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 #include <linux/ftrace.h>
  37 #include <linux/kernel_stat.h>
  38 #include <linux/personality.h>
  39 #include <linux/random.h>
  40 #include <linux/hw_breakpoint.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 #include <asm/time.h>
  51 #include <asm/syscalls.h>
  52 #ifdef CONFIG_PPC64
  53 #include <asm/firmware.h>
  54 #endif
  55 #include <linux/kprobes.h>
  56 #include <linux/kdebug.h>
  57
  58 extern unsigned long _get_SP(void);
  59
  60 #ifndef CONFIG_SMP
  61 struct task_struct *last_task_used_math = NULL;
  62 struct task_struct *last_task_used_altivec = NULL;
  63 struct task_struct *last_task_used_vsx = NULL;
  64 struct task_struct *last_task_used_spe = NULL;
  65 #endif
  66
  67 /*
  68  * Make sure the floating-point register state in the
  69  * the thread_struct is up to date for task tsk.
  70  */
  71 void flush_fp_to_thread(struct task_struct *tsk)
  72 {
  73         if (tsk->thread.regs) {
  74                 /*
  75                  * We need to disable preemption here because if we didn't,
  76                  * another process could get scheduled after the regs->msr
  77                  * test but before we have finished saving the FP registers
  78                  * to the thread_struct.  That process could take over the
  79                  * FPU, and then when we get scheduled again we would store
  80                  * bogus values for the remaining FP registers.
  81                  */
  82                 preempt_disable();
  83                 if (tsk->thread.regs->msr & MSR_FP) {
  84 #ifdef CONFIG_SMP
  85                         /*
  86                          * This should only ever be called for current or
  87                          * for a stopped child process.  Since we save away
  88                          * the FP register state on context switch on SMP,
  89                          * there is something wrong if a stopped child appears
  90                          * to still have its FP state in the CPU registers.
  91                          */
  92                         BUG_ON(tsk != current);
  93 #endif
  94                         giveup_fpu(tsk);
  95                 }
  96                 preempt_enable();
  97         }
  98 }
  99
 100 void enable_kernel_fp(void)
 101 {
 102         WARN_ON(preemptible());
 103
 104 #ifdef CONFIG_SMP
 105         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 106                 giveup_fpu(current);
 107         else
 108                 giveup_fpu(NULL);       /* just enables FP for kernel */
 109 #else
 110         giveup_fpu(last_task_used_math);
 111 #endif /* CONFIG_SMP */
 112 }
 113 EXPORT_SYMBOL(enable_kernel_fp);
 114
 115 #ifdef CONFIG_ALTIVEC
 116 void enable_kernel_altivec(void)
 117 {
 118         WARN_ON(preemptible());
 119
 120 #ifdef CONFIG_SMP
 121         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 122                 giveup_altivec(current);
 123         else
 124                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 125 #else
 126         giveup_altivec(last_task_used_altivec);
 127 #endif /* CONFIG_SMP */
 128 }
 129 EXPORT_SYMBOL(enable_kernel_altivec);
 130
 131 /*
 132  * Make sure the VMX/Altivec register state in the
 133  * the thread_struct is up to date for task tsk.
 134  */
 135 void flush_altivec_to_thread(struct task_struct *tsk)
 136 {
 137         if (tsk->thread.regs) {
 138                 preempt_disable();
 139                 if (tsk->thread.regs->msr & MSR_VEC) {
 140 #ifdef CONFIG_SMP
 141                         BUG_ON(tsk != current);
 142 #endif
 143                         giveup_altivec(tsk);
 144                 }
 145                 preempt_enable();
 146         }
 147 }
 148 #endif /* CONFIG_ALTIVEC */
 149
 150 #ifdef CONFIG_VSX
 151 #if 0
 152 /* not currently used, but some crazy RAID module might want to later */
 153 void enable_kernel_vsx(void)
 154 {
 155         WARN_ON(preemptible());
 156
 157 #ifdef CONFIG_SMP
 158         if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
 159                 giveup_vsx(current);
 160         else
 161                 giveup_vsx(NULL);       /* just enable vsx for kernel - force */
 162 #else
 163         giveup_vsx(last_task_used_vsx);
 164 #endif /* CONFIG_SMP */
 165 }
 166 EXPORT_SYMBOL(enable_kernel_vsx);
 167 #endif
 168
 169 void giveup_vsx(struct task_struct *tsk)
 170 {
 171         giveup_fpu(tsk);
 172         giveup_altivec(tsk);
 173         __giveup_vsx(tsk);
 174 }
 175
 176 void flush_vsx_to_thread(struct task_struct *tsk)
 177 {
 178         if (tsk->thread.regs) {
 179                 preempt_disable();
 180                 if (tsk->thread.regs->msr & MSR_VSX) {
 181 #ifdef CONFIG_SMP
 182                         BUG_ON(tsk != current);
 183 #endif
 184                         giveup_vsx(tsk);
 185                 }
 186                 preempt_enable();
 187         }
 188 }
 189 #endif /* CONFIG_VSX */
 190
 191 #ifdef CONFIG_SPE
 192
 193 void enable_kernel_spe(void)
 194 {
 195         WARN_ON(preemptible());
 196
 197 #ifdef CONFIG_SMP
 198         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 199                 giveup_spe(current);
 200         else
 201                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 202 #else
 203         giveup_spe(last_task_used_spe);
 204 #endif /* __SMP __ */
 205 }
 206 EXPORT_SYMBOL(enable_kernel_spe);
 207
 208 void flush_spe_to_thread(struct task_struct *tsk)
 209 {
 210         if (tsk->thread.regs) {
 211                 preempt_disable();
 212                 if (tsk->thread.regs->msr & MSR_SPE) {
 213 #ifdef CONFIG_SMP
 214                         BUG_ON(tsk != current);
 215 #endif
 216                         giveup_spe(tsk);
 217                 }
 218                 preempt_enable();
 219         }
 220 }
 221 #endif /* CONFIG_SPE */
 222
 223 #ifndef CONFIG_SMP
 224 /*
 225  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 226  * and the current task has some state, discard it.
 227  */
 228 void discard_lazy_cpu_state(void)
 229 {
 230         preempt_disable();
 231         if (last_task_used_math == current)
 232                 last_task_used_math = NULL;
 233 #ifdef CONFIG_ALTIVEC
 234         if (last_task_used_altivec == current)
 235                 last_task_used_altivec = NULL;
 236 #endif /* CONFIG_ALTIVEC */
 237 #ifdef CONFIG_VSX
 238         if (last_task_used_vsx == current)
 239                 last_task_used_vsx = NULL;
 240 #endif /* CONFIG_VSX */
 241 #ifdef CONFIG_SPE
 242         if (last_task_used_spe == current)
 243                 last_task_used_spe = NULL;
 244 #endif
 245         preempt_enable();
 246 }
 247 #endif /* CONFIG_SMP */
 248
 249 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 250 void do_send_trap(struct pt_regs *regs, unsigned long address,
 251                   unsigned long error_code, int signal_code, int breakpt)
 252 {
 253         siginfo_t info;
 254
 255         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 256                         11, SIGSEGV) == NOTIFY_STOP)
 257                 return;
 258
 259         /* Deliver the signal to userspace */
 260         info.si_signo = SIGTRAP;
 261         info.si_errno = breakpt;        /* breakpoint or watchpoint id */
 262         info.si_code = signal_code;
 263         info.si_addr = (void __user *)address;
 264         force_sig_info(SIGTRAP, &info, current);
 265 }
 266 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
 267 void do_dabr(struct pt_regs *regs, unsigned long address,
 268                     unsigned long error_code)
 269 {
 270         siginfo_t info;
 271
 272         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 273                         11, SIGSEGV) == NOTIFY_STOP)
 274                 return;
 275
 276         if (debugger_dabr_match(regs))
 277                 return;
 278
 279         /* Clear the DABR */
 280         set_dabr(0);
 281
 282         /* Deliver the signal to userspace */
 283         info.si_signo = SIGTRAP;
 284         info.si_errno = 0;
 285         info.si_code = TRAP_HWBKPT;
 286         info.si_addr = (void __user *)address;
 287         force_sig_info(SIGTRAP, &info, current);
 288 }
 289 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
 290
 291 static DEFINE_PER_CPU(unsigned long, current_dabr);
 292
 293 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 294 /*
 295  * Set the debug registers back to their default "safe" values.
 296  */
 297 static void set_debug_reg_defaults(struct thread_struct *thread)
 298 {
 299         thread->iac1 = thread->iac2 = 0;
 300 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 301         thread->iac3 = thread->iac4 = 0;
 302 #endif
 303         thread->dac1 = thread->dac2 = 0;
 304 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 305         thread->dvc1 = thread->dvc2 = 0;
 306 #endif
 307         thread->dbcr0 = 0;
 308 #ifdef CONFIG_BOOKE
 309         /*
 310          * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
 311          */
 312         thread->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |   \
 313                         DBCR1_IAC3US | DBCR1_IAC4US;
 314         /*
 315          * Force Data Address Compare User/Supervisor bits to be User-only
 316          * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
 317          */
 318         thread->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
 319 #else
 320         thread->dbcr1 = 0;
 321 #endif
 322 }
 323
 324 static void prime_debug_regs(struct thread_struct *thread)
 325 {
 326         mtspr(SPRN_IAC1, thread->iac1);
 327         mtspr(SPRN_IAC2, thread->iac2);
 328 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 329         mtspr(SPRN_IAC3, thread->iac3);
 330         mtspr(SPRN_IAC4, thread->iac4);
 331 #endif
 332         mtspr(SPRN_DAC1, thread->dac1);
 333         mtspr(SPRN_DAC2, thread->dac2);
 334 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 335         mtspr(SPRN_DVC1, thread->dvc1);
 336         mtspr(SPRN_DVC2, thread->dvc2);
 337 #endif
 338         mtspr(SPRN_DBCR0, thread->dbcr0);
 339         mtspr(SPRN_DBCR1, thread->dbcr1);
 340 #ifdef CONFIG_BOOKE
 341         mtspr(SPRN_DBCR2, thread->dbcr2);
 342 #endif
 343 }
 344 /*
 345  * Unless neither the old or new thread are making use of the
 346  * debug registers, set the debug registers from the values
 347  * stored in the new thread.
 348  */
 349 static void switch_booke_debug_regs(struct thread_struct *new_thread)
 350 {
 351         if ((current->thread.dbcr0 & DBCR0_IDM)
 352                 || (new_thread->dbcr0 & DBCR0_IDM))
 353                         prime_debug_regs(new_thread);
 354 }
 355 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
 356 #ifndef CONFIG_HAVE_HW_BREAKPOINT
 357 static void set_debug_reg_defaults(struct thread_struct *thread)
 358 {
 359         if (thread->dabr) {
 360                 thread->dabr = 0;
 361                 set_dabr(0);
 362         }
 363 }
 364 #endif /* !CONFIG_HAVE_HW_BREAKPOINT */
 365 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
 366
 367 int set_dabr(unsigned long dabr)
 368 {
 369         __get_cpu_var(current_dabr) = dabr;
 370
 371         if (ppc_md.set_dabr)
 372                 return ppc_md.set_dabr(dabr);
 373
 374         /* XXX should we have a CPU_FTR_HAS_DABR ? */
 375 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 376         mtspr(SPRN_DAC1, dabr);
 377 #ifdef CONFIG_PPC_47x
 378         isync();
 379 #endif
 380 #elif defined(CONFIG_PPC_BOOK3S)
 381         mtspr(SPRN_DABR, dabr);
 382 #endif
 383
 384
 385         return 0;
 386 }
 387
 388 #ifdef CONFIG_PPC64
 389 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 390 #endif
 391
 392 struct task_struct *__switch_to(struct task_struct *prev,
 393         struct task_struct *new)
 394 {
 395         struct thread_struct *new_thread, *old_thread;
 396         unsigned long flags;
 397         struct task_struct *last;
 398 #ifdef CONFIG_PPC_BOOK3S_64
 399         struct ppc64_tlb_batch *batch;
 400 #endif
 401
 402 #ifdef CONFIG_SMP
 403         /* avoid complexity of lazy save/restore of fpu
 404          * by just saving it every time we switch out if
 405          * this task used the fpu during the last quantum.
 406          *
 407          * If it tries to use the fpu again, it'll trap and
 408          * reload its fp regs.  So we don't have to do a restore
 409          * every switch, just a save.
 410          *  -- Cort
 411          */
 412         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 413                 giveup_fpu(prev);
 414 #ifdef CONFIG_ALTIVEC
 415         /*
 416          * If the previous thread used altivec in the last quantum
 417          * (thus changing altivec regs) then save them.
 418          * We used to check the VRSAVE register but not all apps
 419          * set it, so we don't rely on it now (and in fact we need
 420          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 421          *
 422          * On SMP we always save/restore altivec regs just to avoid the
 423          * complexity of changing processors.
 424          *  -- Cort
 425          */
 426         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 427                 giveup_altivec(prev);
 428 #endif /* CONFIG_ALTIVEC */
 429 #ifdef CONFIG_VSX
 430         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
 431                 /* VMX and FPU registers are already save here */
 432                 __giveup_vsx(prev);
 433 #endif /* CONFIG_VSX */
 434 #ifdef CONFIG_SPE
 435         /*
 436          * If the previous thread used spe in the last quantum
 437          * (thus changing spe regs) then save them.
 438          *
 439          * On SMP we always save/restore spe regs just to avoid the
 440          * complexity of changing processors.
 441          */
 442         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 443                 giveup_spe(prev);
 444 #endif /* CONFIG_SPE */
 445
 446 #else  /* CONFIG_SMP */
 447 #ifdef CONFIG_ALTIVEC
 448         /* Avoid the trap.  On smp this this never happens since
 449          * we don't set last_task_used_altivec -- Cort
 450          */
 451         if (new->thread.regs && last_task_used_altivec == new)
 452                 new->thread.regs->msr |= MSR_VEC;
 453 #endif /* CONFIG_ALTIVEC */
 454 #ifdef CONFIG_VSX
 455         if (new->thread.regs && last_task_used_vsx == new)
 456                 new->thread.regs->msr |= MSR_VSX;
 457 #endif /* CONFIG_VSX */
 458 #ifdef CONFIG_SPE
 459         /* Avoid the trap.  On smp this this never happens since
 460          * we don't set last_task_used_spe
 461          */
 462         if (new->thread.regs && last_task_used_spe == new)
 463                 new->thread.regs->msr |= MSR_SPE;
 464 #endif /* CONFIG_SPE */
 465
 466 #endif /* CONFIG_SMP */
 467
 468 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 469         switch_booke_debug_regs(&new->thread);
 470 #else
 471 /*
 472  * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
 473  * schedule DABR
 474  */
 475 #ifndef CONFIG_HAVE_HW_BREAKPOINT
 476         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
 477                 set_dabr(new->thread.dabr);
 478 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 479 #endif
 480
 481
 482         new_thread = &new->thread;
 483         old_thread = &current->thread;
 484
 485 #if defined(CONFIG_PPC_BOOK3E_64)
 486         /* XXX Current Book3E code doesn't deal with kernel side DBCR0,
 487          * we always hold the user values, so we set it now.
 488          *
 489          * However, we ensure the kernel MSR:DE is appropriately cleared too
 490          * to avoid spurrious single step exceptions in the kernel.
 491          *
 492          * This will have to change to merge with the ppc32 code at some point,
 493          * but I don't like much what ppc32 is doing today so there's some
 494          * thinking needed there
 495          */
 496         if ((new_thread->dbcr0 | old_thread->dbcr0) & DBCR0_IDM) {
 497                 u32 dbcr0;
 498
 499                 mtmsr(mfmsr() & ~MSR_DE);
 500                 isync();
 501                 dbcr0 = mfspr(SPRN_DBCR0);
 502                 dbcr0 = (dbcr0 & DBCR0_EDM) | new_thread->dbcr0;
 503                 mtspr(SPRN_DBCR0, dbcr0);
 504         }
 505 #endif /* CONFIG_PPC64_BOOK3E */
 506
 507 #ifdef CONFIG_PPC64
 508         /*
 509          * Collect processor utilization data per process
 510          */
 511         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 512                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 513                 long unsigned start_tb, current_tb;
 514                 start_tb = old_thread->start_tb;
 515                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 516                 old_thread->accum_tb += (current_tb - start_tb);
 517                 new_thread->start_tb = current_tb;
 518         }
 519 #endif /* CONFIG_PPC64 */
 520
 521 #ifdef CONFIG_PPC_BOOK3S_64
 522         batch = &__get_cpu_var(ppc64_tlb_batch);
 523         if (batch->active) {
 524                 current_thread_info()->local_flags |= _TLF_LAZY_MMU;
 525                 if (batch->index)
 526                         __flush_tlb_pending(batch);
 527                 batch->active = 0;
 528         }
 529 #endif /* CONFIG_PPC_BOOK3S_64 */
 530
 531         local_irq_save(flags);
 532
 533         account_system_vtime(current);
 534         account_process_vtime(current);
 535
 536         /*
 537          * We can't take a PMU exception inside _switch() since there is a
 538          * window where the kernel stack SLB and the kernel stack are out
 539          * of sync. Hard disable here.
 540          */
 541         hard_irq_disable();
 542         last = _switch(old_thread, new_thread);
 543
 544 #ifdef CONFIG_PPC_BOOK3S_64
 545         if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
 546                 current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
 547                 batch = &__get_cpu_var(ppc64_tlb_batch);
 548                 batch->active = 1;
 549         }
 550 #endif /* CONFIG_PPC_BOOK3S_64 */
 551
 552         local_irq_restore(flags);
 553
 554         return last;
 555 }
 556
 557 static int instructions_to_print = 16;
 558
 559 static void show_instructions(struct pt_regs *regs)
 560 {
 561         int i;
 562         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 563                         sizeof(int));
 564
 565         printk("Instruction dump:");
 566
 567         for (i = 0; i < instructions_to_print; i++) {
 568                 int instr;
 569
 570                 if (!(i % 8))
 571                         printk("\n");
 572
 573 #if !defined(CONFIG_BOOKE)
 574                 /* If executing with the IMMU off, adjust pc rather
 575                  * than print XXXXXXXX.
 576                  */
 577                 if (!(regs->msr & MSR_IR))
 578                         pc = (unsigned long)phys_to_virt(pc);
 579 #endif
 580
 581                 /* We use __get_user here *only* to avoid an OOPS on a
 582                  * bad address because the pc *should* only be a
 583                  * kernel address.
 584                  */
 585                 if (!__kernel_text_address(pc) ||
 586                      __get_user(instr, (unsigned int __user *)pc)) {
 587                         printk("XXXXXXXX ");
 588                 } else {
 589                         if (regs->nip == pc)
 590                                 printk("<%08x> ", instr);
 591                         else
 592                                 printk("%08x ", instr);
 593                 }
 594
 595                 pc += sizeof(int);
 596         }
 597
 598         printk("\n");
 599 }
 600
 601 static struct regbit {
 602         unsigned long bit;
 603         const char *name;
 604 } msr_bits[] = {
 605         {MSR_EE,        "EE"},
 606         {MSR_PR,        "PR"},
 607         {MSR_FP,        "FP"},
 608         {MSR_VEC,       "VEC"},
 609         {MSR_VSX,       "VSX"},
 610         {MSR_ME,        "ME"},
 611         {MSR_CE,        "CE"},
 612         {MSR_DE,        "DE"},
 613         {MSR_IR,        "IR"},
 614         {MSR_DR,        "DR"},
 615         {0,             NULL}
 616 };
 617
 618 static void printbits(unsigned long val, struct regbit *bits)
 619 {
 620         const char *sep = "";
 621
 622         printk("<");
 623         for (; bits->bit; ++bits)
 624                 if (val & bits->bit) {
 625                         printk("%s%s", sep, bits->name);
 626                         sep = ",";
 627                 }
 628         printk(">");
 629 }
 630
 631 #ifdef CONFIG_PPC64
 632 #define REG             "%016lx"
 633 #define REGS_PER_LINE   4
 634 #define LAST_VOLATILE   13
 635 #else
 636 #define REG             "%08lx"
 637 #define REGS_PER_LINE   8
 638 #define LAST_VOLATILE   12
 639 #endif
 640
 641 void show_regs(struct pt_regs * regs)
 642 {
 643         int i, trap;
 644
 645         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 646                regs->nip, regs->link, regs->ctr);
 647         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 648                regs, regs->trap, print_tainted(), init_utsname()->release);
 649         printk("MSR: "REG" ", regs->msr);
 650         printbits(regs->msr, msr_bits);
 651         printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
 652         trap = TRAP(regs);
 653         if (trap == 0x300 || trap == 0x600)
 654 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 655                 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
 656 #else
 657                 printk("DAR: "REG", DSISR: %08lx\n", regs->dar, regs->dsisr);
 658 #endif
 659         printk("TASK = %p[%d] '%s' THREAD: %p",
 660                current, task_pid_nr(current), current->comm, task_thread_info(current));
 661
 662 #ifdef CONFIG_SMP
 663         printk(" CPU: %d", raw_smp_processor_id());
 664 #endif /* CONFIG_SMP */
 665
 666         for (i = 0;  i < 32;  i++) {
 667                 if ((i % REGS_PER_LINE) == 0)
 668                         printk("\nGPR%02d: ", i);
 669                 printk(REG " ", regs->gpr[i]);
 670                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 671                         break;
 672         }
 673         printk("\n");
 674 #ifdef CONFIG_KALLSYMS
 675         /*
 676          * Lookup NIP late so we have the best change of getting the
 677          * above info out without failing
 678          */
 679         printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
 680         printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
 681 #endif
 682         show_stack(current, (unsigned long *) regs->gpr[1]);
 683         if (!user_mode(regs))
 684                 show_instructions(regs);
 685 }
 686
 687 void exit_thread(void)
 688 {
 689         discard_lazy_cpu_state();
 690 }
 691
 692 void flush_thread(void)
 693 {
 694         discard_lazy_cpu_state();
 695
 696 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 697         flush_ptrace_hw_breakpoint(current);
 698 #else /* CONFIG_HAVE_HW_BREAKPOINT */
 699         set_debug_reg_defaults(&current->thread);
 700 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 701 }
 702
 703 void
 704 release_thread(struct task_struct *t)
 705 {
 706 }
 707
 708 /*
 709  * This gets called before we allocate a new thread and copy
 710  * the current task into it.
 711  */
 712 void prepare_to_copy(struct task_struct *tsk)
 713 {
 714         flush_fp_to_thread(current);
 715         flush_altivec_to_thread(current);
 716         flush_vsx_to_thread(current);
 717         flush_spe_to_thread(current);
 718 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 719         flush_ptrace_hw_breakpoint(tsk);
 720 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 721 }
 722
 723 /*
 724  * Copy a thread..
 725  */
 726 extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
 727
 728 int copy_thread(unsigned long clone_flags, unsigned long usp,
 729                 unsigned long unused, struct task_struct *p,
 730                 struct pt_regs *regs)
 731 {
 732         struct pt_regs *childregs, *kregs;
 733         extern void ret_from_fork(void);
 734         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 735
 736         CHECK_FULL_REGS(regs);
 737         /* Copy registers */
 738         sp -= sizeof(struct pt_regs);
 739         childregs = (struct pt_regs *) sp;
 740         *childregs = *regs;
 741         if ((childregs->msr & MSR_PR) == 0) {
 742                 /* for kernel thread, set `current' and stackptr in new task */
 743                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 744 #ifdef CONFIG_PPC32
 745                 childregs->gpr[2] = (unsigned long) p;
 746 #else
 747                 clear_tsk_thread_flag(p, TIF_32BIT);
 748 #endif
 749                 p->thread.regs = NULL;  /* no user register state */
 750         } else {
 751                 childregs->gpr[1] = usp;
 752                 p->thread.regs = childregs;
 753                 if (clone_flags & CLONE_SETTLS) {
 754 #ifdef CONFIG_PPC64
 755                         if (!is_32bit_task())
 756                                 childregs->gpr[13] = childregs->gpr[6];
 757                         else
 758 #endif
 759                                 childregs->gpr[2] = childregs->gpr[6];
 760                 }
 761         }
 762         childregs->gpr[3] = 0;  /* Result from fork() */
 763         sp -= STACK_FRAME_OVERHEAD;
 764
 765         /*
 766          * The way this works is that at some point in the future
 767          * some task will call _switch to switch to the new task.
 768          * That will pop off the stack frame created below and start
 769          * the new task running at ret_from_fork.  The new task will
 770          * do some house keeping and then return from the fork or clone
 771          * system call, using the stack frame created above.
 772          */
 773         sp -= sizeof(struct pt_regs);
 774         kregs = (struct pt_regs *) sp;
 775         sp -= STACK_FRAME_OVERHEAD;
 776         p->thread.ksp = sp;
 777         p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
 778                                 _ALIGN_UP(sizeof(struct thread_info), 16);
 779
 780 #ifdef CONFIG_PPC_STD_MMU_64
 781         if (mmu_has_feature(MMU_FTR_SLB)) {
 782                 unsigned long sp_vsid;
 783                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 784
 785                 if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
 786                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
 787                                 << SLB_VSID_SHIFT_1T;
 788                 else
 789                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
 790                                 << SLB_VSID_SHIFT;
 791                 sp_vsid |= SLB_VSID_KERNEL | llp;
 792                 p->thread.ksp_vsid = sp_vsid;
 793         }
 794 #endif /* CONFIG_PPC_STD_MMU_64 */
 795 #ifdef CONFIG_PPC64
 796         if (cpu_has_feature(CPU_FTR_DSCR)) {
 797                 if (current->thread.dscr_inherit) {
 798                         p->thread.dscr_inherit = 1;
 799                         p->thread.dscr = current->thread.dscr;
 800                 } else if (0 != dscr_default) {
 801                         p->thread.dscr_inherit = 1;
 802                         p->thread.dscr = dscr_default;
 803                 } else {
 804                         p->thread.dscr_inherit = 0;
 805                         p->thread.dscr = 0;
 806                 }
 807         }
 808 #endif
 809
 810         /*
 811          * The PPC64 ABI makes use of a TOC to contain function
 812          * pointers.  The function (ret_from_except) is actually a pointer
 813          * to the TOC entry.  The first entry is a pointer to the actual
 814          * function.
 815          */
 816 #ifdef CONFIG_PPC64
 817         kregs->nip = *((unsigned long *)ret_from_fork);
 818 #else
 819         kregs->nip = (unsigned long)ret_from_fork;
 820 #endif
 821
 822         return 0;
 823 }
 824
 825 /*
 826  * Set up a thread for executing a new program
 827  */
 828 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 829 {
 830 #ifdef CONFIG_PPC64
 831         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 832 #endif
 833
 834         /*
 835          * If we exec out of a kernel thread then thread.regs will not be
 836          * set.  Do it now.
 837          */
 838         if (!current->thread.regs) {
 839                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
 840                 current->thread.regs = regs - 1;
 841         }
 842
 843         memset(regs->gpr, 0, sizeof(regs->gpr));
 844         regs->ctr = 0;
 845         regs->link = 0;
 846         regs->xer = 0;
 847         regs->ccr = 0;
 848         regs->gpr[1] = sp;
 849
 850         /*
 851          * We have just cleared all the nonvolatile GPRs, so make
 852          * FULL_REGS(regs) return true.  This is necessary to allow
 853          * ptrace to examine the thread immediately after exec.
 854          */
 855         regs->trap &= ~1UL;
 856
 857 #ifdef CONFIG_PPC32
 858         regs->mq = 0;
 859         regs->nip = start;
 860         regs->msr = MSR_USER;
 861 #else
 862         if (!is_32bit_task()) {
 863                 unsigned long entry, toc;
 864
 865                 /* start is a relocated pointer to the function descriptor for
 866                  * the elf _start routine.  The first entry in the function
 867                  * descriptor is the entry address of _start and the second
 868                  * entry is the TOC value we need to use.
 869                  */
 870                 __get_user(entry, (unsigned long __user *)start);
 871                 __get_user(toc, (unsigned long __user *)start+1);
 872
 873                 /* Check whether the e_entry function descriptor entries
 874                  * need to be relocated before we can use them.
 875                  */
 876                 if (load_addr != 0) {
 877                         entry += load_addr;
 878                         toc   += load_addr;
 879                 }
 880                 regs->nip = entry;
 881                 regs->gpr[2] = toc;
 882                 regs->msr = MSR_USER64;
 883         } else {
 884                 regs->nip = start;
 885                 regs->gpr[2] = 0;
 886                 regs->msr = MSR_USER32;
 887         }
 888 #endif
 889
 890         discard_lazy_cpu_state();
 891 #ifdef CONFIG_VSX
 892         current->thread.used_vsr = 0;
 893 #endif
 894         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 895         current->thread.fpscr.val = 0;
 896 #ifdef CONFIG_ALTIVEC
 897         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 898         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 899         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 900         current->thread.vrsave = 0;
 901         current->thread.used_vr = 0;
 902 #endif /* CONFIG_ALTIVEC */
 903 #ifdef CONFIG_SPE
 904         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 905         current->thread.acc = 0;
 906         current->thread.spefscr = 0;
 907         current->thread.used_spe = 0;
 908 #endif /* CONFIG_SPE */
 909 }
 910
 911 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 912                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 913
 914 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 915 {
 916         struct pt_regs *regs = tsk->thread.regs;
 917
 918         /* This is a bit hairy.  If we are an SPE enabled  processor
 919          * (have embedded fp) we store the IEEE exception enable flags in
 920          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 921          * mode (asyn, precise, disabled) for 'Classic' FP. */
 922         if (val & PR_FP_EXC_SW_ENABLE) {
 923 #ifdef CONFIG_SPE
 924                 if (cpu_has_feature(CPU_FTR_SPE)) {
 925                         tsk->thread.fpexc_mode = val &
 926                                 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 927                         return 0;
 928                 } else {
 929                         return -EINVAL;
 930                 }
 931 #else
 932                 return -EINVAL;
 933 #endif
 934         }
 935
 936         /* on a CONFIG_SPE this does not hurt us.  The bits that
 937          * __pack_fe01 use do not overlap with bits used for
 938          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 939          * on CONFIG_SPE implementations are reserved so writing to
 940          * them does not change anything */
 941         if (val > PR_FP_EXC_PRECISE)
 942                 return -EINVAL;
 943         tsk->thread.fpexc_mode = __pack_fe01(val);
 944         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 945                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 946                         | tsk->thread.fpexc_mode;
 947         return 0;
 948 }
 949
 950 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 951 {
 952         unsigned int val;
 953
 954         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 955 #ifdef CONFIG_SPE
 956                 if (cpu_has_feature(CPU_FTR_SPE))
 957                         val = tsk->thread.fpexc_mode;
 958                 else
 959                         return -EINVAL;
 960 #else
 961                 return -EINVAL;
 962 #endif
 963         else
 964                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 965         return put_user(val, (unsigned int __user *) adr);
 966 }
 967
 968 int set_endian(struct task_struct *tsk, unsigned int val)
 969 {
 970         struct pt_regs *regs = tsk->thread.regs;
 971
 972         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
 973             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
 974                 return -EINVAL;
 975
 976         if (regs == NULL)
 977                 return -EINVAL;
 978
 979         if (val == PR_ENDIAN_BIG)
 980                 regs->msr &= ~MSR_LE;
 981         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
 982                 regs->msr |= MSR_LE;
 983         else
 984                 return -EINVAL;
 985
 986         return 0;
 987 }
 988
 989 int get_endian(struct task_struct *tsk, unsigned long adr)
 990 {
 991         struct pt_regs *regs = tsk->thread.regs;
 992         unsigned int val;
 993
 994         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
 995             !cpu_has_feature(CPU_FTR_REAL_LE))
 996                 return -EINVAL;
 997
 998         if (regs == NULL)
 999                 return -EINVAL;
1000
1001         if (regs->msr & MSR_LE) {
1002                 if (cpu_has_feature(CPU_FTR_REAL_LE))
1003                         val = PR_ENDIAN_LITTLE;
1004                 else
1005                         val = PR_ENDIAN_PPC_LITTLE;
1006         } else
1007                 val = PR_ENDIAN_BIG;
1008
1009         return put_user(val, (unsigned int __user *)adr);
1010 }
1011
1012 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
1013 {
1014         tsk->thread.align_ctl = val;
1015         return 0;
1016 }
1017
1018 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
1019 {
1020         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
1021 }
1022
1023 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
1024
1025 int sys_clone(unsigned long clone_flags, unsigned long usp,
1026               int __user *parent_tidp, void __user *child_threadptr,
1027               int __user *child_tidp, int p6,
1028               struct pt_regs *regs)
1029 {
1030         CHECK_FULL_REGS(regs);
1031         if (usp == 0)
1032                 usp = regs->gpr[1];     /* stack pointer for child */
1033 #ifdef CONFIG_PPC64
1034         if (is_32bit_task()) {
1035                 parent_tidp = TRUNC_PTR(parent_tidp);
1036                 child_tidp = TRUNC_PTR(child_tidp);
1037         }
1038 #endif
1039         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
1040 }
1041
1042 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
1043              unsigned long p4, unsigned long p5, unsigned long p6,
1044              struct pt_regs *regs)
1045 {
1046         CHECK_FULL_REGS(regs);
1047         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
1048 }
1049
1050 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
1051               unsigned long p4, unsigned long p5, unsigned long p6,
1052               struct pt_regs *regs)
1053 {
1054         CHECK_FULL_REGS(regs);
1055         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
1056                         regs, 0, NULL, NULL);
1057 }
1058
1059 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
1060                unsigned long a3, unsigned long a4, unsigned long a5,
1061                struct pt_regs *regs)
1062 {
1063         int error;
1064         char *filename;
1065
1066         filename = getname((const char __user *) a0);
1067         error = PTR_ERR(filename);
1068         if (IS_ERR(filename))
1069                 goto out;
1070         flush_fp_to_thread(current);
1071         flush_altivec_to_thread(current);
1072         flush_spe_to_thread(current);
1073         error = do_execve(filename,
1074                           (const char __user *const __user *) a1,
1075                           (const char __user *const __user *) a2, regs);
1076         putname(filename);
1077 out:
1078         return error;
1079 }
1080
1081 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
1082                                   unsigned long nbytes)
1083 {
1084         unsigned long stack_page;
1085         unsigned long cpu = task_cpu(p);
1086
1087         /*
1088          * Avoid crashing if the stack has overflowed and corrupted
1089          * task_cpu(p), which is in the thread_info struct.
1090          */
1091         if (cpu < NR_CPUS && cpu_possible(cpu)) {
1092                 stack_page = (unsigned long) hardirq_ctx[cpu];
1093                 if (sp >= stack_page + sizeof(struct thread_struct)
1094                     && sp <= stack_page + THREAD_SIZE - nbytes)
1095                         return 1;
1096
1097                 stack_page = (unsigned long) softirq_ctx[cpu];
1098                 if (sp >= stack_page + sizeof(struct thread_struct)
1099                     && sp <= stack_page + THREAD_SIZE - nbytes)
1100                         return 1;
1101         }
1102         return 0;
1103 }
1104
1105 int validate_sp(unsigned long sp, struct task_struct *p,
1106                        unsigned long nbytes)
1107 {
1108         unsigned long stack_page = (unsigned long)task_stack_page(p);
1109
1110         if (sp >= stack_page + sizeof(struct thread_struct)
1111             && sp <= stack_page + THREAD_SIZE - nbytes)
1112                 return 1;
1113
1114         return valid_irq_stack(sp, p, nbytes);
1115 }
1116
1117 EXPORT_SYMBOL(validate_sp);
1118
1119 unsigned long get_wchan(struct task_struct *p)
1120 {
1121         unsigned long ip, sp;
1122         int count = 0;
1123
1124         if (!p || p == current || p->state == TASK_RUNNING)
1125                 return 0;
1126
1127         sp = p->thread.ksp;
1128         if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1129                 return 0;
1130
1131         do {
1132                 sp = *(unsigned long *)sp;
1133                 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1134                         return 0;
1135                 if (count > 0) {
1136                         ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1137                         if (!in_sched_functions(ip))
1138                                 return ip;
1139                 }
1140         } while (count++ < 16);
1141         return 0;
1142 }
1143
1144 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1145
1146 void show_stack(struct task_struct *tsk, unsigned long *stack)
1147 {
1148         unsigned long sp, ip, lr, newsp;
1149         int count = 0;
1150         int firstframe = 1;
1151 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1152         int curr_frame = current->curr_ret_stack;
1153         extern void return_to_handler(void);
1154         unsigned long rth = (unsigned long)return_to_handler;
1155         unsigned long mrth = -1;
1156 #ifdef CONFIG_PPC64
1157         extern void mod_return_to_handler(void);
1158         rth = *(unsigned long *)rth;
1159         mrth = (unsigned long)mod_return_to_handler;
1160         mrth = *(unsigned long *)mrth;
1161 #endif
1162 #endif
1163
1164         sp = (unsigned long) stack;
1165         if (tsk == NULL)
1166                 tsk = current;
1167         if (sp == 0) {
1168                 if (tsk == current)
1169                         asm("mr %0,1" : "=r" (sp));
1170                 else
1171                         sp = tsk->thread.ksp;
1172         }
1173
1174         lr = 0;
1175         printk("Call Trace:\n");
1176         do {
1177                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1178                         return;
1179
1180                 stack = (unsigned long *) sp;
1181                 newsp = stack[0];
1182                 ip = stack[STACK_FRAME_LR_SAVE];
1183                 if (!firstframe || ip != lr) {
1184                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1185 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1186                         if ((ip == rth || ip == mrth) && curr_frame >= 0) {
1187                                 printk(" (%pS)",
1188                                        (void *)current->ret_stack[curr_frame].ret);
1189                                 curr_frame--;
1190                         }
1191 #endif
1192                         if (firstframe)
1193                                 printk(" (unreliable)");
1194                         printk("\n");
1195                 }
1196                 firstframe = 0;
1197
1198                 /*
1199                  * See if this is an exception frame.
1200                  * We look for the "regshere" marker in the current frame.
1201                  */
1202                 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1203                     && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1204                         struct pt_regs *regs = (struct pt_regs *)
1205                                 (sp + STACK_FRAME_OVERHEAD);
1206                         lr = regs->link;
1207                         printk("--- Exception: %lx at %pS\n    LR = %pS\n",
1208                                regs->trap, (void *)regs->nip, (void *)lr);
1209                         firstframe = 1;
1210                 }
1211
1212                 sp = newsp;
1213         } while (count++ < kstack_depth_to_print);
1214 }
1215
1216 void dump_stack(void)
1217 {
1218         show_stack(current, NULL);
1219 }
1220 EXPORT_SYMBOL(dump_stack);
1221
1222 #ifdef CONFIG_PPC64
1223 void ppc64_runlatch_on(void)
1224 {
1225         unsigned long ctrl;
1226
1227         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
1228                 HMT_medium();
1229
1230                 ctrl = mfspr(SPRN_CTRLF);
1231                 ctrl |= CTRL_RUNLATCH;
1232                 mtspr(SPRN_CTRLT, ctrl);
1233
1234                 set_thread_flag(TIF_RUNLATCH);
1235         }
1236 }
1237
1238 void __ppc64_runlatch_off(void)
1239 {
1240         unsigned long ctrl;
1241
1242         HMT_medium();
1243
1244         clear_thread_flag(TIF_RUNLATCH);
1245
1246         ctrl = mfspr(SPRN_CTRLF);
1247         ctrl &= ~CTRL_RUNLATCH;
1248         mtspr(SPRN_CTRLT, ctrl);
1249 }
1250 #endif
1251
1252 #if THREAD_SHIFT < PAGE_SHIFT
1253
1254 static struct kmem_cache *thread_info_cache;
1255
1256 struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
1257 {
1258         struct thread_info *ti;
1259
1260         ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
1261         if (unlikely(ti == NULL))
1262                 return NULL;
1263 #ifdef CONFIG_DEBUG_STACK_USAGE
1264         memset(ti, 0, THREAD_SIZE);
1265 #endif
1266         return ti;
1267 }
1268
1269 void free_thread_info(struct thread_info *ti)
1270 {
1271         kmem_cache_free(thread_info_cache, ti);
1272 }
1273
1274 void thread_info_cache_init(void)
1275 {
1276         thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
1277                                               THREAD_SIZE, 0, NULL);
1278         BUG_ON(thread_info_cache == NULL);
1279 }
1280
1281 #endif /* THREAD_SHIFT < PAGE_SHIFT */
1282
1283 unsigned long arch_align_stack(unsigned long sp)
1284 {
1285         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
1286                 sp -= get_random_int() & ~PAGE_MASK;
1287         return sp & ~0xf;
1288 }
1289
1290 static inline unsigned long brk_rnd(void)
1291 {
1292         unsigned long rnd = 0;
1293
1294         /* 8MB for 32bit, 1GB for 64bit */
1295         if (is_32bit_task())
1296                 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
1297         else
1298                 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
1299
1300         return rnd << PAGE_SHIFT;
1301 }
1302
1303 unsigned long arch_randomize_brk(struct mm_struct *mm)
1304 {
1305         unsigned long base = mm->brk;
1306         unsigned long ret;
1307
1308 #ifdef CONFIG_PPC_STD_MMU_64
1309         /*
1310          * If we are using 1TB segments and we are allowed to randomise
1311          * the heap, we can put it above 1TB so it is backed by a 1TB
1312          * segment. Otherwise the heap will be in the bottom 1TB
1313          * which always uses 256MB segments and this may result in a
1314          * performance penalty.
1315          */
1316         if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
1317                 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
1318 #endif
1319
1320         ret = PAGE_ALIGN(base + brk_rnd());
1321
1322         if (ret < mm->brk)
1323                 return mm->brk;
1324
1325         return ret;
1326 }
1327
1328 unsigned long randomize_et_dyn(unsigned long base)
1329 {
1330         unsigned long ret = PAGE_ALIGN(base + brk_rnd());
1331
1332         if (ret < base)
1333                 return base;
1334
1335         return ret;
1336 }