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 #include <linux/utsname.h>
  40 #include <linux/kprobes.h>
  41
  42 #include <asm/pgtable.h>
  43 #include <asm/uaccess.h>
  44 #include <asm/system.h>
  45 #include <asm/io.h>
  46 #include <asm/processor.h>
  47 #include <asm/mmu.h>
  48 #include <asm/prom.h>
  49 #ifdef CONFIG_PPC64
  50 #include <asm/firmware.h>
  51 #include <asm/plpar_wrappers.h>
  52 #include <asm/time.h>
  53 #endif
  54
  55 extern unsigned long _get_SP(void);
  56
  57 #ifndef CONFIG_SMP
  58 struct task_struct *last_task_used_math = NULL;
  59 struct task_struct *last_task_used_altivec = NULL;
  60 struct task_struct *last_task_used_spe = NULL;
  61 #endif
  62
  63 /*
  64  * Make sure the floating-point register state in the
  65  * the thread_struct is up to date for task tsk.
  66  */
  67 void flush_fp_to_thread(struct task_struct *tsk)
  68 {
  69         if (tsk->thread.regs) {
  70                 /*
  71                  * We need to disable preemption here because if we didn't,
  72                  * another process could get scheduled after the regs->msr
  73                  * test but before we have finished saving the FP registers
  74                  * to the thread_struct.  That process could take over the
  75                  * FPU, and then when we get scheduled again we would store
  76                  * bogus values for the remaining FP registers.
  77                  */
  78                 preempt_disable();
  79                 if (tsk->thread.regs->msr & MSR_FP) {
  80 #ifdef CONFIG_SMP
  81                         /*
  82                          * This should only ever be called for current or
  83                          * for a stopped child process.  Since we save away
  84                          * the FP register state on context switch on SMP,
  85                          * there is something wrong if a stopped child appears
  86                          * to still have its FP state in the CPU registers.
  87                          */
  88                         BUG_ON(tsk != current);
  89 #endif
  90                         giveup_fpu(current);
  91                 }
  92                 preempt_enable();
  93         }
  94 }
  95
  96 void enable_kernel_fp(void)
  97 {
  98         WARN_ON(preemptible());
  99
 100 #ifdef CONFIG_SMP
 101         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 102                 giveup_fpu(current);
 103         else
 104                 giveup_fpu(NULL);       /* just enables FP for kernel */
 105 #else
 106         giveup_fpu(last_task_used_math);
 107 #endif /* CONFIG_SMP */
 108 }
 109 EXPORT_SYMBOL(enable_kernel_fp);
 110
 111 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
 112 {
 113         if (!tsk->thread.regs)
 114                 return 0;
 115         flush_fp_to_thread(current);
 116
 117         memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
 118
 119         return 1;
 120 }
 121
 122 #ifdef CONFIG_ALTIVEC
 123 void enable_kernel_altivec(void)
 124 {
 125         WARN_ON(preemptible());
 126
 127 #ifdef CONFIG_SMP
 128         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 129                 giveup_altivec(current);
 130         else
 131                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 132 #else
 133         giveup_altivec(last_task_used_altivec);
 134 #endif /* CONFIG_SMP */
 135 }
 136 EXPORT_SYMBOL(enable_kernel_altivec);
 137
 138 /*
 139  * Make sure the VMX/Altivec register state in the
 140  * the thread_struct is up to date for task tsk.
 141  */
 142 void flush_altivec_to_thread(struct task_struct *tsk)
 143 {
 144         if (tsk->thread.regs) {
 145                 preempt_disable();
 146                 if (tsk->thread.regs->msr & MSR_VEC) {
 147 #ifdef CONFIG_SMP
 148                         BUG_ON(tsk != current);
 149 #endif
 150                         giveup_altivec(current);
 151                 }
 152                 preempt_enable();
 153         }
 154 }
 155
 156 int dump_task_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
 157 {
 158         flush_altivec_to_thread(current);
 159         memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
 160         return 1;
 161 }
 162 #endif /* CONFIG_ALTIVEC */
 163
 164 #ifdef CONFIG_SPE
 165
 166 void enable_kernel_spe(void)
 167 {
 168         WARN_ON(preemptible());
 169
 170 #ifdef CONFIG_SMP
 171         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 172                 giveup_spe(current);
 173         else
 174                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 175 #else
 176         giveup_spe(last_task_used_spe);
 177 #endif /* __SMP __ */
 178 }
 179 EXPORT_SYMBOL(enable_kernel_spe);
 180
 181 void flush_spe_to_thread(struct task_struct *tsk)
 182 {
 183         if (tsk->thread.regs) {
 184                 preempt_disable();
 185                 if (tsk->thread.regs->msr & MSR_SPE) {
 186 #ifdef CONFIG_SMP
 187                         BUG_ON(tsk != current);
 188 #endif
 189                         giveup_spe(current);
 190                 }
 191                 preempt_enable();
 192         }
 193 }
 194
 195 int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 196 {
 197         flush_spe_to_thread(current);
 198         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
 199         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
 200         return 1;
 201 }
 202 #endif /* CONFIG_SPE */
 203
 204 static void set_dabr_spr(unsigned long val)
 205 {
 206         mtspr(SPRN_DABR, val);
 207 }
 208
 209 int set_dabr(unsigned long dabr)
 210 {
 211         int ret = 0;
 212
 213 #ifdef CONFIG_PPC64
 214         if (firmware_has_feature(FW_FEATURE_XDABR)) {
 215                 /* We want to catch accesses from kernel and userspace */
 216                 unsigned long flags = H_DABRX_KERNEL|H_DABRX_USER;
 217                 ret = plpar_set_xdabr(dabr, flags);
 218         } else if (firmware_has_feature(FW_FEATURE_DABR)) {
 219                 ret = plpar_set_dabr(dabr);
 220         } else
 221 #endif
 222                 set_dabr_spr(dabr);
 223
 224         return ret;
 225 }
 226
 227 #ifdef CONFIG_PPC64
 228 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 229 static DEFINE_PER_CPU(unsigned long, current_dabr);
 230 #endif
 231
 232 struct task_struct *__switch_to(struct task_struct *prev,
 233         struct task_struct *new)
 234 {
 235         struct thread_struct *new_thread, *old_thread;
 236         unsigned long flags;
 237         struct task_struct *last;
 238
 239 #ifdef CONFIG_SMP
 240         /* avoid complexity of lazy save/restore of fpu
 241          * by just saving it every time we switch out if
 242          * this task used the fpu during the last quantum.
 243          *
 244          * If it tries to use the fpu again, it'll trap and
 245          * reload its fp regs.  So we don't have to do a restore
 246          * every switch, just a save.
 247          *  -- Cort
 248          */
 249         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 250                 giveup_fpu(prev);
 251 #ifdef CONFIG_ALTIVEC
 252         /*
 253          * If the previous thread used altivec in the last quantum
 254          * (thus changing altivec regs) then save them.
 255          * We used to check the VRSAVE register but not all apps
 256          * set it, so we don't rely on it now (and in fact we need
 257          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 258          *
 259          * On SMP we always save/restore altivec regs just to avoid the
 260          * complexity of changing processors.
 261          *  -- Cort
 262          */
 263         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 264                 giveup_altivec(prev);
 265 #endif /* CONFIG_ALTIVEC */
 266 #ifdef CONFIG_SPE
 267         /*
 268          * If the previous thread used spe in the last quantum
 269          * (thus changing spe regs) then save them.
 270          *
 271          * On SMP we always save/restore spe regs just to avoid the
 272          * complexity of changing processors.
 273          */
 274         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 275                 giveup_spe(prev);
 276 #endif /* CONFIG_SPE */
 277
 278 #else  /* CONFIG_SMP */
 279 #ifdef CONFIG_ALTIVEC
 280         /* Avoid the trap.  On smp this this never happens since
 281          * we don't set last_task_used_altivec -- Cort
 282          */
 283         if (new->thread.regs && last_task_used_altivec == new)
 284                 new->thread.regs->msr |= MSR_VEC;
 285 #endif /* CONFIG_ALTIVEC */
 286 #ifdef CONFIG_SPE
 287         /* Avoid the trap.  On smp this this never happens since
 288          * we don't set last_task_used_spe
 289          */
 290         if (new->thread.regs && last_task_used_spe == new)
 291                 new->thread.regs->msr |= MSR_SPE;
 292 #endif /* CONFIG_SPE */
 293
 294 #endif /* CONFIG_SMP */
 295
 296 #ifdef CONFIG_PPC64     /* for now */
 297         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
 298                 set_dabr(new->thread.dabr);
 299                 __get_cpu_var(current_dabr) = new->thread.dabr;
 300         }
 301
 302         flush_tlb_pending();
 303 #endif
 304
 305         new_thread = &new->thread;
 306         old_thread = &current->thread;
 307
 308 #ifdef CONFIG_PPC64
 309         /*
 310          * Collect processor utilization data per process
 311          */
 312         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 313                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 314                 long unsigned start_tb, current_tb;
 315                 start_tb = old_thread->start_tb;
 316                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 317                 old_thread->accum_tb += (current_tb - start_tb);
 318                 new_thread->start_tb = current_tb;
 319         }
 320 #endif
 321
 322         local_irq_save(flags);
 323         last = _switch(old_thread, new_thread);
 324
 325         local_irq_restore(flags);
 326
 327         return last;
 328 }
 329
 330 static int instructions_to_print = 16;
 331
 332 #ifdef CONFIG_PPC64
 333 #define BAD_PC(pc)      ((REGION_ID(pc) != KERNEL_REGION_ID) && \
 334                          (REGION_ID(pc) != VMALLOC_REGION_ID))
 335 #else
 336 #define BAD_PC(pc)      ((pc) < KERNELBASE)
 337 #endif
 338
 339 static void show_instructions(struct pt_regs *regs)
 340 {
 341         int i;
 342         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 343                         sizeof(int));
 344
 345         printk("Instruction dump:");
 346
 347         for (i = 0; i < instructions_to_print; i++) {
 348                 int instr;
 349
 350                 if (!(i % 8))
 351                         printk("\n");
 352
 353                 if (BAD_PC(pc) || __get_user(instr, (unsigned int *)pc)) {
 354                         printk("XXXXXXXX ");
 355                 } else {
 356                         if (regs->nip == pc)
 357                                 printk("<%08x> ", instr);
 358                         else
 359                                 printk("%08x ", instr);
 360                 }
 361
 362                 pc += sizeof(int);
 363         }
 364
 365         printk("\n");
 366 }
 367
 368 static struct regbit {
 369         unsigned long bit;
 370         const char *name;
 371 } msr_bits[] = {
 372         {MSR_EE,        "EE"},
 373         {MSR_PR,        "PR"},
 374         {MSR_FP,        "FP"},
 375         {MSR_ME,        "ME"},
 376         {MSR_IR,        "IR"},
 377         {MSR_DR,        "DR"},
 378         {0,             NULL}
 379 };
 380
 381 static void printbits(unsigned long val, struct regbit *bits)
 382 {
 383         const char *sep = "";
 384
 385         printk("<");
 386         for (; bits->bit; ++bits)
 387                 if (val & bits->bit) {
 388                         printk("%s%s", sep, bits->name);
 389                         sep = ",";
 390                 }
 391         printk(">");
 392 }
 393
 394 #ifdef CONFIG_PPC64
 395 #define REG             "%016lX"
 396 #define REGS_PER_LINE   4
 397 #define LAST_VOLATILE   13
 398 #else
 399 #define REG             "%08lX"
 400 #define REGS_PER_LINE   8
 401 #define LAST_VOLATILE   12
 402 #endif
 403
 404 void show_regs(struct pt_regs * regs)
 405 {
 406         int i, trap;
 407
 408         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 409                regs->nip, regs->link, regs->ctr);
 410         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 411                regs, regs->trap, print_tainted(), system_utsname.release);
 412         printk("MSR: "REG" ", regs->msr);
 413         printbits(regs->msr, msr_bits);
 414         printk("  CR: %08lX  XER: %08lX\n", regs->ccr, regs->xer);
 415         trap = TRAP(regs);
 416         if (trap == 0x300 || trap == 0x600)
 417                 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
 418         printk("TASK = %p[%d] '%s' THREAD: %p",
 419                current, current->pid, current->comm, current->thread_info);
 420
 421 #ifdef CONFIG_SMP
 422         printk(" CPU: %d", smp_processor_id());
 423 #endif /* CONFIG_SMP */
 424
 425         for (i = 0;  i < 32;  i++) {
 426                 if ((i % REGS_PER_LINE) == 0)
 427                         printk("\n" KERN_INFO "GPR%02d: ", i);
 428                 printk(REG " ", regs->gpr[i]);
 429                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 430                         break;
 431         }
 432         printk("\n");
 433 #ifdef CONFIG_KALLSYMS
 434         /*
 435          * Lookup NIP late so we have the best change of getting the
 436          * above info out without failing
 437          */
 438         printk("NIP ["REG"] ", regs->nip);
 439         print_symbol("%s\n", regs->nip);
 440         printk("LR ["REG"] ", regs->link);
 441         print_symbol("%s\n", regs->link);
 442 #endif
 443         show_stack(current, (unsigned long *) regs->gpr[1]);
 444         if (!user_mode(regs))
 445                 show_instructions(regs);
 446 }
 447
 448 void exit_thread(void)
 449 {
 450         kprobe_flush_task(current);
 451
 452 #ifndef CONFIG_SMP
 453         if (last_task_used_math == current)
 454                 last_task_used_math = NULL;
 455 #ifdef CONFIG_ALTIVEC
 456         if (last_task_used_altivec == current)
 457                 last_task_used_altivec = NULL;
 458 #endif /* CONFIG_ALTIVEC */
 459 #ifdef CONFIG_SPE
 460         if (last_task_used_spe == current)
 461                 last_task_used_spe = NULL;
 462 #endif
 463 #endif /* CONFIG_SMP */
 464 }
 465
 466 void flush_thread(void)
 467 {
 468 #ifdef CONFIG_PPC64
 469         struct thread_info *t = current_thread_info();
 470
 471         if (t->flags & _TIF_ABI_PENDING)
 472                 t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
 473 #endif
 474         kprobe_flush_task(current);
 475
 476 #ifndef CONFIG_SMP
 477         if (last_task_used_math == current)
 478                 last_task_used_math = NULL;
 479 #ifdef CONFIG_ALTIVEC
 480         if (last_task_used_altivec == current)
 481                 last_task_used_altivec = NULL;
 482 #endif /* CONFIG_ALTIVEC */
 483 #ifdef CONFIG_SPE
 484         if (last_task_used_spe == current)
 485                 last_task_used_spe = NULL;
 486 #endif
 487 #endif /* CONFIG_SMP */
 488
 489 #ifdef CONFIG_PPC64     /* for now */
 490         if (current->thread.dabr) {
 491                 current->thread.dabr = 0;
 492                 set_dabr(0);
 493         }
 494 #endif
 495 }
 496
 497 void
 498 release_thread(struct task_struct *t)
 499 {
 500 }
 501
 502 /*
 503  * This gets called before we allocate a new thread and copy
 504  * the current task into it.
 505  */
 506 void prepare_to_copy(struct task_struct *tsk)
 507 {
 508         flush_fp_to_thread(current);
 509         flush_altivec_to_thread(current);
 510         flush_spe_to_thread(current);
 511 }
 512
 513 /*
 514  * Copy a thread..
 515  */
 516 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 517                 unsigned long unused, struct task_struct *p,
 518                 struct pt_regs *regs)
 519 {
 520         struct pt_regs *childregs, *kregs;
 521         extern void ret_from_fork(void);
 522         unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
 523
 524         CHECK_FULL_REGS(regs);
 525         /* Copy registers */
 526         sp -= sizeof(struct pt_regs);
 527         childregs = (struct pt_regs *) sp;
 528         *childregs = *regs;
 529         if ((childregs->msr & MSR_PR) == 0) {
 530                 /* for kernel thread, set `current' and stackptr in new task */
 531                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 532 #ifdef CONFIG_PPC32
 533                 childregs->gpr[2] = (unsigned long) p;
 534 #else
 535                 clear_ti_thread_flag(p->thread_info, TIF_32BIT);
 536 #endif
 537                 p->thread.regs = NULL;  /* no user register state */
 538         } else {
 539                 childregs->gpr[1] = usp;
 540                 p->thread.regs = childregs;
 541                 if (clone_flags & CLONE_SETTLS) {
 542 #ifdef CONFIG_PPC64
 543                         if (!test_thread_flag(TIF_32BIT))
 544                                 childregs->gpr[13] = childregs->gpr[6];
 545                         else
 546 #endif
 547                                 childregs->gpr[2] = childregs->gpr[6];
 548                 }
 549         }
 550         childregs->gpr[3] = 0;  /* Result from fork() */
 551         sp -= STACK_FRAME_OVERHEAD;
 552
 553         /*
 554          * The way this works is that at some point in the future
 555          * some task will call _switch to switch to the new task.
 556          * That will pop off the stack frame created below and start
 557          * the new task running at ret_from_fork.  The new task will
 558          * do some house keeping and then return from the fork or clone
 559          * system call, using the stack frame created above.
 560          */
 561         sp -= sizeof(struct pt_regs);
 562         kregs = (struct pt_regs *) sp;
 563         sp -= STACK_FRAME_OVERHEAD;
 564         p->thread.ksp = sp;
 565
 566 #ifdef CONFIG_PPC64
 567         if (cpu_has_feature(CPU_FTR_SLB)) {
 568                 unsigned long sp_vsid = get_kernel_vsid(sp);
 569
 570                 sp_vsid <<= SLB_VSID_SHIFT;
 571                 sp_vsid |= SLB_VSID_KERNEL;
 572                 if (cpu_has_feature(CPU_FTR_16M_PAGE))
 573                         sp_vsid |= SLB_VSID_L;
 574
 575                 p->thread.ksp_vsid = sp_vsid;
 576         }
 577
 578         /*
 579          * The PPC64 ABI makes use of a TOC to contain function
 580          * pointers.  The function (ret_from_except) is actually a pointer
 581          * to the TOC entry.  The first entry is a pointer to the actual
 582          * function.
 583          */
 584         kregs->nip = *((unsigned long *)ret_from_fork);
 585 #else
 586         kregs->nip = (unsigned long)ret_from_fork;
 587         p->thread.last_syscall = -1;
 588 #endif
 589
 590         return 0;
 591 }
 592
 593 /*
 594  * Set up a thread for executing a new program
 595  */
 596 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 597 {
 598         set_fs(USER_DS);
 599
 600         /*
 601          * If we exec out of a kernel thread then thread.regs will not be
 602          * set.  Do it now.
 603          */
 604         if (!current->thread.regs) {
 605                 unsigned long childregs = (unsigned long)current->thread_info +
 606                                                 THREAD_SIZE;
 607                 childregs -= sizeof(struct pt_regs);
 608                 current->thread.regs = (struct pt_regs *)childregs;
 609         }
 610
 611         memset(regs->gpr, 0, sizeof(regs->gpr));
 612         regs->ctr = 0;
 613         regs->link = 0;
 614         regs->xer = 0;
 615         regs->ccr = 0;
 616         regs->gpr[1] = sp;
 617
 618 #ifdef CONFIG_PPC32
 619         regs->mq = 0;
 620         regs->nip = start;
 621         regs->msr = MSR_USER;
 622 #else
 623         if (!test_thread_flag(TIF_32BIT)) {
 624                 unsigned long entry, toc, load_addr = regs->gpr[2];
 625
 626                 /* start is a relocated pointer to the function descriptor for
 627                  * the elf _start routine.  The first entry in the function
 628                  * descriptor is the entry address of _start and the second
 629                  * entry is the TOC value we need to use.
 630                  */
 631                 __get_user(entry, (unsigned long __user *)start);
 632                 __get_user(toc, (unsigned long __user *)start+1);
 633
 634                 /* Check whether the e_entry function descriptor entries
 635                  * need to be relocated before we can use them.
 636                  */
 637                 if (load_addr != 0) {
 638                         entry += load_addr;
 639                         toc   += load_addr;
 640                 }
 641                 regs->nip = entry;
 642                 regs->gpr[2] = toc;
 643                 regs->msr = MSR_USER64;
 644         } else {
 645                 regs->nip = start;
 646                 regs->gpr[2] = 0;
 647                 regs->msr = MSR_USER32;
 648         }
 649 #endif
 650
 651 #ifndef CONFIG_SMP
 652         if (last_task_used_math == current)
 653                 last_task_used_math = NULL;
 654 #ifdef CONFIG_ALTIVEC
 655         if (last_task_used_altivec == current)
 656                 last_task_used_altivec = NULL;
 657 #endif
 658 #ifdef CONFIG_SPE
 659         if (last_task_used_spe == current)
 660                 last_task_used_spe = NULL;
 661 #endif
 662 #endif /* CONFIG_SMP */
 663         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 664         current->thread.fpscr = 0;
 665 #ifdef CONFIG_ALTIVEC
 666         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 667         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 668         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 669         current->thread.vrsave = 0;
 670         current->thread.used_vr = 0;
 671 #endif /* CONFIG_ALTIVEC */
 672 #ifdef CONFIG_SPE
 673         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 674         current->thread.acc = 0;
 675         current->thread.spefscr = 0;
 676         current->thread.used_spe = 0;
 677 #endif /* CONFIG_SPE */
 678 }
 679
 680 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 681                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 682
 683 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 684 {
 685         struct pt_regs *regs = tsk->thread.regs;
 686
 687         /* This is a bit hairy.  If we are an SPE enabled  processor
 688          * (have embedded fp) we store the IEEE exception enable flags in
 689          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 690          * mode (asyn, precise, disabled) for 'Classic' FP. */
 691         if (val & PR_FP_EXC_SW_ENABLE) {
 692 #ifdef CONFIG_SPE
 693                 tsk->thread.fpexc_mode = val &
 694                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 695                 return 0;
 696 #else
 697                 return -EINVAL;
 698 #endif
 699         }
 700
 701         /* on a CONFIG_SPE this does not hurt us.  The bits that
 702          * __pack_fe01 use do not overlap with bits used for
 703          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 704          * on CONFIG_SPE implementations are reserved so writing to
 705          * them does not change anything */
 706         if (val > PR_FP_EXC_PRECISE)
 707                 return -EINVAL;
 708         tsk->thread.fpexc_mode = __pack_fe01(val);
 709         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 710                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 711                         | tsk->thread.fpexc_mode;
 712         return 0;
 713 }
 714
 715 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 716 {
 717         unsigned int val;
 718
 719         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 720 #ifdef CONFIG_SPE
 721                 val = tsk->thread.fpexc_mode;
 722 #else
 723                 return -EINVAL;
 724 #endif
 725         else
 726                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 727         return put_user(val, (unsigned int __user *) adr);
 728 }
 729
 730 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
 731
 732 int sys_clone(unsigned long clone_flags, unsigned long usp,
 733               int __user *parent_tidp, void __user *child_threadptr,
 734               int __user *child_tidp, int p6,
 735               struct pt_regs *regs)
 736 {
 737         CHECK_FULL_REGS(regs);
 738         if (usp == 0)
 739                 usp = regs->gpr[1];     /* stack pointer for child */
 740 #ifdef CONFIG_PPC64
 741         if (test_thread_flag(TIF_32BIT)) {
 742                 parent_tidp = TRUNC_PTR(parent_tidp);
 743                 child_tidp = TRUNC_PTR(child_tidp);
 744         }
 745 #endif
 746         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 747 }
 748
 749 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 750              unsigned long p4, unsigned long p5, unsigned long p6,
 751              struct pt_regs *regs)
 752 {
 753         CHECK_FULL_REGS(regs);
 754         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 755 }
 756
 757 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 758               unsigned long p4, unsigned long p5, unsigned long p6,
 759               struct pt_regs *regs)
 760 {
 761         CHECK_FULL_REGS(regs);
 762         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 763                         regs, 0, NULL, NULL);
 764 }
 765
 766 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 767                unsigned long a3, unsigned long a4, unsigned long a5,
 768                struct pt_regs *regs)
 769 {
 770         int error;
 771         char *filename;
 772
 773         filename = getname((char __user *) a0);
 774         error = PTR_ERR(filename);
 775         if (IS_ERR(filename))
 776                 goto out;
 777         flush_fp_to_thread(current);
 778         flush_altivec_to_thread(current);
 779         flush_spe_to_thread(current);
 780         error = do_execve(filename, (char __user * __user *) a1,
 781                           (char __user * __user *) a2, regs);
 782         if (error == 0) {
 783                 task_lock(current);
 784                 current->ptrace &= ~PT_DTRACE;
 785                 task_unlock(current);
 786         }
 787         putname(filename);
 788 out:
 789         return error;
 790 }
 791
 792 static int validate_sp(unsigned long sp, struct task_struct *p,
 793                        unsigned long nbytes)
 794 {
 795         unsigned long stack_page = (unsigned long)p->thread_info;
 796
 797         if (sp >= stack_page + sizeof(struct thread_struct)
 798             && sp <= stack_page + THREAD_SIZE - nbytes)
 799                 return 1;
 800
 801 #ifdef CONFIG_IRQSTACKS
 802         stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
 803         if (sp >= stack_page + sizeof(struct thread_struct)
 804             && sp <= stack_page + THREAD_SIZE - nbytes)
 805                 return 1;
 806
 807         stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
 808         if (sp >= stack_page + sizeof(struct thread_struct)
 809             && sp <= stack_page + THREAD_SIZE - nbytes)
 810                 return 1;
 811 #endif
 812
 813         return 0;
 814 }
 815
 816 #ifdef CONFIG_PPC64
 817 #define MIN_STACK_FRAME 112     /* same as STACK_FRAME_OVERHEAD, in fact */
 818 #define FRAME_LR_SAVE   2
 819 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
 820 #define REGS_MARKER     0x7265677368657265ul
 821 #define FRAME_MARKER    12
 822 #else
 823 #define MIN_STACK_FRAME 16
 824 #define FRAME_LR_SAVE   1
 825 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
 826 #define REGS_MARKER     0x72656773ul
 827 #define FRAME_MARKER    2
 828 #endif
 829
 830 unsigned long get_wchan(struct task_struct *p)
 831 {
 832         unsigned long ip, sp;
 833         int count = 0;
 834
 835         if (!p || p == current || p->state == TASK_RUNNING)
 836                 return 0;
 837
 838         sp = p->thread.ksp;
 839         if (!validate_sp(sp, p, MIN_STACK_FRAME))
 840                 return 0;
 841
 842         do {
 843                 sp = *(unsigned long *)sp;
 844                 if (!validate_sp(sp, p, MIN_STACK_FRAME))
 845                         return 0;
 846                 if (count > 0) {
 847                         ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
 848                         if (!in_sched_functions(ip))
 849                                 return ip;
 850                 }
 851         } while (count++ < 16);
 852         return 0;
 853 }
 854 EXPORT_SYMBOL(get_wchan);
 855
 856 static int kstack_depth_to_print = 64;
 857
 858 void show_stack(struct task_struct *tsk, unsigned long *stack)
 859 {
 860         unsigned long sp, ip, lr, newsp;
 861         int count = 0;
 862         int firstframe = 1;
 863
 864         sp = (unsigned long) stack;
 865         if (tsk == NULL)
 866                 tsk = current;
 867         if (sp == 0) {
 868                 if (tsk == current)
 869                         asm("mr %0,1" : "=r" (sp));
 870                 else
 871                         sp = tsk->thread.ksp;
 872         }
 873
 874         lr = 0;
 875         printk("Call Trace:\n");
 876         do {
 877                 if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
 878                         return;
 879
 880                 stack = (unsigned long *) sp;
 881                 newsp = stack[0];
 882                 ip = stack[FRAME_LR_SAVE];
 883                 if (!firstframe || ip != lr) {
 884                         printk("["REG"] ["REG"] ", sp, ip);
 885                         print_symbol("%s", ip);
 886                         if (firstframe)
 887                                 printk(" (unreliable)");
 888                         printk("\n");
 889                 }
 890                 firstframe = 0;
 891
 892                 /*
 893                  * See if this is an exception frame.
 894                  * We look for the "regshere" marker in the current frame.
 895                  */
 896                 if (validate_sp(sp, tsk, INT_FRAME_SIZE)
 897                     && stack[FRAME_MARKER] == REGS_MARKER) {
 898                         struct pt_regs *regs = (struct pt_regs *)
 899                                 (sp + STACK_FRAME_OVERHEAD);
 900                         printk("--- Exception: %lx", regs->trap);
 901                         print_symbol(" at %s\n", regs->nip);
 902                         lr = regs->link;
 903                         print_symbol("    LR = %s\n", lr);
 904                         firstframe = 1;
 905                 }
 906
 907                 sp = newsp;
 908         } while (count++ < kstack_depth_to_print);
 909 }
 910
 911 void dump_stack(void)
 912 {
 913         show_stack(current, NULL);
 914 }
 915 EXPORT_SYMBOL(dump_stack);