arch/ppc/kernel/process.c

   1 /*
   2  *  arch/ppc/kernel/process.c
   3  *
   4  *  Derived from "arch/i386/kernel/process.c"
   5  *    Copyright (C) 1995  Linus Torvalds
   6  *
   7  *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
   8  *  Paul Mackerras (paulus@cs.anu.edu.au)
   9  *
  10  *  PowerPC version
  11  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  12  *
  13  *  This program is free software; you can redistribute it and/or
  14  *  modify it under the terms of the GNU General Public License
  15  *  as published by the Free Software Foundation; either version
  16  *  2 of the License, or (at your option) any later version.
  17  *
  18  */
  19
  20 #include <linux/config.h>
  21 #include <linux/errno.h>
  22 #include <linux/sched.h>
  23 #include <linux/kernel.h>
  24 #include <linux/mm.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/stddef.h>
  28 #include <linux/unistd.h>
  29 #include <linux/ptrace.h>
  30 #include <linux/slab.h>
  31 #include <linux/user.h>
  32 #include <linux/elf.h>
  33 #include <linux/init.h>
  34 #include <linux/prctl.h>
  35 #include <linux/init_task.h>
  36 #include <linux/module.h>
  37 #include <linux/kallsyms.h>
  38 #include <linux/mqueue.h>
  39 #include <linux/hardirq.h>
  40
  41 #include <asm/pgtable.h>
  42 #include <asm/uaccess.h>
  43 #include <asm/system.h>
  44 #include <asm/io.h>
  45 #include <asm/processor.h>
  46 #include <asm/mmu.h>
  47 #include <asm/prom.h>
  48
  49 extern unsigned long _get_SP(void);
  50
  51 struct task_struct *last_task_used_math = NULL;
  52 struct task_struct *last_task_used_altivec = NULL;
  53 struct task_struct *last_task_used_spe = NULL;
  54
  55 static struct fs_struct init_fs = INIT_FS;
  56 static struct files_struct init_files = INIT_FILES;
  57 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  58 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  59 struct mm_struct init_mm = INIT_MM(init_mm);
  60 EXPORT_SYMBOL(init_mm);
  61
  62 /* this is 8kB-aligned so we can get to the thread_info struct
  63    at the base of it from the stack pointer with 1 integer instruction. */
  64 union thread_union init_thread_union
  65         __attribute__((__section__(".data.init_task"))) =
  66 { INIT_THREAD_INFO(init_task) };
  67
  68 /* initial task structure */
  69 struct task_struct init_task = INIT_TASK(init_task);
  70 EXPORT_SYMBOL(init_task);
  71
  72 /* only used to get secondary processor up */
  73 struct task_struct *current_set[NR_CPUS] = {&init_task, };
  74
  75 #undef SHOW_TASK_SWITCHES
  76 #undef CHECK_STACK
  77
  78 #if defined(CHECK_STACK)
  79 unsigned long
  80 kernel_stack_top(struct task_struct *tsk)
  81 {
  82         return ((unsigned long)tsk) + sizeof(union task_union);
  83 }
  84
  85 unsigned long
  86 task_top(struct task_struct *tsk)
  87 {
  88         return ((unsigned long)tsk) + sizeof(struct thread_info);
  89 }
  90
  91 /* check to make sure the kernel stack is healthy */
  92 int check_stack(struct task_struct *tsk)
  93 {
  94         unsigned long stack_top = kernel_stack_top(tsk);
  95         unsigned long tsk_top = task_top(tsk);
  96         int ret = 0;
  97
  98 #if 0
  99         /* check thread magic */
 100         if ( tsk->thread.magic != THREAD_MAGIC )
 101         {
 102                 ret |= 1;
 103                 printk("thread.magic bad: %08x\n", tsk->thread.magic);
 104         }
 105 #endif
 106
 107         if ( !tsk )
 108                 printk("check_stack(): tsk bad tsk %p\n",tsk);
 109
 110         /* check if stored ksp is bad */
 111         if ( (tsk->thread.ksp > stack_top) || (tsk->thread.ksp < tsk_top) )
 112         {
 113                 printk("stack out of bounds: %s/%d\n"
 114                        " tsk_top %08lx ksp %08lx stack_top %08lx\n",
 115                        tsk->comm,tsk->pid,
 116                        tsk_top, tsk->thread.ksp, stack_top);
 117                 ret |= 2;
 118         }
 119
 120         /* check if stack ptr RIGHT NOW is bad */
 121         if ( (tsk == current) && ((_get_SP() > stack_top ) || (_get_SP() < tsk_top)) )
 122         {
 123                 printk("current stack ptr out of bounds: %s/%d\n"
 124                        " tsk_top %08lx sp %08lx stack_top %08lx\n",
 125                        current->comm,current->pid,
 126                        tsk_top, _get_SP(), stack_top);
 127                 ret |= 4;
 128         }
 129
 130 #if 0
 131         /* check amount of free stack */
 132         for ( i = (unsigned long *)task_top(tsk) ; i < kernel_stack_top(tsk) ; i++ )
 133         {
 134                 if ( !i )
 135                         printk("check_stack(): i = %p\n", i);
 136                 if ( *i != 0 )
 137                 {
 138                         /* only notify if it's less than 900 bytes */
 139                         if ( (i - (unsigned long *)task_top(tsk))  < 900 )
 140                                 printk("%d bytes free on stack\n",
 141                                        i - task_top(tsk));
 142                         break;
 143                 }
 144         }
 145 #endif
 146
 147         if (ret)
 148         {
 149                 panic("bad kernel stack");
 150         }
 151         return(ret);
 152 }
 153 #endif /* defined(CHECK_STACK) */
 154
 155 #ifdef CONFIG_ALTIVEC
 156 int
 157 dump_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
 158 {
 159         if (regs->msr & MSR_VEC)
 160                 giveup_altivec(current);
 161         memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
 162         return 1;
 163 }
 164
 165 void
 166 enable_kernel_altivec(void)
 167 {
 168         WARN_ON(preemptible());
 169
 170 #ifdef CONFIG_SMP
 171         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 172                 giveup_altivec(current);
 173         else
 174                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 175 #else
 176         giveup_altivec(last_task_used_altivec);
 177 #endif /* __SMP __ */
 178 }
 179 EXPORT_SYMBOL(enable_kernel_altivec);
 180 #endif /* CONFIG_ALTIVEC */
 181
 182 #ifdef CONFIG_SPE
 183 int
 184 dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 185 {
 186         if (regs->msr & MSR_SPE)
 187                 giveup_spe(current);
 188         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
 189         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
 190         return 1;
 191 }
 192
 193 void
 194 enable_kernel_spe(void)
 195 {
 196         WARN_ON(preemptible());
 197
 198 #ifdef CONFIG_SMP
 199         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 200                 giveup_spe(current);
 201         else
 202                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 203 #else
 204         giveup_spe(last_task_used_spe);
 205 #endif /* __SMP __ */
 206 }
 207 EXPORT_SYMBOL(enable_kernel_spe);
 208 #endif /* CONFIG_SPE */
 209
 210 void
 211 enable_kernel_fp(void)
 212 {
 213         WARN_ON(preemptible());
 214
 215 #ifdef CONFIG_SMP
 216         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 217                 giveup_fpu(current);
 218         else
 219                 giveup_fpu(NULL);       /* just enables FP for kernel */
 220 #else
 221         giveup_fpu(last_task_used_math);
 222 #endif /* CONFIG_SMP */
 223 }
 224 EXPORT_SYMBOL(enable_kernel_fp);
 225
 226 int
 227 dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
 228 {
 229         preempt_disable();
 230         if (tsk->thread.regs && (tsk->thread.regs->msr & MSR_FP))
 231                 giveup_fpu(tsk);
 232         preempt_enable();
 233         memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
 234         return 1;
 235 }
 236
 237 struct task_struct *__switch_to(struct task_struct *prev,
 238         struct task_struct *new)
 239 {
 240         struct thread_struct *new_thread, *old_thread;
 241         unsigned long s;
 242         struct task_struct *last;
 243
 244         local_irq_save(s);
 245 #ifdef CHECK_STACK
 246         check_stack(prev);
 247         check_stack(new);
 248 #endif
 249
 250 #ifdef CONFIG_SMP
 251         /* avoid complexity of lazy save/restore of fpu
 252          * by just saving it every time we switch out if
 253          * this task used the fpu during the last quantum.
 254          *
 255          * If it tries to use the fpu again, it'll trap and
 256          * reload its fp regs.  So we don't have to do a restore
 257          * every switch, just a save.
 258          *  -- Cort
 259          */
 260         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 261                 giveup_fpu(prev);
 262 #ifdef CONFIG_ALTIVEC
 263         /*
 264          * If the previous thread used altivec in the last quantum
 265          * (thus changing altivec regs) then save them.
 266          * We used to check the VRSAVE register but not all apps
 267          * set it, so we don't rely on it now (and in fact we need
 268          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 269          *
 270          * On SMP we always save/restore altivec regs just to avoid the
 271          * complexity of changing processors.
 272          *  -- Cort
 273          */
 274         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_VEC)))
 275                 giveup_altivec(prev);
 276 #endif /* CONFIG_ALTIVEC */
 277 #ifdef CONFIG_SPE
 278         /*
 279          * If the previous thread used spe in the last quantum
 280          * (thus changing spe regs) then save them.
 281          *
 282          * On SMP we always save/restore spe regs just to avoid the
 283          * complexity of changing processors.
 284          */
 285         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 286                 giveup_spe(prev);
 287 #endif /* CONFIG_SPE */
 288 #endif /* CONFIG_SMP */
 289
 290         /* Avoid the trap.  On smp this this never happens since
 291          * we don't set last_task_used_altivec -- Cort
 292          */
 293         if (new->thread.regs && last_task_used_altivec == new)
 294                 new->thread.regs->msr |= MSR_VEC;
 295 #ifdef CONFIG_SPE
 296         /* Avoid the trap.  On smp this this never happens since
 297          * we don't set last_task_used_spe
 298          */
 299         if (new->thread.regs && last_task_used_spe == new)
 300                 new->thread.regs->msr |= MSR_SPE;
 301 #endif /* CONFIG_SPE */
 302         new_thread = &new->thread;
 303         old_thread = &current->thread;
 304         last = _switch(old_thread, new_thread);
 305         local_irq_restore(s);
 306         return last;
 307 }
 308
 309 void show_regs(struct pt_regs * regs)
 310 {
 311         int i, trap;
 312
 313         printk("NIP: %08lX LR: %08lX SP: %08lX REGS: %p TRAP: %04lx    %s\n",
 314                regs->nip, regs->link, regs->gpr[1], regs, regs->trap,
 315                print_tainted());
 316         printk("MSR: %08lx EE: %01x PR: %01x FP: %01x ME: %01x IR/DR: %01x%01x\n",
 317                regs->msr, regs->msr&MSR_EE ? 1 : 0, regs->msr&MSR_PR ? 1 : 0,
 318                regs->msr & MSR_FP ? 1 : 0,regs->msr&MSR_ME ? 1 : 0,
 319                regs->msr&MSR_IR ? 1 : 0,
 320                regs->msr&MSR_DR ? 1 : 0);
 321         trap = TRAP(regs);
 322         if (trap == 0x300 || trap == 0x600)
 323                 printk("DAR: %08lX, DSISR: %08lX\n", regs->dar, regs->dsisr);
 324         printk("TASK = %p[%d] '%s' THREAD: %p\n",
 325                current, current->pid, current->comm, current->thread_info);
 326         printk("Last syscall: %ld ", current->thread.last_syscall);
 327
 328 #if defined(CONFIG_4xx) && defined(DCRN_PLB0_BEAR)
 329         printk("\nPLB0: bear= 0x%8.8x acr=   0x%8.8x besr=  0x%8.8x\n",
 330             mfdcr(DCRN_PLB0_BEAR), mfdcr(DCRN_PLB0_ACR),
 331             mfdcr(DCRN_PLB0_BESR));
 332 #endif
 333 #if defined(CONFIG_4xx) && defined(DCRN_POB0_BEAR)
 334         printk("PLB0 to OPB: bear= 0x%8.8x besr0= 0x%8.8x besr1= 0x%8.8x\n",
 335             mfdcr(DCRN_POB0_BEAR), mfdcr(DCRN_POB0_BESR0),
 336             mfdcr(DCRN_POB0_BESR1));
 337 #endif
 338
 339 #ifdef CONFIG_SMP
 340         printk(" CPU: %d", smp_processor_id());
 341 #endif /* CONFIG_SMP */
 342
 343         for (i = 0;  i < 32;  i++) {
 344                 long r;
 345                 if ((i % 8) == 0)
 346                         printk("\n" KERN_INFO "GPR%02d: ", i);
 347                 if (__get_user(r, &regs->gpr[i]))
 348                         break;
 349                 printk("%08lX ", r);
 350                 if (i == 12 && !FULL_REGS(regs))
 351                         break;
 352         }
 353         printk("\n");
 354 #ifdef CONFIG_KALLSYMS
 355         /*
 356          * Lookup NIP late so we have the best change of getting the
 357          * above info out without failing
 358          */
 359         printk("NIP [%08lx] ", regs->nip);
 360         print_symbol("%s\n", regs->nip);
 361         printk("LR [%08lx] ", regs->link);
 362         print_symbol("%s\n", regs->link);
 363 #endif
 364         show_stack(current, (unsigned long *) regs->gpr[1]);
 365 }
 366
 367 void exit_thread(void)
 368 {
 369         if (last_task_used_math == current)
 370                 last_task_used_math = NULL;
 371         if (last_task_used_altivec == current)
 372                 last_task_used_altivec = NULL;
 373 #ifdef CONFIG_SPE
 374         if (last_task_used_spe == current)
 375                 last_task_used_spe = NULL;
 376 #endif
 377 }
 378
 379 void flush_thread(void)
 380 {
 381         if (last_task_used_math == current)
 382                 last_task_used_math = NULL;
 383         if (last_task_used_altivec == current)
 384                 last_task_used_altivec = NULL;
 385 #ifdef CONFIG_SPE
 386         if (last_task_used_spe == current)
 387                 last_task_used_spe = NULL;
 388 #endif
 389 }
 390
 391 void
 392 release_thread(struct task_struct *t)
 393 {
 394 }
 395
 396 /*
 397  * This gets called before we allocate a new thread and copy
 398  * the current task into it.
 399  */
 400 void prepare_to_copy(struct task_struct *tsk)
 401 {
 402         struct pt_regs *regs = tsk->thread.regs;
 403
 404         if (regs == NULL)
 405                 return;
 406         preempt_disable();
 407         if (regs->msr & MSR_FP)
 408                 giveup_fpu(current);
 409 #ifdef CONFIG_ALTIVEC
 410         if (regs->msr & MSR_VEC)
 411                 giveup_altivec(current);
 412 #endif /* CONFIG_ALTIVEC */
 413 #ifdef CONFIG_SPE
 414         if (regs->msr & MSR_SPE)
 415                 giveup_spe(current);
 416 #endif /* CONFIG_SPE */
 417         preempt_enable();
 418 }
 419
 420 /*
 421  * Copy a thread..
 422  */
 423 int
 424 copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 425             unsigned long unused,
 426             struct task_struct *p, struct pt_regs *regs)
 427 {
 428         struct pt_regs *childregs, *kregs;
 429         extern void ret_from_fork(void);
 430         unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
 431         unsigned long childframe;
 432
 433         CHECK_FULL_REGS(regs);
 434         /* Copy registers */
 435         sp -= sizeof(struct pt_regs);
 436         childregs = (struct pt_regs *) sp;
 437         *childregs = *regs;
 438         if ((childregs->msr & MSR_PR) == 0) {
 439                 /* for kernel thread, set `current' and stackptr in new task */
 440                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 441                 childregs->gpr[2] = (unsigned long) p;
 442                 p->thread.regs = NULL;  /* no user register state */
 443         } else {
 444                 childregs->gpr[1] = usp;
 445                 p->thread.regs = childregs;
 446                 if (clone_flags & CLONE_SETTLS)
 447                         childregs->gpr[2] = childregs->gpr[6];
 448         }
 449         childregs->gpr[3] = 0;  /* Result from fork() */
 450         sp -= STACK_FRAME_OVERHEAD;
 451         childframe = sp;
 452
 453         /*
 454          * The way this works is that at some point in the future
 455          * some task will call _switch to switch to the new task.
 456          * That will pop off the stack frame created below and start
 457          * the new task running at ret_from_fork.  The new task will
 458          * do some house keeping and then return from the fork or clone
 459          * system call, using the stack frame created above.
 460          */
 461         sp -= sizeof(struct pt_regs);
 462         kregs = (struct pt_regs *) sp;
 463         sp -= STACK_FRAME_OVERHEAD;
 464         p->thread.ksp = sp;
 465         kregs->nip = (unsigned long)ret_from_fork;
 466
 467         p->thread.last_syscall = -1;
 468
 469         return 0;
 470 }
 471
 472 /*
 473  * Set up a thread for executing a new program
 474  */
 475 void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp)
 476 {
 477         set_fs(USER_DS);
 478         memset(regs->gpr, 0, sizeof(regs->gpr));
 479         regs->ctr = 0;
 480         regs->link = 0;
 481         regs->xer = 0;
 482         regs->ccr = 0;
 483         regs->mq = 0;
 484         regs->nip = nip;
 485         regs->gpr[1] = sp;
 486         regs->msr = MSR_USER;
 487         if (last_task_used_math == current)
 488                 last_task_used_math = NULL;
 489         if (last_task_used_altivec == current)
 490                 last_task_used_altivec = NULL;
 491 #ifdef CONFIG_SPE
 492         if (last_task_used_spe == current)
 493                 last_task_used_spe = NULL;
 494 #endif
 495         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 496         current->thread.fpscr = 0;
 497 #ifdef CONFIG_ALTIVEC
 498         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 499         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 500         current->thread.vrsave = 0;
 501         current->thread.used_vr = 0;
 502 #endif /* CONFIG_ALTIVEC */
 503 #ifdef CONFIG_SPE
 504         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 505         current->thread.acc = 0;
 506         current->thread.spefscr = 0;
 507         current->thread.used_spe = 0;
 508 #endif /* CONFIG_SPE */
 509 }
 510
 511 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 512                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 513
 514 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 515 {
 516         struct pt_regs *regs = tsk->thread.regs;
 517
 518         /* This is a bit hairy.  If we are an SPE enabled  processor
 519          * (have embedded fp) we store the IEEE exception enable flags in
 520          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 521          * mode (asyn, precise, disabled) for 'Classic' FP. */
 522         if (val & PR_FP_EXC_SW_ENABLE) {
 523 #ifdef CONFIG_SPE
 524                 tsk->thread.fpexc_mode = val &
 525                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 526 #else
 527                 return -EINVAL;
 528 #endif
 529         } else {
 530                 /* on a CONFIG_SPE this does not hurt us.  The bits that
 531                  * __pack_fe01 use do not overlap with bits used for
 532                  * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 533                  * on CONFIG_SPE implementations are reserved so writing to
 534                  * them does not change anything */
 535                 if (val > PR_FP_EXC_PRECISE)
 536                         return -EINVAL;
 537                 tsk->thread.fpexc_mode = __pack_fe01(val);
 538                 if (regs != NULL && (regs->msr & MSR_FP) != 0)
 539                         regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 540                                 | tsk->thread.fpexc_mode;
 541         }
 542         return 0;
 543 }
 544
 545 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 546 {
 547         unsigned int val;
 548
 549         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 550 #ifdef CONFIG_SPE
 551                 val = tsk->thread.fpexc_mode;
 552 #else
 553                 return -EINVAL;
 554 #endif
 555         else
 556                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 557         return put_user(val, (unsigned int __user *) adr);
 558 }
 559
 560 int sys_clone(unsigned long clone_flags, unsigned long usp,
 561               int __user *parent_tidp, void __user *child_threadptr,
 562               int __user *child_tidp, int p6,
 563               struct pt_regs *regs)
 564 {
 565         CHECK_FULL_REGS(regs);
 566         if (usp == 0)
 567                 usp = regs->gpr[1];     /* stack pointer for child */
 568         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 569 }
 570
 571 int sys_fork(int p1, int p2, int p3, int p4, int p5, int p6,
 572              struct pt_regs *regs)
 573 {
 574         CHECK_FULL_REGS(regs);
 575         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 576 }
 577
 578 int sys_vfork(int p1, int p2, int p3, int p4, int p5, int p6,
 579               struct pt_regs *regs)
 580 {
 581         CHECK_FULL_REGS(regs);
 582         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 583                         regs, 0, NULL, NULL);
 584 }
 585
 586 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 587                unsigned long a3, unsigned long a4, unsigned long a5,
 588                struct pt_regs *regs)
 589 {
 590         int error;
 591         char * filename;
 592
 593         filename = getname((char __user *) a0);
 594         error = PTR_ERR(filename);
 595         if (IS_ERR(filename))
 596                 goto out;
 597         preempt_disable();
 598         if (regs->msr & MSR_FP)
 599                 giveup_fpu(current);
 600 #ifdef CONFIG_ALTIVEC
 601         if (regs->msr & MSR_VEC)
 602                 giveup_altivec(current);
 603 #endif /* CONFIG_ALTIVEC */
 604 #ifdef CONFIG_SPE
 605         if (regs->msr & MSR_SPE)
 606                 giveup_spe(current);
 607 #endif /* CONFIG_SPE */
 608         preempt_enable();
 609         error = do_execve(filename, (char __user *__user *) a1,
 610                           (char __user *__user *) a2, regs);
 611         if (error == 0) {
 612                 task_lock(current);
 613                 current->ptrace &= ~PT_DTRACE;
 614                 task_unlock(current);
 615         }
 616         putname(filename);
 617 out:
 618         return error;
 619 }
 620
 621 void dump_stack(void)
 622 {
 623         show_stack(current, NULL);
 624 }
 625
 626 EXPORT_SYMBOL(dump_stack);
 627
 628 void show_stack(struct task_struct *tsk, unsigned long *stack)
 629 {
 630         unsigned long sp, stack_top, prev_sp, ret;
 631         int count = 0;
 632         unsigned long next_exc = 0;
 633         struct pt_regs *regs;
 634         extern char ret_from_except, ret_from_except_full, ret_from_syscall;
 635
 636         sp = (unsigned long) stack;
 637         if (tsk == NULL)
 638                 tsk = current;
 639         if (sp == 0) {
 640                 if (tsk == current)
 641                         asm("mr %0,1" : "=r" (sp));
 642                 else
 643                         sp = tsk->thread.ksp;
 644         }
 645
 646         prev_sp = (unsigned long) (tsk->thread_info + 1);
 647         stack_top = (unsigned long) tsk->thread_info + THREAD_SIZE;
 648         while (count < 16 && sp > prev_sp && sp < stack_top && (sp & 3) == 0) {
 649                 if (count == 0) {
 650                         printk("Call trace:");
 651 #ifdef CONFIG_KALLSYMS
 652                         printk("\n");
 653 #endif
 654                 } else {
 655                         if (next_exc) {
 656                                 ret = next_exc;
 657                                 next_exc = 0;
 658                         } else
 659                                 ret = *(unsigned long *)(sp + 4);
 660                         printk(" [%08lx] ", ret);
 661 #ifdef CONFIG_KALLSYMS
 662                         print_symbol("%s", ret);
 663                         printk("\n");
 664 #endif
 665                         if (ret == (unsigned long) &ret_from_except
 666                             || ret == (unsigned long) &ret_from_except_full
 667                             || ret == (unsigned long) &ret_from_syscall) {
 668                                 /* sp + 16 points to an exception frame */
 669                                 regs = (struct pt_regs *) (sp + 16);
 670                                 if (sp + 16 + sizeof(*regs) <= stack_top)
 671                                         next_exc = regs->nip;
 672                         }
 673                 }
 674                 ++count;
 675                 sp = *(unsigned long *)sp;
 676         }
 677 #ifndef CONFIG_KALLSYMS
 678         if (count > 0)
 679                 printk("\n");
 680 #endif
 681 }
 682
 683 #if 0
 684 /*
 685  * Low level print for debugging - Cort
 686  */
 687 int __init ll_printk(const char *fmt, ...)
 688 {
 689         va_list args;
 690         char buf[256];
 691         int i;
 692
 693         va_start(args, fmt);
 694         i=vsprintf(buf,fmt,args);
 695         ll_puts(buf);
 696         va_end(args);
 697         return i;
 698 }
 699
 700 int lines = 24, cols = 80;
 701 int orig_x = 0, orig_y = 0;
 702
 703 void puthex(unsigned long val)
 704 {
 705         unsigned char buf[10];
 706         int i;
 707         for (i = 7;  i >= 0;  i--)
 708         {
 709                 buf[i] = "0123456789ABCDEF"[val & 0x0F];
 710                 val >>= 4;
 711         }
 712         buf[8] = '\0';
 713         prom_print(buf);
 714 }
 715
 716 void __init ll_puts(const char *s)
 717 {
 718         int x,y;
 719         char *vidmem = (char *)/*(_ISA_MEM_BASE + 0xB8000) */0xD00B8000;
 720         char c;
 721         extern int mem_init_done;
 722
 723         if ( mem_init_done ) /* assume this means we can printk */
 724         {
 725                 printk(s);
 726                 return;
 727         }
 728
 729 #if 0
 730         if ( have_of )
 731         {
 732                 prom_print(s);
 733                 return;
 734         }
 735 #endif
 736
 737         /*
 738          * can't ll_puts on chrp without openfirmware yet.
 739          * vidmem just needs to be setup for it.
 740          * -- Cort
 741          */
 742         if ( _machine != _MACH_prep )
 743                 return;
 744         x = orig_x;
 745         y = orig_y;
 746
 747         while ( ( c = *s++ ) != '\0' ) {
 748                 if ( c == '\n' ) {
 749                         x = 0;
 750                         if ( ++y >= lines ) {
 751                                 /*scroll();*/
 752                                 /*y--;*/
 753                                 y = 0;
 754                         }
 755                 } else {
 756                         vidmem [ ( x + cols * y ) * 2 ] = c;
 757                         if ( ++x >= cols ) {
 758                                 x = 0;
 759                                 if ( ++y >= lines ) {
 760                                         /*scroll();*/
 761                                         /*y--;*/
 762                                         y = 0;
 763                                 }
 764                         }
 765                 }
 766         }
 767
 768         orig_x = x;
 769         orig_y = y;
 770 }
 771 #endif
 772
 773 unsigned long get_wchan(struct task_struct *p)
 774 {
 775         unsigned long ip, sp;
 776         unsigned long stack_page = (unsigned long) p->thread_info;
 777         int count = 0;
 778         if (!p || p == current || p->state == TASK_RUNNING)
 779                 return 0;
 780         sp = p->thread.ksp;
 781         do {
 782                 sp = *(unsigned long *)sp;
 783                 if (sp < stack_page || sp >= stack_page + 8188)
 784                         return 0;
 785                 if (count > 0) {
 786                         ip = *(unsigned long *)(sp + 4);
 787                         if (!in_sched_functions(ip))
 788                                 return ip;
 789                 }
 790         } while (count++ < 16);
 791         return 0;
 792 }