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/config.h>
  14 #include <linux/errno.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.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/a.out.h>
  27 #include <linux/reboot.h>
  28 #include <linux/init_task.h>
  29 #include <linux/mqueue.h>
  30
  31 #include <asm/uaccess.h>
  32 #include <asm/system.h>
  33 #include <asm/traps.h>
  34 #include <asm/machdep.h>
  35 #include <asm/setup.h>
  36 #include <asm/pgtable.h>
  37
  38 /*
  39  * Initial task/thread structure. Make this a per-architecture thing,
  40  * because different architectures tend to have different
  41  * alignment requirements and potentially different initial
  42  * setup.
  43  */
  44 static struct fs_struct init_fs = INIT_FS;
  45 static struct files_struct init_files = INIT_FILES;
  46 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  47 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  48 struct mm_struct init_mm = INIT_MM(init_mm);
  49
  50 EXPORT_SYMBOL(init_mm);
  51
  52 union thread_union init_thread_union
  53 __attribute__((section(".data.init_task"), aligned(THREAD_SIZE)))
  54        = { INIT_THREAD_INFO(init_task) };
  55
  56 /* initial task structure */
  57 struct task_struct init_task = INIT_TASK(init_task);
  58
  59 EXPORT_SYMBOL(init_task);
  60
  61 asmlinkage void ret_from_fork(void);
  62
  63
  64 /*
  65  * Return saved PC from a blocked thread
  66  */
  67 unsigned long thread_saved_pc(struct task_struct *tsk)
  68 {
  69         struct switch_stack *sw = (struct switch_stack *)tsk->thread.ksp;
  70         /* Check whether the thread is blocked in resume() */
  71         if (in_sched_functions(sw->retpc))
  72                 return ((unsigned long *)sw->a6)[1];
  73         else
  74                 return sw->retpc;
  75 }
  76
  77 /*
  78  * The idle loop on an m68k..
  79  */
  80 void default_idle(void)
  81 {
  82         if (!need_resched())
  83 #if defined(MACH_ATARI_ONLY) && !defined(CONFIG_HADES)
  84                 /* block out HSYNC on the atari (falcon) */
  85                 __asm__("stop #0x2200" : : : "cc");
  86 #else
  87                 __asm__("stop #0x2000" : : : "cc");
  88 #endif
  89 }
  90
  91 void (*idle)(void) = default_idle;
  92
  93 /*
  94  * The idle thread. There's no useful work to be
  95  * done, so just try to conserve power and have a
  96  * low exit latency (ie sit in a loop waiting for
  97  * somebody to say that they'd like to reschedule)
  98  */
  99 void cpu_idle(void)
 100 {
 101         /* endless idle loop with no priority at all */
 102         while (1) {
 103                 while (!need_resched())
 104                         idle();
 105                 schedule();
 106         }
 107 }
 108
 109 void machine_restart(char * __unused)
 110 {
 111         if (mach_reset)
 112                 mach_reset();
 113         for (;;);
 114 }
 115
 116 EXPORT_SYMBOL(machine_restart);
 117
 118 void machine_halt(void)
 119 {
 120         if (mach_halt)
 121                 mach_halt();
 122         for (;;);
 123 }
 124
 125 EXPORT_SYMBOL(machine_halt);
 126
 127 void machine_power_off(void)
 128 {
 129         if (mach_power_off)
 130                 mach_power_off();
 131         for (;;);
 132 }
 133
 134 EXPORT_SYMBOL(machine_power_off);
 135
 136 void show_regs(struct pt_regs * regs)
 137 {
 138         printk("\n");
 139         printk("Format %02x  Vector: %04x  PC: %08lx  Status: %04x    %s\n",
 140                regs->format, regs->vector, regs->pc, regs->sr, print_tainted());
 141         printk("ORIG_D0: %08lx  D0: %08lx  A2: %08lx  A1: %08lx\n",
 142                regs->orig_d0, regs->d0, regs->a2, regs->a1);
 143         printk("A0: %08lx  D5: %08lx  D4: %08lx\n",
 144                regs->a0, regs->d5, regs->d4);
 145         printk("D3: %08lx  D2: %08lx  D1: %08lx\n",
 146                regs->d3, regs->d2, regs->d1);
 147         if (!(regs->sr & PS_S))
 148                 printk("USP: %08lx\n", rdusp());
 149 }
 150
 151 /*
 152  * Create a kernel thread
 153  */
 154 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
 155 {
 156         int pid;
 157         mm_segment_t fs;
 158
 159         fs = get_fs();
 160         set_fs (KERNEL_DS);
 161
 162         {
 163         register long retval __asm__ ("d0");
 164         register long clone_arg __asm__ ("d1") = flags | CLONE_VM | CLONE_UNTRACED;
 165
 166         retval = __NR_clone;
 167         __asm__ __volatile__
 168           ("clrl %%d2\n\t"
 169            "trap #0\n\t"                /* Linux/m68k system call */
 170            "tstl %0\n\t"                /* child or parent */
 171            "jne 1f\n\t"                 /* parent - jump */
 172            "lea %%sp@(%c7),%6\n\t"      /* reload current */
 173            "movel %6@,%6\n\t"
 174            "movel %3,%%sp@-\n\t"        /* push argument */
 175            "jsr %4@\n\t"                /* call fn */
 176            "movel %0,%%d1\n\t"          /* pass exit value */
 177            "movel %2,%%d0\n\t"          /* exit */
 178            "trap #0\n"
 179            "1:"
 180            : "+d" (retval)
 181            : "i" (__NR_clone), "i" (__NR_exit),
 182              "r" (arg), "a" (fn), "d" (clone_arg), "r" (current),
 183              "i" (-THREAD_SIZE)
 184            : "d2");
 185
 186         pid = retval;
 187         }
 188
 189         set_fs (fs);
 190         return pid;
 191 }
 192
 193 void flush_thread(void)
 194 {
 195         unsigned long zero = 0;
 196         set_fs(USER_DS);
 197         current->thread.fs = __USER_DS;
 198         if (!FPU_IS_EMU)
 199                 asm volatile (".chip 68k/68881\n\t"
 200                               "frestore %0@\n\t"
 201                               ".chip 68k" : : "a" (&zero));
 202 }
 203
 204 /*
 205  * "m68k_fork()".. By the time we get here, the
 206  * non-volatile registers have also been saved on the
 207  * stack. We do some ugly pointer stuff here.. (see
 208  * also copy_thread)
 209  */
 210
 211 asmlinkage int m68k_fork(struct pt_regs *regs)
 212 {
 213         return do_fork(SIGCHLD, rdusp(), regs, 0, NULL, NULL);
 214 }
 215
 216 asmlinkage int m68k_vfork(struct pt_regs *regs)
 217 {
 218         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, rdusp(), regs, 0,
 219                        NULL, NULL);
 220 }
 221
 222 asmlinkage int m68k_clone(struct pt_regs *regs)
 223 {
 224         unsigned long clone_flags;
 225         unsigned long newsp;
 226         int *parent_tidptr, *child_tidptr;
 227
 228         /* syscall2 puts clone_flags in d1 and usp in d2 */
 229         clone_flags = regs->d1;
 230         newsp = regs->d2;
 231         parent_tidptr = (int *)regs->d3;
 232         child_tidptr = (int *)regs->d4;
 233         if (!newsp)
 234                 newsp = rdusp();
 235         return do_fork(clone_flags, newsp, regs, 0,
 236                        parent_tidptr, child_tidptr);
 237 }
 238
 239 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 240                  unsigned long unused,
 241                  struct task_struct * p, struct pt_regs * regs)
 242 {
 243         struct pt_regs * childregs;
 244         struct switch_stack * childstack, *stack;
 245         unsigned long stack_offset, *retp;
 246
 247         stack_offset = THREAD_SIZE - sizeof(struct pt_regs);
 248         childregs = (struct pt_regs *) ((unsigned long) (p->thread_info) + stack_offset);
 249
 250         *childregs = *regs;
 251         childregs->d0 = 0;
 252
 253         retp = ((unsigned long *) regs);
 254         stack = ((struct switch_stack *) retp) - 1;
 255
 256         childstack = ((struct switch_stack *) childregs) - 1;
 257         *childstack = *stack;
 258         childstack->retpc = (unsigned long)ret_from_fork;
 259
 260         p->thread.usp = usp;
 261         p->thread.ksp = (unsigned long)childstack;
 262         /*
 263          * Must save the current SFC/DFC value, NOT the value when
 264          * the parent was last descheduled - RGH  10-08-96
 265          */
 266         p->thread.fs = get_fs().seg;
 267
 268         if (!FPU_IS_EMU) {
 269                 /* Copy the current fpu state */
 270                 asm volatile ("fsave %0" : : "m" (p->thread.fpstate[0]) : "memory");
 271
 272                 if (!CPU_IS_060 ? p->thread.fpstate[0] : p->thread.fpstate[2])
 273                   asm volatile ("fmovemx %/fp0-%/fp7,%0\n\t"
 274                                 "fmoveml %/fpiar/%/fpcr/%/fpsr,%1"
 275                                 : : "m" (p->thread.fp[0]), "m" (p->thread.fpcntl[0])
 276                                 : "memory");
 277                 /* Restore the state in case the fpu was busy */
 278                 asm volatile ("frestore %0" : : "m" (p->thread.fpstate[0]));
 279         }
 280
 281         return 0;
 282 }
 283
 284 /* Fill in the fpu structure for a core dump.  */
 285
 286 int dump_fpu (struct pt_regs *regs, struct user_m68kfp_struct *fpu)
 287 {
 288         char fpustate[216];
 289
 290         if (FPU_IS_EMU) {
 291                 int i;
 292
 293                 memcpy(fpu->fpcntl, current->thread.fpcntl, 12);
 294                 memcpy(fpu->fpregs, current->thread.fp, 96);
 295                 /* Convert internal fpu reg representation
 296                  * into long double format
 297                  */
 298                 for (i = 0; i < 24; i += 3)
 299                         fpu->fpregs[i] = ((fpu->fpregs[i] & 0xffff0000) << 15) |
 300                                          ((fpu->fpregs[i] & 0x0000ffff) << 16);
 301                 return 1;
 302         }
 303
 304         /* First dump the fpu context to avoid protocol violation.  */
 305         asm volatile ("fsave %0" :: "m" (fpustate[0]) : "memory");
 306         if (!CPU_IS_060 ? !fpustate[0] : !fpustate[2])
 307                 return 0;
 308
 309         asm volatile ("fmovem %/fpiar/%/fpcr/%/fpsr,%0"
 310                 :: "m" (fpu->fpcntl[0])
 311                 : "memory");
 312         asm volatile ("fmovemx %/fp0-%/fp7,%0"
 313                 :: "m" (fpu->fpregs[0])
 314                 : "memory");
 315         return 1;
 316 }
 317
 318 /*
 319  * fill in the user structure for a core dump..
 320  */
 321 void dump_thread(struct pt_regs * regs, struct user * dump)
 322 {
 323         struct switch_stack *sw;
 324
 325 /* changed the size calculations - should hopefully work better. lbt */
 326         dump->magic = CMAGIC;
 327         dump->start_code = 0;
 328         dump->start_stack = rdusp() & ~(PAGE_SIZE - 1);
 329         dump->u_tsize = ((unsigned long) current->mm->end_code) >> PAGE_SHIFT;
 330         dump->u_dsize = ((unsigned long) (current->mm->brk +
 331                                           (PAGE_SIZE-1))) >> PAGE_SHIFT;
 332         dump->u_dsize -= dump->u_tsize;
 333         dump->u_ssize = 0;
 334
 335         if (dump->start_stack < TASK_SIZE)
 336                 dump->u_ssize = ((unsigned long) (TASK_SIZE - dump->start_stack)) >> PAGE_SHIFT;
 337
 338         dump->u_ar0 = (struct user_regs_struct *)((int)&dump->regs - (int)dump);
 339         sw = ((struct switch_stack *)regs) - 1;
 340         dump->regs.d1 = regs->d1;
 341         dump->regs.d2 = regs->d2;
 342         dump->regs.d3 = regs->d3;
 343         dump->regs.d4 = regs->d4;
 344         dump->regs.d5 = regs->d5;
 345         dump->regs.d6 = sw->d6;
 346         dump->regs.d7 = sw->d7;
 347         dump->regs.a0 = regs->a0;
 348         dump->regs.a1 = regs->a1;
 349         dump->regs.a2 = regs->a2;
 350         dump->regs.a3 = sw->a3;
 351         dump->regs.a4 = sw->a4;
 352         dump->regs.a5 = sw->a5;
 353         dump->regs.a6 = sw->a6;
 354         dump->regs.d0 = regs->d0;
 355         dump->regs.orig_d0 = regs->orig_d0;
 356         dump->regs.stkadj = regs->stkadj;
 357         dump->regs.sr = regs->sr;
 358         dump->regs.pc = regs->pc;
 359         dump->regs.fmtvec = (regs->format << 12) | regs->vector;
 360         /* dump floating point stuff */
 361         dump->u_fpvalid = dump_fpu (regs, &dump->m68kfp);
 362 }
 363
 364 /*
 365  * sys_execve() executes a new program.
 366  */
 367 asmlinkage int sys_execve(char *name, char **argv, char **envp)
 368 {
 369         int error;
 370         char * filename;
 371         struct pt_regs *regs = (struct pt_regs *) &name;
 372
 373         lock_kernel();
 374         filename = getname(name);
 375         error = PTR_ERR(filename);
 376         if (IS_ERR(filename))
 377                 goto out;
 378         error = do_execve(filename, argv, envp, regs);
 379         putname(filename);
 380 out:
 381         unlock_kernel();
 382         return error;
 383 }
 384
 385 unsigned long get_wchan(struct task_struct *p)
 386 {
 387         unsigned long fp, pc;
 388         unsigned long stack_page;
 389         int count = 0;
 390         if (!p || p == current || p->state == TASK_RUNNING)
 391                 return 0;
 392
 393         stack_page = (unsigned long)(p->thread_info);
 394         fp = ((struct switch_stack *)p->thread.ksp)->a6;
 395         do {
 396                 if (fp < stack_page+sizeof(struct thread_info) ||
 397                     fp >= 8184+stack_page)
 398                         return 0;
 399                 pc = ((unsigned long *)fp)[1];
 400                 if (!in_sched_functions(pc))
 401                         return pc;
 402                 fp = *(unsigned long *) fp;
 403         } while (count++ < 16);
 404         return 0;
 405 }