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