xref: /openbmc/linux/arch/powerpc/kernel/process.c (revision 7fe2f639)
1 /*
2  *  Derived from "arch/i386/kernel/process.c"
3  *    Copyright (C) 1995  Linus Torvalds
4  *
5  *  Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
6  *  Paul Mackerras (paulus@cs.anu.edu.au)
7  *
8  *  PowerPC version
9  *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
10  *
11  *  This program is free software; you can redistribute it and/or
12  *  modify it under the terms of the GNU General Public License
13  *  as published by the Free Software Foundation; either version
14  *  2 of the License, or (at your option) any later version.
15  */
16 
17 #include <linux/errno.h>
18 #include <linux/sched.h>
19 #include <linux/kernel.h>
20 #include <linux/mm.h>
21 #include <linux/smp.h>
22 #include <linux/stddef.h>
23 #include <linux/unistd.h>
24 #include <linux/ptrace.h>
25 #include <linux/slab.h>
26 #include <linux/user.h>
27 #include <linux/elf.h>
28 #include <linux/init.h>
29 #include <linux/prctl.h>
30 #include <linux/init_task.h>
31 #include <linux/module.h>
32 #include <linux/kallsyms.h>
33 #include <linux/mqueue.h>
34 #include <linux/hardirq.h>
35 #include <linux/utsname.h>
36 #include <linux/ftrace.h>
37 #include <linux/kernel_stat.h>
38 #include <linux/personality.h>
39 #include <linux/random.h>
40 #include <linux/hw_breakpoint.h>
41 
42 #include <asm/pgtable.h>
43 #include <asm/uaccess.h>
44 #include <asm/system.h>
45 #include <asm/io.h>
46 #include <asm/processor.h>
47 #include <asm/mmu.h>
48 #include <asm/prom.h>
49 #include <asm/machdep.h>
50 #include <asm/time.h>
51 #include <asm/syscalls.h>
52 #ifdef CONFIG_PPC64
53 #include <asm/firmware.h>
54 #endif
55 #include <linux/kprobes.h>
56 #include <linux/kdebug.h>
57 
58 extern unsigned long _get_SP(void);
59 
60 #ifndef CONFIG_SMP
61 struct task_struct *last_task_used_math = NULL;
62 struct task_struct *last_task_used_altivec = NULL;
63 struct task_struct *last_task_used_vsx = NULL;
64 struct task_struct *last_task_used_spe = NULL;
65 #endif
66 
67 /*
68  * Make sure the floating-point register state in the
69  * the thread_struct is up to date for task tsk.
70  */
71 void flush_fp_to_thread(struct task_struct *tsk)
72 {
73 	if (tsk->thread.regs) {
74 		/*
75 		 * We need to disable preemption here because if we didn't,
76 		 * another process could get scheduled after the regs->msr
77 		 * test but before we have finished saving the FP registers
78 		 * to the thread_struct.  That process could take over the
79 		 * FPU, and then when we get scheduled again we would store
80 		 * bogus values for the remaining FP registers.
81 		 */
82 		preempt_disable();
83 		if (tsk->thread.regs->msr & MSR_FP) {
84 #ifdef CONFIG_SMP
85 			/*
86 			 * This should only ever be called for current or
87 			 * for a stopped child process.  Since we save away
88 			 * the FP register state on context switch on SMP,
89 			 * there is something wrong if a stopped child appears
90 			 * to still have its FP state in the CPU registers.
91 			 */
92 			BUG_ON(tsk != current);
93 #endif
94 			giveup_fpu(tsk);
95 		}
96 		preempt_enable();
97 	}
98 }
99 
100 void enable_kernel_fp(void)
101 {
102 	WARN_ON(preemptible());
103 
104 #ifdef CONFIG_SMP
105 	if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
106 		giveup_fpu(current);
107 	else
108 		giveup_fpu(NULL);	/* just enables FP for kernel */
109 #else
110 	giveup_fpu(last_task_used_math);
111 #endif /* CONFIG_SMP */
112 }
113 EXPORT_SYMBOL(enable_kernel_fp);
114 
115 #ifdef CONFIG_ALTIVEC
116 void enable_kernel_altivec(void)
117 {
118 	WARN_ON(preemptible());
119 
120 #ifdef CONFIG_SMP
121 	if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
122 		giveup_altivec(current);
123 	else
124 		giveup_altivec(NULL);	/* just enable AltiVec for kernel - force */
125 #else
126 	giveup_altivec(last_task_used_altivec);
127 #endif /* CONFIG_SMP */
128 }
129 EXPORT_SYMBOL(enable_kernel_altivec);
130 
131 /*
132  * Make sure the VMX/Altivec register state in the
133  * the thread_struct is up to date for task tsk.
134  */
135 void flush_altivec_to_thread(struct task_struct *tsk)
136 {
137 	if (tsk->thread.regs) {
138 		preempt_disable();
139 		if (tsk->thread.regs->msr & MSR_VEC) {
140 #ifdef CONFIG_SMP
141 			BUG_ON(tsk != current);
142 #endif
143 			giveup_altivec(tsk);
144 		}
145 		preempt_enable();
146 	}
147 }
148 #endif /* CONFIG_ALTIVEC */
149 
150 #ifdef CONFIG_VSX
151 #if 0
152 /* not currently used, but some crazy RAID module might want to later */
153 void enable_kernel_vsx(void)
154 {
155 	WARN_ON(preemptible());
156 
157 #ifdef CONFIG_SMP
158 	if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
159 		giveup_vsx(current);
160 	else
161 		giveup_vsx(NULL);	/* just enable vsx for kernel - force */
162 #else
163 	giveup_vsx(last_task_used_vsx);
164 #endif /* CONFIG_SMP */
165 }
166 EXPORT_SYMBOL(enable_kernel_vsx);
167 #endif
168 
169 void giveup_vsx(struct task_struct *tsk)
170 {
171 	giveup_fpu(tsk);
172 	giveup_altivec(tsk);
173 	__giveup_vsx(tsk);
174 }
175 
176 void flush_vsx_to_thread(struct task_struct *tsk)
177 {
178 	if (tsk->thread.regs) {
179 		preempt_disable();
180 		if (tsk->thread.regs->msr & MSR_VSX) {
181 #ifdef CONFIG_SMP
182 			BUG_ON(tsk != current);
183 #endif
184 			giveup_vsx(tsk);
185 		}
186 		preempt_enable();
187 	}
188 }
189 #endif /* CONFIG_VSX */
190 
191 #ifdef CONFIG_SPE
192 
193 void enable_kernel_spe(void)
194 {
195 	WARN_ON(preemptible());
196 
197 #ifdef CONFIG_SMP
198 	if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
199 		giveup_spe(current);
200 	else
201 		giveup_spe(NULL);	/* just enable SPE for kernel - force */
202 #else
203 	giveup_spe(last_task_used_spe);
204 #endif /* __SMP __ */
205 }
206 EXPORT_SYMBOL(enable_kernel_spe);
207 
208 void flush_spe_to_thread(struct task_struct *tsk)
209 {
210 	if (tsk->thread.regs) {
211 		preempt_disable();
212 		if (tsk->thread.regs->msr & MSR_SPE) {
213 #ifdef CONFIG_SMP
214 			BUG_ON(tsk != current);
215 #endif
216 			giveup_spe(tsk);
217 		}
218 		preempt_enable();
219 	}
220 }
221 #endif /* CONFIG_SPE */
222 
223 #ifndef CONFIG_SMP
224 /*
225  * If we are doing lazy switching of CPU state (FP, altivec or SPE),
226  * and the current task has some state, discard it.
227  */
228 void discard_lazy_cpu_state(void)
229 {
230 	preempt_disable();
231 	if (last_task_used_math == current)
232 		last_task_used_math = NULL;
233 #ifdef CONFIG_ALTIVEC
234 	if (last_task_used_altivec == current)
235 		last_task_used_altivec = NULL;
236 #endif /* CONFIG_ALTIVEC */
237 #ifdef CONFIG_VSX
238 	if (last_task_used_vsx == current)
239 		last_task_used_vsx = NULL;
240 #endif /* CONFIG_VSX */
241 #ifdef CONFIG_SPE
242 	if (last_task_used_spe == current)
243 		last_task_used_spe = NULL;
244 #endif
245 	preempt_enable();
246 }
247 #endif /* CONFIG_SMP */
248 
249 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
250 void do_send_trap(struct pt_regs *regs, unsigned long address,
251 		  unsigned long error_code, int signal_code, int breakpt)
252 {
253 	siginfo_t info;
254 
255 	if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
256 			11, SIGSEGV) == NOTIFY_STOP)
257 		return;
258 
259 	/* Deliver the signal to userspace */
260 	info.si_signo = SIGTRAP;
261 	info.si_errno = breakpt;	/* breakpoint or watchpoint id */
262 	info.si_code = signal_code;
263 	info.si_addr = (void __user *)address;
264 	force_sig_info(SIGTRAP, &info, current);
265 }
266 #else	/* !CONFIG_PPC_ADV_DEBUG_REGS */
267 void do_dabr(struct pt_regs *regs, unsigned long address,
268 		    unsigned long error_code)
269 {
270 	siginfo_t info;
271 
272 	if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
273 			11, SIGSEGV) == NOTIFY_STOP)
274 		return;
275 
276 	if (debugger_dabr_match(regs))
277 		return;
278 
279 	/* Clear the DABR */
280 	set_dabr(0);
281 
282 	/* Deliver the signal to userspace */
283 	info.si_signo = SIGTRAP;
284 	info.si_errno = 0;
285 	info.si_code = TRAP_HWBKPT;
286 	info.si_addr = (void __user *)address;
287 	force_sig_info(SIGTRAP, &info, current);
288 }
289 #endif	/* CONFIG_PPC_ADV_DEBUG_REGS */
290 
291 static DEFINE_PER_CPU(unsigned long, current_dabr);
292 
293 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
294 /*
295  * Set the debug registers back to their default "safe" values.
296  */
297 static void set_debug_reg_defaults(struct thread_struct *thread)
298 {
299 	thread->iac1 = thread->iac2 = 0;
300 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
301 	thread->iac3 = thread->iac4 = 0;
302 #endif
303 	thread->dac1 = thread->dac2 = 0;
304 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
305 	thread->dvc1 = thread->dvc2 = 0;
306 #endif
307 	thread->dbcr0 = 0;
308 #ifdef CONFIG_BOOKE
309 	/*
310 	 * Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
311 	 */
312 	thread->dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |	\
313 			DBCR1_IAC3US | DBCR1_IAC4US;
314 	/*
315 	 * Force Data Address Compare User/Supervisor bits to be User-only
316 	 * (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
317 	 */
318 	thread->dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
319 #else
320 	thread->dbcr1 = 0;
321 #endif
322 }
323 
324 static void prime_debug_regs(struct thread_struct *thread)
325 {
326 	mtspr(SPRN_IAC1, thread->iac1);
327 	mtspr(SPRN_IAC2, thread->iac2);
328 #if CONFIG_PPC_ADV_DEBUG_IACS > 2
329 	mtspr(SPRN_IAC3, thread->iac3);
330 	mtspr(SPRN_IAC4, thread->iac4);
331 #endif
332 	mtspr(SPRN_DAC1, thread->dac1);
333 	mtspr(SPRN_DAC2, thread->dac2);
334 #if CONFIG_PPC_ADV_DEBUG_DVCS > 0
335 	mtspr(SPRN_DVC1, thread->dvc1);
336 	mtspr(SPRN_DVC2, thread->dvc2);
337 #endif
338 	mtspr(SPRN_DBCR0, thread->dbcr0);
339 	mtspr(SPRN_DBCR1, thread->dbcr1);
340 #ifdef CONFIG_BOOKE
341 	mtspr(SPRN_DBCR2, thread->dbcr2);
342 #endif
343 }
344 /*
345  * Unless neither the old or new thread are making use of the
346  * debug registers, set the debug registers from the values
347  * stored in the new thread.
348  */
349 static void switch_booke_debug_regs(struct thread_struct *new_thread)
350 {
351 	if ((current->thread.dbcr0 & DBCR0_IDM)
352 		|| (new_thread->dbcr0 & DBCR0_IDM))
353 			prime_debug_regs(new_thread);
354 }
355 #else	/* !CONFIG_PPC_ADV_DEBUG_REGS */
356 #ifndef CONFIG_HAVE_HW_BREAKPOINT
357 static void set_debug_reg_defaults(struct thread_struct *thread)
358 {
359 	if (thread->dabr) {
360 		thread->dabr = 0;
361 		set_dabr(0);
362 	}
363 }
364 #endif /* !CONFIG_HAVE_HW_BREAKPOINT */
365 #endif	/* CONFIG_PPC_ADV_DEBUG_REGS */
366 
367 int set_dabr(unsigned long dabr)
368 {
369 	__get_cpu_var(current_dabr) = dabr;
370 
371 	if (ppc_md.set_dabr)
372 		return ppc_md.set_dabr(dabr);
373 
374 	/* XXX should we have a CPU_FTR_HAS_DABR ? */
375 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
376 	mtspr(SPRN_DAC1, dabr);
377 #ifdef CONFIG_PPC_47x
378 	isync();
379 #endif
380 #elif defined(CONFIG_PPC_BOOK3S)
381 	mtspr(SPRN_DABR, dabr);
382 #endif
383 
384 
385 	return 0;
386 }
387 
388 #ifdef CONFIG_PPC64
389 DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
390 #endif
391 
392 struct task_struct *__switch_to(struct task_struct *prev,
393 	struct task_struct *new)
394 {
395 	struct thread_struct *new_thread, *old_thread;
396 	unsigned long flags;
397 	struct task_struct *last;
398 #ifdef CONFIG_PPC_BOOK3S_64
399 	struct ppc64_tlb_batch *batch;
400 #endif
401 
402 #ifdef CONFIG_SMP
403 	/* avoid complexity of lazy save/restore of fpu
404 	 * by just saving it every time we switch out if
405 	 * this task used the fpu during the last quantum.
406 	 *
407 	 * If it tries to use the fpu again, it'll trap and
408 	 * reload its fp regs.  So we don't have to do a restore
409 	 * every switch, just a save.
410 	 *  -- Cort
411 	 */
412 	if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
413 		giveup_fpu(prev);
414 #ifdef CONFIG_ALTIVEC
415 	/*
416 	 * If the previous thread used altivec in the last quantum
417 	 * (thus changing altivec regs) then save them.
418 	 * We used to check the VRSAVE register but not all apps
419 	 * set it, so we don't rely on it now (and in fact we need
420 	 * to save & restore VSCR even if VRSAVE == 0).  -- paulus
421 	 *
422 	 * On SMP we always save/restore altivec regs just to avoid the
423 	 * complexity of changing processors.
424 	 *  -- Cort
425 	 */
426 	if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
427 		giveup_altivec(prev);
428 #endif /* CONFIG_ALTIVEC */
429 #ifdef CONFIG_VSX
430 	if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
431 		/* VMX and FPU registers are already save here */
432 		__giveup_vsx(prev);
433 #endif /* CONFIG_VSX */
434 #ifdef CONFIG_SPE
435 	/*
436 	 * If the previous thread used spe in the last quantum
437 	 * (thus changing spe regs) then save them.
438 	 *
439 	 * On SMP we always save/restore spe regs just to avoid the
440 	 * complexity of changing processors.
441 	 */
442 	if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
443 		giveup_spe(prev);
444 #endif /* CONFIG_SPE */
445 
446 #else  /* CONFIG_SMP */
447 #ifdef CONFIG_ALTIVEC
448 	/* Avoid the trap.  On smp this this never happens since
449 	 * we don't set last_task_used_altivec -- Cort
450 	 */
451 	if (new->thread.regs && last_task_used_altivec == new)
452 		new->thread.regs->msr |= MSR_VEC;
453 #endif /* CONFIG_ALTIVEC */
454 #ifdef CONFIG_VSX
455 	if (new->thread.regs && last_task_used_vsx == new)
456 		new->thread.regs->msr |= MSR_VSX;
457 #endif /* CONFIG_VSX */
458 #ifdef CONFIG_SPE
459 	/* Avoid the trap.  On smp this this never happens since
460 	 * we don't set last_task_used_spe
461 	 */
462 	if (new->thread.regs && last_task_used_spe == new)
463 		new->thread.regs->msr |= MSR_SPE;
464 #endif /* CONFIG_SPE */
465 
466 #endif /* CONFIG_SMP */
467 
468 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
469 	switch_booke_debug_regs(&new->thread);
470 #else
471 /*
472  * For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
473  * schedule DABR
474  */
475 #ifndef CONFIG_HAVE_HW_BREAKPOINT
476 	if (unlikely(__get_cpu_var(current_dabr) != new->thread.dabr))
477 		set_dabr(new->thread.dabr);
478 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
479 #endif
480 
481 
482 	new_thread = &new->thread;
483 	old_thread = &current->thread;
484 
485 #if defined(CONFIG_PPC_BOOK3E_64)
486 	/* XXX Current Book3E code doesn't deal with kernel side DBCR0,
487 	 * we always hold the user values, so we set it now.
488 	 *
489 	 * However, we ensure the kernel MSR:DE is appropriately cleared too
490 	 * to avoid spurrious single step exceptions in the kernel.
491 	 *
492 	 * This will have to change to merge with the ppc32 code at some point,
493 	 * but I don't like much what ppc32 is doing today so there's some
494 	 * thinking needed there
495 	 */
496 	if ((new_thread->dbcr0 | old_thread->dbcr0) & DBCR0_IDM) {
497 		u32 dbcr0;
498 
499 		mtmsr(mfmsr() & ~MSR_DE);
500 		isync();
501 		dbcr0 = mfspr(SPRN_DBCR0);
502 		dbcr0 = (dbcr0 & DBCR0_EDM) | new_thread->dbcr0;
503 		mtspr(SPRN_DBCR0, dbcr0);
504 	}
505 #endif /* CONFIG_PPC64_BOOK3E */
506 
507 #ifdef CONFIG_PPC64
508 	/*
509 	 * Collect processor utilization data per process
510 	 */
511 	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
512 		struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
513 		long unsigned start_tb, current_tb;
514 		start_tb = old_thread->start_tb;
515 		cu->current_tb = current_tb = mfspr(SPRN_PURR);
516 		old_thread->accum_tb += (current_tb - start_tb);
517 		new_thread->start_tb = current_tb;
518 	}
519 #endif /* CONFIG_PPC64 */
520 
521 #ifdef CONFIG_PPC_BOOK3S_64
522 	batch = &__get_cpu_var(ppc64_tlb_batch);
523 	if (batch->active) {
524 		current_thread_info()->local_flags |= _TLF_LAZY_MMU;
525 		if (batch->index)
526 			__flush_tlb_pending(batch);
527 		batch->active = 0;
528 	}
529 #endif /* CONFIG_PPC_BOOK3S_64 */
530 
531 	local_irq_save(flags);
532 
533 	account_system_vtime(current);
534 	account_process_vtime(current);
535 
536 	/*
537 	 * We can't take a PMU exception inside _switch() since there is a
538 	 * window where the kernel stack SLB and the kernel stack are out
539 	 * of sync. Hard disable here.
540 	 */
541 	hard_irq_disable();
542 	last = _switch(old_thread, new_thread);
543 
544 #ifdef CONFIG_PPC_BOOK3S_64
545 	if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
546 		current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
547 		batch = &__get_cpu_var(ppc64_tlb_batch);
548 		batch->active = 1;
549 	}
550 #endif /* CONFIG_PPC_BOOK3S_64 */
551 
552 	local_irq_restore(flags);
553 
554 	return last;
555 }
556 
557 static int instructions_to_print = 16;
558 
559 static void show_instructions(struct pt_regs *regs)
560 {
561 	int i;
562 	unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
563 			sizeof(int));
564 
565 	printk("Instruction dump:");
566 
567 	for (i = 0; i < instructions_to_print; i++) {
568 		int instr;
569 
570 		if (!(i % 8))
571 			printk("\n");
572 
573 #if !defined(CONFIG_BOOKE)
574 		/* If executing with the IMMU off, adjust pc rather
575 		 * than print XXXXXXXX.
576 		 */
577 		if (!(regs->msr & MSR_IR))
578 			pc = (unsigned long)phys_to_virt(pc);
579 #endif
580 
581 		/* We use __get_user here *only* to avoid an OOPS on a
582 		 * bad address because the pc *should* only be a
583 		 * kernel address.
584 		 */
585 		if (!__kernel_text_address(pc) ||
586 		     __get_user(instr, (unsigned int __user *)pc)) {
587 			printk("XXXXXXXX ");
588 		} else {
589 			if (regs->nip == pc)
590 				printk("<%08x> ", instr);
591 			else
592 				printk("%08x ", instr);
593 		}
594 
595 		pc += sizeof(int);
596 	}
597 
598 	printk("\n");
599 }
600 
601 static struct regbit {
602 	unsigned long bit;
603 	const char *name;
604 } msr_bits[] = {
605 	{MSR_EE,	"EE"},
606 	{MSR_PR,	"PR"},
607 	{MSR_FP,	"FP"},
608 	{MSR_VEC,	"VEC"},
609 	{MSR_VSX,	"VSX"},
610 	{MSR_ME,	"ME"},
611 	{MSR_CE,	"CE"},
612 	{MSR_DE,	"DE"},
613 	{MSR_IR,	"IR"},
614 	{MSR_DR,	"DR"},
615 	{0,		NULL}
616 };
617 
618 static void printbits(unsigned long val, struct regbit *bits)
619 {
620 	const char *sep = "";
621 
622 	printk("<");
623 	for (; bits->bit; ++bits)
624 		if (val & bits->bit) {
625 			printk("%s%s", sep, bits->name);
626 			sep = ",";
627 		}
628 	printk(">");
629 }
630 
631 #ifdef CONFIG_PPC64
632 #define REG		"%016lx"
633 #define REGS_PER_LINE	4
634 #define LAST_VOLATILE	13
635 #else
636 #define REG		"%08lx"
637 #define REGS_PER_LINE	8
638 #define LAST_VOLATILE	12
639 #endif
640 
641 void show_regs(struct pt_regs * regs)
642 {
643 	int i, trap;
644 
645 	printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
646 	       regs->nip, regs->link, regs->ctr);
647 	printk("REGS: %p TRAP: %04lx   %s  (%s)\n",
648 	       regs, regs->trap, print_tainted(), init_utsname()->release);
649 	printk("MSR: "REG" ", regs->msr);
650 	printbits(regs->msr, msr_bits);
651 	printk("  CR: %08lx  XER: %08lx\n", regs->ccr, regs->xer);
652 	trap = TRAP(regs);
653 	if (trap == 0x300 || trap == 0x600)
654 #ifdef CONFIG_PPC_ADV_DEBUG_REGS
655 		printk("DEAR: "REG", ESR: "REG"\n", regs->dar, regs->dsisr);
656 #else
657 		printk("DAR: "REG", DSISR: %08lx\n", regs->dar, regs->dsisr);
658 #endif
659 	printk("TASK = %p[%d] '%s' THREAD: %p",
660 	       current, task_pid_nr(current), current->comm, task_thread_info(current));
661 
662 #ifdef CONFIG_SMP
663 	printk(" CPU: %d", raw_smp_processor_id());
664 #endif /* CONFIG_SMP */
665 
666 	for (i = 0;  i < 32;  i++) {
667 		if ((i % REGS_PER_LINE) == 0)
668 			printk("\nGPR%02d: ", i);
669 		printk(REG " ", regs->gpr[i]);
670 		if (i == LAST_VOLATILE && !FULL_REGS(regs))
671 			break;
672 	}
673 	printk("\n");
674 #ifdef CONFIG_KALLSYMS
675 	/*
676 	 * Lookup NIP late so we have the best change of getting the
677 	 * above info out without failing
678 	 */
679 	printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
680 	printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
681 #endif
682 	show_stack(current, (unsigned long *) regs->gpr[1]);
683 	if (!user_mode(regs))
684 		show_instructions(regs);
685 }
686 
687 void exit_thread(void)
688 {
689 	discard_lazy_cpu_state();
690 }
691 
692 void flush_thread(void)
693 {
694 	discard_lazy_cpu_state();
695 
696 #ifdef CONFIG_HAVE_HW_BREAKPOINT
697 	flush_ptrace_hw_breakpoint(current);
698 #else /* CONFIG_HAVE_HW_BREAKPOINT */
699 	set_debug_reg_defaults(&current->thread);
700 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
701 }
702 
703 void
704 release_thread(struct task_struct *t)
705 {
706 }
707 
708 /*
709  * This gets called before we allocate a new thread and copy
710  * the current task into it.
711  */
712 void prepare_to_copy(struct task_struct *tsk)
713 {
714 	flush_fp_to_thread(current);
715 	flush_altivec_to_thread(current);
716 	flush_vsx_to_thread(current);
717 	flush_spe_to_thread(current);
718 #ifdef CONFIG_HAVE_HW_BREAKPOINT
719 	flush_ptrace_hw_breakpoint(tsk);
720 #endif /* CONFIG_HAVE_HW_BREAKPOINT */
721 }
722 
723 /*
724  * Copy a thread..
725  */
726 extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
727 
728 int copy_thread(unsigned long clone_flags, unsigned long usp,
729 		unsigned long unused, struct task_struct *p,
730 		struct pt_regs *regs)
731 {
732 	struct pt_regs *childregs, *kregs;
733 	extern void ret_from_fork(void);
734 	unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
735 
736 	CHECK_FULL_REGS(regs);
737 	/* Copy registers */
738 	sp -= sizeof(struct pt_regs);
739 	childregs = (struct pt_regs *) sp;
740 	*childregs = *regs;
741 	if ((childregs->msr & MSR_PR) == 0) {
742 		/* for kernel thread, set `current' and stackptr in new task */
743 		childregs->gpr[1] = sp + sizeof(struct pt_regs);
744 #ifdef CONFIG_PPC32
745 		childregs->gpr[2] = (unsigned long) p;
746 #else
747 		clear_tsk_thread_flag(p, TIF_32BIT);
748 #endif
749 		p->thread.regs = NULL;	/* no user register state */
750 	} else {
751 		childregs->gpr[1] = usp;
752 		p->thread.regs = childregs;
753 		if (clone_flags & CLONE_SETTLS) {
754 #ifdef CONFIG_PPC64
755 			if (!is_32bit_task())
756 				childregs->gpr[13] = childregs->gpr[6];
757 			else
758 #endif
759 				childregs->gpr[2] = childregs->gpr[6];
760 		}
761 	}
762 	childregs->gpr[3] = 0;  /* Result from fork() */
763 	sp -= STACK_FRAME_OVERHEAD;
764 
765 	/*
766 	 * The way this works is that at some point in the future
767 	 * some task will call _switch to switch to the new task.
768 	 * That will pop off the stack frame created below and start
769 	 * the new task running at ret_from_fork.  The new task will
770 	 * do some house keeping and then return from the fork or clone
771 	 * system call, using the stack frame created above.
772 	 */
773 	sp -= sizeof(struct pt_regs);
774 	kregs = (struct pt_regs *) sp;
775 	sp -= STACK_FRAME_OVERHEAD;
776 	p->thread.ksp = sp;
777 	p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
778 				_ALIGN_UP(sizeof(struct thread_info), 16);
779 
780 #ifdef CONFIG_PPC_STD_MMU_64
781 	if (mmu_has_feature(MMU_FTR_SLB)) {
782 		unsigned long sp_vsid;
783 		unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
784 
785 		if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
786 			sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
787 				<< SLB_VSID_SHIFT_1T;
788 		else
789 			sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
790 				<< SLB_VSID_SHIFT;
791 		sp_vsid |= SLB_VSID_KERNEL | llp;
792 		p->thread.ksp_vsid = sp_vsid;
793 	}
794 #endif /* CONFIG_PPC_STD_MMU_64 */
795 #ifdef CONFIG_PPC64
796 	if (cpu_has_feature(CPU_FTR_DSCR)) {
797 		if (current->thread.dscr_inherit) {
798 			p->thread.dscr_inherit = 1;
799 			p->thread.dscr = current->thread.dscr;
800 		} else if (0 != dscr_default) {
801 			p->thread.dscr_inherit = 1;
802 			p->thread.dscr = dscr_default;
803 		} else {
804 			p->thread.dscr_inherit = 0;
805 			p->thread.dscr = 0;
806 		}
807 	}
808 #endif
809 
810 	/*
811 	 * The PPC64 ABI makes use of a TOC to contain function
812 	 * pointers.  The function (ret_from_except) is actually a pointer
813 	 * to the TOC entry.  The first entry is a pointer to the actual
814 	 * function.
815  	 */
816 #ifdef CONFIG_PPC64
817 	kregs->nip = *((unsigned long *)ret_from_fork);
818 #else
819 	kregs->nip = (unsigned long)ret_from_fork;
820 #endif
821 
822 	return 0;
823 }
824 
825 /*
826  * Set up a thread for executing a new program
827  */
828 void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
829 {
830 #ifdef CONFIG_PPC64
831 	unsigned long load_addr = regs->gpr[2];	/* saved by ELF_PLAT_INIT */
832 #endif
833 
834 	set_fs(USER_DS);
835 
836 	/*
837 	 * If we exec out of a kernel thread then thread.regs will not be
838 	 * set.  Do it now.
839 	 */
840 	if (!current->thread.regs) {
841 		struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
842 		current->thread.regs = regs - 1;
843 	}
844 
845 	memset(regs->gpr, 0, sizeof(regs->gpr));
846 	regs->ctr = 0;
847 	regs->link = 0;
848 	regs->xer = 0;
849 	regs->ccr = 0;
850 	regs->gpr[1] = sp;
851 
852 	/*
853 	 * We have just cleared all the nonvolatile GPRs, so make
854 	 * FULL_REGS(regs) return true.  This is necessary to allow
855 	 * ptrace to examine the thread immediately after exec.
856 	 */
857 	regs->trap &= ~1UL;
858 
859 #ifdef CONFIG_PPC32
860 	regs->mq = 0;
861 	regs->nip = start;
862 	regs->msr = MSR_USER;
863 #else
864 	if (!is_32bit_task()) {
865 		unsigned long entry, toc;
866 
867 		/* start is a relocated pointer to the function descriptor for
868 		 * the elf _start routine.  The first entry in the function
869 		 * descriptor is the entry address of _start and the second
870 		 * entry is the TOC value we need to use.
871 		 */
872 		__get_user(entry, (unsigned long __user *)start);
873 		__get_user(toc, (unsigned long __user *)start+1);
874 
875 		/* Check whether the e_entry function descriptor entries
876 		 * need to be relocated before we can use them.
877 		 */
878 		if (load_addr != 0) {
879 			entry += load_addr;
880 			toc   += load_addr;
881 		}
882 		regs->nip = entry;
883 		regs->gpr[2] = toc;
884 		regs->msr = MSR_USER64;
885 	} else {
886 		regs->nip = start;
887 		regs->gpr[2] = 0;
888 		regs->msr = MSR_USER32;
889 	}
890 #endif
891 
892 	discard_lazy_cpu_state();
893 #ifdef CONFIG_VSX
894 	current->thread.used_vsr = 0;
895 #endif
896 	memset(current->thread.fpr, 0, sizeof(current->thread.fpr));
897 	current->thread.fpscr.val = 0;
898 #ifdef CONFIG_ALTIVEC
899 	memset(current->thread.vr, 0, sizeof(current->thread.vr));
900 	memset(&current->thread.vscr, 0, sizeof(current->thread.vscr));
901 	current->thread.vscr.u[3] = 0x00010000; /* Java mode disabled */
902 	current->thread.vrsave = 0;
903 	current->thread.used_vr = 0;
904 #endif /* CONFIG_ALTIVEC */
905 #ifdef CONFIG_SPE
906 	memset(current->thread.evr, 0, sizeof(current->thread.evr));
907 	current->thread.acc = 0;
908 	current->thread.spefscr = 0;
909 	current->thread.used_spe = 0;
910 #endif /* CONFIG_SPE */
911 }
912 
913 #define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
914 		| PR_FP_EXC_RES | PR_FP_EXC_INV)
915 
916 int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
917 {
918 	struct pt_regs *regs = tsk->thread.regs;
919 
920 	/* This is a bit hairy.  If we are an SPE enabled  processor
921 	 * (have embedded fp) we store the IEEE exception enable flags in
922 	 * fpexc_mode.  fpexc_mode is also used for setting FP exception
923 	 * mode (asyn, precise, disabled) for 'Classic' FP. */
924 	if (val & PR_FP_EXC_SW_ENABLE) {
925 #ifdef CONFIG_SPE
926 		if (cpu_has_feature(CPU_FTR_SPE)) {
927 			tsk->thread.fpexc_mode = val &
928 				(PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
929 			return 0;
930 		} else {
931 			return -EINVAL;
932 		}
933 #else
934 		return -EINVAL;
935 #endif
936 	}
937 
938 	/* on a CONFIG_SPE this does not hurt us.  The bits that
939 	 * __pack_fe01 use do not overlap with bits used for
940 	 * PR_FP_EXC_SW_ENABLE.  Additionally, the MSR[FE0,FE1] bits
941 	 * on CONFIG_SPE implementations are reserved so writing to
942 	 * them does not change anything */
943 	if (val > PR_FP_EXC_PRECISE)
944 		return -EINVAL;
945 	tsk->thread.fpexc_mode = __pack_fe01(val);
946 	if (regs != NULL && (regs->msr & MSR_FP) != 0)
947 		regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
948 			| tsk->thread.fpexc_mode;
949 	return 0;
950 }
951 
952 int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
953 {
954 	unsigned int val;
955 
956 	if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
957 #ifdef CONFIG_SPE
958 		if (cpu_has_feature(CPU_FTR_SPE))
959 			val = tsk->thread.fpexc_mode;
960 		else
961 			return -EINVAL;
962 #else
963 		return -EINVAL;
964 #endif
965 	else
966 		val = __unpack_fe01(tsk->thread.fpexc_mode);
967 	return put_user(val, (unsigned int __user *) adr);
968 }
969 
970 int set_endian(struct task_struct *tsk, unsigned int val)
971 {
972 	struct pt_regs *regs = tsk->thread.regs;
973 
974 	if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
975 	    (val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
976 		return -EINVAL;
977 
978 	if (regs == NULL)
979 		return -EINVAL;
980 
981 	if (val == PR_ENDIAN_BIG)
982 		regs->msr &= ~MSR_LE;
983 	else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
984 		regs->msr |= MSR_LE;
985 	else
986 		return -EINVAL;
987 
988 	return 0;
989 }
990 
991 int get_endian(struct task_struct *tsk, unsigned long adr)
992 {
993 	struct pt_regs *regs = tsk->thread.regs;
994 	unsigned int val;
995 
996 	if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
997 	    !cpu_has_feature(CPU_FTR_REAL_LE))
998 		return -EINVAL;
999 
1000 	if (regs == NULL)
1001 		return -EINVAL;
1002 
1003 	if (regs->msr & MSR_LE) {
1004 		if (cpu_has_feature(CPU_FTR_REAL_LE))
1005 			val = PR_ENDIAN_LITTLE;
1006 		else
1007 			val = PR_ENDIAN_PPC_LITTLE;
1008 	} else
1009 		val = PR_ENDIAN_BIG;
1010 
1011 	return put_user(val, (unsigned int __user *)adr);
1012 }
1013 
1014 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
1015 {
1016 	tsk->thread.align_ctl = val;
1017 	return 0;
1018 }
1019 
1020 int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
1021 {
1022 	return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
1023 }
1024 
1025 #define TRUNC_PTR(x)	((typeof(x))(((unsigned long)(x)) & 0xffffffff))
1026 
1027 int sys_clone(unsigned long clone_flags, unsigned long usp,
1028 	      int __user *parent_tidp, void __user *child_threadptr,
1029 	      int __user *child_tidp, int p6,
1030 	      struct pt_regs *regs)
1031 {
1032 	CHECK_FULL_REGS(regs);
1033 	if (usp == 0)
1034 		usp = regs->gpr[1];	/* stack pointer for child */
1035 #ifdef CONFIG_PPC64
1036 	if (is_32bit_task()) {
1037 		parent_tidp = TRUNC_PTR(parent_tidp);
1038 		child_tidp = TRUNC_PTR(child_tidp);
1039 	}
1040 #endif
1041  	return do_fork(clone_flags, usp, regs, 0, parent_tidp, child_tidp);
1042 }
1043 
1044 int sys_fork(unsigned long p1, unsigned long p2, unsigned long p3,
1045 	     unsigned long p4, unsigned long p5, unsigned long p6,
1046 	     struct pt_regs *regs)
1047 {
1048 	CHECK_FULL_REGS(regs);
1049 	return do_fork(SIGCHLD, regs->gpr[1], regs, 0, NULL, NULL);
1050 }
1051 
1052 int sys_vfork(unsigned long p1, unsigned long p2, unsigned long p3,
1053 	      unsigned long p4, unsigned long p5, unsigned long p6,
1054 	      struct pt_regs *regs)
1055 {
1056 	CHECK_FULL_REGS(regs);
1057 	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->gpr[1],
1058 			regs, 0, NULL, NULL);
1059 }
1060 
1061 int sys_execve(unsigned long a0, unsigned long a1, unsigned long a2,
1062 	       unsigned long a3, unsigned long a4, unsigned long a5,
1063 	       struct pt_regs *regs)
1064 {
1065 	int error;
1066 	char *filename;
1067 
1068 	filename = getname((const char __user *) a0);
1069 	error = PTR_ERR(filename);
1070 	if (IS_ERR(filename))
1071 		goto out;
1072 	flush_fp_to_thread(current);
1073 	flush_altivec_to_thread(current);
1074 	flush_spe_to_thread(current);
1075 	error = do_execve(filename,
1076 			  (const char __user *const __user *) a1,
1077 			  (const char __user *const __user *) a2, regs);
1078 	putname(filename);
1079 out:
1080 	return error;
1081 }
1082 
1083 static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
1084 				  unsigned long nbytes)
1085 {
1086 	unsigned long stack_page;
1087 	unsigned long cpu = task_cpu(p);
1088 
1089 	/*
1090 	 * Avoid crashing if the stack has overflowed and corrupted
1091 	 * task_cpu(p), which is in the thread_info struct.
1092 	 */
1093 	if (cpu < NR_CPUS && cpu_possible(cpu)) {
1094 		stack_page = (unsigned long) hardirq_ctx[cpu];
1095 		if (sp >= stack_page + sizeof(struct thread_struct)
1096 		    && sp <= stack_page + THREAD_SIZE - nbytes)
1097 			return 1;
1098 
1099 		stack_page = (unsigned long) softirq_ctx[cpu];
1100 		if (sp >= stack_page + sizeof(struct thread_struct)
1101 		    && sp <= stack_page + THREAD_SIZE - nbytes)
1102 			return 1;
1103 	}
1104 	return 0;
1105 }
1106 
1107 int validate_sp(unsigned long sp, struct task_struct *p,
1108 		       unsigned long nbytes)
1109 {
1110 	unsigned long stack_page = (unsigned long)task_stack_page(p);
1111 
1112 	if (sp >= stack_page + sizeof(struct thread_struct)
1113 	    && sp <= stack_page + THREAD_SIZE - nbytes)
1114 		return 1;
1115 
1116 	return valid_irq_stack(sp, p, nbytes);
1117 }
1118 
1119 EXPORT_SYMBOL(validate_sp);
1120 
1121 unsigned long get_wchan(struct task_struct *p)
1122 {
1123 	unsigned long ip, sp;
1124 	int count = 0;
1125 
1126 	if (!p || p == current || p->state == TASK_RUNNING)
1127 		return 0;
1128 
1129 	sp = p->thread.ksp;
1130 	if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1131 		return 0;
1132 
1133 	do {
1134 		sp = *(unsigned long *)sp;
1135 		if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
1136 			return 0;
1137 		if (count > 0) {
1138 			ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
1139 			if (!in_sched_functions(ip))
1140 				return ip;
1141 		}
1142 	} while (count++ < 16);
1143 	return 0;
1144 }
1145 
1146 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
1147 
1148 void show_stack(struct task_struct *tsk, unsigned long *stack)
1149 {
1150 	unsigned long sp, ip, lr, newsp;
1151 	int count = 0;
1152 	int firstframe = 1;
1153 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1154 	int curr_frame = current->curr_ret_stack;
1155 	extern void return_to_handler(void);
1156 	unsigned long rth = (unsigned long)return_to_handler;
1157 	unsigned long mrth = -1;
1158 #ifdef CONFIG_PPC64
1159 	extern void mod_return_to_handler(void);
1160 	rth = *(unsigned long *)rth;
1161 	mrth = (unsigned long)mod_return_to_handler;
1162 	mrth = *(unsigned long *)mrth;
1163 #endif
1164 #endif
1165 
1166 	sp = (unsigned long) stack;
1167 	if (tsk == NULL)
1168 		tsk = current;
1169 	if (sp == 0) {
1170 		if (tsk == current)
1171 			asm("mr %0,1" : "=r" (sp));
1172 		else
1173 			sp = tsk->thread.ksp;
1174 	}
1175 
1176 	lr = 0;
1177 	printk("Call Trace:\n");
1178 	do {
1179 		if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
1180 			return;
1181 
1182 		stack = (unsigned long *) sp;
1183 		newsp = stack[0];
1184 		ip = stack[STACK_FRAME_LR_SAVE];
1185 		if (!firstframe || ip != lr) {
1186 			printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
1187 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1188 			if ((ip == rth || ip == mrth) && curr_frame >= 0) {
1189 				printk(" (%pS)",
1190 				       (void *)current->ret_stack[curr_frame].ret);
1191 				curr_frame--;
1192 			}
1193 #endif
1194 			if (firstframe)
1195 				printk(" (unreliable)");
1196 			printk("\n");
1197 		}
1198 		firstframe = 0;
1199 
1200 		/*
1201 		 * See if this is an exception frame.
1202 		 * We look for the "regshere" marker in the current frame.
1203 		 */
1204 		if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
1205 		    && stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
1206 			struct pt_regs *regs = (struct pt_regs *)
1207 				(sp + STACK_FRAME_OVERHEAD);
1208 			lr = regs->link;
1209 			printk("--- Exception: %lx at %pS\n    LR = %pS\n",
1210 			       regs->trap, (void *)regs->nip, (void *)lr);
1211 			firstframe = 1;
1212 		}
1213 
1214 		sp = newsp;
1215 	} while (count++ < kstack_depth_to_print);
1216 }
1217 
1218 void dump_stack(void)
1219 {
1220 	show_stack(current, NULL);
1221 }
1222 EXPORT_SYMBOL(dump_stack);
1223 
1224 #ifdef CONFIG_PPC64
1225 void ppc64_runlatch_on(void)
1226 {
1227 	unsigned long ctrl;
1228 
1229 	if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
1230 		HMT_medium();
1231 
1232 		ctrl = mfspr(SPRN_CTRLF);
1233 		ctrl |= CTRL_RUNLATCH;
1234 		mtspr(SPRN_CTRLT, ctrl);
1235 
1236 		set_thread_flag(TIF_RUNLATCH);
1237 	}
1238 }
1239 
1240 void __ppc64_runlatch_off(void)
1241 {
1242 	unsigned long ctrl;
1243 
1244 	HMT_medium();
1245 
1246 	clear_thread_flag(TIF_RUNLATCH);
1247 
1248 	ctrl = mfspr(SPRN_CTRLF);
1249 	ctrl &= ~CTRL_RUNLATCH;
1250 	mtspr(SPRN_CTRLT, ctrl);
1251 }
1252 #endif
1253 
1254 #if THREAD_SHIFT < PAGE_SHIFT
1255 
1256 static struct kmem_cache *thread_info_cache;
1257 
1258 struct thread_info *alloc_thread_info_node(struct task_struct *tsk, int node)
1259 {
1260 	struct thread_info *ti;
1261 
1262 	ti = kmem_cache_alloc_node(thread_info_cache, GFP_KERNEL, node);
1263 	if (unlikely(ti == NULL))
1264 		return NULL;
1265 #ifdef CONFIG_DEBUG_STACK_USAGE
1266 	memset(ti, 0, THREAD_SIZE);
1267 #endif
1268 	return ti;
1269 }
1270 
1271 void free_thread_info(struct thread_info *ti)
1272 {
1273 	kmem_cache_free(thread_info_cache, ti);
1274 }
1275 
1276 void thread_info_cache_init(void)
1277 {
1278 	thread_info_cache = kmem_cache_create("thread_info", THREAD_SIZE,
1279 					      THREAD_SIZE, 0, NULL);
1280 	BUG_ON(thread_info_cache == NULL);
1281 }
1282 
1283 #endif /* THREAD_SHIFT < PAGE_SHIFT */
1284 
1285 unsigned long arch_align_stack(unsigned long sp)
1286 {
1287 	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
1288 		sp -= get_random_int() & ~PAGE_MASK;
1289 	return sp & ~0xf;
1290 }
1291 
1292 static inline unsigned long brk_rnd(void)
1293 {
1294         unsigned long rnd = 0;
1295 
1296 	/* 8MB for 32bit, 1GB for 64bit */
1297 	if (is_32bit_task())
1298 		rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
1299 	else
1300 		rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
1301 
1302 	return rnd << PAGE_SHIFT;
1303 }
1304 
1305 unsigned long arch_randomize_brk(struct mm_struct *mm)
1306 {
1307 	unsigned long base = mm->brk;
1308 	unsigned long ret;
1309 
1310 #ifdef CONFIG_PPC_STD_MMU_64
1311 	/*
1312 	 * If we are using 1TB segments and we are allowed to randomise
1313 	 * the heap, we can put it above 1TB so it is backed by a 1TB
1314 	 * segment. Otherwise the heap will be in the bottom 1TB
1315 	 * which always uses 256MB segments and this may result in a
1316 	 * performance penalty.
1317 	 */
1318 	if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
1319 		base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
1320 #endif
1321 
1322 	ret = PAGE_ALIGN(base + brk_rnd());
1323 
1324 	if (ret < mm->brk)
1325 		return mm->brk;
1326 
1327 	return ret;
1328 }
1329 
1330 unsigned long randomize_et_dyn(unsigned long base)
1331 {
1332 	unsigned long ret = PAGE_ALIGN(base + brk_rnd());
1333 
1334 	if (ret < base)
1335 		return base;
1336 
1337 	return ret;
1338 }
1339