Pileus Git - ~andy/linux/blob - 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/prctl.h>
  29 #include <linux/init_task.h>
  30 #include <linux/export.h>
  31 #include <linux/kallsyms.h>
  32 #include <linux/mqueue.h>
  33 #include <linux/hardirq.h>
  34 #include <linux/utsname.h>
  35 #include <linux/ftrace.h>
  36 #include <linux/kernel_stat.h>
  37 #include <linux/personality.h>
  38 #include <linux/random.h>
  39 #include <linux/hw_breakpoint.h>
  40
  41 #include <asm/pgtable.h>
  42 #include <asm/uaccess.h>
  43 #include <asm/io.h>
  44 #include <asm/processor.h>
  45 #include <asm/mmu.h>
  46 #include <asm/prom.h>
  47 #include <asm/machdep.h>
  48 #include <asm/time.h>
  49 #include <asm/runlatch.h>
  50 #include <asm/syscalls.h>
  51 #include <asm/switch_to.h>
  52 #include <asm/tm.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 /* Transactional Memory debug */
  61 #ifdef TM_DEBUG_SW
  62 #define TM_DEBUG(x...) printk(KERN_INFO x)
  63 #else
  64 #define TM_DEBUG(x...) do { } while(0)
  65 #endif
  66
  67 extern unsigned long _get_SP(void);
  68
  69 #ifndef CONFIG_SMP
  70 struct task_struct *last_task_used_math = NULL;
  71 struct task_struct *last_task_used_altivec = NULL;
  72 struct task_struct *last_task_used_vsx = NULL;
  73 struct task_struct *last_task_used_spe = NULL;
  74 #endif
  75
  76 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
  77 void giveup_fpu_maybe_transactional(struct task_struct *tsk)
  78 {
  79         /*
  80          * If we are saving the current thread's registers, and the
  81          * thread is in a transactional state, set the TIF_RESTORE_TM
  82          * bit so that we know to restore the registers before
  83          * returning to userspace.
  84          */
  85         if (tsk == current && tsk->thread.regs &&
  86             MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
  87             !test_thread_flag(TIF_RESTORE_TM)) {
  88                 tsk->thread.tm_orig_msr = tsk->thread.regs->msr;
  89                 set_thread_flag(TIF_RESTORE_TM);
  90         }
  91
  92         giveup_fpu(tsk);
  93 }
  94
  95 void giveup_altivec_maybe_transactional(struct task_struct *tsk)
  96 {
  97         /*
  98          * If we are saving the current thread's registers, and the
  99          * thread is in a transactional state, set the TIF_RESTORE_TM
 100          * bit so that we know to restore the registers before
 101          * returning to userspace.
 102          */
 103         if (tsk == current && tsk->thread.regs &&
 104             MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
 105             !test_thread_flag(TIF_RESTORE_TM)) {
 106                 tsk->thread.tm_orig_msr = tsk->thread.regs->msr;
 107                 set_thread_flag(TIF_RESTORE_TM);
 108         }
 109
 110         giveup_altivec(tsk);
 111 }
 112
 113 #else
 114 #define giveup_fpu_maybe_transactional(tsk)     giveup_fpu(tsk)
 115 #define giveup_altivec_maybe_transactional(tsk) giveup_altivec(tsk)
 116 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
 117
 118 #ifdef CONFIG_PPC_FPU
 119 /*
 120  * Make sure the floating-point register state in the
 121  * the thread_struct is up to date for task tsk.
 122  */
 123 void flush_fp_to_thread(struct task_struct *tsk)
 124 {
 125         if (tsk->thread.regs) {
 126                 /*
 127                  * We need to disable preemption here because if we didn't,
 128                  * another process could get scheduled after the regs->msr
 129                  * test but before we have finished saving the FP registers
 130                  * to the thread_struct.  That process could take over the
 131                  * FPU, and then when we get scheduled again we would store
 132                  * bogus values for the remaining FP registers.
 133                  */
 134                 preempt_disable();
 135                 if (tsk->thread.regs->msr & MSR_FP) {
 136 #ifdef CONFIG_SMP
 137                         /*
 138                          * This should only ever be called for current or
 139                          * for a stopped child process.  Since we save away
 140                          * the FP register state on context switch on SMP,
 141                          * there is something wrong if a stopped child appears
 142                          * to still have its FP state in the CPU registers.
 143                          */
 144                         BUG_ON(tsk != current);
 145 #endif
 146                         giveup_fpu_maybe_transactional(tsk);
 147                 }
 148                 preempt_enable();
 149         }
 150 }
 151 EXPORT_SYMBOL_GPL(flush_fp_to_thread);
 152 #endif /* CONFIG_PPC_FPU */
 153
 154 void enable_kernel_fp(void)
 155 {
 156         WARN_ON(preemptible());
 157
 158 #ifdef CONFIG_SMP
 159         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
 160                 giveup_fpu_maybe_transactional(current);
 161         else
 162                 giveup_fpu(NULL);       /* just enables FP for kernel */
 163 #else
 164         giveup_fpu_maybe_transactional(last_task_used_math);
 165 #endif /* CONFIG_SMP */
 166 }
 167 EXPORT_SYMBOL(enable_kernel_fp);
 168
 169 #ifdef CONFIG_ALTIVEC
 170 void enable_kernel_altivec(void)
 171 {
 172         WARN_ON(preemptible());
 173
 174 #ifdef CONFIG_SMP
 175         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
 176                 giveup_altivec_maybe_transactional(current);
 177         else
 178                 giveup_altivec_notask();
 179 #else
 180         giveup_altivec_maybe_transactional(last_task_used_altivec);
 181 #endif /* CONFIG_SMP */
 182 }
 183 EXPORT_SYMBOL(enable_kernel_altivec);
 184
 185 /*
 186  * Make sure the VMX/Altivec register state in the
 187  * the thread_struct is up to date for task tsk.
 188  */
 189 void flush_altivec_to_thread(struct task_struct *tsk)
 190 {
 191         if (tsk->thread.regs) {
 192                 preempt_disable();
 193                 if (tsk->thread.regs->msr & MSR_VEC) {
 194 #ifdef CONFIG_SMP
 195                         BUG_ON(tsk != current);
 196 #endif
 197                         giveup_altivec_maybe_transactional(tsk);
 198                 }
 199                 preempt_enable();
 200         }
 201 }
 202 EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
 203 #endif /* CONFIG_ALTIVEC */
 204
 205 #ifdef CONFIG_VSX
 206 #if 0
 207 /* not currently used, but some crazy RAID module might want to later */
 208 void enable_kernel_vsx(void)
 209 {
 210         WARN_ON(preemptible());
 211
 212 #ifdef CONFIG_SMP
 213         if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
 214                 giveup_vsx(current);
 215         else
 216                 giveup_vsx(NULL);       /* just enable vsx for kernel - force */
 217 #else
 218         giveup_vsx(last_task_used_vsx);
 219 #endif /* CONFIG_SMP */
 220 }
 221 EXPORT_SYMBOL(enable_kernel_vsx);
 222 #endif
 223
 224 void giveup_vsx(struct task_struct *tsk)
 225 {
 226         giveup_fpu_maybe_transactional(tsk);
 227         giveup_altivec_maybe_transactional(tsk);
 228         __giveup_vsx(tsk);
 229 }
 230
 231 void flush_vsx_to_thread(struct task_struct *tsk)
 232 {
 233         if (tsk->thread.regs) {
 234                 preempt_disable();
 235                 if (tsk->thread.regs->msr & MSR_VSX) {
 236 #ifdef CONFIG_SMP
 237                         BUG_ON(tsk != current);
 238 #endif
 239                         giveup_vsx(tsk);
 240                 }
 241                 preempt_enable();
 242         }
 243 }
 244 EXPORT_SYMBOL_GPL(flush_vsx_to_thread);
 245 #endif /* CONFIG_VSX */
 246
 247 #ifdef CONFIG_SPE
 248
 249 void enable_kernel_spe(void)
 250 {
 251         WARN_ON(preemptible());
 252
 253 #ifdef CONFIG_SMP
 254         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
 255                 giveup_spe(current);
 256         else
 257                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
 258 #else
 259         giveup_spe(last_task_used_spe);
 260 #endif /* __SMP __ */
 261 }
 262 EXPORT_SYMBOL(enable_kernel_spe);
 263
 264 void flush_spe_to_thread(struct task_struct *tsk)
 265 {
 266         if (tsk->thread.regs) {
 267                 preempt_disable();
 268                 if (tsk->thread.regs->msr & MSR_SPE) {
 269 #ifdef CONFIG_SMP
 270                         BUG_ON(tsk != current);
 271 #endif
 272                         tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
 273                         giveup_spe(tsk);
 274                 }
 275                 preempt_enable();
 276         }
 277 }
 278 #endif /* CONFIG_SPE */
 279
 280 #ifndef CONFIG_SMP
 281 /*
 282  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
 283  * and the current task has some state, discard it.
 284  */
 285 void discard_lazy_cpu_state(void)
 286 {
 287         preempt_disable();
 288         if (last_task_used_math == current)
 289                 last_task_used_math = NULL;
 290 #ifdef CONFIG_ALTIVEC
 291         if (last_task_used_altivec == current)
 292                 last_task_used_altivec = NULL;
 293 #endif /* CONFIG_ALTIVEC */
 294 #ifdef CONFIG_VSX
 295         if (last_task_used_vsx == current)
 296                 last_task_used_vsx = NULL;
 297 #endif /* CONFIG_VSX */
 298 #ifdef CONFIG_SPE
 299         if (last_task_used_spe == current)
 300                 last_task_used_spe = NULL;
 301 #endif
 302         preempt_enable();
 303 }
 304 #endif /* CONFIG_SMP */
 305
 306 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 307 void do_send_trap(struct pt_regs *regs, unsigned long address,
 308                   unsigned long error_code, int signal_code, int breakpt)
 309 {
 310         siginfo_t info;
 311
 312         current->thread.trap_nr = signal_code;
 313         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 314                         11, SIGSEGV) == NOTIFY_STOP)
 315                 return;
 316
 317         /* Deliver the signal to userspace */
 318         info.si_signo = SIGTRAP;
 319         info.si_errno = breakpt;        /* breakpoint or watchpoint id */
 320         info.si_code = signal_code;
 321         info.si_addr = (void __user *)address;
 322         force_sig_info(SIGTRAP, &info, current);
 323 }
 324 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
 325 void do_break (struct pt_regs *regs, unsigned long address,
 326                     unsigned long error_code)
 327 {
 328         siginfo_t info;
 329
 330         current->thread.trap_nr = TRAP_HWBKPT;
 331         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
 332                         11, SIGSEGV) == NOTIFY_STOP)
 333                 return;
 334
 335         if (debugger_break_match(regs))
 336                 return;
 337
 338         /* Clear the breakpoint */
 339         hw_breakpoint_disable();
 340
 341         /* Deliver the signal to userspace */
 342         info.si_signo = SIGTRAP;
 343         info.si_errno = 0;
 344         info.si_code = TRAP_HWBKPT;
 345         info.si_addr = (void __user *)address;
 346         force_sig_info(SIGTRAP, &info, current);
 347 }
 348 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
 349
 350 static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk);
 351
 352 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 353 /*
 354  * Set the debug registers back to their default "safe" values.
 355  */
 356 static void set_debug_reg_defaults(struct thread_struct *thread)
 357 {
 358         thread->debug.iac1 = thread->debug.iac2 = 0;
 359 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 360         thread->debug.iac3 = thread->debug.iac4 = 0;
 361 #endif
 362         thread->debug.dac1 = thread->debug.dac2 = 0;
 363 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 364         thread->debug.dvc1 = thread->debug.dvc2 = 0;
 365 #endif
 366         thread->debug.dbcr0 = 0;
 367 #ifdef CONFIG_BOOKE
 368         /*
 369          * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
 370          */
 371         thread->debug.dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
 372                         DBCR1_IAC3US | DBCR1_IAC4US;
 373         /*
 374          * Force Data Address Compare User/Supervisor bits to be User-only
 375          * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
 376          */
 377         thread->debug.dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
 378 #else
 379         thread->debug.dbcr1 = 0;
 380 #endif
 381 }
 382
 383 static void prime_debug_regs(struct debug_reg *debug)
 384 {
 385         /*
 386          * We could have inherited MSR_DE from userspace, since
 387          * it doesn't get cleared on exception entry.  Make sure
 388          * MSR_DE is clear before we enable any debug events.
 389          */
 390         mtmsr(mfmsr() & ~MSR_DE);
 391
 392         mtspr(SPRN_IAC1, debug->iac1);
 393         mtspr(SPRN_IAC2, debug->iac2);
 394 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
 395         mtspr(SPRN_IAC3, debug->iac3);
 396         mtspr(SPRN_IAC4, debug->iac4);
 397 #endif
 398         mtspr(SPRN_DAC1, debug->dac1);
 399         mtspr(SPRN_DAC2, debug->dac2);
 400 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
 401         mtspr(SPRN_DVC1, debug->dvc1);
 402         mtspr(SPRN_DVC2, debug->dvc2);
 403 #endif
 404         mtspr(SPRN_DBCR0, debug->dbcr0);
 405         mtspr(SPRN_DBCR1, debug->dbcr1);
 406 #ifdef CONFIG_BOOKE
 407         mtspr(SPRN_DBCR2, debug->dbcr2);
 408 #endif
 409 }
 410 /*
 411  * Unless neither the old or new thread are making use of the
 412  * debug registers, set the debug registers from the values
 413  * stored in the new thread.
 414  */
 415 void switch_booke_debug_regs(struct debug_reg *new_debug)
 416 {
 417         if ((current->thread.debug.dbcr0 & DBCR0_IDM)
 418                 || (new_debug->dbcr0 & DBCR0_IDM))
 419                         prime_debug_regs(new_debug);
 420 }
 421 EXPORT_SYMBOL_GPL(switch_booke_debug_regs);
 422 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
 423 #ifndef CONFIG_HAVE_HW_BREAKPOINT
 424 static void set_debug_reg_defaults(struct thread_struct *thread)
 425 {
 426         thread->hw_brk.address = 0;
 427         thread->hw_brk.type = 0;
 428         set_breakpoint(&thread->hw_brk);
 429 }
 430 #endif /* !CONFIG_HAVE_HW_BREAKPOINT */
 431 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
 432
 433 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 434 static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
 435 {
 436         mtspr(SPRN_DAC1, dabr);
 437 #ifdef CONFIG_PPC_47x
 438         isync();
 439 #endif
 440         return 0;
 441 }
 442 #elif defined(CONFIG_PPC_BOOK3S)
 443 static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
 444 {
 445         mtspr(SPRN_DABR, dabr);
 446         if (cpu_has_feature(CPU_FTR_DABRX))
 447                 mtspr(SPRN_DABRX, dabrx);
 448         return 0;
 449 }
 450 #else
 451 static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
 452 {
 453         return -EINVAL;
 454 }
 455 #endif
 456
 457 static inline int set_dabr(struct arch_hw_breakpoint *brk)
 458 {
 459         unsigned long dabr, dabrx;
 460
 461         dabr = brk->address | (brk->type & HW_BRK_TYPE_DABR);
 462         dabrx = ((brk->type >> 3) & 0x7);
 463
 464         if (ppc_md.set_dabr)
 465                 return ppc_md.set_dabr(dabr, dabrx);
 466
 467         return __set_dabr(dabr, dabrx);
 468 }
 469
 470 static inline int set_dawr(struct arch_hw_breakpoint *brk)
 471 {
 472         unsigned long dawr, dawrx, mrd;
 473
 474         dawr = brk->address;
 475
 476         dawrx  = (brk->type & (HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE)) \
 477                                    << (63 - 58); //* read/write bits */
 478         dawrx |= ((brk->type & (HW_BRK_TYPE_TRANSLATE)) >> 2) \
 479                                    << (63 - 59); //* translate */
 480         dawrx |= (brk->type & (HW_BRK_TYPE_PRIV_ALL)) \
 481                                    >> 3; //* PRIM bits */
 482         /* dawr length is stored in field MDR bits 48:53.  Matches range in
 483            doublewords (64 bits) baised by -1 eg. 0b000000=1DW and
 484            0b111111=64DW.
 485            brk->len is in bytes.
 486            This aligns up to double word size, shifts and does the bias.
 487         */
 488         mrd = ((brk->len + 7) >> 3) - 1;
 489         dawrx |= (mrd & 0x3f) << (63 - 53);
 490
 491         if (ppc_md.set_dawr)
 492                 return ppc_md.set_dawr(dawr, dawrx);
 493         mtspr(SPRN_DAWR, dawr);
 494         mtspr(SPRN_DAWRX, dawrx);
 495         return 0;
 496 }
 497
 498 int set_breakpoint(struct arch_hw_breakpoint *brk)
 499 {
 500         __get_cpu_var(current_brk) = *brk;
 501
 502         if (cpu_has_feature(CPU_FTR_DAWR))
 503                 return set_dawr(brk);
 504
 505         return set_dabr(brk);
 506 }
 507
 508 #ifdef CONFIG_PPC64
 509 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
 510 #endif
 511
 512 static inline bool hw_brk_match(struct arch_hw_breakpoint *a,
 513                               struct arch_hw_breakpoint *b)
 514 {
 515         if (a->address != b->address)
 516                 return false;
 517         if (a->type != b->type)
 518                 return false;
 519         if (a->len != b->len)
 520                 return false;
 521         return true;
 522 }
 523
 524 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 525 static void tm_reclaim_thread(struct thread_struct *thr,
 526                               struct thread_info *ti, uint8_t cause)
 527 {
 528         unsigned long msr_diff = 0;
 529
 530         /*
 531          * If FP/VSX registers have been already saved to the
 532          * thread_struct, move them to the transact_fp array.
 533          * We clear the TIF_RESTORE_TM bit since after the reclaim
 534          * the thread will no longer be transactional.
 535          */
 536         if (test_ti_thread_flag(ti, TIF_RESTORE_TM)) {
 537                 msr_diff = thr->tm_orig_msr & ~thr->regs->msr;
 538                 if (msr_diff & MSR_FP)
 539                         memcpy(&thr->transact_fp, &thr->fp_state,
 540                                sizeof(struct thread_fp_state));
 541                 if (msr_diff & MSR_VEC)
 542                         memcpy(&thr->transact_vr, &thr->vr_state,
 543                                sizeof(struct thread_vr_state));
 544                 clear_ti_thread_flag(ti, TIF_RESTORE_TM);
 545                 msr_diff &= MSR_FP | MSR_VEC | MSR_VSX | MSR_FE0 | MSR_FE1;
 546         }
 547
 548         tm_reclaim(thr, thr->regs->msr, cause);
 549
 550         /* Having done the reclaim, we now have the checkpointed
 551          * FP/VSX values in the registers.  These might be valid
 552          * even if we have previously called enable_kernel_fp() or
 553          * flush_fp_to_thread(), so update thr->regs->msr to
 554          * indicate their current validity.
 555          */
 556         thr->regs->msr |= msr_diff;
 557 }
 558
 559 void tm_reclaim_current(uint8_t cause)
 560 {
 561         tm_enable();
 562         tm_reclaim_thread(&current->thread, current_thread_info(), cause);
 563 }
 564
 565 static inline void tm_reclaim_task(struct task_struct *tsk)
 566 {
 567         /* We have to work out if we're switching from/to a task that's in the
 568          * middle of a transaction.
 569          *
 570          * In switching we need to maintain a 2nd register state as
 571          * oldtask->thread.ckpt_regs.  We tm_reclaim(oldproc); this saves the
 572          * checkpointed (tbegin) state in ckpt_regs and saves the transactional
 573          * (current) FPRs into oldtask->thread.transact_fpr[].
 574          *
 575          * We also context switch (save) TFHAR/TEXASR/TFIAR in here.
 576          */
 577         struct thread_struct *thr = &tsk->thread;
 578
 579         if (!thr->regs)
 580                 return;
 581
 582         if (!MSR_TM_ACTIVE(thr->regs->msr))
 583                 goto out_and_saveregs;
 584
 585         /* Stash the original thread MSR, as giveup_fpu et al will
 586          * modify it.  We hold onto it to see whether the task used
 587          * FP & vector regs.  If the TIF_RESTORE_TM flag is set,
 588          * tm_orig_msr is already set.
 589          */
 590         if (!test_ti_thread_flag(task_thread_info(tsk), TIF_RESTORE_TM))
 591                 thr->tm_orig_msr = thr->regs->msr;
 592
 593         TM_DEBUG("--- tm_reclaim on pid %d (NIP=%lx, "
 594                  "ccr=%lx, msr=%lx, trap=%lx)\n",
 595                  tsk->pid, thr->regs->nip,
 596                  thr->regs->ccr, thr->regs->msr,
 597                  thr->regs->trap);
 598
 599         tm_reclaim_thread(thr, task_thread_info(tsk), TM_CAUSE_RESCHED);
 600
 601         TM_DEBUG("--- tm_reclaim on pid %d complete\n",
 602                  tsk->pid);
 603
 604 out_and_saveregs:
 605         /* Always save the regs here, even if a transaction's not active.
 606          * This context-switches a thread's TM info SPRs.  We do it here to
 607          * be consistent with the restore path (in recheckpoint) which
 608          * cannot happen later in _switch().
 609          */
 610         tm_save_sprs(thr);
 611 }
 612
 613 static inline void tm_recheckpoint_new_task(struct task_struct *new)
 614 {
 615         unsigned long msr;
 616
 617         if (!cpu_has_feature(CPU_FTR_TM))
 618                 return;
 619
 620         /* Recheckpoint the registers of the thread we're about to switch to.
 621          *
 622          * If the task was using FP, we non-lazily reload both the original and
 623          * the speculative FP register states.  This is because the kernel
 624          * doesn't see if/when a TM rollback occurs, so if we take an FP
 625          * unavoidable later, we are unable to determine which set of FP regs
 626          * need to be restored.
 627          */
 628         if (!new->thread.regs)
 629                 return;
 630
 631         /* The TM SPRs are restored here, so that TEXASR.FS can be set
 632          * before the trecheckpoint and no explosion occurs.
 633          */
 634         tm_restore_sprs(&new->thread);
 635
 636         if (!MSR_TM_ACTIVE(new->thread.regs->msr))
 637                 return;
 638         msr = new->thread.tm_orig_msr;
 639         /* Recheckpoint to restore original checkpointed register state. */
 640         TM_DEBUG("*** tm_recheckpoint of pid %d "
 641                  "(new->msr 0x%lx, new->origmsr 0x%lx)\n",
 642                  new->pid, new->thread.regs->msr, msr);
 643
 644         /* This loads the checkpointed FP/VEC state, if used */
 645         tm_recheckpoint(&new->thread, msr);
 646
 647         /* This loads the speculative FP/VEC state, if used */
 648         if (msr & MSR_FP) {
 649                 do_load_up_transact_fpu(&new->thread);
 650                 new->thread.regs->msr |=
 651                         (MSR_FP | new->thread.fpexc_mode);
 652         }
 653 #ifdef CONFIG_ALTIVEC
 654         if (msr & MSR_VEC) {
 655                 do_load_up_transact_altivec(&new->thread);
 656                 new->thread.regs->msr |= MSR_VEC;
 657         }
 658 #endif
 659         /* We may as well turn on VSX too since all the state is restored now */
 660         if (msr & MSR_VSX)
 661                 new->thread.regs->msr |= MSR_VSX;
 662
 663         TM_DEBUG("*** tm_recheckpoint of pid %d complete "
 664                  "(kernel msr 0x%lx)\n",
 665                  new->pid, mfmsr());
 666 }
 667
 668 static inline void __switch_to_tm(struct task_struct *prev)
 669 {
 670         if (cpu_has_feature(CPU_FTR_TM)) {
 671                 tm_enable();
 672                 tm_reclaim_task(prev);
 673         }
 674 }
 675
 676 /*
 677  * This is called if we are on the way out to userspace and the
 678  * TIF_RESTORE_TM flag is set.  It checks if we need to reload
 679  * FP and/or vector state and does so if necessary.
 680  * If userspace is inside a transaction (whether active or
 681  * suspended) and FP/VMX/VSX instructions have ever been enabled
 682  * inside that transaction, then we have to keep them enabled
 683  * and keep the FP/VMX/VSX state loaded while ever the transaction
 684  * continues.  The reason is that if we didn't, and subsequently
 685  * got a FP/VMX/VSX unavailable interrupt inside a transaction,
 686  * we don't know whether it's the same transaction, and thus we
 687  * don't know which of the checkpointed state and the transactional
 688  * state to use.
 689  */
 690 void restore_tm_state(struct pt_regs *regs)
 691 {
 692         unsigned long msr_diff;
 693
 694         clear_thread_flag(TIF_RESTORE_TM);
 695         if (!MSR_TM_ACTIVE(regs->msr))
 696                 return;
 697
 698         msr_diff = current->thread.tm_orig_msr & ~regs->msr;
 699         msr_diff &= MSR_FP | MSR_VEC | MSR_VSX;
 700         if (msr_diff & MSR_FP) {
 701                 fp_enable();
 702                 load_fp_state(&current->thread.fp_state);
 703                 regs->msr |= current->thread.fpexc_mode;
 704         }
 705         if (msr_diff & MSR_VEC) {
 706                 vec_enable();
 707                 load_vr_state(&current->thread.vr_state);
 708         }
 709         regs->msr |= msr_diff;
 710 }
 711
 712 #else
 713 #define tm_recheckpoint_new_task(new)
 714 #define __switch_to_tm(prev)
 715 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
 716
 717 struct task_struct *__switch_to(struct task_struct *prev,
 718         struct task_struct *new)
 719 {
 720         struct thread_struct *new_thread, *old_thread;
 721         struct task_struct *last;
 722 #ifdef CONFIG_PPC_BOOK3S_64
 723         struct ppc64_tlb_batch *batch;
 724 #endif
 725
 726         WARN_ON(!irqs_disabled());
 727
 728         /* Back up the TAR across context switches.
 729          * Note that the TAR is not available for use in the kernel.  (To
 730          * provide this, the TAR should be backed up/restored on exception
 731          * entry/exit instead, and be in pt_regs.  FIXME, this should be in
 732          * pt_regs anyway (for debug).)
 733          * Save the TAR here before we do treclaim/trecheckpoint as these
 734          * will change the TAR.
 735          */
 736         save_tar(&prev->thread);
 737
 738         __switch_to_tm(prev);
 739
 740 #ifdef CONFIG_SMP
 741         /* avoid complexity of lazy save/restore of fpu
 742          * by just saving it every time we switch out if
 743          * this task used the fpu during the last quantum.
 744          *
 745          * If it tries to use the fpu again, it'll trap and
 746          * reload its fp regs.  So we don't have to do a restore
 747          * every switch, just a save.
 748          *  -- Cort
 749          */
 750         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
 751                 giveup_fpu(prev);
 752 #ifdef CONFIG_ALTIVEC
 753         /*
 754          * If the previous thread used altivec in the last quantum
 755          * (thus changing altivec regs) then save them.
 756          * We used to check the VRSAVE register but not all apps
 757          * set it, so we don't rely on it now (and in fact we need
 758          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
 759          *
 760          * On SMP we always save/restore altivec regs just to avoid the
 761          * complexity of changing processors.
 762          *  -- Cort
 763          */
 764         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
 765                 giveup_altivec(prev);
 766 #endif /* CONFIG_ALTIVEC */
 767 #ifdef CONFIG_VSX
 768         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
 769                 /* VMX and FPU registers are already save here */
 770                 __giveup_vsx(prev);
 771 #endif /* CONFIG_VSX */
 772 #ifdef CONFIG_SPE
 773         /*
 774          * If the previous thread used spe in the last quantum
 775          * (thus changing spe regs) then save them.
 776          *
 777          * On SMP we always save/restore spe regs just to avoid the
 778          * complexity of changing processors.
 779          */
 780         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
 781                 giveup_spe(prev);
 782 #endif /* CONFIG_SPE */
 783
 784 #else  /* CONFIG_SMP */
 785 #ifdef CONFIG_ALTIVEC
 786         /* Avoid the trap.  On smp this this never happens since
 787          * we don't set last_task_used_altivec -- Cort
 788          */
 789         if (new->thread.regs && last_task_used_altivec == new)
 790                 new->thread.regs->msr |= MSR_VEC;
 791 #endif /* CONFIG_ALTIVEC */
 792 #ifdef CONFIG_VSX
 793         if (new->thread.regs && last_task_used_vsx == new)
 794                 new->thread.regs->msr |= MSR_VSX;
 795 #endif /* CONFIG_VSX */
 796 #ifdef CONFIG_SPE
 797         /* Avoid the trap.  On smp this this never happens since
 798          * we don't set last_task_used_spe
 799          */
 800         if (new->thread.regs && last_task_used_spe == new)
 801                 new->thread.regs->msr |= MSR_SPE;
 802 #endif /* CONFIG_SPE */
 803
 804 #endif /* CONFIG_SMP */
 805
 806 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
 807         switch_booke_debug_regs(&new->thread.debug);
 808 #else
 809 /*
 810  * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
 811  * schedule DABR
 812  */
 813 #ifndef CONFIG_HAVE_HW_BREAKPOINT
 814         if (unlikely(!hw_brk_match(&__get_cpu_var(current_brk), &new->thread.hw_brk)))
 815                 set_breakpoint(&new->thread.hw_brk);
 816 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
 817 #endif
 818
 819
 820         new_thread = &new->thread;
 821         old_thread = &current->thread;
 822
 823 #ifdef CONFIG_PPC64
 824         /*
 825          * Collect processor utilization data per process
 826          */
 827         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
 828                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
 829                 long unsigned start_tb, current_tb;
 830                 start_tb = old_thread->start_tb;
 831                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
 832                 old_thread->accum_tb += (current_tb - start_tb);
 833                 new_thread->start_tb = current_tb;
 834         }
 835 #endif /* CONFIG_PPC64 */
 836
 837 #ifdef CONFIG_PPC_BOOK3S_64
 838         batch = &__get_cpu_var(ppc64_tlb_batch);
 839         if (batch->active) {
 840                 current_thread_info()->local_flags |= _TLF_LAZY_MMU;
 841                 if (batch->index)
 842                         __flush_tlb_pending(batch);
 843                 batch->active = 0;
 844         }
 845 #endif /* CONFIG_PPC_BOOK3S_64 */
 846
 847         /*
 848          * We can't take a PMU exception inside _switch() since there is a
 849          * window where the kernel stack SLB and the kernel stack are out
 850          * of sync. Hard disable here.
 851          */
 852         hard_irq_disable();
 853
 854         tm_recheckpoint_new_task(new);
 855
 856         last = _switch(old_thread, new_thread);
 857
 858 #ifdef CONFIG_PPC_BOOK3S_64
 859         if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
 860                 current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
 861                 batch = &__get_cpu_var(ppc64_tlb_batch);
 862                 batch->active = 1;
 863         }
 864 #endif /* CONFIG_PPC_BOOK3S_64 */
 865
 866         return last;
 867 }
 868
 869 static int instructions_to_print = 16;
 870
 871 static void show_instructions(struct pt_regs *regs)
 872 {
 873         int i;
 874         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 875                         sizeof(int));
 876
 877         printk("Instruction dump:");
 878
 879         for (i = 0; i < instructions_to_print; i++) {
 880                 int instr;
 881
 882                 if (!(i % 8))
 883                         printk("\n");
 884
 885 #if !defined(CONFIG_BOOKE)
 886                 /* If executing with the IMMU off, adjust pc rather
 887                  * than print XXXXXXXX.
 888                  */
 889                 if (!(regs->msr & MSR_IR))
 890                         pc = (unsigned long)phys_to_virt(pc);
 891 #endif
 892
 893                 /* We use __get_user here *only* to avoid an OOPS on a
 894                  * bad address because the pc *should* only be a
 895                  * kernel address.
 896                  */
 897                 if (!__kernel_text_address(pc) ||
 898                      __get_user(instr, (unsigned int __user *)pc)) {
 899                         printk(KERN_CONT "XXXXXXXX ");
 900                 } else {
 901                         if (regs->nip == pc)
 902                                 printk(KERN_CONT "<%08x> ", instr);
 903                         else
 904                                 printk(KERN_CONT "%08x ", instr);
 905                 }
 906
 907                 pc += sizeof(int);
 908         }
 909
 910         printk("\n");
 911 }
 912
 913 static struct regbit {
 914         unsigned long bit;
 915         const char *name;
 916 } msr_bits[] = {
 917 #if defined(CONFIG_PPC64) && !defined(CONFIG_BOOKE)
 918         {MSR_SF,        "SF"},
 919         {MSR_HV,        "HV"},
 920 #endif
 921         {MSR_VEC,       "VEC"},
 922         {MSR_VSX,       "VSX"},
 923 #ifdef CONFIG_BOOKE
 924         {MSR_CE,        "CE"},
 925 #endif
 926         {MSR_EE,        "EE"},
 927         {MSR_PR,        "PR"},
 928         {MSR_FP,        "FP"},
 929         {MSR_ME,        "ME"},
 930 #ifdef CONFIG_BOOKE
 931         {MSR_DE,        "DE"},
 932 #else
 933         {MSR_SE,        "SE"},
 934         {MSR_BE,        "BE"},
 935 #endif
 936         {MSR_IR,        "IR"},
 937         {MSR_DR,        "DR"},
 938         {MSR_PMM,       "PMM"},
 939 #ifndef CONFIG_BOOKE
 940         {MSR_RI,        "RI"},
 941         {MSR_LE,        "LE"},
 942 #endif
 943         {0,             NULL}
 944 };
 945
 946 static void printbits(unsigned long val, struct regbit *bits)
 947 {
 948         const char *sep = "";
 949
 950         printk("<");
 951         for (; bits->bit; ++bits)
 952                 if (val & bits->bit) {
 953                         printk("%s%s", sep, bits->name);
 954                         sep = ",";
 955                 }
 956         printk(">");
 957 }
 958
 959 #ifdef CONFIG_PPC64
 960 #define REG             "%016lx"
 961 #define REGS_PER_LINE   4
 962 #define LAST_VOLATILE   13
 963 #else
 964 #define REG             "%08lx"
 965 #define REGS_PER_LINE   8
 966 #define LAST_VOLATILE   12
 967 #endif
 968
 969 void show_regs(struct pt_regs * regs)
 970 {
 971         int i, trap;
 972
 973         show_regs_print_info(KERN_DEFAULT);
 974
 975         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
 976                regs->nip, regs->link, regs->ctr);
 977         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
 978                regs, regs->trap, print_tainted(), init_utsname()->release);
 979         printk("MSR: "REG" ", regs->msr);
 980         printbits(regs->msr, msr_bits);
 981         printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
 982         trap = TRAP(regs);
 983         if ((regs->trap != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
 984                 printk("CFAR: "REG" ", regs->orig_gpr3);
 985         if (trap == 0x200 || trap == 0x300 || trap == 0x600)
 986 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
 987                 printk("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr);
 988 #else
 989                 printk("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
 990 #endif
 991 #ifdef CONFIG_PPC64
 992         printk("SOFTE: %ld ", regs->softe);
 993 #endif
 994 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
 995         if (MSR_TM_ACTIVE(regs->msr))
 996                 printk("\nPACATMSCRATCH: %016llx ", get_paca()->tm_scratch);
 997 #endif
 998
 999         for (i = 0;  i < 32;  i++) {
1000                 if ((i % REGS_PER_LINE) == 0)
1001                         printk("\nGPR%02d: ", i);
1002                 printk(REG " ", regs->gpr[i]);
1003                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
1004                         break;
1005         }
1006         printk("\n");
1007 #ifdef CONFIG_KALLSYMS
1008         /*
1009          * Lookup NIP late so we have the best change of getting the
1010          * above info out without failing
1011          */
1012         printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
1013         printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
1014 #endif
1015         show_stack(current, (unsigned long *) regs->gpr[1]);
1016         if (!user_mode(regs))
1017                 show_instructions(regs);
1018 }
1019
1020 void exit_thread(void)
1021 {
1022         discard_lazy_cpu_state();
1023 }
1024
1025 void flush_thread(void)
1026 {
1027         discard_lazy_cpu_state();
1028
1029 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1030         flush_ptrace_hw_breakpoint(current);
1031 #else /* CONFIG_HAVE_HW_BREAKPOINT */
1032         set_debug_reg_defaults(&current->thread);
1033 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
1034 }
1035
1036 void
1037 release_thread(struct task_struct *t)
1038 {
1039 }
1040
1041 /*
1042  * this gets called so that we can store coprocessor state into memory and
1043  * copy the current task into the new thread.
1044  */
1045 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
1046 {
1047         flush_fp_to_thread(src);
1048         flush_altivec_to_thread(src);
1049         flush_vsx_to_thread(src);
1050         flush_spe_to_thread(src);
1051
1052         *dst = *src;
1053
1054         clear_task_ebb(dst);
1055
1056         return 0;
1057 }
1058
1059 /*
1060  * Copy a thread..
1061  */
1062 extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
1063
1064 int copy_thread(unsigned long clone_flags, unsigned long usp,
1065                 unsigned long arg, struct task_struct *p)
1066 {
1067         struct pt_regs *childregs, *kregs;
1068         extern void ret_from_fork(void);
1069         extern void ret_from_kernel_thread(void);
1070         void (*f)(void);
1071         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
1072
1073         /* Copy registers */
1074         sp -= sizeof(struct pt_regs);
1075         childregs = (struct pt_regs *) sp;
1076         if (unlikely(p->flags & PF_KTHREAD)) {
1077                 struct thread_info *ti = (void *)task_stack_page(p);
1078                 memset(childregs, 0, sizeof(struct pt_regs));
1079                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
1080                 childregs->gpr[14] = usp;       /* function */
1081 #ifdef CONFIG_PPC64
1082                 clear_tsk_thread_flag(p, TIF_32BIT);
1083                 childregs->softe = 1;
1084 #endif
1085                 childregs->gpr[15] = arg;
1086                 p->thread.regs = NULL;  /* no user register state */
1087                 ti->flags |= _TIF_RESTOREALL;
1088                 f = ret_from_kernel_thread;
1089         } else {
1090                 struct pt_regs *regs = current_pt_regs();
1091                 CHECK_FULL_REGS(regs);
1092                 *childregs = *regs;
1093                 if (usp)
1094                         childregs->gpr[1] = usp;
1095                 p->thread.regs = childregs;
1096                 childregs->gpr[3] = 0;  /* Result from fork() */
1097                 if (clone_flags & CLONE_SETTLS) {
1098 #ifdef CONFIG_PPC64
1099                         if (!is_32bit_task())
1100                                 childregs->gpr[13] = childregs->gpr[6];
1101                         else
1102 #endif
1103                                 childregs->gpr[2] = childregs->gpr[6];
1104                 }
1105
1106                 f = ret_from_fork;
1107         }
1108         sp -= STACK_FRAME_OVERHEAD;
1109
1110         /*
1111          * The way this works is that at some point in the future
1112          * some task will call _switch to switch to the new task.
1113          * That will pop off the stack frame created below and start
1114          * the new task running at ret_from_fork.  The new task will
1115          * do some house keeping and then return from the fork or clone
1116          * system call, using the stack frame created above.
1117          */
1118         ((unsigned long *)sp)[0] = 0;
1119         sp -= sizeof(struct pt_regs);
1120         kregs = (struct pt_regs *) sp;
1121         sp -= STACK_FRAME_OVERHEAD;
1122         p->thread.ksp = sp;
1123 #ifdef CONFIG_PPC32
1124         p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
1125                                 _ALIGN_UP(sizeof(struct thread_info), 16);
1126 #endif
1127 #ifdef CONFIG_HAVE_HW_BREAKPOINT
1128         p->thread.ptrace_bps[0] = NULL;
1129 #endif
1130
1131         p->thread.fp_save_area = NULL;
1132 #ifdef CONFIG_ALTIVEC
1133         p->thread.vr_save_area = NULL;
1134 #endif
1135
1136 #ifdef CONFIG_PPC_STD_MMU_64
1137         if (mmu_has_feature(MMU_FTR_SLB)) {
1138                 unsigned long sp_vsid;
1139                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
1140
1141                 if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
1142                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
1143                                 << SLB_VSID_SHIFT_1T;
1144                 else
1145                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
1146                                 << SLB_VSID_SHIFT;
1147                 sp_vsid |= SLB_VSID_KERNEL | llp;
1148                 p->thread.ksp_vsid = sp_vsid;
1149         }
1150 #endif /* CONFIG_PPC_STD_MMU_64 */
1151 #ifdef CONFIG_PPC64
1152         if (cpu_has_feature(CPU_FTR_DSCR)) {
1153                 p->thread.dscr_inherit = current->thread.dscr_inherit;
1154                 p->thread.dscr = current->thread.dscr;
1155         }
1156         if (cpu_has_feature(CPU_FTR_HAS_PPR))
1157                 p->thread.ppr = INIT_PPR;
1158 #endif
1159         /*
1160          * The PPC64 ABI makes use of a TOC to contain function
1161          * pointers.  The function (ret_from_except) is actually a pointer
1162          * to the TOC entry.  The first entry is a pointer to the actual
1163          * function.
1164          */
1165 #ifdef CONFIG_PPC64
1166         kregs->nip = *((unsigned long *)f);
1167 #else
1168         kregs->nip = (unsigned long)f;
1169 #endif
1170         return 0;
1171 }
1172
1173 /*
1174  * Set up a thread for executing a new program
1175  */
1176 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
1177 {
1178 #ifdef CONFIG_PPC64
1179         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
1180 #endif
1181
1182         /*
1183          * If we exec out of a kernel thread then thread.regs will not be
1184          * set.  Do it now.
1185          */
1186         if (!current->thread.regs) {
1187                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
1188                 current->thread.regs = regs - 1;
1189         }
1190
1191         memset(regs->gpr, 0, sizeof(regs->gpr));
1192         regs->ctr = 0;
1193         regs->link = 0;
1194         regs->xer = 0;
1195         regs->ccr = 0;
1196         regs->gpr[1] = sp;
1197
1198         /*
1199          * We have just cleared all the nonvolatile GPRs, so make
1200          * FULL_REGS(regs) return true.  This is necessary to allow
1201          * ptrace to examine the thread immediately after exec.
1202          */
1203         regs->trap &= ~1UL;
1204
1205 #ifdef CONFIG_PPC32
1206         regs->mq = 0;
1207         regs->nip = start;
1208         regs->msr = MSR_USER;
1209 #else
1210         if (!is_32bit_task()) {
1211                 unsigned long entry;
1212
1213                 if (is_elf2_task()) {
1214                         /* Look ma, no function descriptors! */
1215                         entry = start;
1216
1217                         /*
1218                          * Ulrich says:
1219                          *   The latest iteration of the ABI requires that when
1220                          *   calling a function (at its global entry point),
1221                          *   the caller must ensure r12 holds the entry point
1222                          *   address (so that the function can quickly
1223                          *   establish addressability).
1224                          */
1225                         regs->gpr[12] = start;
1226                         /* Make sure that's restored on entry to userspace. */
1227                         set_thread_flag(TIF_RESTOREALL);
1228                 } else {
1229                         unsigned long toc;
1230
1231                         /* start is a relocated pointer to the function
1232                          * descriptor for the elf _start routine.  The first
1233                          * entry in the function descriptor is the entry
1234                          * address of _start and the second entry is the TOC
1235                          * value we need to use.
1236                          */
1237                         __get_user(entry, (unsigned long __user *)start);
1238                         __get_user(toc, (unsigned long __user *)start+1);
1239
1240                         /* Check whether the e_entry function descriptor entries
1241                          * need to be relocated before we can use them.
1242                          */
1243                         if (load_addr != 0) {
1244                                 entry += load_addr;
1245                                 toc   += load_addr;
1246                         }
1247                         regs->gpr[2] = toc;
1248                 }
1249                 regs->nip = entry;
1250                 regs->msr = MSR_USER64;
1251         } else {
1252                 regs->nip = start;
1253                 regs->gpr[2] = 0;
1254                 regs->msr = MSR_USER32;
1255         }
1256 #endif
1257         discard_lazy_cpu_state();
1258 #ifdef CONFIG_VSX
1259         current->thread.used_vsr = 0;
1260 #endif
1261         memset(&current->thread.fp_state, 0, sizeof(current->thread.fp_state));
1262         current->thread.fp_save_area = NULL;
1263 #ifdef CONFIG_ALTIVEC
1264         memset(&current->thread.vr_state, 0, sizeof(current->thread.vr_state));
1265         current->thread.vr_state.vscr.u[3] = 0x00010000; /* Java mode disabled */
1266         current->thread.vr_save_area = NULL;
1267         current->thread.vrsave = 0;
1268         current->thread.used_vr = 0;
1269 #endif /* CONFIG_ALTIVEC */
1270 #ifdef CONFIG_SPE
1271         memset(current->thread.evr, 0, sizeof(current->thread.evr));
1272         current->thread.acc = 0;
1273         current->thread.spefscr = 0;
1274         current->thread.used_spe = 0;
1275 #endif /* CONFIG_SPE */
1276 #ifdef CONFIG_PPC_TRANSACTIONAL_MEM
1277         if (cpu_has_feature(CPU_FTR_TM))
1278                 regs->msr |= MSR_TM;
1279         current->thread.tm_tfhar = 0;
1280         current->thread.tm_texasr = 0;
1281         current->thread.tm_tfiar = 0;
1282 #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
1283 }
1284
1285 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
1286                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
1287
1288 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
1289 {
1290         struct pt_regs *regs = tsk->thread.regs;
1291
1292         /* This is a bit hairy.  If we are an SPE enabled  processor
1293          * (have embedded fp) we store the IEEE exception enable flags in
1294          * fpexc_mode.  fpexc_mode is also used for setting FP exception
1295          * mode (asyn, precise, disabled) for 'Classic' FP. */
1296         if (val & PR_FP_EXC_SW_ENABLE) {
1297 #ifdef CONFIG_SPE
1298                 if (cpu_has_feature(CPU_FTR_SPE)) {
1299                         /*
1300                          * When the sticky exception bits are set
1301                          * directly by userspace, it must call prctl
1302                          * with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE
1303                          * in the existing prctl settings) or
1304                          * PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in
1305                          * the bits being set).  <fenv.h> functions
1306                          * saving and restoring the whole
1307                          * floating-point environment need to do so
1308                          * anyway to restore the prctl settings from
1309                          * the saved environment.
1310                          */
1311                         tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
1312                         tsk->thread.fpexc_mode = val &
1313                                 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
1314                         return 0;
1315                 } else {
1316                         return -EINVAL;
1317                 }
1318 #else
1319                 return -EINVAL;
1320 #endif
1321         }
1322
1323         /* on a CONFIG_SPE this does not hurt us.  The bits that
1324          * __pack_fe01 use do not overlap with bits used for
1325          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
1326          * on CONFIG_SPE implementations are reserved so writing to
1327          * them does not change anything */
1328         if (val > PR_FP_EXC_PRECISE)
1329                 return -EINVAL;
1330         tsk->thread.fpexc_mode = __pack_fe01(val);
1331         if (regs != NULL && (regs->msr & MSR_FP) != 0)
1332                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
1333                         | tsk->thread.fpexc_mode;
1334         return 0;
1335 }
1336
1337 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
1338 {
1339         unsigned int val;
1340
1341         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
1342 #ifdef CONFIG_SPE
1343                 if (cpu_has_feature(CPU_FTR_SPE)) {
1344                         /*
1345                          * When the sticky exception bits are set
1346                          * directly by userspace, it must call prctl
1347                          * with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE
1348                          * in the existing prctl settings) or
1349                          * PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in
1350                          * the bits being set).  <fenv.h> functions
1351                          * saving and restoring the whole
1352                          * floating-point environment need to do so
1353                          * anyway to restore the prctl settings from
1354                          * the saved environment.
1355                          */
1356                         tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
1357                         val = tsk->thread.fpexc_mode;
1358                 } else
1359                         return -EINVAL;
1360 #else
1361                 return -EINVAL;
1362 #endif
1363         else
1364                 val = __unpack_fe01(tsk->thread.fpexc_mode);
1365         return put_user(val, (unsigned int __user *) adr);
1366 }
1367
1368 int set_endian(struct task_struct *tsk, unsigned int val)
1369 {
1370         struct pt_regs *regs = tsk->thread.regs;
1371
1372         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
1373             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
1374                 return -EINVAL;
1375
1376         if (regs == NULL)
1377                 return -EINVAL;
1378
1379         if (val == PR_ENDIAN_BIG)
1380                 regs->msr &= ~MSR_LE;
1381         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
1382                 regs->msr |= MSR_LE;
1383         else
1384                 return -EINVAL;
1385
1386         return 0;
1387 }
1388
1389 int get_endian(struct task_struct *tsk, unsigned long adr)
1390 {
1391         struct pt_regs *regs = tsk->thread.regs;
1392         unsigned int val;
1393
1394         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
1395             !cpu_has_feature(CPU_FTR_REAL_LE))
1396                 return -EINVAL;
1397
1398         if (regs == NULL)
1399                 return -EINVAL;
1400
1401         if (regs->msr & MSR_LE) {
1402                 if (cpu_has_feature(CPU_FTR_REAL_LE))
1403                         val = PR_ENDIAN_LITTLE;
1404                 else
1405                         val = PR_ENDIAN_PPC_LITTLE;
1406         } else
1407                 val = PR_ENDIAN_BIG;
1408
1409         return put_user(val, (unsigned int __user *)adr);
1410 }
1411
1412 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
1413 {
1414         tsk->thread.align_ctl = val;
1415         return 0;
1416 }
1417
1418 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
1419 {
1420         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
1421 }
1422
1423 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
1424                                   unsigned long nbytes)
1425 {
1426         unsigned long stack_page;
1427         unsigned long cpu = task_cpu(p);
1428
1429         /*
1430          * Avoid crashing if the stack has overflowed and corrupted
1431          * task_cpu(p), which is in the thread_info struct.
1432          */
1433         if (cpu < NR_CPUS && cpu_possible(cpu)) {
1434                 stack_page = (unsigned long) hardirq_ctx[cpu];
1435                 if (sp >= stack_page + sizeof(struct thread_struct)
1436                     && sp <= stack_page + THREAD_SIZE - nbytes)
1437                         return 1;
1438
1439                 stack_page = (unsigned long) softirq_ctx[cpu];
1440                 if (sp >= stack_page + sizeof(struct thread_struct)
1441                     && sp <= stack_page + THREAD_SIZE - nbytes)
1442                         return 1;
1443         }
1444         return 0;
1445 }
1446
1447 int validate_sp(unsigned long sp, struct task_struct *p,
1448                        unsigned long nbytes)
1449 {
1450         unsigned long stack_page = (unsigned long)task_stack_page(p);
1451
1452         if (sp >= stack_page + sizeof(struct thread_struct)
1453             && sp <= stack_page + THREAD_SIZE - nbytes)
1454                 return 1;
1455
1456         return valid_irq_stack(sp, p, nbytes);
1457 }
1458
1459 EXPORT_SYMBOL(validate_sp);
1460
1461 unsigned long get_wchan(struct task_struct *p)
1462 {
1463         unsigned long ip, sp;
1464         int count = 0;
1465
1466         if (!p || p == current || p->state == TASK_RUNNING)
1467                 return 0;
1468
1469         sp = p->thread.ksp;
1470         if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1471                 return 0;
1472
1473         do {
1474                 sp = *(unsigned long *)sp;
1475                 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1476                         return 0;
1477                 if (count > 0) {
1478                         ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1479                         if (!in_sched_functions(ip))
1480                                 return ip;
1481                 }
1482         } while (count++ < 16);
1483         return 0;
1484 }
1485
1486 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1487
1488 void show_stack(struct task_struct *tsk, unsigned long *stack)
1489 {
1490         unsigned long sp, ip, lr, newsp;
1491         int count = 0;
1492         int firstframe = 1;
1493 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1494         int curr_frame = current->curr_ret_stack;
1495         extern void return_to_handler(void);
1496         unsigned long rth = (unsigned long)return_to_handler;
1497         unsigned long mrth = -1;
1498 #ifdef CONFIG_PPC64
1499         extern void mod_return_to_handler(void);
1500         rth = *(unsigned long *)rth;
1501         mrth = (unsigned long)mod_return_to_handler;
1502         mrth = *(unsigned long *)mrth;
1503 #endif
1504 #endif
1505
1506         sp = (unsigned long) stack;
1507         if (tsk == NULL)
1508                 tsk = current;
1509         if (sp == 0) {
1510                 if (tsk == current)
1511                         asm("mr %0,1" : "=r" (sp));
1512                 else
1513                         sp = tsk->thread.ksp;
1514         }
1515
1516         lr = 0;
1517         printk("Call Trace:\n");
1518         do {
1519                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1520                         return;
1521
1522                 stack = (unsigned long *) sp;
1523                 newsp = stack[0];
1524                 ip = stack[STACK_FRAME_LR_SAVE];
1525                 if (!firstframe || ip != lr) {
1526                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1527 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1528                         if ((ip == rth || ip == mrth) && curr_frame >= 0) {
1529                                 printk(" (%pS)",
1530                                        (void *)current->ret_stack[curr_frame].ret);
1531                                 curr_frame--;
1532                         }
1533 #endif
1534                         if (firstframe)
1535                                 printk(" (unreliable)");
1536                         printk("\n");
1537                 }
1538                 firstframe = 0;
1539
1540                 /*
1541                  * See if this is an exception frame.
1542                  * We look for the "regshere" marker in the current frame.
1543                  */
1544                 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1545                     && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1546                         struct pt_regs *regs = (struct pt_regs *)
1547                                 (sp + STACK_FRAME_OVERHEAD);
1548                         lr = regs->link;
1549                         printk("--- Exception: %lx at %pS\n    LR = %pS\n",
1550                                regs->trap, (void *)regs->nip, (void *)lr);
1551                         firstframe = 1;
1552                 }
1553
1554                 sp = newsp;
1555         } while (count++ < kstack_depth_to_print);
1556 }
1557
1558 #ifdef CONFIG_PPC64
1559 /* Called with hard IRQs off */
1560 void notrace __ppc64_runlatch_on(void)
1561 {
1562         struct thread_info *ti = current_thread_info();
1563         unsigned long ctrl;
1564
1565         ctrl = mfspr(SPRN_CTRLF);
1566         ctrl |= CTRL_RUNLATCH;
1567         mtspr(SPRN_CTRLT, ctrl);
1568
1569         ti->local_flags |= _TLF_RUNLATCH;
1570 }
1571
1572 /* Called with hard IRQs off */
1573 void notrace __ppc64_runlatch_off(void)
1574 {
1575         struct thread_info *ti = current_thread_info();
1576         unsigned long ctrl;
1577
1578         ti->local_flags &= ~_TLF_RUNLATCH;
1579
1580         ctrl = mfspr(SPRN_CTRLF);
1581         ctrl &= ~CTRL_RUNLATCH;
1582         mtspr(SPRN_CTRLT, ctrl);
1583 }
1584 #endif /* CONFIG_PPC64 */
1585
1586 unsigned long arch_align_stack(unsigned long sp)
1587 {
1588         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
1589                 sp -= get_random_int() & ~PAGE_MASK;
1590         return sp & ~0xf;
1591 }
1592
1593 static inline unsigned long brk_rnd(void)
1594 {
1595         unsigned long rnd = 0;
1596
1597         /* 8MB for 32bit, 1GB for 64bit */
1598         if (is_32bit_task())
1599                 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
1600         else
1601                 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
1602
1603         return rnd << PAGE_SHIFT;
1604 }
1605
1606 unsigned long arch_randomize_brk(struct mm_struct *mm)
1607 {
1608         unsigned long base = mm->brk;
1609         unsigned long ret;
1610
1611 #ifdef CONFIG_PPC_STD_MMU_64
1612         /*
1613          * If we are using 1TB segments and we are allowed to randomise
1614          * the heap, we can put it above 1TB so it is backed by a 1TB
1615          * segment. Otherwise the heap will be in the bottom 1TB
1616          * which always uses 256MB segments and this may result in a
1617          * performance penalty.
1618          */
1619         if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
1620                 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
1621 #endif
1622
1623         ret = PAGE_ALIGN(base + brk_rnd());
1624
1625         if (ret < mm->brk)
1626                 return mm->brk;
1627
1628         return ret;
1629 }
1630
1631 unsigned long randomize_et_dyn(unsigned long base)
1632 {
1633         unsigned long ret = PAGE_ALIGN(base + brk_rnd());
1634
1635         if (ret < base)
1636                 return base;
1637
1638         return ret;
1639 }