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         account_system_vtime(current);
 518         account_process_vtime(current);
 519
 520         /*
 521          * We can't take a PMU exception inside _switch() since there is a
 522          * window where the kernel stack SLB and the kernel stack are out
 523          * of sync. Hard disable here.
 524          */
 525         hard_irq_disable();
 526         last = _switch(old_thread, new_thread);
 527
 528 #ifdef CONFIG_PPC_BOOK3S_64
 529         if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
 530                 current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
 531                 batch = &__get_cpu_var(ppc64_tlb_batch);
 532                 batch->active = 1;
 533         }
 534 #endif /* CONFIG_PPC_BOOK3S_64 */
 535
 536         local_irq_restore(flags);
 537
 538         return last;
 539 }
 540
 541 static int instructions_to_print = 16;
 542
 543 static void show_instructions(struct pt_regs *regs)
 544 {
 545         int i;
 546         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 547                         sizeof(int));
 548
 549         printk("Instruction dump:");
 550
 551         for (i = 0; i < instructions_to_print; i++) {
 552                 int instr;
 553
 554                 if (!(i % 8))
 555                         printk("\n");
 556
 557 #if !defined(CONFIG_BOOKE)
 558                 /* If executing with the IMMU off, adjust pc rather
 559                  * than print XXXXXXXX.
 560                  */
 561                 if (!(regs->msr & MSR_IR))
 562                         pc = (unsigned long)phys_to_virt(pc);
 563 #endif
 564
 565                 /* We use __get_user here *only* to avoid an OOPS on a
 566                  * bad address because the pc *should* only be a
 567                  * kernel address.
 568                  */
 569                 if (!__kernel_text_address(pc) ||
 570                      __get_user(instr, (unsigned int __user *)pc)) {
 571                         printk(KERN_CONT "XXXXXXXX ");
 572                 } else {
 573                         if (regs->nip == pc)
 574                                 printk(KERN_CONT "<%08x> ", instr);
 575                         else
 576                                 printk(KERN_CONT "%08x ", instr);
 577                 }
 578
 579                 pc += sizeof(int);
 580         }
 581
 582         printk("\n");
 583 }
 584
 585 static struct regbit {
 586         unsigned long bit;
 587         const char *name;
 588 } msr_bits[] = {
 589 #if defined(CONFIG_PPC64) && !defined(CONFIG_BOOKE)
 590         {MSR_SF,        "SF"},
 591         {MSR_HV,        "HV"},
 592 #endif
 593         {MSR_VEC,       "VEC"},
 594         {MSR_VSX,       "VSX"},
 595 #ifdef CONFIG_BOOKE
 596         {MSR_CE,        "CE"},
 597 #endif
 598         {MSR_EE,        "EE"},
 599         {MSR_PR,        "PR"},
 600         {MSR_FP,        "FP"},
 601         {MSR_ME,        "ME"},
 602 #ifdef CONFIG_BOOKE
 603         {MSR_DE,        "DE"},
 604 #else
 605         {MSR_SE,        "SE"},
 606         {MSR_BE,        "BE"},
 607 #endif
 608         {MSR_IR,        "IR"},
 609         {MSR_DR,        "DR"},
 610         {MSR_PMM,       "PMM"},
 611 #ifndef CONFIG_BOOKE
 612         {MSR_RI,        "RI"},
 613         {MSR_LE,        "LE"},
 614 #endif
 615         {0,             NULL}
 616 };
 617
 618 static void printbits(unsigned long val, struct regbit *bits)
 619 {
 620         const char *sep = "";
 621
 622         printk("<");
 623         for (; bits->bit; ++bits)
 624                 if (val & bits->bit) {
 625                         printk("%s%s", sep, bits->name);
 626                         sep = ",";
 627                 }
 628         printk(">");
 629 }
 630
 631 #ifdef CONFIG_PPC64
 632 #define REG             "%016lx"
 633 #define REGS_PER_LINE   4
 634 #define LAST_VOLATILE   13
 635 #else
 636 #define REG             "%08lx"
 637 #define REGS_PER_LINE   8
 638 #define LAST_VOLATILE   12
 639 #endif
 640
 641 void show_regs(struct pt_regs * regs)
 642 {
 643         int i, trap;
 644
 645         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 646                regs->nip, regs->link, regs->ctr);
 647         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 648                regs, regs->trap, print_tainted(), init_utsname()->release);
 649         printk("MSR: "REG" ", regs->msr);
 650         printbits(regs->msr, msr_bits);
 651         printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
 652 #ifdef CONFIG_PPC64
 653         printk("SOFTE: %ld\n", regs->softe);
 654 #endif
 655         trap = TRAP(regs);
 656         if ((regs->trap != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
 657                 printk("CFAR: "REG"\n", regs->orig_gpr3);
 658         if (trap == 0x300 || trap == 0x600)
 659 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
 660                 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
 661 #else
 662                 printk("DAR: "REG", DSISR: %08lx\n", regs->dar, regs->dsisr);
 663 #endif
 664         printk("TASK = %p[%d] '%s' THREAD: %p",
 665                current, task_pid_nr(current), current->comm, task_thread_info(current));
 666
 667 #ifdef CONFIG_SMP
 668         printk(" CPU: %d", raw_smp_processor_id());
 669 #endif /* CONFIG_SMP */
 670
 671         for (i = 0;  i < 32;  i++) {
 672                 if ((i % REGS_PER_LINE) == 0)
 673                         printk("\nGPR%02d: ", i);
 674                 printk(REG " ", regs->gpr[i]);
 675                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 676                         break;
 677         }
 678         printk("\n");
 679 #ifdef CONFIG_KALLSYMS
 680         /*
 681          * Lookup NIP late so we have the best change of getting the
 682          * above info out without failing
 683          */
 684         printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
 685         printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
 686 #endif
 687         show_stack(current, (unsigned long *) regs->gpr[1]);
 688         if (!user_mode(regs))
 689                 show_instructions(regs);
 690 }
 691
 692 void exit_thread(void)
 693 {
 694         discard_lazy_cpu_state();
 695 }
 696
 697 void flush_thread(void)
 698 {
 699         discard_lazy_cpu_state();
 700
 701 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 702         flush_ptrace_hw_breakpoint(current);
 703 #else /* CONFIG_HAVE_HW_BREAKPOINT */
 704         set_debug_reg_defaults(&current->thread);
 705 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 706 }
 707
 708 void
 709 release_thread(struct task_struct *t)
 710 {
 711 }
 712
 713 /*
 714  * this gets called so that we can store coprocessor state into memory and
 715  * copy the current task into the new thread.
 716  */
 717 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 718 {
 719         flush_fp_to_thread(src);
 720         flush_altivec_to_thread(src);
 721         flush_vsx_to_thread(src);
 722         flush_spe_to_thread(src);
 723 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 724         flush_ptrace_hw_breakpoint(src);
 725 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 726
 727         *dst = *src;
 728         return 0;
 729 }
 730
 731 /*
 732  * Copy a thread..
 733  */
 734 extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
 735
 736 int copy_thread(unsigned long clone_flags, unsigned long usp,
 737                 unsigned long unused, struct task_struct *p,
 738                 struct pt_regs *regs)
 739 {
 740         struct pt_regs *childregs, *kregs;
 741         extern void ret_from_fork(void);
 742         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 743
 744         CHECK_FULL_REGS(regs);
 745         /* Copy registers */
 746         sp -= sizeof(struct pt_regs);
 747         childregs = (struct pt_regs *) sp;
 748         *childregs = *regs;
 749         if ((childregs->msr & MSR_PR) == 0) {
 750                 /* for kernel thread, set `current' and stackptr in new task */
 751                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 752 #ifdef CONFIG_PPC32
 753                 childregs->gpr[2] = (unsigned long) p;
 754 #else
 755                 clear_tsk_thread_flag(p, TIF_32BIT);
 756 #endif
 757                 p->thread.regs = NULL;  /* no user register state */
 758         } else {
 759                 childregs->gpr[1] = usp;
 760                 p->thread.regs = childregs;
 761                 if (clone_flags & CLONE_SETTLS) {
 762 #ifdef CONFIG_PPC64
 763                         if (!is_32bit_task())
 764                                 childregs->gpr[13] = childregs->gpr[6];
 765                         else
 766 #endif
 767                                 childregs->gpr[2] = childregs->gpr[6];
 768                 }
 769         }
 770         childregs->gpr[3] = 0;  /* Result from fork() */
 771         sp -= STACK_FRAME_OVERHEAD;
 772
 773         /*
 774          * The way this works is that at some point in the future
 775          * some task will call _switch to switch to the new task.
 776          * That will pop off the stack frame created below and start
 777          * the new task running at ret_from_fork.  The new task will
 778          * do some house keeping and then return from the fork or clone
 779          * system call, using the stack frame created above.
 780          */
 781         sp -= sizeof(struct pt_regs);
 782         kregs = (struct pt_regs *) sp;
 783         sp -= STACK_FRAME_OVERHEAD;
 784         p->thread.ksp = sp;
 785         p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
 786                                 _ALIGN_UP(sizeof(struct thread_info), 16);
 787
 788 #ifdef CONFIG_PPC_STD_MMU_64
 789         if (mmu_has_feature(MMU_FTR_SLB)) {
 790                 unsigned long sp_vsid;
 791                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 792
 793                 if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
 794                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
 795                                 << SLB_VSID_SHIFT_1T;
 796                 else
 797                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
 798                                 << SLB_VSID_SHIFT;
 799                 sp_vsid |= SLB_VSID_KERNEL | llp;
 800                 p->thread.ksp_vsid = sp_vsid;
 801         }
 802 #endif /* CONFIG_PPC_STD_MMU_64 */
 803 #ifdef CONFIG_PPC64
 804         if (cpu_has_feature(CPU_FTR_DSCR)) {
 805                 p->thread.dscr_inherit = current->thread.dscr_inherit;
 806                 p->thread.dscr = current->thread.dscr;
 807         }
 808 #endif
 809
 810         /*
 811          * The PPC64 ABI makes use of a TOC to contain function
 812          * pointers.  The function (ret_from_except) is actually a pointer
 813          * to the TOC entry.  The first entry is a pointer to the actual
 814          * function.
 815          */
 816 #ifdef CONFIG_PPC64
 817         kregs->nip = *((unsigned long *)ret_from_fork);
 818 #else
 819         kregs->nip = (unsigned long)ret_from_fork;
 820 #endif
 821
 822         return 0;
 823 }
 824
 825 /*
 826  * Set up a thread for executing a new program
 827  */
 828 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 829 {
 830 #ifdef CONFIG_PPC64
 831         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 832 #endif
 833
 834         /*
 835          * If we exec out of a kernel thread then thread.regs will not be
 836          * set.  Do it now.
 837          */
 838         if (!current->thread.regs) {
 839                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
 840                 current->thread.regs = regs - 1;
 841         }
 842
 843         memset(regs->gpr, 0, sizeof(regs->gpr));
 844         regs->ctr = 0;
 845         regs->link = 0;
 846         regs->xer = 0;
 847         regs->ccr = 0;
 848         regs->gpr[1] = sp;
 849
 850         /*
 851          * We have just cleared all the nonvolatile GPRs, so make
 852          * FULL_REGS(regs) return true.  This is necessary to allow
 853          * ptrace to examine the thread immediately after exec.
 854          */
 855         regs->trap &= ~1UL;
 856
 857 #ifdef CONFIG_PPC32
 858         regs->mq = 0;
 859         regs->nip = start;
 860         regs->msr = MSR_USER;
 861 #else
 862         if (!is_32bit_task()) {
 863                 unsigned long entry, toc;
 864
 865                 /* start is a relocated pointer to the function descriptor for
 866                  * the elf _start routine.  The first entry in the function
 867                  * descriptor is the entry address of _start and the second
 868                  * entry is the TOC value we need to use.
 869                  */
 870                 __get_user(entry, (unsigned long __user *)start);
 871                 __get_user(toc, (unsigned long __user *)start+1);
 872
 873                 /* Check whether the e_entry function descriptor entries
 874                  * need to be relocated before we can use them.
 875                  */
 876                 if (load_addr != 0) {
 877                         entry += load_addr;
 878                         toc   += load_addr;
 879                 }
 880                 regs->nip = entry;
 881                 regs->gpr[2] = toc;
 882                 regs->msr = MSR_USER64;
 883         } else {
 884                 regs->nip = start;
 885                 regs->gpr[2] = 0;
 886                 regs->msr = MSR_USER32;
 887         }
 888 #endif
 889
 890         discard_lazy_cpu_state();
 891 #ifdef CONFIG_VSX
 892         current->thread.used_vsr = 0;
 893 #endif
 894         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 895         current->thread.fpscr.val = 0;
 896 #ifdef CONFIG_ALTIVEC
 897         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 898         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 899         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 900         current->thread.vrsave = 0;
 901         current->thread.used_vr = 0;
 902 #endif /* CONFIG_ALTIVEC */
 903 #ifdef CONFIG_SPE
 904         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 905         current->thread.acc = 0;
 906         current->thread.spefscr = 0;
 907         current->thread.used_spe = 0;
 908 #endif /* CONFIG_SPE */
 909 }
 910
 911 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 912                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 913
 914 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 915 {
 916         struct pt_regs *regs = tsk->thread.regs;
 917
 918         /* This is a bit hairy.  If we are an SPE enabled  processor
 919          * (have embedded fp) we store the IEEE exception enable flags in
 920          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 921          * mode (asyn, precise, disabled) for 'Classic' FP. */
 922         if (val & PR_FP_EXC_SW_ENABLE) {
 923 #ifdef CONFIG_SPE
 924                 if (cpu_has_feature(CPU_FTR_SPE)) {
 925                         tsk->thread.fpexc_mode = val &
 926                                 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 927                         return 0;
 928                 } else {
 929                         return -EINVAL;
 930                 }
 931 #else
 932                 return -EINVAL;
 933 #endif
 934         }
 935
 936         /* on a CONFIG_SPE this does not hurt us.  The bits that
 937          * __pack_fe01 use do not overlap with bits used for
 938          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 939          * on CONFIG_SPE implementations are reserved so writing to
 940          * them does not change anything */
 941         if (val > PR_FP_EXC_PRECISE)
 942                 return -EINVAL;
 943         tsk->thread.fpexc_mode = __pack_fe01(val);
 944         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 945                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 946                         | tsk->thread.fpexc_mode;
 947         return 0;
 948 }
 949
 950 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 951 {
 952         unsigned int val;
 953
 954         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 955 #ifdef CONFIG_SPE
 956                 if (cpu_has_feature(CPU_FTR_SPE))
 957                         val = tsk->thread.fpexc_mode;
 958                 else
 959                         return -EINVAL;
 960 #else
 961                 return -EINVAL;
 962 #endif
 963         else
 964                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 965         return put_user(val, (unsigned int __user *) adr);
 966 }
 967
 968 int set_endian(struct task_struct *tsk, unsigned int val)
 969 {
 970         struct pt_regs *regs = tsk->thread.regs;
 971
 972         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
 973             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
 974                 return -EINVAL;
 975
 976         if (regs == NULL)
 977                 return -EINVAL;
 978
 979         if (val == PR_ENDIAN_BIG)
 980                 regs->msr &= ~MSR_LE;
 981         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
 982                 regs->msr |= MSR_LE;
 983         else
 984                 return -EINVAL;
 985
 986         return 0;
 987 }
 988
 989 int get_endian(struct task_struct *tsk, unsigned long adr)
 990 {
 991         struct pt_regs *regs = tsk->thread.regs;
 992         unsigned int val;
 993
 994         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
 995             !cpu_has_feature(CPU_FTR_REAL_LE))
 996                 return -EINVAL;
 997
 998         if (regs == NULL)
 999                 return -EINVAL;
1000
1001         if (regs->msr & MSR_LE) {
1002                 if (cpu_has_feature(CPU_FTR_REAL_LE))
1003                         val = PR_ENDIAN_LITTLE;
1004                 else
1005                         val = PR_ENDIAN_PPC_LITTLE;
1006         } else
1007                 val = PR_ENDIAN_BIG;
1008
1009         return put_user(val, (unsigned int __user *)adr);
1010 }
1011
1012 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
1013 {
1014         tsk->thread.align_ctl = val;
1015         return 0;
1016 }
1017
1018 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
1019 {
1020         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
1021 }
1022
1023 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
1024
1025 int sys_clone(unsigned long clone_flags, unsigned long usp,
1026               int __user *parent_tidp, void __user *child_threadptr,
1027               int __user *child_tidp, int p6,
1028               struct pt_regs *regs)
1029 {
1030         CHECK_FULL_REGS(regs);
1031         if (usp == 0)
1032                 usp = regs->gpr[1];     /* stack pointer for child */
1033 #ifdef CONFIG_PPC64
1034         if (is_32bit_task()) {
1035                 parent_tidp = TRUNC_PTR(parent_tidp);
1036                 child_tidp = TRUNC_PTR(child_tidp);
1037         }
1038 #endif
1039         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
1040 }
1041
1042 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
1043              unsigned long p4, unsigned long p5, unsigned long p6,
1044              struct pt_regs *regs)
1045 {
1046         CHECK_FULL_REGS(regs);
1047         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
1048 }
1049
1050 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
1051               unsigned long p4, unsigned long p5, unsigned long p6,
1052               struct pt_regs *regs)
1053 {
1054         CHECK_FULL_REGS(regs);
1055         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
1056                         regs, 0, NULL, NULL);
1057 }
1058
1059 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
1060                unsigned long a3, unsigned long a4, unsigned long a5,
1061                struct pt_regs *regs)
1062 {
1063         int error;
1064         char *filename;
1065
1066         filename = getname((const char __user *) a0);
1067         error = PTR_ERR(filename);
1068         if (IS_ERR(filename))
1069                 goto out;
1070         flush_fp_to_thread(current);
1071         flush_altivec_to_thread(current);
1072         flush_spe_to_thread(current);
1073         error = do_execve(filename,
1074                           (const char __user *const __user *) a1,
1075                           (const char __user *const __user *) a2, regs);
1076         putname(filename);
1077 out:
1078         return error;
1079 }
1080
1081 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
1082                                   unsigned long nbytes)
1083 {
1084         unsigned long stack_page;
1085         unsigned long cpu = task_cpu(p);
1086
1087         /*
1088          * Avoid crashing if the stack has overflowed and corrupted
1089          * task_cpu(p), which is in the thread_info struct.
1090          */
1091         if (cpu < NR_CPUS && cpu_possible(cpu)) {
1092                 stack_page = (unsigned long) hardirq_ctx[cpu];
1093                 if (sp >= stack_page + sizeof(struct thread_struct)
1094                     && sp <= stack_page + THREAD_SIZE - nbytes)
1095                         return 1;
1096
1097                 stack_page = (unsigned long) softirq_ctx[cpu];
1098                 if (sp >= stack_page + sizeof(struct thread_struct)
1099                     && sp <= stack_page + THREAD_SIZE - nbytes)
1100                         return 1;
1101         }
1102         return 0;
1103 }
1104
1105 int validate_sp(unsigned long sp, struct task_struct *p,
1106                        unsigned long nbytes)
1107 {
1108         unsigned long stack_page = (unsigned long)task_stack_page(p);
1109
1110         if (sp >= stack_page + sizeof(struct thread_struct)
1111             && sp <= stack_page + THREAD_SIZE - nbytes)
1112                 return 1;
1113
1114         return valid_irq_stack(sp, p, nbytes);
1115 }
1116
1117 EXPORT_SYMBOL(validate_sp);
1118
1119 unsigned long get_wchan(struct task_struct *p)
1120 {
1121         unsigned long ip, sp;
1122         int count = 0;
1123
1124         if (!p || p == current || p->state == TASK_RUNNING)
1125                 return 0;
1126
1127         sp = p->thread.ksp;
1128         if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1129                 return 0;
1130
1131         do {
1132                 sp = *(unsigned long *)sp;
1133                 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1134                         return 0;
1135                 if (count > 0) {
1136                         ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1137                         if (!in_sched_functions(ip))
1138                                 return ip;
1139                 }
1140         } while (count++ < 16);
1141         return 0;
1142 }
1143
1144 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1145
1146 void show_stack(struct task_struct *tsk, unsigned long *stack)
1147 {
1148         unsigned long sp, ip, lr, newsp;
1149         int count = 0;
1150         int firstframe = 1;
1151 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1152         int curr_frame = current->curr_ret_stack;
1153         extern void return_to_handler(void);
1154         unsigned long rth = (unsigned long)return_to_handler;
1155         unsigned long mrth = -1;
1156 #ifdef CONFIG_PPC64
1157         extern void mod_return_to_handler(void);
1158         rth = *(unsigned long *)rth;
1159         mrth = (unsigned long)mod_return_to_handler;
1160         mrth = *(unsigned long *)mrth;
1161 #endif
1162 #endif
1163
1164         sp = (unsigned long) stack;
1165         if (tsk == NULL)
1166                 tsk = current;
1167         if (sp == 0) {
1168                 if (tsk == current)
1169                         asm("mr %0,1" : "=r" (sp));
1170                 else
1171                         sp = tsk->thread.ksp;
1172         }
1173
1174         lr = 0;
1175         printk("Call Trace:\n");
1176         do {
1177                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1178                         return;
1179
1180                 stack = (unsigned long *) sp;
1181                 newsp = stack[0];
1182                 ip = stack[STACK_FRAME_LR_SAVE];
1183                 if (!firstframe || ip != lr) {
1184                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1185 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1186                         if ((ip == rth || ip == mrth) && curr_frame >= 0) {
1187                                 printk(" (%pS)",
1188                                        (void *)current->ret_stack[curr_frame].ret);
1189                                 curr_frame--;
1190                         }
1191 #endif
1192                         if (firstframe)
1193                                 printk(" (unreliable)");
1194                         printk("\n");
1195                 }
1196                 firstframe = 0;
1197
1198                 /*
1199                  * See if this is an exception frame.
1200                  * We look for the "regshere" marker in the current frame.
1201                  */
1202                 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1203                     && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1204                         struct pt_regs *regs = (struct pt_regs *)
1205                                 (sp + STACK_FRAME_OVERHEAD);
1206                         lr = regs->link;
1207                         printk("--- Exception: %lx at %pS\n    LR = %pS\n",
1208                                regs->trap, (void *)regs->nip, (void *)lr);
1209                         firstframe = 1;
1210                 }
1211
1212                 sp = newsp;
1213         } while (count++ < kstack_depth_to_print);
1214 }
1215
1216 void dump_stack(void)
1217 {
1218         show_stack(current, NULL);
1219 }
1220 EXPORT_SYMBOL(dump_stack);
1221
1222 #ifdef CONFIG_PPC64
1223 /* Called with hard IRQs off */
1224 void __ppc64_runlatch_on(void)
1225 {
1226         struct thread_info *ti = current_thread_info();
1227         unsigned long ctrl;
1228
1229         ctrl = mfspr(SPRN_CTRLF);
1230         ctrl |= CTRL_RUNLATCH;
1231         mtspr(SPRN_CTRLT, ctrl);
1232
1233         ti->local_flags |= _TLF_RUNLATCH;
1234 }
1235
1236 /* Called with hard IRQs off */
1237 void __ppc64_runlatch_off(void)
1238 {
1239         struct thread_info *ti = current_thread_info();
1240         unsigned long ctrl;
1241
1242         ti->local_flags &= ~_TLF_RUNLATCH;
1243
1244         ctrl = mfspr(SPRN_CTRLF);
1245         ctrl &= ~CTRL_RUNLATCH;
1246         mtspr(SPRN_CTRLT, ctrl);
1247 }
1248 #endif /* CONFIG_PPC64 */
1249
1250 unsigned long arch_align_stack(unsigned long sp)
1251 {
1252         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
1253                 sp -= get_random_int() & ~PAGE_MASK;
1254         return sp & ~0xf;
1255 }
1256
1257 static inline unsigned long brk_rnd(void)
1258 {
1259         unsigned long rnd = 0;
1260
1261         /* 8MB for 32bit, 1GB for 64bit */
1262         if (is_32bit_task())
1263                 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
1264         else
1265                 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
1266
1267         return rnd << PAGE_SHIFT;
1268 }
1269
1270 unsigned long arch_randomize_brk(struct mm_struct *mm)
1271 {
1272         unsigned long base = mm->brk;
1273         unsigned long ret;
1274
1275 #ifdef CONFIG_PPC_STD_MMU_64
1276         /*
1277          * If we are using 1TB segments and we are allowed to randomise
1278          * the heap, we can put it above 1TB so it is backed by a 1TB
1279          * segment. Otherwise the heap will be in the bottom 1TB
1280          * which always uses 256MB segments and this may result in a
1281          * performance penalty.
1282          */
1283         if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
1284                 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
1285 #endif
1286
1287         ret = PAGE_ALIGN(base + brk_rnd());
1288
1289         if (ret < mm->brk)
1290                 return mm->brk;
1291
1292         return ret;
1293 }
1294
1295 unsigned long randomize_et_dyn(unsigned long base)
1296 {
1297         unsigned long ret = PAGE_ALIGN(base + brk_rnd());
1298
1299         if (ret < base)
1300                 return base;
1301
1302         return ret;
1303 }