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/fs.h>
  19 #include <linux/smp.h>
  20 #include <linux/smp_lock.h>
  21 #include <linux/stddef.h>
  22 #include <linux/unistd.h>
  23 #include <linux/ptrace.h>
  24 #include <linux/slab.h>
  25 #include <linux/user.h>
  26 #include <linux/reboot.h>
  27 #include <linux/init_task.h>
  28 #include <linux/mqueue.h>
  29
  30 #include <asm/uaccess.h>
  31 #include <asm/system.h>
  32 #include <asm/traps.h>
  33 #include <asm/machdep.h>
  34 #include <asm/setup.h>
  35 #include <asm/pgtable.h>
  36
  37 /*
  38  * Initial task/thread structure. Make this a per-architecture thing,
  39  * because different architectures tend to have different
  40  * alignment requirements and potentially different initial
  41  * setup.
  42  */
  43 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  44 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  45 union thread_union init_thread_union
  46 __attribute__((section(".data.init_task"), aligned(THREAD_SIZE)))
  47        = { INIT_THREAD_INFO(init_task) };
  48
  49 /* initial task structure */
  50 struct task_struct init_task = INIT_TASK(init_task);
  51
  52 EXPORT_SYMBOL(init_task);
  53
  54 asmlinkage void ret_from_fork(void);
  55
  56
  57 /*
  58  * Return saved PC from a blocked thread
  59  */
  60 unsigned long thread_saved_pc(struct task_struct *tsk)
  61 {
  62         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  63         /* Check whether the thread is blocked in resume() */
  64         if (in_sched_functions(sw->retpc))
  65                 return ((unsigned long *)sw->a6)[1];
  66         else
  67                 return sw->retpc;
  68 }
  69
  70 /*
  71  * The idle loop on an m68k..
  72  */
  73 static void default_idle(void)
  74 {
  75         if (!need_resched())
  76 #if defined(MACH_ATARI_ONLY)
  77                 /* block out HSYNC on the atari (falcon) */
  78                 __asm__("stop #0x2200" : : : "cc");
  79 #else
  80                 __asm__("stop #0x2000" : : : "cc");
  81 #endif
  82 }
  83
  84 void (*idle)(void) = default_idle;
  85
  86 /*
  87  * The idle thread. There's no useful work to be
  88  * done, so just try to conserve power and have a
  89  * low exit latency (ie sit in a loop waiting for
  90  * somebody to say that they'd like to reschedule)
  91  */
  92 void cpu_idle(void)
  93 {
  94         /* endless idle loop with no priority at all */
  95         while (1) {
  96                 while (!need_resched())
  97                         idle();
  98                 preempt_enable_no_resched();
  99                 schedule();
 100                 preempt_disable();
 101         }
 102 }
 103
 104 void machine_restart(char * __unused)
 105 {
 106         if (mach_reset)
 107                 mach_reset();
 108         for (;;);
 109 }
 110
 111 void machine_halt(void)
 112 {
 113         if (mach_halt)
 114                 mach_halt();
 115         for (;;);
 116 }
 117
 118 void machine_power_off(void)
 119 {
 120         if (mach_power_off)
 121                 mach_power_off();
 122         for (;;);
 123 }
 124
 125 void (*pm_power_off)(void) = machine_power_off;
 126 EXPORT_SYMBOL(pm_power_off);
 127
 128 void show_regs(struct pt_regs * regs)
 129 {
 130         printk("\n");
 131         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
 132                regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
 133         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
 134                regs->orig_d0, regs->d0, regs->a2, regs->a1);
 135         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
 136                regs->a0, regs->d5, regs->d4);
 137         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
 138                regs->d3, regs->d2, regs->d1);
 139         if (!(regs->sr & PS_S))
 140                 printk("USP: %08lx\n", rdusp());
 141 }
 142
 143 /*
 144  * Create a kernel thread
 145  */
 146 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 147 {
 148         int pid;
 149         mm_segment_t fs;
 150
 151         fs = get_fs();
 152         set_fs (KERNEL_DS);
 153
 154         {
 155         register long retval __asm__ ("d0");
 156         register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 157
 158         retval = __NR_clone;
 159         __asm__ __volatile__
 160           ("clrl %%d2\n\t"
 161            "trap #0\n\t"                /* Linux/m68k system call */
 162            "tstl %0\n\t"                /* child or parent */
 163            "jne 1f\n\t"                 /* parent - jump */
 164            "lea %%sp@(%c7),%6\n\t"      /* reload current */
 165            "movel %6@,%6\n\t"
 166            "movel %3,%%sp@-\n\t"        /* push argument */
 167            "jsr %4@\n\t"                /* call fn */
 168            "movel %0,%%d1\n\t"          /* pass exit value */
 169            "movel %2,%%d0\n\t"          /* exit */
 170            "trap #0\n"
 171            "1:"
 172            : "+d" (retval)
 173            : "i" (__NR_clone), "i" (__NR_exit),
 174              "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
 175              "i" (-THREAD_SIZE)
 176            : "d2");
 177
 178         pid = retval;
 179         }
 180
 181         set_fs (fs);
 182         return pid;
 183 }
 184 EXPORT_SYMBOL(kernel_thread);
 185
 186 void flush_thread(void)
 187 {
 188         unsigned long zero = 0;
 189         set_fs(USER_DS);
 190         current->thread.fs = __USER_DS;
 191         if (!FPU_IS_EMU)
 192                 asm volatile (".chip 68k/68881\n\t"
 193                               "frestore %0@\n\t"
 194                               ".chip 68k" : : "a" (&zero));
 195 }
 196
 197 /*
 198  * "m68k_fork()".. By the time we get here, the
 199  * non-volatile registers have also been saved on the
 200  * stack. We do some ugly pointer stuff here.. (see
 201  * also copy_thread)
 202  */
 203
 204 asmlinkage int m68k_fork(struct pt_regs *regs)
 205 {
 206         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 207 }
 208
 209 asmlinkage int m68k_vfork(struct pt_regs *regs)
 210 {
 211         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
 212                        NULL, NULL);
 213 }
 214
 215 asmlinkage int m68k_clone(struct pt_regs *regs)
 216 {
 217         unsigned long clone_flags;
 218         unsigned long newsp;
 219         int __user *parent_tidptr, *child_tidptr;
 220
 221         /* syscall2 puts clone_flags in d1 and usp in d2 */
 222         clone_flags = regs->d1;
 223         newsp = regs->d2;
 224         parent_tidptr = (int __user *)regs->d3;
 225         child_tidptr = (int __user *)regs->d4;
 226         if (!newsp)
 227                 newsp = rdusp();
 228         return do_fork(clone_flags, newsp, regs, 0,
 229                        parent_tidptr, child_tidptr);
 230 }
 231
 232 int copy_thread(unsigned long clone_flags, unsigned long usp,
 233                  unsigned long unused,
 234                  struct task_struct * p, struct pt_regs * regs)
 235 {
 236         struct pt_regs * childregs;
 237         struct switch_stack * childstack, *stack;
 238         unsigned long *retp;
 239
 240         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 241
 242         *childregs = *regs;
 243         childregs->d0 = 0;
 244
 245         retp = ((unsigned long *) regs);
 246         stack = ((struct switch_stack *) retp) - 1;
 247
 248         childstack = ((struct switch_stack *) childregs) - 1;
 249         *childstack = *stack;
 250         childstack->retpc = (unsigned long)ret_from_fork;
 251
 252         p->thread.usp = usp;
 253         p->thread.ksp = (unsigned long)childstack;
 254         /*
 255          * Must save the current SFC/DFC value, NOT the value when
 256          * the parent was last descheduled - RGH  10-08-96
 257          */
 258         p->thread.fs = get_fs().seg;
 259
 260         if (!FPU_IS_EMU) {
 261                 /* Copy the current fpu state */
 262                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 263
 264                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
 265                   asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 266                                 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 267                                 : : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
 268                                 : "memory");
 269                 /* Restore the state in case the fpu was busy */
 270                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 271         }
 272
 273         return 0;
 274 }
 275
 276 /* Fill in the fpu structure for a core dump.  */
 277
 278 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 279 {
 280         char fpustate[216];
 281
 282         if (FPU_IS_EMU) {
 283                 int i;
 284
 285                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 286                 memcpy(fpu->fpregs, current->thread.fp, 96);
 287                 /* Convert internal fpu reg representation
 288                  * into long double format
 289                  */
 290                 for (i = 0; i < 24; i += 3)
 291                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 292                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 293                 return 1;
 294         }
 295
 296         /* First dump the fpu context to avoid protocol violation.  */
 297         asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 298         if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 299                 return 0;
 300
 301         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 302                 :: "m" (fpu->fpcntl[0])
 303                 : "memory");
 304         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 305                 :: "m" (fpu->fpregs[0])
 306                 : "memory");
 307         return 1;
 308 }
 309 EXPORT_SYMBOL(dump_fpu);
 310
 311 /*
 312  * sys_execve() executes a new program.
 313  */
 314 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 315 {
 316         int error;
 317         char * filename;
 318         struct pt_regs *regs = (struct pt_regs *) &name;
 319
 320         lock_kernel();
 321         filename = getname(name);
 322         error = PTR_ERR(filename);
 323         if (IS_ERR(filename))
 324                 goto out;
 325         error = do_execve(filename, argv, envp, regs);
 326         putname(filename);
 327 out:
 328         unlock_kernel();
 329         return error;
 330 }
 331
 332 unsigned long get_wchan(struct task_struct *p)
 333 {
 334         unsigned long fp, pc;
 335         unsigned long stack_page;
 336         int count = 0;
 337         if (!p || p == current || p->state == TASK_RUNNING)
 338                 return 0;
 339
 340         stack_page = (unsigned long)task_stack_page(p);
 341         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 342         do {
 343                 if (fp < stack_page+sizeof(struct thread_info) ||
 344                     fp >= 8184+stack_page)
 345                         return 0;
 346                 pc = ((unsigned long *)fp)[1];
 347                 if (!in_sched_functions(pc))
 348                         return pc;
 349                 fp = *(unsigned long *) fp;
 350         } while (count++ < 16);
 351         return 0;
 352 }