Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu
[linux-2.6] / 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
41 #include <asm/pgtable.h>
42 #include <asm/uaccess.h>
43 #include <asm/system.h>
44 #include <asm/io.h>
45 #include <asm/processor.h>
46 #include <asm/mmu.h>
47 #include <asm/prom.h>
48 #include <asm/machdep.h>
49 #include <asm/time.h>
50 #include <asm/syscalls.h>
51 #ifdef CONFIG_PPC64
52 #include <asm/firmware.h>
53 #endif
54 #include <linux/kprobes.h>
55 #include <linux/kdebug.h>
56
57 extern unsigned long _get_SP(void);
58
59 #ifndef CONFIG_SMP
60 struct task_struct *last_task_used_math = NULL;
61 struct task_struct *last_task_used_altivec = NULL;
62 struct task_struct *last_task_used_vsx = NULL;
63 struct task_struct *last_task_used_spe = NULL;
64 #endif
65
66 /*
67  * Make sure the floating-point register state in the
68  * the thread_struct is up to date for task tsk.
69  */
70 void flush_fp_to_thread(struct task_struct *tsk)
71 {
72         if (tsk->thread.regs) {
73                 /*
74                  * We need to disable preemption here because if we didn't,
75                  * another process could get scheduled after the regs->msr
76                  * test but before we have finished saving the FP registers
77                  * to the thread_struct.  That process could take over the
78                  * FPU, and then when we get scheduled again we would store
79                  * bogus values for the remaining FP registers.
80                  */
81                 preempt_disable();
82                 if (tsk->thread.regs->msr & MSR_FP) {
83 #ifdef CONFIG_SMP
84                         /*
85                          * This should only ever be called for current or
86                          * for a stopped child process.  Since we save away
87                          * the FP register state on context switch on SMP,
88                          * there is something wrong if a stopped child appears
89                          * to still have its FP state in the CPU registers.
90                          */
91                         BUG_ON(tsk != current);
92 #endif
93                         giveup_fpu(tsk);
94                 }
95                 preempt_enable();
96         }
97 }
98
99 void enable_kernel_fp(void)
100 {
101         WARN_ON(preemptible());
102
103 #ifdef CONFIG_SMP
104         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
105                 giveup_fpu(current);
106         else
107                 giveup_fpu(NULL);       /* just enables FP for kernel */
108 #else
109         giveup_fpu(last_task_used_math);
110 #endif /* CONFIG_SMP */
111 }
112 EXPORT_SYMBOL(enable_kernel_fp);
113
114 #ifdef CONFIG_ALTIVEC
115 void enable_kernel_altivec(void)
116 {
117         WARN_ON(preemptible());
118
119 #ifdef CONFIG_SMP
120         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
121                 giveup_altivec(current);
122         else
123                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
124 #else
125         giveup_altivec(last_task_used_altivec);
126 #endif /* CONFIG_SMP */
127 }
128 EXPORT_SYMBOL(enable_kernel_altivec);
129
130 /*
131  * Make sure the VMX/Altivec register state in the
132  * the thread_struct is up to date for task tsk.
133  */
134 void flush_altivec_to_thread(struct task_struct *tsk)
135 {
136         if (tsk->thread.regs) {
137                 preempt_disable();
138                 if (tsk->thread.regs->msr & MSR_VEC) {
139 #ifdef CONFIG_SMP
140                         BUG_ON(tsk != current);
141 #endif
142                         giveup_altivec(tsk);
143                 }
144                 preempt_enable();
145         }
146 }
147 #endif /* CONFIG_ALTIVEC */
148
149 #ifdef CONFIG_VSX
150 #if 0
151 /* not currently used, but some crazy RAID module might want to later */
152 void enable_kernel_vsx(void)
153 {
154         WARN_ON(preemptible());
155
156 #ifdef CONFIG_SMP
157         if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
158                 giveup_vsx(current);
159         else
160                 giveup_vsx(NULL);       /* just enable vsx for kernel - force */
161 #else
162         giveup_vsx(last_task_used_vsx);
163 #endif /* CONFIG_SMP */
164 }
165 EXPORT_SYMBOL(enable_kernel_vsx);
166 #endif
167
168 void giveup_vsx(struct task_struct *tsk)
169 {
170         giveup_fpu(tsk);
171         giveup_altivec(tsk);
172         __giveup_vsx(tsk);
173 }
174
175 void flush_vsx_to_thread(struct task_struct *tsk)
176 {
177         if (tsk->thread.regs) {
178                 preempt_disable();
179                 if (tsk->thread.regs->msr & MSR_VSX) {
180 #ifdef CONFIG_SMP
181                         BUG_ON(tsk != current);
182 #endif
183                         giveup_vsx(tsk);
184                 }
185                 preempt_enable();
186         }
187 }
188 #endif /* CONFIG_VSX */
189
190 #ifdef CONFIG_SPE
191
192 void enable_kernel_spe(void)
193 {
194         WARN_ON(preemptible());
195
196 #ifdef CONFIG_SMP
197         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
198                 giveup_spe(current);
199         else
200                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
201 #else
202         giveup_spe(last_task_used_spe);
203 #endif /* __SMP __ */
204 }
205 EXPORT_SYMBOL(enable_kernel_spe);
206
207 void flush_spe_to_thread(struct task_struct *tsk)
208 {
209         if (tsk->thread.regs) {
210                 preempt_disable();
211                 if (tsk->thread.regs->msr & MSR_SPE) {
212 #ifdef CONFIG_SMP
213                         BUG_ON(tsk != current);
214 #endif
215                         giveup_spe(tsk);
216                 }
217                 preempt_enable();
218         }
219 }
220 #endif /* CONFIG_SPE */
221
222 #ifndef CONFIG_SMP
223 /*
224  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
225  * and the current task has some state, discard it.
226  */
227 void discard_lazy_cpu_state(void)
228 {
229         preempt_disable();
230         if (last_task_used_math == current)
231                 last_task_used_math = NULL;
232 #ifdef CONFIG_ALTIVEC
233         if (last_task_used_altivec == current)
234                 last_task_used_altivec = NULL;
235 #endif /* CONFIG_ALTIVEC */
236 #ifdef CONFIG_VSX
237         if (last_task_used_vsx == current)
238                 last_task_used_vsx = NULL;
239 #endif /* CONFIG_VSX */
240 #ifdef CONFIG_SPE
241         if (last_task_used_spe == current)
242                 last_task_used_spe = NULL;
243 #endif
244         preempt_enable();
245 }
246 #endif /* CONFIG_SMP */
247
248 void do_dabr(struct pt_regs *regs, unsigned long address,
249                     unsigned long error_code)
250 {
251         siginfo_t info;
252
253         if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
254                         11, SIGSEGV) == NOTIFY_STOP)
255                 return;
256
257         if (debugger_dabr_match(regs))
258                 return;
259
260         /* Clear the DAC and struct entries.  One shot trigger */
261 #if defined(CONFIG_BOOKE)
262         mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) & ~(DBSR_DAC1R | DBSR_DAC1W
263                                                         | DBCR0_IDM));
264 #endif
265
266         /* Clear the DABR */
267         set_dabr(0);
268
269         /* Deliver the signal to userspace */
270         info.si_signo = SIGTRAP;
271         info.si_errno = 0;
272         info.si_code = TRAP_HWBKPT;
273         info.si_addr = (void __user *)address;
274         force_sig_info(SIGTRAP, &info, current);
275 }
276
277 static DEFINE_PER_CPU(unsigned long, current_dabr);
278
279 int set_dabr(unsigned long dabr)
280 {
281         __get_cpu_var(current_dabr) = dabr;
282
283         if (ppc_md.set_dabr)
284                 return ppc_md.set_dabr(dabr);
285
286         /* XXX should we have a CPU_FTR_HAS_DABR ? */
287 #if defined(CONFIG_PPC64) || defined(CONFIG_6xx)
288         mtspr(SPRN_DABR, dabr);
289 #endif
290
291 #if defined(CONFIG_BOOKE)
292         mtspr(SPRN_DAC1, dabr);
293 #endif
294
295         return 0;
296 }
297
298 #ifdef CONFIG_PPC64
299 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
300 #endif
301
302 struct task_struct *__switch_to(struct task_struct *prev,
303         struct task_struct *new)
304 {
305         struct thread_struct *new_thread, *old_thread;
306         unsigned long flags;
307         struct task_struct *last;
308
309 #ifdef CONFIG_SMP
310         /* avoid complexity of lazy save/restore of fpu
311          * by just saving it every time we switch out if
312          * this task used the fpu during the last quantum.
313          *
314          * If it tries to use the fpu again, it'll trap and
315          * reload its fp regs.  So we don't have to do a restore
316          * every switch, just a save.
317          *  -- Cort
318          */
319         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
320                 giveup_fpu(prev);
321 #ifdef CONFIG_ALTIVEC
322         /*
323          * If the previous thread used altivec in the last quantum
324          * (thus changing altivec regs) then save them.
325          * We used to check the VRSAVE register but not all apps
326          * set it, so we don't rely on it now (and in fact we need
327          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
328          *
329          * On SMP we always save/restore altivec regs just to avoid the
330          * complexity of changing processors.
331          *  -- Cort
332          */
333         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
334                 giveup_altivec(prev);
335 #endif /* CONFIG_ALTIVEC */
336 #ifdef CONFIG_VSX
337         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
338                 /* VMX and FPU registers are already save here */
339                 __giveup_vsx(prev);
340 #endif /* CONFIG_VSX */
341 #ifdef CONFIG_SPE
342         /*
343          * If the previous thread used spe in the last quantum
344          * (thus changing spe regs) then save them.
345          *
346          * On SMP we always save/restore spe regs just to avoid the
347          * complexity of changing processors.
348          */
349         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
350                 giveup_spe(prev);
351 #endif /* CONFIG_SPE */
352
353 #else  /* CONFIG_SMP */
354 #ifdef CONFIG_ALTIVEC
355         /* Avoid the trap.  On smp this this never happens since
356          * we don't set last_task_used_altivec -- Cort
357          */
358         if (new->thread.regs && last_task_used_altivec == new)
359                 new->thread.regs->msr |= MSR_VEC;
360 #endif /* CONFIG_ALTIVEC */
361 #ifdef CONFIG_VSX
362         if (new->thread.regs && last_task_used_vsx == new)
363                 new->thread.regs->msr |= MSR_VSX;
364 #endif /* CONFIG_VSX */
365 #ifdef CONFIG_SPE
366         /* Avoid the trap.  On smp this this never happens since
367          * we don't set last_task_used_spe
368          */
369         if (new->thread.regs && last_task_used_spe == new)
370                 new->thread.regs->msr |= MSR_SPE;
371 #endif /* CONFIG_SPE */
372
373 #endif /* CONFIG_SMP */
374
375         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
376                 set_dabr(new->thread.dabr);
377
378 #if defined(CONFIG_BOOKE)
379         /* If new thread DAC (HW breakpoint) is the same then leave it */
380         if (new->thread.dabr)
381                 set_dabr(new->thread.dabr);
382 #endif
383
384         new_thread = &new->thread;
385         old_thread = &current->thread;
386
387 #ifdef CONFIG_PPC64
388         /*
389          * Collect processor utilization data per process
390          */
391         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
392                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
393                 long unsigned start_tb, current_tb;
394                 start_tb = old_thread->start_tb;
395                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
396                 old_thread->accum_tb += (current_tb - start_tb);
397                 new_thread->start_tb = current_tb;
398         }
399 #endif
400
401         local_irq_save(flags);
402
403         account_system_vtime(current);
404         account_process_vtime(current);
405         calculate_steal_time();
406
407         /*
408          * We can't take a PMU exception inside _switch() since there is a
409          * window where the kernel stack SLB and the kernel stack are out
410          * of sync. Hard disable here.
411          */
412         hard_irq_disable();
413         last = _switch(old_thread, new_thread);
414
415         local_irq_restore(flags);
416
417         return last;
418 }
419
420 static int instructions_to_print = 16;
421
422 static void show_instructions(struct pt_regs *regs)
423 {
424         int i;
425         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
426                         sizeof(int));
427
428         printk("Instruction dump:");
429
430         for (i = 0; i < instructions_to_print; i++) {
431                 int instr;
432
433                 if (!(i % 8))
434                         printk("\n");
435
436 #if !defined(CONFIG_BOOKE)
437                 /* If executing with the IMMU off, adjust pc rather
438                  * than print XXXXXXXX.
439                  */
440                 if (!(regs->msr & MSR_IR))
441                         pc = (unsigned long)phys_to_virt(pc);
442 #endif
443
444                 /* We use __get_user here *only* to avoid an OOPS on a
445                  * bad address because the pc *should* only be a
446                  * kernel address.
447                  */
448                 if (!__kernel_text_address(pc) ||
449                      __get_user(instr, (unsigned int __user *)pc)) {
450                         printk("XXXXXXXX ");
451                 } else {
452                         if (regs->nip == pc)
453                                 printk("<%08x> ", instr);
454                         else
455                                 printk("%08x ", instr);
456                 }
457
458                 pc += sizeof(int);
459         }
460
461         printk("\n");
462 }
463
464 static struct regbit {
465         unsigned long bit;
466         const char *name;
467 } msr_bits[] = {
468         {MSR_EE,        "EE"},
469         {MSR_PR,        "PR"},
470         {MSR_FP,        "FP"},
471         {MSR_VEC,       "VEC"},
472         {MSR_VSX,       "VSX"},
473         {MSR_ME,        "ME"},
474         {MSR_CE,        "CE"},
475         {MSR_DE,        "DE"},
476         {MSR_IR,        "IR"},
477         {MSR_DR,        "DR"},
478         {0,             NULL}
479 };
480
481 static void printbits(unsigned long val, struct regbit *bits)
482 {
483         const char *sep = "";
484
485         printk("<");
486         for (; bits->bit; ++bits)
487                 if (val & bits->bit) {
488                         printk("%s%s", sep, bits->name);
489                         sep = ",";
490                 }
491         printk(">");
492 }
493
494 #ifdef CONFIG_PPC64
495 #define REG             "%016lx"
496 #define REGS_PER_LINE   4
497 #define LAST_VOLATILE   13
498 #else
499 #define REG             "%08lx"
500 #define REGS_PER_LINE   8
501 #define LAST_VOLATILE   12
502 #endif
503
504 void show_regs(struct pt_regs * regs)
505 {
506         int i, trap;
507
508         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
509                regs->nip, regs->link, regs->ctr);
510         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
511                regs, regs->trap, print_tainted(), init_utsname()->release);
512         printk("MSR: "REG" ", regs->msr);
513         printbits(regs->msr, msr_bits);
514         printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
515         trap = TRAP(regs);
516         if (trap == 0x300 || trap == 0x600)
517 #if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
518                 printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
519 #else
520                 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
521 #endif
522         printk("TASK = %p[%d] '%s' THREAD: %p",
523                current, task_pid_nr(current), current->comm, task_thread_info(current));
524
525 #ifdef CONFIG_SMP
526         printk(" CPU: %d", raw_smp_processor_id());
527 #endif /* CONFIG_SMP */
528
529         for (i = 0;  i < 32;  i++) {
530                 if ((i % REGS_PER_LINE) == 0)
531                         printk("\n" KERN_INFO "GPR%02d: ", i);
532                 printk(REG " ", regs->gpr[i]);
533                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
534                         break;
535         }
536         printk("\n");
537 #ifdef CONFIG_KALLSYMS
538         /*
539          * Lookup NIP late so we have the best change of getting the
540          * above info out without failing
541          */
542         printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
543         printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
544 #endif
545         show_stack(current, (unsigned long *) regs->gpr[1]);
546         if (!user_mode(regs))
547                 show_instructions(regs);
548 }
549
550 void exit_thread(void)
551 {
552         discard_lazy_cpu_state();
553 }
554
555 void flush_thread(void)
556 {
557 #ifdef CONFIG_PPC64
558         struct thread_info *t = current_thread_info();
559
560         if (test_ti_thread_flag(t, TIF_ABI_PENDING)) {
561                 clear_ti_thread_flag(t, TIF_ABI_PENDING);
562                 if (test_ti_thread_flag(t, TIF_32BIT))
563                         clear_ti_thread_flag(t, TIF_32BIT);
564                 else
565                         set_ti_thread_flag(t, TIF_32BIT);
566         }
567 #endif
568
569         discard_lazy_cpu_state();
570
571         if (current->thread.dabr) {
572                 current->thread.dabr = 0;
573                 set_dabr(0);
574
575 #if defined(CONFIG_BOOKE)
576                 current->thread.dbcr0 &= ~(DBSR_DAC1R | DBSR_DAC1W);
577 #endif
578         }
579 }
580
581 void
582 release_thread(struct task_struct *t)
583 {
584 }
585
586 /*
587  * This gets called before we allocate a new thread and copy
588  * the current task into it.
589  */
590 void prepare_to_copy(struct task_struct *tsk)
591 {
592         flush_fp_to_thread(current);
593         flush_altivec_to_thread(current);
594         flush_vsx_to_thread(current);
595         flush_spe_to_thread(current);
596 }
597
598 /*
599  * Copy a thread..
600  */
601 int copy_thread(unsigned long clone_flags, unsigned long usp,
602                 unsigned long unused, struct task_struct *p,
603                 struct pt_regs *regs)
604 {
605         struct pt_regs *childregs, *kregs;
606         extern void ret_from_fork(void);
607         unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
608
609         CHECK_FULL_REGS(regs);
610         /* Copy registers */
611         sp -= sizeof(struct pt_regs);
612         childregs = (struct pt_regs *) sp;
613         *childregs = *regs;
614         if ((childregs->msr & MSR_PR) == 0) {
615                 /* for kernel thread, set `current' and stackptr in new task */
616                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
617 #ifdef CONFIG_PPC32
618                 childregs->gpr[2] = (unsigned long) p;
619 #else
620                 clear_tsk_thread_flag(p, TIF_32BIT);
621 #endif
622                 p->thread.regs = NULL;  /* no user register state */
623         } else {
624                 childregs->gpr[1] = usp;
625                 p->thread.regs = childregs;
626                 if (clone_flags & CLONE_SETTLS) {
627 #ifdef CONFIG_PPC64
628                         if (!test_thread_flag(TIF_32BIT))
629                                 childregs->gpr[13] = childregs->gpr[6];
630                         else
631 #endif
632                                 childregs->gpr[2] = childregs->gpr[6];
633                 }
634         }
635         childregs->gpr[3] = 0;  /* Result from fork() */
636         sp -= STACK_FRAME_OVERHEAD;
637
638         /*
639          * The way this works is that at some point in the future
640          * some task will call _switch to switch to the new task.
641          * That will pop off the stack frame created below and start
642          * the new task running at ret_from_fork.  The new task will
643          * do some house keeping and then return from the fork or clone
644          * system call, using the stack frame created above.
645          */
646         sp -= sizeof(struct pt_regs);
647         kregs = (struct pt_regs *) sp;
648         sp -= STACK_FRAME_OVERHEAD;
649         p->thread.ksp = sp;
650         p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
651                                 _ALIGN_UP(sizeof(struct thread_info), 16);
652
653 #ifdef CONFIG_PPC64
654         if (cpu_has_feature(CPU_FTR_SLB)) {
655                 unsigned long sp_vsid;
656                 unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
657
658                 if (cpu_has_feature(CPU_FTR_1T_SEGMENT))
659                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
660                                 << SLB_VSID_SHIFT_1T;
661                 else
662                         sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
663                                 << SLB_VSID_SHIFT;
664                 sp_vsid |= SLB_VSID_KERNEL | llp;
665                 p->thread.ksp_vsid = sp_vsid;
666         }
667
668         /*
669          * The PPC64 ABI makes use of a TOC to contain function 
670          * pointers.  The function (ret_from_except) is actually a pointer
671          * to the TOC entry.  The first entry is a pointer to the actual
672          * function.
673          */
674         kregs->nip = *((unsigned long *)ret_from_fork);
675 #else
676         kregs->nip = (unsigned long)ret_from_fork;
677 #endif
678
679         return 0;
680 }
681
682 /*
683  * Set up a thread for executing a new program
684  */
685 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
686 {
687 #ifdef CONFIG_PPC64
688         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
689 #endif
690
691         set_fs(USER_DS);
692
693         /*
694          * If we exec out of a kernel thread then thread.regs will not be
695          * set.  Do it now.
696          */
697         if (!current->thread.regs) {
698                 struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
699                 current->thread.regs = regs - 1;
700         }
701
702         memset(regs->gpr, 0, sizeof(regs->gpr));
703         regs->ctr = 0;
704         regs->link = 0;
705         regs->xer = 0;
706         regs->ccr = 0;
707         regs->gpr[1] = sp;
708
709         /*
710          * We have just cleared all the nonvolatile GPRs, so make
711          * FULL_REGS(regs) return true.  This is necessary to allow
712          * ptrace to examine the thread immediately after exec.
713          */
714         regs->trap &= ~1UL;
715
716 #ifdef CONFIG_PPC32
717         regs->mq = 0;
718         regs->nip = start;
719         regs->msr = MSR_USER;
720 #else
721         if (!test_thread_flag(TIF_32BIT)) {
722                 unsigned long entry, toc;
723
724                 /* start is a relocated pointer to the function descriptor for
725                  * the elf _start routine.  The first entry in the function
726                  * descriptor is the entry address of _start and the second
727                  * entry is the TOC value we need to use.
728                  */
729                 __get_user(entry, (unsigned long __user *)start);
730                 __get_user(toc, (unsigned long __user *)start+1);
731
732                 /* Check whether the e_entry function descriptor entries
733                  * need to be relocated before we can use them.
734                  */
735                 if (load_addr != 0) {
736                         entry += load_addr;
737                         toc   += load_addr;
738                 }
739                 regs->nip = entry;
740                 regs->gpr[2] = toc;
741                 regs->msr = MSR_USER64;
742         } else {
743                 regs->nip = start;
744                 regs->gpr[2] = 0;
745                 regs->msr = MSR_USER32;
746         }
747 #endif
748
749         discard_lazy_cpu_state();
750 #ifdef CONFIG_VSX
751         current->thread.used_vsr = 0;
752 #endif
753         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
754         current->thread.fpscr.val = 0;
755 #ifdef CONFIG_ALTIVEC
756         memset(current->thread.vr, 0, sizeof(current->thread.vr));
757         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
758         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
759         current->thread.vrsave = 0;
760         current->thread.used_vr = 0;
761 #endif /* CONFIG_ALTIVEC */
762 #ifdef CONFIG_SPE
763         memset(current->thread.evr, 0, sizeof(current->thread.evr));
764         current->thread.acc = 0;
765         current->thread.spefscr = 0;
766         current->thread.used_spe = 0;
767 #endif /* CONFIG_SPE */
768 }
769
770 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
771                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
772
773 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
774 {
775         struct pt_regs *regs = tsk->thread.regs;
776
777         /* This is a bit hairy.  If we are an SPE enabled  processor
778          * (have embedded fp) we store the IEEE exception enable flags in
779          * fpexc_mode.  fpexc_mode is also used for setting FP exception
780          * mode (asyn, precise, disabled) for 'Classic' FP. */
781         if (val & PR_FP_EXC_SW_ENABLE) {
782 #ifdef CONFIG_SPE
783                 if (cpu_has_feature(CPU_FTR_SPE)) {
784                         tsk->thread.fpexc_mode = val &
785                                 (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
786                         return 0;
787                 } else {
788                         return -EINVAL;
789                 }
790 #else
791                 return -EINVAL;
792 #endif
793         }
794
795         /* on a CONFIG_SPE this does not hurt us.  The bits that
796          * __pack_fe01 use do not overlap with bits used for
797          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
798          * on CONFIG_SPE implementations are reserved so writing to
799          * them does not change anything */
800         if (val > PR_FP_EXC_PRECISE)
801                 return -EINVAL;
802         tsk->thread.fpexc_mode = __pack_fe01(val);
803         if (regs != NULL && (regs->msr & MSR_FP) != 0)
804                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
805                         | tsk->thread.fpexc_mode;
806         return 0;
807 }
808
809 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
810 {
811         unsigned int val;
812
813         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
814 #ifdef CONFIG_SPE
815                 if (cpu_has_feature(CPU_FTR_SPE))
816                         val = tsk->thread.fpexc_mode;
817                 else
818                         return -EINVAL;
819 #else
820                 return -EINVAL;
821 #endif
822         else
823                 val = __unpack_fe01(tsk->thread.fpexc_mode);
824         return put_user(val, (unsigned int __user *) adr);
825 }
826
827 int set_endian(struct task_struct *tsk, unsigned int val)
828 {
829         struct pt_regs *regs = tsk->thread.regs;
830
831         if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
832             (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
833                 return -EINVAL;
834
835         if (regs == NULL)
836                 return -EINVAL;
837
838         if (val == PR_ENDIAN_BIG)
839                 regs->msr &= ~MSR_LE;
840         else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
841                 regs->msr |= MSR_LE;
842         else
843                 return -EINVAL;
844
845         return 0;
846 }
847
848 int get_endian(struct task_struct *tsk, unsigned long adr)
849 {
850         struct pt_regs *regs = tsk->thread.regs;
851         unsigned int val;
852
853         if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
854             !cpu_has_feature(CPU_FTR_REAL_LE))
855                 return -EINVAL;
856
857         if (regs == NULL)
858                 return -EINVAL;
859
860         if (regs->msr & MSR_LE) {
861                 if (cpu_has_feature(CPU_FTR_REAL_LE))
862                         val = PR_ENDIAN_LITTLE;
863                 else
864                         val = PR_ENDIAN_PPC_LITTLE;
865         } else
866                 val = PR_ENDIAN_BIG;
867
868         return put_user(val, (unsigned int __user *)adr);
869 }
870
871 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
872 {
873         tsk->thread.align_ctl = val;
874         return 0;
875 }
876
877 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
878 {
879         return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
880 }
881
882 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
883
884 int sys_clone(unsigned long clone_flags, unsigned long usp,
885               int __user *parent_tidp, void __user *child_threadptr,
886               int __user *child_tidp, int p6,
887               struct pt_regs *regs)
888 {
889         CHECK_FULL_REGS(regs);
890         if (usp == 0)
891                 usp = regs->gpr[1];     /* stack pointer for child */
892 #ifdef CONFIG_PPC64
893         if (test_thread_flag(TIF_32BIT)) {
894                 parent_tidp = TRUNC_PTR(parent_tidp);
895                 child_tidp = TRUNC_PTR(child_tidp);
896         }
897 #endif
898         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
899 }
900
901 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
902              unsigned long p4, unsigned long p5, unsigned long p6,
903              struct pt_regs *regs)
904 {
905         CHECK_FULL_REGS(regs);
906         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
907 }
908
909 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
910               unsigned long p4, unsigned long p5, unsigned long p6,
911               struct pt_regs *regs)
912 {
913         CHECK_FULL_REGS(regs);
914         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
915                         regs, 0, NULL, NULL);
916 }
917
918 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
919                unsigned long a3, unsigned long a4, unsigned long a5,
920                struct pt_regs *regs)
921 {
922         int error;
923         char *filename;
924
925         filename = getname((char __user *) a0);
926         error = PTR_ERR(filename);
927         if (IS_ERR(filename))
928                 goto out;
929         flush_fp_to_thread(current);
930         flush_altivec_to_thread(current);
931         flush_spe_to_thread(current);
932         error = do_execve(filename, (char __user * __user *) a1,
933                           (char __user * __user *) a2, regs);
934         putname(filename);
935 out:
936         return error;
937 }
938
939 #ifdef CONFIG_IRQSTACKS
940 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
941                                   unsigned long nbytes)
942 {
943         unsigned long stack_page;
944         unsigned long cpu = task_cpu(p);
945
946         /*
947          * Avoid crashing if the stack has overflowed and corrupted
948          * task_cpu(p), which is in the thread_info struct.
949          */
950         if (cpu < NR_CPUS && cpu_possible(cpu)) {
951                 stack_page = (unsigned long) hardirq_ctx[cpu];
952                 if (sp >= stack_page + sizeof(struct thread_struct)
953                     && sp <= stack_page + THREAD_SIZE - nbytes)
954                         return 1;
955
956                 stack_page = (unsigned long) softirq_ctx[cpu];
957                 if (sp >= stack_page + sizeof(struct thread_struct)
958                     && sp <= stack_page + THREAD_SIZE - nbytes)
959                         return 1;
960         }
961         return 0;
962 }
963
964 #else
965 #define valid_irq_stack(sp, p, nb)      0
966 #endif /* CONFIG_IRQSTACKS */
967
968 int validate_sp(unsigned long sp, struct task_struct *p,
969                        unsigned long nbytes)
970 {
971         unsigned long stack_page = (unsigned long)task_stack_page(p);
972
973         if (sp >= stack_page + sizeof(struct thread_struct)
974             && sp <= stack_page + THREAD_SIZE - nbytes)
975                 return 1;
976
977         return valid_irq_stack(sp, p, nbytes);
978 }
979
980 EXPORT_SYMBOL(validate_sp);
981
982 unsigned long get_wchan(struct task_struct *p)
983 {
984         unsigned long ip, sp;
985         int count = 0;
986
987         if (!p || p == current || p->state == TASK_RUNNING)
988                 return 0;
989
990         sp = p->thread.ksp;
991         if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
992                 return 0;
993
994         do {
995                 sp = *(unsigned long *)sp;
996                 if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
997                         return 0;
998                 if (count > 0) {
999                         ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1000                         if (!in_sched_functions(ip))
1001                                 return ip;
1002                 }
1003         } while (count++ < 16);
1004         return 0;
1005 }
1006
1007 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1008
1009 void show_stack(struct task_struct *tsk, unsigned long *stack)
1010 {
1011         unsigned long sp, ip, lr, newsp;
1012         int count = 0;
1013         int firstframe = 1;
1014 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1015         int curr_frame = current->curr_ret_stack;
1016         extern void return_to_handler(void);
1017         unsigned long addr = (unsigned long)return_to_handler;
1018 #ifdef CONFIG_PPC64
1019         addr = *(unsigned long*)addr;
1020 #endif
1021 #endif
1022
1023         sp = (unsigned long) stack;
1024         if (tsk == NULL)
1025                 tsk = current;
1026         if (sp == 0) {
1027                 if (tsk == current)
1028                         asm("mr %0,1" : "=r" (sp));
1029                 else
1030                         sp = tsk->thread.ksp;
1031         }
1032
1033         lr = 0;
1034         printk("Call Trace:\n");
1035         do {
1036                 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1037                         return;
1038
1039                 stack = (unsigned long *) sp;
1040                 newsp = stack[0];
1041                 ip = stack[STACK_FRAME_LR_SAVE];
1042                 if (!firstframe || ip != lr) {
1043                         printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1044 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1045                         if (ip == addr && curr_frame >= 0) {
1046                                 printk(" (%pS)",
1047                                        (void *)current->ret_stack[curr_frame].ret);
1048                                 curr_frame--;
1049                         }
1050 #endif
1051                         if (firstframe)
1052                                 printk(" (unreliable)");
1053                         printk("\n");
1054                 }
1055                 firstframe = 0;
1056
1057                 /*
1058                  * See if this is an exception frame.
1059                  * We look for the "regshere" marker in the current frame.
1060                  */
1061                 if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1062                     && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1063                         struct pt_regs *regs = (struct pt_regs *)
1064                                 (sp + STACK_FRAME_OVERHEAD);
1065                         lr = regs->link;
1066                         printk("--- Exception: %lx at %pS\n    LR = %pS\n",
1067                                regs->trap, (void *)regs->nip, (void *)lr);
1068                         firstframe = 1;
1069                 }
1070
1071                 sp = newsp;
1072         } while (count++ < kstack_depth_to_print);
1073 }
1074
1075 void dump_stack(void)
1076 {
1077         show_stack(current, NULL);
1078 }
1079 EXPORT_SYMBOL(dump_stack);
1080
1081 #ifdef CONFIG_PPC64
1082 void ppc64_runlatch_on(void)
1083 {
1084         unsigned long ctrl;
1085
1086         if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
1087                 HMT_medium();
1088
1089                 ctrl = mfspr(SPRN_CTRLF);
1090                 ctrl |= CTRL_RUNLATCH;
1091                 mtspr(SPRN_CTRLT, ctrl);
1092
1093                 set_thread_flag(TIF_RUNLATCH);
1094         }
1095 }
1096
1097 void ppc64_runlatch_off(void)
1098 {
1099         unsigned long ctrl;
1100
1101         if (cpu_has_feature(CPU_FTR_CTRL) && test_thread_flag(TIF_RUNLATCH)) {
1102                 HMT_medium();
1103
1104                 clear_thread_flag(TIF_RUNLATCH);
1105
1106                 ctrl = mfspr(SPRN_CTRLF);
1107                 ctrl &= ~CTRL_RUNLATCH;
1108                 mtspr(SPRN_CTRLT, ctrl);
1109         }
1110 }
1111 #endif
1112
1113 #if THREAD_SHIFT < PAGE_SHIFT
1114
1115 static struct kmem_cache *thread_info_cache;
1116
1117 struct thread_info *alloc_thread_info(struct task_struct *tsk)
1118 {
1119         struct thread_info *ti;
1120
1121         ti = kmem_cache_alloc(thread_info_cache, GFP_KERNEL);
1122         if (unlikely(ti == NULL))
1123                 return NULL;
1124 #ifdef CONFIG_DEBUG_STACK_USAGE
1125         memset(ti, 0, THREAD_SIZE);
1126 #endif
1127         return ti;
1128 }
1129
1130 void free_thread_info(struct thread_info *ti)
1131 {
1132         kmem_cache_free(thread_info_cache, ti);
1133 }
1134
1135 void thread_info_cache_init(void)
1136 {
1137         thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
1138                                               THREAD_SIZE, 0, NULL);
1139         BUG_ON(thread_info_cache == NULL);
1140 }
1141
1142 #endif /* THREAD_SHIFT < PAGE_SHIFT */
1143
1144 unsigned long arch_align_stack(unsigned long sp)
1145 {
1146         if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
1147                 sp -= get_random_int() & ~PAGE_MASK;
1148         return sp & ~0xf;
1149 }
1150
1151 static inline unsigned long brk_rnd(void)
1152 {
1153         unsigned long rnd = 0;
1154
1155         /* 8MB for 32bit, 1GB for 64bit */
1156         if (is_32bit_task())
1157                 rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
1158         else
1159                 rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
1160
1161         return rnd << PAGE_SHIFT;
1162 }
1163
1164 unsigned long arch_randomize_brk(struct mm_struct *mm)
1165 {
1166         unsigned long ret = PAGE_ALIGN(mm->brk + brk_rnd());
1167
1168         if (ret < mm->brk)
1169                 return mm->brk;
1170
1171         return ret;
1172 }
1173
1174 unsigned long randomize_et_dyn(unsigned long base)
1175 {
1176         unsigned long ret = PAGE_ALIGN(base + brk_rnd());
1177
1178         if (ret < base)
1179                 return base;
1180
1181         return ret;
1182 }