Merge branch 'master'
[linux-2.6] / arch / powerpc / kernel / process.c
1 /*
2  *  arch/ppc/kernel/process.c
3  *
4  *  Derived from "arch/i386/kernel/process.c"
5  *    Copyright (C) 1995  Linus Torvalds
6  *
7  *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
8  *  Paul Mackerras (paulus@cs.anu.edu.au)
9  *
10  *  PowerPC version
11  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
12  *
13  *  This program is free software; you can redistribute it and/or
14  *  modify it under the terms of the GNU General Public License
15  *  as published by the Free Software Foundation; either version
16  *  2 of the License, or (at your option) any later version.
17  */
18
19 #include <linux/config.h>
20 #include <linux/errno.h>
21 #include <linux/sched.h>
22 #include <linux/kernel.h>
23 #include <linux/mm.h>
24 #include <linux/smp.h>
25 #include <linux/smp_lock.h>
26 #include <linux/stddef.h>
27 #include <linux/unistd.h>
28 #include <linux/ptrace.h>
29 #include <linux/slab.h>
30 #include <linux/user.h>
31 #include <linux/elf.h>
32 #include <linux/init.h>
33 #include <linux/prctl.h>
34 #include <linux/init_task.h>
35 #include <linux/module.h>
36 #include <linux/kallsyms.h>
37 #include <linux/mqueue.h>
38 #include <linux/hardirq.h>
39 #include <linux/utsname.h>
40 #include <linux/kprobes.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 #ifdef CONFIG_PPC64
50 #include <asm/firmware.h>
51 #include <asm/time.h>
52 #include <asm/machdep.h>
53 #endif
54
55 extern unsigned long _get_SP(void);
56
57 #ifndef CONFIG_SMP
58 struct task_struct *last_task_used_math = NULL;
59 struct task_struct *last_task_used_altivec = NULL;
60 struct task_struct *last_task_used_spe = NULL;
61 #endif
62
63 /*
64  * Make sure the floating-point register state in the
65  * the thread_struct is up to date for task tsk.
66  */
67 void flush_fp_to_thread(struct task_struct *tsk)
68 {
69         if (tsk->thread.regs) {
70                 /*
71                  * We need to disable preemption here because if we didn't,
72                  * another process could get scheduled after the regs->msr
73                  * test but before we have finished saving the FP registers
74                  * to the thread_struct.  That process could take over the
75                  * FPU, and then when we get scheduled again we would store
76                  * bogus values for the remaining FP registers.
77                  */
78                 preempt_disable();
79                 if (tsk->thread.regs->msr & MSR_FP) {
80 #ifdef CONFIG_SMP
81                         /*
82                          * This should only ever be called for current or
83                          * for a stopped child process.  Since we save away
84                          * the FP register state on context switch on SMP,
85                          * there is something wrong if a stopped child appears
86                          * to still have its FP state in the CPU registers.
87                          */
88                         BUG_ON(tsk != current);
89 #endif
90                         giveup_fpu(current);
91                 }
92                 preempt_enable();
93         }
94 }
95
96 void enable_kernel_fp(void)
97 {
98         WARN_ON(preemptible());
99
100 #ifdef CONFIG_SMP
101         if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
102                 giveup_fpu(current);
103         else
104                 giveup_fpu(NULL);       /* just enables FP for kernel */
105 #else
106         giveup_fpu(last_task_used_math);
107 #endif /* CONFIG_SMP */
108 }
109 EXPORT_SYMBOL(enable_kernel_fp);
110
111 int dump_task_fpu(struct task_struct *tsk, elf_fpregset_t *fpregs)
112 {
113         if (!tsk->thread.regs)
114                 return 0;
115         flush_fp_to_thread(current);
116
117         memcpy(fpregs, &tsk->thread.fpr[0], sizeof(*fpregs));
118
119         return 1;
120 }
121
122 #ifdef CONFIG_ALTIVEC
123 void enable_kernel_altivec(void)
124 {
125         WARN_ON(preemptible());
126
127 #ifdef CONFIG_SMP
128         if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
129                 giveup_altivec(current);
130         else
131                 giveup_altivec(NULL);   /* just enable AltiVec for kernel - force */
132 #else
133         giveup_altivec(last_task_used_altivec);
134 #endif /* CONFIG_SMP */
135 }
136 EXPORT_SYMBOL(enable_kernel_altivec);
137
138 /*
139  * Make sure the VMX/Altivec register state in the
140  * the thread_struct is up to date for task tsk.
141  */
142 void flush_altivec_to_thread(struct task_struct *tsk)
143 {
144         if (tsk->thread.regs) {
145                 preempt_disable();
146                 if (tsk->thread.regs->msr & MSR_VEC) {
147 #ifdef CONFIG_SMP
148                         BUG_ON(tsk != current);
149 #endif
150                         giveup_altivec(current);
151                 }
152                 preempt_enable();
153         }
154 }
155
156 int dump_task_altivec(struct pt_regs *regs, elf_vrregset_t *vrregs)
157 {
158         flush_altivec_to_thread(current);
159         memcpy(vrregs, &current->thread.vr[0], sizeof(*vrregs));
160         return 1;
161 }
162 #endif /* CONFIG_ALTIVEC */
163
164 #ifdef CONFIG_SPE
165
166 void enable_kernel_spe(void)
167 {
168         WARN_ON(preemptible());
169
170 #ifdef CONFIG_SMP
171         if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
172                 giveup_spe(current);
173         else
174                 giveup_spe(NULL);       /* just enable SPE for kernel - force */
175 #else
176         giveup_spe(last_task_used_spe);
177 #endif /* __SMP __ */
178 }
179 EXPORT_SYMBOL(enable_kernel_spe);
180
181 void flush_spe_to_thread(struct task_struct *tsk)
182 {
183         if (tsk->thread.regs) {
184                 preempt_disable();
185                 if (tsk->thread.regs->msr & MSR_SPE) {
186 #ifdef CONFIG_SMP
187                         BUG_ON(tsk != current);
188 #endif
189                         giveup_spe(current);
190                 }
191                 preempt_enable();
192         }
193 }
194
195 int dump_spe(struct pt_regs *regs, elf_vrregset_t *evrregs)
196 {
197         flush_spe_to_thread(current);
198         /* We copy u32 evr[32] + u64 acc + u32 spefscr -> 35 */
199         memcpy(evrregs, &current->thread.evr[0], sizeof(u32) * 35);
200         return 1;
201 }
202 #endif /* CONFIG_SPE */
203
204 int set_dabr(unsigned long dabr)
205 {
206 #ifdef CONFIG_PPC64
207         if (ppc_md.set_dabr)
208                 return ppc_md.set_dabr(dabr);
209 #endif
210
211         mtspr(SPRN_DABR, dabr);
212         return 0;
213 }
214
215 #ifdef CONFIG_PPC64
216 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
217 static DEFINE_PER_CPU(unsigned long, current_dabr);
218 #endif
219
220 struct task_struct *__switch_to(struct task_struct *prev,
221         struct task_struct *new)
222 {
223         struct thread_struct *new_thread, *old_thread;
224         unsigned long flags;
225         struct task_struct *last;
226
227 #ifdef CONFIG_SMP
228         /* avoid complexity of lazy save/restore of fpu
229          * by just saving it every time we switch out if
230          * this task used the fpu during the last quantum.
231          *
232          * If it tries to use the fpu again, it'll trap and
233          * reload its fp regs.  So we don't have to do a restore
234          * every switch, just a save.
235          *  -- Cort
236          */
237         if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
238                 giveup_fpu(prev);
239 #ifdef CONFIG_ALTIVEC
240         /*
241          * If the previous thread used altivec in the last quantum
242          * (thus changing altivec regs) then save them.
243          * We used to check the VRSAVE register but not all apps
244          * set it, so we don't rely on it now (and in fact we need
245          * to save & restore VSCR even if VRSAVE == 0).  -- paulus
246          *
247          * On SMP we always save/restore altivec regs just to avoid the
248          * complexity of changing processors.
249          *  -- Cort
250          */
251         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
252                 giveup_altivec(prev);
253 #endif /* CONFIG_ALTIVEC */
254 #ifdef CONFIG_SPE
255         /*
256          * If the previous thread used spe in the last quantum
257          * (thus changing spe regs) then save them.
258          *
259          * On SMP we always save/restore spe regs just to avoid the
260          * complexity of changing processors.
261          */
262         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
263                 giveup_spe(prev);
264 #endif /* CONFIG_SPE */
265
266 #else  /* CONFIG_SMP */
267 #ifdef CONFIG_ALTIVEC
268         /* Avoid the trap.  On smp this this never happens since
269          * we don't set last_task_used_altivec -- Cort
270          */
271         if (new->thread.regs && last_task_used_altivec == new)
272                 new->thread.regs->msr |= MSR_VEC;
273 #endif /* CONFIG_ALTIVEC */
274 #ifdef CONFIG_SPE
275         /* Avoid the trap.  On smp this this never happens since
276          * we don't set last_task_used_spe
277          */
278         if (new->thread.regs && last_task_used_spe == new)
279                 new->thread.regs->msr |= MSR_SPE;
280 #endif /* CONFIG_SPE */
281
282 #endif /* CONFIG_SMP */
283
284 #ifdef CONFIG_PPC64     /* for now */
285         if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr)) {
286                 set_dabr(new->thread.dabr);
287                 __get_cpu_var(current_dabr) = new->thread.dabr;
288         }
289
290         flush_tlb_pending();
291 #endif
292
293         new_thread = &new->thread;
294         old_thread = &current->thread;
295
296 #ifdef CONFIG_PPC64
297         /*
298          * Collect processor utilization data per process
299          */
300         if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
301                 struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
302                 long unsigned start_tb, current_tb;
303                 start_tb = old_thread->start_tb;
304                 cu->current_tb = current_tb = mfspr(SPRN_PURR);
305                 old_thread->accum_tb += (current_tb - start_tb);
306                 new_thread->start_tb = current_tb;
307         }
308 #endif
309
310         local_irq_save(flags);
311         last = _switch(old_thread, new_thread);
312
313         local_irq_restore(flags);
314
315         return last;
316 }
317
318 static int instructions_to_print = 16;
319
320 #ifdef CONFIG_PPC64
321 #define BAD_PC(pc)      ((REGION_ID(pc) != KERNEL_REGION_ID) && \
322                          (REGION_ID(pc) != VMALLOC_REGION_ID))
323 #else
324 #define BAD_PC(pc)      ((pc) < KERNELBASE)
325 #endif
326
327 static void show_instructions(struct pt_regs *regs)
328 {
329         int i;
330         unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
331                         sizeof(int));
332
333         printk("Instruction dump:");
334
335         for (i = 0; i < instructions_to_print; i++) {
336                 int instr;
337
338                 if (!(i % 8))
339                         printk("\n");
340
341                 if (BAD_PC(pc) || __get_user(instr, (unsigned int *)pc)) {
342                         printk("XXXXXXXX ");
343                 } else {
344                         if (regs->nip == pc)
345                                 printk("<%08x> ", instr);
346                         else
347                                 printk("%08x ", instr);
348                 }
349
350                 pc += sizeof(int);
351         }
352
353         printk("\n");
354 }
355
356 static struct regbit {
357         unsigned long bit;
358         const char *name;
359 } msr_bits[] = {
360         {MSR_EE,        "EE"},
361         {MSR_PR,        "PR"},
362         {MSR_FP,        "FP"},
363         {MSR_ME,        "ME"},
364         {MSR_IR,        "IR"},
365         {MSR_DR,        "DR"},
366         {0,             NULL}
367 };
368
369 static void printbits(unsigned long val, struct regbit *bits)
370 {
371         const char *sep = "";
372
373         printk("<");
374         for (; bits->bit; ++bits)
375                 if (val & bits->bit) {
376                         printk("%s%s", sep, bits->name);
377                         sep = ",";
378                 }
379         printk(">");
380 }
381
382 #ifdef CONFIG_PPC64
383 #define REG             "%016lX"
384 #define REGS_PER_LINE   4
385 #define LAST_VOLATILE   13
386 #else
387 #define REG             "%08lX"
388 #define REGS_PER_LINE   8
389 #define LAST_VOLATILE   12
390 #endif
391
392 void show_regs(struct pt_regs * regs)
393 {
394         int i, trap;
395
396         printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
397                regs->nip, regs->link, regs->ctr);
398         printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
399                regs, regs->trap, print_tainted(), system_utsname.release);
400         printk("MSR: "REG" ", regs->msr);
401         printbits(regs->msr, msr_bits);
402         printk("  CR: %08lX  XER: %08lX\n", regs->ccr, regs->xer);
403         trap = TRAP(regs);
404         if (trap == 0x300 || trap == 0x600)
405                 printk("DAR: "REG", DSISR: "REG"\n", regs->dar, regs->dsisr);
406         printk("TASK = %p[%d] '%s' THREAD: %p",
407                current, current->pid, current->comm, current->thread_info);
408
409 #ifdef CONFIG_SMP
410         printk(" CPU: %d", smp_processor_id());
411 #endif /* CONFIG_SMP */
412
413         for (i = 0;  i < 32;  i++) {
414                 if ((i % REGS_PER_LINE) == 0)
415                         printk("\n" KERN_INFO "GPR%02d: ", i);
416                 printk(REG " ", regs->gpr[i]);
417                 if (i == LAST_VOLATILE && !FULL_REGS(regs))
418                         break;
419         }
420         printk("\n");
421 #ifdef CONFIG_KALLSYMS
422         /*
423          * Lookup NIP late so we have the best change of getting the
424          * above info out without failing
425          */
426         printk("NIP ["REG"] ", regs->nip);
427         print_symbol("%s\n", regs->nip);
428         printk("LR ["REG"] ", regs->link);
429         print_symbol("%s\n", regs->link);
430 #endif
431         show_stack(current, (unsigned long *) regs->gpr[1]);
432         if (!user_mode(regs))
433                 show_instructions(regs);
434 }
435
436 void exit_thread(void)
437 {
438         kprobe_flush_task(current);
439
440 #ifndef CONFIG_SMP
441         if (last_task_used_math == current)
442                 last_task_used_math = NULL;
443 #ifdef CONFIG_ALTIVEC
444         if (last_task_used_altivec == current)
445                 last_task_used_altivec = NULL;
446 #endif /* CONFIG_ALTIVEC */
447 #ifdef CONFIG_SPE
448         if (last_task_used_spe == current)
449                 last_task_used_spe = NULL;
450 #endif
451 #endif /* CONFIG_SMP */
452 }
453
454 void flush_thread(void)
455 {
456 #ifdef CONFIG_PPC64
457         struct thread_info *t = current_thread_info();
458
459         if (t->flags & _TIF_ABI_PENDING)
460                 t->flags ^= (_TIF_ABI_PENDING | _TIF_32BIT);
461 #endif
462         kprobe_flush_task(current);
463
464 #ifndef CONFIG_SMP
465         if (last_task_used_math == current)
466                 last_task_used_math = NULL;
467 #ifdef CONFIG_ALTIVEC
468         if (last_task_used_altivec == current)
469                 last_task_used_altivec = NULL;
470 #endif /* CONFIG_ALTIVEC */
471 #ifdef CONFIG_SPE
472         if (last_task_used_spe == current)
473                 last_task_used_spe = NULL;
474 #endif
475 #endif /* CONFIG_SMP */
476
477 #ifdef CONFIG_PPC64     /* for now */
478         if (current->thread.dabr) {
479                 current->thread.dabr = 0;
480                 set_dabr(0);
481         }
482 #endif
483 }
484
485 void
486 release_thread(struct task_struct *t)
487 {
488 }
489
490 /*
491  * This gets called before we allocate a new thread and copy
492  * the current task into it.
493  */
494 void prepare_to_copy(struct task_struct *tsk)
495 {
496         flush_fp_to_thread(current);
497         flush_altivec_to_thread(current);
498         flush_spe_to_thread(current);
499 }
500
501 /*
502  * Copy a thread..
503  */
504 int copy_thread(int nr, unsigned long clone_flags, unsigned long usp,
505                 unsigned long unused, struct task_struct *p,
506                 struct pt_regs *regs)
507 {
508         struct pt_regs *childregs, *kregs;
509         extern void ret_from_fork(void);
510         unsigned long sp = (unsigned long)p->thread_info + THREAD_SIZE;
511
512         CHECK_FULL_REGS(regs);
513         /* Copy registers */
514         sp -= sizeof(struct pt_regs);
515         childregs = (struct pt_regs *) sp;
516         *childregs = *regs;
517         if ((childregs->msr & MSR_PR) == 0) {
518                 /* for kernel thread, set `current' and stackptr in new task */
519                 childregs->gpr[1] = sp + sizeof(struct pt_regs);
520 #ifdef CONFIG_PPC32
521                 childregs->gpr[2] = (unsigned long) p;
522 #else
523                 clear_ti_thread_flag(p->thread_info, TIF_32BIT);
524 #endif
525                 p->thread.regs = NULL;  /* no user register state */
526         } else {
527                 childregs->gpr[1] = usp;
528                 p->thread.regs = childregs;
529                 if (clone_flags & CLONE_SETTLS) {
530 #ifdef CONFIG_PPC64
531                         if (!test_thread_flag(TIF_32BIT))
532                                 childregs->gpr[13] = childregs->gpr[6];
533                         else
534 #endif
535                                 childregs->gpr[2] = childregs->gpr[6];
536                 }
537         }
538         childregs->gpr[3] = 0;  /* Result from fork() */
539         sp -= STACK_FRAME_OVERHEAD;
540
541         /*
542          * The way this works is that at some point in the future
543          * some task will call _switch to switch to the new task.
544          * That will pop off the stack frame created below and start
545          * the new task running at ret_from_fork.  The new task will
546          * do some house keeping and then return from the fork or clone
547          * system call, using the stack frame created above.
548          */
549         sp -= sizeof(struct pt_regs);
550         kregs = (struct pt_regs *) sp;
551         sp -= STACK_FRAME_OVERHEAD;
552         p->thread.ksp = sp;
553
554 #ifdef CONFIG_PPC64
555         if (cpu_has_feature(CPU_FTR_SLB)) {
556                 unsigned long sp_vsid = get_kernel_vsid(sp);
557
558                 sp_vsid <<= SLB_VSID_SHIFT;
559                 sp_vsid |= SLB_VSID_KERNEL;
560                 if (cpu_has_feature(CPU_FTR_16M_PAGE))
561                         sp_vsid |= SLB_VSID_L;
562
563                 p->thread.ksp_vsid = sp_vsid;
564         }
565
566         /*
567          * The PPC64 ABI makes use of a TOC to contain function 
568          * pointers.  The function (ret_from_except) is actually a pointer
569          * to the TOC entry.  The first entry is a pointer to the actual
570          * function.
571          */
572         kregs->nip = *((unsigned long *)ret_from_fork);
573 #else
574         kregs->nip = (unsigned long)ret_from_fork;
575         p->thread.last_syscall = -1;
576 #endif
577
578         return 0;
579 }
580
581 /*
582  * Set up a thread for executing a new program
583  */
584 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
585 {
586 #ifdef CONFIG_PPC64
587         unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
588 #endif
589
590         set_fs(USER_DS);
591
592         /*
593          * If we exec out of a kernel thread then thread.regs will not be
594          * set.  Do it now.
595          */
596         if (!current->thread.regs) {
597                 unsigned long childregs = (unsigned long)current->thread_info +
598                                                 THREAD_SIZE;
599                 childregs -= sizeof(struct pt_regs);
600                 current->thread.regs = (struct pt_regs *)childregs;
601         }
602
603         memset(regs->gpr, 0, sizeof(regs->gpr));
604         regs->ctr = 0;
605         regs->link = 0;
606         regs->xer = 0;
607         regs->ccr = 0;
608         regs->gpr[1] = sp;
609
610 #ifdef CONFIG_PPC32
611         regs->mq = 0;
612         regs->nip = start;
613         regs->msr = MSR_USER;
614 #else
615         if (!test_thread_flag(TIF_32BIT)) {
616                 unsigned long entry, toc;
617
618                 /* start is a relocated pointer to the function descriptor for
619                  * the elf _start routine.  The first entry in the function
620                  * descriptor is the entry address of _start and the second
621                  * entry is the TOC value we need to use.
622                  */
623                 __get_user(entry, (unsigned long __user *)start);
624                 __get_user(toc, (unsigned long __user *)start+1);
625
626                 /* Check whether the e_entry function descriptor entries
627                  * need to be relocated before we can use them.
628                  */
629                 if (load_addr != 0) {
630                         entry += load_addr;
631                         toc   += load_addr;
632                 }
633                 regs->nip = entry;
634                 regs->gpr[2] = toc;
635                 regs->msr = MSR_USER64;
636         } else {
637                 regs->nip = start;
638                 regs->gpr[2] = 0;
639                 regs->msr = MSR_USER32;
640         }
641 #endif
642
643 #ifndef CONFIG_SMP
644         if (last_task_used_math == current)
645                 last_task_used_math = NULL;
646 #ifdef CONFIG_ALTIVEC
647         if (last_task_used_altivec == current)
648                 last_task_used_altivec = NULL;
649 #endif
650 #ifdef CONFIG_SPE
651         if (last_task_used_spe == current)
652                 last_task_used_spe = NULL;
653 #endif
654 #endif /* CONFIG_SMP */
655         memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
656         current->thread.fpscr.val = 0;
657 #ifdef CONFIG_ALTIVEC
658         memset(current->thread.vr, 0, sizeof(current->thread.vr));
659         memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
660         current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
661         current->thread.vrsave = 0;
662         current->thread.used_vr = 0;
663 #endif /* CONFIG_ALTIVEC */
664 #ifdef CONFIG_SPE
665         memset(current->thread.evr, 0, sizeof(current->thread.evr));
666         current->thread.acc = 0;
667         current->thread.spefscr = 0;
668         current->thread.used_spe = 0;
669 #endif /* CONFIG_SPE */
670 }
671
672 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
673                 | PR_FP_EXC_RES | PR_FP_EXC_INV)
674
675 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
676 {
677         struct pt_regs *regs = tsk->thread.regs;
678
679         /* This is a bit hairy.  If we are an SPE enabled  processor
680          * (have embedded fp) we store the IEEE exception enable flags in
681          * fpexc_mode.  fpexc_mode is also used for setting FP exception
682          * mode (asyn, precise, disabled) for 'Classic' FP. */
683         if (val & PR_FP_EXC_SW_ENABLE) {
684 #ifdef CONFIG_SPE
685                 tsk->thread.fpexc_mode = val &
686                         (PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
687                 return 0;
688 #else
689                 return -EINVAL;
690 #endif
691         }
692
693         /* on a CONFIG_SPE this does not hurt us.  The bits that
694          * __pack_fe01 use do not overlap with bits used for
695          * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
696          * on CONFIG_SPE implementations are reserved so writing to
697          * them does not change anything */
698         if (val > PR_FP_EXC_PRECISE)
699                 return -EINVAL;
700         tsk->thread.fpexc_mode = __pack_fe01(val);
701         if (regs != NULL && (regs->msr & MSR_FP) != 0)
702                 regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
703                         | tsk->thread.fpexc_mode;
704         return 0;
705 }
706
707 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
708 {
709         unsigned int val;
710
711         if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
712 #ifdef CONFIG_SPE
713                 val = tsk->thread.fpexc_mode;
714 #else
715                 return -EINVAL;
716 #endif
717         else
718                 val = __unpack_fe01(tsk->thread.fpexc_mode);
719         return put_user(val, (unsigned int __user *) adr);
720 }
721
722 #define TRUNC_PTR(x)    ((typeof(x))(((unsigned long)(x)) & 0xffffffff))
723
724 int sys_clone(unsigned long clone_flags, unsigned long usp,
725               int __user *parent_tidp, void __user *child_threadptr,
726               int __user *child_tidp, int p6,
727               struct pt_regs *regs)
728 {
729         CHECK_FULL_REGS(regs);
730         if (usp == 0)
731                 usp = regs->gpr[1];     /* stack pointer for child */
732 #ifdef CONFIG_PPC64
733         if (test_thread_flag(TIF_32BIT)) {
734                 parent_tidp = TRUNC_PTR(parent_tidp);
735                 child_tidp = TRUNC_PTR(child_tidp);
736         }
737 #endif
738         return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
739 }
740
741 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
742              unsigned long p4, unsigned long p5, unsigned long p6,
743              struct pt_regs *regs)
744 {
745         CHECK_FULL_REGS(regs);
746         return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
747 }
748
749 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
750               unsigned long p4, unsigned long p5, unsigned long p6,
751               struct pt_regs *regs)
752 {
753         CHECK_FULL_REGS(regs);
754         return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
755                         regs, 0, NULL, NULL);
756 }
757
758 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
759                unsigned long a3, unsigned long a4, unsigned long a5,
760                struct pt_regs *regs)
761 {
762         int error;
763         char *filename;
764
765         filename = getname((char __user *) a0);
766         error = PTR_ERR(filename);
767         if (IS_ERR(filename))
768                 goto out;
769         flush_fp_to_thread(current);
770         flush_altivec_to_thread(current);
771         flush_spe_to_thread(current);
772         error = do_execve(filename, (char __user * __user *) a1,
773                           (char __user * __user *) a2, regs);
774         if (error == 0) {
775                 task_lock(current);
776                 current->ptrace &= ~PT_DTRACE;
777                 task_unlock(current);
778         }
779         putname(filename);
780 out:
781         return error;
782 }
783
784 static int validate_sp(unsigned long sp, struct task_struct *p,
785                        unsigned long nbytes)
786 {
787         unsigned long stack_page = (unsigned long)p->thread_info;
788
789         if (sp >= stack_page + sizeof(struct thread_struct)
790             && sp <= stack_page + THREAD_SIZE - nbytes)
791                 return 1;
792
793 #ifdef CONFIG_IRQSTACKS
794         stack_page = (unsigned long) hardirq_ctx[task_cpu(p)];
795         if (sp >= stack_page + sizeof(struct thread_struct)
796             && sp <= stack_page + THREAD_SIZE - nbytes)
797                 return 1;
798
799         stack_page = (unsigned long) softirq_ctx[task_cpu(p)];
800         if (sp >= stack_page + sizeof(struct thread_struct)
801             && sp <= stack_page + THREAD_SIZE - nbytes)
802                 return 1;
803 #endif
804
805         return 0;
806 }
807
808 #ifdef CONFIG_PPC64
809 #define MIN_STACK_FRAME 112     /* same as STACK_FRAME_OVERHEAD, in fact */
810 #define FRAME_LR_SAVE   2
811 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD + 288)
812 #define REGS_MARKER     0x7265677368657265ul
813 #define FRAME_MARKER    12
814 #else
815 #define MIN_STACK_FRAME 16
816 #define FRAME_LR_SAVE   1
817 #define INT_FRAME_SIZE  (sizeof(struct pt_regs) + STACK_FRAME_OVERHEAD)
818 #define REGS_MARKER     0x72656773ul
819 #define FRAME_MARKER    2
820 #endif
821
822 unsigned long get_wchan(struct task_struct *p)
823 {
824         unsigned long ip, sp;
825         int count = 0;
826
827         if (!p || p == current || p->state == TASK_RUNNING)
828                 return 0;
829
830         sp = p->thread.ksp;
831         if (!validate_sp(sp, p, MIN_STACK_FRAME))
832                 return 0;
833
834         do {
835                 sp = *(unsigned long *)sp;
836                 if (!validate_sp(sp, p, MIN_STACK_FRAME))
837                         return 0;
838                 if (count > 0) {
839                         ip = ((unsigned long *)sp)[FRAME_LR_SAVE];
840                         if (!in_sched_functions(ip))
841                                 return ip;
842                 }
843         } while (count++ < 16);
844         return 0;
845 }
846 EXPORT_SYMBOL(get_wchan);
847
848 static int kstack_depth_to_print = 64;
849
850 void show_stack(struct task_struct *tsk, unsigned long *stack)
851 {
852         unsigned long sp, ip, lr, newsp;
853         int count = 0;
854         int firstframe = 1;
855
856         sp = (unsigned long) stack;
857         if (tsk == NULL)
858                 tsk = current;
859         if (sp == 0) {
860                 if (tsk == current)
861                         asm("mr %0,1" : "=r" (sp));
862                 else
863                         sp = tsk->thread.ksp;
864         }
865
866         lr = 0;
867         printk("Call Trace:\n");
868         do {
869                 if (!validate_sp(sp, tsk, MIN_STACK_FRAME))
870                         return;
871
872                 stack = (unsigned long *) sp;
873                 newsp = stack[0];
874                 ip = stack[FRAME_LR_SAVE];
875                 if (!firstframe || ip != lr) {
876                         printk("["REG"] ["REG"] ", sp, ip);
877                         print_symbol("%s", ip);
878                         if (firstframe)
879                                 printk(" (unreliable)");
880                         printk("\n");
881                 }
882                 firstframe = 0;
883
884                 /*
885                  * See if this is an exception frame.
886                  * We look for the "regshere" marker in the current frame.
887                  */
888                 if (validate_sp(sp, tsk, INT_FRAME_SIZE)
889                     && stack[FRAME_MARKER] == REGS_MARKER) {
890                         struct pt_regs *regs = (struct pt_regs *)
891                                 (sp + STACK_FRAME_OVERHEAD);
892                         printk("--- Exception: %lx", regs->trap);
893                         print_symbol(" at %s\n", regs->nip);
894                         lr = regs->link;
895                         print_symbol("    LR = %s\n", lr);
896                         firstframe = 1;
897                 }
898
899                 sp = newsp;
900         } while (count++ < kstack_depth_to_print);
901 }
902
903 void dump_stack(void)
904 {
905         show_stack(current, NULL);
906 }
907 EXPORT_SYMBOL(dump_stack);