arch/powerpc/kernel/process.c

   1 /*
   2  *  Derived from "arch/i386/kernel/process.c"
   3  *    Copyright (C) 1995  Linus Torvalds
   4  *
   5  *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
   6  *  Paul Mackerras (paulus@cs.anu.edu.au)
   7  *
   8  *  PowerPC version
   9  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  10  *
  11  *  This program is free software; you can redistribute it and/or
  12  *  modify it under the terms of the GNU General Public License
  13  *  as published by the Free Software Foundation; either version
  14  *  2 of the License, or (at your option) any later version.
  15  */
  16
  17 #include <linux/config.h>
  18 #include <linux/errno.h>
  19 #include <linux/sched.h>
  20 #include <linux/kernel.h>
  21 #include <linux/mm.h>
  22 #include <linux/smp.h>
  23 #include <linux/smp_lock.h>
  24 #include <linux/stddef.h>
  25 #include <linux/unistd.h>
  26 #include <linux/ptrace.h>
  27 #include <linux/slab.h>
  28 #include <linux/user.h>
  29 #include <linux/elf.h>
  30 #include <linux/init.h>
  31 #include <linux/prctl.h>
  32 #include <linux/init_task.h>
  33 #include <linux/module.h>
  34 #include <linux/kallsyms.h>
  35 #include <linux/mqueue.h>
  36 #include <linux/hardirq.h>
  37 #include <linux/utsname.h>
  38
  39 #include <asm/pgtable.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/system.h>
  42 #include <asm/io.h>
  43 #include <asm/processor.h>
  44 #include <asm/mmu.h>
  45 #include <asm/prom.h>
  46 #include <asm/machdep.h>
  47 #include <asm/time.h>
  48 #include <asm/syscalls.h>
  49 #ifdef CONFIG_PPC64
  50 #include <asm/firmware.h>
  51 #endif
  52
  53 extern unsigned long _get_SP(void);
  54
  55 #ifndef CONFIG_SMP
  56 struct task_struct *last_task_used_math = NULL;
  57 struct task_struct *last_task_used_altivec = NULL;
  58 struct task_struct *last_task_used_spe = NULL;
  59 #endif
  60
  61 /*
  62  * Make sure the floating-point register state in the
  63  * the thread_struct is up to date for task tsk.
  64  */
  65 void flush_fp_to_thread(struct task_struct *tsk)
  66 {
  67         if (tsk->thread.regs) {
  68                 /*
  69                  * We need to disable preemption here because if we didn't,
  70                  * another process could get scheduled after the regs->msr
  71                  * test but before we have finished saving the FP registers
  72                  * to the thread_struct.  That process could take over the
  73                  * FPU, and then when we get scheduled again we would store
  74                  * bogus values for the remaining FP registers.
  75                  */
  76                 preempt_disable();
  77                 if (tsk->thread.regs->msr & MSR_FP) {
  78 #ifdef CONFIG_SMP
  79                         /*
  80                          * This should only ever be called for current or
  81                          * for a stopped child process.  Since we save away
  82                          * the FP register state on context switch on SMP,
  83                          * there is something wrong if a stopped child appears
  84                          * to still have its FP state in the CPU registers.
  85                          */
  86                         BUG_ON(tsk != current);
  87 #endif
  88                         giveup_fpu(current);
  89                 }
  90                 preempt_enable();
  91         }
  92 }
  93
  94 void enable_kernel_fp(void)
  95 {
  96         WARN_ON(preemptible());
  97
  98 #ifdef CONFIG_SMP
  99         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 100                 giveup_fpu(current);
 101         else
 102                 giveup_fpu(NULL);       /* just enables FP for kernel */
 103 #else
 104         giveup_fpu(last_task_used_math);
 105 #endif /* CONFIG_SMP */
 106 }
 107 EXPORT_SYMBOL(enable_kernel_fp);
 108
 109 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
 110 {
 111         if (!tsk->thread.regs)
 112                 return 0;
 113         flush_fp_to_thread(current);
 114
 115         memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
 116
 117         return 1;
 118 }
 119
 120 #ifdef CONFIG_ALTIVEC
 121 void enable_kernel_altivec(void)
 122 {
 123         WARN_ON(preemptible());
 124
 125 #ifdef CONFIG_SMP
 126         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 127                 giveup_altivec(current);
 128         else
 129                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 130 #else
 131         giveup_altivec(last_task_used_altivec);
 132 #endif /* CONFIG_SMP */
 133 }
 134 EXPORT_SYMBOL(enable_kernel_altivec);
 135
 136 /*
 137  * Make sure the VMX/Altivec register state in the
 138  * the thread_struct is up to date for task tsk.
 139  */
 140 void flush_altivec_to_thread(struct task_struct *tsk)
 141 {
 142         if (tsk->thread.regs) {
 143                 preempt_disable();
 144                 if (tsk->thread.regs->msr & MSR_VEC) {
 145 #ifdef CONFIG_SMP
 146                         BUG_ON(tsk != current);
 147 #endif
 148                         giveup_altivec(current);
 149                 }
 150                 preempt_enable();
 151         }
 152 }
 153
 154 int dump_task_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
 155 {
 156         flush_altivec_to_thread(current);
 157         memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
 158         return 1;
 159 }
 160 #endif /* CONFIG_ALTIVEC */
 161
 162 #ifdef CONFIG_SPE
 163
 164 void enable_kernel_spe(void)
 165 {
 166         WARN_ON(preemptible());
 167
 168 #ifdef CONFIG_SMP
 169         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 170                 giveup_spe(current);
 171         else
 172                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 173 #else
 174         giveup_spe(last_task_used_spe);
 175 #endif /* __SMP __ */
 176 }
 177 EXPORT_SYMBOL(enable_kernel_spe);
 178
 179 void flush_spe_to_thread(struct task_struct *tsk)
 180 {
 181         if (tsk->thread.regs) {
 182                 preempt_disable();
 183                 if (tsk->thread.regs->msr & MSR_SPE) {
 184 #ifdef CONFIG_SMP
 185                         BUG_ON(tsk != current);
 186 #endif
 187                         giveup_spe(current);
 188                 }
 189                 preempt_enable();
 190         }
 191 }
 192
 193 int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 194 {
 195         flush_spe_to_thread(current);
 196         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
 197         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
 198         return 1;
 199 }
 200 #endif /* CONFIG_SPE */
 201
 202 #ifndef CONFIG_SMP
 203 /*
 204  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 205  * and the current task has some state, discard it.
 206  */
 207 void discard_lazy_cpu_state(void)
 208 {
 209         preempt_disable();
 210         if (last_task_used_math == current)
 211                 last_task_used_math = NULL;
 212 #ifdef CONFIG_ALTIVEC
 213         if (last_task_used_altivec == current)
 214                 last_task_used_altivec = NULL;
 215 #endif /* CONFIG_ALTIVEC */
 216 #ifdef CONFIG_SPE
 217         if (last_task_used_spe == current)
 218                 last_task_used_spe = NULL;
 219 #endif
 220         preempt_enable();
 221 }
 222 #endif /* CONFIG_SMP */
 223
 224 #ifdef CONFIG_PPC_MERGE         /* XXX for now */
 225 int set_dabr(unsigned long dabr)
 226 {
 227         if (ppc_md.set_dabr)
 228                 return ppc_md.set_dabr(dabr);
 229
 230         mtspr(SPRN_DABR, dabr);
 231         return 0;
 232 }
 233 #endif
 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
 332         account_system_vtime(current);
 333         account_process_vtime(current);
 334         calculate_steal_time();
 335
 336         last = _switch(old_thread, new_thread);
 337
 338         local_irq_restore(flags);
 339
 340         return last;
 341 }
 342
 343 static int instructions_to_print = 16;
 344
 345 #ifdef CONFIG_PPC64
 346 #define BAD_PC(pc)      ((REGION_ID(pc) != KERNEL_REGION_ID) && \
 347                          (REGION_ID(pc) != VMALLOC_REGION_ID))
 348 #else
 349 #define BAD_PC(pc)      ((pc) < KERNELBASE)
 350 #endif
 351
 352 static void show_instructions(struct pt_regs *regs)
 353 {
 354         int i;
 355         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 356                         sizeof(int));
 357
 358         printk("Instruction dump:");
 359
 360         for (i = 0; i < instructions_to_print; i++) {
 361                 int instr;
 362
 363                 if (!(i % 8))
 364                         printk("\n");
 365
 366                 /* We use __get_user here *only* to avoid an OOPS on a
 367                  * bad address because the pc *should* only be a
 368                  * kernel address.
 369                  */
 370                 if (BAD_PC(pc) || __get_user(instr, (unsigned int __user *)pc)) {
 371                         printk("XXXXXXXX ");
 372                 } else {
 373                         if (regs->nip == pc)
 374                                 printk("<%08x> ", instr);
 375                         else
 376                                 printk("%08x ", instr);
 377                 }
 378
 379                 pc += sizeof(int);
 380         }
 381
 382         printk("\n");
 383 }
 384
 385 static struct regbit {
 386         unsigned long bit;
 387         const char *name;
 388 } msr_bits[] = {
 389         {MSR_EE,        "EE"},
 390         {MSR_PR,        "PR"},
 391         {MSR_FP,        "FP"},
 392         {MSR_ME,        "ME"},
 393         {MSR_IR,        "IR"},
 394         {MSR_DR,        "DR"},
 395         {0,             NULL}
 396 };
 397
 398 static void printbits(unsigned long val, struct regbit *bits)
 399 {
 400         const char *sep = "";
 401
 402         printk("<");
 403         for (; bits->bit; ++bits)
 404                 if (val & bits->bit) {
 405                         printk("%s%s", sep, bits->name);
 406                         sep = ",";
 407                 }
 408         printk(">");
 409 }
 410
 411 #ifdef CONFIG_PPC64
 412 #define REG             "%016lX"
 413 #define REGS_PER_LINE   4
 414 #define LAST_VOLATILE   13
 415 #else
 416 #define REG             "%08lX"
 417 #define REGS_PER_LINE   8
 418 #define LAST_VOLATILE   12
 419 #endif
 420
 421 void show_regs(struct pt_regs * regs)
 422 {
 423         int i, trap;
 424
 425         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 426                regs->nip, regs->link, regs->ctr);
 427         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 428                regs, regs->trap, print_tainted(), system_utsname.release);
 429         printk("MSR: "REG" ", regs->msr);
 430         printbits(regs->msr, msr_bits);
 431         printk("  CR: %08lX  XER: %08lX\n", regs->ccr, regs->xer);
 432         trap = TRAP(regs);
 433         if (trap == 0x300 || trap == 0x600)
 434                 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
 435         printk("TASK = %p[%d] '%s' THREAD: %p",
 436                current, current->pid, current->comm, task_thread_info(current));
 437
 438 #ifdef CONFIG_SMP
 439         printk(" CPU: %d", smp_processor_id());
 440 #endif /* CONFIG_SMP */
 441
 442         for (i = 0;  i < 32;  i++) {
 443                 if ((i % REGS_PER_LINE) == 0)
 444                         printk("\n" KERN_INFO "GPR%02d: ", i);
 445                 printk(REG " ", regs->gpr[i]);
 446                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 447                         break;
 448         }
 449         printk("\n");
 450 #ifdef CONFIG_KALLSYMS
 451         /*
 452          * Lookup NIP late so we have the best change of getting the
 453          * above info out without failing
 454          */
 455         printk("NIP ["REG"] ", regs->nip);
 456         print_symbol("%s\n", regs->nip);
 457         printk("LR ["REG"] ", regs->link);
 458         print_symbol("%s\n", regs->link);
 459 #endif
 460         show_stack(current, (unsigned long *) regs->gpr[1]);
 461         if (!user_mode(regs))
 462                 show_instructions(regs);
 463 }
 464
 465 void exit_thread(void)
 466 {
 467         discard_lazy_cpu_state();
 468 }
 469
 470 void flush_thread(void)
 471 {
 472 #ifdef CONFIG_PPC64
 473         struct thread_info *t = current_thread_info();
 474
 475         if (t->flags & _TIF_ABI_PENDING)
 476                 t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
 477 #endif
 478
 479         discard_lazy_cpu_state();
 480
 481 #ifdef CONFIG_PPC64     /* for now */
 482         if (current->thread.dabr) {
 483                 current->thread.dabr = 0;
 484                 set_dabr(0);
 485         }
 486 #endif
 487 }
 488
 489 void
 490 release_thread(struct task_struct *t)
 491 {
 492 }
 493
 494 /*
 495  * This gets called before we allocate a new thread and copy
 496  * the current task into it.
 497  */
 498 void prepare_to_copy(struct task_struct *tsk)
 499 {
 500         flush_fp_to_thread(current);
 501         flush_altivec_to_thread(current);
 502         flush_spe_to_thread(current);
 503 }
 504
 505 /*
 506  * Copy a thread..
 507  */
 508 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 509                 unsigned long unused, struct task_struct *p,
 510                 struct pt_regs *regs)
 511 {
 512         struct pt_regs *childregs, *kregs;
 513         extern void ret_from_fork(void);
 514         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 515
 516         CHECK_FULL_REGS(regs);
 517         /* Copy registers */
 518         sp -= sizeof(struct pt_regs);
 519         childregs = (struct pt_regs *) sp;
 520         *childregs = *regs;
 521         if ((childregs->msr & MSR_PR) == 0) {
 522                 /* for kernel thread, set `current' and stackptr in new task */
 523                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 524 #ifdef CONFIG_PPC32
 525                 childregs->gpr[2] = (unsigned long) p;
 526 #else
 527                 clear_tsk_thread_flag(p, TIF_32BIT);
 528 #endif
 529                 p->thread.regs = NULL;  /* no user register state */
 530         } else {
 531                 childregs->gpr[1] = usp;
 532                 p->thread.regs = childregs;
 533                 if (clone_flags & CLONE_SETTLS) {
 534 #ifdef CONFIG_PPC64
 535                         if (!test_thread_flag(TIF_32BIT))
 536                                 childregs->gpr[13] = childregs->gpr[6];
 537                         else
 538 #endif
 539                                 childregs->gpr[2] = childregs->gpr[6];
 540                 }
 541         }
 542         childregs->gpr[3] = 0;  /* Result from fork() */
 543         sp -= STACK_FRAME_OVERHEAD;
 544
 545         /*
 546          * The way this works is that at some point in the future
 547          * some task will call _switch to switch to the new task.
 548          * That will pop off the stack frame created below and start
 549          * the new task running at ret_from_fork.  The new task will
 550          * do some house keeping and then return from the fork or clone
 551          * system call, using the stack frame created above.
 552          */
 553         sp -= sizeof(struct pt_regs);
 554         kregs = (struct pt_regs *) sp;
 555         sp -= STACK_FRAME_OVERHEAD;
 556         p->thread.ksp = sp;
 557
 558 #ifdef CONFIG_PPC64
 559         if (cpu_has_feature(CPU_FTR_SLB)) {
 560                 unsigned long sp_vsid = get_kernel_vsid(sp);
 561                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 562
 563                 sp_vsid <<= SLB_VSID_SHIFT;
 564                 sp_vsid |= SLB_VSID_KERNEL | llp;
 565                 p->thread.ksp_vsid = sp_vsid;
 566         }
 567
 568         /*
 569          * The PPC64 ABI makes use of a TOC to contain function
 570          * pointers.  The function (ret_from_except) is actually a pointer
 571          * to the TOC entry.  The first entry is a pointer to the actual
 572          * function.
 573          */
 574         kregs->nip = *((unsigned long *)ret_from_fork);
 575 #else
 576         kregs->nip = (unsigned long)ret_from_fork;
 577         p->thread.last_syscall = -1;
 578 #endif
 579
 580         return 0;
 581 }
 582
 583 /*
 584  * Set up a thread for executing a new program
 585  */
 586 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 587 {
 588 #ifdef CONFIG_PPC64
 589         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 590 #endif
 591
 592         set_fs(USER_DS);
 593
 594         /*
 595          * If we exec out of a kernel thread then thread.regs will not be
 596          * set.  Do it now.
 597          */
 598         if (!current->thread.regs) {
 599                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
 600                 current->thread.regs = regs - 1;
 601         }
 602
 603         memset(regs->gpr, 0, sizeof(regs->gpr));
 604         regs->ctr = 0;
 605         regs->link = 0;
 606         regs->xer = 0;
 607         regs->ccr = 0;
 608         regs->gpr[1] = sp;
 609
 610 #ifdef CONFIG_PPC32
 611         regs->mq = 0;
 612         regs->nip = start;
 613         regs->msr = MSR_USER;
 614 #else
 615         if (!test_thread_flag(TIF_32BIT)) {
 616                 unsigned long entry, toc;
 617
 618                 /* start is a relocated pointer to the function descriptor for
 619                  * the elf _start routine.  The first entry in the function
 620                  * descriptor is the entry address of _start and the second
 621                  * entry is the TOC value we need to use.
 622                  */
 623                 __get_user(entry, (unsigned long __user *)start);
 624                 __get_user(toc, (unsigned long __user *)start+1);
 625
 626                 /* Check whether the e_entry function descriptor entries
 627                  * need to be relocated before we can use them.
 628                  */
 629                 if (load_addr != 0) {
 630                         entry += load_addr;
 631                         toc   += load_addr;
 632                 }
 633                 regs->nip = entry;
 634                 regs->gpr[2] = toc;
 635                 regs->msr = MSR_USER64;
 636         } else {
 637                 regs->nip = start;
 638                 regs->gpr[2] = 0;
 639                 regs->msr = MSR_USER32;
 640         }
 641 #endif
 642
 643         discard_lazy_cpu_state();
 644         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 645         current->thread.fpscr.val = 0;
 646 #ifdef CONFIG_ALTIVEC
 647         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 648         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 649         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 650         current->thread.vrsave = 0;
 651         current->thread.used_vr = 0;
 652 #endif /* CONFIG_ALTIVEC */
 653 #ifdef CONFIG_SPE
 654         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 655         current->thread.acc = 0;
 656         current->thread.spefscr = 0;
 657         current->thread.used_spe = 0;
 658 #endif /* CONFIG_SPE */
 659 }
 660
 661 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 662                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 663
 664 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 665 {
 666         struct pt_regs *regs = tsk->thread.regs;
 667
 668         /* This is a bit hairy.  If we are an SPE enabled  processor
 669          * (have embedded fp) we store the IEEE exception enable flags in
 670          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 671          * mode (asyn, precise, disabled) for 'Classic' FP. */
 672         if (val & PR_FP_EXC_SW_ENABLE) {
 673 #ifdef CONFIG_SPE
 674                 tsk->thread.fpexc_mode = val &
 675                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 676                 return 0;
 677 #else
 678                 return -EINVAL;
 679 #endif
 680         }
 681
 682         /* on a CONFIG_SPE this does not hurt us.  The bits that
 683          * __pack_fe01 use do not overlap with bits used for
 684          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 685          * on CONFIG_SPE implementations are reserved so writing to
 686          * them does not change anything */
 687         if (val > PR_FP_EXC_PRECISE)
 688                 return -EINVAL;
 689         tsk->thread.fpexc_mode = __pack_fe01(val);
 690         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 691                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 692                         | tsk->thread.fpexc_mode;
 693         return 0;
 694 }
 695
 696 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 697 {
 698         unsigned int val;
 699
 700         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 701 #ifdef CONFIG_SPE
 702                 val = tsk->thread.fpexc_mode;
 703 #else
 704                 return -EINVAL;
 705 #endif
 706         else
 707                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 708         return put_user(val, (unsigned int __user *) adr);
 709 }
 710
 711 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
 712
 713 int sys_clone(unsigned long clone_flags, unsigned long usp,
 714               int __user *parent_tidp, void __user *child_threadptr,
 715               int __user *child_tidp, int p6,
 716               struct pt_regs *regs)
 717 {
 718         CHECK_FULL_REGS(regs);
 719         if (usp == 0)
 720                 usp = regs->gpr[1];     /* stack pointer for child */
 721 #ifdef CONFIG_PPC64
 722         if (test_thread_flag(TIF_32BIT)) {
 723                 parent_tidp = TRUNC_PTR(parent_tidp);
 724                 child_tidp = TRUNC_PTR(child_tidp);
 725         }
 726 #endif
 727         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 728 }
 729
 730 int sys_fork(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(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 736 }
 737
 738 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 739               unsigned long p4, unsigned long p5, unsigned long p6,
 740               struct pt_regs *regs)
 741 {
 742         CHECK_FULL_REGS(regs);
 743         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 744                         regs, 0, NULL, NULL);
 745 }
 746
 747 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 748                unsigned long a3, unsigned long a4, unsigned long a5,
 749                struct pt_regs *regs)
 750 {
 751         int error;
 752         char *filename;
 753
 754         filename = getname((char __user *) a0);
 755         error = PTR_ERR(filename);
 756         if (IS_ERR(filename))
 757                 goto out;
 758         flush_fp_to_thread(current);
 759         flush_altivec_to_thread(current);
 760         flush_spe_to_thread(current);
 761         error = do_execve(filename, (char __user * __user *) a1,
 762                           (char __user * __user *) a2, regs);
 763         if (error == 0) {
 764                 task_lock(current);
 765                 current->ptrace &= ~PT_DTRACE;
 766                 task_unlock(current);
 767         }
 768         putname(filename);
 769 out:
 770         return error;
 771 }
 772
 773 int validate_sp(unsigned long sp, struct task_struct *p,
 774                        unsigned long nbytes)
 775 {
 776         unsigned long stack_page = (unsigned long)task_stack_page(p);
 777
 778         if (sp >= stack_page + sizeof(struct thread_struct)
 779             && sp <= stack_page + THREAD_SIZE - nbytes)
 780                 return 1;
 781
 782 #ifdef CONFIG_IRQSTACKS
 783         stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
 784         if (sp >= stack_page + sizeof(struct thread_struct)
 785             && sp <= stack_page + THREAD_SIZE - nbytes)
 786                 return 1;
 787
 788         stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
 789         if (sp >= stack_page + sizeof(struct thread_struct)
 790             && sp <= stack_page + THREAD_SIZE - nbytes)
 791                 return 1;
 792 #endif
 793
 794         return 0;
 795 }
 796
 797 #ifdef CONFIG_PPC64
 798 #define MIN_STACK_FRAME 112     /* same as STACK_FRAME_OVERHEAD, in fact */
 799 #define FRAME_LR_SAVE   2
 800 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
 801 #define REGS_MARKER     0x7265677368657265ul
 802 #define FRAME_MARKER    12
 803 #else
 804 #define MIN_STACK_FRAME 16
 805 #define FRAME_LR_SAVE   1
 806 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
 807 #define REGS_MARKER     0x72656773ul
 808 #define FRAME_MARKER    2
 809 #endif
 810
 811 EXPORT_SYMBOL(validate_sp);
 812
 813 unsigned long get_wchan(struct task_struct *p)
 814 {
 815         unsigned long ip, sp;
 816         int count = 0;
 817
 818         if (!p || p == current || p->state == TASK_RUNNING)
 819                 return 0;
 820
 821         sp = p->thread.ksp;
 822         if (!validate_sp(sp, p, MIN_STACK_FRAME))
 823                 return 0;
 824
 825         do {
 826                 sp = *(unsigned long *)sp;
 827                 if (!validate_sp(sp, p, MIN_STACK_FRAME))
 828                         return 0;
 829                 if (count > 0) {
 830                         ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
 831                         if (!in_sched_functions(ip))
 832                                 return ip;
 833                 }
 834         } while (count++ < 16);
 835         return 0;
 836 }
 837
 838 static int kstack_depth_to_print = 64;
 839
 840 void show_stack(struct task_struct *tsk, unsigned long *stack)
 841 {
 842         unsigned long sp, ip, lr, newsp;
 843         int count = 0;
 844         int firstframe = 1;
 845
 846         sp = (unsigned long) stack;
 847         if (tsk == NULL)
 848                 tsk = current;
 849         if (sp == 0) {
 850                 if (tsk == current)
 851                         asm("mr %0,1" : "=r" (sp));
 852                 else
 853                         sp = tsk->thread.ksp;
 854         }
 855
 856         lr = 0;
 857         printk("Call Trace:\n");
 858         do {
 859                 if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
 860                         return;
 861
 862                 stack = (unsigned long *) sp;
 863                 newsp = stack[0];
 864                 ip = stack[FRAME_LR_SAVE];
 865                 if (!firstframe || ip != lr) {
 866                         printk("["REG"] ["REG"] ", sp, ip);
 867                         print_symbol("%s", ip);
 868                         if (firstframe)
 869                                 printk(" (unreliable)");
 870                         printk("\n");
 871                 }
 872                 firstframe = 0;
 873
 874                 /*
 875                  * See if this is an exception frame.
 876                  * We look for the "regshere" marker in the current frame.
 877                  */
 878                 if (validate_sp(sp, tsk, INT_FRAME_SIZE)
 879                     && stack[FRAME_MARKER] == REGS_MARKER) {
 880                         struct pt_regs *regs = (struct pt_regs *)
 881                                 (sp + STACK_FRAME_OVERHEAD);
 882                         printk("--- Exception: %lx", regs->trap);
 883                         print_symbol(" at %s\n", regs->nip);
 884                         lr = regs->link;
 885                         print_symbol("    LR = %s\n", lr);
 886                         firstframe = 1;
 887                 }
 888
 889                 sp = newsp;
 890         } while (count++ < kstack_depth_to_print);
 891 }
 892
 893 void dump_stack(void)
 894 {
 895         show_stack(current, NULL);
 896 }
 897 EXPORT_SYMBOL(dump_stack);
 898
 899 #ifdef CONFIG_PPC64
 900 void ppc64_runlatch_on(void)
 901 {
 902         unsigned long ctrl;
 903
 904         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
 905                 HMT_medium();
 906
 907                 ctrl = mfspr(SPRN_CTRLF);
 908                 ctrl |= CTRL_RUNLATCH;
 909                 mtspr(SPRN_CTRLT, ctrl);
 910
 911                 set_thread_flag(TIF_RUNLATCH);
 912         }
 913 }
 914
 915 void ppc64_runlatch_off(void)
 916 {
 917         unsigned long ctrl;
 918
 919         if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) {
 920                 HMT_medium();
 921
 922                 clear_thread_flag(TIF_RUNLATCH);
 923
 924                 ctrl = mfspr(SPRN_CTRLF);
 925                 ctrl &= ~CTRL_RUNLATCH;
 926                 mtspr(SPRN_CTRLT, ctrl);
 927         }
 928 }
 929 #endif