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