arch/powerpc/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 #include <linux/config.h>
  20 #include <linux/errno.h>
  21 #include <linux/sched.h>
  22 #include <linux/kernel.h>
  23 #include <linux/mm.h>
  24 #include <linux/smp.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/stddef.h>
  27 #include <linux/unistd.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/slab.h>
  30 #include <linux/user.h>
  31 #include <linux/elf.h>
  32 #include <linux/init.h>
  33 #include <linux/prctl.h>
  34 #include <linux/init_task.h>
  35 #include <linux/module.h>
  36 #include <linux/kallsyms.h>
  37 #include <linux/mqueue.h>
  38 #include <linux/hardirq.h>
  39
  40 #include <asm/pgtable.h>
  41 #include <asm/uaccess.h>
  42 #include <asm/system.h>
  43 #include <asm/io.h>
  44 #include <asm/processor.h>
  45 #include <asm/mmu.h>
  46 #include <asm/prom.h>
  47
  48 extern unsigned long _get_SP(void);
  49
  50 #ifndef CONFIG_SMP
  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 #endif
  55
  56 static struct fs_struct init_fs = INIT_FS;
  57 static struct files_struct init_files = INIT_FILES;
  58 static struct signal_struct init_signals = INIT_SIGNALS(init_signals);
  59 static struct sighand_struct init_sighand = INIT_SIGHAND(init_sighand);
  60 struct mm_struct init_mm = INIT_MM(init_mm);
  61 EXPORT_SYMBOL(init_mm);
  62
  63 /* this is 8kB-aligned so we can get to the thread_info struct
  64    at the base of it from the stack pointer with 1 integer instruction. */
  65 union thread_union init_thread_union
  66         __attribute__((__section__(".data.init_task"))) =
  67 { INIT_THREAD_INFO(init_task) };
  68
  69 /* initial task structure */
  70 struct task_struct init_task = INIT_TASK(init_task);
  71 EXPORT_SYMBOL(init_task);
  72
  73 /* only used to get secondary processor up */
  74 struct task_struct *current_set[NR_CPUS] = {&init_task, };
  75
  76 /*
  77  * Make sure the floating-point register state in the
  78  * the thread_struct is up to date for task tsk.
  79  */
  80 void flush_fp_to_thread(struct task_struct *tsk)
  81 {
  82         if (tsk->thread.regs) {
  83                 /*
  84                  * We need to disable preemption here because if we didn't,
  85                  * another process could get scheduled after the regs->msr
  86                  * test but before we have finished saving the FP registers
  87                  * to the thread_struct.  That process could take over the
  88                  * FPU, and then when we get scheduled again we would store
  89                  * bogus values for the remaining FP registers.
  90                  */
  91                 preempt_disable();
  92                 if (tsk->thread.regs->msr & MSR_FP) {
  93 #ifdef CONFIG_SMP
  94                         /*
  95                          * This should only ever be called for current or
  96                          * for a stopped child process.  Since we save away
  97                          * the FP register state on context switch on SMP,
  98                          * there is something wrong if a stopped child appears
  99                          * to still have its FP state in the CPU registers.
 100                          */
 101                         BUG_ON(tsk != current);
 102 #endif
 103                         giveup_fpu(current);
 104                 }
 105                 preempt_enable();
 106         }
 107 }
 108
 109 void enable_kernel_fp(void)
 110 {
 111         WARN_ON(preemptible());
 112
 113 #ifdef CONFIG_SMP
 114         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 115                 giveup_fpu(current);
 116         else
 117                 giveup_fpu(NULL);       /* just enables FP for kernel */
 118 #else
 119         giveup_fpu(last_task_used_math);
 120 #endif /* CONFIG_SMP */
 121 }
 122 EXPORT_SYMBOL(enable_kernel_fp);
 123
 124 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
 125 {
 126         if (!tsk->thread.regs)
 127                 return 0;
 128         flush_fp_to_thread(current);
 129
 130         memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
 131
 132         return 1;
 133 }
 134
 135 #ifdef CONFIG_ALTIVEC
 136 void enable_kernel_altivec(void)
 137 {
 138         WARN_ON(preemptible());
 139
 140 #ifdef CONFIG_SMP
 141         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 142                 giveup_altivec(current);
 143         else
 144                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 145 #else
 146         giveup_altivec(last_task_used_altivec);
 147 #endif /* CONFIG_SMP */
 148 }
 149 EXPORT_SYMBOL(enable_kernel_altivec);
 150
 151 /*
 152  * Make sure the VMX/Altivec register state in the
 153  * the thread_struct is up to date for task tsk.
 154  */
 155 void flush_altivec_to_thread(struct task_struct *tsk)
 156 {
 157         if (tsk->thread.regs) {
 158                 preempt_disable();
 159                 if (tsk->thread.regs->msr & MSR_VEC) {
 160 #ifdef CONFIG_SMP
 161                         BUG_ON(tsk != current);
 162 #endif
 163                         giveup_altivec(current);
 164                 }
 165                 preempt_enable();
 166         }
 167 }
 168
 169 int dump_task_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
 170 {
 171         flush_altivec_to_thread(current);
 172         memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
 173         return 1;
 174 }
 175 #endif /* CONFIG_ALTIVEC */
 176
 177 #ifdef CONFIG_SPE
 178
 179 void enable_kernel_spe(void)
 180 {
 181         WARN_ON(preemptible());
 182
 183 #ifdef CONFIG_SMP
 184         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 185                 giveup_spe(current);
 186         else
 187                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 188 #else
 189         giveup_spe(last_task_used_spe);
 190 #endif /* __SMP __ */
 191 }
 192 EXPORT_SYMBOL(enable_kernel_spe);
 193
 194 void flush_spe_to_thread(struct task_struct *tsk)
 195 {
 196         if (tsk->thread.regs) {
 197                 preempt_disable();
 198                 if (tsk->thread.regs->msr & MSR_SPE) {
 199 #ifdef CONFIG_SMP
 200                         BUG_ON(tsk != current);
 201 #endif
 202                         giveup_spe(current);
 203                 }
 204                 preempt_enable();
 205         }
 206 }
 207
 208 int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 209 {
 210         flush_spe_to_thread(current);
 211         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
 212         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
 213         return 1;
 214 }
 215 #endif /* CONFIG_SPE */
 216
 217 static void set_dabr_spr(unsigned long val)
 218 {
 219         mtspr(SPRN_DABR, val);
 220 }
 221
 222 int set_dabr(unsigned long dabr)
 223 {
 224         int ret = 0;
 225
 226 #ifdef CONFIG_PPC64
 227         if (firmware_has_feature(FW_FEATURE_XDABR)) {
 228                 /* We want to catch accesses from kernel and userspace */
 229                 unsigned long flags = H_DABRX_KERNEL|H_DABRX_USER;
 230                 ret = plpar_set_xdabr(dabr, flags);
 231         } else if (firmware_has_feature(FW_FEATURE_DABR)) {
 232                 ret = plpar_set_dabr(dabr);
 233         } else
 234 #endif
 235                 set_dabr_spr(dabr);
 236
 237         return ret;
 238 }
 239
 240 static DEFINE_PER_CPU(unsigned long, current_dabr);
 241
 242 struct task_struct *__switch_to(struct task_struct *prev,
 243         struct task_struct *new)
 244 {
 245         struct thread_struct *new_thread, *old_thread;
 246         unsigned long flags;
 247         struct task_struct *last;
 248
 249 #ifdef CONFIG_SMP
 250         /* avoid complexity of lazy save/restore of fpu
 251          * by just saving it every time we switch out if
 252          * this task used the fpu during the last quantum.
 253          *
 254          * If it tries to use the fpu again, it'll trap and
 255          * reload its fp regs.  So we don't have to do a restore
 256          * every switch, just a save.
 257          *  -- Cort
 258          */
 259         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 260                 giveup_fpu(prev);
 261 #ifdef CONFIG_ALTIVEC
 262         /*
 263          * If the previous thread used altivec in the last quantum
 264          * (thus changing altivec regs) then save them.
 265          * We used to check the VRSAVE register but not all apps
 266          * set it, so we don't rely on it now (and in fact we need
 267          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 268          *
 269          * On SMP we always save/restore altivec regs just to avoid the
 270          * complexity of changing processors.
 271          *  -- Cort
 272          */
 273         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 274                 giveup_altivec(prev);
 275 #endif /* CONFIG_ALTIVEC */
 276 #ifdef CONFIG_SPE
 277         /*
 278          * If the previous thread used spe in the last quantum
 279          * (thus changing spe regs) then save them.
 280          *
 281          * On SMP we always save/restore spe regs just to avoid the
 282          * complexity of changing processors.
 283          */
 284         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 285                 giveup_spe(prev);
 286 #endif /* CONFIG_SPE */
 287
 288 #else  /* CONFIG_SMP */
 289 #ifdef CONFIG_ALTIVEC
 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 #endif /* CONFIG_ALTIVEC */
 296 #ifdef CONFIG_SPE
 297         /* Avoid the trap.  On smp this this never happens since
 298          * we don't set last_task_used_spe
 299          */
 300         if (new->thread.regs && last_task_used_spe == new)
 301                 new->thread.regs->msr |= MSR_SPE;
 302 #endif /* CONFIG_SPE */
 303
 304 #endif /* CONFIG_SMP */
 305
 306 #ifdef CONFIG_PPC64     /* for now */
 307         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
 308                 set_dabr(new->thread.dabr);
 309                 __get_cpu_var(current_dabr) = new->thread.dabr;
 310         }
 311 #endif
 312
 313         new_thread = &new->thread;
 314         old_thread = &current->thread;
 315         local_irq_save(flags);
 316         last = _switch(old_thread, new_thread);
 317
 318         local_irq_restore(flags);
 319
 320         return last;
 321 }
 322
 323 void show_regs(struct pt_regs * regs)
 324 {
 325         int i, trap;
 326
 327         printk("NIP: %08lX LR: %08lX SP: %08lX REGS: %p TRAP: %04lx    %s\n",
 328                regs->nip, regs->link, regs->gpr[1], regs, regs->trap,
 329                print_tainted());
 330         printk("MSR: %08lx EE: %01x PR: %01x FP: %01x ME: %01x IR/DR: %01x%01x\n",
 331                regs->msr, regs->msr&MSR_EE ? 1 : 0, regs->msr&MSR_PR ? 1 : 0,
 332                regs->msr & MSR_FP ? 1 : 0,regs->msr&MSR_ME ? 1 : 0,
 333                regs->msr&MSR_IR ? 1 : 0,
 334                regs->msr&MSR_DR ? 1 : 0);
 335         trap = TRAP(regs);
 336         if (trap == 0x300 || trap == 0x600)
 337                 printk("DAR: %08lX, DSISR: %08lX\n", regs->dar, regs->dsisr);
 338         printk("TASK = %p[%d] '%s' THREAD: %p\n",
 339                current, current->pid, current->comm, current->thread_info);
 340         printk("Last syscall: %ld ", current->thread.last_syscall);
 341
 342 #ifdef CONFIG_SMP
 343         printk(" CPU: %d", smp_processor_id());
 344 #endif /* CONFIG_SMP */
 345
 346         for (i = 0;  i < 32;  i++) {
 347                 long r;
 348                 if ((i % 8) == 0)
 349                         printk("\n" KERN_INFO "GPR%02d: ", i);
 350                 if (__get_user(r, &regs->gpr[i]))
 351                         break;
 352                 printk("%08lX ", r);
 353                 if (i == 12 && !FULL_REGS(regs))
 354                         break;
 355         }
 356         printk("\n");
 357 #ifdef CONFIG_KALLSYMS
 358         /*
 359          * Lookup NIP late so we have the best change of getting the
 360          * above info out without failing
 361          */
 362         printk("NIP [%08lx] ", regs->nip);
 363         print_symbol("%s\n", regs->nip);
 364         printk("LR [%08lx] ", regs->link);
 365         print_symbol("%s\n", regs->link);
 366 #endif
 367         show_stack(current, (unsigned long *) regs->gpr[1]);
 368 }
 369
 370 void exit_thread(void)
 371 {
 372 #ifndef CONFIG_SMP
 373         if (last_task_used_math == current)
 374                 last_task_used_math = NULL;
 375 #ifdef CONFIG_ALTIVEC
 376         if (last_task_used_altivec == current)
 377                 last_task_used_altivec = NULL;
 378 #endif /* CONFIG_ALTIVEC */
 379 #ifdef CONFIG_SPE
 380         if (last_task_used_spe == current)
 381                 last_task_used_spe = NULL;
 382 #endif
 383 #endif /* CONFIG_SMP */
 384 }
 385
 386 void flush_thread(void)
 387 {
 388 #ifndef CONFIG_SMP
 389         if (last_task_used_math == current)
 390                 last_task_used_math = NULL;
 391 #ifdef CONFIG_ALTIVEC
 392         if (last_task_used_altivec == current)
 393                 last_task_used_altivec = NULL;
 394 #endif /* CONFIG_ALTIVEC */
 395 #ifdef CONFIG_SPE
 396         if (last_task_used_spe == current)
 397                 last_task_used_spe = NULL;
 398 #endif
 399 #endif /* CONFIG_SMP */
 400
 401 #ifdef CONFIG_PPC64     /* for now */
 402         if (current->thread.dabr) {
 403                 current->thread.dabr = 0;
 404                 set_dabr(0);
 405         }
 406 #endif
 407 }
 408
 409 void
 410 release_thread(struct task_struct *t)
 411 {
 412 }
 413
 414 /*
 415  * This gets called before we allocate a new thread and copy
 416  * the current task into it.
 417  */
 418 void prepare_to_copy(struct task_struct *tsk)
 419 {
 420         flush_fp_to_thread(current);
 421         flush_altivec_to_thread(current);
 422         flush_spe_to_thread(current);
 423 }
 424
 425 /*
 426  * Copy a thread..
 427  */
 428 int
 429 copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 430             unsigned long unused,
 431             struct task_struct *p, struct pt_regs *regs)
 432 {
 433         struct pt_regs *childregs, *kregs;
 434         extern void ret_from_fork(void);
 435         unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
 436         unsigned long childframe;
 437
 438         CHECK_FULL_REGS(regs);
 439         /* Copy registers */
 440         sp -= sizeof(struct pt_regs);
 441         childregs = (struct pt_regs *) sp;
 442         *childregs = *regs;
 443         if ((childregs->msr & MSR_PR) == 0) {
 444                 /* for kernel thread, set `current' and stackptr in new task */
 445                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 446                 childregs->gpr[2] = (unsigned long) p;
 447                 p->thread.regs = NULL;  /* no user register state */
 448         } else {
 449                 childregs->gpr[1] = usp;
 450                 p->thread.regs = childregs;
 451                 if (clone_flags & CLONE_SETTLS)
 452                         childregs->gpr[2] = childregs->gpr[6];
 453         }
 454         childregs->gpr[3] = 0;  /* Result from fork() */
 455         sp -= STACK_FRAME_OVERHEAD;
 456         childframe = sp;
 457
 458         /*
 459          * The way this works is that at some point in the future
 460          * some task will call _switch to switch to the new task.
 461          * That will pop off the stack frame created below and start
 462          * the new task running at ret_from_fork.  The new task will
 463          * do some house keeping and then return from the fork or clone
 464          * system call, using the stack frame created above.
 465          */
 466         sp -= sizeof(struct pt_regs);
 467         kregs = (struct pt_regs *) sp;
 468         sp -= STACK_FRAME_OVERHEAD;
 469         p->thread.ksp = sp;
 470         kregs->nip = (unsigned long)ret_from_fork;
 471
 472         p->thread.last_syscall = -1;
 473
 474         return 0;
 475 }
 476
 477 /*
 478  * Set up a thread for executing a new program
 479  */
 480 void start_thread(struct pt_regs *regs, unsigned long nip, unsigned long sp)
 481 {
 482         set_fs(USER_DS);
 483         memset(regs->gpr, 0, sizeof(regs->gpr));
 484         regs->ctr = 0;
 485         regs->link = 0;
 486         regs->xer = 0;
 487         regs->ccr = 0;
 488         regs->mq = 0;
 489         regs->nip = nip;
 490         regs->gpr[1] = sp;
 491         regs->msr = MSR_USER;
 492 #ifndef CONFIG_SMP
 493         if (last_task_used_math == current)
 494                 last_task_used_math = NULL;
 495 #ifdef CONFIG_ALTIVEC
 496         if (last_task_used_altivec == current)
 497                 last_task_used_altivec = NULL;
 498 #endif
 499 #ifdef CONFIG_SPE
 500         if (last_task_used_spe == current)
 501                 last_task_used_spe = NULL;
 502 #endif
 503 #endif /* CONFIG_SMP */
 504         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 505         current->thread.fpscr = 0;
 506 #ifdef CONFIG_ALTIVEC
 507         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 508         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 509         current->thread.vrsave = 0;
 510         current->thread.used_vr = 0;
 511 #endif /* CONFIG_ALTIVEC */
 512 #ifdef CONFIG_SPE
 513         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 514         current->thread.acc = 0;
 515         current->thread.spefscr = 0;
 516         current->thread.used_spe = 0;
 517 #endif /* CONFIG_SPE */
 518 }
 519
 520 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 521                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 522
 523 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 524 {
 525         struct pt_regs *regs = tsk->thread.regs;
 526
 527         /* This is a bit hairy.  If we are an SPE enabled  processor
 528          * (have embedded fp) we store the IEEE exception enable flags in
 529          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 530          * mode (asyn, precise, disabled) for 'Classic' FP. */
 531         if (val & PR_FP_EXC_SW_ENABLE) {
 532 #ifdef CONFIG_SPE
 533                 tsk->thread.fpexc_mode = val &
 534                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 535 #else
 536                 return -EINVAL;
 537 #endif
 538         } else {
 539                 /* on a CONFIG_SPE this does not hurt us.  The bits that
 540                  * __pack_fe01 use do not overlap with bits used for
 541                  * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 542                  * on CONFIG_SPE implementations are reserved so writing to
 543                  * them does not change anything */
 544                 if (val > PR_FP_EXC_PRECISE)
 545                         return -EINVAL;
 546                 tsk->thread.fpexc_mode = __pack_fe01(val);
 547                 if (regs != NULL && (regs->msr & MSR_FP) != 0)
 548                         regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 549                                 | tsk->thread.fpexc_mode;
 550         }
 551         return 0;
 552 }
 553
 554 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 555 {
 556         unsigned int val;
 557
 558         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 559 #ifdef CONFIG_SPE
 560                 val = tsk->thread.fpexc_mode;
 561 #else
 562                 return -EINVAL;
 563 #endif
 564         else
 565                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 566         return put_user(val, (unsigned int __user *) adr);
 567 }
 568
 569 int sys_clone(unsigned long clone_flags, unsigned long usp,
 570               int __user *parent_tidp, void __user *child_threadptr,
 571               int __user *child_tidp, int p6,
 572               struct pt_regs *regs)
 573 {
 574         CHECK_FULL_REGS(regs);
 575         if (usp == 0)
 576                 usp = regs->gpr[1];     /* stack pointer for child */
 577         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 578 }
 579
 580 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 581              unsigned long p4, unsigned long p5, unsigned long p6,
 582              struct pt_regs *regs)
 583 {
 584         CHECK_FULL_REGS(regs);
 585         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 586 }
 587
 588 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 589               unsigned long p4, unsigned long p5, unsigned long p6,
 590               struct pt_regs *regs)
 591 {
 592         CHECK_FULL_REGS(regs);
 593         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 594                         regs, 0, NULL, NULL);
 595 }
 596
 597 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 598                unsigned long a3, unsigned long a4, unsigned long a5,
 599                struct pt_regs *regs)
 600 {
 601         int error;
 602         char * filename;
 603
 604         filename = getname((char __user *) a0);
 605         error = PTR_ERR(filename);
 606         if (IS_ERR(filename))
 607                 goto out;
 608         flush_fp_to_thread(current);
 609         flush_altivec_to_thread(current);
 610         flush_spe_to_thread(current);
 611         error = do_execve(filename, (char __user * __user *) a1,
 612                           (char __user * __user *) a2, regs);
 613         if (error == 0) {
 614                 task_lock(current);
 615                 current->ptrace &= ~PT_DTRACE;
 616                 task_unlock(current);
 617         }
 618         putname(filename);
 619 out:
 620         return error;
 621 }
 622
 623 static int validate_sp(unsigned long sp, struct task_struct *p,
 624                        unsigned long nbytes)
 625 {
 626         unsigned long stack_page = (unsigned long)p->thread_info;
 627
 628         if (sp >= stack_page + sizeof(struct thread_struct)
 629             && sp <= stack_page + THREAD_SIZE - nbytes)
 630                 return 1;
 631
 632 #ifdef CONFIG_IRQSTACKS
 633         stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
 634         if (sp >= stack_page + sizeof(struct thread_struct)
 635             && sp <= stack_page + THREAD_SIZE - nbytes)
 636                 return 1;
 637
 638         stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
 639         if (sp >= stack_page + sizeof(struct thread_struct)
 640             && sp <= stack_page + THREAD_SIZE - nbytes)
 641                 return 1;
 642 #endif
 643
 644         return 0;
 645 }
 646
 647 void dump_stack(void)
 648 {
 649         show_stack(current, NULL);
 650 }
 651
 652 EXPORT_SYMBOL(dump_stack);
 653
 654 void show_stack(struct task_struct *tsk, unsigned long *stack)
 655 {
 656         unsigned long sp, stack_top, prev_sp, ret;
 657         int count = 0;
 658         unsigned long next_exc = 0;
 659         struct pt_regs *regs;
 660         extern char ret_from_except, ret_from_except_full, ret_from_syscall;
 661
 662         sp = (unsigned long) stack;
 663         if (tsk == NULL)
 664                 tsk = current;
 665         if (sp == 0) {
 666                 if (tsk == current)
 667                         asm("mr %0,1" : "=r" (sp));
 668                 else
 669                         sp = tsk->thread.ksp;
 670         }
 671
 672         prev_sp = (unsigned long) (tsk->thread_info + 1);
 673         stack_top = (unsigned long) tsk->thread_info + THREAD_SIZE;
 674         while (count < 16 && sp > prev_sp && sp < stack_top && (sp & 3) == 0) {
 675                 if (count == 0) {
 676                         printk("Call trace:");
 677 #ifdef CONFIG_KALLSYMS
 678                         printk("\n");
 679 #endif
 680                 } else {
 681                         if (next_exc) {
 682                                 ret = next_exc;
 683                                 next_exc = 0;
 684                         } else
 685                                 ret = *(unsigned long *)(sp + 4);
 686                         printk(" [%08lx] ", ret);
 687 #ifdef CONFIG_KALLSYMS
 688                         print_symbol("%s", ret);
 689                         printk("\n");
 690 #endif
 691                         if (ret == (unsigned long) &ret_from_except
 692                             || ret == (unsigned long) &ret_from_except_full
 693                             || ret == (unsigned long) &ret_from_syscall) {
 694                                 /* sp + 16 points to an exception frame */
 695                                 regs = (struct pt_regs *) (sp + 16);
 696                                 if (sp + 16 + sizeof(*regs) <= stack_top)
 697                                         next_exc = regs->nip;
 698                         }
 699                 }
 700                 ++count;
 701                 sp = *(unsigned long *)sp;
 702         }
 703 #ifndef CONFIG_KALLSYMS
 704         if (count > 0)
 705                 printk("\n");
 706 #endif
 707 }
 708
 709 unsigned long get_wchan(struct task_struct *p)
 710 {
 711         unsigned long ip, sp;
 712         int count = 0;
 713
 714         if (!p || p == current || p->state == TASK_RUNNING)
 715                 return 0;
 716
 717         sp = p->thread.ksp;
 718         if (!validate_sp(sp, p, 16))
 719                 return 0;
 720
 721         do {
 722                 sp = *(unsigned long *)sp;
 723                 if (!validate_sp(sp, p, 16))
 724                         return 0;
 725                 if (count > 0) {
 726                         ip = *(unsigned long *)(sp + 4);
 727                         if (!in_sched_functions(ip))
 728                                 return ip;
 729                 }
 730         } while (count++ < 16);
 731         return 0;
 732 }
 733 EXPORT_SYMBOL(get_wchan);