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TOMOYO Linux Cross Reference
Linux/arch/tile/kernel/process.c

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  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  */
 51 static 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 }
 65 early_param("idle", idle_setup);
 66 
 67 void 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  */
 76 void 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 
101 static void save_arch_state(struct thread_struct *t);
102 
103 int 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 
211 int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
212 {
213         task_thread_info(tsk)->align_ctl = val;
214         return 0;
215 }
216 
217 int 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 
223 static 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  */
229 struct 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(). */
242 struct 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 
252 int 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 */
262 void 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 */
274 void 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. */
286 static 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. */
319 static 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 
360 static 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 
385 static 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 
411 void _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 
421 struct 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  */
475 void 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 
519 unsigned 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. */
537 void flush_thread(void)
538 {
539         /* Nothing */
540 }
541 
542 /*
543  * Free current thread data structures etc..
544  */
545 void 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 
558 void 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 
586 void 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__
598 void 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 
651 void 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_ */
657 

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