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/stddef.h>
  23 #include <linux/unistd.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/slab.h>
  26 #include <linux/user.h>
  27 #include <linux/elf.h>
  28 #include <linux/init.h>
  29 #include <linux/prctl.h>
  30 #include <linux/init_task.h>
  31 #include <linux/module.h>
  32 #include <linux/kallsyms.h>
  33 #include <linux/mqueue.h>
  34 #include <linux/hardirq.h>
  35 #include <linux/utsname.h>
  36
  37 #include <asm/pgtable.h>
  38 #include <asm/uaccess.h>
  39 #include <asm/system.h>
  40 #include <asm/io.h>
  41 #include <asm/processor.h>
  42 #include <asm/mmu.h>
  43 #include <asm/prom.h>
  44 #include <asm/machdep.h>
  45 #include <asm/time.h>
  46 #include <asm/syscalls.h>
  47 #ifdef CONFIG_PPC64
  48 #include <asm/firmware.h>
  49 #endif
  50
  51 extern unsigned long _get_SP(void);
  52
  53 #ifndef CONFIG_SMP
  54 struct task_struct *last_task_used_math = NULL;
  55 struct task_struct *last_task_used_altivec = NULL;
  56 struct task_struct *last_task_used_vsx = 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(tsk);
  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 #ifdef CONFIG_VSX
 111         int i;
 112         elf_fpreg_t *reg;
 113 #endif
 114
 115         if (!tsk->thread.regs)
 116                 return 0;
 117         flush_fp_to_thread(current);
 118
 119 #ifdef CONFIG_VSX
 120         reg = (elf_fpreg_t *)fpregs;
 121         for (i = 0; i < ELF_NFPREG - 1; i++, reg++)
 122                 *reg = tsk->thread.TS_FPR(i);
 123         memcpy(reg, &tsk->thread.fpscr, sizeof(elf_fpreg_t));
 124 #else
 125         memcpy(fpregs, &tsk->thread.TS_FPR(0), sizeof(*fpregs));
 126 #endif
 127
 128         return 1;
 129 }
 130
 131 #ifdef CONFIG_ALTIVEC
 132 void enable_kernel_altivec(void)
 133 {
 134         WARN_ON(preemptible());
 135
 136 #ifdef CONFIG_SMP
 137         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 138                 giveup_altivec(current);
 139         else
 140                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 141 #else
 142         giveup_altivec(last_task_used_altivec);
 143 #endif /* CONFIG_SMP */
 144 }
 145 EXPORT_SYMBOL(enable_kernel_altivec);
 146
 147 /*
 148  * Make sure the VMX/Altivec register state in the
 149  * the thread_struct is up to date for task tsk.
 150  */
 151 void flush_altivec_to_thread(struct task_struct *tsk)
 152 {
 153         if (tsk->thread.regs) {
 154                 preempt_disable();
 155                 if (tsk->thread.regs->msr & MSR_VEC) {
 156 #ifdef CONFIG_SMP
 157                         BUG_ON(tsk != current);
 158 #endif
 159                         giveup_altivec(tsk);
 160                 }
 161                 preempt_enable();
 162         }
 163 }
 164
 165 int dump_task_altivec(struct task_struct *tsk, elf_vrreg_t *vrregs)
 166 {
 167         /* ELF_NVRREG includes the VSCR and VRSAVE which we need to save
 168          * separately, see below */
 169         const int nregs = ELF_NVRREG - 2;
 170         elf_vrreg_t *reg;
 171         u32 *dest;
 172
 173         if (tsk == current)
 174                 flush_altivec_to_thread(tsk);
 175
 176         reg = (elf_vrreg_t *)vrregs;
 177
 178         /* copy the 32 vr registers */
 179         memcpy(reg, &tsk->thread.vr[0], nregs * sizeof(*reg));
 180         reg += nregs;
 181
 182         /* copy the vscr */
 183         memcpy(reg, &tsk->thread.vscr, sizeof(*reg));
 184         reg++;
 185
 186         /* vrsave is stored in the high 32bit slot of the final 128bits */
 187         memset(reg, 0, sizeof(*reg));
 188         dest = (u32 *)reg;
 189         *dest = tsk->thread.vrsave;
 190
 191         return 1;
 192 }
 193 #endif /* CONFIG_ALTIVEC */
 194
 195 #ifdef CONFIG_VSX
 196 #if 0
 197 /* not currently used, but some crazy RAID module might want to later */
 198 void enable_kernel_vsx(void)
 199 {
 200         WARN_ON(preemptible());
 201
 202 #ifdef CONFIG_SMP
 203         if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
 204                 giveup_vsx(current);
 205         else
 206                 giveup_vsx(NULL);       /* just enable vsx for kernel - force */
 207 #else
 208         giveup_vsx(last_task_used_vsx);
 209 #endif /* CONFIG_SMP */
 210 }
 211 EXPORT_SYMBOL(enable_kernel_vsx);
 212 #endif
 213
 214 void flush_vsx_to_thread(struct task_struct *tsk)
 215 {
 216         if (tsk->thread.regs) {
 217                 preempt_disable();
 218                 if (tsk->thread.regs->msr & MSR_VSX) {
 219 #ifdef CONFIG_SMP
 220                         BUG_ON(tsk != current);
 221 #endif
 222                         giveup_vsx(tsk);
 223                 }
 224                 preempt_enable();
 225         }
 226 }
 227
 228 /*
 229  * This dumps the lower half 64bits of the first 32 VSX registers.
 230  * This needs to be called with dump_task_fp and dump_task_altivec to
 231  * get all the VSX state.
 232  */
 233 int dump_task_vsx(struct task_struct *tsk, elf_vrreg_t *vrregs)
 234 {
 235         elf_vrreg_t *reg;
 236         double buf[32];
 237         int i;
 238
 239         if (tsk == current)
 240                 flush_vsx_to_thread(tsk);
 241
 242         reg = (elf_vrreg_t *)vrregs;
 243
 244         for (i = 0; i < 32 ; i++)
 245                 buf[i] = current->thread.fpr[i][TS_VSRLOWOFFSET];
 246         memcpy(reg, buf, sizeof(buf));
 247
 248         return 1;
 249 }
 250 #endif /* CONFIG_VSX */
 251
 252 int dump_task_vector(struct task_struct *tsk, elf_vrregset_t *vrregs)
 253 {
 254         int rc = 0;
 255         elf_vrreg_t *regs = (elf_vrreg_t *)vrregs;
 256 #ifdef CONFIG_ALTIVEC
 257         rc = dump_task_altivec(tsk, regs);
 258         if (rc)
 259                 return rc;
 260         regs += ELF_NVRREG;
 261 #endif
 262
 263 #ifdef CONFIG_VSX
 264         rc = dump_task_vsx(tsk, regs);
 265 #endif
 266         return rc;
 267 }
 268
 269 #ifdef CONFIG_SPE
 270
 271 void enable_kernel_spe(void)
 272 {
 273         WARN_ON(preemptible());
 274
 275 #ifdef CONFIG_SMP
 276         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 277                 giveup_spe(current);
 278         else
 279                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 280 #else
 281         giveup_spe(last_task_used_spe);
 282 #endif /* __SMP __ */
 283 }
 284 EXPORT_SYMBOL(enable_kernel_spe);
 285
 286 void flush_spe_to_thread(struct task_struct *tsk)
 287 {
 288         if (tsk->thread.regs) {
 289                 preempt_disable();
 290                 if (tsk->thread.regs->msr & MSR_SPE) {
 291 #ifdef CONFIG_SMP
 292                         BUG_ON(tsk != current);
 293 #endif
 294                         giveup_spe(tsk);
 295                 }
 296                 preempt_enable();
 297         }
 298 }
 299
 300 int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
 301 {
 302         flush_spe_to_thread(current);
 303         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
 304         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
 305         return 1;
 306 }
 307 #endif /* CONFIG_SPE */
 308
 309 #ifndef CONFIG_SMP
 310 /*
 311  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 312  * and the current task has some state, discard it.
 313  */
 314 void discard_lazy_cpu_state(void)
 315 {
 316         preempt_disable();
 317         if (last_task_used_math == current)
 318                 last_task_used_math = NULL;
 319 #ifdef CONFIG_ALTIVEC
 320         if (last_task_used_altivec == current)
 321                 last_task_used_altivec = NULL;
 322 #endif /* CONFIG_ALTIVEC */
 323 #ifdef CONFIG_VSX
 324         if (last_task_used_vsx == current)
 325                 last_task_used_vsx = NULL;
 326 #endif /* CONFIG_VSX */
 327 #ifdef CONFIG_SPE
 328         if (last_task_used_spe == current)
 329                 last_task_used_spe = NULL;
 330 #endif
 331         preempt_enable();
 332 }
 333 #endif /* CONFIG_SMP */
 334
 335 static DEFINE_PER_CPU(unsigned long, current_dabr);
 336
 337 int set_dabr(unsigned long dabr)
 338 {
 339         __get_cpu_var(current_dabr) = dabr;
 340
 341 #ifdef CONFIG_PPC_MERGE         /* XXX for now */
 342         if (ppc_md.set_dabr)
 343                 return ppc_md.set_dabr(dabr);
 344 #endif
 345
 346         /* XXX should we have a CPU_FTR_HAS_DABR ? */
 347 #if defined(CONFIG_PPC64) || defined(CONFIG_6xx)
 348         mtspr(SPRN_DABR, dabr);
 349 #endif
 350         return 0;
 351 }
 352
 353 #ifdef CONFIG_PPC64
 354 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 355 #endif
 356
 357 struct task_struct *__switch_to(struct task_struct *prev,
 358         struct task_struct *new)
 359 {
 360         struct thread_struct *new_thread, *old_thread;
 361         unsigned long flags;
 362         struct task_struct *last;
 363
 364 #ifdef CONFIG_SMP
 365         /* avoid complexity of lazy save/restore of fpu
 366          * by just saving it every time we switch out if
 367          * this task used the fpu during the last quantum.
 368          *
 369          * If it tries to use the fpu again, it'll trap and
 370          * reload its fp regs.  So we don't have to do a restore
 371          * every switch, just a save.
 372          *  -- Cort
 373          */
 374         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 375                 giveup_fpu(prev);
 376 #ifdef CONFIG_ALTIVEC
 377         /*
 378          * If the previous thread used altivec in the last quantum
 379          * (thus changing altivec regs) then save them.
 380          * We used to check the VRSAVE register but not all apps
 381          * set it, so we don't rely on it now (and in fact we need
 382          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 383          *
 384          * On SMP we always save/restore altivec regs just to avoid the
 385          * complexity of changing processors.
 386          *  -- Cort
 387          */
 388         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 389                 giveup_altivec(prev);
 390 #endif /* CONFIG_ALTIVEC */
 391 #ifdef CONFIG_VSX
 392         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
 393                 giveup_vsx(prev);
 394 #endif /* CONFIG_VSX */
 395 #ifdef CONFIG_SPE
 396         /*
 397          * If the previous thread used spe in the last quantum
 398          * (thus changing spe regs) then save them.
 399          *
 400          * On SMP we always save/restore spe regs just to avoid the
 401          * complexity of changing processors.
 402          */
 403         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 404                 giveup_spe(prev);
 405 #endif /* CONFIG_SPE */
 406
 407 #else  /* CONFIG_SMP */
 408 #ifdef CONFIG_ALTIVEC
 409         /* Avoid the trap.  On smp this this never happens since
 410          * we don't set last_task_used_altivec -- Cort
 411          */
 412         if (new->thread.regs && last_task_used_altivec == new)
 413                 new->thread.regs->msr |= MSR_VEC;
 414 #endif /* CONFIG_ALTIVEC */
 415 #ifdef CONFIG_VSX
 416         if (new->thread.regs && last_task_used_vsx == new)
 417                 new->thread.regs->msr |= MSR_VSX;
 418 #endif /* CONFIG_VSX */
 419 #ifdef CONFIG_SPE
 420         /* Avoid the trap.  On smp this this never happens since
 421          * we don't set last_task_used_spe
 422          */
 423         if (new->thread.regs && last_task_used_spe == new)
 424                 new->thread.regs->msr |= MSR_SPE;
 425 #endif /* CONFIG_SPE */
 426
 427 #endif /* CONFIG_SMP */
 428
 429         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
 430                 set_dabr(new->thread.dabr);
 431
 432         new_thread = &new->thread;
 433         old_thread = &current->thread;
 434
 435 #ifdef CONFIG_PPC64
 436         /*
 437          * Collect processor utilization data per process
 438          */
 439         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 440                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 441                 long unsigned start_tb, current_tb;
 442                 start_tb = old_thread->start_tb;
 443                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 444                 old_thread->accum_tb += (current_tb - start_tb);
 445                 new_thread->start_tb = current_tb;
 446         }
 447 #endif
 448
 449         local_irq_save(flags);
 450
 451         account_system_vtime(current);
 452         account_process_vtime(current);
 453         calculate_steal_time();
 454
 455         /*
 456          * We can't take a PMU exception inside _switch() since there is a
 457          * window where the kernel stack SLB and the kernel stack are out
 458          * of sync. Hard disable here.
 459          */
 460         hard_irq_disable();
 461         last = _switch(old_thread, new_thread);
 462
 463         local_irq_restore(flags);
 464
 465         return last;
 466 }
 467
 468 static int instructions_to_print = 16;
 469
 470 static void show_instructions(struct pt_regs *regs)
 471 {
 472         int i;
 473         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 474                         sizeof(int));
 475
 476         printk("Instruction dump:");
 477
 478         for (i = 0; i < instructions_to_print; i++) {
 479                 int instr;
 480
 481                 if (!(i % 8))
 482                         printk("\n");
 483
 484 #if !defined(CONFIG_BOOKE)
 485                 /* If executing with the IMMU off, adjust pc rather
 486                  * than print XXXXXXXX.
 487                  */
 488                 if (!(regs->msr & MSR_IR))
 489                         pc = (unsigned long)phys_to_virt(pc);
 490 #endif
 491
 492                 /* We use __get_user here *only* to avoid an OOPS on a
 493                  * bad address because the pc *should* only be a
 494                  * kernel address.
 495                  */
 496                 if (!__kernel_text_address(pc) ||
 497                      __get_user(instr, (unsigned int __user *)pc)) {
 498                         printk("XXXXXXXX ");
 499                 } else {
 500                         if (regs->nip == pc)
 501                                 printk("<%08x> ", instr);
 502                         else
 503                                 printk("%08x ", instr);
 504                 }
 505
 506                 pc += sizeof(int);
 507         }
 508
 509         printk("\n");
 510 }
 511
 512 static struct regbit {
 513         unsigned long bit;
 514         const char *name;
 515 } msr_bits[] = {
 516         {MSR_EE,        "EE"},
 517         {MSR_PR,        "PR"},
 518         {MSR_FP,        "FP"},
 519         {MSR_VEC,       "VEC"},
 520         {MSR_VSX,       "VSX"},
 521         {MSR_ME,        "ME"},
 522         {MSR_IR,        "IR"},
 523         {MSR_DR,        "DR"},
 524         {0,             NULL}
 525 };
 526
 527 static void printbits(unsigned long val, struct regbit *bits)
 528 {
 529         const char *sep = "";
 530
 531         printk("<");
 532         for (; bits->bit; ++bits)
 533                 if (val & bits->bit) {
 534                         printk("%s%s", sep, bits->name);
 535                         sep = ",";
 536                 }
 537         printk(">");
 538 }
 539
 540 #ifdef CONFIG_PPC64
 541 #define REG             "%016lx"
 542 #define REGS_PER_LINE   4
 543 #define LAST_VOLATILE   13
 544 #else
 545 #define REG             "%08lx"
 546 #define REGS_PER_LINE   8
 547 #define LAST_VOLATILE   12
 548 #endif
 549
 550 void show_regs(struct pt_regs * regs)
 551 {
 552         int i, trap;
 553
 554         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 555                regs->nip, regs->link, regs->ctr);
 556         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 557                regs, regs->trap, print_tainted(), init_utsname()->release);
 558         printk("MSR: "REG" ", regs->msr);
 559         printbits(regs->msr, msr_bits);
 560         printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
 561         trap = TRAP(regs);
 562         if (trap == 0x300 || trap == 0x600)
 563 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
 564                 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
 565 #else
 566                 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
 567 #endif
 568         printk("TASK = %p[%d] '%s' THREAD: %p",
 569                current, task_pid_nr(current), current->comm, task_thread_info(current));
 570
 571 #ifdef CONFIG_SMP
 572         printk(" CPU: %d", raw_smp_processor_id());
 573 #endif /* CONFIG_SMP */
 574
 575         for (i = 0;  i < 32;  i++) {
 576                 if ((i % REGS_PER_LINE) == 0)
 577                         printk("\n" KERN_INFO "GPR%02d: ", i);
 578                 printk(REG " ", regs->gpr[i]);
 579                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 580                         break;
 581         }
 582         printk("\n");
 583 #ifdef CONFIG_KALLSYMS
 584         /*
 585          * Lookup NIP late so we have the best change of getting the
 586          * above info out without failing
 587          */
 588         printk("NIP ["REG"] ", regs->nip);
 589         print_symbol("%s\n", regs->nip);
 590         printk("LR ["REG"] ", regs->link);
 591         print_symbol("%s\n", regs->link);
 592 #endif
 593         show_stack(current, (unsigned long *) regs->gpr[1]);
 594         if (!user_mode(regs))
 595                 show_instructions(regs);
 596 }
 597
 598 void exit_thread(void)
 599 {
 600         discard_lazy_cpu_state();
 601 }
 602
 603 void flush_thread(void)
 604 {
 605 #ifdef CONFIG_PPC64
 606         struct thread_info *t = current_thread_info();
 607
 608         if (test_ti_thread_flag(t, TIF_ABI_PENDING)) {
 609                 clear_ti_thread_flag(t, TIF_ABI_PENDING);
 610                 if (test_ti_thread_flag(t, TIF_32BIT))
 611                         clear_ti_thread_flag(t, TIF_32BIT);
 612                 else
 613                         set_ti_thread_flag(t, TIF_32BIT);
 614         }
 615 #endif
 616
 617         discard_lazy_cpu_state();
 618
 619         if (current->thread.dabr) {
 620                 current->thread.dabr = 0;
 621                 set_dabr(0);
 622         }
 623 }
 624
 625 void
 626 release_thread(struct task_struct *t)
 627 {
 628 }
 629
 630 /*
 631  * This gets called before we allocate a new thread and copy
 632  * the current task into it.
 633  */
 634 void prepare_to_copy(struct task_struct *tsk)
 635 {
 636         flush_fp_to_thread(current);
 637         flush_altivec_to_thread(current);
 638         flush_vsx_to_thread(current);
 639         flush_spe_to_thread(current);
 640 }
 641
 642 /*
 643  * Copy a thread..
 644  */
 645 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
 646                 unsigned long unused, struct task_struct *p,
 647                 struct pt_regs *regs)
 648 {
 649         struct pt_regs *childregs, *kregs;
 650         extern void ret_from_fork(void);
 651         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 652
 653         CHECK_FULL_REGS(regs);
 654         /* Copy registers */
 655         sp -= sizeof(struct pt_regs);
 656         childregs = (struct pt_regs *) sp;
 657         *childregs = *regs;
 658         if ((childregs->msr & MSR_PR) == 0) {
 659                 /* for kernel thread, set `current' and stackptr in new task */
 660                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 661 #ifdef CONFIG_PPC32
 662                 childregs->gpr[2] = (unsigned long) p;
 663 #else
 664                 clear_tsk_thread_flag(p, TIF_32BIT);
 665 #endif
 666                 p->thread.regs = NULL;  /* no user register state */
 667         } else {
 668                 childregs->gpr[1] = usp;
 669                 p->thread.regs = childregs;
 670                 if (clone_flags & CLONE_SETTLS) {
 671 #ifdef CONFIG_PPC64
 672                         if (!test_thread_flag(TIF_32BIT))
 673                                 childregs->gpr[13] = childregs->gpr[6];
 674                         else
 675 #endif
 676                                 childregs->gpr[2] = childregs->gpr[6];
 677                 }
 678         }
 679         childregs->gpr[3] = 0;  /* Result from fork() */
 680         sp -= STACK_FRAME_OVERHEAD;
 681
 682         /*
 683          * The way this works is that at some point in the future
 684          * some task will call _switch to switch to the new task.
 685          * That will pop off the stack frame created below and start
 686          * the new task running at ret_from_fork.  The new task will
 687          * do some house keeping and then return from the fork or clone
 688          * system call, using the stack frame created above.
 689          */
 690         sp -= sizeof(struct pt_regs);
 691         kregs = (struct pt_regs *) sp;
 692         sp -= STACK_FRAME_OVERHEAD;
 693         p->thread.ksp = sp;
 694         p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
 695                                 _ALIGN_UP(sizeof(struct thread_info), 16);
 696
 697 #ifdef CONFIG_PPC64
 698         if (cpu_has_feature(CPU_FTR_SLB)) {
 699                 unsigned long sp_vsid;
 700                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 701
 702                 if (cpu_has_feature(CPU_FTR_1T_SEGMENT))
 703                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
 704                                 << SLB_VSID_SHIFT_1T;
 705                 else
 706                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
 707                                 << SLB_VSID_SHIFT;
 708                 sp_vsid |= SLB_VSID_KERNEL | llp;
 709                 p->thread.ksp_vsid = sp_vsid;
 710         }
 711
 712         /*
 713          * The PPC64 ABI makes use of a TOC to contain function
 714          * pointers.  The function (ret_from_except) is actually a pointer
 715          * to the TOC entry.  The first entry is a pointer to the actual
 716          * function.
 717          */
 718         kregs->nip = *((unsigned long *)ret_from_fork);
 719 #else
 720         kregs->nip = (unsigned long)ret_from_fork;
 721 #endif
 722
 723         return 0;
 724 }
 725
 726 /*
 727  * Set up a thread for executing a new program
 728  */
 729 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 730 {
 731 #ifdef CONFIG_PPC64
 732         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 733 #endif
 734
 735         set_fs(USER_DS);
 736
 737         /*
 738          * If we exec out of a kernel thread then thread.regs will not be
 739          * set.  Do it now.
 740          */
 741         if (!current->thread.regs) {
 742                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
 743                 current->thread.regs = regs - 1;
 744         }
 745
 746         memset(regs->gpr, 0, sizeof(regs->gpr));
 747         regs->ctr = 0;
 748         regs->link = 0;
 749         regs->xer = 0;
 750         regs->ccr = 0;
 751         regs->gpr[1] = sp;
 752
 753         /*
 754          * We have just cleared all the nonvolatile GPRs, so make
 755          * FULL_REGS(regs) return true.  This is necessary to allow
 756          * ptrace to examine the thread immediately after exec.
 757          */
 758         regs->trap &= ~1UL;
 759
 760 #ifdef CONFIG_PPC32
 761         regs->mq = 0;
 762         regs->nip = start;
 763         regs->msr = MSR_USER;
 764 #else
 765         if (!test_thread_flag(TIF_32BIT)) {
 766                 unsigned long entry, toc;
 767
 768                 /* start is a relocated pointer to the function descriptor for
 769                  * the elf _start routine.  The first entry in the function
 770                  * descriptor is the entry address of _start and the second
 771                  * entry is the TOC value we need to use.
 772                  */
 773                 __get_user(entry, (unsigned long __user *)start);
 774                 __get_user(toc, (unsigned long __user *)start+1);
 775
 776                 /* Check whether the e_entry function descriptor entries
 777                  * need to be relocated before we can use them.
 778                  */
 779                 if (load_addr != 0) {
 780                         entry += load_addr;
 781                         toc   += load_addr;
 782                 }
 783                 regs->nip = entry;
 784                 regs->gpr[2] = toc;
 785                 regs->msr = MSR_USER64;
 786         } else {
 787                 regs->nip = start;
 788                 regs->gpr[2] = 0;
 789                 regs->msr = MSR_USER32;
 790         }
 791 #endif
 792
 793         discard_lazy_cpu_state();
 794 #ifdef CONFIG_VSX
 795         current->thread.used_vsr = 0;
 796 #endif
 797         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 798         current->thread.fpscr.val = 0;
 799 #ifdef CONFIG_ALTIVEC
 800         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 801         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 802         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 803         current->thread.vrsave = 0;
 804         current->thread.used_vr = 0;
 805 #endif /* CONFIG_ALTIVEC */
 806 #ifdef CONFIG_SPE
 807         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 808         current->thread.acc = 0;
 809         current->thread.spefscr = 0;
 810         current->thread.used_spe = 0;
 811 #endif /* CONFIG_SPE */
 812 }
 813
 814 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 815                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 816
 817 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 818 {
 819         struct pt_regs *regs = tsk->thread.regs;
 820
 821         /* This is a bit hairy.  If we are an SPE enabled  processor
 822          * (have embedded fp) we store the IEEE exception enable flags in
 823          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 824          * mode (asyn, precise, disabled) for 'Classic' FP. */
 825         if (val & PR_FP_EXC_SW_ENABLE) {
 826 #ifdef CONFIG_SPE
 827                 if (cpu_has_feature(CPU_FTR_SPE)) {
 828                         tsk->thread.fpexc_mode = val &
 829                                 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 830                         return 0;
 831                 } else {
 832                         return -EINVAL;
 833                 }
 834 #else
 835                 return -EINVAL;
 836 #endif
 837         }
 838
 839         /* on a CONFIG_SPE this does not hurt us.  The bits that
 840          * __pack_fe01 use do not overlap with bits used for
 841          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 842          * on CONFIG_SPE implementations are reserved so writing to
 843          * them does not change anything */
 844         if (val > PR_FP_EXC_PRECISE)
 845                 return -EINVAL;
 846         tsk->thread.fpexc_mode = __pack_fe01(val);
 847         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 848                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 849                         | tsk->thread.fpexc_mode;
 850         return 0;
 851 }
 852
 853 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 854 {
 855         unsigned int val;
 856
 857         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 858 #ifdef CONFIG_SPE
 859                 if (cpu_has_feature(CPU_FTR_SPE))
 860                         val = tsk->thread.fpexc_mode;
 861                 else
 862                         return -EINVAL;
 863 #else
 864                 return -EINVAL;
 865 #endif
 866         else
 867                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 868         return put_user(val, (unsigned int __user *) adr);
 869 }
 870
 871 int set_endian(struct task_struct *tsk, unsigned int val)
 872 {
 873         struct pt_regs *regs = tsk->thread.regs;
 874
 875         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
 876             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
 877                 return -EINVAL;
 878
 879         if (regs == NULL)
 880                 return -EINVAL;
 881
 882         if (val == PR_ENDIAN_BIG)
 883                 regs->msr &= ~MSR_LE;
 884         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
 885                 regs->msr |= MSR_LE;
 886         else
 887                 return -EINVAL;
 888
 889         return 0;
 890 }
 891
 892 int get_endian(struct task_struct *tsk, unsigned long adr)
 893 {
 894         struct pt_regs *regs = tsk->thread.regs;
 895         unsigned int val;
 896
 897         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
 898             !cpu_has_feature(CPU_FTR_REAL_LE))
 899                 return -EINVAL;
 900
 901         if (regs == NULL)
 902                 return -EINVAL;
 903
 904         if (regs->msr & MSR_LE) {
 905                 if (cpu_has_feature(CPU_FTR_REAL_LE))
 906                         val = PR_ENDIAN_LITTLE;
 907                 else
 908                         val = PR_ENDIAN_PPC_LITTLE;
 909         } else
 910                 val = PR_ENDIAN_BIG;
 911
 912         return put_user(val, (unsigned int __user *)adr);
 913 }
 914
 915 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
 916 {
 917         tsk->thread.align_ctl = val;
 918         return 0;
 919 }
 920
 921 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
 922 {
 923         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
 924 }
 925
 926 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
 927
 928 int sys_clone(unsigned long clone_flags, unsigned long usp,
 929               int __user *parent_tidp, void __user *child_threadptr,
 930               int __user *child_tidp, int p6,
 931               struct pt_regs *regs)
 932 {
 933         CHECK_FULL_REGS(regs);
 934         if (usp == 0)
 935                 usp = regs->gpr[1];     /* stack pointer for child */
 936 #ifdef CONFIG_PPC64
 937         if (test_thread_flag(TIF_32BIT)) {
 938                 parent_tidp = TRUNC_PTR(parent_tidp);
 939                 child_tidp = TRUNC_PTR(child_tidp);
 940         }
 941 #endif
 942         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
 943 }
 944
 945 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
 946              unsigned long p4, unsigned long p5, unsigned long p6,
 947              struct pt_regs *regs)
 948 {
 949         CHECK_FULL_REGS(regs);
 950         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
 951 }
 952
 953 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
 954               unsigned long p4, unsigned long p5, unsigned long p6,
 955               struct pt_regs *regs)
 956 {
 957         CHECK_FULL_REGS(regs);
 958         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
 959                         regs, 0, NULL, NULL);
 960 }
 961
 962 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
 963                unsigned long a3, unsigned long a4, unsigned long a5,
 964                struct pt_regs *regs)
 965 {
 966         int error;
 967         char *filename;
 968
 969         filename = getname((char __user *) a0);
 970         error = PTR_ERR(filename);
 971         if (IS_ERR(filename))
 972                 goto out;
 973         flush_fp_to_thread(current);
 974         flush_altivec_to_thread(current);
 975         flush_spe_to_thread(current);
 976         error = do_execve(filename, (char __user * __user *) a1,
 977                           (char __user * __user *) a2, regs);
 978         putname(filename);
 979 out:
 980         return error;
 981 }
 982
 983 #ifdef CONFIG_IRQSTACKS
 984 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
 985                                   unsigned long nbytes)
 986 {
 987         unsigned long stack_page;
 988         unsigned long cpu = task_cpu(p);
 989
 990         /*
 991          * Avoid crashing if the stack has overflowed and corrupted
 992          * task_cpu(p), which is in the thread_info struct.
 993          */
 994         if (cpu < NR_CPUS && cpu_possible(cpu)) {
 995                 stack_page = (unsigned long) hardirq_ctx[cpu];
 996                 if (sp >= stack_page + sizeof(struct thread_struct)
 997                     && sp <= stack_page + THREAD_SIZE - nbytes)
 998                         return 1;
 999
1000                 stack_page = (unsigned long) softirq_ctx[cpu];
1001                 if (sp >= stack_page + sizeof(struct thread_struct)
1002                     && sp <= stack_page + THREAD_SIZE - nbytes)
1003                         return 1;
1004         }
1005         return 0;
1006 }
1007
1008 #else
1009 #define valid_irq_stack(sp, p, nb)      0
1010 #endif /* CONFIG_IRQSTACKS */
1011
1012 int validate_sp(unsigned long sp, struct task_struct *p,
1013                        unsigned long nbytes)
1014 {
1015         unsigned long stack_page = (unsigned long)task_stack_page(p);
1016
1017         if (sp >= stack_page + sizeof(struct thread_struct)
1018             && sp <= stack_page + THREAD_SIZE - nbytes)
1019                 return 1;
1020
1021         return valid_irq_stack(sp, p, nbytes);
1022 }
1023
1024 EXPORT_SYMBOL(validate_sp);
1025
1026 unsigned long get_wchan(struct task_struct *p)
1027 {
1028         unsigned long ip, sp;
1029         int count = 0;
1030
1031         if (!p || p == current || p->state == TASK_RUNNING)
1032                 return 0;
1033
1034         sp = p->thread.ksp;
1035         if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1036                 return 0;
1037
1038         do {
1039                 sp = *(unsigned long *)sp;
1040                 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1041                         return 0;
1042                 if (count > 0) {
1043                         ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1044                         if (!in_sched_functions(ip))
1045                                 return ip;
1046                 }
1047         } while (count++ < 16);
1048         return 0;
1049 }
1050
1051 static int kstack_depth_to_print = 64;
1052
1053 void show_stack(struct task_struct *tsk, unsigned long *stack)
1054 {
1055         unsigned long sp, ip, lr, newsp;
1056         int count = 0;
1057         int firstframe = 1;
1058
1059         sp = (unsigned long) stack;
1060         if (tsk == NULL)
1061                 tsk = current;
1062         if (sp == 0) {
1063                 if (tsk == current)
1064                         asm("mr %0,1" : "=r" (sp));
1065                 else
1066                         sp = tsk->thread.ksp;
1067         }
1068
1069         lr = 0;
1070         printk("Call Trace:\n");
1071         do {
1072                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1073                         return;
1074
1075                 stack = (unsigned long *) sp;
1076                 newsp = stack[0];
1077                 ip = stack[STACK_FRAME_LR_SAVE];
1078                 if (!firstframe || ip != lr) {
1079                         printk("["REG"] ["REG"] ", sp, ip);
1080                         print_symbol("%s", ip);
1081                         if (firstframe)
1082                                 printk(" (unreliable)");
1083                         printk("\n");
1084                 }
1085                 firstframe = 0;
1086
1087                 /*
1088                  * See if this is an exception frame.
1089                  * We look for the "regshere" marker in the current frame.
1090                  */
1091                 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1092                     && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1093                         struct pt_regs *regs = (struct pt_regs *)
1094                                 (sp + STACK_FRAME_OVERHEAD);
1095                         printk("--- Exception: %lx", regs->trap);
1096                         print_symbol(" at %s\n", regs->nip);
1097                         lr = regs->link;
1098                         print_symbol("    LR = %s\n", lr);
1099                         firstframe = 1;
1100                 }
1101
1102                 sp = newsp;
1103         } while (count++ < kstack_depth_to_print);
1104 }
1105
1106 void dump_stack(void)
1107 {
1108         show_stack(current, NULL);
1109 }
1110 EXPORT_SYMBOL(dump_stack);
1111
1112 #ifdef CONFIG_PPC64
1113 void ppc64_runlatch_on(void)
1114 {
1115         unsigned long ctrl;
1116
1117         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
1118                 HMT_medium();
1119
1120                 ctrl = mfspr(SPRN_CTRLF);
1121                 ctrl |= CTRL_RUNLATCH;
1122                 mtspr(SPRN_CTRLT, ctrl);
1123
1124                 set_thread_flag(TIF_RUNLATCH);
1125         }
1126 }
1127
1128 void ppc64_runlatch_off(void)
1129 {
1130         unsigned long ctrl;
1131
1132         if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) {
1133                 HMT_medium();
1134
1135                 clear_thread_flag(TIF_RUNLATCH);
1136
1137                 ctrl = mfspr(SPRN_CTRLF);
1138                 ctrl &= ~CTRL_RUNLATCH;
1139                 mtspr(SPRN_CTRLT, ctrl);
1140         }
1141 }
1142 #endif
1143
1144 #if THREAD_SHIFT < PAGE_SHIFT
1145
1146 static struct kmem_cache *thread_info_cache;
1147
1148 struct thread_info *alloc_thread_info(struct task_struct *tsk)
1149 {
1150         struct thread_info *ti;
1151
1152         ti = kmem_cache_alloc(thread_info_cache, GFP_KERNEL);
1153         if (unlikely(ti == NULL))
1154                 return NULL;
1155 #ifdef CONFIG_DEBUG_STACK_USAGE
1156         memset(ti, 0, THREAD_SIZE);
1157 #endif
1158         return ti;
1159 }
1160
1161 void free_thread_info(struct thread_info *ti)
1162 {
1163         kmem_cache_free(thread_info_cache, ti);
1164 }
1165
1166 void thread_info_cache_init(void)
1167 {
1168         thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
1169                                               THREAD_SIZE, 0, NULL);
1170         BUG_ON(thread_info_cache == NULL);
1171 }
1172
1173 #endif /* THREAD_SHIFT < PAGE_SHIFT */