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v4.10.11
  1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 */
 14
 15#include <linux/sched.h>
 16#include <linux/preempt.h>
 17#include <linux/module.h>
 18#include <linux/fs.h>
 19#include <linux/kprobes.h>
 20#include <linux/elfcore.h>
 21#include <linux/tick.h>
 22#include <linux/init.h>
 23#include <linux/mm.h>
 24#include <linux/compat.h>
 25#include <linux/nmi.h>
 26#include <linux/syscalls.h>
 27#include <linux/kernel.h>
 28#include <linux/tracehook.h>
 29#include <linux/signal.h>
 30#include <linux/delay.h>
 31#include <linux/context_tracking.h>
 32#include <asm/stack.h>
 33#include <asm/switch_to.h>
 34#include <asm/homecache.h>
 35#include <asm/syscalls.h>
 36#include <asm/traps.h>
 37#include <asm/setup.h>
 38#include <linux/uaccess.h>
 39#ifdef CONFIG_HARDWALL
 40#include <asm/hardwall.h>
 41#endif
 42#include <arch/chip.h>
 43#include <arch/abi.h>
 44#include <arch/sim_def.h>
 45
 46/*
 47 * Use the (x86) "idle=poll" option to prefer low latency when leaving the
 48 * idle loop over low power while in the idle loop, e.g. if we have
 49 * one thread per core and we want to get threads out of futex waits fast.
 50 */
 51static int __init idle_setup(char *str)
 52{
 53	if (!str)
 54		return -EINVAL;
 55
 56	if (!strcmp(str, "poll")) {
 57		pr_info("using polling idle threads\n");
 58		cpu_idle_poll_ctrl(true);
 59		return 0;
 60	} else if (!strcmp(str, "halt")) {
 61		return 0;
 62	}
 63	return -1;
 64}
 65early_param("idle", idle_setup);
 66
 67void arch_cpu_idle(void)
 68{
 69	__this_cpu_write(irq_stat.idle_timestamp, jiffies);
 70	_cpu_idle();
 71}
 72
 73/*
 74 * Release a thread_info structure
 75 */
 76void arch_release_thread_stack(unsigned long *stack)
 77{
 78	struct thread_info *info = (void *)stack;
 79	struct single_step_state *step_state = info->step_state;
 80
 81	if (step_state) {
 82
 83		/*
 84		 * FIXME: we don't munmap step_state->buffer
 85		 * because the mm_struct for this process (info->task->mm)
 86		 * has already been zeroed in exit_mm().  Keeping a
 87		 * reference to it here seems like a bad move, so this
 88		 * means we can't munmap() the buffer, and therefore if we
 89		 * ptrace multiple threads in a process, we will slowly
 90		 * leak user memory.  (Note that as soon as the last
 91		 * thread in a process dies, we will reclaim all user
 92		 * memory including single-step buffers in the usual way.)
 93		 * We should either assign a kernel VA to this buffer
 94		 * somehow, or we should associate the buffer(s) with the
 95		 * mm itself so we can clean them up that way.
 96		 */
 97		kfree(step_state);
 98	}
 99}
100
101static void save_arch_state(struct thread_struct *t);
102
103int copy_thread(unsigned long clone_flags, unsigned long sp,
104		unsigned long arg, struct task_struct *p)
105{
106	struct pt_regs *childregs = task_pt_regs(p);
107	unsigned long ksp;
108	unsigned long *callee_regs;
109
110	/*
111	 * Set up the stack and stack pointer appropriately for the
112	 * new child to find itself woken up in __switch_to().
113	 * The callee-saved registers must be on the stack to be read;
114	 * the new task will then jump to assembly support to handle
115	 * calling schedule_tail(), etc., and (for userspace tasks)
116	 * returning to the context set up in the pt_regs.
117	 */
118	ksp = (unsigned long) childregs;
119	ksp -= C_ABI_SAVE_AREA_SIZE;   /* interrupt-entry save area */
120	((long *)ksp)[0] = ((long *)ksp)[1] = 0;
121	ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long);
122	callee_regs = (unsigned long *)ksp;
123	ksp -= C_ABI_SAVE_AREA_SIZE;   /* __switch_to() save area */
124	((long *)ksp)[0] = ((long *)ksp)[1] = 0;
125	p->thread.ksp = ksp;
126
127	/* Record the pid of the task that created this one. */
128	p->thread.creator_pid = current->pid;
129
130	if (unlikely(p->flags & PF_KTHREAD)) {
131		/* kernel thread */
132		memset(childregs, 0, sizeof(struct pt_regs));
133		memset(&callee_regs[2], 0,
134		       (CALLEE_SAVED_REGS_COUNT - 2) * sizeof(unsigned long));
135		callee_regs[0] = sp;   /* r30 = function */
136		callee_regs[1] = arg;  /* r31 = arg */
 
137		p->thread.pc = (unsigned long) ret_from_kernel_thread;
138		return 0;
139	}
140
141	/*
142	 * Start new thread in ret_from_fork so it schedules properly
143	 * and then return from interrupt like the parent.
144	 */
145	p->thread.pc = (unsigned long) ret_from_fork;
146
147	/*
148	 * Do not clone step state from the parent; each thread
149	 * must make its own lazily.
150	 */
151	task_thread_info(p)->step_state = NULL;
152
153#ifdef __tilegx__
154	/*
155	 * Do not clone unalign jit fixup from the parent; each thread
156	 * must allocate its own on demand.
157	 */
158	task_thread_info(p)->unalign_jit_base = NULL;
159#endif
160
161	/*
162	 * Copy the registers onto the kernel stack so the
163	 * return-from-interrupt code will reload it into registers.
164	 */
165	*childregs = *current_pt_regs();
166	childregs->regs[0] = 0;         /* return value is zero */
167	if (sp)
168		childregs->sp = sp;  /* override with new user stack pointer */
169	memcpy(callee_regs, &childregs->regs[CALLEE_SAVED_FIRST_REG],
170	       CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long));
171
172	/* Save user stack top pointer so we can ID the stack vm area later. */
173	p->thread.usp0 = childregs->sp;
174
175	/*
176	 * If CLONE_SETTLS is set, set "tp" in the new task to "r4",
177	 * which is passed in as arg #5 to sys_clone().
178	 */
179	if (clone_flags & CLONE_SETTLS)
180		childregs->tp = childregs->regs[4];
181
182
183#if CHIP_HAS_TILE_DMA()
184	/*
185	 * No DMA in the new thread.  We model this on the fact that
186	 * fork() clears the pending signals, alarms, and aio for the child.
187	 */
188	memset(&p->thread.tile_dma_state, 0, sizeof(struct tile_dma_state));
189	memset(&p->thread.dma_async_tlb, 0, sizeof(struct async_tlb));
190#endif
191
192	/* New thread has its miscellaneous processor state bits clear. */
193	p->thread.proc_status = 0;
194
195#ifdef CONFIG_HARDWALL
196	/* New thread does not own any networks. */
197	memset(&p->thread.hardwall[0], 0,
198	       sizeof(struct hardwall_task) * HARDWALL_TYPES);
199#endif
200
201
202	/*
203	 * Start the new thread with the current architecture state
204	 * (user interrupt masks, etc.).
205	 */
206	save_arch_state(&p->thread);
207
208	return 0;
209}
210
211int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
212{
213	task_thread_info(tsk)->align_ctl = val;
214	return 0;
215}
216
217int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
218{
219	return put_user(task_thread_info(tsk)->align_ctl,
220			(unsigned int __user *)adr);
221}
222
223static struct task_struct corrupt_current = { .comm = "<corrupt>" };
224
225/*
226 * Return "current" if it looks plausible, or else a pointer to a dummy.
227 * This can be helpful if we are just trying to emit a clean panic.
228 */
229struct task_struct *validate_current(void)
230{
231	struct task_struct *tsk = current;
232	if (unlikely((unsigned long)tsk < PAGE_OFFSET ||
233		     (high_memory && (void *)tsk > high_memory) ||
234		     ((unsigned long)tsk & (__alignof__(*tsk) - 1)) != 0)) {
235		pr_err("Corrupt 'current' %p (sp %#lx)\n", tsk, stack_pointer);
236		tsk = &corrupt_current;
237	}
238	return tsk;
239}
240
241/* Take and return the pointer to the previous task, for schedule_tail(). */
242struct task_struct *sim_notify_fork(struct task_struct *prev)
243{
244	struct task_struct *tsk = current;
245	__insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK_PARENT |
246		     (tsk->thread.creator_pid << _SIM_CONTROL_OPERATOR_BITS));
247	__insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK |
248		     (tsk->pid << _SIM_CONTROL_OPERATOR_BITS));
249	return prev;
250}
251
252int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
253{
254	struct pt_regs *ptregs = task_pt_regs(tsk);
255	elf_core_copy_regs(regs, ptregs);
256	return 1;
257}
258
259#if CHIP_HAS_TILE_DMA()
260
261/* Allow user processes to access the DMA SPRs */
262void grant_dma_mpls(void)
263{
264#if CONFIG_KERNEL_PL == 2
265	__insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
266	__insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
267#else
268	__insn_mtspr(SPR_MPL_DMA_CPL_SET_0, 1);
269	__insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_0, 1);
270#endif
271}
272
273/* Forbid user processes from accessing the DMA SPRs */
274void restrict_dma_mpls(void)
275{
276#if CONFIG_KERNEL_PL == 2
277	__insn_mtspr(SPR_MPL_DMA_CPL_SET_2, 1);
278	__insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_2, 1);
279#else
280	__insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
281	__insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
282#endif
283}
284
285/* Pause the DMA engine, then save off its state registers. */
286static void save_tile_dma_state(struct tile_dma_state *dma)
287{
288	unsigned long state = __insn_mfspr(SPR_DMA_USER_STATUS);
289	unsigned long post_suspend_state;
290
291	/* If we're running, suspend the engine. */
292	if ((state & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK)
293		__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK);
294
295	/*
296	 * Wait for the engine to idle, then save regs.  Note that we
297	 * want to record the "running" bit from before suspension,
298	 * and the "done" bit from after, so that we can properly
299	 * distinguish a case where the user suspended the engine from
300	 * the case where the kernel suspended as part of the context
301	 * swap.
302	 */
303	do {
304		post_suspend_state = __insn_mfspr(SPR_DMA_USER_STATUS);
305	} while (post_suspend_state & SPR_DMA_STATUS__BUSY_MASK);
306
307	dma->src = __insn_mfspr(SPR_DMA_SRC_ADDR);
308	dma->src_chunk = __insn_mfspr(SPR_DMA_SRC_CHUNK_ADDR);
309	dma->dest = __insn_mfspr(SPR_DMA_DST_ADDR);
310	dma->dest_chunk = __insn_mfspr(SPR_DMA_DST_CHUNK_ADDR);
311	dma->strides = __insn_mfspr(SPR_DMA_STRIDE);
312	dma->chunk_size = __insn_mfspr(SPR_DMA_CHUNK_SIZE);
313	dma->byte = __insn_mfspr(SPR_DMA_BYTE);
314	dma->status = (state & SPR_DMA_STATUS__RUNNING_MASK) |
315		(post_suspend_state & SPR_DMA_STATUS__DONE_MASK);
316}
317
318/* Restart a DMA that was running before we were context-switched out. */
319static void restore_tile_dma_state(struct thread_struct *t)
320{
321	const struct tile_dma_state *dma = &t->tile_dma_state;
322
323	/*
324	 * The only way to restore the done bit is to run a zero
325	 * length transaction.
326	 */
327	if ((dma->status & SPR_DMA_STATUS__DONE_MASK) &&
328	    !(__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__DONE_MASK)) {
329		__insn_mtspr(SPR_DMA_BYTE, 0);
330		__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
331		while (__insn_mfspr(SPR_DMA_USER_STATUS) &
332		       SPR_DMA_STATUS__BUSY_MASK)
333			;
334	}
335
336	__insn_mtspr(SPR_DMA_SRC_ADDR, dma->src);
337	__insn_mtspr(SPR_DMA_SRC_CHUNK_ADDR, dma->src_chunk);
338	__insn_mtspr(SPR_DMA_DST_ADDR, dma->dest);
339	__insn_mtspr(SPR_DMA_DST_CHUNK_ADDR, dma->dest_chunk);
340	__insn_mtspr(SPR_DMA_STRIDE, dma->strides);
341	__insn_mtspr(SPR_DMA_CHUNK_SIZE, dma->chunk_size);
342	__insn_mtspr(SPR_DMA_BYTE, dma->byte);
343
344	/*
345	 * Restart the engine if we were running and not done.
346	 * Clear a pending async DMA fault that we were waiting on return
347	 * to user space to execute, since we expect the DMA engine
348	 * to regenerate those faults for us now.  Note that we don't
349	 * try to clear the TIF_ASYNC_TLB flag, since it's relatively
350	 * harmless if set, and it covers both DMA and the SN processor.
351	 */
352	if ((dma->status & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) {
353		t->dma_async_tlb.fault_num = 0;
354		__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
355	}
356}
357
358#endif
359
360static void save_arch_state(struct thread_struct *t)
361{
362#if CHIP_HAS_SPLIT_INTR_MASK()
363	t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0_0) |
364		((u64)__insn_mfspr(SPR_INTERRUPT_MASK_0_1) << 32);
365#else
366	t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0);
367#endif
368	t->ex_context[0] = __insn_mfspr(SPR_EX_CONTEXT_0_0);
369	t->ex_context[1] = __insn_mfspr(SPR_EX_CONTEXT_0_1);
370	t->system_save[0] = __insn_mfspr(SPR_SYSTEM_SAVE_0_0);
371	t->system_save[1] = __insn_mfspr(SPR_SYSTEM_SAVE_0_1);
372	t->system_save[2] = __insn_mfspr(SPR_SYSTEM_SAVE_0_2);
373	t->system_save[3] = __insn_mfspr(SPR_SYSTEM_SAVE_0_3);
374	t->intctrl_0 = __insn_mfspr(SPR_INTCTRL_0_STATUS);
375	t->proc_status = __insn_mfspr(SPR_PROC_STATUS);
376#if !CHIP_HAS_FIXED_INTVEC_BASE()
377	t->interrupt_vector_base = __insn_mfspr(SPR_INTERRUPT_VECTOR_BASE_0);
378#endif
379	t->tile_rtf_hwm = __insn_mfspr(SPR_TILE_RTF_HWM);
380#if CHIP_HAS_DSTREAM_PF()
381	t->dstream_pf = __insn_mfspr(SPR_DSTREAM_PF);
382#endif
383}
384
385static void restore_arch_state(const struct thread_struct *t)
386{
387#if CHIP_HAS_SPLIT_INTR_MASK()
388	__insn_mtspr(SPR_INTERRUPT_MASK_0_0, (u32) t->interrupt_mask);
389	__insn_mtspr(SPR_INTERRUPT_MASK_0_1, t->interrupt_mask >> 32);
390#else
391	__insn_mtspr(SPR_INTERRUPT_MASK_0, t->interrupt_mask);
392#endif
393	__insn_mtspr(SPR_EX_CONTEXT_0_0, t->ex_context[0]);
394	__insn_mtspr(SPR_EX_CONTEXT_0_1, t->ex_context[1]);
395	__insn_mtspr(SPR_SYSTEM_SAVE_0_0, t->system_save[0]);
396	__insn_mtspr(SPR_SYSTEM_SAVE_0_1, t->system_save[1]);
397	__insn_mtspr(SPR_SYSTEM_SAVE_0_2, t->system_save[2]);
398	__insn_mtspr(SPR_SYSTEM_SAVE_0_3, t->system_save[3]);
399	__insn_mtspr(SPR_INTCTRL_0_STATUS, t->intctrl_0);
400	__insn_mtspr(SPR_PROC_STATUS, t->proc_status);
401#if !CHIP_HAS_FIXED_INTVEC_BASE()
402	__insn_mtspr(SPR_INTERRUPT_VECTOR_BASE_0, t->interrupt_vector_base);
403#endif
404	__insn_mtspr(SPR_TILE_RTF_HWM, t->tile_rtf_hwm);
405#if CHIP_HAS_DSTREAM_PF()
406	__insn_mtspr(SPR_DSTREAM_PF, t->dstream_pf);
407#endif
408}
409
410
411void _prepare_arch_switch(struct task_struct *next)
412{
413#if CHIP_HAS_TILE_DMA()
414	struct tile_dma_state *dma = &current->thread.tile_dma_state;
415	if (dma->enabled)
416		save_tile_dma_state(dma);
417#endif
418}
419
420
421struct task_struct *__sched _switch_to(struct task_struct *prev,
422				       struct task_struct *next)
423{
424	/* DMA state is already saved; save off other arch state. */
425	save_arch_state(&prev->thread);
426
427#if CHIP_HAS_TILE_DMA()
428	/*
429	 * Restore DMA in new task if desired.
430	 * Note that it is only safe to restart here since interrupts
431	 * are disabled, so we can't take any DMATLB miss or access
432	 * interrupts before we have finished switching stacks.
433	 */
434	if (next->thread.tile_dma_state.enabled) {
435		restore_tile_dma_state(&next->thread);
436		grant_dma_mpls();
437	} else {
438		restrict_dma_mpls();
439	}
440#endif
441
442	/* Restore other arch state. */
443	restore_arch_state(&next->thread);
444
445#ifdef CONFIG_HARDWALL
446	/* Enable or disable access to the network registers appropriately. */
447	hardwall_switch_tasks(prev, next);
448#endif
449
450	/* Notify the simulator of task exit. */
451	if (unlikely(prev->state == TASK_DEAD))
452		__insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_EXIT |
453			     (prev->pid << _SIM_CONTROL_OPERATOR_BITS));
454
455	/*
456	 * Switch kernel SP, PC, and callee-saved registers.
457	 * In the context of the new task, return the old task pointer
458	 * (i.e. the task that actually called __switch_to).
459	 * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp.
460	 */
461	return __switch_to(prev, next, next_current_ksp0(next));
462}
463
464/*
465 * This routine is called on return from interrupt if any of the
466 * TIF_ALLWORK_MASK flags are set in thread_info->flags.  It is
467 * entered with interrupts disabled so we don't miss an event that
468 * modified the thread_info flags.  We loop until all the tested flags
469 * are clear.  Note that the function is called on certain conditions
470 * that are not listed in the loop condition here (e.g. SINGLESTEP)
471 * which guarantees we will do those things once, and redo them if any
472 * of the other work items is re-done, but won't continue looping if
473 * all the other work is done.
 
 
 
474 */
475void prepare_exit_to_usermode(struct pt_regs *regs, u32 thread_info_flags)
476{
477	if (WARN_ON(!user_mode(regs)))
478		return;
479
480	do {
481		local_irq_enable();
482
483		if (thread_info_flags & _TIF_NEED_RESCHED)
484			schedule();
485
 
 
 
 
486#if CHIP_HAS_TILE_DMA()
487		if (thread_info_flags & _TIF_ASYNC_TLB)
488			do_async_page_fault(regs);
 
 
489#endif
490
491		if (thread_info_flags & _TIF_SIGPENDING)
492			do_signal(regs);
493
494		if (thread_info_flags & _TIF_NOTIFY_RESUME) {
495			clear_thread_flag(TIF_NOTIFY_RESUME);
496			tracehook_notify_resume(regs);
497		}
498
499		local_irq_disable();
500		thread_info_flags = READ_ONCE(current_thread_info()->flags);
501
502	} while (thread_info_flags & _TIF_WORK_MASK);
503
504	if (thread_info_flags & _TIF_SINGLESTEP) {
505		single_step_once(regs);
506#ifndef __tilegx__
507		/*
508		 * FIXME: on tilepro, since we enable interrupts in
509		 * this routine, it's possible that we miss a signal
510		 * or other asynchronous event.
511		 */
512		local_irq_disable();
513#endif
514	}
515
516	user_enter();
517}
518
519unsigned long get_wchan(struct task_struct *p)
520{
521	struct KBacktraceIterator kbt;
522
523	if (!p || p == current || p->state == TASK_RUNNING)
524		return 0;
525
526	for (KBacktraceIterator_init(&kbt, p, NULL);
527	     !KBacktraceIterator_end(&kbt);
528	     KBacktraceIterator_next(&kbt)) {
529		if (!in_sched_functions(kbt.it.pc))
530			return kbt.it.pc;
531	}
532
533	return 0;
534}
535
536/* Flush thread state. */
537void flush_thread(void)
538{
539	/* Nothing */
540}
541
542/*
543 * Free current thread data structures etc..
544 */
545void exit_thread(struct task_struct *tsk)
546{
547#ifdef CONFIG_HARDWALL
548	/*
549	 * Remove the task from the list of tasks that are associated
550	 * with any live hardwalls.  (If the task that is exiting held
551	 * the last reference to a hardwall fd, it would already have
552	 * been released and deactivated at this point.)
553	 */
554	hardwall_deactivate_all(tsk);
555#endif
556}
557
558void tile_show_regs(struct pt_regs *regs)
559{
 
560	int i;
 
 
 
 
561#ifdef __tilegx__
562	for (i = 0; i < 17; i++)
563		pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
564		       i, regs->regs[i], i+18, regs->regs[i+18],
565		       i+36, regs->regs[i+36]);
566	pr_err(" r17: "REGFMT" r35: "REGFMT" tp : "REGFMT"\n",
567	       regs->regs[17], regs->regs[35], regs->tp);
568	pr_err(" sp : "REGFMT" lr : "REGFMT"\n", regs->sp, regs->lr);
569#else
570	for (i = 0; i < 13; i++)
571		pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT
572		       " r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
573		       i, regs->regs[i], i+14, regs->regs[i+14],
574		       i+27, regs->regs[i+27], i+40, regs->regs[i+40]);
575	pr_err(" r13: "REGFMT" tp : "REGFMT" sp : "REGFMT" lr : "REGFMT"\n",
576	       regs->regs[13], regs->tp, regs->sp, regs->lr);
577#endif
578	pr_err(" pc : "REGFMT" ex1: %ld     faultnum: %ld flags:%s%s%s%s\n",
579	       regs->pc, regs->ex1, regs->faultnum,
580	       is_compat_task() ? " compat" : "",
581	       (regs->flags & PT_FLAGS_DISABLE_IRQ) ? " noirq" : "",
582	       !(regs->flags & PT_FLAGS_CALLER_SAVES) ? " nocallersave" : "",
583	       (regs->flags & PT_FLAGS_RESTORE_REGS) ? " restoreregs" : "");
584}
585
586void show_regs(struct pt_regs *regs)
587{
588	struct KBacktraceIterator kbt;
589
590	show_regs_print_info(KERN_DEFAULT);
591	tile_show_regs(regs);
592
593	KBacktraceIterator_init(&kbt, NULL, regs);
594	tile_show_stack(&kbt);
595}
596
597#ifdef __tilegx__
598void nmi_raise_cpu_backtrace(struct cpumask *in_mask)
599{
600	struct cpumask mask;
601	HV_Coord tile;
602	unsigned int timeout;
603	int cpu;
604	HV_NMI_Info info[NR_CPUS];
605
606	/* Tentatively dump stack on remote tiles via NMI. */
607	timeout = 100;
608	cpumask_copy(&mask, in_mask);
609	while (!cpumask_empty(&mask) && timeout) {
610		for_each_cpu(cpu, &mask) {
611			tile.x = cpu_x(cpu);
612			tile.y = cpu_y(cpu);
613			info[cpu] = hv_send_nmi(tile, TILE_NMI_DUMP_STACK, 0);
614			if (info[cpu].result == HV_NMI_RESULT_OK)
615				cpumask_clear_cpu(cpu, &mask);
616		}
617
618		mdelay(10);
619		touch_softlockup_watchdog();
620		timeout--;
621	}
622
623	/* Warn about cpus stuck in ICS. */
624	if (!cpumask_empty(&mask)) {
625		for_each_cpu(cpu, &mask) {
626
627			/* Clear the bit as if nmi_cpu_backtrace() ran. */
628			cpumask_clear_cpu(cpu, in_mask);
629
630			switch (info[cpu].result) {
631			case HV_NMI_RESULT_FAIL_ICS:
632				pr_warn("Skipping stack dump of cpu %d in ICS at pc %#llx\n",
633					cpu, info[cpu].pc);
634				break;
635			case HV_NMI_RESULT_FAIL_HV:
636				pr_warn("Skipping stack dump of cpu %d in hypervisor\n",
637					cpu);
638				break;
639			case HV_ENOSYS:
640				WARN_ONCE(1, "Hypervisor too old to allow remote stack dumps.\n");
641				break;
642			default:  /* should not happen */
643				pr_warn("Skipping stack dump of cpu %d [%d,%#llx]\n",
644					cpu, info[cpu].result, info[cpu].pc);
645				break;
646			}
647		}
648	}
649}
650
651void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
652{
653	nmi_trigger_cpumask_backtrace(mask, exclude_self,
654				      nmi_raise_cpu_backtrace);
655}
656#endif /* __tilegx_ */
v3.15
  1/*
  2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
  3 *
  4 *   This program is free software; you can redistribute it and/or
  5 *   modify it under the terms of the GNU General Public License
  6 *   as published by the Free Software Foundation, version 2.
  7 *
  8 *   This program is distributed in the hope that it will be useful, but
  9 *   WITHOUT ANY WARRANTY; without even the implied warranty of
 10 *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 11 *   NON INFRINGEMENT.  See the GNU General Public License for
 12 *   more details.
 13 */
 14
 15#include <linux/sched.h>
 16#include <linux/preempt.h>
 17#include <linux/module.h>
 18#include <linux/fs.h>
 19#include <linux/kprobes.h>
 20#include <linux/elfcore.h>
 21#include <linux/tick.h>
 22#include <linux/init.h>
 23#include <linux/mm.h>
 24#include <linux/compat.h>
 25#include <linux/hardirq.h>
 26#include <linux/syscalls.h>
 27#include <linux/kernel.h>
 28#include <linux/tracehook.h>
 29#include <linux/signal.h>
 
 
 30#include <asm/stack.h>
 31#include <asm/switch_to.h>
 32#include <asm/homecache.h>
 33#include <asm/syscalls.h>
 34#include <asm/traps.h>
 35#include <asm/setup.h>
 36#include <asm/uaccess.h>
 37#ifdef CONFIG_HARDWALL
 38#include <asm/hardwall.h>
 39#endif
 40#include <arch/chip.h>
 41#include <arch/abi.h>
 42#include <arch/sim_def.h>
 43
 44/*
 45 * Use the (x86) "idle=poll" option to prefer low latency when leaving the
 46 * idle loop over low power while in the idle loop, e.g. if we have
 47 * one thread per core and we want to get threads out of futex waits fast.
 48 */
 49static int __init idle_setup(char *str)
 50{
 51	if (!str)
 52		return -EINVAL;
 53
 54	if (!strcmp(str, "poll")) {
 55		pr_info("using polling idle threads.\n");
 56		cpu_idle_poll_ctrl(true);
 57		return 0;
 58	} else if (!strcmp(str, "halt")) {
 59		return 0;
 60	}
 61	return -1;
 62}
 63early_param("idle", idle_setup);
 64
 65void arch_cpu_idle(void)
 66{
 67	__get_cpu_var(irq_stat).idle_timestamp = jiffies;
 68	_cpu_idle();
 69}
 70
 71/*
 72 * Release a thread_info structure
 73 */
 74void arch_release_thread_info(struct thread_info *info)
 75{
 
 76	struct single_step_state *step_state = info->step_state;
 77
 78	if (step_state) {
 79
 80		/*
 81		 * FIXME: we don't munmap step_state->buffer
 82		 * because the mm_struct for this process (info->task->mm)
 83		 * has already been zeroed in exit_mm().  Keeping a
 84		 * reference to it here seems like a bad move, so this
 85		 * means we can't munmap() the buffer, and therefore if we
 86		 * ptrace multiple threads in a process, we will slowly
 87		 * leak user memory.  (Note that as soon as the last
 88		 * thread in a process dies, we will reclaim all user
 89		 * memory including single-step buffers in the usual way.)
 90		 * We should either assign a kernel VA to this buffer
 91		 * somehow, or we should associate the buffer(s) with the
 92		 * mm itself so we can clean them up that way.
 93		 */
 94		kfree(step_state);
 95	}
 96}
 97
 98static void save_arch_state(struct thread_struct *t);
 99
100int copy_thread(unsigned long clone_flags, unsigned long sp,
101		unsigned long arg, struct task_struct *p)
102{
103	struct pt_regs *childregs = task_pt_regs(p);
104	unsigned long ksp;
105	unsigned long *callee_regs;
106
107	/*
108	 * Set up the stack and stack pointer appropriately for the
109	 * new child to find itself woken up in __switch_to().
110	 * The callee-saved registers must be on the stack to be read;
111	 * the new task will then jump to assembly support to handle
112	 * calling schedule_tail(), etc., and (for userspace tasks)
113	 * returning to the context set up in the pt_regs.
114	 */
115	ksp = (unsigned long) childregs;
116	ksp -= C_ABI_SAVE_AREA_SIZE;   /* interrupt-entry save area */
117	((long *)ksp)[0] = ((long *)ksp)[1] = 0;
118	ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long);
119	callee_regs = (unsigned long *)ksp;
120	ksp -= C_ABI_SAVE_AREA_SIZE;   /* __switch_to() save area */
121	((long *)ksp)[0] = ((long *)ksp)[1] = 0;
122	p->thread.ksp = ksp;
123
124	/* Record the pid of the task that created this one. */
125	p->thread.creator_pid = current->pid;
126
127	if (unlikely(p->flags & PF_KTHREAD)) {
128		/* kernel thread */
129		memset(childregs, 0, sizeof(struct pt_regs));
130		memset(&callee_regs[2], 0,
131		       (CALLEE_SAVED_REGS_COUNT - 2) * sizeof(unsigned long));
132		callee_regs[0] = sp;   /* r30 = function */
133		callee_regs[1] = arg;  /* r31 = arg */
134		childregs->ex1 = PL_ICS_EX1(KERNEL_PL, 0);
135		p->thread.pc = (unsigned long) ret_from_kernel_thread;
136		return 0;
137	}
138
139	/*
140	 * Start new thread in ret_from_fork so it schedules properly
141	 * and then return from interrupt like the parent.
142	 */
143	p->thread.pc = (unsigned long) ret_from_fork;
144
145	/*
146	 * Do not clone step state from the parent; each thread
147	 * must make its own lazily.
148	 */
149	task_thread_info(p)->step_state = NULL;
150
151#ifdef __tilegx__
152	/*
153	 * Do not clone unalign jit fixup from the parent; each thread
154	 * must allocate its own on demand.
155	 */
156	task_thread_info(p)->unalign_jit_base = NULL;
157#endif
158
159	/*
160	 * Copy the registers onto the kernel stack so the
161	 * return-from-interrupt code will reload it into registers.
162	 */
163	*childregs = *current_pt_regs();
164	childregs->regs[0] = 0;         /* return value is zero */
165	if (sp)
166		childregs->sp = sp;  /* override with new user stack pointer */
167	memcpy(callee_regs, &childregs->regs[CALLEE_SAVED_FIRST_REG],
168	       CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long));
169
170	/* Save user stack top pointer so we can ID the stack vm area later. */
171	p->thread.usp0 = childregs->sp;
172
173	/*
174	 * If CLONE_SETTLS is set, set "tp" in the new task to "r4",
175	 * which is passed in as arg #5 to sys_clone().
176	 */
177	if (clone_flags & CLONE_SETTLS)
178		childregs->tp = childregs->regs[4];
179
180
181#if CHIP_HAS_TILE_DMA()
182	/*
183	 * No DMA in the new thread.  We model this on the fact that
184	 * fork() clears the pending signals, alarms, and aio for the child.
185	 */
186	memset(&p->thread.tile_dma_state, 0, sizeof(struct tile_dma_state));
187	memset(&p->thread.dma_async_tlb, 0, sizeof(struct async_tlb));
188#endif
189
190	/* New thread has its miscellaneous processor state bits clear. */
191	p->thread.proc_status = 0;
192
193#ifdef CONFIG_HARDWALL
194	/* New thread does not own any networks. */
195	memset(&p->thread.hardwall[0], 0,
196	       sizeof(struct hardwall_task) * HARDWALL_TYPES);
197#endif
198
199
200	/*
201	 * Start the new thread with the current architecture state
202	 * (user interrupt masks, etc.).
203	 */
204	save_arch_state(&p->thread);
205
206	return 0;
207}
208
209int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
210{
211	task_thread_info(tsk)->align_ctl = val;
212	return 0;
213}
214
215int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
216{
217	return put_user(task_thread_info(tsk)->align_ctl,
218			(unsigned int __user *)adr);
219}
220
221static struct task_struct corrupt_current = { .comm = "<corrupt>" };
222
223/*
224 * Return "current" if it looks plausible, or else a pointer to a dummy.
225 * This can be helpful if we are just trying to emit a clean panic.
226 */
227struct task_struct *validate_current(void)
228{
229	struct task_struct *tsk = current;
230	if (unlikely((unsigned long)tsk < PAGE_OFFSET ||
231		     (high_memory && (void *)tsk > high_memory) ||
232		     ((unsigned long)tsk & (__alignof__(*tsk) - 1)) != 0)) {
233		pr_err("Corrupt 'current' %p (sp %#lx)\n", tsk, stack_pointer);
234		tsk = &corrupt_current;
235	}
236	return tsk;
237}
238
239/* Take and return the pointer to the previous task, for schedule_tail(). */
240struct task_struct *sim_notify_fork(struct task_struct *prev)
241{
242	struct task_struct *tsk = current;
243	__insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK_PARENT |
244		     (tsk->thread.creator_pid << _SIM_CONTROL_OPERATOR_BITS));
245	__insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK |
246		     (tsk->pid << _SIM_CONTROL_OPERATOR_BITS));
247	return prev;
248}
249
250int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
251{
252	struct pt_regs *ptregs = task_pt_regs(tsk);
253	elf_core_copy_regs(regs, ptregs);
254	return 1;
255}
256
257#if CHIP_HAS_TILE_DMA()
258
259/* Allow user processes to access the DMA SPRs */
260void grant_dma_mpls(void)
261{
262#if CONFIG_KERNEL_PL == 2
263	__insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
264	__insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
265#else
266	__insn_mtspr(SPR_MPL_DMA_CPL_SET_0, 1);
267	__insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_0, 1);
268#endif
269}
270
271/* Forbid user processes from accessing the DMA SPRs */
272void restrict_dma_mpls(void)
273{
274#if CONFIG_KERNEL_PL == 2
275	__insn_mtspr(SPR_MPL_DMA_CPL_SET_2, 1);
276	__insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_2, 1);
277#else
278	__insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
279	__insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
280#endif
281}
282
283/* Pause the DMA engine, then save off its state registers. */
284static void save_tile_dma_state(struct tile_dma_state *dma)
285{
286	unsigned long state = __insn_mfspr(SPR_DMA_USER_STATUS);
287	unsigned long post_suspend_state;
288
289	/* If we're running, suspend the engine. */
290	if ((state & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK)
291		__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK);
292
293	/*
294	 * Wait for the engine to idle, then save regs.  Note that we
295	 * want to record the "running" bit from before suspension,
296	 * and the "done" bit from after, so that we can properly
297	 * distinguish a case where the user suspended the engine from
298	 * the case where the kernel suspended as part of the context
299	 * swap.
300	 */
301	do {
302		post_suspend_state = __insn_mfspr(SPR_DMA_USER_STATUS);
303	} while (post_suspend_state & SPR_DMA_STATUS__BUSY_MASK);
304
305	dma->src = __insn_mfspr(SPR_DMA_SRC_ADDR);
306	dma->src_chunk = __insn_mfspr(SPR_DMA_SRC_CHUNK_ADDR);
307	dma->dest = __insn_mfspr(SPR_DMA_DST_ADDR);
308	dma->dest_chunk = __insn_mfspr(SPR_DMA_DST_CHUNK_ADDR);
309	dma->strides = __insn_mfspr(SPR_DMA_STRIDE);
310	dma->chunk_size = __insn_mfspr(SPR_DMA_CHUNK_SIZE);
311	dma->byte = __insn_mfspr(SPR_DMA_BYTE);
312	dma->status = (state & SPR_DMA_STATUS__RUNNING_MASK) |
313		(post_suspend_state & SPR_DMA_STATUS__DONE_MASK);
314}
315
316/* Restart a DMA that was running before we were context-switched out. */
317static void restore_tile_dma_state(struct thread_struct *t)
318{
319	const struct tile_dma_state *dma = &t->tile_dma_state;
320
321	/*
322	 * The only way to restore the done bit is to run a zero
323	 * length transaction.
324	 */
325	if ((dma->status & SPR_DMA_STATUS__DONE_MASK) &&
326	    !(__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__DONE_MASK)) {
327		__insn_mtspr(SPR_DMA_BYTE, 0);
328		__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
329		while (__insn_mfspr(SPR_DMA_USER_STATUS) &
330		       SPR_DMA_STATUS__BUSY_MASK)
331			;
332	}
333
334	__insn_mtspr(SPR_DMA_SRC_ADDR, dma->src);
335	__insn_mtspr(SPR_DMA_SRC_CHUNK_ADDR, dma->src_chunk);
336	__insn_mtspr(SPR_DMA_DST_ADDR, dma->dest);
337	__insn_mtspr(SPR_DMA_DST_CHUNK_ADDR, dma->dest_chunk);
338	__insn_mtspr(SPR_DMA_STRIDE, dma->strides);
339	__insn_mtspr(SPR_DMA_CHUNK_SIZE, dma->chunk_size);
340	__insn_mtspr(SPR_DMA_BYTE, dma->byte);
341
342	/*
343	 * Restart the engine if we were running and not done.
344	 * Clear a pending async DMA fault that we were waiting on return
345	 * to user space to execute, since we expect the DMA engine
346	 * to regenerate those faults for us now.  Note that we don't
347	 * try to clear the TIF_ASYNC_TLB flag, since it's relatively
348	 * harmless if set, and it covers both DMA and the SN processor.
349	 */
350	if ((dma->status & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) {
351		t->dma_async_tlb.fault_num = 0;
352		__insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
353	}
354}
355
356#endif
357
358static void save_arch_state(struct thread_struct *t)
359{
360#if CHIP_HAS_SPLIT_INTR_MASK()
361	t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0_0) |
362		((u64)__insn_mfspr(SPR_INTERRUPT_MASK_0_1) << 32);
363#else
364	t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0);
365#endif
366	t->ex_context[0] = __insn_mfspr(SPR_EX_CONTEXT_0_0);
367	t->ex_context[1] = __insn_mfspr(SPR_EX_CONTEXT_0_1);
368	t->system_save[0] = __insn_mfspr(SPR_SYSTEM_SAVE_0_0);
369	t->system_save[1] = __insn_mfspr(SPR_SYSTEM_SAVE_0_1);
370	t->system_save[2] = __insn_mfspr(SPR_SYSTEM_SAVE_0_2);
371	t->system_save[3] = __insn_mfspr(SPR_SYSTEM_SAVE_0_3);
372	t->intctrl_0 = __insn_mfspr(SPR_INTCTRL_0_STATUS);
373	t->proc_status = __insn_mfspr(SPR_PROC_STATUS);
374#if !CHIP_HAS_FIXED_INTVEC_BASE()
375	t->interrupt_vector_base = __insn_mfspr(SPR_INTERRUPT_VECTOR_BASE_0);
376#endif
377	t->tile_rtf_hwm = __insn_mfspr(SPR_TILE_RTF_HWM);
378#if CHIP_HAS_DSTREAM_PF()
379	t->dstream_pf = __insn_mfspr(SPR_DSTREAM_PF);
380#endif
381}
382
383static void restore_arch_state(const struct thread_struct *t)
384{
385#if CHIP_HAS_SPLIT_INTR_MASK()
386	__insn_mtspr(SPR_INTERRUPT_MASK_0_0, (u32) t->interrupt_mask);
387	__insn_mtspr(SPR_INTERRUPT_MASK_0_1, t->interrupt_mask >> 32);
388#else
389	__insn_mtspr(SPR_INTERRUPT_MASK_0, t->interrupt_mask);
390#endif
391	__insn_mtspr(SPR_EX_CONTEXT_0_0, t->ex_context[0]);
392	__insn_mtspr(SPR_EX_CONTEXT_0_1, t->ex_context[1]);
393	__insn_mtspr(SPR_SYSTEM_SAVE_0_0, t->system_save[0]);
394	__insn_mtspr(SPR_SYSTEM_SAVE_0_1, t->system_save[1]);
395	__insn_mtspr(SPR_SYSTEM_SAVE_0_2, t->system_save[2]);
396	__insn_mtspr(SPR_SYSTEM_SAVE_0_3, t->system_save[3]);
397	__insn_mtspr(SPR_INTCTRL_0_STATUS, t->intctrl_0);
398	__insn_mtspr(SPR_PROC_STATUS, t->proc_status);
399#if !CHIP_HAS_FIXED_INTVEC_BASE()
400	__insn_mtspr(SPR_INTERRUPT_VECTOR_BASE_0, t->interrupt_vector_base);
401#endif
402	__insn_mtspr(SPR_TILE_RTF_HWM, t->tile_rtf_hwm);
403#if CHIP_HAS_DSTREAM_PF()
404	__insn_mtspr(SPR_DSTREAM_PF, t->dstream_pf);
405#endif
406}
407
408
409void _prepare_arch_switch(struct task_struct *next)
410{
411#if CHIP_HAS_TILE_DMA()
412	struct tile_dma_state *dma = &current->thread.tile_dma_state;
413	if (dma->enabled)
414		save_tile_dma_state(dma);
415#endif
416}
417
418
419struct task_struct *__sched _switch_to(struct task_struct *prev,
420				       struct task_struct *next)
421{
422	/* DMA state is already saved; save off other arch state. */
423	save_arch_state(&prev->thread);
424
425#if CHIP_HAS_TILE_DMA()
426	/*
427	 * Restore DMA in new task if desired.
428	 * Note that it is only safe to restart here since interrupts
429	 * are disabled, so we can't take any DMATLB miss or access
430	 * interrupts before we have finished switching stacks.
431	 */
432	if (next->thread.tile_dma_state.enabled) {
433		restore_tile_dma_state(&next->thread);
434		grant_dma_mpls();
435	} else {
436		restrict_dma_mpls();
437	}
438#endif
439
440	/* Restore other arch state. */
441	restore_arch_state(&next->thread);
442
443#ifdef CONFIG_HARDWALL
444	/* Enable or disable access to the network registers appropriately. */
445	hardwall_switch_tasks(prev, next);
446#endif
447
 
 
 
 
 
448	/*
449	 * Switch kernel SP, PC, and callee-saved registers.
450	 * In the context of the new task, return the old task pointer
451	 * (i.e. the task that actually called __switch_to).
452	 * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp.
453	 */
454	return __switch_to(prev, next, next_current_ksp0(next));
455}
456
457/*
458 * This routine is called on return from interrupt if any of the
459 * TIF_WORK_MASK flags are set in thread_info->flags.  It is
460 * entered with interrupts disabled so we don't miss an event
461 * that modified the thread_info flags.  If any flag is set, we
462 * handle it and return, and the calling assembly code will
463 * re-disable interrupts, reload the thread flags, and call back
464 * if more flags need to be handled.
465 *
466 * We return whether we need to check the thread_info flags again
467 * or not.  Note that we don't clear TIF_SINGLESTEP here, so it's
468 * important that it be tested last, and then claim that we don't
469 * need to recheck the flags.
470 */
471int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)
472{
473	/* If we enter in kernel mode, do nothing and exit the caller loop. */
474	if (!user_mode(regs))
475		return 0;
 
 
476
477	/* Enable interrupts; they are disabled again on return to caller. */
478	local_irq_enable();
479
480	if (thread_info_flags & _TIF_NEED_RESCHED) {
481		schedule();
482		return 1;
483	}
484#if CHIP_HAS_TILE_DMA()
485	if (thread_info_flags & _TIF_ASYNC_TLB) {
486		do_async_page_fault(regs);
487		return 1;
488	}
489#endif
490	if (thread_info_flags & _TIF_SIGPENDING) {
491		do_signal(regs);
492		return 1;
493	}
494	if (thread_info_flags & _TIF_NOTIFY_RESUME) {
495		clear_thread_flag(TIF_NOTIFY_RESUME);
496		tracehook_notify_resume(regs);
497		return 1;
498	}
 
 
 
 
 
499	if (thread_info_flags & _TIF_SINGLESTEP) {
500		single_step_once(regs);
501		return 0;
 
 
 
 
 
 
 
502	}
503	panic("work_pending: bad flags %#x\n", thread_info_flags);
 
504}
505
506unsigned long get_wchan(struct task_struct *p)
507{
508	struct KBacktraceIterator kbt;
509
510	if (!p || p == current || p->state == TASK_RUNNING)
511		return 0;
512
513	for (KBacktraceIterator_init(&kbt, p, NULL);
514	     !KBacktraceIterator_end(&kbt);
515	     KBacktraceIterator_next(&kbt)) {
516		if (!in_sched_functions(kbt.it.pc))
517			return kbt.it.pc;
518	}
519
520	return 0;
521}
522
523/* Flush thread state. */
524void flush_thread(void)
525{
526	/* Nothing */
527}
528
529/*
530 * Free current thread data structures etc..
531 */
532void exit_thread(void)
533{
534#ifdef CONFIG_HARDWALL
535	/*
536	 * Remove the task from the list of tasks that are associated
537	 * with any live hardwalls.  (If the task that is exiting held
538	 * the last reference to a hardwall fd, it would already have
539	 * been released and deactivated at this point.)
540	 */
541	hardwall_deactivate_all(current);
542#endif
543}
544
545void show_regs(struct pt_regs *regs)
546{
547	struct task_struct *tsk = validate_current();
548	int i;
549
550	pr_err("\n");
551	if (tsk != &corrupt_current)
552		show_regs_print_info(KERN_ERR);
553#ifdef __tilegx__
554	for (i = 0; i < 17; i++)
555		pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
556		       i, regs->regs[i], i+18, regs->regs[i+18],
557		       i+36, regs->regs[i+36]);
558	pr_err(" r17: "REGFMT" r35: "REGFMT" tp : "REGFMT"\n",
559	       regs->regs[17], regs->regs[35], regs->tp);
560	pr_err(" sp : "REGFMT" lr : "REGFMT"\n", regs->sp, regs->lr);
561#else
562	for (i = 0; i < 13; i++)
563		pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT
564		       " r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
565		       i, regs->regs[i], i+14, regs->regs[i+14],
566		       i+27, regs->regs[i+27], i+40, regs->regs[i+40]);
567	pr_err(" r13: "REGFMT" tp : "REGFMT" sp : "REGFMT" lr : "REGFMT"\n",
568	       regs->regs[13], regs->tp, regs->sp, regs->lr);
569#endif
570	pr_err(" pc : "REGFMT" ex1: %ld     faultnum: %ld\n",
571	       regs->pc, regs->ex1, regs->faultnum);
 
 
 
 
 
 
 
 
 
 
 
 
572
573	dump_stack_regs(regs);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
574}