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 /*
 156  * Make sure the floating-point register state in the
 157  * the thread_struct is up to date for task tsk.
 158  */
 159 void flush_fp_to_thread(struct task_struct *tsk)
 160 {
 161         if (tsk->thread.regs) {
 162                 /*
 163                  * We need to disable preemption here because if we didn't,
 164                  * another process could get scheduled after the regs->msr
 165                  * test but before we have finished saving the FP registers
 166                  * to the thread_struct.  That process could take over the
 167                  * FPU, and then when we get scheduled again we would store
 168                  * bogus values for the remaining FP registers.
 169                  */
 170                 preempt_disable();
 171                 if (tsk->thread.regs->msr & MSR_FP) {
 172 #ifdef CONFIG_SMP
 173                         /*
 174                          * This should only ever be called for current or
 175                          * for a stopped child process.  Since we save away
 176                          * the FP register state on context switch on SMP,
 177                          * there is something wrong if a stopped child appears
 178                          * to still have its FP state in the CPU registers.
 179                          */
 180                         BUG_ON(tsk != current);
 181 #endif
 182                         giveup_fpu(current);
 183                 }
 184                 preempt_enable();
 185         }
 186 }
 187
 188 void enable_kernel_fp(void)
 189 {
 190         WARN_ON(preemptible());
 191
 192 #ifdef CONFIG_SMP
 193         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 194                 giveup_fpu(current);
 195         else
 196                 giveup_fpu(NULL);       /* just enables FP for kernel */
 197 #else
 198         giveup_fpu(last_task_used_math);
 199 #endif /* CONFIG_SMP */
 200 }
 201 EXPORT_SYMBOL(enable_kernel_fp);
 202
 203 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
 204 {
 205         preempt_disable();
 206         if (tsk->thread.regs && (tsk->thread.regs->msr & MSR_FP))
 207                 giveup_fpu(tsk);
 208         preempt_enable();
 209         memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
 210         return 1;
 211 }
 212
 213 #ifdef CONFIG_ALTIVEC
 214 void enable_kernel_altivec(void)
 215 {
 216         WARN_ON(preemptible());
 217
 218 #ifdef CONFIG_SMP
 219         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 220                 giveup_altivec(current);
 221         else
 222                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 223 #else
 224         giveup_altivec(last_task_used_altivec);
 225 #endif /* __SMP __ */
 226 }
 227 EXPORT_SYMBOL(enable_kernel_altivec);
 228
 229 /*
 230  * Make sure the VMX/Altivec register state in the
 231  * the thread_struct is up to date for task tsk.
 232  */
 233 void flush_altivec_to_thread(struct task_struct *tsk)
 234 {
 235         if (tsk->thread.regs) {
 236                 preempt_disable();
 237                 if (tsk->thread.regs->msr & MSR_VEC) {
 238 #ifdef CONFIG_SMP
 239                         BUG_ON(tsk != current);
 240 #endif
 241                         giveup_altivec(current);
 242                 }
 243                 preempt_enable();
 244         }
 245 }
 246
 247 int dump_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
 248 {
 249         if (regs->msr & MSR_VEC)
 250                 giveup_altivec(current);
 251         memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
 252         return 1;
 253 }
 254 #endif /* CONFIG_ALTIVEC */
 255
 256 #ifdef CONFIG_SPE
 257 void
 258 enable_kernel_spe(void)
 259 {
 260         WARN_ON(preemptible());
 261
 262 #ifdef CONFIG_SMP
 263         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 264                 giveup_spe(current);
 265         else
 266                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 267 #else
 268         giveup_spe(last_task_used_spe);
 269 #endif /* __SMP __ */
 270 }
 271 EXPORT_SYMBOL(enable_kernel_spe);
 272
 273 void flush_spe_to_thread(struct task_struct *tsk)
 274 {
 275         if (tsk->thread.regs) {
 276                 preempt_disable();
 277                 if (tsk->thread.regs->msr & MSR_SPE) {
 278 #ifdef CONFIG_SMP
 279                         BUG_ON(tsk != current);
 280 #endif
 281                         giveup_spe(current);
 282                 }
 283                 preempt_enable();
 284         }
 285 }
 286
 287 int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 288 {
 289         if (regs->msr & MSR_SPE)
 290                 giveup_spe(current);
 291         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
 292         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
 293         return 1;
 294 }
 295 #endif /* CONFIG_SPE */
 296
 297 struct task_struct *__switch_to(struct task_struct *prev,
 298         struct task_struct *new)
 299 {
 300         struct thread_struct *new_thread, *old_thread;
 301         unsigned long s;
 302         struct task_struct *last;
 303
 304         local_irq_save(s);
 305 #ifdef CHECK_STACK
 306         check_stack(prev);
 307         check_stack(new);
 308 #endif
 309
 310 #ifdef CONFIG_SMP
 311         /* avoid complexity of lazy save/restore of fpu
 312          * by just saving it every time we switch out if
 313          * this task used the fpu during the last quantum.
 314          *
 315          * If it tries to use the fpu again, it'll trap and
 316          * reload its fp regs.  So we don't have to do a restore
 317          * every switch, just a save.
 318          *  -- Cort
 319          */
 320         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 321                 giveup_fpu(prev);
 322 #ifdef CONFIG_ALTIVEC
 323         /*
 324          * If the previous thread used altivec in the last quantum
 325          * (thus changing altivec regs) then save them.
 326          * We used to check the VRSAVE register but not all apps
 327          * set it, so we don't rely on it now (and in fact we need
 328          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 329          *
 330          * On SMP we always save/restore altivec regs just to avoid the
 331          * complexity of changing processors.
 332          *  -- Cort
 333          */
 334         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_VEC)))
 335                 giveup_altivec(prev);
 336 #endif /* CONFIG_ALTIVEC */
 337 #ifdef CONFIG_SPE
 338         /*
 339          * If the previous thread used spe in the last quantum
 340          * (thus changing spe regs) then save them.
 341          *
 342          * On SMP we always save/restore spe regs just to avoid the
 343          * complexity of changing processors.
 344          */
 345         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 346                 giveup_spe(prev);
 347 #endif /* CONFIG_SPE */
 348 #endif /* CONFIG_SMP */
 349
 350 #ifdef CONFIG_ALTIVEC
 351         /* Avoid the trap.  On smp this this never happens since
 352          * we don't set last_task_used_altivec -- Cort
 353          */
 354         if (new->thread.regs && last_task_used_altivec == new)
 355                 new->thread.regs->msr |= MSR_VEC;
 356 #endif
 357 #ifdef CONFIG_SPE
 358         /* Avoid the trap.  On smp this this never happens since
 359          * we don't set last_task_used_spe
 360          */
 361         if (new->thread.regs && last_task_used_spe == new)
 362                 new->thread.regs->msr |= MSR_SPE;
 363 #endif /* CONFIG_SPE */
 364         new_thread = &new->thread;
 365         old_thread = &current->thread;
 366         last = _switch(old_thread, new_thread);
 367         local_irq_restore(s);
 368         return last;
 369 }
 370
 371 void show_regs(struct pt_regs * regs)
 372 {
 373         int i, trap;
 374
 375         printk("NIP: %08lX LR: %08lX SP: %08lX REGS: %p TRAP: %04lx    %s\n",
 376                regs->nip, regs->link, regs->gpr[1], regs, regs->trap,
 377                print_tainted());
 378         printk("MSR: %08lx EE: %01x PR: %01x FP: %01x ME: %01x IR/DR: %01x%01x\n",
 379                regs->msr, regs->msr&MSR_EE ? 1 : 0, regs->msr&MSR_PR ? 1 : 0,
 380                regs->msr & MSR_FP ? 1 : 0,regs->msr&MSR_ME ? 1 : 0,
 381                regs->msr&MSR_IR ? 1 : 0,
 382                regs->msr&MSR_DR ? 1 : 0);
 383         trap = TRAP(regs);
 384         if (trap == 0x300 || trap == 0x600)
 385                 printk("DAR: %08lX, DSISR: %08lX\n", regs->dar, regs->dsisr);
 386         printk("TASK = %p[%d] '%s' THREAD: %p\n",
 387                current, current->pid, current->comm, task_thread_info(current));
 388         printk("Last syscall: %ld ", current->thread.last_syscall);
 389
 390 #ifdef CONFIG_SMP
 391         printk(" CPU: %d", smp_processor_id());
 392 #endif /* CONFIG_SMP */
 393
 394         for (i = 0;  i < 32;  i++) {
 395                 long r;
 396                 if ((i % 8) == 0)
 397                         printk("\n" KERN_INFO "GPR%02d: ", i);
 398                 if (__get_user(r, &regs->gpr[i]))
 399                         break;
 400                 printk("%08lX ", r);
 401                 if (i == 12 && !FULL_REGS(regs))
 402                         break;
 403         }
 404         printk("\n");
 405 #ifdef CONFIG_KALLSYMS
 406         /*
 407          * Lookup NIP late so we have the best change of getting the
 408          * above info out without failing
 409          */
 410         printk("NIP [%08lx] ", regs->nip);
 411         print_symbol("%s\n", regs->nip);
 412         printk("LR [%08lx] ", regs->link);
 413         print_symbol("%s\n", regs->link);
 414 #endif
 415         show_stack(current, (unsigned long *) regs->gpr[1]);
 416 }
 417
 418 void exit_thread(void)
 419 {
 420         preempt_disable();
 421         if (last_task_used_math == current)
 422                 last_task_used_math = NULL;
 423         if (last_task_used_altivec == current)
 424                 last_task_used_altivec = NULL;
 425 #ifdef CONFIG_SPE
 426         if (last_task_used_spe == current)
 427                 last_task_used_spe = NULL;
 428 #endif
 429         preempt_enable();
 430 }
 431
 432 void flush_thread(void)
 433 {
 434         preempt_disable();
 435         if (last_task_used_math == current)
 436                 last_task_used_math = NULL;
 437         if (last_task_used_altivec == current)
 438                 last_task_used_altivec = NULL;
 439 #ifdef CONFIG_SPE
 440         if (last_task_used_spe == current)
 441                 last_task_used_spe = NULL;
 442 #endif
 443         preempt_enable();
 444 }
 445
 446 void
 447 release_thread(struct task_struct *t)
 448 {
 449 }
 450
 451 /*
 452  * This gets called before we allocate a new thread and copy
 453  * the current task into it.
 454  */
 455 void prepare_to_copy(struct task_struct *tsk)
 456 {
 457         struct pt_regs *regs = tsk->thread.regs;
 458
 459         if (regs == NULL)
 460                 return;
 461         preempt_disable();
 462         if (regs->msr & MSR_FP)
 463                 giveup_fpu(current);
 464 #ifdef CONFIG_ALTIVEC
 465         if (regs->msr & MSR_VEC)
 466                 giveup_altivec(current);
 467 #endif /* CONFIG_ALTIVEC */
 468 #ifdef CONFIG_SPE
 469         if (regs->msr & MSR_SPE)
 470                 giveup_spe(current);
 471 #endif /* CONFIG_SPE */
 472         preempt_enable();
 473 }
 474
 475 /*
 476  * Copy a thread..
 477  */
 478 int
 479 copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 480             unsigned long unused,
 481             struct task_struct *p, struct pt_regs *regs)
 482 {
 483         struct pt_regs *childregs, *kregs;
 484         extern void ret_from_fork(void);
 485         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 486         unsigned long childframe;
 487
 488         CHECK_FULL_REGS(regs);
 489         /* Copy registers */
 490         sp -= sizeof(struct pt_regs);
 491         childregs = (struct pt_regs *) sp;
 492         *childregs = *regs;
 493         if ((childregs->msr & MSR_PR) == 0) {
 494                 /* for kernel thread, set `current' and stackptr in new task */
 495                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 496                 childregs->gpr[2] = (unsigned long) p;
 497                 p->thread.regs = NULL;  /* no user register state */
 498         } else {
 499                 childregs->gpr[1] = usp;
 500                 p->thread.regs = childregs;
 501                 if (clone_flags & CLONE_SETTLS)
 502                         childregs->gpr[2] = childregs->gpr[6];
 503         }
 504         childregs->gpr[3] = 0;  /* Result from fork() */
 505         sp -= STACK_FRAME_OVERHEAD;
 506         childframe = sp;
 507
 508         /*
 509          * The way this works is that at some point in the future
 510          * some task will call _switch to switch to the new task.
 511          * That will pop off the stack frame created below and start
 512          * the new task running at ret_from_fork.  The new task will
 513          * do some house keeping and then return from the fork or clone
 514          * system call, using the stack frame created above.
 515          */
 516         sp -= sizeof(struct pt_regs);
 517         kregs = (struct pt_regs *) sp;
 518         sp -= STACK_FRAME_OVERHEAD;
 519         p->thread.ksp = sp;
 520         kregs->nip = (unsigned long)ret_from_fork;
 521
 522         p->thread.last_syscall = -1;
 523
 524         return 0;
 525 }
 526
 527 /*
 528  * Set up a thread for executing a new program
 529  */
 530 void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp)
 531 {
 532         set_fs(USER_DS);
 533         memset(regs->gpr, 0, sizeof(regs->gpr));
 534         regs->ctr = 0;
 535         regs->link = 0;
 536         regs->xer = 0;
 537         regs->ccr = 0;
 538         regs->mq = 0;
 539         regs->nip = nip;
 540         regs->gpr[1] = sp;
 541         regs->msr = MSR_USER;
 542         preempt_disable();
 543         if (last_task_used_math == current)
 544                 last_task_used_math = NULL;
 545         if (last_task_used_altivec == current)
 546                 last_task_used_altivec = NULL;
 547 #ifdef CONFIG_SPE
 548         if (last_task_used_spe == current)
 549                 last_task_used_spe = NULL;
 550 #endif
 551         preempt_enable();
 552         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 553         current->thread.fpscr.val = 0;
 554 #ifdef CONFIG_ALTIVEC
 555         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 556         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 557         current->thread.vrsave = 0;
 558         current->thread.used_vr = 0;
 559 #endif /* CONFIG_ALTIVEC */
 560 #ifdef CONFIG_SPE
 561         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 562         current->thread.acc = 0;
 563         current->thread.spefscr = 0;
 564         current->thread.used_spe = 0;
 565 #endif /* CONFIG_SPE */
 566 }
 567
 568 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 569                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 570
 571 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 572 {
 573         struct pt_regs *regs = tsk->thread.regs;
 574
 575         /* This is a bit hairy.  If we are an SPE enabled  processor
 576          * (have embedded fp) we store the IEEE exception enable flags in
 577          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 578          * mode (asyn, precise, disabled) for 'Classic' FP. */
 579         if (val & PR_FP_EXC_SW_ENABLE) {
 580 #ifdef CONFIG_SPE
 581                 tsk->thread.fpexc_mode = val &
 582                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 583 #else
 584                 return -EINVAL;
 585 #endif
 586         } else {
 587                 /* on a CONFIG_SPE this does not hurt us.  The bits that
 588                  * __pack_fe01 use do not overlap with bits used for
 589                  * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 590                  * on CONFIG_SPE implementations are reserved so writing to
 591                  * them does not change anything */
 592                 if (val > PR_FP_EXC_PRECISE)
 593                         return -EINVAL;
 594                 tsk->thread.fpexc_mode = __pack_fe01(val);
 595                 if (regs != NULL && (regs->msr & MSR_FP) != 0)
 596                         regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 597                                 | tsk->thread.fpexc_mode;
 598         }
 599         return 0;
 600 }
 601
 602 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 603 {
 604         unsigned int val;
 605
 606         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 607 #ifdef CONFIG_SPE
 608                 val = tsk->thread.fpexc_mode;
 609 #else
 610                 return -EINVAL;
 611 #endif
 612         else
 613                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 614         return put_user(val, (unsigned int __user *) adr);
 615 }
 616
 617 int sys_clone(unsigned long clone_flags, unsigned long usp,
 618               int __user *parent_tidp, void __user *child_threadptr,
 619               int __user *child_tidp, int p6,
 620               struct pt_regs *regs)
 621 {
 622         CHECK_FULL_REGS(regs);
 623         if (usp == 0)
 624                 usp = regs->gpr[1];     /* stack pointer for child */
 625         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 626 }
 627
 628 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 629              unsigned long p4, unsigned long p5, unsigned long p6,
 630              struct pt_regs *regs)
 631 {
 632         CHECK_FULL_REGS(regs);
 633         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 634 }
 635
 636 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 637               unsigned long p4, unsigned long p5, unsigned long p6,
 638               struct pt_regs *regs)
 639 {
 640         CHECK_FULL_REGS(regs);
 641         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 642                         regs, 0, NULL, NULL);
 643 }
 644
 645 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 646                unsigned long a3, unsigned long a4, unsigned long a5,
 647                struct pt_regs *regs)
 648 {
 649         int error;
 650         char * filename;
 651
 652         filename = getname((char __user *) a0);
 653         error = PTR_ERR(filename);
 654         if (IS_ERR(filename))
 655                 goto out;
 656         preempt_disable();
 657         if (regs->msr & MSR_FP)
 658                 giveup_fpu(current);
 659 #ifdef CONFIG_ALTIVEC
 660         if (regs->msr & MSR_VEC)
 661                 giveup_altivec(current);
 662 #endif /* CONFIG_ALTIVEC */
 663 #ifdef CONFIG_SPE
 664         if (regs->msr & MSR_SPE)
 665                 giveup_spe(current);
 666 #endif /* CONFIG_SPE */
 667         preempt_enable();
 668         error = do_execve(filename, (char __user *__user *) a1,
 669                           (char __user *__user *) a2, regs);
 670         if (error == 0) {
 671                 task_lock(current);
 672                 current->ptrace &= ~PT_DTRACE;
 673                 task_unlock(current);
 674         }
 675         putname(filename);
 676 out:
 677         return error;
 678 }
 679
 680 void dump_stack(void)
 681 {
 682         show_stack(current, NULL);
 683 }
 684
 685 EXPORT_SYMBOL(dump_stack);
 686
 687 void show_stack(struct task_struct *tsk, unsigned long *stack)
 688 {
 689         unsigned long sp, stack_top, prev_sp, ret;
 690         int count = 0;
 691         unsigned long next_exc = 0;
 692         struct pt_regs *regs;
 693         extern char ret_from_except, ret_from_except_full, ret_from_syscall;
 694
 695         sp = (unsigned long) stack;
 696         if (tsk == NULL)
 697                 tsk = current;
 698         if (sp == 0) {
 699                 if (tsk == current)
 700                         asm("mr %0,1" : "=r" (sp));
 701                 else
 702                         sp = tsk->thread.ksp;
 703         }
 704
 705         prev_sp = (unsigned long) end_of_stack(tsk);
 706         stack_top = (unsigned long) task_stack_page(tsk) + THREAD_SIZE;
 707         while (count < 16 && sp > prev_sp && sp < stack_top && (sp & 3) == 0) {
 708                 if (count == 0) {
 709                         printk("Call trace:");
 710 #ifdef CONFIG_KALLSYMS
 711                         printk("\n");
 712 #endif
 713                 } else {
 714                         if (next_exc) {
 715                                 ret = next_exc;
 716                                 next_exc = 0;
 717                         } else
 718                                 ret = *(unsigned long *)(sp + 4);
 719                         printk(" [%08lx] ", ret);
 720 #ifdef CONFIG_KALLSYMS
 721                         print_symbol("%s", ret);
 722                         printk("\n");
 723 #endif
 724                         if (ret == (unsigned long) &ret_from_except
 725                             || ret == (unsigned long) &ret_from_except_full
 726                             || ret == (unsigned long) &ret_from_syscall) {
 727                                 /* sp + 16 points to an exception frame */
 728                                 regs = (struct pt_regs *) (sp + 16);
 729                                 if (sp + 16 + sizeof(*regs) <= stack_top)
 730                                         next_exc = regs->nip;
 731                         }
 732                 }
 733                 ++count;
 734                 sp = *(unsigned long *)sp;
 735         }
 736 #ifndef CONFIG_KALLSYMS
 737         if (count > 0)
 738                 printk("\n");
 739 #endif
 740 }
 741
 742 #if 0
 743 /*
 744  * Low level print for debugging - Cort
 745  */
 746 int __init ll_printk(const char *fmt, ...)
 747 {
 748         va_list args;
 749         char buf[256];
 750         int i;
 751
 752         va_start(args, fmt);
 753         i=vsprintf(buf,fmt,args);
 754         ll_puts(buf);
 755         va_end(args);
 756         return i;
 757 }
 758
 759 int lines = 24, cols = 80;
 760 int orig_x = 0, orig_y = 0;
 761
 762 void puthex(unsigned long val)
 763 {
 764         unsigned char buf[10];
 765         int i;
 766         for (i = 7;  i >= 0;  i--)
 767         {
 768                 buf[i] = "0123456789ABCDEF"[val & 0x0F];
 769                 val >>= 4;
 770         }
 771         buf[8] = '\0';
 772         prom_print(buf);
 773 }
 774
 775 void __init ll_puts(const char *s)
 776 {
 777         int x,y;
 778         char *vidmem = (char *)/*(_ISA_MEM_BASE + 0xB8000) */0xD00B8000;
 779         char c;
 780         extern int mem_init_done;
 781
 782         if ( mem_init_done ) /* assume this means we can printk */
 783         {
 784                 printk(s);
 785                 return;
 786         }
 787
 788 #if 0
 789         if ( have_of )
 790         {
 791                 prom_print(s);
 792                 return;
 793         }
 794 #endif
 795
 796         /*
 797          * can't ll_puts on chrp without openfirmware yet.
 798          * vidmem just needs to be setup for it.
 799          * -- Cort
 800          */
 801         if ( _machine != _MACH_prep )
 802                 return;
 803         x = orig_x;
 804         y = orig_y;
 805
 806         while ( ( c = *s++ ) != '\0' ) {
 807                 if ( c == '\n' ) {
 808                         x = 0;
 809                         if ( ++y >= lines ) {
 810                                 /*scroll();*/
 811                                 /*y--;*/
 812                                 y = 0;
 813                         }
 814                 } else {
 815                         vidmem [ ( x + cols * y ) * 2 ] = c;
 816                         if ( ++x >= cols ) {
 817                                 x = 0;
 818                                 if ( ++y >= lines ) {
 819                                         /*scroll();*/
 820                                         /*y--;*/
 821                                         y = 0;
 822                                 }
 823                         }
 824                 }
 825         }
 826
 827         orig_x = x;
 828         orig_y = y;
 829 }
 830 #endif
 831
 832 unsigned long get_wchan(struct task_struct *p)
 833 {
 834         unsigned long ip, sp;
 835         unsigned long stack_page = (unsigned long) task_stack_page(p);
 836         int count = 0;
 837         if (!p || p == current || p->state == TASK_RUNNING)
 838                 return 0;
 839         sp = p->thread.ksp;
 840         do {
 841                 sp = *(unsigned long *)sp;
 842                 if (sp < stack_page || sp >= stack_page + 8188)
 843                         return 0;
 844                 if (count > 0) {
 845                         ip = *(unsigned long *)(sp + 4);
 846                         if (!in_sched_functions(ip))
 847                                 return ip;
 848                 }
 849         } while (count++ < 16);
 850         return 0;
 851 }