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/export.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/io.h>
  45 #include <asm/processor.h>
  46 #include <asm/mmu.h>
  47 #include <asm/prom.h>
  48 #include <asm/machdep.h>
  49 #include <asm/time.h>
  50 #include <asm/runlatch.h>
  51 #include <asm/syscalls.h>
  52 #include <asm/switch_to.h>
  53 #include <asm/debug.h>
  54 #ifdef CONFIG_PPC64
  55 #include <asm/firmware.h>
  56 #endif
  57 #include <linux/kprobes.h>
  58 #include <linux/kdebug.h>
  59
  60 extern unsigned long _get_SP(void);
  61
  62 #ifndef CONFIG_SMP
  63 struct task_struct *last_task_used_math = NULL;
  64 struct task_struct *last_task_used_altivec = NULL;
  65 struct task_struct *last_task_used_vsx = NULL;
  66 struct task_struct *last_task_used_spe = NULL;
  67 #endif
  68
  69 /*
  70  * Make sure the floating-point register state in the
  71  * the thread_struct is up to date for task tsk.
  72  */
  73 void flush_fp_to_thread(struct task_struct *tsk)
  74 {
  75         if (tsk->thread.regs) {
  76                 /*
  77                  * We need to disable preemption here because if we didn't,
  78                  * another process could get scheduled after the regs->msr
  79                  * test but before we have finished saving the FP registers
  80                  * to the thread_struct.  That process could take over the
  81                  * FPU, and then when we get scheduled again we would store
  82                  * bogus values for the remaining FP registers.
  83                  */
  84                 preempt_disable();
  85                 if (tsk->thread.regs->msr & MSR_FP) {
  86 #ifdef CONFIG_SMP
  87                         /*
  88                          * This should only ever be called for current or
  89                          * for a stopped child process.  Since we save away
  90                          * the FP register state on context switch on SMP,
  91                          * there is something wrong if a stopped child appears
  92                          * to still have its FP state in the CPU registers.
  93                          */
  94                         BUG_ON(tsk != current);
  95 #endif
  96                         giveup_fpu(tsk);
  97                 }
  98                 preempt_enable();
  99         }
 100 }
 101 EXPORT_SYMBOL_GPL(flush_fp_to_thread);
 102
 103 void enable_kernel_fp(void)
 104 {
 105         WARN_ON(preemptible());
 106
 107 #ifdef CONFIG_SMP
 108         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 109                 giveup_fpu(current);
 110         else
 111                 giveup_fpu(NULL);       /* just enables FP for kernel */
 112 #else
 113         giveup_fpu(last_task_used_math);
 114 #endif /* CONFIG_SMP */
 115 }
 116 EXPORT_SYMBOL(enable_kernel_fp);
 117
 118 #ifdef CONFIG_ALTIVEC
 119 void enable_kernel_altivec(void)
 120 {
 121         WARN_ON(preemptible());
 122
 123 #ifdef CONFIG_SMP
 124         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 125                 giveup_altivec(current);
 126         else
 127                 giveup_altivec_notask();
 128 #else
 129         giveup_altivec(last_task_used_altivec);
 130 #endif /* CONFIG_SMP */
 131 }
 132 EXPORT_SYMBOL(enable_kernel_altivec);
 133
 134 /*
 135  * Make sure the VMX/Altivec register state in the
 136  * the thread_struct is up to date for task tsk.
 137  */
 138 void flush_altivec_to_thread(struct task_struct *tsk)
 139 {
 140         if (tsk->thread.regs) {
 141                 preempt_disable();
 142                 if (tsk->thread.regs->msr & MSR_VEC) {
 143 #ifdef CONFIG_SMP
 144                         BUG_ON(tsk != current);
 145 #endif
 146                         giveup_altivec(tsk);
 147                 }
 148                 preempt_enable();
 149         }
 150 }
 151 EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
 152 #endif /* CONFIG_ALTIVEC */
 153
 154 #ifdef CONFIG_VSX
 155 #if 0
 156 /* not currently used, but some crazy RAID module might want to later */
 157 void enable_kernel_vsx(void)
 158 {
 159         WARN_ON(preemptible());
 160
 161 #ifdef CONFIG_SMP
 162         if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
 163                 giveup_vsx(current);
 164         else
 165                 giveup_vsx(NULL);       /* just enable vsx for kernel - force */
 166 #else
 167         giveup_vsx(last_task_used_vsx);
 168 #endif /* CONFIG_SMP */
 169 }
 170 EXPORT_SYMBOL(enable_kernel_vsx);
 171 #endif
 172
 173 void giveup_vsx(struct task_struct *tsk)
 174 {
 175         giveup_fpu(tsk);
 176         giveup_altivec(tsk);
 177         __giveup_vsx(tsk);
 178 }
 179
 180 void flush_vsx_to_thread(struct task_struct *tsk)
 181 {
 182         if (tsk->thread.regs) {
 183                 preempt_disable();
 184                 if (tsk->thread.regs->msr & MSR_VSX) {
 185 #ifdef CONFIG_SMP
 186                         BUG_ON(tsk != current);
 187 #endif
 188                         giveup_vsx(tsk);
 189                 }
 190                 preempt_enable();
 191         }
 192 }
 193 EXPORT_SYMBOL_GPL(flush_vsx_to_thread);
 194 #endif /* CONFIG_VSX */
 195
 196 #ifdef CONFIG_SPE
 197
 198 void enable_kernel_spe(void)
 199 {
 200         WARN_ON(preemptible());
 201
 202 #ifdef CONFIG_SMP
 203         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 204                 giveup_spe(current);
 205         else
 206                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 207 #else
 208         giveup_spe(last_task_used_spe);
 209 #endif /* __SMP __ */
 210 }
 211 EXPORT_SYMBOL(enable_kernel_spe);
 212
 213 void flush_spe_to_thread(struct task_struct *tsk)
 214 {
 215         if (tsk->thread.regs) {
 216                 preempt_disable();
 217                 if (tsk->thread.regs->msr & MSR_SPE) {
 218 #ifdef CONFIG_SMP
 219                         BUG_ON(tsk != current);
 220 #endif
 221                         tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
 222                         giveup_spe(tsk);
 223                 }
 224                 preempt_enable();
 225         }
 226 }
 227 #endif /* CONFIG_SPE */
 228
 229 #ifndef CONFIG_SMP
 230 /*
 231  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 232  * and the current task has some state, discard it.
 233  */
 234 void discard_lazy_cpu_state(void)
 235 {
 236         preempt_disable();
 237         if (last_task_used_math == current)
 238                 last_task_used_math = NULL;
 239 #ifdef CONFIG_ALTIVEC
 240         if (last_task_used_altivec == current)
 241                 last_task_used_altivec = NULL;
 242 #endif /* CONFIG_ALTIVEC */
 243 #ifdef CONFIG_VSX
 244         if (last_task_used_vsx == current)
 245                 last_task_used_vsx = NULL;
 246 #endif /* CONFIG_VSX */
 247 #ifdef CONFIG_SPE
 248         if (last_task_used_spe == current)
 249                 last_task_used_spe = NULL;
 250 #endif
 251         preempt_enable();
 252 }
 253 #endif /* CONFIG_SMP */
 254
 255 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 256 void do_send_trap(struct pt_regs *regs, unsigned long address,
 257                   unsigned long error_code, int signal_code, int breakpt)
 258 {
 259         siginfo_t info;
 260
 261         current->thread.trap_nr = signal_code;
 262         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 263                         11, SIGSEGV) == NOTIFY_STOP)
 264                 return;
 265
 266         /* Deliver the signal to userspace */
 267         info.si_signo = SIGTRAP;
 268         info.si_errno = breakpt;        /* breakpoint or watchpoint id */
 269         info.si_code = signal_code;
 270         info.si_addr = (void __user *)address;
 271         force_sig_info(SIGTRAP, &info, current);
 272 }
 273 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
 274 void do_dabr(struct pt_regs *regs, unsigned long address,
 275                     unsigned long error_code)
 276 {
 277         siginfo_t info;
 278
 279         current->thread.trap_nr = TRAP_HWBKPT;
 280         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 281                         11, SIGSEGV) == NOTIFY_STOP)
 282                 return;
 283
 284         if (debugger_dabr_match(regs))
 285                 return;
 286
 287         /* Clear the DABR */
 288         set_dabr(0, 0);
 289
 290         /* Deliver the signal to userspace */
 291         info.si_signo = SIGTRAP;
 292         info.si_errno = 0;
 293         info.si_code = TRAP_HWBKPT;
 294         info.si_addr = (void __user *)address;
 295         force_sig_info(SIGTRAP, &info, current);
 296 }
 297 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
 298
 299 static DEFINE_PER_CPU(unsigned long, current_dabr);
 300
 301 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 302 /*
 303  * Set the debug registers back to their default "safe" values.
 304  */
 305 static void set_debug_reg_defaults(struct thread_struct *thread)
 306 {
 307         thread->iac1 = thread->iac2 = 0;
 308 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 309         thread->iac3 = thread->iac4 = 0;
 310 #endif
 311         thread->dac1 = thread->dac2 = 0;
 312 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 313         thread->dvc1 = thread->dvc2 = 0;
 314 #endif
 315         thread->dbcr0 = 0;
 316 #ifdef CONFIG_BOOKE
 317         /*
 318          * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
 319          */
 320         thread->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |   \
 321                         DBCR1_IAC3US | DBCR1_IAC4US;
 322         /*
 323          * Force Data Address Compare User/Supervisor bits to be User-only
 324          * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
 325          */
 326         thread->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
 327 #else
 328         thread->dbcr1 = 0;
 329 #endif
 330 }
 331
 332 static void prime_debug_regs(struct thread_struct *thread)
 333 {
 334         mtspr(SPRN_IAC1, thread->iac1);
 335         mtspr(SPRN_IAC2, thread->iac2);
 336 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 337         mtspr(SPRN_IAC3, thread->iac3);
 338         mtspr(SPRN_IAC4, thread->iac4);
 339 #endif
 340         mtspr(SPRN_DAC1, thread->dac1);
 341         mtspr(SPRN_DAC2, thread->dac2);
 342 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 343         mtspr(SPRN_DVC1, thread->dvc1);
 344         mtspr(SPRN_DVC2, thread->dvc2);
 345 #endif
 346         mtspr(SPRN_DBCR0, thread->dbcr0);
 347         mtspr(SPRN_DBCR1, thread->dbcr1);
 348 #ifdef CONFIG_BOOKE
 349         mtspr(SPRN_DBCR2, thread->dbcr2);
 350 #endif
 351 }
 352 /*
 353  * Unless neither the old or new thread are making use of the
 354  * debug registers, set the debug registers from the values
 355  * stored in the new thread.
 356  */
 357 static void switch_booke_debug_regs(struct thread_struct *new_thread)
 358 {
 359         if ((current->thread.dbcr0 & DBCR0_IDM)
 360                 || (new_thread->dbcr0 & DBCR0_IDM))
 361                         prime_debug_regs(new_thread);
 362 }
 363 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
 364 #ifndef CONFIG_HAVE_HW_BREAKPOINT
 365 static void set_debug_reg_defaults(struct thread_struct *thread)
 366 {
 367         if (thread->dabr) {
 368                 thread->dabr = 0;
 369                 thread->dabrx = 0;
 370                 set_dabr(0, 0);
 371         }
 372 }
 373 #endif /* !CONFIG_HAVE_HW_BREAKPOINT */
 374 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
 375
 376 int set_dabr(unsigned long dabr, unsigned long dabrx)
 377 {
 378         __get_cpu_var(current_dabr) = dabr;
 379
 380         if (ppc_md.set_dabr)
 381                 return ppc_md.set_dabr(dabr, dabrx);
 382
 383         /* XXX should we have a CPU_FTR_HAS_DABR ? */
 384 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 385         mtspr(SPRN_DAC1, dabr);
 386 #ifdef CONFIG_PPC_47x
 387         isync();
 388 #endif
 389 #elif defined(CONFIG_PPC_BOOK3S)
 390         mtspr(SPRN_DABR, dabr);
 391         mtspr(SPRN_DABRX, dabrx);
 392 #endif
 393         return 0;
 394 }
 395
 396 #ifdef CONFIG_PPC64
 397 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 398 #endif
 399
 400 struct task_struct *__switch_to(struct task_struct *prev,
 401         struct task_struct *new)
 402 {
 403         struct thread_struct *new_thread, *old_thread;
 404         unsigned long flags;
 405         struct task_struct *last;
 406 #ifdef CONFIG_PPC_BOOK3S_64
 407         struct ppc64_tlb_batch *batch;
 408 #endif
 409
 410 #ifdef CONFIG_SMP
 411         /* avoid complexity of lazy save/restore of fpu
 412          * by just saving it every time we switch out if
 413          * this task used the fpu during the last quantum.
 414          *
 415          * If it tries to use the fpu again, it'll trap and
 416          * reload its fp regs.  So we don't have to do a restore
 417          * every switch, just a save.
 418          *  -- Cort
 419          */
 420         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 421                 giveup_fpu(prev);
 422 #ifdef CONFIG_ALTIVEC
 423         /*
 424          * If the previous thread used altivec in the last quantum
 425          * (thus changing altivec regs) then save them.
 426          * We used to check the VRSAVE register but not all apps
 427          * set it, so we don't rely on it now (and in fact we need
 428          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 429          *
 430          * On SMP we always save/restore altivec regs just to avoid the
 431          * complexity of changing processors.
 432          *  -- Cort
 433          */
 434         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 435                 giveup_altivec(prev);
 436 #endif /* CONFIG_ALTIVEC */
 437 #ifdef CONFIG_VSX
 438         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
 439                 /* VMX and FPU registers are already save here */
 440                 __giveup_vsx(prev);
 441 #endif /* CONFIG_VSX */
 442 #ifdef CONFIG_SPE
 443         /*
 444          * If the previous thread used spe in the last quantum
 445          * (thus changing spe regs) then save them.
 446          *
 447          * On SMP we always save/restore spe regs just to avoid the
 448          * complexity of changing processors.
 449          */
 450         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 451                 giveup_spe(prev);
 452 #endif /* CONFIG_SPE */
 453
 454 #else  /* CONFIG_SMP */
 455 #ifdef CONFIG_ALTIVEC
 456         /* Avoid the trap.  On smp this this never happens since
 457          * we don't set last_task_used_altivec -- Cort
 458          */
 459         if (new->thread.regs && last_task_used_altivec == new)
 460                 new->thread.regs->msr |= MSR_VEC;
 461 #endif /* CONFIG_ALTIVEC */
 462 #ifdef CONFIG_VSX
 463         if (new->thread.regs && last_task_used_vsx == new)
 464                 new->thread.regs->msr |= MSR_VSX;
 465 #endif /* CONFIG_VSX */
 466 #ifdef CONFIG_SPE
 467         /* Avoid the trap.  On smp this this never happens since
 468          * we don't set last_task_used_spe
 469          */
 470         if (new->thread.regs && last_task_used_spe == new)
 471                 new->thread.regs->msr |= MSR_SPE;
 472 #endif /* CONFIG_SPE */
 473
 474 #endif /* CONFIG_SMP */
 475
 476 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 477         switch_booke_debug_regs(&new->thread);
 478 #else
 479 /*
 480  * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
 481  * schedule DABR
 482  */
 483 #ifndef CONFIG_HAVE_HW_BREAKPOINT
 484         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
 485                 set_dabr(new->thread.dabr, new->thread.dabrx);
 486 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 487 #endif
 488
 489
 490         new_thread = &new->thread;
 491         old_thread = &current->thread;
 492
 493 #ifdef CONFIG_PPC64
 494         /*
 495          * Collect processor utilization data per process
 496          */
 497         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 498                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 499                 long unsigned start_tb, current_tb;
 500                 start_tb = old_thread->start_tb;
 501                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 502                 old_thread->accum_tb += (current_tb - start_tb);
 503                 new_thread->start_tb = current_tb;
 504         }
 505 #endif /* CONFIG_PPC64 */
 506
 507 #ifdef CONFIG_PPC_BOOK3S_64
 508         batch = &__get_cpu_var(ppc64_tlb_batch);
 509         if (batch->active) {
 510                 current_thread_info()->local_flags |= _TLF_LAZY_MMU;
 511                 if (batch->index)
 512                         __flush_tlb_pending(batch);
 513                 batch->active = 0;
 514         }
 515 #endif /* CONFIG_PPC_BOOK3S_64 */
 516
 517         local_irq_save(flags);
 518
 519         account_system_vtime(current);
 520         account_process_vtime(current);
 521
 522         /*
 523          * We can't take a PMU exception inside _switch() since there is a
 524          * window where the kernel stack SLB and the kernel stack are out
 525          * of sync. Hard disable here.
 526          */
 527         hard_irq_disable();
 528         last = _switch(old_thread, new_thread);
 529
 530 #ifdef CONFIG_PPC_BOOK3S_64
 531         if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
 532                 current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
 533                 batch = &__get_cpu_var(ppc64_tlb_batch);
 534                 batch->active = 1;
 535         }
 536 #endif /* CONFIG_PPC_BOOK3S_64 */
 537
 538         local_irq_restore(flags);
 539
 540         return last;
 541 }
 542
 543 static int instructions_to_print = 16;
 544
 545 static void show_instructions(struct pt_regs *regs)
 546 {
 547         int i;
 548         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 549                         sizeof(int));
 550
 551         printk("Instruction dump:");
 552
 553         for (i = 0; i < instructions_to_print; i++) {
 554                 int instr;
 555
 556                 if (!(i % 8))
 557                         printk("\n");
 558
 559 #if !defined(CONFIG_BOOKE)
 560                 /* If executing with the IMMU off, adjust pc rather
 561                  * than print XXXXXXXX.
 562                  */
 563                 if (!(regs->msr & MSR_IR))
 564                         pc = (unsigned long)phys_to_virt(pc);
 565 #endif
 566
 567                 /* We use __get_user here *only* to avoid an OOPS on a
 568                  * bad address because the pc *should* only be a
 569                  * kernel address.
 570                  */
 571                 if (!__kernel_text_address(pc) ||
 572                      __get_user(instr, (unsigned int __user *)pc)) {
 573                         printk(KERN_CONT "XXXXXXXX ");
 574                 } else {
 575                         if (regs->nip == pc)
 576                                 printk(KERN_CONT "<%08x> ", instr);
 577                         else
 578                                 printk(KERN_CONT "%08x ", instr);
 579                 }
 580
 581                 pc += sizeof(int);
 582         }
 583
 584         printk("\n");
 585 }
 586
 587 static struct regbit {
 588         unsigned long bit;
 589         const char *name;
 590 } msr_bits[] = {
 591 #if defined(CONFIG_PPC64) && !defined(CONFIG_BOOKE)
 592         {MSR_SF,        "SF"},
 593         {MSR_HV,        "HV"},
 594 #endif
 595         {MSR_VEC,       "VEC"},
 596         {MSR_VSX,       "VSX"},
 597 #ifdef CONFIG_BOOKE
 598         {MSR_CE,        "CE"},
 599 #endif
 600         {MSR_EE,        "EE"},
 601         {MSR_PR,        "PR"},
 602         {MSR_FP,        "FP"},
 603         {MSR_ME,        "ME"},
 604 #ifdef CONFIG_BOOKE
 605         {MSR_DE,        "DE"},
 606 #else
 607         {MSR_SE,        "SE"},
 608         {MSR_BE,        "BE"},
 609 #endif
 610         {MSR_IR,        "IR"},
 611         {MSR_DR,        "DR"},
 612         {MSR_PMM,       "PMM"},
 613 #ifndef CONFIG_BOOKE
 614         {MSR_RI,        "RI"},
 615         {MSR_LE,        "LE"},
 616 #endif
 617         {0,             NULL}
 618 };
 619
 620 static void printbits(unsigned long val, struct regbit *bits)
 621 {
 622         const char *sep = "";
 623
 624         printk("<");
 625         for (; bits->bit; ++bits)
 626                 if (val & bits->bit) {
 627                         printk("%s%s", sep, bits->name);
 628                         sep = ",";
 629                 }
 630         printk(">");
 631 }
 632
 633 #ifdef CONFIG_PPC64
 634 #define REG             "%016lx"
 635 #define REGS_PER_LINE   4
 636 #define LAST_VOLATILE   13
 637 #else
 638 #define REG             "%08lx"
 639 #define REGS_PER_LINE   8
 640 #define LAST_VOLATILE   12
 641 #endif
 642
 643 void show_regs(struct pt_regs * regs)
 644 {
 645         int i, trap;
 646
 647         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 648                regs->nip, regs->link, regs->ctr);
 649         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 650                regs, regs->trap, print_tainted(), init_utsname()->release);
 651         printk("MSR: "REG" ", regs->msr);
 652         printbits(regs->msr, msr_bits);
 653         printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
 654 #ifdef CONFIG_PPC64
 655         printk("SOFTE: %ld\n", regs->softe);
 656 #endif
 657         trap = TRAP(regs);
 658         if ((regs->trap != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
 659                 printk("CFAR: "REG"\n", regs->orig_gpr3);
 660         if (trap == 0x300 || trap == 0x600)
 661 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
 662                 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
 663 #else
 664                 printk("DAR: "REG", DSISR: %08lx\n", regs->dar, regs->dsisr);
 665 #endif
 666         printk("TASK = %p[%d] '%s' THREAD: %p",
 667                current, task_pid_nr(current), current->comm, task_thread_info(current));
 668
 669 #ifdef CONFIG_SMP
 670         printk(" CPU: %d", raw_smp_processor_id());
 671 #endif /* CONFIG_SMP */
 672
 673         for (i = 0;  i < 32;  i++) {
 674                 if ((i % REGS_PER_LINE) == 0)
 675                         printk("\nGPR%02d: ", i);
 676                 printk(REG " ", regs->gpr[i]);
 677                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 678                         break;
 679         }
 680         printk("\n");
 681 #ifdef CONFIG_KALLSYMS
 682         /*
 683          * Lookup NIP late so we have the best change of getting the
 684          * above info out without failing
 685          */
 686         printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
 687         printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
 688 #endif
 689         show_stack(current, (unsigned long *) regs->gpr[1]);
 690         if (!user_mode(regs))
 691                 show_instructions(regs);
 692 }
 693
 694 void exit_thread(void)
 695 {
 696         discard_lazy_cpu_state();
 697 }
 698
 699 void flush_thread(void)
 700 {
 701         discard_lazy_cpu_state();
 702
 703 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 704         flush_ptrace_hw_breakpoint(current);
 705 #else /* CONFIG_HAVE_HW_BREAKPOINT */
 706         set_debug_reg_defaults(&current->thread);
 707 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 708 }
 709
 710 void
 711 release_thread(struct task_struct *t)
 712 {
 713 }
 714
 715 /*
 716  * this gets called so that we can store coprocessor state into memory and
 717  * copy the current task into the new thread.
 718  */
 719 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 720 {
 721         flush_fp_to_thread(src);
 722         flush_altivec_to_thread(src);
 723         flush_vsx_to_thread(src);
 724         flush_spe_to_thread(src);
 725 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 726         flush_ptrace_hw_breakpoint(src);
 727 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 728
 729         *dst = *src;
 730         return 0;
 731 }
 732
 733 /*
 734  * Copy a thread..
 735  */
 736 extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
 737
 738 int copy_thread(unsigned long clone_flags, unsigned long usp,
 739                 unsigned long unused, struct task_struct *p,
 740                 struct pt_regs *regs)
 741 {
 742         struct pt_regs *childregs, *kregs;
 743         extern void ret_from_fork(void);
 744         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 745
 746         CHECK_FULL_REGS(regs);
 747         /* Copy registers */
 748         sp -= sizeof(struct pt_regs);
 749         childregs = (struct pt_regs *) sp;
 750         *childregs = *regs;
 751         if ((childregs->msr & MSR_PR) == 0) {
 752                 /* for kernel thread, set `current' and stackptr in new task */
 753                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 754 #ifdef CONFIG_PPC32
 755                 childregs->gpr[2] = (unsigned long) p;
 756 #else
 757                 clear_tsk_thread_flag(p, TIF_32BIT);
 758 #endif
 759                 p->thread.regs = NULL;  /* no user register state */
 760         } else {
 761                 childregs->gpr[1] = usp;
 762                 p->thread.regs = childregs;
 763                 if (clone_flags & CLONE_SETTLS) {
 764 #ifdef CONFIG_PPC64
 765                         if (!is_32bit_task())
 766                                 childregs->gpr[13] = childregs->gpr[6];
 767                         else
 768 #endif
 769                                 childregs->gpr[2] = childregs->gpr[6];
 770                 }
 771         }
 772         childregs->gpr[3] = 0;  /* Result from fork() */
 773         sp -= STACK_FRAME_OVERHEAD;
 774
 775         /*
 776          * The way this works is that at some point in the future
 777          * some task will call _switch to switch to the new task.
 778          * That will pop off the stack frame created below and start
 779          * the new task running at ret_from_fork.  The new task will
 780          * do some house keeping and then return from the fork or clone
 781          * system call, using the stack frame created above.
 782          */
 783         sp -= sizeof(struct pt_regs);
 784         kregs = (struct pt_regs *) sp;
 785         sp -= STACK_FRAME_OVERHEAD;
 786         p->thread.ksp = sp;
 787         p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
 788                                 _ALIGN_UP(sizeof(struct thread_info), 16);
 789
 790 #ifdef CONFIG_PPC_STD_MMU_64
 791         if (mmu_has_feature(MMU_FTR_SLB)) {
 792                 unsigned long sp_vsid;
 793                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 794
 795                 if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
 796                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
 797                                 << SLB_VSID_SHIFT_1T;
 798                 else
 799                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
 800                                 << SLB_VSID_SHIFT;
 801                 sp_vsid |= SLB_VSID_KERNEL | llp;
 802                 p->thread.ksp_vsid = sp_vsid;
 803         }
 804 #endif /* CONFIG_PPC_STD_MMU_64 */
 805 #ifdef CONFIG_PPC64
 806         if (cpu_has_feature(CPU_FTR_DSCR)) {
 807                 p->thread.dscr_inherit = current->thread.dscr_inherit;
 808                 p->thread.dscr = current->thread.dscr;
 809         }
 810 #endif
 811
 812         /*
 813          * The PPC64 ABI makes use of a TOC to contain function
 814          * pointers.  The function (ret_from_except) is actually a pointer
 815          * to the TOC entry.  The first entry is a pointer to the actual
 816          * function.
 817          */
 818 #ifdef CONFIG_PPC64
 819         kregs->nip = *((unsigned long *)ret_from_fork);
 820 #else
 821         kregs->nip = (unsigned long)ret_from_fork;
 822 #endif
 823
 824         return 0;
 825 }
 826
 827 /*
 828  * Set up a thread for executing a new program
 829  */
 830 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 831 {
 832 #ifdef CONFIG_PPC64
 833         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 834 #endif
 835
 836         /*
 837          * If we exec out of a kernel thread then thread.regs will not be
 838          * set.  Do it now.
 839          */
 840         if (!current->thread.regs) {
 841                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
 842                 current->thread.regs = regs - 1;
 843         }
 844
 845         memset(regs->gpr, 0, sizeof(regs->gpr));
 846         regs->ctr = 0;
 847         regs->link = 0;
 848         regs->xer = 0;
 849         regs->ccr = 0;
 850         regs->gpr[1] = sp;
 851
 852         /*
 853          * We have just cleared all the nonvolatile GPRs, so make
 854          * FULL_REGS(regs) return true.  This is necessary to allow
 855          * ptrace to examine the thread immediately after exec.
 856          */
 857         regs->trap &= ~1UL;
 858
 859 #ifdef CONFIG_PPC32
 860         regs->mq = 0;
 861         regs->nip = start;
 862         regs->msr = MSR_USER;
 863 #else
 864         if (!is_32bit_task()) {
 865                 unsigned long entry, toc;
 866
 867                 /* start is a relocated pointer to the function descriptor for
 868                  * the elf _start routine.  The first entry in the function
 869                  * descriptor is the entry address of _start and the second
 870                  * entry is the TOC value we need to use.
 871                  */
 872                 __get_user(entry, (unsigned long __user *)start);
 873                 __get_user(toc, (unsigned long __user *)start+1);
 874
 875                 /* Check whether the e_entry function descriptor entries
 876                  * need to be relocated before we can use them.
 877                  */
 878                 if (load_addr != 0) {
 879                         entry += load_addr;
 880                         toc   += load_addr;
 881                 }
 882                 regs->nip = entry;
 883                 regs->gpr[2] = toc;
 884                 regs->msr = MSR_USER64;
 885         } else {
 886                 regs->nip = start;
 887                 regs->gpr[2] = 0;
 888                 regs->msr = MSR_USER32;
 889         }
 890 #endif
 891
 892         discard_lazy_cpu_state();
 893 #ifdef CONFIG_VSX
 894         current->thread.used_vsr = 0;
 895 #endif
 896         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 897         current->thread.fpscr.val = 0;
 898 #ifdef CONFIG_ALTIVEC
 899         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 900         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 901         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 902         current->thread.vrsave = 0;
 903         current->thread.used_vr = 0;
 904 #endif /* CONFIG_ALTIVEC */
 905 #ifdef CONFIG_SPE
 906         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 907         current->thread.acc = 0;
 908         current->thread.spefscr = 0;
 909         current->thread.used_spe = 0;
 910 #endif /* CONFIG_SPE */
 911 }
 912
 913 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 914                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 915
 916 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 917 {
 918         struct pt_regs *regs = tsk->thread.regs;
 919
 920         /* This is a bit hairy.  If we are an SPE enabled  processor
 921          * (have embedded fp) we store the IEEE exception enable flags in
 922          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 923          * mode (asyn, precise, disabled) for 'Classic' FP. */
 924         if (val & PR_FP_EXC_SW_ENABLE) {
 925 #ifdef CONFIG_SPE
 926                 if (cpu_has_feature(CPU_FTR_SPE)) {
 927                         tsk->thread.fpexc_mode = val &
 928                                 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 929                         return 0;
 930                 } else {
 931                         return -EINVAL;
 932                 }
 933 #else
 934                 return -EINVAL;
 935 #endif
 936         }
 937
 938         /* on a CONFIG_SPE this does not hurt us.  The bits that
 939          * __pack_fe01 use do not overlap with bits used for
 940          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 941          * on CONFIG_SPE implementations are reserved so writing to
 942          * them does not change anything */
 943         if (val > PR_FP_EXC_PRECISE)
 944                 return -EINVAL;
 945         tsk->thread.fpexc_mode = __pack_fe01(val);
 946         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 947                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 948                         | tsk->thread.fpexc_mode;
 949         return 0;
 950 }
 951
 952 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 953 {
 954         unsigned int val;
 955
 956         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 957 #ifdef CONFIG_SPE
 958                 if (cpu_has_feature(CPU_FTR_SPE))
 959                         val = tsk->thread.fpexc_mode;
 960                 else
 961                         return -EINVAL;
 962 #else
 963                 return -EINVAL;
 964 #endif
 965         else
 966                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 967         return put_user(val, (unsigned int __user *) adr);
 968 }
 969
 970 int set_endian(struct task_struct *tsk, unsigned int val)
 971 {
 972         struct pt_regs *regs = tsk->thread.regs;
 973
 974         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
 975             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
 976                 return -EINVAL;
 977
 978         if (regs == NULL)
 979                 return -EINVAL;
 980
 981         if (val == PR_ENDIAN_BIG)
 982                 regs->msr &= ~MSR_LE;
 983         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
 984                 regs->msr |= MSR_LE;
 985         else
 986                 return -EINVAL;
 987
 988         return 0;
 989 }
 990
 991 int get_endian(struct task_struct *tsk, unsigned long adr)
 992 {
 993         struct pt_regs *regs = tsk->thread.regs;
 994         unsigned int val;
 995
 996         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
 997             !cpu_has_feature(CPU_FTR_REAL_LE))
 998                 return -EINVAL;
 999
1000         if (regs == NULL)
1001                 return -EINVAL;
1002
1003         if (regs->msr & MSR_LE) {
1004                 if (cpu_has_feature(CPU_FTR_REAL_LE))
1005                         val = PR_ENDIAN_LITTLE;
1006                 else
1007                         val = PR_ENDIAN_PPC_LITTLE;
1008         } else
1009                 val = PR_ENDIAN_BIG;
1010
1011         return put_user(val, (unsigned int __user *)adr);
1012 }
1013
1014 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
1015 {
1016         tsk->thread.align_ctl = val;
1017         return 0;
1018 }
1019
1020 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
1021 {
1022         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
1023 }
1024
1025 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
1026
1027 int sys_clone(unsigned long clone_flags, unsigned long usp,
1028               int __user *parent_tidp, void __user *child_threadptr,
1029               int __user *child_tidp, int p6,
1030               struct pt_regs *regs)
1031 {
1032         CHECK_FULL_REGS(regs);
1033         if (usp == 0)
1034                 usp = regs->gpr[1];     /* stack pointer for child */
1035 #ifdef CONFIG_PPC64
1036         if (is_32bit_task()) {
1037                 parent_tidp = TRUNC_PTR(parent_tidp);
1038                 child_tidp = TRUNC_PTR(child_tidp);
1039         }
1040 #endif
1041         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
1042 }
1043
1044 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
1045              unsigned long p4, unsigned long p5, unsigned long p6,
1046              struct pt_regs *regs)
1047 {
1048         CHECK_FULL_REGS(regs);
1049         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
1050 }
1051
1052 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
1053               unsigned long p4, unsigned long p5, unsigned long p6,
1054               struct pt_regs *regs)
1055 {
1056         CHECK_FULL_REGS(regs);
1057         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
1058                         regs, 0, NULL, NULL);
1059 }
1060
1061 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
1062                unsigned long a3, unsigned long a4, unsigned long a5,
1063                struct pt_regs *regs)
1064 {
1065         int error;
1066         char *filename;
1067
1068         filename = getname((const char __user *) a0);
1069         error = PTR_ERR(filename);
1070         if (IS_ERR(filename))
1071                 goto out;
1072         flush_fp_to_thread(current);
1073         flush_altivec_to_thread(current);
1074         flush_spe_to_thread(current);
1075         error = do_execve(filename,
1076                           (const char __user *const __user *) a1,
1077                           (const char __user *const __user *) a2, regs);
1078         putname(filename);
1079 out:
1080         return error;
1081 }
1082
1083 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
1084                                   unsigned long nbytes)
1085 {
1086         unsigned long stack_page;
1087         unsigned long cpu = task_cpu(p);
1088
1089         /*
1090          * Avoid crashing if the stack has overflowed and corrupted
1091          * task_cpu(p), which is in the thread_info struct.
1092          */
1093         if (cpu < NR_CPUS && cpu_possible(cpu)) {
1094                 stack_page = (unsigned long) hardirq_ctx[cpu];
1095                 if (sp >= stack_page + sizeof(struct thread_struct)
1096                     && sp <= stack_page + THREAD_SIZE - nbytes)
1097                         return 1;
1098
1099                 stack_page = (unsigned long) softirq_ctx[cpu];
1100                 if (sp >= stack_page + sizeof(struct thread_struct)
1101                     && sp <= stack_page + THREAD_SIZE - nbytes)
1102                         return 1;
1103         }
1104         return 0;
1105 }
1106
1107 int validate_sp(unsigned long sp, struct task_struct *p,
1108                        unsigned long nbytes)
1109 {
1110         unsigned long stack_page = (unsigned long)task_stack_page(p);
1111
1112         if (sp >= stack_page + sizeof(struct thread_struct)
1113             && sp <= stack_page + THREAD_SIZE - nbytes)
1114                 return 1;
1115
1116         return valid_irq_stack(sp, p, nbytes);
1117 }
1118
1119 EXPORT_SYMBOL(validate_sp);
1120
1121 unsigned long get_wchan(struct task_struct *p)
1122 {
1123         unsigned long ip, sp;
1124         int count = 0;
1125
1126         if (!p || p == current || p->state == TASK_RUNNING)
1127                 return 0;
1128
1129         sp = p->thread.ksp;
1130         if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1131                 return 0;
1132
1133         do {
1134                 sp = *(unsigned long *)sp;
1135                 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1136                         return 0;
1137                 if (count > 0) {
1138                         ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1139                         if (!in_sched_functions(ip))
1140                                 return ip;
1141                 }
1142         } while (count++ < 16);
1143         return 0;
1144 }
1145
1146 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1147
1148 void show_stack(struct task_struct *tsk, unsigned long *stack)
1149 {
1150         unsigned long sp, ip, lr, newsp;
1151         int count = 0;
1152         int firstframe = 1;
1153 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1154         int curr_frame = current->curr_ret_stack;
1155         extern void return_to_handler(void);
1156         unsigned long rth = (unsigned long)return_to_handler;
1157         unsigned long mrth = -1;
1158 #ifdef CONFIG_PPC64
1159         extern void mod_return_to_handler(void);
1160         rth = *(unsigned long *)rth;
1161         mrth = (unsigned long)mod_return_to_handler;
1162         mrth = *(unsigned long *)mrth;
1163 #endif
1164 #endif
1165
1166         sp = (unsigned long) stack;
1167         if (tsk == NULL)
1168                 tsk = current;
1169         if (sp == 0) {
1170                 if (tsk == current)
1171                         asm("mr %0,1" : "=r" (sp));
1172                 else
1173                         sp = tsk->thread.ksp;
1174         }
1175
1176         lr = 0;
1177         printk("Call Trace:\n");
1178         do {
1179                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1180                         return;
1181
1182                 stack = (unsigned long *) sp;
1183                 newsp = stack[0];
1184                 ip = stack[STACK_FRAME_LR_SAVE];
1185                 if (!firstframe || ip != lr) {
1186                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1187 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1188                         if ((ip == rth || ip == mrth) && curr_frame >= 0) {
1189                                 printk(" (%pS)",
1190                                        (void *)current->ret_stack[curr_frame].ret);
1191                                 curr_frame--;
1192                         }
1193 #endif
1194                         if (firstframe)
1195                                 printk(" (unreliable)");
1196                         printk("\n");
1197                 }
1198                 firstframe = 0;
1199
1200                 /*
1201                  * See if this is an exception frame.
1202                  * We look for the "regshere" marker in the current frame.
1203                  */
1204                 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1205                     && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1206                         struct pt_regs *regs = (struct pt_regs *)
1207                                 (sp + STACK_FRAME_OVERHEAD);
1208                         lr = regs->link;
1209                         printk("--- Exception: %lx at %pS\n    LR = %pS\n",
1210                                regs->trap, (void *)regs->nip, (void *)lr);
1211                         firstframe = 1;
1212                 }
1213
1214                 sp = newsp;
1215         } while (count++ < kstack_depth_to_print);
1216 }
1217
1218 void dump_stack(void)
1219 {
1220         show_stack(current, NULL);
1221 }
1222 EXPORT_SYMBOL(dump_stack);
1223
1224 #ifdef CONFIG_PPC64
1225 /* Called with hard IRQs off */
1226 void __ppc64_runlatch_on(void)
1227 {
1228         struct thread_info *ti = current_thread_info();
1229         unsigned long ctrl;
1230
1231         ctrl = mfspr(SPRN_CTRLF);
1232         ctrl |= CTRL_RUNLATCH;
1233         mtspr(SPRN_CTRLT, ctrl);
1234
1235         ti->local_flags |= _TLF_RUNLATCH;
1236 }
1237
1238 /* Called with hard IRQs off */
1239 void __ppc64_runlatch_off(void)
1240 {
1241         struct thread_info *ti = current_thread_info();
1242         unsigned long ctrl;
1243
1244         ti->local_flags &= ~_TLF_RUNLATCH;
1245
1246         ctrl = mfspr(SPRN_CTRLF);
1247         ctrl &= ~CTRL_RUNLATCH;
1248         mtspr(SPRN_CTRLT, ctrl);
1249 }
1250 #endif /* CONFIG_PPC64 */
1251
1252 unsigned long arch_align_stack(unsigned long sp)
1253 {
1254         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
1255                 sp -= get_random_int() & ~PAGE_MASK;
1256         return sp & ~0xf;
1257 }
1258
1259 static inline unsigned long brk_rnd(void)
1260 {
1261         unsigned long rnd = 0;
1262
1263         /* 8MB for 32bit, 1GB for 64bit */
1264         if (is_32bit_task())
1265                 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
1266         else
1267                 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
1268
1269         return rnd << PAGE_SHIFT;
1270 }
1271
1272 unsigned long arch_randomize_brk(struct mm_struct *mm)
1273 {
1274         unsigned long base = mm->brk;
1275         unsigned long ret;
1276
1277 #ifdef CONFIG_PPC_STD_MMU_64
1278         /*
1279          * If we are using 1TB segments and we are allowed to randomise
1280          * the heap, we can put it above 1TB so it is backed by a 1TB
1281          * segment. Otherwise the heap will be in the bottom 1TB
1282          * which always uses 256MB segments and this may result in a
1283          * performance penalty.
1284          */
1285         if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
1286                 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
1287 #endif
1288
1289         ret = PAGE_ALIGN(base + brk_rnd());
1290
1291         if (ret < mm->brk)
1292                 return mm->brk;
1293
1294         return ret;
1295 }
1296
1297 unsigned long randomize_et_dyn(unsigned long base)
1298 {
1299         unsigned long ret = PAGE_ALIGN(base + brk_rnd());
1300
1301         if (ret < base)
1302                 return base;
1303
1304         return ret;
1305 }