arch/powerpc/kernel/process.c

   1 /*
   2  *  arch/ppc/kernel/process.c
   3  *
   4  *  Derived from "arch/i386/kernel/process.c"
   5  *    Copyright (C) 1995  Linus Torvalds
   6  *
   7  *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
   8  *  Paul Mackerras (paulus@cs.anu.edu.au)
   9  *
  10  *  PowerPC version
  11  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  12  *
  13  *  This program is free software; you can redistribute it and/or
  14  *  modify it under the terms of the GNU General Public License
  15  *  as published by the Free Software Foundation; either version
  16  *  2 of the License, or (at your option) any later version.
  17  */
  18
  19 #include <linux/config.h>
  20 #include <linux/errno.h>
  21 #include <linux/sched.h>
  22 #include <linux/kernel.h>
  23 #include <linux/mm.h>
  24 #include <linux/smp.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/stddef.h>
  27 #include <linux/unistd.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/slab.h>
  30 #include <linux/user.h>
  31 #include <linux/elf.h>
  32 #include <linux/init.h>
  33 #include <linux/prctl.h>
  34 #include <linux/init_task.h>
  35 #include <linux/module.h>
  36 #include <linux/kallsyms.h>
  37 #include <linux/mqueue.h>
  38 #include <linux/hardirq.h>
  39 #include <linux/utsname.h>
  40 #include <linux/kprobes.h>
  41
  42 #include <asm/pgtable.h>
  43 #include <asm/uaccess.h>
  44 #include <asm/system.h>
  45 #include <asm/io.h>
  46 #include <asm/processor.h>
  47 #include <asm/mmu.h>
  48 #include <asm/prom.h>
  49 #ifdef CONFIG_PPC64
  50 #include <asm/firmware.h>
  51 #include <asm/time.h>
  52 #include <asm/machdep.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 #ifdef CONFIG_PPC64
 207         if (ppc_md.set_dabr)
 208                 return ppc_md.set_dabr(dabr);
 209 #endif
 210
 211         mtspr(SPRN_DABR, dabr);
 212         return 0;
 213 }
 214
 215 #ifdef CONFIG_PPC64
 216 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 217 static DEFINE_PER_CPU(unsigned long, current_dabr);
 218 #endif
 219
 220 struct task_struct *__switch_to(struct task_struct *prev,
 221         struct task_struct *new)
 222 {
 223         struct thread_struct *new_thread, *old_thread;
 224         unsigned long flags;
 225         struct task_struct *last;
 226
 227 #ifdef CONFIG_SMP
 228         /* avoid complexity of lazy save/restore of fpu
 229          * by just saving it every time we switch out if
 230          * this task used the fpu during the last quantum.
 231          *
 232          * If it tries to use the fpu again, it'll trap and
 233          * reload its fp regs.  So we don't have to do a restore
 234          * every switch, just a save.
 235          *  -- Cort
 236          */
 237         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 238                 giveup_fpu(prev);
 239 #ifdef CONFIG_ALTIVEC
 240         /*
 241          * If the previous thread used altivec in the last quantum
 242          * (thus changing altivec regs) then save them.
 243          * We used to check the VRSAVE register but not all apps
 244          * set it, so we don't rely on it now (and in fact we need
 245          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 246          *
 247          * On SMP we always save/restore altivec regs just to avoid the
 248          * complexity of changing processors.
 249          *  -- Cort
 250          */
 251         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 252                 giveup_altivec(prev);
 253 #endif /* CONFIG_ALTIVEC */
 254 #ifdef CONFIG_SPE
 255         /*
 256          * If the previous thread used spe in the last quantum
 257          * (thus changing spe regs) then save them.
 258          *
 259          * On SMP we always save/restore spe regs just to avoid the
 260          * complexity of changing processors.
 261          */
 262         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 263                 giveup_spe(prev);
 264 #endif /* CONFIG_SPE */
 265
 266 #else  /* CONFIG_SMP */
 267 #ifdef CONFIG_ALTIVEC
 268         /* Avoid the trap.  On smp this this never happens since
 269          * we don't set last_task_used_altivec -- Cort
 270          */
 271         if (new->thread.regs && last_task_used_altivec == new)
 272                 new->thread.regs->msr |= MSR_VEC;
 273 #endif /* CONFIG_ALTIVEC */
 274 #ifdef CONFIG_SPE
 275         /* Avoid the trap.  On smp this this never happens since
 276          * we don't set last_task_used_spe
 277          */
 278         if (new->thread.regs && last_task_used_spe == new)
 279                 new->thread.regs->msr |= MSR_SPE;
 280 #endif /* CONFIG_SPE */
 281
 282 #endif /* CONFIG_SMP */
 283
 284 #ifdef CONFIG_PPC64     /* for now */
 285         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
 286                 set_dabr(new->thread.dabr);
 287                 __get_cpu_var(current_dabr) = new->thread.dabr;
 288         }
 289
 290         flush_tlb_pending();
 291 #endif
 292
 293         new_thread = &new->thread;
 294         old_thread = &current->thread;
 295
 296 #ifdef CONFIG_PPC64
 297         /*
 298          * Collect processor utilization data per process
 299          */
 300         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 301                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 302                 long unsigned start_tb, current_tb;
 303                 start_tb = old_thread->start_tb;
 304                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 305                 old_thread->accum_tb += (current_tb - start_tb);
 306                 new_thread->start_tb = current_tb;
 307         }
 308 #endif
 309
 310         local_irq_save(flags);
 311         last = _switch(old_thread, new_thread);
 312
 313         local_irq_restore(flags);
 314
 315         return last;
 316 }
 317
 318 static int instructions_to_print = 16;
 319
 320 #ifdef CONFIG_PPC64
 321 #define BAD_PC(pc)      ((REGION_ID(pc) != KERNEL_REGION_ID) && \
 322                          (REGION_ID(pc) != VMALLOC_REGION_ID))
 323 #else
 324 #define BAD_PC(pc)      ((pc) < KERNELBASE)
 325 #endif
 326
 327 static void show_instructions(struct pt_regs *regs)
 328 {
 329         int i;
 330         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 331                         sizeof(int));
 332
 333         printk("Instruction dump:");
 334
 335         for (i = 0; i < instructions_to_print; i++) {
 336                 int instr;
 337
 338                 if (!(i % 8))
 339                         printk("\n");
 340
 341                 if (BAD_PC(pc) || __get_user(instr, (unsigned int *)pc)) {
 342                         printk("XXXXXXXX ");
 343                 } else {
 344                         if (regs->nip == pc)
 345                                 printk("<%08x> ", instr);
 346                         else
 347                                 printk("%08x ", instr);
 348                 }
 349
 350                 pc += sizeof(int);
 351         }
 352
 353         printk("\n");
 354 }
 355
 356 static struct regbit {
 357         unsigned long bit;
 358         const char *name;
 359 } msr_bits[] = {
 360         {MSR_EE,        "EE"},
 361         {MSR_PR,        "PR"},
 362         {MSR_FP,        "FP"},
 363         {MSR_ME,        "ME"},
 364         {MSR_IR,        "IR"},
 365         {MSR_DR,        "DR"},
 366         {0,             NULL}
 367 };
 368
 369 static void printbits(unsigned long val, struct regbit *bits)
 370 {
 371         const char *sep = "";
 372
 373         printk("<");
 374         for (; bits->bit; ++bits)
 375                 if (val & bits->bit) {
 376                         printk("%s%s", sep, bits->name);
 377                         sep = ",";
 378                 }
 379         printk(">");
 380 }
 381
 382 #ifdef CONFIG_PPC64
 383 #define REG             "%016lX"
 384 #define REGS_PER_LINE   4
 385 #define LAST_VOLATILE   13
 386 #else
 387 #define REG             "%08lX"
 388 #define REGS_PER_LINE   8
 389 #define LAST_VOLATILE   12
 390 #endif
 391
 392 void show_regs(struct pt_regs * regs)
 393 {
 394         int i, trap;
 395
 396         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 397                regs->nip, regs->link, regs->ctr);
 398         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 399                regs, regs->trap, print_tainted(), system_utsname.release);
 400         printk("MSR: "REG" ", regs->msr);
 401         printbits(regs->msr, msr_bits);
 402         printk("  CR: %08lX  XER: %08lX\n", regs->ccr, regs->xer);
 403         trap = TRAP(regs);
 404         if (trap == 0x300 || trap == 0x600)
 405                 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
 406         printk("TASK = %p[%d] '%s' THREAD: %p",
 407                current, current->pid, current->comm, current->thread_info);
 408
 409 #ifdef CONFIG_SMP
 410         printk(" CPU: %d", smp_processor_id());
 411 #endif /* CONFIG_SMP */
 412
 413         for (i = 0;  i < 32;  i++) {
 414                 if ((i % REGS_PER_LINE) == 0)
 415                         printk("\n" KERN_INFO "GPR%02d: ", i);
 416                 printk(REG " ", regs->gpr[i]);
 417                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 418                         break;
 419         }
 420         printk("\n");
 421 #ifdef CONFIG_KALLSYMS
 422         /*
 423          * Lookup NIP late so we have the best change of getting the
 424          * above info out without failing
 425          */
 426         printk("NIP ["REG"] ", regs->nip);
 427         print_symbol("%s\n", regs->nip);
 428         printk("LR ["REG"] ", regs->link);
 429         print_symbol("%s\n", regs->link);
 430 #endif
 431         show_stack(current, (unsigned long *) regs->gpr[1]);
 432         if (!user_mode(regs))
 433                 show_instructions(regs);
 434 }
 435
 436 void exit_thread(void)
 437 {
 438         kprobe_flush_task(current);
 439
 440 #ifndef CONFIG_SMP
 441         if (last_task_used_math == current)
 442                 last_task_used_math = NULL;
 443 #ifdef CONFIG_ALTIVEC
 444         if (last_task_used_altivec == current)
 445                 last_task_used_altivec = NULL;
 446 #endif /* CONFIG_ALTIVEC */
 447 #ifdef CONFIG_SPE
 448         if (last_task_used_spe == current)
 449                 last_task_used_spe = NULL;
 450 #endif
 451 #endif /* CONFIG_SMP */
 452 }
 453
 454 void flush_thread(void)
 455 {
 456 #ifdef CONFIG_PPC64
 457         struct thread_info *t = current_thread_info();
 458
 459         if (t->flags & _TIF_ABI_PENDING)
 460                 t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
 461 #endif
 462         kprobe_flush_task(current);
 463
 464 #ifndef CONFIG_SMP
 465         if (last_task_used_math == current)
 466                 last_task_used_math = NULL;
 467 #ifdef CONFIG_ALTIVEC
 468         if (last_task_used_altivec == current)
 469                 last_task_used_altivec = NULL;
 470 #endif /* CONFIG_ALTIVEC */
 471 #ifdef CONFIG_SPE
 472         if (last_task_used_spe == current)
 473                 last_task_used_spe = NULL;
 474 #endif
 475 #endif /* CONFIG_SMP */
 476
 477 #ifdef CONFIG_PPC64     /* for now */
 478         if (current->thread.dabr) {
 479                 current->thread.dabr = 0;
 480                 set_dabr(0);
 481         }
 482 #endif
 483 }
 484
 485 void
 486 release_thread(struct task_struct *t)
 487 {
 488 }
 489
 490 /*
 491  * This gets called before we allocate a new thread and copy
 492  * the current task into it.
 493  */
 494 void prepare_to_copy(struct task_struct *tsk)
 495 {
 496         flush_fp_to_thread(current);
 497         flush_altivec_to_thread(current);
 498         flush_spe_to_thread(current);
 499 }
 500
 501 /*
 502  * Copy a thread..
 503  */
 504 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 505                 unsigned long unused, struct task_struct *p,
 506                 struct pt_regs *regs)
 507 {
 508         struct pt_regs *childregs, *kregs;
 509         extern void ret_from_fork(void);
 510         unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
 511
 512         CHECK_FULL_REGS(regs);
 513         /* Copy registers */
 514         sp -= sizeof(struct pt_regs);
 515         childregs = (struct pt_regs *) sp;
 516         *childregs = *regs;
 517         if ((childregs->msr & MSR_PR) == 0) {
 518                 /* for kernel thread, set `current' and stackptr in new task */
 519                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 520 #ifdef CONFIG_PPC32
 521                 childregs->gpr[2] = (unsigned long) p;
 522 #else
 523                 clear_ti_thread_flag(p->thread_info, TIF_32BIT);
 524 #endif
 525                 p->thread.regs = NULL;  /* no user register state */
 526         } else {
 527                 childregs->gpr[1] = usp;
 528                 p->thread.regs = childregs;
 529                 if (clone_flags & CLONE_SETTLS) {
 530 #ifdef CONFIG_PPC64
 531                         if (!test_thread_flag(TIF_32BIT))
 532                                 childregs->gpr[13] = childregs->gpr[6];
 533                         else
 534 #endif
 535                                 childregs->gpr[2] = childregs->gpr[6];
 536                 }
 537         }
 538         childregs->gpr[3] = 0;  /* Result from fork() */
 539         sp -= STACK_FRAME_OVERHEAD;
 540
 541         /*
 542          * The way this works is that at some point in the future
 543          * some task will call _switch to switch to the new task.
 544          * That will pop off the stack frame created below and start
 545          * the new task running at ret_from_fork.  The new task will
 546          * do some house keeping and then return from the fork or clone
 547          * system call, using the stack frame created above.
 548          */
 549         sp -= sizeof(struct pt_regs);
 550         kregs = (struct pt_regs *) sp;
 551         sp -= STACK_FRAME_OVERHEAD;
 552         p->thread.ksp = sp;
 553
 554 #ifdef CONFIG_PPC64
 555         if (cpu_has_feature(CPU_FTR_SLB)) {
 556                 unsigned long sp_vsid = get_kernel_vsid(sp);
 557                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 558
 559                 sp_vsid <<= SLB_VSID_SHIFT;
 560                 sp_vsid |= SLB_VSID_KERNEL | llp;
 561                 p->thread.ksp_vsid = sp_vsid;
 562         }
 563
 564         /*
 565          * The PPC64 ABI makes use of a TOC to contain function
 566          * pointers.  The function (ret_from_except) is actually a pointer
 567          * to the TOC entry.  The first entry is a pointer to the actual
 568          * function.
 569          */
 570         kregs->nip = *((unsigned long *)ret_from_fork);
 571 #else
 572         kregs->nip = (unsigned long)ret_from_fork;
 573         p->thread.last_syscall = -1;
 574 #endif
 575
 576         return 0;
 577 }
 578
 579 /*
 580  * Set up a thread for executing a new program
 581  */
 582 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 583 {
 584 #ifdef CONFIG_PPC64
 585         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 586 #endif
 587
 588         set_fs(USER_DS);
 589
 590         /*
 591          * If we exec out of a kernel thread then thread.regs will not be
 592          * set.  Do it now.
 593          */
 594         if (!current->thread.regs) {
 595                 unsigned long childregs = (unsigned long)current->thread_info +
 596                                                 THREAD_SIZE;
 597                 childregs -= sizeof(struct pt_regs);
 598                 current->thread.regs = (struct pt_regs *)childregs;
 599         }
 600
 601         memset(regs->gpr, 0, sizeof(regs->gpr));
 602         regs->ctr = 0;
 603         regs->link = 0;
 604         regs->xer = 0;
 605         regs->ccr = 0;
 606         regs->gpr[1] = sp;
 607
 608 #ifdef CONFIG_PPC32
 609         regs->mq = 0;
 610         regs->nip = start;
 611         regs->msr = MSR_USER;
 612 #else
 613         if (!test_thread_flag(TIF_32BIT)) {
 614                 unsigned long entry, toc;
 615
 616                 /* start is a relocated pointer to the function descriptor for
 617                  * the elf _start routine.  The first entry in the function
 618                  * descriptor is the entry address of _start and the second
 619                  * entry is the TOC value we need to use.
 620                  */
 621                 __get_user(entry, (unsigned long __user *)start);
 622                 __get_user(toc, (unsigned long __user *)start+1);
 623
 624                 /* Check whether the e_entry function descriptor entries
 625                  * need to be relocated before we can use them.
 626                  */
 627                 if (load_addr != 0) {
 628                         entry += load_addr;
 629                         toc   += load_addr;
 630                 }
 631                 regs->nip = entry;
 632                 regs->gpr[2] = toc;
 633                 regs->msr = MSR_USER64;
 634         } else {
 635                 regs->nip = start;
 636                 regs->gpr[2] = 0;
 637                 regs->msr = MSR_USER32;
 638         }
 639 #endif
 640
 641 #ifndef CONFIG_SMP
 642         if (last_task_used_math == current)
 643                 last_task_used_math = NULL;
 644 #ifdef CONFIG_ALTIVEC
 645         if (last_task_used_altivec == current)
 646                 last_task_used_altivec = NULL;
 647 #endif
 648 #ifdef CONFIG_SPE
 649         if (last_task_used_spe == current)
 650                 last_task_used_spe = NULL;
 651 #endif
 652 #endif /* CONFIG_SMP */
 653         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 654         current->thread.fpscr.val = 0;
 655 #ifdef CONFIG_ALTIVEC
 656         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 657         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 658         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 659         current->thread.vrsave = 0;
 660         current->thread.used_vr = 0;
 661 #endif /* CONFIG_ALTIVEC */
 662 #ifdef CONFIG_SPE
 663         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 664         current->thread.acc = 0;
 665         current->thread.spefscr = 0;
 666         current->thread.used_spe = 0;
 667 #endif /* CONFIG_SPE */
 668 }
 669
 670 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 671                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 672
 673 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 674 {
 675         struct pt_regs *regs = tsk->thread.regs;
 676
 677         /* This is a bit hairy.  If we are an SPE enabled  processor
 678          * (have embedded fp) we store the IEEE exception enable flags in
 679          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 680          * mode (asyn, precise, disabled) for 'Classic' FP. */
 681         if (val & PR_FP_EXC_SW_ENABLE) {
 682 #ifdef CONFIG_SPE
 683                 tsk->thread.fpexc_mode = val &
 684                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 685                 return 0;
 686 #else
 687                 return -EINVAL;
 688 #endif
 689         }
 690
 691         /* on a CONFIG_SPE this does not hurt us.  The bits that
 692          * __pack_fe01 use do not overlap with bits used for
 693          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 694          * on CONFIG_SPE implementations are reserved so writing to
 695          * them does not change anything */
 696         if (val > PR_FP_EXC_PRECISE)
 697                 return -EINVAL;
 698         tsk->thread.fpexc_mode = __pack_fe01(val);
 699         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 700                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 701                         | tsk->thread.fpexc_mode;
 702         return 0;
 703 }
 704
 705 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 706 {
 707         unsigned int val;
 708
 709         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 710 #ifdef CONFIG_SPE
 711                 val = tsk->thread.fpexc_mode;
 712 #else
 713                 return -EINVAL;
 714 #endif
 715         else
 716                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 717         return put_user(val, (unsigned int __user *) adr);
 718 }
 719
 720 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
 721
 722 int sys_clone(unsigned long clone_flags, unsigned long usp,
 723               int __user *parent_tidp, void __user *child_threadptr,
 724               int __user *child_tidp, int p6,
 725               struct pt_regs *regs)
 726 {
 727         CHECK_FULL_REGS(regs);
 728         if (usp == 0)
 729                 usp = regs->gpr[1];     /* stack pointer for child */
 730 #ifdef CONFIG_PPC64
 731         if (test_thread_flag(TIF_32BIT)) {
 732                 parent_tidp = TRUNC_PTR(parent_tidp);
 733                 child_tidp = TRUNC_PTR(child_tidp);
 734         }
 735 #endif
 736         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 737 }
 738
 739 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 740              unsigned long p4, unsigned long p5, unsigned long p6,
 741              struct pt_regs *regs)
 742 {
 743         CHECK_FULL_REGS(regs);
 744         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 745 }
 746
 747 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 748               unsigned long p4, unsigned long p5, unsigned long p6,
 749               struct pt_regs *regs)
 750 {
 751         CHECK_FULL_REGS(regs);
 752         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 753                         regs, 0, NULL, NULL);
 754 }
 755
 756 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 757                unsigned long a3, unsigned long a4, unsigned long a5,
 758                struct pt_regs *regs)
 759 {
 760         int error;
 761         char *filename;
 762
 763         filename = getname((char __user *) a0);
 764         error = PTR_ERR(filename);
 765         if (IS_ERR(filename))
 766                 goto out;
 767         flush_fp_to_thread(current);
 768         flush_altivec_to_thread(current);
 769         flush_spe_to_thread(current);
 770         error = do_execve(filename, (char __user * __user *) a1,
 771                           (char __user * __user *) a2, regs);
 772         if (error == 0) {
 773                 task_lock(current);
 774                 current->ptrace &= ~PT_DTRACE;
 775                 task_unlock(current);
 776         }
 777         putname(filename);
 778 out:
 779         return error;
 780 }
 781
 782 static int validate_sp(unsigned long sp, struct task_struct *p,
 783                        unsigned long nbytes)
 784 {
 785         unsigned long stack_page = (unsigned long)p->thread_info;
 786
 787         if (sp >= stack_page + sizeof(struct thread_struct)
 788             && sp <= stack_page + THREAD_SIZE - nbytes)
 789                 return 1;
 790
 791 #ifdef CONFIG_IRQSTACKS
 792         stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
 793         if (sp >= stack_page + sizeof(struct thread_struct)
 794             && sp <= stack_page + THREAD_SIZE - nbytes)
 795                 return 1;
 796
 797         stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
 798         if (sp >= stack_page + sizeof(struct thread_struct)
 799             && sp <= stack_page + THREAD_SIZE - nbytes)
 800                 return 1;
 801 #endif
 802
 803         return 0;
 804 }
 805
 806 #ifdef CONFIG_PPC64
 807 #define MIN_STACK_FRAME 112     /* same as STACK_FRAME_OVERHEAD, in fact */
 808 #define FRAME_LR_SAVE   2
 809 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
 810 #define REGS_MARKER     0x7265677368657265ul
 811 #define FRAME_MARKER    12
 812 #else
 813 #define MIN_STACK_FRAME 16
 814 #define FRAME_LR_SAVE   1
 815 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
 816 #define REGS_MARKER     0x72656773ul
 817 #define FRAME_MARKER    2
 818 #endif
 819
 820 unsigned long get_wchan(struct task_struct *p)
 821 {
 822         unsigned long ip, sp;
 823         int count = 0;
 824
 825         if (!p || p == current || p->state == TASK_RUNNING)
 826                 return 0;
 827
 828         sp = p->thread.ksp;
 829         if (!validate_sp(sp, p, MIN_STACK_FRAME))
 830                 return 0;
 831
 832         do {
 833                 sp = *(unsigned long *)sp;
 834                 if (!validate_sp(sp, p, MIN_STACK_FRAME))
 835                         return 0;
 836                 if (count > 0) {
 837                         ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
 838                         if (!in_sched_functions(ip))
 839                                 return ip;
 840                 }
 841         } while (count++ < 16);
 842         return 0;
 843 }
 844 EXPORT_SYMBOL(get_wchan);
 845
 846 static int kstack_depth_to_print = 64;
 847
 848 void show_stack(struct task_struct *tsk, unsigned long *stack)
 849 {
 850         unsigned long sp, ip, lr, newsp;
 851         int count = 0;
 852         int firstframe = 1;
 853
 854         sp = (unsigned long) stack;
 855         if (tsk == NULL)
 856                 tsk = current;
 857         if (sp == 0) {
 858                 if (tsk == current)
 859                         asm("mr %0,1" : "=r" (sp));
 860                 else
 861                         sp = tsk->thread.ksp;
 862         }
 863
 864         lr = 0;
 865         printk("Call Trace:\n");
 866         do {
 867                 if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
 868                         return;
 869
 870                 stack = (unsigned long *) sp;
 871                 newsp = stack[0];
 872                 ip = stack[FRAME_LR_SAVE];
 873                 if (!firstframe || ip != lr) {
 874                         printk("["REG"] ["REG"] ", sp, ip);
 875                         print_symbol("%s", ip);
 876                         if (firstframe)
 877                                 printk(" (unreliable)");
 878                         printk("\n");
 879                 }
 880                 firstframe = 0;
 881
 882                 /*
 883                  * See if this is an exception frame.
 884                  * We look for the "regshere" marker in the current frame.
 885                  */
 886                 if (validate_sp(sp, tsk, INT_FRAME_SIZE)
 887                     && stack[FRAME_MARKER] == REGS_MARKER) {
 888                         struct pt_regs *regs = (struct pt_regs *)
 889                                 (sp + STACK_FRAME_OVERHEAD);
 890                         printk("--- Exception: %lx", regs->trap);
 891                         print_symbol(" at %s\n", regs->nip);
 892                         lr = regs->link;
 893                         print_symbol("    LR = %s\n", lr);
 894                         firstframe = 1;
 895                 }
 896
 897                 sp = newsp;
 898         } while (count++ < kstack_depth_to_print);
 899 }
 900
 901 void dump_stack(void)
 902 {
 903         show_stack(current, NULL);
 904 }
 905 EXPORT_SYMBOL(dump_stack);