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 * Why not generic sys_clone, you ask? m68k passes all arguments on stack. 140 * And we need all registers saved, which means a bunch of stuff pushed 141 * on top of pt_regs, which means that sys_clone() arguments would be 142 * buried. We could, of course, copy them, but it's too costly for no 143 * good reason - generic clone() would have to copy them *again* for 144 * do_fork() anyway. So in this case it's actually better to pass pt_regs * 145 * and extract arguments for do_fork() from there. Eventually we might 146 * go for calling do_fork() directly from the wrapper, but only after we 147 * are finished with do_fork() prototype conversion. 148 */ 149 asmlinkage int m68k_clone(struct pt_regs *regs) 150 { 151 /* regs will be equal to current_pt_regs() */ 152 return do_fork(regs->d1, regs->d2, regs, 0, 153 (int __user *)regs->d3, (int __user *)regs->d4); 154 } 155 156 int copy_thread(unsigned long clone_flags, unsigned long usp, 157 unsigned long arg, 158 struct task_struct * p, struct pt_regs * unused) 159 { 160 struct fork_frame { 161 struct switch_stack sw; 162 struct pt_regs regs; 163 } *frame; 164 165 frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1; 166 167 p->thread.ksp = (unsigned long)frame; 168 p->thread.esp0 = (unsigned long)&frame->regs; 169 170 /* 171 * Must save the current SFC/DFC value, NOT the value when 172 * the parent was last descheduled - RGH 10-08-96 173 */ 174 p->thread.fs = get_fs().seg; 175 176 if (unlikely(p->flags & PF_KTHREAD)) { 177 /* kernel thread */ 178 memset(frame, 0, sizeof(struct fork_frame)); 179 frame->regs.sr = PS_S; 180 frame->sw.a3 = usp; /* function */ 181 frame->sw.d7 = arg; 182 frame->sw.retpc = (unsigned long)ret_from_kernel_thread; 183 p->thread.usp = 0; 184 return 0; 185 } 186 memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs), 187 sizeof(struct fork_frame)); 188 frame->regs.d0 = 0; 189 frame->sw.retpc = (unsigned long)ret_from_fork; 190 p->thread.usp = usp ?: rdusp(); 191 192 if (clone_flags & CLONE_SETTLS) 193 task_thread_info(p)->tp_value = frame->regs.d5; 194 195 #ifdef CONFIG_FPU 196 if (!FPU_IS_EMU) { 197 /* Copy the current fpu state */ 198 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory"); 199 200 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) { 201 if (CPU_IS_COLDFIRE) { 202 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t" 203 "fmovel %/fpiar,%1\n\t" 204 "fmovel %/fpcr,%2\n\t" 205 "fmovel %/fpsr,%3" 206 : 207 : "m" (p->thread.fp[0]), 208 "m" (p->thread.fpcntl[0]), 209 "m" (p->thread.fpcntl[1]), 210 "m" (p->thread.fpcntl[2]) 211 : "memory"); 212 } else { 213 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t" 214 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1" 215 : 216 : "m" (p->thread.fp[0]), 217 "m" (p->thread.fpcntl[0]) 218 : "memory"); 219 } 220 } 221 222 /* Restore the state in case the fpu was busy */ 223 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0])); 224 } 225 #endif /* CONFIG_FPU */ 226 227 return 0; 228 } 229 230 /* Fill in the fpu structure for a core dump. */ 231 #ifdef CONFIG_FPU 232 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu) 233 { 234 char fpustate[216]; 235 236 if (FPU_IS_EMU) { 237 int i; 238 239 memcpy(fpu->fpcntl, current->thread.fpcntl, 12); 240 memcpy(fpu->fpregs, current->thread.fp, 96); 241 /* Convert internal fpu reg representation 242 * into long double format 243 */ 244 for (i = 0; i < 24; i += 3) 245 fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) | 246 ((fpu->fpregs[i] & 0x0000ffff) << 16); 247 return 1; 248 } 249 250 /* First dump the fpu context to avoid protocol violation. */ 251 asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory"); 252 if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2]) 253 return 0; 254 255 if (CPU_IS_COLDFIRE) { 256 asm volatile ("fmovel %/fpiar,%0\n\t" 257 "fmovel %/fpcr,%1\n\t" 258 "fmovel %/fpsr,%2\n\t" 259 "fmovemd %/fp0-%/fp7,%3" 260 : 261 : "m" (fpu->fpcntl[0]), 262 "m" (fpu->fpcntl[1]), 263 "m" (fpu->fpcntl[2]), 264 "m" (fpu->fpregs[0]) 265 : "memory"); 266 } else { 267 asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0" 268 : 269 : "m" (fpu->fpcntl[0]) 270 : "memory"); 271 asm volatile ("fmovemx %/fp0-%/fp7,%0" 272 : 273 : "m" (fpu->fpregs[0]) 274 : "memory"); 275 } 276 277 return 1; 278 } 279 EXPORT_SYMBOL(dump_fpu); 280 #endif /* CONFIG_FPU */ 281 282 unsigned long get_wchan(struct task_struct *p) 283 { 284 unsigned long fp, pc; 285 unsigned long stack_page; 286 int count = 0; 287 if (!p || p == current || p->state == TASK_RUNNING) 288 return 0; 289 290 stack_page = (unsigned long)task_stack_page(p); 291 fp = ((struct switch_stack *)p->thread.ksp)->a6; 292 do { 293 if (fp < stack_page+sizeof(struct thread_info) || 294 fp >= 8184+stack_page) 295 return 0; 296 pc = ((unsigned long *)fp)[1]; 297 if (!in_sched_functions(pc)) 298 return pc; 299 fp = *(unsigned long *) fp; 300 } while (count++ < 16); 301 return 0; 302 } 303