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/errno.h>
  18 #include <linux/sched.h>
  19 #include <linux/kernel.h>
  20 #include <linux/mm.h>
  21 #include <linux/smp.h>
  22 #include <linux/smp_lock.h>
  23 #include <linux/stddef.h>
  24 #include <linux/unistd.h>
  25 #include <linux/ptrace.h>
  26 #include <linux/slab.h>
  27 #include <linux/user.h>
  28 #include <linux/elf.h>
  29 #include <linux/init.h>
  30 #include <linux/prctl.h>
  31 #include <linux/init_task.h>
  32 #include <linux/module.h>
  33 #include <linux/kallsyms.h>
  34 #include <linux/mqueue.h>
  35 #include <linux/hardirq.h>
  36 #include <linux/utsname.h>
  37
  38 #include <asm/pgtable.h>
  39 #include <asm/uaccess.h>
  40 #include <asm/system.h>
  41 #include <asm/io.h>
  42 #include <asm/processor.h>
  43 #include <asm/mmu.h>
  44 #include <asm/prom.h>
  45 #include <asm/machdep.h>
  46 #include <asm/time.h>
  47 #include <asm/syscalls.h>
  48 #ifdef CONFIG_PPC64
  49 #include <asm/firmware.h>
  50 #endif
  51
  52 extern unsigned long _get_SP(void);
  53
  54 #ifndef CONFIG_SMP
  55 struct task_struct *last_task_used_math = NULL;
  56 struct task_struct *last_task_used_altivec = NULL;
  57 struct task_struct *last_task_used_spe = NULL;
  58 #endif
  59
  60 /*
  61  * Make sure the floating-point register state in the
  62  * the thread_struct is up to date for task tsk.
  63  */
  64 void flush_fp_to_thread(struct task_struct *tsk)
  65 {
  66         if (tsk->thread.regs) {
  67                 /*
  68                  * We need to disable preemption here because if we didn't,
  69                  * another process could get scheduled after the regs->msr
  70                  * test but before we have finished saving the FP registers
  71                  * to the thread_struct.  That process could take over the
  72                  * FPU, and then when we get scheduled again we would store
  73                  * bogus values for the remaining FP registers.
  74                  */
  75                 preempt_disable();
  76                 if (tsk->thread.regs->msr & MSR_FP) {
  77 #ifdef CONFIG_SMP
  78                         /*
  79                          * This should only ever be called for current or
  80                          * for a stopped child process.  Since we save away
  81                          * the FP register state on context switch on SMP,
  82                          * there is something wrong if a stopped child appears
  83                          * to still have its FP state in the CPU registers.
  84                          */
  85                         BUG_ON(tsk != current);
  86 #endif
  87                         giveup_fpu(current);
  88                 }
  89                 preempt_enable();
  90         }
  91 }
  92
  93 void enable_kernel_fp(void)
  94 {
  95         WARN_ON(preemptible());
  96
  97 #ifdef CONFIG_SMP
  98         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
  99                 giveup_fpu(current);
 100         else
 101                 giveup_fpu(NULL);       /* just enables FP for kernel */
 102 #else
 103         giveup_fpu(last_task_used_math);
 104 #endif /* CONFIG_SMP */
 105 }
 106 EXPORT_SYMBOL(enable_kernel_fp);
 107
 108 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
 109 {
 110         if (!tsk->thread.regs)
 111                 return 0;
 112         flush_fp_to_thread(current);
 113
 114         memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
 115
 116         return 1;
 117 }
 118
 119 #ifdef CONFIG_ALTIVEC
 120 void enable_kernel_altivec(void)
 121 {
 122         WARN_ON(preemptible());
 123
 124 #ifdef CONFIG_SMP
 125         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 126                 giveup_altivec(current);
 127         else
 128                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 129 #else
 130         giveup_altivec(last_task_used_altivec);
 131 #endif /* CONFIG_SMP */
 132 }
 133 EXPORT_SYMBOL(enable_kernel_altivec);
 134
 135 /*
 136  * Make sure the VMX/Altivec register state in the
 137  * the thread_struct is up to date for task tsk.
 138  */
 139 void flush_altivec_to_thread(struct task_struct *tsk)
 140 {
 141         if (tsk->thread.regs) {
 142                 preempt_disable();
 143                 if (tsk->thread.regs->msr & MSR_VEC) {
 144 #ifdef CONFIG_SMP
 145                         BUG_ON(tsk != current);
 146 #endif
 147                         giveup_altivec(current);
 148                 }
 149                 preempt_enable();
 150         }
 151 }
 152
 153 int dump_task_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
 154 {
 155         flush_altivec_to_thread(current);
 156         memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
 157         return 1;
 158 }
 159 #endif /* CONFIG_ALTIVEC */
 160
 161 #ifdef CONFIG_SPE
 162
 163 void enable_kernel_spe(void)
 164 {
 165         WARN_ON(preemptible());
 166
 167 #ifdef CONFIG_SMP
 168         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 169                 giveup_spe(current);
 170         else
 171                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 172 #else
 173         giveup_spe(last_task_used_spe);
 174 #endif /* __SMP __ */
 175 }
 176 EXPORT_SYMBOL(enable_kernel_spe);
 177
 178 void flush_spe_to_thread(struct task_struct *tsk)
 179 {
 180         if (tsk->thread.regs) {
 181                 preempt_disable();
 182                 if (tsk->thread.regs->msr & MSR_SPE) {
 183 #ifdef CONFIG_SMP
 184                         BUG_ON(tsk != current);
 185 #endif
 186                         giveup_spe(current);
 187                 }
 188                 preempt_enable();
 189         }
 190 }
 191
 192 int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 193 {
 194         flush_spe_to_thread(current);
 195         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
 196         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
 197         return 1;
 198 }
 199 #endif /* CONFIG_SPE */
 200
 201 #ifndef CONFIG_SMP
 202 /*
 203  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 204  * and the current task has some state, discard it.
 205  */
 206 void discard_lazy_cpu_state(void)
 207 {
 208         preempt_disable();
 209         if (last_task_used_math == current)
 210                 last_task_used_math = NULL;
 211 #ifdef CONFIG_ALTIVEC
 212         if (last_task_used_altivec == current)
 213                 last_task_used_altivec = NULL;
 214 #endif /* CONFIG_ALTIVEC */
 215 #ifdef CONFIG_SPE
 216         if (last_task_used_spe == current)
 217                 last_task_used_spe = NULL;
 218 #endif
 219         preempt_enable();
 220 }
 221 #endif /* CONFIG_SMP */
 222
 223 #ifdef CONFIG_PPC_MERGE         /* XXX for now */
 224 int set_dabr(unsigned long dabr)
 225 {
 226         if (ppc_md.set_dabr)
 227                 return ppc_md.set_dabr(dabr);
 228
 229         mtspr(SPRN_DABR, dabr);
 230         return 0;
 231 }
 232 #endif
 233
 234 #ifdef CONFIG_PPC64
 235 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 236 static DEFINE_PER_CPU(unsigned long, current_dabr);
 237 #endif
 238
 239 struct task_struct *__switch_to(struct task_struct *prev,
 240         struct task_struct *new)
 241 {
 242         struct thread_struct *new_thread, *old_thread;
 243         unsigned long flags;
 244         struct task_struct *last;
 245
 246 #ifdef CONFIG_SMP
 247         /* avoid complexity of lazy save/restore of fpu
 248          * by just saving it every time we switch out if
 249          * this task used the fpu during the last quantum.
 250          *
 251          * If it tries to use the fpu again, it'll trap and
 252          * reload its fp regs.  So we don't have to do a restore
 253          * every switch, just a save.
 254          *  -- Cort
 255          */
 256         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 257                 giveup_fpu(prev);
 258 #ifdef CONFIG_ALTIVEC
 259         /*
 260          * If the previous thread used altivec in the last quantum
 261          * (thus changing altivec regs) then save them.
 262          * We used to check the VRSAVE register but not all apps
 263          * set it, so we don't rely on it now (and in fact we need
 264          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 265          *
 266          * On SMP we always save/restore altivec regs just to avoid the
 267          * complexity of changing processors.
 268          *  -- Cort
 269          */
 270         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 271                 giveup_altivec(prev);
 272 #endif /* CONFIG_ALTIVEC */
 273 #ifdef CONFIG_SPE
 274         /*
 275          * If the previous thread used spe in the last quantum
 276          * (thus changing spe regs) then save them.
 277          *
 278          * On SMP we always save/restore spe regs just to avoid the
 279          * complexity of changing processors.
 280          */
 281         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 282                 giveup_spe(prev);
 283 #endif /* CONFIG_SPE */
 284
 285 #else  /* CONFIG_SMP */
 286 #ifdef CONFIG_ALTIVEC
 287         /* Avoid the trap.  On smp this this never happens since
 288          * we don't set last_task_used_altivec -- Cort
 289          */
 290         if (new->thread.regs && last_task_used_altivec == new)
 291                 new->thread.regs->msr |= MSR_VEC;
 292 #endif /* CONFIG_ALTIVEC */
 293 #ifdef CONFIG_SPE
 294         /* Avoid the trap.  On smp this this never happens since
 295          * we don't set last_task_used_spe
 296          */
 297         if (new->thread.regs && last_task_used_spe == new)
 298                 new->thread.regs->msr |= MSR_SPE;
 299 #endif /* CONFIG_SPE */
 300
 301 #endif /* CONFIG_SMP */
 302
 303 #ifdef CONFIG_PPC64     /* for now */
 304         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
 305                 set_dabr(new->thread.dabr);
 306                 __get_cpu_var(current_dabr) = new->thread.dabr;
 307         }
 308
 309         flush_tlb_pending();
 310 #endif
 311
 312         new_thread = &new->thread;
 313         old_thread = &current->thread;
 314
 315 #ifdef CONFIG_PPC64
 316         /*
 317          * Collect processor utilization data per process
 318          */
 319         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 320                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 321                 long unsigned start_tb, current_tb;
 322                 start_tb = old_thread->start_tb;
 323                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 324                 old_thread->accum_tb += (current_tb - start_tb);
 325                 new_thread->start_tb = current_tb;
 326         }
 327 #endif
 328
 329         local_irq_save(flags);
 330
 331         account_system_vtime(current);
 332         account_process_vtime(current);
 333         calculate_steal_time();
 334
 335         last = _switch(old_thread, new_thread);
 336
 337         local_irq_restore(flags);
 338
 339         return last;
 340 }
 341
 342 static int instructions_to_print = 16;
 343
 344 static void show_instructions(struct pt_regs *regs)
 345 {
 346         int i;
 347         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 348                         sizeof(int));
 349
 350         printk("Instruction dump:");
 351
 352         for (i = 0; i < instructions_to_print; i++) {
 353                 int instr;
 354
 355                 if (!(i % 8))
 356                         printk("\n");
 357
 358                 /* We use __get_user here *only* to avoid an OOPS on a
 359                  * bad address because the pc *should* only be a
 360                  * kernel address.
 361                  */
 362                 if (!__kernel_text_address(pc) ||
 363                      __get_user(instr, (unsigned int __user *)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(), init_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         discard_lazy_cpu_state();
 461 }
 462
 463 void flush_thread(void)
 464 {
 465 #ifdef CONFIG_PPC64
 466         struct thread_info *t = current_thread_info();
 467
 468         if (test_ti_thread_flag(t, TIF_ABI_PENDING)) {
 469                 clear_ti_thread_flag(t, TIF_ABI_PENDING);
 470                 if (test_ti_thread_flag(t, TIF_32BIT))
 471                         clear_ti_thread_flag(t, TIF_32BIT);
 472                 else
 473                         set_ti_thread_flag(t, TIF_32BIT);
 474         }
 475 #endif
 476
 477         discard_lazy_cpu_state();
 478
 479 #ifdef CONFIG_PPC64     /* for now */
 480         if (current->thread.dabr) {
 481                 current->thread.dabr = 0;
 482                 set_dabr(0);
 483         }
 484 #endif
 485 }
 486
 487 void
 488 release_thread(struct task_struct *t)
 489 {
 490 }
 491
 492 /*
 493  * This gets called before we allocate a new thread and copy
 494  * the current task into it.
 495  */
 496 void prepare_to_copy(struct task_struct *tsk)
 497 {
 498         flush_fp_to_thread(current);
 499         flush_altivec_to_thread(current);
 500         flush_spe_to_thread(current);
 501 }
 502
 503 /*
 504  * Copy a thread..
 505  */
 506 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 507                 unsigned long unused, struct task_struct *p,
 508                 struct pt_regs *regs)
 509 {
 510         struct pt_regs *childregs, *kregs;
 511         extern void ret_from_fork(void);
 512         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 513
 514         CHECK_FULL_REGS(regs);
 515         /* Copy registers */
 516         sp -= sizeof(struct pt_regs);
 517         childregs = (struct pt_regs *) sp;
 518         *childregs = *regs;
 519         if ((childregs->msr & MSR_PR) == 0) {
 520                 /* for kernel thread, set `current' and stackptr in new task */
 521                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 522 #ifdef CONFIG_PPC32
 523                 childregs->gpr[2] = (unsigned long) p;
 524 #else
 525                 clear_tsk_thread_flag(p, TIF_32BIT);
 526 #endif
 527                 p->thread.regs = NULL;  /* no user register state */
 528         } else {
 529                 childregs->gpr[1] = usp;
 530                 p->thread.regs = childregs;
 531                 if (clone_flags & CLONE_SETTLS) {
 532 #ifdef CONFIG_PPC64
 533                         if (!test_thread_flag(TIF_32BIT))
 534                                 childregs->gpr[13] = childregs->gpr[6];
 535                         else
 536 #endif
 537                                 childregs->gpr[2] = childregs->gpr[6];
 538                 }
 539         }
 540         childregs->gpr[3] = 0;  /* Result from fork() */
 541         sp -= STACK_FRAME_OVERHEAD;
 542
 543         /*
 544          * The way this works is that at some point in the future
 545          * some task will call _switch to switch to the new task.
 546          * That will pop off the stack frame created below and start
 547          * the new task running at ret_from_fork.  The new task will
 548          * do some house keeping and then return from the fork or clone
 549          * system call, using the stack frame created above.
 550          */
 551         sp -= sizeof(struct pt_regs);
 552         kregs = (struct pt_regs *) sp;
 553         sp -= STACK_FRAME_OVERHEAD;
 554         p->thread.ksp = sp;
 555
 556 #ifdef CONFIG_PPC64
 557         if (cpu_has_feature(CPU_FTR_SLB)) {
 558                 unsigned long sp_vsid = get_kernel_vsid(sp);
 559                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 560
 561                 sp_vsid <<= SLB_VSID_SHIFT;
 562                 sp_vsid |= SLB_VSID_KERNEL | llp;
 563                 p->thread.ksp_vsid = sp_vsid;
 564         }
 565
 566         /*
 567          * The PPC64 ABI makes use of a TOC to contain function
 568          * pointers.  The function (ret_from_except) is actually a pointer
 569          * to the TOC entry.  The first entry is a pointer to the actual
 570          * function.
 571          */
 572         kregs->nip = *((unsigned long *)ret_from_fork);
 573 #else
 574         kregs->nip = (unsigned long)ret_from_fork;
 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 int set_endian(struct task_struct *tsk, unsigned int val)
 709 {
 710         struct pt_regs *regs = tsk->thread.regs;
 711
 712         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
 713             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
 714                 return -EINVAL;
 715
 716         if (regs == NULL)
 717                 return -EINVAL;
 718
 719         if (val == PR_ENDIAN_BIG)
 720                 regs->msr &= ~MSR_LE;
 721         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
 722                 regs->msr |= MSR_LE;
 723         else
 724                 return -EINVAL;
 725
 726         return 0;
 727 }
 728
 729 int get_endian(struct task_struct *tsk, unsigned long adr)
 730 {
 731         struct pt_regs *regs = tsk->thread.regs;
 732         unsigned int val;
 733
 734         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
 735             !cpu_has_feature(CPU_FTR_REAL_LE))
 736                 return -EINVAL;
 737
 738         if (regs == NULL)
 739                 return -EINVAL;
 740
 741         if (regs->msr & MSR_LE) {
 742                 if (cpu_has_feature(CPU_FTR_REAL_LE))
 743                         val = PR_ENDIAN_LITTLE;
 744                 else
 745                         val = PR_ENDIAN_PPC_LITTLE;
 746         } else
 747                 val = PR_ENDIAN_BIG;
 748
 749         return put_user(val, (unsigned int __user *)adr);
 750 }
 751
 752 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
 753 {
 754         tsk->thread.align_ctl = val;
 755         return 0;
 756 }
 757
 758 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
 759 {
 760         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
 761 }
 762
 763 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
 764
 765 int sys_clone(unsigned long clone_flags, unsigned long usp,
 766               int __user *parent_tidp, void __user *child_threadptr,
 767               int __user *child_tidp, int p6,
 768               struct pt_regs *regs)
 769 {
 770         CHECK_FULL_REGS(regs);
 771         if (usp == 0)
 772                 usp = regs->gpr[1];     /* stack pointer for child */
 773 #ifdef CONFIG_PPC64
 774         if (test_thread_flag(TIF_32BIT)) {
 775                 parent_tidp = TRUNC_PTR(parent_tidp);
 776                 child_tidp = TRUNC_PTR(child_tidp);
 777         }
 778 #endif
 779         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 780 }
 781
 782 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 783              unsigned long p4, unsigned long p5, unsigned long p6,
 784              struct pt_regs *regs)
 785 {
 786         CHECK_FULL_REGS(regs);
 787         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 788 }
 789
 790 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 791               unsigned long p4, unsigned long p5, unsigned long p6,
 792               struct pt_regs *regs)
 793 {
 794         CHECK_FULL_REGS(regs);
 795         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 796                         regs, 0, NULL, NULL);
 797 }
 798
 799 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 800                unsigned long a3, unsigned long a4, unsigned long a5,
 801                struct pt_regs *regs)
 802 {
 803         int error;
 804         char *filename;
 805
 806         filename = getname((char __user *) a0);
 807         error = PTR_ERR(filename);
 808         if (IS_ERR(filename))
 809                 goto out;
 810         flush_fp_to_thread(current);
 811         flush_altivec_to_thread(current);
 812         flush_spe_to_thread(current);
 813         error = do_execve(filename, (char __user * __user *) a1,
 814                           (char __user * __user *) a2, regs);
 815         if (error == 0) {
 816                 task_lock(current);
 817                 current->ptrace &= ~PT_DTRACE;
 818                 task_unlock(current);
 819         }
 820         putname(filename);
 821 out:
 822         return error;
 823 }
 824
 825 #ifdef CONFIG_IRQSTACKS
 826 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
 827                                   unsigned long nbytes)
 828 {
 829         unsigned long stack_page;
 830         unsigned long cpu = task_cpu(p);
 831
 832         /*
 833          * Avoid crashing if the stack has overflowed and corrupted
 834          * task_cpu(p), which is in the thread_info struct.
 835          */
 836         if (cpu < NR_CPUS && cpu_possible(cpu)) {
 837                 stack_page = (unsigned long) hardirq_ctx[cpu];
 838                 if (sp >= stack_page + sizeof(struct thread_struct)
 839                     && sp <= stack_page + THREAD_SIZE - nbytes)
 840                         return 1;
 841
 842                 stack_page = (unsigned long) softirq_ctx[cpu];
 843                 if (sp >= stack_page + sizeof(struct thread_struct)
 844                     && sp <= stack_page + THREAD_SIZE - nbytes)
 845                         return 1;
 846         }
 847         return 0;
 848 }
 849
 850 #else
 851 #define valid_irq_stack(sp, p, nb)      0
 852 #endif /* CONFIG_IRQSTACKS */
 853
 854 int validate_sp(unsigned long sp, struct task_struct *p,
 855                        unsigned long nbytes)
 856 {
 857         unsigned long stack_page = (unsigned long)task_stack_page(p);
 858
 859         if (sp >= stack_page + sizeof(struct thread_struct)
 860             && sp <= stack_page + THREAD_SIZE - nbytes)
 861                 return 1;
 862
 863         return valid_irq_stack(sp, p, nbytes);
 864 }
 865
 866 #ifdef CONFIG_PPC64
 867 #define MIN_STACK_FRAME 112     /* same as STACK_FRAME_OVERHEAD, in fact */
 868 #define FRAME_LR_SAVE   2
 869 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
 870 #define REGS_MARKER     0x7265677368657265ul
 871 #define FRAME_MARKER    12
 872 #else
 873 #define MIN_STACK_FRAME 16
 874 #define FRAME_LR_SAVE   1
 875 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
 876 #define REGS_MARKER     0x72656773ul
 877 #define FRAME_MARKER    2
 878 #endif
 879
 880 EXPORT_SYMBOL(validate_sp);
 881
 882 unsigned long get_wchan(struct task_struct *p)
 883 {
 884         unsigned long ip, sp;
 885         int count = 0;
 886
 887         if (!p || p == current || p->state == TASK_RUNNING)
 888                 return 0;
 889
 890         sp = p->thread.ksp;
 891         if (!validate_sp(sp, p, MIN_STACK_FRAME))
 892                 return 0;
 893
 894         do {
 895                 sp = *(unsigned long *)sp;
 896                 if (!validate_sp(sp, p, MIN_STACK_FRAME))
 897                         return 0;
 898                 if (count > 0) {
 899                         ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
 900                         if (!in_sched_functions(ip))
 901                                 return ip;
 902                 }
 903         } while (count++ < 16);
 904         return 0;
 905 }
 906
 907 static int kstack_depth_to_print = 64;
 908
 909 void show_stack(struct task_struct *tsk, unsigned long *stack)
 910 {
 911         unsigned long sp, ip, lr, newsp;
 912         int count = 0;
 913         int firstframe = 1;
 914
 915         sp = (unsigned long) stack;
 916         if (tsk == NULL)
 917                 tsk = current;
 918         if (sp == 0) {
 919                 if (tsk == current)
 920                         asm("mr %0,1" : "=r" (sp));
 921                 else
 922                         sp = tsk->thread.ksp;
 923         }
 924
 925         lr = 0;
 926         printk("Call Trace:\n");
 927         do {
 928                 if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
 929                         return;
 930
 931                 stack = (unsigned long *) sp;
 932                 newsp = stack[0];
 933                 ip = stack[FRAME_LR_SAVE];
 934                 if (!firstframe || ip != lr) {
 935                         printk("["REG"] ["REG"] ", sp, ip);
 936                         print_symbol("%s", ip);
 937                         if (firstframe)
 938                                 printk(" (unreliable)");
 939                         printk("\n");
 940                 }
 941                 firstframe = 0;
 942
 943                 /*
 944                  * See if this is an exception frame.
 945                  * We look for the "regshere" marker in the current frame.
 946                  */
 947                 if (validate_sp(sp, tsk, INT_FRAME_SIZE)
 948                     && stack[FRAME_MARKER] == REGS_MARKER) {
 949                         struct pt_regs *regs = (struct pt_regs *)
 950                                 (sp + STACK_FRAME_OVERHEAD);
 951                         printk("--- Exception: %lx", regs->trap);
 952                         print_symbol(" at %s\n", regs->nip);
 953                         lr = regs->link;
 954                         print_symbol("    LR = %s\n", lr);
 955                         firstframe = 1;
 956                 }
 957
 958                 sp = newsp;
 959         } while (count++ < kstack_depth_to_print);
 960 }
 961
 962 void dump_stack(void)
 963 {
 964         show_stack(current, NULL);
 965 }
 966 EXPORT_SYMBOL(dump_stack);
 967
 968 #ifdef CONFIG_PPC64
 969 void ppc64_runlatch_on(void)
 970 {
 971         unsigned long ctrl;
 972
 973         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
 974                 HMT_medium();
 975
 976                 ctrl = mfspr(SPRN_CTRLF);
 977                 ctrl |= CTRL_RUNLATCH;
 978                 mtspr(SPRN_CTRLT, ctrl);
 979
 980                 set_thread_flag(TIF_RUNLATCH);
 981         }
 982 }
 983
 984 void ppc64_runlatch_off(void)
 985 {
 986         unsigned long ctrl;
 987
 988         if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) {
 989                 HMT_medium();
 990
 991                 clear_thread_flag(TIF_RUNLATCH);
 992
 993                 ctrl = mfspr(SPRN_CTRLF);
 994                 ctrl &= ~CTRL_RUNLATCH;
 995                 mtspr(SPRN_CTRLT, ctrl);
 996         }
 997 }
 998 #endif