arch/powerpc/kernel/process.c

   1 /*
   2  *  Derived from "arch/i386/kernel/process.c"
   3  *    Copyright (C) 1995  Linus Torvalds
   4  *
   5  *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
   6  *  Paul Mackerras (paulus@cs.anu.edu.au)
   7  *
   8  *  PowerPC version
   9  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
  10  *
  11  *  This program is free software; you can redistribute it and/or
  12  *  modify it under the terms of the GNU General Public License
  13  *  as published by the Free Software Foundation; either version
  14  *  2 of the License, or (at your option) any later version.
  15  */
  16
  17 #include <linux/errno.h>
  18 #include <linux/sched.h>
  19 #include <linux/kernel.h>
  20 #include <linux/mm.h>
  21 #include <linux/smp.h>
  22 #include <linux/stddef.h>
  23 #include <linux/unistd.h>
  24 #include <linux/ptrace.h>
  25 #include <linux/slab.h>
  26 #include <linux/user.h>
  27 #include <linux/elf.h>
  28 #include <linux/init.h>
  29 #include <linux/prctl.h>
  30 #include <linux/init_task.h>
  31 #include <linux/module.h>
  32 #include <linux/kallsyms.h>
  33 #include <linux/mqueue.h>
  34 #include <linux/hardirq.h>
  35 #include <linux/utsname.h>
  36 #include <linux/ftrace.h>
  37 #include <linux/kernel_stat.h>
  38 #include <linux/personality.h>
  39 #include <linux/random.h>
  40 #include <linux/hw_breakpoint.h>
  41
  42 #include <asm/pgtable.h>
  43 #include <asm/uaccess.h>
  44 #include <asm/system.h>
  45 #include <asm/io.h>
  46 #include <asm/processor.h>
  47 #include <asm/mmu.h>
  48 #include <asm/prom.h>
  49 #include <asm/machdep.h>
  50 #include <asm/time.h>
  51 #include <asm/syscalls.h>
  52 #ifdef CONFIG_PPC64
  53 #include <asm/firmware.h>
  54 #endif
  55 #include <linux/kprobes.h>
  56 #include <linux/kdebug.h>
  57
  58 extern unsigned long _get_SP(void);
  59
  60 #ifndef CONFIG_SMP
  61 struct task_struct *last_task_used_math = NULL;
  62 struct task_struct *last_task_used_altivec = NULL;
  63 struct task_struct *last_task_used_vsx = NULL;
  64 struct task_struct *last_task_used_spe = NULL;
  65 #endif
  66
  67 /*
  68  * Make sure the floating-point register state in the
  69  * the thread_struct is up to date for task tsk.
  70  */
  71 void flush_fp_to_thread(struct task_struct *tsk)
  72 {
  73         if (tsk->thread.regs) {
  74                 /*
  75                  * We need to disable preemption here because if we didn't,
  76                  * another process could get scheduled after the regs->msr
  77                  * test but before we have finished saving the FP registers
  78                  * to the thread_struct.  That process could take over the
  79                  * FPU, and then when we get scheduled again we would store
  80                  * bogus values for the remaining FP registers.
  81                  */
  82                 preempt_disable();
  83                 if (tsk->thread.regs->msr & MSR_FP) {
  84 #ifdef CONFIG_SMP
  85                         /*
  86                          * This should only ever be called for current or
  87                          * for a stopped child process.  Since we save away
  88                          * the FP register state on context switch on SMP,
  89                          * there is something wrong if a stopped child appears
  90                          * to still have its FP state in the CPU registers.
  91                          */
  92                         BUG_ON(tsk != current);
  93 #endif
  94                         giveup_fpu(tsk);
  95                 }
  96                 preempt_enable();
  97         }
  98 }
  99
 100 void enable_kernel_fp(void)
 101 {
 102         WARN_ON(preemptible());
 103
 104 #ifdef CONFIG_SMP
 105         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 106                 giveup_fpu(current);
 107         else
 108                 giveup_fpu(NULL);       /* just enables FP for kernel */
 109 #else
 110         giveup_fpu(last_task_used_math);
 111 #endif /* CONFIG_SMP */
 112 }
 113 EXPORT_SYMBOL(enable_kernel_fp);
 114
 115 #ifdef CONFIG_ALTIVEC
 116 void enable_kernel_altivec(void)
 117 {
 118         WARN_ON(preemptible());
 119
 120 #ifdef CONFIG_SMP
 121         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 122                 giveup_altivec(current);
 123         else
 124                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
 125 #else
 126         giveup_altivec(last_task_used_altivec);
 127 #endif /* CONFIG_SMP */
 128 }
 129 EXPORT_SYMBOL(enable_kernel_altivec);
 130
 131 /*
 132  * Make sure the VMX/Altivec register state in the
 133  * the thread_struct is up to date for task tsk.
 134  */
 135 void flush_altivec_to_thread(struct task_struct *tsk)
 136 {
 137         if (tsk->thread.regs) {
 138                 preempt_disable();
 139                 if (tsk->thread.regs->msr & MSR_VEC) {
 140 #ifdef CONFIG_SMP
 141                         BUG_ON(tsk != current);
 142 #endif
 143                         giveup_altivec(tsk);
 144                 }
 145                 preempt_enable();
 146         }
 147 }
 148 #endif /* CONFIG_ALTIVEC */
 149
 150 #ifdef CONFIG_VSX
 151 #if 0
 152 /* not currently used, but some crazy RAID module might want to later */
 153 void enable_kernel_vsx(void)
 154 {
 155         WARN_ON(preemptible());
 156
 157 #ifdef CONFIG_SMP
 158         if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
 159                 giveup_vsx(current);
 160         else
 161                 giveup_vsx(NULL);       /* just enable vsx for kernel - force */
 162 #else
 163         giveup_vsx(last_task_used_vsx);
 164 #endif /* CONFIG_SMP */
 165 }
 166 EXPORT_SYMBOL(enable_kernel_vsx);
 167 #endif
 168
 169 void giveup_vsx(struct task_struct *tsk)
 170 {
 171         giveup_fpu(tsk);
 172         giveup_altivec(tsk);
 173         __giveup_vsx(tsk);
 174 }
 175
 176 void flush_vsx_to_thread(struct task_struct *tsk)
 177 {
 178         if (tsk->thread.regs) {
 179                 preempt_disable();
 180                 if (tsk->thread.regs->msr & MSR_VSX) {
 181 #ifdef CONFIG_SMP
 182                         BUG_ON(tsk != current);
 183 #endif
 184                         giveup_vsx(tsk);
 185                 }
 186                 preempt_enable();
 187         }
 188 }
 189 #endif /* CONFIG_VSX */
 190
 191 #ifdef CONFIG_SPE
 192
 193 void enable_kernel_spe(void)
 194 {
 195         WARN_ON(preemptible());
 196
 197 #ifdef CONFIG_SMP
 198         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 199                 giveup_spe(current);
 200         else
 201                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 202 #else
 203         giveup_spe(last_task_used_spe);
 204 #endif /* __SMP __ */
 205 }
 206 EXPORT_SYMBOL(enable_kernel_spe);
 207
 208 void flush_spe_to_thread(struct task_struct *tsk)
 209 {
 210         if (tsk->thread.regs) {
 211                 preempt_disable();
 212                 if (tsk->thread.regs->msr & MSR_SPE) {
 213 #ifdef CONFIG_SMP
 214                         BUG_ON(tsk != current);
 215 #endif
 216                         giveup_spe(tsk);
 217                 }
 218                 preempt_enable();
 219         }
 220 }
 221 #endif /* CONFIG_SPE */
 222
 223 #ifndef CONFIG_SMP
 224 /*
 225  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 226  * and the current task has some state, discard it.
 227  */
 228 void discard_lazy_cpu_state(void)
 229 {
 230         preempt_disable();
 231         if (last_task_used_math == current)
 232                 last_task_used_math = NULL;
 233 #ifdef CONFIG_ALTIVEC
 234         if (last_task_used_altivec == current)
 235                 last_task_used_altivec = NULL;
 236 #endif /* CONFIG_ALTIVEC */
 237 #ifdef CONFIG_VSX
 238         if (last_task_used_vsx == current)
 239                 last_task_used_vsx = NULL;
 240 #endif /* CONFIG_VSX */
 241 #ifdef CONFIG_SPE
 242         if (last_task_used_spe == current)
 243                 last_task_used_spe = NULL;
 244 #endif
 245         preempt_enable();
 246 }
 247 #endif /* CONFIG_SMP */
 248
 249 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 250 void do_send_trap(struct pt_regs *regs, unsigned long address,
 251                   unsigned long error_code, int signal_code, int breakpt)
 252 {
 253         siginfo_t info;
 254
 255         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 256                         11, SIGSEGV) == NOTIFY_STOP)
 257                 return;
 258
 259         /* Deliver the signal to userspace */
 260         info.si_signo = SIGTRAP;
 261         info.si_errno = breakpt;        /* breakpoint or watchpoint id */
 262         info.si_code = signal_code;
 263         info.si_addr = (void __user *)address;
 264         force_sig_info(SIGTRAP, &info, current);
 265 }
 266 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
 267 void do_dabr(struct pt_regs *regs, unsigned long address,
 268                     unsigned long error_code)
 269 {
 270         siginfo_t info;
 271
 272         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 273                         11, SIGSEGV) == NOTIFY_STOP)
 274                 return;
 275
 276         if (debugger_dabr_match(regs))
 277                 return;
 278
 279         /* Clear the DABR */
 280         set_dabr(0);
 281
 282         /* Deliver the signal to userspace */
 283         info.si_signo = SIGTRAP;
 284         info.si_errno = 0;
 285         info.si_code = TRAP_HWBKPT;
 286         info.si_addr = (void __user *)address;
 287         force_sig_info(SIGTRAP, &info, current);
 288 }
 289 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
 290
 291 static DEFINE_PER_CPU(unsigned long, current_dabr);
 292
 293 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 294 /*
 295  * Set the debug registers back to their default "safe" values.
 296  */
 297 static void set_debug_reg_defaults(struct thread_struct *thread)
 298 {
 299         thread->iac1 = thread->iac2 = 0;
 300 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 301         thread->iac3 = thread->iac4 = 0;
 302 #endif
 303         thread->dac1 = thread->dac2 = 0;
 304 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 305         thread->dvc1 = thread->dvc2 = 0;
 306 #endif
 307         thread->dbcr0 = 0;
 308 #ifdef CONFIG_BOOKE
 309         /*
 310          * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
 311          */
 312         thread->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |   \
 313                         DBCR1_IAC3US | DBCR1_IAC4US;
 314         /*
 315          * Force Data Address Compare User/Supervisor bits to be User-only
 316          * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
 317          */
 318         thread->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
 319 #else
 320         thread->dbcr1 = 0;
 321 #endif
 322 }
 323
 324 static void prime_debug_regs(struct thread_struct *thread)
 325 {
 326         mtspr(SPRN_IAC1, thread->iac1);
 327         mtspr(SPRN_IAC2, thread->iac2);
 328 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 329         mtspr(SPRN_IAC3, thread->iac3);
 330         mtspr(SPRN_IAC4, thread->iac4);
 331 #endif
 332         mtspr(SPRN_DAC1, thread->dac1);
 333         mtspr(SPRN_DAC2, thread->dac2);
 334 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 335         mtspr(SPRN_DVC1, thread->dvc1);
 336         mtspr(SPRN_DVC2, thread->dvc2);
 337 #endif
 338         mtspr(SPRN_DBCR0, thread->dbcr0);
 339         mtspr(SPRN_DBCR1, thread->dbcr1);
 340 #ifdef CONFIG_BOOKE
 341         mtspr(SPRN_DBCR2, thread->dbcr2);
 342 #endif
 343 }
 344 /*
 345  * Unless neither the old or new thread are making use of the
 346  * debug registers, set the debug registers from the values
 347  * stored in the new thread.
 348  */
 349 static void switch_booke_debug_regs(struct thread_struct *new_thread)
 350 {
 351         if ((current->thread.dbcr0 & DBCR0_IDM)
 352                 || (new_thread->dbcr0 & DBCR0_IDM))
 353                         prime_debug_regs(new_thread);
 354 }
 355 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
 356 #ifndef CONFIG_HAVE_HW_BREAKPOINT
 357 static void set_debug_reg_defaults(struct thread_struct *thread)
 358 {
 359         if (thread->dabr) {
 360                 thread->dabr = 0;
 361                 set_dabr(0);
 362         }
 363 }
 364 #endif /* !CONFIG_HAVE_HW_BREAKPOINT */
 365 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
 366
 367 int set_dabr(unsigned long dabr)
 368 {
 369         __get_cpu_var(current_dabr) = dabr;
 370
 371         if (ppc_md.set_dabr)
 372                 return ppc_md.set_dabr(dabr);
 373
 374         /* XXX should we have a CPU_FTR_HAS_DABR ? */
 375 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 376         mtspr(SPRN_DAC1, dabr);
 377 #ifdef CONFIG_PPC_47x
 378         isync();
 379 #endif
 380 #elif defined(CONFIG_PPC_BOOK3S)
 381         mtspr(SPRN_DABR, dabr);
 382 #endif
 383
 384
 385         return 0;
 386 }
 387
 388 #ifdef CONFIG_PPC64
 389 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 390 #endif
 391
 392 struct task_struct *__switch_to(struct task_struct *prev,
 393         struct task_struct *new)
 394 {
 395         struct thread_struct *new_thread, *old_thread;
 396         unsigned long flags;
 397         struct task_struct *last;
 398
 399 #ifdef CONFIG_SMP
 400         /* avoid complexity of lazy save/restore of fpu
 401          * by just saving it every time we switch out if
 402          * this task used the fpu during the last quantum.
 403          *
 404          * If it tries to use the fpu again, it'll trap and
 405          * reload its fp regs.  So we don't have to do a restore
 406          * every switch, just a save.
 407          *  -- Cort
 408          */
 409         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 410                 giveup_fpu(prev);
 411 #ifdef CONFIG_ALTIVEC
 412         /*
 413          * If the previous thread used altivec in the last quantum
 414          * (thus changing altivec regs) then save them.
 415          * We used to check the VRSAVE register but not all apps
 416          * set it, so we don't rely on it now (and in fact we need
 417          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 418          *
 419          * On SMP we always save/restore altivec regs just to avoid the
 420          * complexity of changing processors.
 421          *  -- Cort
 422          */
 423         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 424                 giveup_altivec(prev);
 425 #endif /* CONFIG_ALTIVEC */
 426 #ifdef CONFIG_VSX
 427         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
 428                 /* VMX and FPU registers are already save here */
 429                 __giveup_vsx(prev);
 430 #endif /* CONFIG_VSX */
 431 #ifdef CONFIG_SPE
 432         /*
 433          * If the previous thread used spe in the last quantum
 434          * (thus changing spe regs) then save them.
 435          *
 436          * On SMP we always save/restore spe regs just to avoid the
 437          * complexity of changing processors.
 438          */
 439         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 440                 giveup_spe(prev);
 441 #endif /* CONFIG_SPE */
 442
 443 #else  /* CONFIG_SMP */
 444 #ifdef CONFIG_ALTIVEC
 445         /* Avoid the trap.  On smp this this never happens since
 446          * we don't set last_task_used_altivec -- Cort
 447          */
 448         if (new->thread.regs && last_task_used_altivec == new)
 449                 new->thread.regs->msr |= MSR_VEC;
 450 #endif /* CONFIG_ALTIVEC */
 451 #ifdef CONFIG_VSX
 452         if (new->thread.regs && last_task_used_vsx == new)
 453                 new->thread.regs->msr |= MSR_VSX;
 454 #endif /* CONFIG_VSX */
 455 #ifdef CONFIG_SPE
 456         /* Avoid the trap.  On smp this this never happens since
 457          * we don't set last_task_used_spe
 458          */
 459         if (new->thread.regs && last_task_used_spe == new)
 460                 new->thread.regs->msr |= MSR_SPE;
 461 #endif /* CONFIG_SPE */
 462
 463 #endif /* CONFIG_SMP */
 464
 465 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 466         switch_booke_debug_regs(&new->thread);
 467 #else
 468 /*
 469  * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
 470  * schedule DABR
 471  */
 472 #ifndef CONFIG_HAVE_HW_BREAKPOINT
 473         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
 474                 set_dabr(new->thread.dabr);
 475 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 476 #endif
 477
 478
 479         new_thread = &new->thread;
 480         old_thread = &current->thread;
 481
 482 #if defined(CONFIG_PPC_BOOK3E_64)
 483         /* XXX Current Book3E code doesn't deal with kernel side DBCR0,
 484          * we always hold the user values, so we set it now.
 485          *
 486          * However, we ensure the kernel MSR:DE is appropriately cleared too
 487          * to avoid spurrious single step exceptions in the kernel.
 488          *
 489          * This will have to change to merge with the ppc32 code at some point,
 490          * but I don't like much what ppc32 is doing today so there's some
 491          * thinking needed there
 492          */
 493         if ((new_thread->dbcr0 | old_thread->dbcr0) & DBCR0_IDM) {
 494                 u32 dbcr0;
 495
 496                 mtmsr(mfmsr() & ~MSR_DE);
 497                 isync();
 498                 dbcr0 = mfspr(SPRN_DBCR0);
 499                 dbcr0 = (dbcr0 & DBCR0_EDM) | new_thread->dbcr0;
 500                 mtspr(SPRN_DBCR0, dbcr0);
 501         }
 502 #endif /* CONFIG_PPC64_BOOK3E */
 503
 504 #ifdef CONFIG_PPC64
 505         /*
 506          * Collect processor utilization data per process
 507          */
 508         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 509                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 510                 long unsigned start_tb, current_tb;
 511                 start_tb = old_thread->start_tb;
 512                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 513                 old_thread->accum_tb += (current_tb - start_tb);
 514                 new_thread->start_tb = current_tb;
 515         }
 516 #endif
 517
 518         local_irq_save(flags);
 519
 520         account_system_vtime(current);
 521         account_process_vtime(current);
 522
 523         /*
 524          * We can't take a PMU exception inside _switch() since there is a
 525          * window where the kernel stack SLB and the kernel stack are out
 526          * of sync. Hard disable here.
 527          */
 528         hard_irq_disable();
 529         last = _switch(old_thread, new_thread);
 530
 531         local_irq_restore(flags);
 532
 533         return last;
 534 }
 535
 536 static int instructions_to_print = 16;
 537
 538 static void show_instructions(struct pt_regs *regs)
 539 {
 540         int i;
 541         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 542                         sizeof(int));
 543
 544         printk("Instruction dump:");
 545
 546         for (i = 0; i < instructions_to_print; i++) {
 547                 int instr;
 548
 549                 if (!(i % 8))
 550                         printk("\n");
 551
 552 #if !defined(CONFIG_BOOKE)
 553                 /* If executing with the IMMU off, adjust pc rather
 554                  * than print XXXXXXXX.
 555                  */
 556                 if (!(regs->msr & MSR_IR))
 557                         pc = (unsigned long)phys_to_virt(pc);
 558 #endif
 559
 560                 /* We use __get_user here *only* to avoid an OOPS on a
 561                  * bad address because the pc *should* only be a
 562                  * kernel address.
 563                  */
 564                 if (!__kernel_text_address(pc) ||
 565                      __get_user(instr, (unsigned int __user *)pc)) {
 566                         printk("XXXXXXXX ");
 567                 } else {
 568                         if (regs->nip == pc)
 569                                 printk("<%08x> ", instr);
 570                         else
 571                                 printk("%08x ", instr);
 572                 }
 573
 574                 pc += sizeof(int);
 575         }
 576
 577         printk("\n");
 578 }
 579
 580 static struct regbit {
 581         unsigned long bit;
 582         const char *name;
 583 } msr_bits[] = {
 584         {MSR_EE,        "EE"},
 585         {MSR_PR,        "PR"},
 586         {MSR_FP,        "FP"},
 587         {MSR_VEC,       "VEC"},
 588         {MSR_VSX,       "VSX"},
 589         {MSR_ME,        "ME"},
 590         {MSR_CE,        "CE"},
 591         {MSR_DE,        "DE"},
 592         {MSR_IR,        "IR"},
 593         {MSR_DR,        "DR"},
 594         {0,             NULL}
 595 };
 596
 597 static void printbits(unsigned long val, struct regbit *bits)
 598 {
 599         const char *sep = "";
 600
 601         printk("<");
 602         for (; bits->bit; ++bits)
 603                 if (val & bits->bit) {
 604                         printk("%s%s", sep, bits->name);
 605                         sep = ",";
 606                 }
 607         printk(">");
 608 }
 609
 610 #ifdef CONFIG_PPC64
 611 #define REG             "%016lx"
 612 #define REGS_PER_LINE   4
 613 #define LAST_VOLATILE   13
 614 #else
 615 #define REG             "%08lx"
 616 #define REGS_PER_LINE   8
 617 #define LAST_VOLATILE   12
 618 #endif
 619
 620 void show_regs(struct pt_regs * regs)
 621 {
 622         int i, trap;
 623
 624         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 625                regs->nip, regs->link, regs->ctr);
 626         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 627                regs, regs->trap, print_tainted(), init_utsname()->release);
 628         printk("MSR: "REG" ", regs->msr);
 629         printbits(regs->msr, msr_bits);
 630         printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
 631         trap = TRAP(regs);
 632         if (trap == 0x300 || trap == 0x600)
 633 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 634                 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
 635 #else
 636                 printk("DAR: "REG", DSISR: %08lx\n", regs->dar, regs->dsisr);
 637 #endif
 638         printk("TASK = %p[%d] '%s' THREAD: %p",
 639                current, task_pid_nr(current), current->comm, task_thread_info(current));
 640
 641 #ifdef CONFIG_SMP
 642         printk(" CPU: %d", raw_smp_processor_id());
 643 #endif /* CONFIG_SMP */
 644
 645         for (i = 0;  i < 32;  i++) {
 646                 if ((i % REGS_PER_LINE) == 0)
 647                         printk("\nGPR%02d: ", i);
 648                 printk(REG " ", regs->gpr[i]);
 649                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
 650                         break;
 651         }
 652         printk("\n");
 653 #ifdef CONFIG_KALLSYMS
 654         /*
 655          * Lookup NIP late so we have the best change of getting the
 656          * above info out without failing
 657          */
 658         printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
 659         printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
 660 #endif
 661         show_stack(current, (unsigned long *) regs->gpr[1]);
 662         if (!user_mode(regs))
 663                 show_instructions(regs);
 664 }
 665
 666 void exit_thread(void)
 667 {
 668         discard_lazy_cpu_state();
 669 }
 670
 671 void flush_thread(void)
 672 {
 673         discard_lazy_cpu_state();
 674
 675 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 676         flush_ptrace_hw_breakpoint(current);
 677 #else /* CONFIG_HAVE_HW_BREAKPOINT */
 678         set_debug_reg_defaults(&current->thread);
 679 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 680 }
 681
 682 void
 683 release_thread(struct task_struct *t)
 684 {
 685 }
 686
 687 /*
 688  * This gets called before we allocate a new thread and copy
 689  * the current task into it.
 690  */
 691 void prepare_to_copy(struct task_struct *tsk)
 692 {
 693         flush_fp_to_thread(current);
 694         flush_altivec_to_thread(current);
 695         flush_vsx_to_thread(current);
 696         flush_spe_to_thread(current);
 697 #ifdef CONFIG_HAVE_HW_BREAKPOINT
 698         flush_ptrace_hw_breakpoint(tsk);
 699 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 700 }
 701
 702 /*
 703  * Copy a thread..
 704  */
 705 extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
 706
 707 int copy_thread(unsigned long clone_flags, unsigned long usp,
 708                 unsigned long unused, struct task_struct *p,
 709                 struct pt_regs *regs)
 710 {
 711         struct pt_regs *childregs, *kregs;
 712         extern void ret_from_fork(void);
 713         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
 714
 715         CHECK_FULL_REGS(regs);
 716         /* Copy registers */
 717         sp -= sizeof(struct pt_regs);
 718         childregs = (struct pt_regs *) sp;
 719         *childregs = *regs;
 720         if ((childregs->msr & MSR_PR) == 0) {
 721                 /* for kernel thread, set `current' and stackptr in new task */
 722                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
 723 #ifdef CONFIG_PPC32
 724                 childregs->gpr[2] = (unsigned long) p;
 725 #else
 726                 clear_tsk_thread_flag(p, TIF_32BIT);
 727 #endif
 728                 p->thread.regs = NULL;  /* no user register state */
 729         } else {
 730                 childregs->gpr[1] = usp;
 731                 p->thread.regs = childregs;
 732                 if (clone_flags & CLONE_SETTLS) {
 733 #ifdef CONFIG_PPC64
 734                         if (!is_32bit_task())
 735                                 childregs->gpr[13] = childregs->gpr[6];
 736                         else
 737 #endif
 738                                 childregs->gpr[2] = childregs->gpr[6];
 739                 }
 740         }
 741         childregs->gpr[3] = 0;  /* Result from fork() */
 742         sp -= STACK_FRAME_OVERHEAD;
 743
 744         /*
 745          * The way this works is that at some point in the future
 746          * some task will call _switch to switch to the new task.
 747          * That will pop off the stack frame created below and start
 748          * the new task running at ret_from_fork.  The new task will
 749          * do some house keeping and then return from the fork or clone
 750          * system call, using the stack frame created above.
 751          */
 752         sp -= sizeof(struct pt_regs);
 753         kregs = (struct pt_regs *) sp;
 754         sp -= STACK_FRAME_OVERHEAD;
 755         p->thread.ksp = sp;
 756         p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
 757                                 _ALIGN_UP(sizeof(struct thread_info), 16);
 758
 759 #ifdef CONFIG_PPC_STD_MMU_64
 760         if (mmu_has_feature(MMU_FTR_SLB)) {
 761                 unsigned long sp_vsid;
 762                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
 763
 764                 if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
 765                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
 766                                 << SLB_VSID_SHIFT_1T;
 767                 else
 768                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
 769                                 << SLB_VSID_SHIFT;
 770                 sp_vsid |= SLB_VSID_KERNEL | llp;
 771                 p->thread.ksp_vsid = sp_vsid;
 772         }
 773 #endif /* CONFIG_PPC_STD_MMU_64 */
 774 #ifdef CONFIG_PPC64
 775         if (cpu_has_feature(CPU_FTR_DSCR)) {
 776                 if (current->thread.dscr_inherit) {
 777                         p->thread.dscr_inherit = 1;
 778                         p->thread.dscr = current->thread.dscr;
 779                 } else if (0 != dscr_default) {
 780                         p->thread.dscr_inherit = 1;
 781                         p->thread.dscr = dscr_default;
 782                 } else {
 783                         p->thread.dscr_inherit = 0;
 784                         p->thread.dscr = 0;
 785                 }
 786         }
 787 #endif
 788
 789         /*
 790          * The PPC64 ABI makes use of a TOC to contain function
 791          * pointers.  The function (ret_from_except) is actually a pointer
 792          * to the TOC entry.  The first entry is a pointer to the actual
 793          * function.
 794          */
 795 #ifdef CONFIG_PPC64
 796         kregs->nip = *((unsigned long *)ret_from_fork);
 797 #else
 798         kregs->nip = (unsigned long)ret_from_fork;
 799 #endif
 800
 801         return 0;
 802 }
 803
 804 /*
 805  * Set up a thread for executing a new program
 806  */
 807 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
 808 {
 809 #ifdef CONFIG_PPC64
 810         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
 811 #endif
 812
 813         set_fs(USER_DS);
 814
 815         /*
 816          * If we exec out of a kernel thread then thread.regs will not be
 817          * set.  Do it now.
 818          */
 819         if (!current->thread.regs) {
 820                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
 821                 current->thread.regs = regs - 1;
 822         }
 823
 824         memset(regs->gpr, 0, sizeof(regs->gpr));
 825         regs->ctr = 0;
 826         regs->link = 0;
 827         regs->xer = 0;
 828         regs->ccr = 0;
 829         regs->gpr[1] = sp;
 830
 831         /*
 832          * We have just cleared all the nonvolatile GPRs, so make
 833          * FULL_REGS(regs) return true.  This is necessary to allow
 834          * ptrace to examine the thread immediately after exec.
 835          */
 836         regs->trap &= ~1UL;
 837
 838 #ifdef CONFIG_PPC32
 839         regs->mq = 0;
 840         regs->nip = start;
 841         regs->msr = MSR_USER;
 842 #else
 843         if (!is_32bit_task()) {
 844                 unsigned long entry, toc;
 845
 846                 /* start is a relocated pointer to the function descriptor for
 847                  * the elf _start routine.  The first entry in the function
 848                  * descriptor is the entry address of _start and the second
 849                  * entry is the TOC value we need to use.
 850                  */
 851                 __get_user(entry, (unsigned long __user *)start);
 852                 __get_user(toc, (unsigned long __user *)start+1);
 853
 854                 /* Check whether the e_entry function descriptor entries
 855                  * need to be relocated before we can use them.
 856                  */
 857                 if (load_addr != 0) {
 858                         entry += load_addr;
 859                         toc   += load_addr;
 860                 }
 861                 regs->nip = entry;
 862                 regs->gpr[2] = toc;
 863                 regs->msr = MSR_USER64;
 864         } else {
 865                 regs->nip = start;
 866                 regs->gpr[2] = 0;
 867                 regs->msr = MSR_USER32;
 868         }
 869 #endif
 870
 871         discard_lazy_cpu_state();
 872 #ifdef CONFIG_VSX
 873         current->thread.used_vsr = 0;
 874 #endif
 875         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
 876         current->thread.fpscr.val = 0;
 877 #ifdef CONFIG_ALTIVEC
 878         memset(current->thread.vr, 0, sizeof(current->thread.vr));
 879         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
 880         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
 881         current->thread.vrsave = 0;
 882         current->thread.used_vr = 0;
 883 #endif /* CONFIG_ALTIVEC */
 884 #ifdef CONFIG_SPE
 885         memset(current->thread.evr, 0, sizeof(current->thread.evr));
 886         current->thread.acc = 0;
 887         current->thread.spefscr = 0;
 888         current->thread.used_spe = 0;
 889 #endif /* CONFIG_SPE */
 890 }
 891
 892 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
 893                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
 894
 895 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
 896 {
 897         struct pt_regs *regs = tsk->thread.regs;
 898
 899         /* This is a bit hairy.  If we are an SPE enabled  processor
 900          * (have embedded fp) we store the IEEE exception enable flags in
 901          * fpexc_mode.  fpexc_mode is also used for setting FP exception
 902          * mode (asyn, precise, disabled) for 'Classic' FP. */
 903         if (val & PR_FP_EXC_SW_ENABLE) {
 904 #ifdef CONFIG_SPE
 905                 if (cpu_has_feature(CPU_FTR_SPE)) {
 906                         tsk->thread.fpexc_mode = val &
 907                                 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
 908                         return 0;
 909                 } else {
 910                         return -EINVAL;
 911                 }
 912 #else
 913                 return -EINVAL;
 914 #endif
 915         }
 916
 917         /* on a CONFIG_SPE this does not hurt us.  The bits that
 918          * __pack_fe01 use do not overlap with bits used for
 919          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
 920          * on CONFIG_SPE implementations are reserved so writing to
 921          * them does not change anything */
 922         if (val > PR_FP_EXC_PRECISE)
 923                 return -EINVAL;
 924         tsk->thread.fpexc_mode = __pack_fe01(val);
 925         if (regs != NULL && (regs->msr & MSR_FP) != 0)
 926                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
 927                         | tsk->thread.fpexc_mode;
 928         return 0;
 929 }
 930
 931 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
 932 {
 933         unsigned int val;
 934
 935         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
 936 #ifdef CONFIG_SPE
 937                 if (cpu_has_feature(CPU_FTR_SPE))
 938                         val = tsk->thread.fpexc_mode;
 939                 else
 940                         return -EINVAL;
 941 #else
 942                 return -EINVAL;
 943 #endif
 944         else
 945                 val = __unpack_fe01(tsk->thread.fpexc_mode);
 946         return put_user(val, (unsigned int __user *) adr);
 947 }
 948
 949 int set_endian(struct task_struct *tsk, unsigned int val)
 950 {
 951         struct pt_regs *regs = tsk->thread.regs;
 952
 953         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
 954             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
 955                 return -EINVAL;
 956
 957         if (regs == NULL)
 958                 return -EINVAL;
 959
 960         if (val == PR_ENDIAN_BIG)
 961                 regs->msr &= ~MSR_LE;
 962         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
 963                 regs->msr |= MSR_LE;
 964         else
 965                 return -EINVAL;
 966
 967         return 0;
 968 }
 969
 970 int get_endian(struct task_struct *tsk, unsigned long adr)
 971 {
 972         struct pt_regs *regs = tsk->thread.regs;
 973         unsigned int val;
 974
 975         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
 976             !cpu_has_feature(CPU_FTR_REAL_LE))
 977                 return -EINVAL;
 978
 979         if (regs == NULL)
 980                 return -EINVAL;
 981
 982         if (regs->msr & MSR_LE) {
 983                 if (cpu_has_feature(CPU_FTR_REAL_LE))
 984                         val = PR_ENDIAN_LITTLE;
 985                 else
 986                         val = PR_ENDIAN_PPC_LITTLE;
 987         } else
 988                 val = PR_ENDIAN_BIG;
 989
 990         return put_user(val, (unsigned int __user *)adr);
 991 }
 992
 993 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
 994 {
 995         tsk->thread.align_ctl = val;
 996         return 0;
 997 }
 998
 999 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
1000 {
1001         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
1002 }
1003
1004 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
1005
1006 int sys_clone(unsigned long clone_flags, unsigned long usp,
1007               int __user *parent_tidp, void __user *child_threadptr,
1008               int __user *child_tidp, int p6,
1009               struct pt_regs *regs)
1010 {
1011         CHECK_FULL_REGS(regs);
1012         if (usp == 0)
1013                 usp = regs->gpr[1];     /* stack pointer for child */
1014 #ifdef CONFIG_PPC64
1015         if (is_32bit_task()) {
1016                 parent_tidp = TRUNC_PTR(parent_tidp);
1017                 child_tidp = TRUNC_PTR(child_tidp);
1018         }
1019 #endif
1020         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
1021 }
1022
1023 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
1024              unsigned long p4, unsigned long p5, unsigned long p6,
1025              struct pt_regs *regs)
1026 {
1027         CHECK_FULL_REGS(regs);
1028         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
1029 }
1030
1031 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
1032               unsigned long p4, unsigned long p5, unsigned long p6,
1033               struct pt_regs *regs)
1034 {
1035         CHECK_FULL_REGS(regs);
1036         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
1037                         regs, 0, NULL, NULL);
1038 }
1039
1040 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
1041                unsigned long a3, unsigned long a4, unsigned long a5,
1042                struct pt_regs *regs)
1043 {
1044         int error;
1045         char *filename;
1046
1047         filename = getname((const char __user *) a0);
1048         error = PTR_ERR(filename);
1049         if (IS_ERR(filename))
1050                 goto out;
1051         flush_fp_to_thread(current);
1052         flush_altivec_to_thread(current);
1053         flush_spe_to_thread(current);
1054         error = do_execve(filename,
1055                           (const char __user *const __user *) a1,
1056                           (const char __user *const __user *) a2, regs);
1057         putname(filename);
1058 out:
1059         return error;
1060 }
1061
1062 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
1063                                   unsigned long nbytes)
1064 {
1065         unsigned long stack_page;
1066         unsigned long cpu = task_cpu(p);
1067
1068         /*
1069          * Avoid crashing if the stack has overflowed and corrupted
1070          * task_cpu(p), which is in the thread_info struct.
1071          */
1072         if (cpu < NR_CPUS && cpu_possible(cpu)) {
1073                 stack_page = (unsigned long) hardirq_ctx[cpu];
1074                 if (sp >= stack_page + sizeof(struct thread_struct)
1075                     && sp <= stack_page + THREAD_SIZE - nbytes)
1076                         return 1;
1077
1078                 stack_page = (unsigned long) softirq_ctx[cpu];
1079                 if (sp >= stack_page + sizeof(struct thread_struct)
1080                     && sp <= stack_page + THREAD_SIZE - nbytes)
1081                         return 1;
1082         }
1083         return 0;
1084 }
1085
1086 int validate_sp(unsigned long sp, struct task_struct *p,
1087                        unsigned long nbytes)
1088 {
1089         unsigned long stack_page = (unsigned long)task_stack_page(p);
1090
1091         if (sp >= stack_page + sizeof(struct thread_struct)
1092             && sp <= stack_page + THREAD_SIZE - nbytes)
1093                 return 1;
1094
1095         return valid_irq_stack(sp, p, nbytes);
1096 }
1097
1098 EXPORT_SYMBOL(validate_sp);
1099
1100 unsigned long get_wchan(struct task_struct *p)
1101 {
1102         unsigned long ip, sp;
1103         int count = 0;
1104
1105         if (!p || p == current || p->state == TASK_RUNNING)
1106                 return 0;
1107
1108         sp = p->thread.ksp;
1109         if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1110                 return 0;
1111
1112         do {
1113                 sp = *(unsigned long *)sp;
1114                 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1115                         return 0;
1116                 if (count > 0) {
1117                         ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1118                         if (!in_sched_functions(ip))
1119                                 return ip;
1120                 }
1121         } while (count++ < 16);
1122         return 0;
1123 }
1124
1125 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1126
1127 void show_stack(struct task_struct *tsk, unsigned long *stack)
1128 {
1129         unsigned long sp, ip, lr, newsp;
1130         int count = 0;
1131         int firstframe = 1;
1132 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1133         int curr_frame = current->curr_ret_stack;
1134         extern void return_to_handler(void);
1135         unsigned long rth = (unsigned long)return_to_handler;
1136         unsigned long mrth = -1;
1137 #ifdef CONFIG_PPC64
1138         extern void mod_return_to_handler(void);
1139         rth = *(unsigned long *)rth;
1140         mrth = (unsigned long)mod_return_to_handler;
1141         mrth = *(unsigned long *)mrth;
1142 #endif
1143 #endif
1144
1145         sp = (unsigned long) stack;
1146         if (tsk == NULL)
1147                 tsk = current;
1148         if (sp == 0) {
1149                 if (tsk == current)
1150                         asm("mr %0,1" : "=r" (sp));
1151                 else
1152                         sp = tsk->thread.ksp;
1153         }
1154
1155         lr = 0;
1156         printk("Call Trace:\n");
1157         do {
1158                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1159                         return;
1160
1161                 stack = (unsigned long *) sp;
1162                 newsp = stack[0];
1163                 ip = stack[STACK_FRAME_LR_SAVE];
1164                 if (!firstframe || ip != lr) {
1165                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1166 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1167                         if ((ip == rth || ip == mrth) && curr_frame >= 0) {
1168                                 printk(" (%pS)",
1169                                        (void *)current->ret_stack[curr_frame].ret);
1170                                 curr_frame--;
1171                         }
1172 #endif
1173                         if (firstframe)
1174                                 printk(" (unreliable)");
1175                         printk("\n");
1176                 }
1177                 firstframe = 0;
1178
1179                 /*
1180                  * See if this is an exception frame.
1181                  * We look for the "regshere" marker in the current frame.
1182                  */
1183                 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1184                     && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1185                         struct pt_regs *regs = (struct pt_regs *)
1186                                 (sp + STACK_FRAME_OVERHEAD);
1187                         lr = regs->link;
1188                         printk("--- Exception: %lx at %pS\n    LR = %pS\n",
1189                                regs->trap, (void *)regs->nip, (void *)lr);
1190                         firstframe = 1;
1191                 }
1192
1193                 sp = newsp;
1194         } while (count++ < kstack_depth_to_print);
1195 }
1196
1197 void dump_stack(void)
1198 {
1199         show_stack(current, NULL);
1200 }
1201 EXPORT_SYMBOL(dump_stack);
1202
1203 #ifdef CONFIG_PPC64
1204 void ppc64_runlatch_on(void)
1205 {
1206         unsigned long ctrl;
1207
1208         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
1209                 HMT_medium();
1210
1211                 ctrl = mfspr(SPRN_CTRLF);
1212                 ctrl |= CTRL_RUNLATCH;
1213                 mtspr(SPRN_CTRLT, ctrl);
1214
1215                 set_thread_flag(TIF_RUNLATCH);
1216         }
1217 }
1218
1219 void __ppc64_runlatch_off(void)
1220 {
1221         unsigned long ctrl;
1222
1223         HMT_medium();
1224
1225         clear_thread_flag(TIF_RUNLATCH);
1226
1227         ctrl = mfspr(SPRN_CTRLF);
1228         ctrl &= ~CTRL_RUNLATCH;
1229         mtspr(SPRN_CTRLT, ctrl);
1230 }
1231 #endif
1232
1233 #if THREAD_SHIFT < PAGE_SHIFT
1234
1235 static struct kmem_cache *thread_info_cache;
1236
1237 struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
1238 {
1239         struct thread_info *ti;
1240
1241         ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
1242         if (unlikely(ti == NULL))
1243                 return NULL;
1244 #ifdef CONFIG_DEBUG_STACK_USAGE
1245         memset(ti, 0, THREAD_SIZE);
1246 #endif
1247         return ti;
1248 }
1249
1250 void free_thread_info(struct thread_info *ti)
1251 {
1252         kmem_cache_free(thread_info_cache, ti);
1253 }
1254
1255 void thread_info_cache_init(void)
1256 {
1257         thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
1258                                               THREAD_SIZE, 0, NULL);
1259         BUG_ON(thread_info_cache == NULL);
1260 }
1261
1262 #endif /* THREAD_SHIFT < PAGE_SHIFT */
1263
1264 unsigned long arch_align_stack(unsigned long sp)
1265 {
1266         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
1267                 sp -= get_random_int() & ~PAGE_MASK;
1268         return sp & ~0xf;
1269 }
1270
1271 static inline unsigned long brk_rnd(void)
1272 {
1273         unsigned long rnd = 0;
1274
1275         /* 8MB for 32bit, 1GB for 64bit */
1276         if (is_32bit_task())
1277                 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
1278         else
1279                 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
1280
1281         return rnd << PAGE_SHIFT;
1282 }
1283
1284 unsigned long arch_randomize_brk(struct mm_struct *mm)
1285 {
1286         unsigned long base = mm->brk;
1287         unsigned long ret;
1288
1289 #ifdef CONFIG_PPC_STD_MMU_64
1290         /*
1291          * If we are using 1TB segments and we are allowed to randomise
1292          * the heap, we can put it above 1TB so it is backed by a 1TB
1293          * segment. Otherwise the heap will be in the bottom 1TB
1294          * which always uses 256MB segments and this may result in a
1295          * performance penalty.
1296          */
1297         if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
1298                 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
1299 #endif
1300
1301         ret = PAGE_ALIGN(base + brk_rnd());
1302
1303         if (ret < mm->brk)
1304                 return mm->brk;
1305
1306         return ret;
1307 }
1308
1309 unsigned long randomize_et_dyn(unsigned long base)
1310 {
1311         unsigned long ret = PAGE_ALIGN(base + brk_rnd());
1312
1313         if (ret < base)
1314                 return base;
1315
1316         return ret;
1317 }