202 childstack->a3 = usp; /* function */ 203 childstack->d7 = arg; 204 childstack->retpc = (unsigned long)ret_from_kernel_thread; 205 p->thread.usp = 0; 206 return 0; 207 } 208 *childregs = *regs; 209 childregs->d0 = 0; 210 211 *childstack = ((struct switch_stack *) regs)[-1]; 212 childstack->retpc = (unsigned long)ret_from_fork; 213 214 if (clone_flags & CLONE_SETTLS) 215 task_thread_info(p)->tp_value = regs->d5; 216 217 #ifdef CONFIG_FPU 218 if (!FPU_IS_EMU) { 219 /* Copy the current fpu state */ 220 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory"); 221 222 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) { 223 if (CPU_IS_COLDFIRE) { 224 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t" 225 "fmovel %/fpiar,%1\n\t" 226 "fmovel %/fpcr,%2\n\t" 227 "fmovel %/fpsr,%3" 228 : 229 : "m" (p->thread.fp[0]), 230 "m" (p->thread.fpcntl[0]), 231 "m" (p->thread.fpcntl[1]), 232 "m" (p->thread.fpcntl[2]) 233 : "memory"); 234 } else { 235 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t" 236 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1" 237 : 238 : "m" (p->thread.fp[0]), 239 "m" (p->thread.fpcntl[0]) 240 : "memory"); 241 } 242 } 243 244 /* Restore the state in case the fpu was busy */ 245 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0])); 246 } 247 #endif /* CONFIG_FPU */ 248 249 return 0; 250 } 251 252 /* Fill in the fpu structure for a core dump. */ 253 #ifdef CONFIG_FPU 254 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu) 255 { 256 char fpustate[216]; 257 258 if (FPU_IS_EMU) { 259 int i; 260 261 memcpy(fpu->fpcntl, current->thread.fpcntl, 12); 262 memcpy(fpu->fpregs, current->thread.fp, 96); 263 /* Convert internal fpu reg representation 264 * into long double format 265 */ 266 for (i = 0; i < 24; i += 3) 267 fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) | 268 ((fpu->fpregs[i] & 0x0000ffff) << 16); 269 return 1; 270 } 271 272 /* First dump the fpu context to avoid protocol violation. */ 273 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory"); 274 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2]) 275 return 0; 276 277 if (CPU_IS_COLDFIRE) { 278 asm volatile ("fmovel %/fpiar,%0\n\t" 279 "fmovel %/fpcr,%1\n\t" 280 "fmovel %/fpsr,%2\n\t" 281 "fmovemd %/fp0-%/fp7,%3" 282 : 283 : "m" (fpu->fpcntl[0]), 284 "m" (fpu->fpcntl[1]), 285 "m" (fpu->fpcntl[2]), 286 "m" (fpu->fpregs[0]) 287 : "memory"); 288 } else { 289 asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0" 290 : 291 : "m" (fpu->fpcntl[0]) 292 : "memory"); 293 asm volatile ("fmovemx %/fp0-%/fp7,%0" 294 : 295 : "m" (fpu->fpregs[0]) 296 : "memory"); 297 } 298 299 return 1; 300 } 301 EXPORT_SYMBOL(dump_fpu); 302 #endif /* CONFIG_FPU */ 303 304 unsigned long get_wchan(struct task_struct *p) 305 { 306 unsigned long fp, pc; 307 unsigned long stack_page; 308 int count = 0; 309 if (!p || p == current || p->state == TASK_RUNNING) 310 return 0; 311 312 stack_page = (unsigned long)task_stack_page(p); 313 fp = ((struct switch_stack *)p->thread.ksp)->a6; 314 do { 315 if (fp < stack_page+sizeof(struct thread_info) || 316 fp >= 8184+stack_page) 317 return 0; 318 pc = ((unsigned long *)fp)[1]; 319 if (!in_sched_functions(pc)) 320 return pc; 321 fp = *(unsigned long *) fp; 322 } while (count++ < 16); 323 return 0; 324 } 325