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 #include <linux/kprobes.h>
  39
  40 #include <asm/pgtable.h>
  41 #include <asm/uaccess.h>
  42 #include <asm/system.h>
  43 #include <asm/io.h>
  44 #include <asm/processor.h>
  45 #include <asm/mmu.h>
  46 #include <asm/prom.h>
  47 #include <asm/machdep.h>
  48 #include <asm/time.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                 if (BAD_PC(pc) || __get_user(instr, (unsigned int *)pc)) {
 367                         printk("XXXXXXXX ");
 368                 } else {
 369                         if (regs->nip == pc)
 370                                 printk("<%08x> ", instr);
 371                         else
 372                                 printk("%08x ", instr);
 373                 }
 374
 375                 pc += sizeof(int);
 376         }
 377
 378         printk("\n");
 379 }
 380
 381 static struct regbit {
 382         unsigned long bit;
 383         const char *name;
 384 } msr_bits[] = {
 385         {MSR_EE,        "EE"},
 386         {MSR_PR,        "PR"},
 387         {MSR_FP,        "FP"},
 388         {MSR_ME,        "ME"},
 389         {MSR_IR,        "IR"},
 390         {MSR_DR,        "DR"},
 391         {0,             NULL}
 392 };
 393
 394 static void printbits(unsigned long val, struct regbit *bits)
 395 {
 396         const char *sep = "";
 397
 398         printk("<");
 399         for (; bits->bit; ++bits)
 400                 if (val & bits->bit) {
 401                         printk("%s%s", sep, bits->name);
 402                         sep = ",";
 403                 }
 404         printk(">");
 405 }
 406
 407 #ifdef CONFIG_PPC64
 408 #define REG             "%016lX"
 409 #define REGS_PER_LINE   4
 410 #define LAST_VOLATILE   13
 411 #else
 412 #define REG             "%08lX"
 413 #define REGS_PER_LINE   8
 414 #define LAST_VOLATILE   12
 415 #endif
 416
 417 void show_regs(struct pt_regs * regs)
 418 {
 419         int i, trap;
 420
 421         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 422                regs->nip, regs->link, regs->ctr);
 423         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 424                regs, regs->trap, print_tainted(), system_utsname.release);
 425         printk("MSR: "REG" ", regs->msr);
 426         printbits(regs->msr, msr_bits);
 427         printk("  CR: %08lX  XER: %08lX\n", regs->ccr, regs->xer);
 428         trap = TRAP(regs);
 429         if (trap == 0x300 || trap == 0x600)
 430                 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
 431         printk("TASK = %p[%d] '%s' THREAD: %p",
 432                current, current->pid, current->comm, task_thread_info(current));
 433
 434 #ifdef CONFIG_SMP
 435         printk(" CPU: %d", smp_processor_id());
 436 #endif /* CONFIG_SMP */
 437
 438         for (i = 0;  i < 32;  i++) {
 439                 if ((i % REGS_PER_LINE) == 0)
 440                         printk("\n" KERN_INFO "GPR%02d: ", i);
 441                 printk(REG " ", regs->gpr[i]);
 442                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 443                         break;
 444         }
 445         printk("\n");
 446 #ifdef CONFIG_KALLSYMS
 447         /*
 448          * Lookup NIP late so we have the best change of getting the
 449          * above info out without failing
 450          */
 451         printk("NIP ["REG"] ", regs->nip);
 452         print_symbol("%s\n", regs->nip);
 453         printk("LR ["REG"] ", regs->link);
 454         print_symbol("%s\n", regs->link);
 455 #endif
 456         show_stack(current, (unsigned long *) regs->gpr[1]);
 457         if (!user_mode(regs))
 458                 show_instructions(regs);
 459 }
 460
 461 void exit_thread(void)
 462 {
 463         kprobe_flush_task(current);
 464         discard_lazy_cpu_state();
 465 }
 466
 467 void flush_thread(void)
 468 {
 469 #ifdef CONFIG_PPC64
 470         struct thread_info *t = current_thread_info();
 471
 472         if (t->flags & _TIF_ABI_PENDING)
 473                 t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
 474 #endif
 475
 476         discard_lazy_cpu_state();
 477
 478 #ifdef CONFIG_PPC64     /* for now */
 479         if (current->thread.dabr) {
 480                 current->thread.dabr = 0;
 481                 set_dabr(0);
 482         }
 483 #endif
 484 }
 485
 486 void
 487 release_thread(struct task_struct *t)
 488 {
 489 }
 490
 491 /*
 492  * This gets called before we allocate a new thread and copy
 493  * the current task into it.
 494  */
 495 void prepare_to_copy(struct task_struct *tsk)
 496 {
 497         flush_fp_to_thread(current);
 498         flush_altivec_to_thread(current);
 499         flush_spe_to_thread(current);
 500 }
 501
 502 /*
 503  * Copy a thread..
 504  */
 505 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 506                 unsigned long unused, struct task_struct *p,
 507                 struct pt_regs *regs)
 508 {
 509         struct pt_regs *childregs, *kregs;
 510         extern void ret_from_fork(void);
 511         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 512
 513         CHECK_FULL_REGS(regs);
 514         /* Copy registers */
 515         sp -= sizeof(struct pt_regs);
 516         childregs = (struct pt_regs *) sp;
 517         *childregs = *regs;
 518         if ((childregs->msr & MSR_PR) == 0) {
 519                 /* for kernel thread, set `current' and stackptr in new task */
 520                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 521 #ifdef CONFIG_PPC32
 522                 childregs->gpr[2] = (unsigned long) p;
 523 #else
 524                 clear_tsk_thread_flag(p, TIF_32BIT);
 525 #endif
 526                 p->thread.regs = NULL;  /* no user register state */
 527         } else {
 528                 childregs->gpr[1] = usp;
 529                 p->thread.regs = childregs;
 530                 if (clone_flags & CLONE_SETTLS) {
 531 #ifdef CONFIG_PPC64
 532                         if (!test_thread_flag(TIF_32BIT))
 533                                 childregs->gpr[13] = childregs->gpr[6];
 534                         else
 535 #endif
 536                                 childregs->gpr[2] = childregs->gpr[6];
 537                 }
 538         }
 539         childregs->gpr[3] = 0;  /* Result from fork() */
 540         sp -= STACK_FRAME_OVERHEAD;
 541
 542         /*
 543          * The way this works is that at some point in the future
 544          * some task will call _switch to switch to the new task.
 545          * That will pop off the stack frame created below and start
 546          * the new task running at ret_from_fork.  The new task will
 547          * do some house keeping and then return from the fork or clone
 548          * system call, using the stack frame created above.
 549          */
 550         sp -= sizeof(struct pt_regs);
 551         kregs = (struct pt_regs *) sp;
 552         sp -= STACK_FRAME_OVERHEAD;
 553         p->thread.ksp = sp;
 554
 555 #ifdef CONFIG_PPC64
 556         if (cpu_has_feature(CPU_FTR_SLB)) {
 557                 unsigned long sp_vsid = get_kernel_vsid(sp);
 558                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 559
 560                 sp_vsid <<= SLB_VSID_SHIFT;
 561                 sp_vsid |= SLB_VSID_KERNEL | llp;
 562                 p->thread.ksp_vsid = sp_vsid;
 563         }
 564
 565         /*
 566          * The PPC64 ABI makes use of a TOC to contain function
 567          * pointers.  The function (ret_from_except) is actually a pointer
 568          * to the TOC entry.  The first entry is a pointer to the actual
 569          * function.
 570          */
 571         kregs->nip = *((unsigned long *)ret_from_fork);
 572 #else
 573         kregs->nip = (unsigned long)ret_from_fork;
 574         p->thread.last_syscall = -1;
 575 #endif
 576
 577         return 0;
 578 }
 579
 580 /*
 581  * Set up a thread for executing a new program
 582  */
 583 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 584 {
 585 #ifdef CONFIG_PPC64
 586         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 587 #endif
 588
 589         set_fs(USER_DS);
 590
 591         /*
 592          * If we exec out of a kernel thread then thread.regs will not be
 593          * set.  Do it now.
 594          */
 595         if (!current->thread.regs) {
 596                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
 597                 current->thread.regs = regs - 1;
 598         }
 599
 600         memset(regs->gpr, 0, sizeof(regs->gpr));
 601         regs->ctr = 0;
 602         regs->link = 0;
 603         regs->xer = 0;
 604         regs->ccr = 0;
 605         regs->gpr[1] = sp;
 606
 607 #ifdef CONFIG_PPC32
 608         regs->mq = 0;
 609         regs->nip = start;
 610         regs->msr = MSR_USER;
 611 #else
 612         if (!test_thread_flag(TIF_32BIT)) {
 613                 unsigned long entry, toc;
 614
 615                 /* start is a relocated pointer to the function descriptor for
 616                  * the elf _start routine.  The first entry in the function
 617                  * descriptor is the entry address of _start and the second
 618                  * entry is the TOC value we need to use.
 619                  */
 620                 __get_user(entry, (unsigned long __user *)start);
 621                 __get_user(toc, (unsigned long __user *)start+1);
 622
 623                 /* Check whether the e_entry function descriptor entries
 624                  * need to be relocated before we can use them.
 625                  */
 626                 if (load_addr != 0) {
 627                         entry += load_addr;
 628                         toc   += load_addr;
 629                 }
 630                 regs->nip = entry;
 631                 regs->gpr[2] = toc;
 632                 regs->msr = MSR_USER64;
 633         } else {
 634                 regs->nip = start;
 635                 regs->gpr[2] = 0;
 636                 regs->msr = MSR_USER32;
 637         }
 638 #endif
 639
 640         discard_lazy_cpu_state();
 641         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 642         current->thread.fpscr.val = 0;
 643 #ifdef CONFIG_ALTIVEC
 644         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 645         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 646         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 647         current->thread.vrsave = 0;
 648         current->thread.used_vr = 0;
 649 #endif /* CONFIG_ALTIVEC */
 650 #ifdef CONFIG_SPE
 651         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 652         current->thread.acc = 0;
 653         current->thread.spefscr = 0;
 654         current->thread.used_spe = 0;
 655 #endif /* CONFIG_SPE */
 656 }
 657
 658 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 659                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 660
 661 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 662 {
 663         struct pt_regs *regs = tsk->thread.regs;
 664
 665         /* This is a bit hairy.  If we are an SPE enabled  processor
 666          * (have embedded fp) we store the IEEE exception enable flags in
 667          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 668          * mode (asyn, precise, disabled) for 'Classic' FP. */
 669         if (val & PR_FP_EXC_SW_ENABLE) {
 670 #ifdef CONFIG_SPE
 671                 tsk->thread.fpexc_mode = val &
 672                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 673                 return 0;
 674 #else
 675                 return -EINVAL;
 676 #endif
 677         }
 678
 679         /* on a CONFIG_SPE this does not hurt us.  The bits that
 680          * __pack_fe01 use do not overlap with bits used for
 681          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 682          * on CONFIG_SPE implementations are reserved so writing to
 683          * them does not change anything */
 684         if (val > PR_FP_EXC_PRECISE)
 685                 return -EINVAL;
 686         tsk->thread.fpexc_mode = __pack_fe01(val);
 687         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 688                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 689                         | tsk->thread.fpexc_mode;
 690         return 0;
 691 }
 692
 693 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 694 {
 695         unsigned int val;
 696
 697         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 698 #ifdef CONFIG_SPE
 699                 val = tsk->thread.fpexc_mode;
 700 #else
 701                 return -EINVAL;
 702 #endif
 703         else
 704                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 705         return put_user(val, (unsigned int __user *) adr);
 706 }
 707
 708 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
 709
 710 int sys_clone(unsigned long clone_flags, unsigned long usp,
 711               int __user *parent_tidp, void __user *child_threadptr,
 712               int __user *child_tidp, int p6,
 713               struct pt_regs *regs)
 714 {
 715         CHECK_FULL_REGS(regs);
 716         if (usp == 0)
 717                 usp = regs->gpr[1];     /* stack pointer for child */
 718 #ifdef CONFIG_PPC64
 719         if (test_thread_flag(TIF_32BIT)) {
 720                 parent_tidp = TRUNC_PTR(parent_tidp);
 721                 child_tidp = TRUNC_PTR(child_tidp);
 722         }
 723 #endif
 724         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 725 }
 726
 727 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 728              unsigned long p4, unsigned long p5, unsigned long p6,
 729              struct pt_regs *regs)
 730 {
 731         CHECK_FULL_REGS(regs);
 732         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 733 }
 734
 735 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 736               unsigned long p4, unsigned long p5, unsigned long p6,
 737               struct pt_regs *regs)
 738 {
 739         CHECK_FULL_REGS(regs);
 740         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 741                         regs, 0, NULL, NULL);
 742 }
 743
 744 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 745                unsigned long a3, unsigned long a4, unsigned long a5,
 746                struct pt_regs *regs)
 747 {
 748         int error;
 749         char *filename;
 750
 751         filename = getname((char __user *) a0);
 752         error = PTR_ERR(filename);
 753         if (IS_ERR(filename))
 754                 goto out;
 755         flush_fp_to_thread(current);
 756         flush_altivec_to_thread(current);
 757         flush_spe_to_thread(current);
 758         error = do_execve(filename, (char __user * __user *) a1,
 759                           (char __user * __user *) a2, regs);
 760         if (error == 0) {
 761                 task_lock(current);
 762                 current->ptrace &= ~PT_DTRACE;
 763                 task_unlock(current);
 764         }
 765         putname(filename);
 766 out:
 767         return error;
 768 }
 769
 770 static int validate_sp(unsigned long sp, struct task_struct *p,
 771                        unsigned long nbytes)
 772 {
 773         unsigned long stack_page = (unsigned long)task_stack_page(p);
 774
 775         if (sp >= stack_page + sizeof(struct thread_struct)
 776             && sp <= stack_page + THREAD_SIZE - nbytes)
 777                 return 1;
 778
 779 #ifdef CONFIG_IRQSTACKS
 780         stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
 781         if (sp >= stack_page + sizeof(struct thread_struct)
 782             && sp <= stack_page + THREAD_SIZE - nbytes)
 783                 return 1;
 784
 785         stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
 786         if (sp >= stack_page + sizeof(struct thread_struct)
 787             && sp <= stack_page + THREAD_SIZE - nbytes)
 788                 return 1;
 789 #endif
 790
 791         return 0;
 792 }
 793
 794 #ifdef CONFIG_PPC64
 795 #define MIN_STACK_FRAME 112     /* same as STACK_FRAME_OVERHEAD, in fact */
 796 #define FRAME_LR_SAVE   2
 797 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
 798 #define REGS_MARKER     0x7265677368657265ul
 799 #define FRAME_MARKER    12
 800 #else
 801 #define MIN_STACK_FRAME 16
 802 #define FRAME_LR_SAVE   1
 803 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
 804 #define REGS_MARKER     0x72656773ul
 805 #define FRAME_MARKER    2
 806 #endif
 807
 808 unsigned long get_wchan(struct task_struct *p)
 809 {
 810         unsigned long ip, sp;
 811         int count = 0;
 812
 813         if (!p || p == current || p->state == TASK_RUNNING)
 814                 return 0;
 815
 816         sp = p->thread.ksp;
 817         if (!validate_sp(sp, p, MIN_STACK_FRAME))
 818                 return 0;
 819
 820         do {
 821                 sp = *(unsigned long *)sp;
 822                 if (!validate_sp(sp, p, MIN_STACK_FRAME))
 823                         return 0;
 824                 if (count > 0) {
 825                         ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
 826                         if (!in_sched_functions(ip))
 827                                 return ip;
 828                 }
 829         } while (count++ < 16);
 830         return 0;
 831 }
 832 EXPORT_SYMBOL(get_wchan);
 833
 834 static int kstack_depth_to_print = 64;
 835
 836 void show_stack(struct task_struct *tsk, unsigned long *stack)
 837 {
 838         unsigned long sp, ip, lr, newsp;
 839         int count = 0;
 840         int firstframe = 1;
 841
 842         sp = (unsigned long) stack;
 843         if (tsk == NULL)
 844                 tsk = current;
 845         if (sp == 0) {
 846                 if (tsk == current)
 847                         asm("mr %0,1" : "=r" (sp));
 848                 else
 849                         sp = tsk->thread.ksp;
 850         }
 851
 852         lr = 0;
 853         printk("Call Trace:\n");
 854         do {
 855                 if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
 856                         return;
 857
 858                 stack = (unsigned long *) sp;
 859                 newsp = stack[0];
 860                 ip = stack[FRAME_LR_SAVE];
 861                 if (!firstframe || ip != lr) {
 862                         printk("["REG"] ["REG"] ", sp, ip);
 863                         print_symbol("%s", ip);
 864                         if (firstframe)
 865                                 printk(" (unreliable)");
 866                         printk("\n");
 867                 }
 868                 firstframe = 0;
 869
 870                 /*
 871                  * See if this is an exception frame.
 872                  * We look for the "regshere" marker in the current frame.
 873                  */
 874                 if (validate_sp(sp, tsk, INT_FRAME_SIZE)
 875                     && stack[FRAME_MARKER] == REGS_MARKER) {
 876                         struct pt_regs *regs = (struct pt_regs *)
 877                                 (sp + STACK_FRAME_OVERHEAD);
 878                         printk("--- Exception: %lx", regs->trap);
 879                         print_symbol(" at %s\n", regs->nip);
 880                         lr = regs->link;
 881                         print_symbol("    LR = %s\n", lr);
 882                         firstframe = 1;
 883                 }
 884
 885                 sp = newsp;
 886         } while (count++ < kstack_depth_to_print);
 887 }
 888
 889 void dump_stack(void)
 890 {
 891         show_stack(current, NULL);
 892 }
 893 EXPORT_SYMBOL(dump_stack);
 894
 895 #ifdef CONFIG_PPC64
 896 void ppc64_runlatch_on(void)
 897 {
 898         unsigned long ctrl;
 899
 900         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
 901                 HMT_medium();
 902
 903                 ctrl = mfspr(SPRN_CTRLF);
 904                 ctrl |= CTRL_RUNLATCH;
 905                 mtspr(SPRN_CTRLT, ctrl);
 906
 907                 set_thread_flag(TIF_RUNLATCH);
 908         }
 909 }
 910
 911 void ppc64_runlatch_off(void)
 912 {
 913         unsigned long ctrl;
 914
 915         if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) {
 916                 HMT_medium();
 917
 918                 clear_thread_flag(TIF_RUNLATCH);
 919
 920                 ctrl = mfspr(SPRN_CTRLF);
 921                 ctrl &= ~CTRL_RUNLATCH;
 922                 mtspr(SPRN_CTRLT, ctrl);
 923         }
 924 }
 925 #endif