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