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