arch/powerpc/kernel/process.c

   1 /*
   2  *  arch/ppc/kernel/process.c
   3  *
   4  *  Derived from "arch/i386/kernel/process.c"
   5  *    Copyright (C) 1995  Linus Torvalds
   6  *
   7  *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
   8  *  Paul Mackerras (paulus@cs.anu.edu.au)
   9  *
  10  *  PowerPC version
  11  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  12  *
  13  *  This program is free software; you can redistribute it and/or
  14  *  modify it under the terms of the GNU General Public License
  15  *  as published by the Free Software Foundation; either version
  16  *  2 of the License, or (at your option) any later version.
  17  */
  18
  19 #include <linux/config.h>
  20 #include <linux/errno.h>
  21 #include <linux/sched.h>
  22 #include <linux/kernel.h>
  23 #include <linux/mm.h>
  24 #include <linux/smp.h>
  25 #include <linux/smp_lock.h>
  26 #include <linux/stddef.h>
  27 #include <linux/unistd.h>
  28 #include <linux/ptrace.h>
  29 #include <linux/slab.h>
  30 #include <linux/user.h>
  31 #include <linux/elf.h>
  32 #include <linux/init.h>
  33 #include <linux/prctl.h>
  34 #include <linux/init_task.h>
  35 #include <linux/module.h>
  36 #include <linux/kallsyms.h>
  37 #include <linux/mqueue.h>
  38 #include <linux/hardirq.h>
  39 #include <linux/utsname.h>
  40 #include <linux/kprobes.h>
  41
  42 #include <asm/pgtable.h>
  43 #include <asm/uaccess.h>
  44 #include <asm/system.h>
  45 #include <asm/io.h>
  46 #include <asm/processor.h>
  47 #include <asm/mmu.h>
  48 #include <asm/prom.h>
  49 #include <asm/machdep.h>
  50 #ifdef CONFIG_PPC64
  51 #include <asm/firmware.h>
  52 #include <asm/time.h>
  53 #endif
  54
  55 extern unsigned long _get_SP(void);
  56
  57 #ifndef CONFIG_SMP
  58 struct task_struct *last_task_used_math = NULL;
  59 struct task_struct *last_task_used_altivec = NULL;
  60 struct task_struct *last_task_used_spe = NULL;
  61 #endif
  62
  63 /*
  64  * Make sure the floating-point register state in the
  65  * the thread_struct is up to date for task tsk.
  66  */
  67 void flush_fp_to_thread(struct task_struct *tsk)
  68 {
  69         if (tsk->thread.regs) {
  70                 /*
  71                  * We need to disable preemption here because if we didn't,
  72                  * another process could get scheduled after the regs->msr
  73                  * test but before we have finished saving the FP registers
  74                  * to the thread_struct.  That process could take over the
  75                  * FPU, and then when we get scheduled again we would store
  76                  * bogus values for the remaining FP registers.
  77                  */
  78                 preempt_disable();
  79                 if (tsk->thread.regs->msr & MSR_FP) {
  80 #ifdef CONFIG_SMP
  81                         /*
  82                          * This should only ever be called for current or
  83                          * for a stopped child process.  Since we save away
  84                          * the FP register state on context switch on SMP,
  85                          * there is something wrong if a stopped child appears
  86                          * to still have its FP state in the CPU registers.
  87                          */
  88                         BUG_ON(tsk != current);
  89 #endif
  90                         giveup_fpu(current);
  91                 }
  92                 preempt_enable();
  93         }
  94 }
  95
  96 void enable_kernel_fp(void)
  97 {
  98         WARN_ON(preemptible());
  99
 100 #ifdef CONFIG_SMP
 101         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 102                 giveup_fpu(current);
 103         else
 104                 giveup_fpu(NULL);       /* just enables FP for kernel */
 105 #else
 106         giveup_fpu(last_task_used_math);
 107 #endif /* CONFIG_SMP */
 108 }
 109 EXPORT_SYMBOL(enable_kernel_fp);
 110
 111 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
 112 {
 113         if (!tsk->thread.regs)
 114                 return 0;
 115         flush_fp_to_thread(current);
 116
 117         memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
 118
 119         return 1;
 120 }
 121
 122 #ifdef CONFIG_ALTIVEC
 123 void enable_kernel_altivec(void)
 124 {
 125         WARN_ON(preemptible());
 126
 127 #ifdef CONFIG_SMP
 128         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 129                 giveup_altivec(current);
 130         else
 131                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 132 #else
 133         giveup_altivec(last_task_used_altivec);
 134 #endif /* CONFIG_SMP */
 135 }
 136 EXPORT_SYMBOL(enable_kernel_altivec);
 137
 138 /*
 139  * Make sure the VMX/Altivec register state in the
 140  * the thread_struct is up to date for task tsk.
 141  */
 142 void flush_altivec_to_thread(struct task_struct *tsk)
 143 {
 144         if (tsk->thread.regs) {
 145                 preempt_disable();
 146                 if (tsk->thread.regs->msr & MSR_VEC) {
 147 #ifdef CONFIG_SMP
 148                         BUG_ON(tsk != current);
 149 #endif
 150                         giveup_altivec(current);
 151                 }
 152                 preempt_enable();
 153         }
 154 }
 155
 156 int dump_task_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
 157 {
 158         flush_altivec_to_thread(current);
 159         memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
 160         return 1;
 161 }
 162 #endif /* CONFIG_ALTIVEC */
 163
 164 #ifdef CONFIG_SPE
 165
 166 void enable_kernel_spe(void)
 167 {
 168         WARN_ON(preemptible());
 169
 170 #ifdef CONFIG_SMP
 171         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 172                 giveup_spe(current);
 173         else
 174                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 175 #else
 176         giveup_spe(last_task_used_spe);
 177 #endif /* __SMP __ */
 178 }
 179 EXPORT_SYMBOL(enable_kernel_spe);
 180
 181 void flush_spe_to_thread(struct task_struct *tsk)
 182 {
 183         if (tsk->thread.regs) {
 184                 preempt_disable();
 185                 if (tsk->thread.regs->msr & MSR_SPE) {
 186 #ifdef CONFIG_SMP
 187                         BUG_ON(tsk != current);
 188 #endif
 189                         giveup_spe(current);
 190                 }
 191                 preempt_enable();
 192         }
 193 }
 194
 195 int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 196 {
 197         flush_spe_to_thread(current);
 198         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
 199         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
 200         return 1;
 201 }
 202 #endif /* CONFIG_SPE */
 203
 204 #ifndef CONFIG_SMP
 205 /*
 206  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 207  * and the current task has some state, discard it.
 208  */
 209 void discard_lazy_cpu_state(void)
 210 {
 211         preempt_disable();
 212         if (last_task_used_math == current)
 213                 last_task_used_math = NULL;
 214 #ifdef CONFIG_ALTIVEC
 215         if (last_task_used_altivec == current)
 216                 last_task_used_altivec = NULL;
 217 #endif /* CONFIG_ALTIVEC */
 218 #ifdef CONFIG_SPE
 219         if (last_task_used_spe == current)
 220                 last_task_used_spe = NULL;
 221 #endif
 222         preempt_enable();
 223 }
 224 #endif /* CONFIG_SMP */
 225
 226 #ifdef CONFIG_PPC_MERGE         /* XXX for now */
 227 int set_dabr(unsigned long dabr)
 228 {
 229         if (ppc_md.set_dabr)
 230                 return ppc_md.set_dabr(dabr);
 231
 232         mtspr(SPRN_DABR, dabr);
 233         return 0;
 234 }
 235 #endif
 236
 237 #ifdef CONFIG_PPC64
 238 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 239 static DEFINE_PER_CPU(unsigned long, current_dabr);
 240 #endif
 241
 242 struct task_struct *__switch_to(struct task_struct *prev,
 243         struct task_struct *new)
 244 {
 245         struct thread_struct *new_thread, *old_thread;
 246         unsigned long flags;
 247         struct task_struct *last;
 248
 249 #ifdef CONFIG_SMP
 250         /* avoid complexity of lazy save/restore of fpu
 251          * by just saving it every time we switch out if
 252          * this task used the fpu during the last quantum.
 253          *
 254          * If it tries to use the fpu again, it'll trap and
 255          * reload its fp regs.  So we don't have to do a restore
 256          * every switch, just a save.
 257          *  -- Cort
 258          */
 259         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 260                 giveup_fpu(prev);
 261 #ifdef CONFIG_ALTIVEC
 262         /*
 263          * If the previous thread used altivec in the last quantum
 264          * (thus changing altivec regs) then save them.
 265          * We used to check the VRSAVE register but not all apps
 266          * set it, so we don't rely on it now (and in fact we need
 267          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 268          *
 269          * On SMP we always save/restore altivec regs just to avoid the
 270          * complexity of changing processors.
 271          *  -- Cort
 272          */
 273         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 274                 giveup_altivec(prev);
 275 #endif /* CONFIG_ALTIVEC */
 276 #ifdef CONFIG_SPE
 277         /*
 278          * If the previous thread used spe in the last quantum
 279          * (thus changing spe regs) then save them.
 280          *
 281          * On SMP we always save/restore spe regs just to avoid the
 282          * complexity of changing processors.
 283          */
 284         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 285                 giveup_spe(prev);
 286 #endif /* CONFIG_SPE */
 287
 288 #else  /* CONFIG_SMP */
 289 #ifdef CONFIG_ALTIVEC
 290         /* Avoid the trap.  On smp this this never happens since
 291          * we don't set last_task_used_altivec -- Cort
 292          */
 293         if (new->thread.regs && last_task_used_altivec == new)
 294                 new->thread.regs->msr |= MSR_VEC;
 295 #endif /* CONFIG_ALTIVEC */
 296 #ifdef CONFIG_SPE
 297         /* Avoid the trap.  On smp this this never happens since
 298          * we don't set last_task_used_spe
 299          */
 300         if (new->thread.regs && last_task_used_spe == new)
 301                 new->thread.regs->msr |= MSR_SPE;
 302 #endif /* CONFIG_SPE */
 303
 304 #endif /* CONFIG_SMP */
 305
 306 #ifdef CONFIG_PPC64     /* for now */
 307         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
 308                 set_dabr(new->thread.dabr);
 309                 __get_cpu_var(current_dabr) = new->thread.dabr;
 310         }
 311
 312         flush_tlb_pending();
 313 #endif
 314
 315         new_thread = &new->thread;
 316         old_thread = &current->thread;
 317
 318 #ifdef CONFIG_PPC64
 319         /*
 320          * Collect processor utilization data per process
 321          */
 322         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 323                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 324                 long unsigned start_tb, current_tb;
 325                 start_tb = old_thread->start_tb;
 326                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 327                 old_thread->accum_tb += (current_tb - start_tb);
 328                 new_thread->start_tb = current_tb;
 329         }
 330 #endif
 331
 332         local_irq_save(flags);
 333         last = _switch(old_thread, new_thread);
 334
 335         local_irq_restore(flags);
 336
 337         return last;
 338 }
 339
 340 static int instructions_to_print = 16;
 341
 342 #ifdef CONFIG_PPC64
 343 #define BAD_PC(pc)      ((REGION_ID(pc) != KERNEL_REGION_ID) && \
 344                          (REGION_ID(pc) != VMALLOC_REGION_ID))
 345 #else
 346 #define BAD_PC(pc)      ((pc) < KERNELBASE)
 347 #endif
 348
 349 static void show_instructions(struct pt_regs *regs)
 350 {
 351         int i;
 352         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 353                         sizeof(int));
 354
 355         printk("Instruction dump:");
 356
 357         for (i = 0; i < instructions_to_print; i++) {
 358                 int instr;
 359
 360                 if (!(i % 8))
 361                         printk("\n");
 362
 363                 if (BAD_PC(pc) || __get_user(instr, (unsigned int *)pc)) {
 364                         printk("XXXXXXXX ");
 365                 } else {
 366                         if (regs->nip == pc)
 367                                 printk("<%08x> ", instr);
 368                         else
 369                                 printk("%08x ", instr);
 370                 }
 371
 372                 pc += sizeof(int);
 373         }
 374
 375         printk("\n");
 376 }
 377
 378 static struct regbit {
 379         unsigned long bit;
 380         const char *name;
 381 } msr_bits[] = {
 382         {MSR_EE,        "EE"},
 383         {MSR_PR,        "PR"},
 384         {MSR_FP,        "FP"},
 385         {MSR_ME,        "ME"},
 386         {MSR_IR,        "IR"},
 387         {MSR_DR,        "DR"},
 388         {0,             NULL}
 389 };
 390
 391 static void printbits(unsigned long val, struct regbit *bits)
 392 {
 393         const char *sep = "";
 394
 395         printk("<");
 396         for (; bits->bit; ++bits)
 397                 if (val & bits->bit) {
 398                         printk("%s%s", sep, bits->name);
 399                         sep = ",";
 400                 }
 401         printk(">");
 402 }
 403
 404 #ifdef CONFIG_PPC64
 405 #define REG             "%016lX"
 406 #define REGS_PER_LINE   4
 407 #define LAST_VOLATILE   13
 408 #else
 409 #define REG             "%08lX"
 410 #define REGS_PER_LINE   8
 411 #define LAST_VOLATILE   12
 412 #endif
 413
 414 void show_regs(struct pt_regs * regs)
 415 {
 416         int i, trap;
 417
 418         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 419                regs->nip, regs->link, regs->ctr);
 420         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 421                regs, regs->trap, print_tainted(), system_utsname.release);
 422         printk("MSR: "REG" ", regs->msr);
 423         printbits(regs->msr, msr_bits);
 424         printk("  CR: %08lX  XER: %08lX\n", regs->ccr, regs->xer);
 425         trap = TRAP(regs);
 426         if (trap == 0x300 || trap == 0x600)
 427                 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
 428         printk("TASK = %p[%d] '%s' THREAD: %p",
 429                current, current->pid, current->comm, task_thread_info(current));
 430
 431 #ifdef CONFIG_SMP
 432         printk(" CPU: %d", smp_processor_id());
 433 #endif /* CONFIG_SMP */
 434
 435         for (i = 0;  i < 32;  i++) {
 436                 if ((i % REGS_PER_LINE) == 0)
 437                         printk("\n" KERN_INFO "GPR%02d: ", i);
 438                 printk(REG " ", regs->gpr[i]);
 439                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 440                         break;
 441         }
 442         printk("\n");
 443 #ifdef CONFIG_KALLSYMS
 444         /*
 445          * Lookup NIP late so we have the best change of getting the
 446          * above info out without failing
 447          */
 448         printk("NIP ["REG"] ", regs->nip);
 449         print_symbol("%s\n", regs->nip);
 450         printk("LR ["REG"] ", regs->link);
 451         print_symbol("%s\n", regs->link);
 452 #endif
 453         show_stack(current, (unsigned long *) regs->gpr[1]);
 454         if (!user_mode(regs))
 455                 show_instructions(regs);
 456 }
 457
 458 void exit_thread(void)
 459 {
 460         kprobe_flush_task(current);
 461         discard_lazy_cpu_state();
 462 }
 463
 464 void flush_thread(void)
 465 {
 466 #ifdef CONFIG_PPC64
 467         struct thread_info *t = current_thread_info();
 468
 469         if (t->flags & _TIF_ABI_PENDING)
 470                 t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
 471 #endif
 472
 473         discard_lazy_cpu_state();
 474
 475 #ifdef CONFIG_PPC64     /* for now */
 476         if (current->thread.dabr) {
 477                 current->thread.dabr = 0;
 478                 set_dabr(0);
 479         }
 480 #endif
 481 }
 482
 483 void
 484 release_thread(struct task_struct *t)
 485 {
 486 }
 487
 488 /*
 489  * This gets called before we allocate a new thread and copy
 490  * the current task into it.
 491  */
 492 void prepare_to_copy(struct task_struct *tsk)
 493 {
 494         flush_fp_to_thread(current);
 495         flush_altivec_to_thread(current);
 496         flush_spe_to_thread(current);
 497 }
 498
 499 /*
 500  * Copy a thread..
 501  */
 502 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 503                 unsigned long unused, struct task_struct *p,
 504                 struct pt_regs *regs)
 505 {
 506         struct pt_regs *childregs, *kregs;
 507         extern void ret_from_fork(void);
 508         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 509
 510         CHECK_FULL_REGS(regs);
 511         /* Copy registers */
 512         sp -= sizeof(struct pt_regs);
 513         childregs = (struct pt_regs *) sp;
 514         *childregs = *regs;
 515         if ((childregs->msr & MSR_PR) == 0) {
 516                 /* for kernel thread, set `current' and stackptr in new task */
 517                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 518 #ifdef CONFIG_PPC32
 519                 childregs->gpr[2] = (unsigned long) p;
 520 #else
 521                 clear_tsk_thread_flag(p, TIF_32BIT);
 522 #endif
 523                 p->thread.regs = NULL;  /* no user register state */
 524         } else {
 525                 childregs->gpr[1] = usp;
 526                 p->thread.regs = childregs;
 527                 if (clone_flags & CLONE_SETTLS) {
 528 #ifdef CONFIG_PPC64
 529                         if (!test_thread_flag(TIF_32BIT))
 530                                 childregs->gpr[13] = childregs->gpr[6];
 531                         else
 532 #endif
 533                                 childregs->gpr[2] = childregs->gpr[6];
 534                 }
 535         }
 536         childregs->gpr[3] = 0;  /* Result from fork() */
 537         sp -= STACK_FRAME_OVERHEAD;
 538
 539         /*
 540          * The way this works is that at some point in the future
 541          * some task will call _switch to switch to the new task.
 542          * That will pop off the stack frame created below and start
 543          * the new task running at ret_from_fork.  The new task will
 544          * do some house keeping and then return from the fork or clone
 545          * system call, using the stack frame created above.
 546          */
 547         sp -= sizeof(struct pt_regs);
 548         kregs = (struct pt_regs *) sp;
 549         sp -= STACK_FRAME_OVERHEAD;
 550         p->thread.ksp = sp;
 551
 552 #ifdef CONFIG_PPC64
 553         if (cpu_has_feature(CPU_FTR_SLB)) {
 554                 unsigned long sp_vsid = get_kernel_vsid(sp);
 555                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 556
 557                 sp_vsid <<= SLB_VSID_SHIFT;
 558                 sp_vsid |= SLB_VSID_KERNEL | llp;
 559                 p->thread.ksp_vsid = sp_vsid;
 560         }
 561
 562         /*
 563          * The PPC64 ABI makes use of a TOC to contain function
 564          * pointers.  The function (ret_from_except) is actually a pointer
 565          * to the TOC entry.  The first entry is a pointer to the actual
 566          * function.
 567          */
 568         kregs->nip = *((unsigned long *)ret_from_fork);
 569 #else
 570         kregs->nip = (unsigned long)ret_from_fork;
 571         p->thread.last_syscall = -1;
 572 #endif
 573
 574         return 0;
 575 }
 576
 577 /*
 578  * Set up a thread for executing a new program
 579  */
 580 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 581 {
 582 #ifdef CONFIG_PPC64
 583         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 584 #endif
 585
 586         set_fs(USER_DS);
 587
 588         /*
 589          * If we exec out of a kernel thread then thread.regs will not be
 590          * set.  Do it now.
 591          */
 592         if (!current->thread.regs) {
 593                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
 594                 current->thread.regs = regs - 1;
 595         }
 596
 597         memset(regs->gpr, 0, sizeof(regs->gpr));
 598         regs->ctr = 0;
 599         regs->link = 0;
 600         regs->xer = 0;
 601         regs->ccr = 0;
 602         regs->gpr[1] = sp;
 603
 604 #ifdef CONFIG_PPC32
 605         regs->mq = 0;
 606         regs->nip = start;
 607         regs->msr = MSR_USER;
 608 #else
 609         if (!test_thread_flag(TIF_32BIT)) {
 610                 unsigned long entry, toc;
 611
 612                 /* start is a relocated pointer to the function descriptor for
 613                  * the elf _start routine.  The first entry in the function
 614                  * descriptor is the entry address of _start and the second
 615                  * entry is the TOC value we need to use.
 616                  */
 617                 __get_user(entry, (unsigned long __user *)start);
 618                 __get_user(toc, (unsigned long __user *)start+1);
 619
 620                 /* Check whether the e_entry function descriptor entries
 621                  * need to be relocated before we can use them.
 622                  */
 623                 if (load_addr != 0) {
 624                         entry += load_addr;
 625                         toc   += load_addr;
 626                 }
 627                 regs->nip = entry;
 628                 regs->gpr[2] = toc;
 629                 regs->msr = MSR_USER64;
 630         } else {
 631                 regs->nip = start;
 632                 regs->gpr[2] = 0;
 633                 regs->msr = MSR_USER32;
 634         }
 635 #endif
 636
 637         discard_lazy_cpu_state();
 638         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 639         current->thread.fpscr.val = 0;
 640 #ifdef CONFIG_ALTIVEC
 641         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 642         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 643         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 644         current->thread.vrsave = 0;
 645         current->thread.used_vr = 0;
 646 #endif /* CONFIG_ALTIVEC */
 647 #ifdef CONFIG_SPE
 648         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 649         current->thread.acc = 0;
 650         current->thread.spefscr = 0;
 651         current->thread.used_spe = 0;
 652 #endif /* CONFIG_SPE */
 653 }
 654
 655 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 656                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 657
 658 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 659 {
 660         struct pt_regs *regs = tsk->thread.regs;
 661
 662         /* This is a bit hairy.  If we are an SPE enabled  processor
 663          * (have embedded fp) we store the IEEE exception enable flags in
 664          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 665          * mode (asyn, precise, disabled) for 'Classic' FP. */
 666         if (val & PR_FP_EXC_SW_ENABLE) {
 667 #ifdef CONFIG_SPE
 668                 tsk->thread.fpexc_mode = val &
 669                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 670                 return 0;
 671 #else
 672                 return -EINVAL;
 673 #endif
 674         }
 675
 676         /* on a CONFIG_SPE this does not hurt us.  The bits that
 677          * __pack_fe01 use do not overlap with bits used for
 678          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 679          * on CONFIG_SPE implementations are reserved so writing to
 680          * them does not change anything */
 681         if (val > PR_FP_EXC_PRECISE)
 682                 return -EINVAL;
 683         tsk->thread.fpexc_mode = __pack_fe01(val);
 684         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 685                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 686                         | tsk->thread.fpexc_mode;
 687         return 0;
 688 }
 689
 690 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 691 {
 692         unsigned int val;
 693
 694         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 695 #ifdef CONFIG_SPE
 696                 val = tsk->thread.fpexc_mode;
 697 #else
 698                 return -EINVAL;
 699 #endif
 700         else
 701                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 702         return put_user(val, (unsigned int __user *) adr);
 703 }
 704
 705 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
 706
 707 int sys_clone(unsigned long clone_flags, unsigned long usp,
 708               int __user *parent_tidp, void __user *child_threadptr,
 709               int __user *child_tidp, int p6,
 710               struct pt_regs *regs)
 711 {
 712         CHECK_FULL_REGS(regs);
 713         if (usp == 0)
 714                 usp = regs->gpr[1];     /* stack pointer for child */
 715 #ifdef CONFIG_PPC64
 716         if (test_thread_flag(TIF_32BIT)) {
 717                 parent_tidp = TRUNC_PTR(parent_tidp);
 718                 child_tidp = TRUNC_PTR(child_tidp);
 719         }
 720 #endif
 721         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 722 }
 723
 724 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 725              unsigned long p4, unsigned long p5, unsigned long p6,
 726              struct pt_regs *regs)
 727 {
 728         CHECK_FULL_REGS(regs);
 729         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 730 }
 731
 732 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 733               unsigned long p4, unsigned long p5, unsigned long p6,
 734               struct pt_regs *regs)
 735 {
 736         CHECK_FULL_REGS(regs);
 737         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 738                         regs, 0, NULL, NULL);
 739 }
 740
 741 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 742                unsigned long a3, unsigned long a4, unsigned long a5,
 743                struct pt_regs *regs)
 744 {
 745         int error;
 746         char *filename;
 747
 748         filename = getname((char __user *) a0);
 749         error = PTR_ERR(filename);
 750         if (IS_ERR(filename))
 751                 goto out;
 752         flush_fp_to_thread(current);
 753         flush_altivec_to_thread(current);
 754         flush_spe_to_thread(current);
 755         error = do_execve(filename, (char __user * __user *) a1,
 756                           (char __user * __user *) a2, regs);
 757         if (error == 0) {
 758                 task_lock(current);
 759                 current->ptrace &= ~PT_DTRACE;
 760                 task_unlock(current);
 761         }
 762         putname(filename);
 763 out:
 764         return error;
 765 }
 766
 767 static int validate_sp(unsigned long sp, struct task_struct *p,
 768                        unsigned long nbytes)
 769 {
 770         unsigned long stack_page = (unsigned long)task_stack_page(p);
 771
 772         if (sp >= stack_page + sizeof(struct thread_struct)
 773             && sp <= stack_page + THREAD_SIZE - nbytes)
 774                 return 1;
 775
 776 #ifdef CONFIG_IRQSTACKS
 777         stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
 778         if (sp >= stack_page + sizeof(struct thread_struct)
 779             && sp <= stack_page + THREAD_SIZE - nbytes)
 780                 return 1;
 781
 782         stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
 783         if (sp >= stack_page + sizeof(struct thread_struct)
 784             && sp <= stack_page + THREAD_SIZE - nbytes)
 785                 return 1;
 786 #endif
 787
 788         return 0;
 789 }
 790
 791 #ifdef CONFIG_PPC64
 792 #define MIN_STACK_FRAME 112     /* same as STACK_FRAME_OVERHEAD, in fact */
 793 #define FRAME_LR_SAVE   2
 794 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
 795 #define REGS_MARKER     0x7265677368657265ul
 796 #define FRAME_MARKER    12
 797 #else
 798 #define MIN_STACK_FRAME 16
 799 #define FRAME_LR_SAVE   1
 800 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
 801 #define REGS_MARKER     0x72656773ul
 802 #define FRAME_MARKER    2
 803 #endif
 804
 805 unsigned long get_wchan(struct task_struct *p)
 806 {
 807         unsigned long ip, sp;
 808         int count = 0;
 809
 810         if (!p || p == current || p->state == TASK_RUNNING)
 811                 return 0;
 812
 813         sp = p->thread.ksp;
 814         if (!validate_sp(sp, p, MIN_STACK_FRAME))
 815                 return 0;
 816
 817         do {
 818                 sp = *(unsigned long *)sp;
 819                 if (!validate_sp(sp, p, MIN_STACK_FRAME))
 820                         return 0;
 821                 if (count > 0) {
 822                         ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
 823                         if (!in_sched_functions(ip))
 824                                 return ip;
 825                 }
 826         } while (count++ < 16);
 827         return 0;
 828 }
 829 EXPORT_SYMBOL(get_wchan);
 830
 831 static int kstack_depth_to_print = 64;
 832
 833 void show_stack(struct task_struct *tsk, unsigned long *stack)
 834 {
 835         unsigned long sp, ip, lr, newsp;
 836         int count = 0;
 837         int firstframe = 1;
 838
 839         sp = (unsigned long) stack;
 840         if (tsk == NULL)
 841                 tsk = current;
 842         if (sp == 0) {
 843                 if (tsk == current)
 844                         asm("mr %0,1" : "=r" (sp));
 845                 else
 846                         sp = tsk->thread.ksp;
 847         }
 848
 849         lr = 0;
 850         printk("Call Trace:\n");
 851         do {
 852                 if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
 853                         return;
 854
 855                 stack = (unsigned long *) sp;
 856                 newsp = stack[0];
 857                 ip = stack[FRAME_LR_SAVE];
 858                 if (!firstframe || ip != lr) {
 859                         printk("["REG"] ["REG"] ", sp, ip);
 860                         print_symbol("%s", ip);
 861                         if (firstframe)
 862                                 printk(" (unreliable)");
 863                         printk("\n");
 864                 }
 865                 firstframe = 0;
 866
 867                 /*
 868                  * See if this is an exception frame.
 869                  * We look for the "regshere" marker in the current frame.
 870                  */
 871                 if (validate_sp(sp, tsk, INT_FRAME_SIZE)
 872                     && stack[FRAME_MARKER] == REGS_MARKER) {
 873                         struct pt_regs *regs = (struct pt_regs *)
 874                                 (sp + STACK_FRAME_OVERHEAD);
 875                         printk("--- Exception: %lx", regs->trap);
 876                         print_symbol(" at %s\n", regs->nip);
 877                         lr = regs->link;
 878                         print_symbol("    LR = %s\n", lr);
 879                         firstframe = 1;
 880                 }
 881
 882                 sp = newsp;
 883         } while (count++ < kstack_depth_to_print);
 884 }
 885
 886 void dump_stack(void)
 887 {
 888         show_stack(current, NULL);
 889 }
 890 EXPORT_SYMBOL(dump_stack);
 891
 892 #ifdef CONFIG_PPC64
 893 void ppc64_runlatch_on(void)
 894 {
 895         unsigned long ctrl;
 896
 897         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
 898                 HMT_medium();
 899
 900                 ctrl = mfspr(SPRN_CTRLF);
 901                 ctrl |= CTRL_RUNLATCH;
 902                 mtspr(SPRN_CTRLT, ctrl);
 903
 904                 set_thread_flag(TIF_RUNLATCH);
 905         }
 906 }
 907
 908 void ppc64_runlatch_off(void)
 909 {
 910         unsigned long ctrl;
 911
 912         if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) {
 913                 HMT_medium();
 914
 915                 clear_thread_flag(TIF_RUNLATCH);
 916
 917                 ctrl = mfspr(SPRN_CTRLF);
 918                 ctrl &= ~CTRL_RUNLATCH;
 919                 mtspr(SPRN_CTRLT, ctrl);
 920         }
 921 }
 922 #endif