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   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
 461 #ifndef CONFIG_SMP
 462         if (last_task_used_math == current)
 463                 last_task_used_math = NULL;
 464 #ifdef CONFIG_ALTIVEC
 465         if (last_task_used_altivec == current)
 466                 last_task_used_altivec = NULL;
 467 #endif /* CONFIG_ALTIVEC */
 468 #ifdef CONFIG_SPE
 469         if (last_task_used_spe == current)
 470                 last_task_used_spe = NULL;
 471 #endif
 472 #endif /* CONFIG_SMP */
 473
 474 #ifdef CONFIG_PPC64     /* for now */
 475         if (current->thread.dabr) {
 476                 current->thread.dabr = 0;
 477                 set_dabr(0);
 478         }
 479 #endif
 480 }
 481
 482 void
 483 release_thread(struct task_struct *t)
 484 {
 485 }
 486
 487 /*
 488  * This gets called before we allocate a new thread and copy
 489  * the current task into it.
 490  */
 491 void prepare_to_copy(struct task_struct *tsk)
 492 {
 493         flush_fp_to_thread(current);
 494         flush_altivec_to_thread(current);
 495         flush_spe_to_thread(current);
 496 }
 497
 498 /*
 499  * Copy a thread..
 500  */
 501 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 502                 unsigned long unused, struct task_struct *p,
 503                 struct pt_regs *regs)
 504 {
 505         struct pt_regs *childregs, *kregs;
 506         extern void ret_from_fork(void);
 507         unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
 508
 509         CHECK_FULL_REGS(regs);
 510         /* Copy registers */
 511         sp -= sizeof(struct pt_regs);
 512         childregs = (struct pt_regs *) sp;
 513         *childregs = *regs;
 514         if ((childregs->msr & MSR_PR) == 0) {
 515                 /* for kernel thread, set `current' and stackptr in new task */
 516                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 517 #ifdef CONFIG_PPC32
 518                 childregs->gpr[2] = (unsigned long) p;
 519 #else
 520                 clear_ti_thread_flag(p->thread_info, TIF_32BIT);
 521 #endif
 522                 p->thread.regs = NULL;  /* no user register state */
 523         } else {
 524                 childregs->gpr[1] = usp;
 525                 p->thread.regs = childregs;
 526                 if (clone_flags & CLONE_SETTLS) {
 527 #ifdef CONFIG_PPC64
 528                         if (!test_thread_flag(TIF_32BIT))
 529                                 childregs->gpr[13] = childregs->gpr[6];
 530                         else
 531 #endif
 532                                 childregs->gpr[2] = childregs->gpr[6];
 533                 }
 534         }
 535         childregs->gpr[3] = 0;  /* Result from fork() */
 536         sp -= STACK_FRAME_OVERHEAD;
 537
 538         /*
 539          * The way this works is that at some point in the future
 540          * some task will call _switch to switch to the new task.
 541          * That will pop off the stack frame created below and start
 542          * the new task running at ret_from_fork.  The new task will
 543          * do some house keeping and then return from the fork or clone
 544          * system call, using the stack frame created above.
 545          */
 546         sp -= sizeof(struct pt_regs);
 547         kregs = (struct pt_regs *) sp;
 548         sp -= STACK_FRAME_OVERHEAD;
 549         p->thread.ksp = sp;
 550
 551 #ifdef CONFIG_PPC64
 552         if (cpu_has_feature(CPU_FTR_SLB)) {
 553                 unsigned long sp_vsid = get_kernel_vsid(sp);
 554                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 555
 556                 sp_vsid <<= SLB_VSID_SHIFT;
 557                 sp_vsid |= SLB_VSID_KERNEL | llp;
 558                 p->thread.ksp_vsid = sp_vsid;
 559         }
 560
 561         /*
 562          * The PPC64 ABI makes use of a TOC to contain function
 563          * pointers.  The function (ret_from_except) is actually a pointer
 564          * to the TOC entry.  The first entry is a pointer to the actual
 565          * function.
 566          */
 567         kregs->nip = *((unsigned long *)ret_from_fork);
 568 #else
 569         kregs->nip = (unsigned long)ret_from_fork;
 570         p->thread.last_syscall = -1;
 571 #endif
 572
 573         return 0;
 574 }
 575
 576 /*
 577  * Set up a thread for executing a new program
 578  */
 579 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 580 {
 581 #ifdef CONFIG_PPC64
 582         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 583 #endif
 584
 585         set_fs(USER_DS);
 586
 587         /*
 588          * If we exec out of a kernel thread then thread.regs will not be
 589          * set.  Do it now.
 590          */
 591         if (!current->thread.regs) {
 592                 unsigned long childregs = (unsigned long)current->thread_info +
 593                                                 THREAD_SIZE;
 594                 childregs -= sizeof(struct pt_regs);
 595                 current->thread.regs = (struct pt_regs *)childregs;
 596         }
 597
 598         memset(regs->gpr, 0, sizeof(regs->gpr));
 599         regs->ctr = 0;
 600         regs->link = 0;
 601         regs->xer = 0;
 602         regs->ccr = 0;
 603         regs->gpr[1] = sp;
 604
 605 #ifdef CONFIG_PPC32
 606         regs->mq = 0;
 607         regs->nip = start;
 608         regs->msr = MSR_USER;
 609 #else
 610         if (!test_thread_flag(TIF_32BIT)) {
 611                 unsigned long entry, toc;
 612
 613                 /* start is a relocated pointer to the function descriptor for
 614                  * the elf _start routine.  The first entry in the function
 615                  * descriptor is the entry address of _start and the second
 616                  * entry is the TOC value we need to use.
 617                  */
 618                 __get_user(entry, (unsigned long __user *)start);
 619                 __get_user(toc, (unsigned long __user *)start+1);
 620
 621                 /* Check whether the e_entry function descriptor entries
 622                  * need to be relocated before we can use them.
 623                  */
 624                 if (load_addr != 0) {
 625                         entry += load_addr;
 626                         toc   += load_addr;
 627                 }
 628                 regs->nip = entry;
 629                 regs->gpr[2] = toc;
 630                 regs->msr = MSR_USER64;
 631         } else {
 632                 regs->nip = start;
 633                 regs->gpr[2] = 0;
 634                 regs->msr = MSR_USER32;
 635         }
 636 #endif
 637
 638 #ifndef CONFIG_SMP
 639         if (last_task_used_math == current)
 640                 last_task_used_math = NULL;
 641 #ifdef CONFIG_ALTIVEC
 642         if (last_task_used_altivec == current)
 643                 last_task_used_altivec = NULL;
 644 #endif
 645 #ifdef CONFIG_SPE
 646         if (last_task_used_spe == current)
 647                 last_task_used_spe = NULL;
 648 #endif
 649 #endif /* CONFIG_SMP */
 650         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 651         current->thread.fpscr.val = 0;
 652 #ifdef CONFIG_ALTIVEC
 653         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 654         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 655         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 656         current->thread.vrsave = 0;
 657         current->thread.used_vr = 0;
 658 #endif /* CONFIG_ALTIVEC */
 659 #ifdef CONFIG_SPE
 660         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 661         current->thread.acc = 0;
 662         current->thread.spefscr = 0;
 663         current->thread.used_spe = 0;
 664 #endif /* CONFIG_SPE */
 665 }
 666
 667 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 668                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 669
 670 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 671 {
 672         struct pt_regs *regs = tsk->thread.regs;
 673
 674         /* This is a bit hairy.  If we are an SPE enabled  processor
 675          * (have embedded fp) we store the IEEE exception enable flags in
 676          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 677          * mode (asyn, precise, disabled) for 'Classic' FP. */
 678         if (val & PR_FP_EXC_SW_ENABLE) {
 679 #ifdef CONFIG_SPE
 680                 tsk->thread.fpexc_mode = val &
 681                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 682                 return 0;
 683 #else
 684                 return -EINVAL;
 685 #endif
 686         }
 687
 688         /* on a CONFIG_SPE this does not hurt us.  The bits that
 689          * __pack_fe01 use do not overlap with bits used for
 690          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 691          * on CONFIG_SPE implementations are reserved so writing to
 692          * them does not change anything */
 693         if (val > PR_FP_EXC_PRECISE)
 694                 return -EINVAL;
 695         tsk->thread.fpexc_mode = __pack_fe01(val);
 696         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 697                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 698                         | tsk->thread.fpexc_mode;
 699         return 0;
 700 }
 701
 702 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 703 {
 704         unsigned int val;
 705
 706         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 707 #ifdef CONFIG_SPE
 708                 val = tsk->thread.fpexc_mode;
 709 #else
 710                 return -EINVAL;
 711 #endif
 712         else
 713                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 714         return put_user(val, (unsigned int __user *) adr);
 715 }
 716
 717 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
 718
 719 int sys_clone(unsigned long clone_flags, unsigned long usp,
 720               int __user *parent_tidp, void __user *child_threadptr,
 721               int __user *child_tidp, int p6,
 722               struct pt_regs *regs)
 723 {
 724         CHECK_FULL_REGS(regs);
 725         if (usp == 0)
 726                 usp = regs->gpr[1];     /* stack pointer for child */
 727 #ifdef CONFIG_PPC64
 728         if (test_thread_flag(TIF_32BIT)) {
 729                 parent_tidp = TRUNC_PTR(parent_tidp);
 730                 child_tidp = TRUNC_PTR(child_tidp);
 731         }
 732 #endif
 733         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 734 }
 735
 736 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 737              unsigned long p4, unsigned long p5, unsigned long p6,
 738              struct pt_regs *regs)
 739 {
 740         CHECK_FULL_REGS(regs);
 741         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 742 }
 743
 744 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 745               unsigned long p4, unsigned long p5, unsigned long p6,
 746               struct pt_regs *regs)
 747 {
 748         CHECK_FULL_REGS(regs);
 749         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 750                         regs, 0, NULL, NULL);
 751 }
 752
 753 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 754                unsigned long a3, unsigned long a4, unsigned long a5,
 755                struct pt_regs *regs)
 756 {
 757         int error;
 758         char *filename;
 759
 760         filename = getname((char __user *) a0);
 761         error = PTR_ERR(filename);
 762         if (IS_ERR(filename))
 763                 goto out;
 764         flush_fp_to_thread(current);
 765         flush_altivec_to_thread(current);
 766         flush_spe_to_thread(current);
 767         error = do_execve(filename, (char __user * __user *) a1,
 768                           (char __user * __user *) a2, regs);
 769         if (error == 0) {
 770                 task_lock(current);
 771                 current->ptrace &= ~PT_DTRACE;
 772                 task_unlock(current);
 773         }
 774         putname(filename);
 775 out:
 776         return error;
 777 }
 778
 779 static int validate_sp(unsigned long sp, struct task_struct *p,
 780                        unsigned long nbytes)
 781 {
 782         unsigned long stack_page = (unsigned long)p->thread_info;
 783
 784         if (sp >= stack_page + sizeof(struct thread_struct)
 785             && sp <= stack_page + THREAD_SIZE - nbytes)
 786                 return 1;
 787
 788 #ifdef CONFIG_IRQSTACKS
 789         stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
 790         if (sp >= stack_page + sizeof(struct thread_struct)
 791             && sp <= stack_page + THREAD_SIZE - nbytes)
 792                 return 1;
 793
 794         stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
 795         if (sp >= stack_page + sizeof(struct thread_struct)
 796             && sp <= stack_page + THREAD_SIZE - nbytes)
 797                 return 1;
 798 #endif
 799
 800         return 0;
 801 }
 802
 803 #ifdef CONFIG_PPC64
 804 #define MIN_STACK_FRAME 112     /* same as STACK_FRAME_OVERHEAD, in fact */
 805 #define FRAME_LR_SAVE   2
 806 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
 807 #define REGS_MARKER     0x7265677368657265ul
 808 #define FRAME_MARKER    12
 809 #else
 810 #define MIN_STACK_FRAME 16
 811 #define FRAME_LR_SAVE   1
 812 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
 813 #define REGS_MARKER     0x72656773ul
 814 #define FRAME_MARKER    2
 815 #endif
 816
 817 unsigned long get_wchan(struct task_struct *p)
 818 {
 819         unsigned long ip, sp;
 820         int count = 0;
 821
 822         if (!p || p == current || p->state == TASK_RUNNING)
 823                 return 0;
 824
 825         sp = p->thread.ksp;
 826         if (!validate_sp(sp, p, MIN_STACK_FRAME))
 827                 return 0;
 828
 829         do {
 830                 sp = *(unsigned long *)sp;
 831                 if (!validate_sp(sp, p, MIN_STACK_FRAME))
 832                         return 0;
 833                 if (count > 0) {
 834                         ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
 835                         if (!in_sched_functions(ip))
 836                                 return ip;
 837                 }
 838         } while (count++ < 16);
 839         return 0;
 840 }
 841 EXPORT_SYMBOL(get_wchan);
 842
 843 static int kstack_depth_to_print = 64;
 844
 845 void show_stack(struct task_struct *tsk, unsigned long *stack)
 846 {
 847         unsigned long sp, ip, lr, newsp;
 848         int count = 0;
 849         int firstframe = 1;
 850
 851         sp = (unsigned long) stack;
 852         if (tsk == NULL)
 853                 tsk = current;
 854         if (sp == 0) {
 855                 if (tsk == current)
 856                         asm("mr %0,1" : "=r" (sp));
 857                 else
 858                         sp = tsk->thread.ksp;
 859         }
 860
 861         lr = 0;
 862         printk("Call Trace:\n");
 863         do {
 864                 if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
 865                         return;
 866
 867                 stack = (unsigned long *) sp;
 868                 newsp = stack[0];
 869                 ip = stack[FRAME_LR_SAVE];
 870                 if (!firstframe || ip != lr) {
 871                         printk("["REG"] ["REG"] ", sp, ip);
 872                         print_symbol("%s", ip);
 873                         if (firstframe)
 874                                 printk(" (unreliable)");
 875                         printk("\n");
 876                 }
 877                 firstframe = 0;
 878
 879                 /*
 880                  * See if this is an exception frame.
 881                  * We look for the "regshere" marker in the current frame.
 882                  */
 883                 if (validate_sp(sp, tsk, INT_FRAME_SIZE)
 884                     && stack[FRAME_MARKER] == REGS_MARKER) {
 885                         struct pt_regs *regs = (struct pt_regs *)
 886                                 (sp + STACK_FRAME_OVERHEAD);
 887                         printk("--- Exception: %lx", regs->trap);
 888                         print_symbol(" at %s\n", regs->nip);
 889                         lr = regs->link;
 890                         print_symbol("    LR = %s\n", lr);
 891                         firstframe = 1;
 892                 }
 893
 894                 sp = newsp;
 895         } while (count++ < kstack_depth_to_print);
 896 }
 897
 898 void dump_stack(void)
 899 {
 900         show_stack(current, NULL);
 901 }
 902 EXPORT_SYMBOL(dump_stack);