arch/m68k/kernel/process.c

   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, struct task_struct *p)
 158 {
 159         struct fork_frame {
 160                 struct switch_stack sw;
 161                 struct pt_regs regs;
 162         } *frame;
 163
 164         frame = (struct fork_frame *) (task_stack_page(p) + THREAD_SIZE) - 1;
 165
 166         p->thread.ksp = (unsigned long)frame;
 167         p->thread.esp0 = (unsigned long)&frame->regs;
 168
 169         /*
 170          * Must save the current SFC/DFC value, NOT the value when
 171          * the parent was last descheduled - RGH  10-08-96
 172          */
 173         p->thread.fs = get_fs().seg;
 174
 175         if (unlikely(p->flags & PF_KTHREAD)) {
 176                 /* kernel thread */
 177                 memset(frame, 0, sizeof(struct fork_frame));
 178                 frame->regs.sr = PS_S;
 179                 frame->sw.a3 = usp; /* function */
 180                 frame->sw.d7 = arg;
 181                 frame->sw.retpc = (unsigned long)ret_from_kernel_thread;
 182                 p->thread.usp = 0;
 183                 return 0;
 184         }
 185         memcpy(frame, container_of(current_pt_regs(), struct fork_frame, regs),
 186                 sizeof(struct fork_frame));
 187         frame->regs.d0 = 0;
 188         frame->sw.retpc = (unsigned long)ret_from_fork;
 189         p->thread.usp = usp ?: rdusp();
 190
 191         if (clone_flags & CLONE_SETTLS)
 192                 task_thread_info(p)->tp_value = frame->regs.d5;
 193
 194 #ifdef CONFIG_FPU
 195         if (!FPU_IS_EMU) {
 196                 /* Copy the current fpu state */
 197                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 198
 199                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2]) {
 200                         if (CPU_IS_COLDFIRE) {
 201                                 asm volatile ("fmovemd %/fp0-%/fp7,%0\n\t"
 202                                               "fmovel %/fpiar,%1\n\t"
 203                                               "fmovel %/fpcr,%2\n\t"
 204                                               "fmovel %/fpsr,%3"
 205                                               :
 206                                               : "m" (p->thread.fp[0]),
 207                                                 "m" (p->thread.fpcntl[0]),
 208                                                 "m" (p->thread.fpcntl[1]),
 209                                                 "m" (p->thread.fpcntl[2])
 210                                               : "memory");
 211                         } else {
 212                                 asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 213                                               "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 214                                               :
 215                                               : "m" (p->thread.fp[0]),
 216                                                 "m" (p->thread.fpcntl[0])
 217                                               : "memory");
 218                         }
 219                 }
 220
 221                 /* Restore the state in case the fpu was busy */
 222                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 223         }
 224 #endif /* CONFIG_FPU */
 225
 226         return 0;
 227 }
 228
 229 /* Fill in the fpu structure for a core dump.  */
 230 #ifdef CONFIG_FPU
 231 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 232 {
 233         char fpustate[216];
 234
 235         if (FPU_IS_EMU) {
 236                 int i;
 237
 238                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 239                 memcpy(fpu->fpregs, current->thread.fp, 96);
 240                 /* Convert internal fpu reg representation
 241                  * into long double format
 242                  */
 243                 for (i = 0; i < 24; i += 3)
 244                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 245                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 246                 return 1;
 247         }
 248
 249         /* First dump the fpu context to avoid protocol violation.  */
 250         asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 251         if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 252                 return 0;
 253
 254         if (CPU_IS_COLDFIRE) {
 255                 asm volatile ("fmovel %/fpiar,%0\n\t"
 256                               "fmovel %/fpcr,%1\n\t"
 257                               "fmovel %/fpsr,%2\n\t"
 258                               "fmovemd %/fp0-%/fp7,%3"
 259                               :
 260                               : "m" (fpu->fpcntl[0]),
 261                                 "m" (fpu->fpcntl[1]),
 262                                 "m" (fpu->fpcntl[2]),
 263                                 "m" (fpu->fpregs[0])
 264                               : "memory");
 265         } else {
 266                 asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 267                               :
 268                               : "m" (fpu->fpcntl[0])
 269                               : "memory");
 270                 asm volatile ("fmovemx %/fp0-%/fp7,%0"
 271                               :
 272                               : "m" (fpu->fpregs[0])
 273                               : "memory");
 274         }
 275
 276         return 1;
 277 }
 278 EXPORT_SYMBOL(dump_fpu);
 279 #endif /* CONFIG_FPU */
 280
 281 unsigned long get_wchan(struct task_struct *p)
 282 {
 283         unsigned long fp, pc;
 284         unsigned long stack_page;
 285         int count = 0;
 286         if (!p || p == current || p->state == TASK_RUNNING)
 287                 return 0;
 288
 289         stack_page = (unsigned long)task_stack_page(p);
 290         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 291         do {
 292                 if (fp < stack_page+sizeof(struct thread_info) ||
 293                     fp >= 8184+stack_page)
 294                         return 0;
 295                 pc = ((unsigned long *)fp)[1];
 296                 if (!in_sched_functions(pc))
 297                         return pc;
 298                 fp = *(unsigned long *) fp;
 299         } while (count++ < 16);
 300         return 0;
 301 }