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 fs_struct init_fs = INIT_FS;
  44 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  45 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  46 struct mm_struct init_mm = INIT_MM(init_mm);
  47
  48 EXPORT_SYMBOL(init_mm);
  49
  50 union thread_union init_thread_union
  51 __attribute__((section(".data.init_task"), aligned(THREAD_SIZE)))
  52        = { INIT_THREAD_INFO(init_task) };
  53
  54 /* initial task structure */
  55 struct task_struct init_task = INIT_TASK(init_task);
  56
  57 EXPORT_SYMBOL(init_task);
  58
  59 asmlinkage void ret_from_fork(void);
  60
  61
  62 /*
  63  * Return saved PC from a blocked thread
  64  */
  65 unsigned long thread_saved_pc(struct task_struct *tsk)
  66 {
  67         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  68         /* Check whether the thread is blocked in resume() */
  69         if (in_sched_functions(sw->retpc))
  70                 return ((unsigned long *)sw->a6)[1];
  71         else
  72                 return sw->retpc;
  73 }
  74
  75 /*
  76  * The idle loop on an m68k..
  77  */
  78 static void default_idle(void)
  79 {
  80         if (!need_resched())
  81 #if defined(MACH_ATARI_ONLY) && !defined(CONFIG_HADES)
  82                 /* block out HSYNC on the atari (falcon) */
  83                 __asm__("stop #0x2200" : : : "cc");
  84 #else
  85                 __asm__("stop #0x2000" : : : "cc");
  86 #endif
  87 }
  88
  89 void (*idle)(void) = default_idle;
  90
  91 /*
  92  * The idle thread. There's no useful work to be
  93  * done, so just try to conserve power and have a
  94  * low exit latency (ie sit in a loop waiting for
  95  * somebody to say that they'd like to reschedule)
  96  */
  97 void cpu_idle(void)
  98 {
  99         /* endless idle loop with no priority at all */
 100         while (1) {
 101                 while (!need_resched())
 102                         idle();
 103                 preempt_enable_no_resched();
 104                 schedule();
 105                 preempt_disable();
 106         }
 107 }
 108
 109 void machine_restart(char * __unused)
 110 {
 111         if (mach_reset)
 112                 mach_reset();
 113         for (;;);
 114 }
 115
 116 void machine_halt(void)
 117 {
 118         if (mach_halt)
 119                 mach_halt();
 120         for (;;);
 121 }
 122
 123 void machine_power_off(void)
 124 {
 125         if (mach_power_off)
 126                 mach_power_off();
 127         for (;;);
 128 }
 129
 130 void (*pm_power_off)(void) = machine_power_off;
 131 EXPORT_SYMBOL(pm_power_off);
 132
 133 void show_regs(struct pt_regs * regs)
 134 {
 135         printk("\n");
 136         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
 137                regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
 138         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
 139                regs->orig_d0, regs->d0, regs->a2, regs->a1);
 140         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
 141                regs->a0, regs->d5, regs->d4);
 142         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
 143                regs->d3, regs->d2, regs->d1);
 144         if (!(regs->sr & PS_S))
 145                 printk("USP: %08lx\n", rdusp());
 146 }
 147
 148 /*
 149  * Create a kernel thread
 150  */
 151 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 152 {
 153         int pid;
 154         mm_segment_t fs;
 155
 156         fs = get_fs();
 157         set_fs (KERNEL_DS);
 158
 159         {
 160         register long retval __asm__ ("d0");
 161         register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 162
 163         retval = __NR_clone;
 164         __asm__ __volatile__
 165           ("clrl %%d2\n\t"
 166            "trap #0\n\t"                /* Linux/m68k system call */
 167            "tstl %0\n\t"                /* child or parent */
 168            "jne 1f\n\t"                 /* parent - jump */
 169            "lea %%sp@(%c7),%6\n\t"      /* reload current */
 170            "movel %6@,%6\n\t"
 171            "movel %3,%%sp@-\n\t"        /* push argument */
 172            "jsr %4@\n\t"                /* call fn */
 173            "movel %0,%%d1\n\t"          /* pass exit value */
 174            "movel %2,%%d0\n\t"          /* exit */
 175            "trap #0\n"
 176            "1:"
 177            : "+d" (retval)
 178            : "i" (__NR_clone), "i" (__NR_exit),
 179              "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
 180              "i" (-THREAD_SIZE)
 181            : "d2");
 182
 183         pid = retval;
 184         }
 185
 186         set_fs (fs);
 187         return pid;
 188 }
 189 EXPORT_SYMBOL(kernel_thread);
 190
 191 void flush_thread(void)
 192 {
 193         unsigned long zero = 0;
 194         set_fs(USER_DS);
 195         current->thread.fs = __USER_DS;
 196         if (!FPU_IS_EMU)
 197                 asm volatile (".chip 68k/68881\n\t"
 198                               "frestore %0@\n\t"
 199                               ".chip 68k" : : "a" (&zero));
 200 }
 201
 202 /*
 203  * "m68k_fork()".. By the time we get here, the
 204  * non-volatile registers have also been saved on the
 205  * stack. We do some ugly pointer stuff here.. (see
 206  * also copy_thread)
 207  */
 208
 209 asmlinkage int m68k_fork(struct pt_regs *regs)
 210 {
 211         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 212 }
 213
 214 asmlinkage int m68k_vfork(struct pt_regs *regs)
 215 {
 216         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
 217                        NULL, NULL);
 218 }
 219
 220 asmlinkage int m68k_clone(struct pt_regs *regs)
 221 {
 222         unsigned long clone_flags;
 223         unsigned long newsp;
 224         int __user *parent_tidptr, *child_tidptr;
 225
 226         /* syscall2 puts clone_flags in d1 and usp in d2 */
 227         clone_flags = regs->d1;
 228         newsp = regs->d2;
 229         parent_tidptr = (int __user *)regs->d3;
 230         child_tidptr = (int __user *)regs->d4;
 231         if (!newsp)
 232                 newsp = rdusp();
 233         return do_fork(clone_flags, newsp, regs, 0,
 234                        parent_tidptr, child_tidptr);
 235 }
 236
 237 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 238                  unsigned long unused,
 239                  struct task_struct * p, struct pt_regs * regs)
 240 {
 241         struct pt_regs * childregs;
 242         struct switch_stack * childstack, *stack;
 243         unsigned long *retp;
 244
 245         childregs = (struct pt_regs *) (task_stack_page(p) + THREAD_SIZE) - 1;
 246
 247         *childregs = *regs;
 248         childregs->d0 = 0;
 249
 250         retp = ((unsigned long *) regs);
 251         stack = ((struct switch_stack *) retp) - 1;
 252
 253         childstack = ((struct switch_stack *) childregs) - 1;
 254         *childstack = *stack;
 255         childstack->retpc = (unsigned long)ret_from_fork;
 256
 257         p->thread.usp = usp;
 258         p->thread.ksp = (unsigned long)childstack;
 259         /*
 260          * Must save the current SFC/DFC value, NOT the value when
 261          * the parent was last descheduled - RGH  10-08-96
 262          */
 263         p->thread.fs = get_fs().seg;
 264
 265         if (!FPU_IS_EMU) {
 266                 /* Copy the current fpu state */
 267                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 268
 269                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
 270                   asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 271                                 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 272                                 : : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
 273                                 : "memory");
 274                 /* Restore the state in case the fpu was busy */
 275                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 276         }
 277
 278         return 0;
 279 }
 280
 281 /* Fill in the fpu structure for a core dump.  */
 282
 283 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 284 {
 285         char fpustate[216];
 286
 287         if (FPU_IS_EMU) {
 288                 int i;
 289
 290                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 291                 memcpy(fpu->fpregs, current->thread.fp, 96);
 292                 /* Convert internal fpu reg representation
 293                  * into long double format
 294                  */
 295                 for (i = 0; i < 24; i += 3)
 296                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 297                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 298                 return 1;
 299         }
 300
 301         /* First dump the fpu context to avoid protocol violation.  */
 302         asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 303         if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 304                 return 0;
 305
 306         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 307                 :: "m" (fpu->fpcntl[0])
 308                 : "memory");
 309         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 310                 :: "m" (fpu->fpregs[0])
 311                 : "memory");
 312         return 1;
 313 }
 314 EXPORT_SYMBOL(dump_fpu);
 315
 316 /*
 317  * sys_execve() executes a new program.
 318  */
 319 asmlinkage int sys_execve(char __user *name, char __user * __user *argv, char __user * __user *envp)
 320 {
 321         int error;
 322         char * filename;
 323         struct pt_regs *regs = (struct pt_regs *) &name;
 324
 325         lock_kernel();
 326         filename = getname(name);
 327         error = PTR_ERR(filename);
 328         if (IS_ERR(filename))
 329                 goto out;
 330         error = do_execve(filename, argv, envp, regs);
 331         putname(filename);
 332 out:
 333         unlock_kernel();
 334         return error;
 335 }
 336
 337 unsigned long get_wchan(struct task_struct *p)
 338 {
 339         unsigned long fp, pc;
 340         unsigned long stack_page;
 341         int count = 0;
 342         if (!p || p == current || p->state == TASK_RUNNING)
 343                 return 0;
 344
 345         stack_page = (unsigned long)task_stack_page(p);
 346         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 347         do {
 348                 if (fp < stack_page+sizeof(struct thread_info) ||
 349                     fp >= 8184+stack_page)
 350                         return 0;
 351                 pc = ((unsigned long *)fp)[1];
 352                 if (!in_sched_functions(pc))
 353                         return pc;
 354                 fp = *(unsigned long *) fp;
 355         } while (count++ < 16);
 356         return 0;
 357 }