Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc
[linux-2.6.git] / 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 EXPORT_SYMBOL_GPL(flush_fp_to_thread);
100
101 void enable_kernel_fp(void)
102 {
103         WARN_ON(preemptible());
104
105 #ifdef CONFIG_SMP
106         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
107                 giveup_fpu(current);
108         else
109                 giveup_fpu(NULL);       /* just enables FP for kernel */
110 #else
111         giveup_fpu(last_task_used_math);
112 #endif /* CONFIG_SMP */
113 }
114 EXPORT_SYMBOL(enable_kernel_fp);
115
116 #ifdef CONFIG_ALTIVEC
117 void enable_kernel_altivec(void)
118 {
119         WARN_ON(preemptible());
120
121 #ifdef CONFIG_SMP
122         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
123                 giveup_altivec(current);
124         else
125                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
126 #else
127         giveup_altivec(last_task_used_altivec);
128 #endif /* CONFIG_SMP */
129 }
130 EXPORT_SYMBOL(enable_kernel_altivec);
131
132 /*
133  * Make sure the VMX/Altivec register state in the
134  * the thread_struct is up to date for task tsk.
135  */
136 void flush_altivec_to_thread(struct task_struct *tsk)
137 {
138         if (tsk->thread.regs) {
139                 preempt_disable();
140                 if (tsk->thread.regs->msr & MSR_VEC) {
141 #ifdef CONFIG_SMP
142                         BUG_ON(tsk != current);
143 #endif
144                         giveup_altivec(tsk);
145                 }
146                 preempt_enable();
147         }
148 }
149 EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
150 #endif /* CONFIG_ALTIVEC */
151
152 #ifdef CONFIG_VSX
153 #if 0
154 /* not currently used, but some crazy RAID module might want to later */
155 void enable_kernel_vsx(void)
156 {
157         WARN_ON(preemptible());
158
159 #ifdef CONFIG_SMP
160         if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
161                 giveup_vsx(current);
162         else
163                 giveup_vsx(NULL);       /* just enable vsx for kernel - force */
164 #else
165         giveup_vsx(last_task_used_vsx);
166 #endif /* CONFIG_SMP */
167 }
168 EXPORT_SYMBOL(enable_kernel_vsx);
169 #endif
170
171 void giveup_vsx(struct task_struct *tsk)
172 {
173         giveup_fpu(tsk);
174         giveup_altivec(tsk);
175         __giveup_vsx(tsk);
176 }
177
178 void flush_vsx_to_thread(struct task_struct *tsk)
179 {
180         if (tsk->thread.regs) {
181                 preempt_disable();
182                 if (tsk->thread.regs->msr & MSR_VSX) {
183 #ifdef CONFIG_SMP
184                         BUG_ON(tsk != current);
185 #endif
186                         giveup_vsx(tsk);
187                 }
188                 preempt_enable();
189         }
190 }
191 EXPORT_SYMBOL_GPL(flush_vsx_to_thread);
192 #endif /* CONFIG_VSX */
193
194 #ifdef CONFIG_SPE
195
196 void enable_kernel_spe(void)
197 {
198         WARN_ON(preemptible());
199
200 #ifdef CONFIG_SMP
201         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
202                 giveup_spe(current);
203         else
204                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
205 #else
206         giveup_spe(last_task_used_spe);
207 #endif /* __SMP __ */
208 }
209 EXPORT_SYMBOL(enable_kernel_spe);
210
211 void flush_spe_to_thread(struct task_struct *tsk)
212 {
213         if (tsk->thread.regs) {
214                 preempt_disable();
215                 if (tsk->thread.regs->msr & MSR_SPE) {
216 #ifdef CONFIG_SMP
217                         BUG_ON(tsk != current);
218 #endif
219                         tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
220                         giveup_spe(tsk);
221                 }
222                 preempt_enable();
223         }
224 }
225 #endif /* CONFIG_SPE */
226
227 #ifndef CONFIG_SMP
228 /*
229  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
230  * and the current task has some state, discard it.
231  */
232 void discard_lazy_cpu_state(void)
233 {
234         preempt_disable();
235         if (last_task_used_math == current)
236                 last_task_used_math = NULL;
237 #ifdef CONFIG_ALTIVEC
238         if (last_task_used_altivec == current)
239                 last_task_used_altivec = NULL;
240 #endif /* CONFIG_ALTIVEC */
241 #ifdef CONFIG_VSX
242         if (last_task_used_vsx == current)
243                 last_task_used_vsx = NULL;
244 #endif /* CONFIG_VSX */
245 #ifdef CONFIG_SPE
246         if (last_task_used_spe == current)
247                 last_task_used_spe = NULL;
248 #endif
249         preempt_enable();
250 }
251 #endif /* CONFIG_SMP */
252
253 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
254 void do_send_trap(struct pt_regs *regs, unsigned long address,
255                   unsigned long error_code, int signal_code, int breakpt)
256 {
257         siginfo_t info;
258
259         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
260                         11, SIGSEGV) == NOTIFY_STOP)
261                 return;
262
263         /* Deliver the signal to userspace */
264         info.si_signo = SIGTRAP;
265         info.si_errno = breakpt;        /* breakpoint or watchpoint id */
266         info.si_code = signal_code;
267         info.si_addr = (void __user *)address;
268         force_sig_info(SIGTRAP, &info, current);
269 }
270 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
271 void do_dabr(struct pt_regs *regs, unsigned long address,
272                     unsigned long error_code)
273 {
274         siginfo_t info;
275
276         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
277                         11, SIGSEGV) == NOTIFY_STOP)
278                 return;
279
280         if (debugger_dabr_match(regs))
281                 return;
282
283         /* Clear the DABR */
284         set_dabr(0);
285
286         /* Deliver the signal to userspace */
287         info.si_signo = SIGTRAP;
288         info.si_errno = 0;
289         info.si_code = TRAP_HWBKPT;
290         info.si_addr = (void __user *)address;
291         force_sig_info(SIGTRAP, &info, current);
292 }
293 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
294
295 static DEFINE_PER_CPU(unsigned long, current_dabr);
296
297 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
298 /*
299  * Set the debug registers back to their default "safe" values.
300  */
301 static void set_debug_reg_defaults(struct thread_struct *thread)
302 {
303         thread->iac1 = thread->iac2 = 0;
304 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
305         thread->iac3 = thread->iac4 = 0;
306 #endif
307         thread->dac1 = thread->dac2 = 0;
308 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
309         thread->dvc1 = thread->dvc2 = 0;
310 #endif
311         thread->dbcr0 = 0;
312 #ifdef CONFIG_BOOKE
313         /*
314          * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
315          */
316         thread->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |   \
317                         DBCR1_IAC3US | DBCR1_IAC4US;
318         /*
319          * Force Data Address Compare User/Supervisor bits to be User-only
320          * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
321          */
322         thread->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
323 #else
324         thread->dbcr1 = 0;
325 #endif
326 }
327
328 static void prime_debug_regs(struct thread_struct *thread)
329 {
330         mtspr(SPRN_IAC1, thread->iac1);
331         mtspr(SPRN_IAC2, thread->iac2);
332 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
333         mtspr(SPRN_IAC3, thread->iac3);
334         mtspr(SPRN_IAC4, thread->iac4);
335 #endif
336         mtspr(SPRN_DAC1, thread->dac1);
337         mtspr(SPRN_DAC2, thread->dac2);
338 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
339         mtspr(SPRN_DVC1, thread->dvc1);
340         mtspr(SPRN_DVC2, thread->dvc2);
341 #endif
342         mtspr(SPRN_DBCR0, thread->dbcr0);
343         mtspr(SPRN_DBCR1, thread->dbcr1);
344 #ifdef CONFIG_BOOKE
345         mtspr(SPRN_DBCR2, thread->dbcr2);
346 #endif
347 }
348 /*
349  * Unless neither the old or new thread are making use of the
350  * debug registers, set the debug registers from the values
351  * stored in the new thread.
352  */
353 static void switch_booke_debug_regs(struct thread_struct *new_thread)
354 {
355         if ((current->thread.dbcr0 & DBCR0_IDM)
356                 || (new_thread->dbcr0 & DBCR0_IDM))
357                         prime_debug_regs(new_thread);
358 }
359 #else   /* !CONFIG_PPC_ADV_DEBUG_REGS */
360 #ifndef CONFIG_HAVE_HW_BREAKPOINT
361 static void set_debug_reg_defaults(struct thread_struct *thread)
362 {
363         if (thread->dabr) {
364                 thread->dabr = 0;
365                 set_dabr(0);
366         }
367 }
368 #endif /* !CONFIG_HAVE_HW_BREAKPOINT */
369 #endif  /* CONFIG_PPC_ADV_DEBUG_REGS */
370
371 int set_dabr(unsigned long dabr)
372 {
373         __get_cpu_var(current_dabr) = dabr;
374
375         if (ppc_md.set_dabr)
376                 return ppc_md.set_dabr(dabr);
377
378         /* XXX should we have a CPU_FTR_HAS_DABR ? */
379 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
380         mtspr(SPRN_DAC1, dabr);
381 #ifdef CONFIG_PPC_47x
382         isync();
383 #endif
384 #elif defined(CONFIG_PPC_BOOK3S)
385         mtspr(SPRN_DABR, dabr);
386 #endif
387
388
389         return 0;
390 }
391
392 #ifdef CONFIG_PPC64
393 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
394 #endif
395
396 struct task_struct *__switch_to(struct task_struct *prev,
397         struct task_struct *new)
398 {
399         struct thread_struct *new_thread, *old_thread;
400         unsigned long flags;
401         struct task_struct *last;
402 #ifdef CONFIG_PPC_BOOK3S_64
403         struct ppc64_tlb_batch *batch;
404 #endif
405
406 #ifdef CONFIG_SMP
407         /* avoid complexity of lazy save/restore of fpu
408          * by just saving it every time we switch out if
409          * this task used the fpu during the last quantum.
410          *
411          * If it tries to use the fpu again, it'll trap and
412          * reload its fp regs.  So we don't have to do a restore
413          * every switch, just a save.
414          *  -- Cort
415          */
416         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
417                 giveup_fpu(prev);
418 #ifdef CONFIG_ALTIVEC
419         /*
420          * If the previous thread used altivec in the last quantum
421          * (thus changing altivec regs) then save them.
422          * We used to check the VRSAVE register but not all apps
423          * set it, so we don't rely on it now (and in fact we need
424          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
425          *
426          * On SMP we always save/restore altivec regs just to avoid the
427          * complexity of changing processors.
428          *  -- Cort
429          */
430         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
431                 giveup_altivec(prev);
432 #endif /* CONFIG_ALTIVEC */
433 #ifdef CONFIG_VSX
434         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
435                 /* VMX and FPU registers are already save here */
436                 __giveup_vsx(prev);
437 #endif /* CONFIG_VSX */
438 #ifdef CONFIG_SPE
439         /*
440          * If the previous thread used spe in the last quantum
441          * (thus changing spe regs) then save them.
442          *
443          * On SMP we always save/restore spe regs just to avoid the
444          * complexity of changing processors.
445          */
446         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
447                 giveup_spe(prev);
448 #endif /* CONFIG_SPE */
449
450 #else  /* CONFIG_SMP */
451 #ifdef CONFIG_ALTIVEC
452         /* Avoid the trap.  On smp this this never happens since
453          * we don't set last_task_used_altivec -- Cort
454          */
455         if (new->thread.regs && last_task_used_altivec == new)
456                 new->thread.regs->msr |= MSR_VEC;
457 #endif /* CONFIG_ALTIVEC */
458 #ifdef CONFIG_VSX
459         if (new->thread.regs && last_task_used_vsx == new)
460                 new->thread.regs->msr |= MSR_VSX;
461 #endif /* CONFIG_VSX */
462 #ifdef CONFIG_SPE
463         /* Avoid the trap.  On smp this this never happens since
464          * we don't set last_task_used_spe
465          */
466         if (new->thread.regs && last_task_used_spe == new)
467                 new->thread.regs->msr |= MSR_SPE;
468 #endif /* CONFIG_SPE */
469
470 #endif /* CONFIG_SMP */
471
472 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
473         switch_booke_debug_regs(&new->thread);
474 #else
475 /*
476  * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
477  * schedule DABR
478  */
479 #ifndef CONFIG_HAVE_HW_BREAKPOINT
480         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
481                 set_dabr(new->thread.dabr);
482 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
483 #endif
484
485
486         new_thread = &new->thread;
487         old_thread = &current->thread;
488
489 #if defined(CONFIG_PPC_BOOK3E_64)
490         /* XXX Current Book3E code doesn't deal with kernel side DBCR0,
491          * we always hold the user values, so we set it now.
492          *
493          * However, we ensure the kernel MSR:DE is appropriately cleared too
494          * to avoid spurrious single step exceptions in the kernel.
495          *
496          * This will have to change to merge with the ppc32 code at some point,
497          * but I don't like much what ppc32 is doing today so there's some
498          * thinking needed there
499          */
500         if ((new_thread->dbcr0 | old_thread->dbcr0) & DBCR0_IDM) {
501                 u32 dbcr0;
502
503                 mtmsr(mfmsr() & ~MSR_DE);
504                 isync();
505                 dbcr0 = mfspr(SPRN_DBCR0);
506                 dbcr0 = (dbcr0 & DBCR0_EDM) | new_thread->dbcr0;
507                 mtspr(SPRN_DBCR0, dbcr0);
508         }
509 #endif /* CONFIG_PPC64_BOOK3E */
510
511 #ifdef CONFIG_PPC64
512         /*
513          * Collect processor utilization data per process
514          */
515         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
516                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
517                 long unsigned start_tb, current_tb;
518                 start_tb = old_thread->start_tb;
519                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
520                 old_thread->accum_tb += (current_tb - start_tb);
521                 new_thread->start_tb = current_tb;
522         }
523 #endif /* CONFIG_PPC64 */
524
525 #ifdef CONFIG_PPC_BOOK3S_64
526         batch = &__get_cpu_var(ppc64_tlb_batch);
527         if (batch->active) {
528                 current_thread_info()->local_flags |= _TLF_LAZY_MMU;
529                 if (batch->index)
530                         __flush_tlb_pending(batch);
531                 batch->active = 0;
532         }
533 #endif /* CONFIG_PPC_BOOK3S_64 */
534
535         local_irq_save(flags);
536
537         account_system_vtime(current);
538         account_process_vtime(current);
539
540         /*
541          * We can't take a PMU exception inside _switch() since there is a
542          * window where the kernel stack SLB and the kernel stack are out
543          * of sync. Hard disable here.
544          */
545         hard_irq_disable();
546         last = _switch(old_thread, new_thread);
547
548 #ifdef CONFIG_PPC_BOOK3S_64
549         if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
550                 current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
551                 batch = &__get_cpu_var(ppc64_tlb_batch);
552                 batch->active = 1;
553         }
554 #endif /* CONFIG_PPC_BOOK3S_64 */
555
556         local_irq_restore(flags);
557
558         return last;
559 }
560
561 static int instructions_to_print = 16;
562
563 static void show_instructions(struct pt_regs *regs)
564 {
565         int i;
566         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
567                         sizeof(int));
568
569         printk("Instruction dump:");
570
571         for (i = 0; i < instructions_to_print; i++) {
572                 int instr;
573
574                 if (!(i % 8))
575                         printk("\n");
576
577 #if !defined(CONFIG_BOOKE)
578                 /* If executing with the IMMU off, adjust pc rather
579                  * than print XXXXXXXX.
580                  */
581                 if (!(regs->msr & MSR_IR))
582                         pc = (unsigned long)phys_to_virt(pc);
583 #endif
584
585                 /* We use __get_user here *only* to avoid an OOPS on a
586                  * bad address because the pc *should* only be a
587                  * kernel address.
588                  */
589                 if (!__kernel_text_address(pc) ||
590                      __get_user(instr, (unsigned int __user *)pc)) {
591                         printk("XXXXXXXX ");
592                 } else {
593                         if (regs->nip == pc)
594                                 printk("<%08x> ", instr);
595                         else
596                                 printk("%08x ", instr);
597                 }
598
599                 pc += sizeof(int);
600         }
601
602         printk("\n");
603 }
604
605 static struct regbit {
606         unsigned long bit;
607         const char *name;
608 } msr_bits[] = {
609         {MSR_EE,        "EE"},
610         {MSR_PR,        "PR"},
611         {MSR_FP,        "FP"},
612         {MSR_VEC,       "VEC"},
613         {MSR_VSX,       "VSX"},
614         {MSR_ME,        "ME"},
615         {MSR_CE,        "CE"},
616         {MSR_DE,        "DE"},
617         {MSR_IR,        "IR"},
618         {MSR_DR,        "DR"},
619         {0,             NULL}
620 };
621
622 static void printbits(unsigned long val, struct regbit *bits)
623 {
624         const char *sep = "";
625
626         printk("<");
627         for (; bits->bit; ++bits)
628                 if (val & bits->bit) {
629                         printk("%s%s", sep, bits->name);
630                         sep = ",";
631                 }
632         printk(">");
633 }
634
635 #ifdef CONFIG_PPC64
636 #define REG             "%016lx"
637 #define REGS_PER_LINE   4
638 #define LAST_VOLATILE   13
639 #else
640 #define REG             "%08lx"
641 #define REGS_PER_LINE   8
642 #define LAST_VOLATILE   12
643 #endif
644
645 void show_regs(struct pt_regs * regs)
646 {
647         int i, trap;
648
649         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
650                regs->nip, regs->link, regs->ctr);
651         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
652                regs, regs->trap, print_tainted(), init_utsname()->release);
653         printk("MSR: "REG" ", regs->msr);
654         printbits(regs->msr, msr_bits);
655         printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
656         trap = TRAP(regs);
657         if ((regs->trap != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
658                 printk("CFAR: "REG"\n", regs->orig_gpr3);
659         if (trap == 0x300 || trap == 0x600)
660 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
661                 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
662 #else
663                 printk("DAR: "REG", DSISR: %08lx\n", regs->dar, regs->dsisr);
664 #endif
665         printk("TASK = %p[%d] '%s' THREAD: %p",
666                current, task_pid_nr(current), current->comm, task_thread_info(current));
667
668 #ifdef CONFIG_SMP
669         printk(" CPU: %d", raw_smp_processor_id());
670 #endif /* CONFIG_SMP */
671
672         for (i = 0;  i < 32;  i++) {
673                 if ((i % REGS_PER_LINE) == 0)
674                         printk("\nGPR%02d: ", i);
675                 printk(REG " ", regs->gpr[i]);
676                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
677                         break;
678         }
679         printk("\n");
680 #ifdef CONFIG_KALLSYMS
681         /*
682          * Lookup NIP late so we have the best change of getting the
683          * above info out without failing
684          */
685         printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
686         printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
687 #endif
688         show_stack(current, (unsigned long *) regs->gpr[1]);
689         if (!user_mode(regs))
690                 show_instructions(regs);
691 }
692
693 void exit_thread(void)
694 {
695         discard_lazy_cpu_state();
696 }
697
698 void flush_thread(void)
699 {
700         discard_lazy_cpu_state();
701
702 #ifdef CONFIG_HAVE_HW_BREAKPOINT
703         flush_ptrace_hw_breakpoint(current);
704 #else /* CONFIG_HAVE_HW_BREAKPOINT */
705         set_debug_reg_defaults(&current->thread);
706 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
707 }
708
709 void
710 release_thread(struct task_struct *t)
711 {
712 }
713
714 /*
715  * This gets called before we allocate a new thread and copy
716  * the current task into it.
717  */
718 void prepare_to_copy(struct task_struct *tsk)
719 {
720         flush_fp_to_thread(current);
721         flush_altivec_to_thread(current);
722         flush_vsx_to_thread(current);
723         flush_spe_to_thread(current);
724 #ifdef CONFIG_HAVE_HW_BREAKPOINT
725         flush_ptrace_hw_breakpoint(tsk);
726 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
727 }
728
729 /*
730  * Copy a thread..
731  */
732 extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
733
734 int copy_thread(unsigned long clone_flags, unsigned long usp,
735                 unsigned long unused, struct task_struct *p,
736                 struct pt_regs *regs)
737 {
738         struct pt_regs *childregs, *kregs;
739         extern void ret_from_fork(void);
740         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
741
742         CHECK_FULL_REGS(regs);
743         /* Copy registers */
744         sp -= sizeof(struct pt_regs);
745         childregs = (struct pt_regs *) sp;
746         *childregs = *regs;
747         if ((childregs->msr & MSR_PR) == 0) {
748                 /* for kernel thread, set `current' and stackptr in new task */
749                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
750 #ifdef CONFIG_PPC32
751                 childregs->gpr[2] = (unsigned long) p;
752 #else
753                 clear_tsk_thread_flag(p, TIF_32BIT);
754 #endif
755                 p->thread.regs = NULL;  /* no user register state */
756         } else {
757                 childregs->gpr[1] = usp;
758                 p->thread.regs = childregs;
759                 if (clone_flags & CLONE_SETTLS) {
760 #ifdef CONFIG_PPC64
761                         if (!is_32bit_task())
762                                 childregs->gpr[13] = childregs->gpr[6];
763                         else
764 #endif
765                                 childregs->gpr[2] = childregs->gpr[6];
766                 }
767         }
768         childregs->gpr[3] = 0;  /* Result from fork() */
769         sp -= STACK_FRAME_OVERHEAD;
770
771         /*
772          * The way this works is that at some point in the future
773          * some task will call _switch to switch to the new task.
774          * That will pop off the stack frame created below and start
775          * the new task running at ret_from_fork.  The new task will
776          * do some house keeping and then return from the fork or clone
777          * system call, using the stack frame created above.
778          */
779         sp -= sizeof(struct pt_regs);
780         kregs = (struct pt_regs *) sp;
781         sp -= STACK_FRAME_OVERHEAD;
782         p->thread.ksp = sp;
783         p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
784                                 _ALIGN_UP(sizeof(struct thread_info), 16);
785
786 #ifdef CONFIG_PPC_STD_MMU_64
787         if (mmu_has_feature(MMU_FTR_SLB)) {
788                 unsigned long sp_vsid;
789                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
790
791                 if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
792                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
793                                 << SLB_VSID_SHIFT_1T;
794                 else
795                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
796                                 << SLB_VSID_SHIFT;
797                 sp_vsid |= SLB_VSID_KERNEL | llp;
798                 p->thread.ksp_vsid = sp_vsid;
799         }
800 #endif /* CONFIG_PPC_STD_MMU_64 */
801 #ifdef CONFIG_PPC64 
802         if (cpu_has_feature(CPU_FTR_DSCR)) {
803                 if (current->thread.dscr_inherit) {
804                         p->thread.dscr_inherit = 1;
805                         p->thread.dscr = current->thread.dscr;
806                 } else if (0 != dscr_default) {
807                         p->thread.dscr_inherit = 1;
808                         p->thread.dscr = dscr_default;
809                 } else {
810                         p->thread.dscr_inherit = 0;
811                         p->thread.dscr = 0;
812                 }
813         }
814 #endif
815
816         /*
817          * The PPC64 ABI makes use of a TOC to contain function 
818          * pointers.  The function (ret_from_except) is actually a pointer
819          * to the TOC entry.  The first entry is a pointer to the actual
820          * function.
821          */
822 #ifdef CONFIG_PPC64
823         kregs->nip = *((unsigned long *)ret_from_fork);
824 #else
825         kregs->nip = (unsigned long)ret_from_fork;
826 #endif
827
828         return 0;
829 }
830
831 /*
832  * Set up a thread for executing a new program
833  */
834 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
835 {
836 #ifdef CONFIG_PPC64
837         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
838 #endif
839
840         /*
841          * If we exec out of a kernel thread then thread.regs will not be
842          * set.  Do it now.
843          */
844         if (!current->thread.regs) {
845                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
846                 current->thread.regs = regs - 1;
847         }
848
849         memset(regs->gpr, 0, sizeof(regs->gpr));
850         regs->ctr = 0;
851         regs->link = 0;
852         regs->xer = 0;
853         regs->ccr = 0;
854         regs->gpr[1] = sp;
855
856         /*
857          * We have just cleared all the nonvolatile GPRs, so make
858          * FULL_REGS(regs) return true.  This is necessary to allow
859          * ptrace to examine the thread immediately after exec.
860          */
861         regs->trap &= ~1UL;
862
863 #ifdef CONFIG_PPC32
864         regs->mq = 0;
865         regs->nip = start;
866         regs->msr = MSR_USER;
867 #else
868         if (!is_32bit_task()) {
869                 unsigned long entry, toc;
870
871                 /* start is a relocated pointer to the function descriptor for
872                  * the elf _start routine.  The first entry in the function
873                  * descriptor is the entry address of _start and the second
874                  * entry is the TOC value we need to use.
875                  */
876                 __get_user(entry, (unsigned long __user *)start);
877                 __get_user(toc, (unsigned long __user *)start+1);
878
879                 /* Check whether the e_entry function descriptor entries
880                  * need to be relocated before we can use them.
881                  */
882                 if (load_addr != 0) {
883                         entry += load_addr;
884                         toc   += load_addr;
885                 }
886                 regs->nip = entry;
887                 regs->gpr[2] = toc;
888                 regs->msr = MSR_USER64;
889         } else {
890                 regs->nip = start;
891                 regs->gpr[2] = 0;
892                 regs->msr = MSR_USER32;
893         }
894 #endif
895
896         discard_lazy_cpu_state();
897 #ifdef CONFIG_VSX
898         current->thread.used_vsr = 0;
899 #endif
900         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
901         current->thread.fpscr.val = 0;
902 #ifdef CONFIG_ALTIVEC
903         memset(current->thread.vr, 0, sizeof(current->thread.vr));
904         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
905         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
906         current->thread.vrsave = 0;
907         current->thread.used_vr = 0;
908 #endif /* CONFIG_ALTIVEC */
909 #ifdef CONFIG_SPE
910         memset(current->thread.evr, 0, sizeof(current->thread.evr));
911         current->thread.acc = 0;
912         current->thread.spefscr = 0;
913         current->thread.used_spe = 0;
914 #endif /* CONFIG_SPE */
915 }
916
917 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
918                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
919
920 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
921 {
922         struct pt_regs *regs = tsk->thread.regs;
923
924         /* This is a bit hairy.  If we are an SPE enabled  processor
925          * (have embedded fp) we store the IEEE exception enable flags in
926          * fpexc_mode.  fpexc_mode is also used for setting FP exception
927          * mode (asyn, precise, disabled) for 'Classic' FP. */
928         if (val & PR_FP_EXC_SW_ENABLE) {
929 #ifdef CONFIG_SPE
930                 if (cpu_has_feature(CPU_FTR_SPE)) {
931                         tsk->thread.fpexc_mode = val &
932                                 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
933                         return 0;
934                 } else {
935                         return -EINVAL;
936                 }
937 #else
938                 return -EINVAL;
939 #endif
940         }
941
942         /* on a CONFIG_SPE this does not hurt us.  The bits that
943          * __pack_fe01 use do not overlap with bits used for
944          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
945          * on CONFIG_SPE implementations are reserved so writing to
946          * them does not change anything */
947         if (val > PR_FP_EXC_PRECISE)
948                 return -EINVAL;
949         tsk->thread.fpexc_mode = __pack_fe01(val);
950         if (regs != NULL && (regs->msr & MSR_FP) != 0)
951                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
952                         | tsk->thread.fpexc_mode;
953         return 0;
954 }
955
956 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
957 {
958         unsigned int val;
959
960         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
961 #ifdef CONFIG_SPE
962                 if (cpu_has_feature(CPU_FTR_SPE))
963                         val = tsk->thread.fpexc_mode;
964                 else
965                         return -EINVAL;
966 #else
967                 return -EINVAL;
968 #endif
969         else
970                 val = __unpack_fe01(tsk->thread.fpexc_mode);
971         return put_user(val, (unsigned int __user *) adr);
972 }
973
974 int set_endian(struct task_struct *tsk, unsigned int val)
975 {
976         struct pt_regs *regs = tsk->thread.regs;
977
978         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
979             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
980                 return -EINVAL;
981
982         if (regs == NULL)
983                 return -EINVAL;
984
985         if (val == PR_ENDIAN_BIG)
986                 regs->msr &= ~MSR_LE;
987         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
988                 regs->msr |= MSR_LE;
989         else
990                 return -EINVAL;
991
992         return 0;
993 }
994
995 int get_endian(struct task_struct *tsk, unsigned long adr)
996 {
997         struct pt_regs *regs = tsk->thread.regs;
998         unsigned int val;
999
1000         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
1001             !cpu_has_feature(CPU_FTR_REAL_LE))
1002                 return -EINVAL;
1003
1004         if (regs == NULL)
1005                 return -EINVAL;
1006
1007         if (regs->msr & MSR_LE) {
1008                 if (cpu_has_feature(CPU_FTR_REAL_LE))
1009                         val = PR_ENDIAN_LITTLE;
1010                 else
1011                         val = PR_ENDIAN_PPC_LITTLE;
1012         } else
1013                 val = PR_ENDIAN_BIG;
1014
1015         return put_user(val, (unsigned int __user *)adr);
1016 }
1017
1018 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
1019 {
1020         tsk->thread.align_ctl = val;
1021         return 0;
1022 }
1023
1024 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
1025 {
1026         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
1027 }
1028
1029 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
1030
1031 int sys_clone(unsigned long clone_flags, unsigned long usp,
1032               int __user *parent_tidp, void __user *child_threadptr,
1033               int __user *child_tidp, int p6,
1034               struct pt_regs *regs)
1035 {
1036         CHECK_FULL_REGS(regs);
1037         if (usp == 0)
1038                 usp = regs->gpr[1];     /* stack pointer for child */
1039 #ifdef CONFIG_PPC64
1040         if (is_32bit_task()) {
1041                 parent_tidp = TRUNC_PTR(parent_tidp);
1042                 child_tidp = TRUNC_PTR(child_tidp);
1043         }
1044 #endif
1045         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
1046 }
1047
1048 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
1049              unsigned long p4, unsigned long p5, unsigned long p6,
1050              struct pt_regs *regs)
1051 {
1052         CHECK_FULL_REGS(regs);
1053         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
1054 }
1055
1056 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
1057               unsigned long p4, unsigned long p5, unsigned long p6,
1058               struct pt_regs *regs)
1059 {
1060         CHECK_FULL_REGS(regs);
1061         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
1062                         regs, 0, NULL, NULL);
1063 }
1064
1065 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
1066                unsigned long a3, unsigned long a4, unsigned long a5,
1067                struct pt_regs *regs)
1068 {
1069         int error;
1070         char *filename;
1071
1072         filename = getname((const char __user *) a0);
1073         error = PTR_ERR(filename);
1074         if (IS_ERR(filename))
1075                 goto out;
1076         flush_fp_to_thread(current);
1077         flush_altivec_to_thread(current);
1078         flush_spe_to_thread(current);
1079         error = do_execve(filename,
1080                           (const char __user *const __user *) a1,
1081                           (const char __user *const __user *) a2, regs);
1082         putname(filename);
1083 out:
1084         return error;
1085 }
1086
1087 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
1088                                   unsigned long nbytes)
1089 {
1090         unsigned long stack_page;
1091         unsigned long cpu = task_cpu(p);
1092
1093         /*
1094          * Avoid crashing if the stack has overflowed and corrupted
1095          * task_cpu(p), which is in the thread_info struct.
1096          */
1097         if (cpu < NR_CPUS && cpu_possible(cpu)) {
1098                 stack_page = (unsigned long) hardirq_ctx[cpu];
1099                 if (sp >= stack_page + sizeof(struct thread_struct)
1100                     && sp <= stack_page + THREAD_SIZE - nbytes)
1101                         return 1;
1102
1103                 stack_page = (unsigned long) softirq_ctx[cpu];
1104                 if (sp >= stack_page + sizeof(struct thread_struct)
1105                     && sp <= stack_page + THREAD_SIZE - nbytes)
1106                         return 1;
1107         }
1108         return 0;
1109 }
1110
1111 int validate_sp(unsigned long sp, struct task_struct *p,
1112                        unsigned long nbytes)
1113 {
1114         unsigned long stack_page = (unsigned long)task_stack_page(p);
1115
1116         if (sp >= stack_page + sizeof(struct thread_struct)
1117             && sp <= stack_page + THREAD_SIZE - nbytes)
1118                 return 1;
1119
1120         return valid_irq_stack(sp, p, nbytes);
1121 }
1122
1123 EXPORT_SYMBOL(validate_sp);
1124
1125 unsigned long get_wchan(struct task_struct *p)
1126 {
1127         unsigned long ip, sp;
1128         int count = 0;
1129
1130         if (!p || p == current || p->state == TASK_RUNNING)
1131                 return 0;
1132
1133         sp = p->thread.ksp;
1134         if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1135                 return 0;
1136
1137         do {
1138                 sp = *(unsigned long *)sp;
1139                 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1140                         return 0;
1141                 if (count > 0) {
1142                         ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1143                         if (!in_sched_functions(ip))
1144                                 return ip;
1145                 }
1146         } while (count++ < 16);
1147         return 0;
1148 }
1149
1150 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1151
1152 void show_stack(struct task_struct *tsk, unsigned long *stack)
1153 {
1154         unsigned long sp, ip, lr, newsp;
1155         int count = 0;
1156         int firstframe = 1;
1157 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1158         int curr_frame = current->curr_ret_stack;
1159         extern void return_to_handler(void);
1160         unsigned long rth = (unsigned long)return_to_handler;
1161         unsigned long mrth = -1;
1162 #ifdef CONFIG_PPC64
1163         extern void mod_return_to_handler(void);
1164         rth = *(unsigned long *)rth;
1165         mrth = (unsigned long)mod_return_to_handler;
1166         mrth = *(unsigned long *)mrth;
1167 #endif
1168 #endif
1169
1170         sp = (unsigned long) stack;
1171         if (tsk == NULL)
1172                 tsk = current;
1173         if (sp == 0) {
1174                 if (tsk == current)
1175                         asm("mr %0,1" : "=r" (sp));
1176                 else
1177                         sp = tsk->thread.ksp;
1178         }
1179
1180         lr = 0;
1181         printk("Call Trace:\n");
1182         do {
1183                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1184                         return;
1185
1186                 stack = (unsigned long *) sp;
1187                 newsp = stack[0];
1188                 ip = stack[STACK_FRAME_LR_SAVE];
1189                 if (!firstframe || ip != lr) {
1190                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1191 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1192                         if ((ip == rth || ip == mrth) && curr_frame >= 0) {
1193                                 printk(" (%pS)",
1194                                        (void *)current->ret_stack[curr_frame].ret);
1195                                 curr_frame--;
1196                         }
1197 #endif
1198                         if (firstframe)
1199                                 printk(" (unreliable)");
1200                         printk("\n");
1201                 }
1202                 firstframe = 0;
1203
1204                 /*
1205                  * See if this is an exception frame.
1206                  * We look for the "regshere" marker in the current frame.
1207                  */
1208                 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1209                     && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1210                         struct pt_regs *regs = (struct pt_regs *)
1211                                 (sp + STACK_FRAME_OVERHEAD);
1212                         lr = regs->link;
1213                         printk("--- Exception: %lx at %pS\n    LR = %pS\n",
1214                                regs->trap, (void *)regs->nip, (void *)lr);
1215                         firstframe = 1;
1216                 }
1217
1218                 sp = newsp;
1219         } while (count++ < kstack_depth_to_print);
1220 }
1221
1222 void dump_stack(void)
1223 {
1224         show_stack(current, NULL);
1225 }
1226 EXPORT_SYMBOL(dump_stack);
1227
1228 #ifdef CONFIG_PPC64
1229 void ppc64_runlatch_on(void)
1230 {
1231         unsigned long ctrl;
1232
1233         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
1234                 HMT_medium();
1235
1236                 ctrl = mfspr(SPRN_CTRLF);
1237                 ctrl |= CTRL_RUNLATCH;
1238                 mtspr(SPRN_CTRLT, ctrl);
1239
1240                 set_thread_flag(TIF_RUNLATCH);
1241         }
1242 }
1243
1244 void __ppc64_runlatch_off(void)
1245 {
1246         unsigned long ctrl;
1247
1248         HMT_medium();
1249
1250         clear_thread_flag(TIF_RUNLATCH);
1251
1252         ctrl = mfspr(SPRN_CTRLF);
1253         ctrl &= ~CTRL_RUNLATCH;
1254         mtspr(SPRN_CTRLT, ctrl);
1255 }
1256 #endif
1257
1258 #if THREAD_SHIFT < PAGE_SHIFT
1259
1260 static struct kmem_cache *thread_info_cache;
1261
1262 struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
1263 {
1264         struct thread_info *ti;
1265
1266         ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
1267         if (unlikely(ti == NULL))
1268                 return NULL;
1269 #ifdef CONFIG_DEBUG_STACK_USAGE
1270         memset(ti, 0, THREAD_SIZE);
1271 #endif
1272         return ti;
1273 }
1274
1275 void free_thread_info(struct thread_info *ti)
1276 {
1277         kmem_cache_free(thread_info_cache, ti);
1278 }
1279
1280 void thread_info_cache_init(void)
1281 {
1282         thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
1283                                               THREAD_SIZE, 0, NULL);
1284         BUG_ON(thread_info_cache == NULL);
1285 }
1286
1287 #endif /* THREAD_SHIFT < PAGE_SHIFT */
1288
1289 unsigned long arch_align_stack(unsigned long sp)
1290 {
1291         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
1292                 sp -= get_random_int() & ~PAGE_MASK;
1293         return sp & ~0xf;
1294 }
1295
1296 static inline unsigned long brk_rnd(void)
1297 {
1298         unsigned long rnd = 0;
1299
1300         /* 8MB for 32bit, 1GB for 64bit */
1301         if (is_32bit_task())
1302                 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
1303         else
1304                 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
1305
1306         return rnd << PAGE_SHIFT;
1307 }
1308
1309 unsigned long arch_randomize_brk(struct mm_struct *mm)
1310 {
1311         unsigned long base = mm->brk;
1312         unsigned long ret;
1313
1314 #ifdef CONFIG_PPC_STD_MMU_64
1315         /*
1316          * If we are using 1TB segments and we are allowed to randomise
1317          * the heap, we can put it above 1TB so it is backed by a 1TB
1318          * segment. Otherwise the heap will be in the bottom 1TB
1319          * which always uses 256MB segments and this may result in a
1320          * performance penalty.
1321          */
1322         if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
1323                 base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
1324 #endif
1325
1326         ret = PAGE_ALIGN(base + brk_rnd());
1327
1328         if (ret < mm->brk)
1329                 return mm->brk;
1330
1331         return ret;
1332 }
1333
1334 unsigned long randomize_et_dyn(unsigned long base)
1335 {
1336         unsigned long ret = PAGE_ALIGN(base + brk_rnd());
1337
1338         if (ret < base)
1339                 return base;
1340
1341         return ret;
1342 }