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  * "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 }