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 #ifdef CONFIG_HARDWALL
37 #include <asm/hardwall.h>
38 #endif
39 #include <arch/chip.h>
40 #include <arch/abi.h>
41 #include <arch/sim_def.h>
42
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 */
49 static int no_idle_nap;
idle_setup(char * str)50 static int __init idle_setup(char *str)
51 {
52 if (!str)
53 return -EINVAL;
54
55 if (!strcmp(str, "poll")) {
56 pr_info("using polling idle threads.\n");
57 no_idle_nap = 1;
58 } else if (!strcmp(str, "halt"))
59 no_idle_nap = 0;
60 else
61 return -1;
62
63 return 0;
64 }
65 early_param("idle", idle_setup);
66
67 /*
68 * The idle thread. There's no useful work to be
69 * done, so just try to conserve power and have a
70 * low exit latency (ie sit in a loop waiting for
71 * somebody to say that they'd like to reschedule)
72 */
cpu_idle(void)73 void cpu_idle(void)
74 {
75 int cpu = smp_processor_id();
76
77
78 current_thread_info()->status |= TS_POLLING;
79
80 if (no_idle_nap) {
81 while (1) {
82 while (!need_resched())
83 cpu_relax();
84 schedule();
85 }
86 }
87
88 /* endless idle loop with no priority at all */
89 while (1) {
90 tick_nohz_idle_enter();
91 rcu_idle_enter();
92 while (!need_resched()) {
93 if (cpu_is_offline(cpu))
94 BUG(); /* no HOTPLUG_CPU */
95
96 local_irq_disable();
97 __get_cpu_var(irq_stat).idle_timestamp = jiffies;
98 current_thread_info()->status &= ~TS_POLLING;
99 /*
100 * TS_POLLING-cleared state must be visible before we
101 * test NEED_RESCHED:
102 */
103 smp_mb();
104
105 if (!need_resched())
106 _cpu_idle();
107 else
108 local_irq_enable();
109 current_thread_info()->status |= TS_POLLING;
110 }
111 rcu_idle_exit();
112 tick_nohz_idle_exit();
113 schedule_preempt_disabled();
114 }
115 }
116
alloc_thread_info_node(struct task_struct * task,int node)117 struct thread_info *alloc_thread_info_node(struct task_struct *task, int node)
118 {
119 struct page *page;
120 gfp_t flags = GFP_KERNEL;
121
122 #ifdef CONFIG_DEBUG_STACK_USAGE
123 flags |= __GFP_ZERO;
124 #endif
125
126 page = alloc_pages_node(node, flags, THREAD_SIZE_ORDER);
127 if (!page)
128 return NULL;
129
130 return (struct thread_info *)page_address(page);
131 }
132
133 /*
134 * Free a thread_info node, and all of its derivative
135 * data structures.
136 */
free_thread_info(struct thread_info * info)137 void free_thread_info(struct thread_info *info)
138 {
139 struct single_step_state *step_state = info->step_state;
140
141 #ifdef CONFIG_HARDWALL
142 /*
143 * We free a thread_info from the context of the task that has
144 * been scheduled next, so the original task is already dead.
145 * Calling deactivate here just frees up the data structures.
146 * If the task we're freeing held the last reference to a
147 * hardwall fd, it would have been released prior to this point
148 * anyway via exit_files(), and "hardwall" would be NULL by now.
149 */
150 if (info->task->thread.hardwall)
151 hardwall_deactivate(info->task);
152 #endif
153
154 if (step_state) {
155
156 /*
157 * FIXME: we don't munmap step_state->buffer
158 * because the mm_struct for this process (info->task->mm)
159 * has already been zeroed in exit_mm(). Keeping a
160 * reference to it here seems like a bad move, so this
161 * means we can't munmap() the buffer, and therefore if we
162 * ptrace multiple threads in a process, we will slowly
163 * leak user memory. (Note that as soon as the last
164 * thread in a process dies, we will reclaim all user
165 * memory including single-step buffers in the usual way.)
166 * We should either assign a kernel VA to this buffer
167 * somehow, or we should associate the buffer(s) with the
168 * mm itself so we can clean them up that way.
169 */
170 kfree(step_state);
171 }
172
173 free_pages((unsigned long)info, THREAD_SIZE_ORDER);
174 }
175
176 static void save_arch_state(struct thread_struct *t);
177
copy_thread(unsigned long clone_flags,unsigned long sp,unsigned long stack_size,struct task_struct * p,struct pt_regs * regs)178 int copy_thread(unsigned long clone_flags, unsigned long sp,
179 unsigned long stack_size,
180 struct task_struct *p, struct pt_regs *regs)
181 {
182 struct pt_regs *childregs;
183 unsigned long ksp;
184
185 /*
186 * When creating a new kernel thread we pass sp as zero.
187 * Assign it to a reasonable value now that we have the stack.
188 */
189 if (sp == 0 && regs->ex1 == PL_ICS_EX1(KERNEL_PL, 0))
190 sp = KSTK_TOP(p);
191
192 /*
193 * Do not clone step state from the parent; each thread
194 * must make its own lazily.
195 */
196 task_thread_info(p)->step_state = NULL;
197
198 /*
199 * Start new thread in ret_from_fork so it schedules properly
200 * and then return from interrupt like the parent.
201 */
202 p->thread.pc = (unsigned long) ret_from_fork;
203
204 /* Save user stack top pointer so we can ID the stack vm area later. */
205 p->thread.usp0 = sp;
206
207 /* Record the pid of the process that created this one. */
208 p->thread.creator_pid = current->pid;
209
210 /*
211 * Copy the registers onto the kernel stack so the
212 * return-from-interrupt code will reload it into registers.
213 */
214 childregs = task_pt_regs(p);
215 *childregs = *regs;
216 childregs->regs[0] = 0; /* return value is zero */
217 childregs->sp = sp; /* override with new user stack pointer */
218
219 /*
220 * If CLONE_SETTLS is set, set "tp" in the new task to "r4",
221 * which is passed in as arg #5 to sys_clone().
222 */
223 if (clone_flags & CLONE_SETTLS)
224 childregs->tp = regs->regs[4];
225
226 /*
227 * Copy the callee-saved registers from the passed pt_regs struct
228 * into the context-switch callee-saved registers area.
229 * This way when we start the interrupt-return sequence, the
230 * callee-save registers will be correctly in registers, which
231 * is how we assume the compiler leaves them as we start doing
232 * the normal return-from-interrupt path after calling C code.
233 * Zero out the C ABI save area to mark the top of the stack.
234 */
235 ksp = (unsigned long) childregs;
236 ksp -= C_ABI_SAVE_AREA_SIZE; /* interrupt-entry save area */
237 ((long *)ksp)[0] = ((long *)ksp)[1] = 0;
238 ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long);
239 memcpy((void *)ksp, ®s->regs[CALLEE_SAVED_FIRST_REG],
240 CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long));
241 ksp -= C_ABI_SAVE_AREA_SIZE; /* __switch_to() save area */
242 ((long *)ksp)[0] = ((long *)ksp)[1] = 0;
243 p->thread.ksp = ksp;
244
245 #if CHIP_HAS_TILE_DMA()
246 /*
247 * No DMA in the new thread. We model this on the fact that
248 * fork() clears the pending signals, alarms, and aio for the child.
249 */
250 memset(&p->thread.tile_dma_state, 0, sizeof(struct tile_dma_state));
251 memset(&p->thread.dma_async_tlb, 0, sizeof(struct async_tlb));
252 #endif
253
254 #if CHIP_HAS_SN_PROC()
255 /* Likewise, the new thread is not running static processor code. */
256 p->thread.sn_proc_running = 0;
257 memset(&p->thread.sn_async_tlb, 0, sizeof(struct async_tlb));
258 #endif
259
260 #if CHIP_HAS_PROC_STATUS_SPR()
261 /* New thread has its miscellaneous processor state bits clear. */
262 p->thread.proc_status = 0;
263 #endif
264
265 #ifdef CONFIG_HARDWALL
266 /* New thread does not own any networks. */
267 p->thread.hardwall = NULL;
268 #endif
269
270
271 /*
272 * Start the new thread with the current architecture state
273 * (user interrupt masks, etc.).
274 */
275 save_arch_state(&p->thread);
276
277 return 0;
278 }
279
280 /*
281 * Return "current" if it looks plausible, or else a pointer to a dummy.
282 * This can be helpful if we are just trying to emit a clean panic.
283 */
validate_current(void)284 struct task_struct *validate_current(void)
285 {
286 static struct task_struct corrupt = { .comm = "<corrupt>" };
287 struct task_struct *tsk = current;
288 if (unlikely((unsigned long)tsk < PAGE_OFFSET ||
289 (high_memory && (void *)tsk > high_memory) ||
290 ((unsigned long)tsk & (__alignof__(*tsk) - 1)) != 0)) {
291 pr_err("Corrupt 'current' %p (sp %#lx)\n", tsk, stack_pointer);
292 tsk = &corrupt;
293 }
294 return tsk;
295 }
296
297 /* Take and return the pointer to the previous task, for schedule_tail(). */
sim_notify_fork(struct task_struct * prev)298 struct task_struct *sim_notify_fork(struct task_struct *prev)
299 {
300 struct task_struct *tsk = current;
301 __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK_PARENT |
302 (tsk->thread.creator_pid << _SIM_CONTROL_OPERATOR_BITS));
303 __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK |
304 (tsk->pid << _SIM_CONTROL_OPERATOR_BITS));
305 return prev;
306 }
307
dump_task_regs(struct task_struct * tsk,elf_gregset_t * regs)308 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
309 {
310 struct pt_regs *ptregs = task_pt_regs(tsk);
311 elf_core_copy_regs(regs, ptregs);
312 return 1;
313 }
314
315 #if CHIP_HAS_TILE_DMA()
316
317 /* Allow user processes to access the DMA SPRs */
grant_dma_mpls(void)318 void grant_dma_mpls(void)
319 {
320 #if CONFIG_KERNEL_PL == 2
321 __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
322 __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
323 #else
324 __insn_mtspr(SPR_MPL_DMA_CPL_SET_0, 1);
325 __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_0, 1);
326 #endif
327 }
328
329 /* Forbid user processes from accessing the DMA SPRs */
restrict_dma_mpls(void)330 void restrict_dma_mpls(void)
331 {
332 #if CONFIG_KERNEL_PL == 2
333 __insn_mtspr(SPR_MPL_DMA_CPL_SET_2, 1);
334 __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_2, 1);
335 #else
336 __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
337 __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
338 #endif
339 }
340
341 /* Pause the DMA engine, then save off its state registers. */
save_tile_dma_state(struct tile_dma_state * dma)342 static void save_tile_dma_state(struct tile_dma_state *dma)
343 {
344 unsigned long state = __insn_mfspr(SPR_DMA_USER_STATUS);
345 unsigned long post_suspend_state;
346
347 /* If we're running, suspend the engine. */
348 if ((state & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK)
349 __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK);
350
351 /*
352 * Wait for the engine to idle, then save regs. Note that we
353 * want to record the "running" bit from before suspension,
354 * and the "done" bit from after, so that we can properly
355 * distinguish a case where the user suspended the engine from
356 * the case where the kernel suspended as part of the context
357 * swap.
358 */
359 do {
360 post_suspend_state = __insn_mfspr(SPR_DMA_USER_STATUS);
361 } while (post_suspend_state & SPR_DMA_STATUS__BUSY_MASK);
362
363 dma->src = __insn_mfspr(SPR_DMA_SRC_ADDR);
364 dma->src_chunk = __insn_mfspr(SPR_DMA_SRC_CHUNK_ADDR);
365 dma->dest = __insn_mfspr(SPR_DMA_DST_ADDR);
366 dma->dest_chunk = __insn_mfspr(SPR_DMA_DST_CHUNK_ADDR);
367 dma->strides = __insn_mfspr(SPR_DMA_STRIDE);
368 dma->chunk_size = __insn_mfspr(SPR_DMA_CHUNK_SIZE);
369 dma->byte = __insn_mfspr(SPR_DMA_BYTE);
370 dma->status = (state & SPR_DMA_STATUS__RUNNING_MASK) |
371 (post_suspend_state & SPR_DMA_STATUS__DONE_MASK);
372 }
373
374 /* Restart a DMA that was running before we were context-switched out. */
restore_tile_dma_state(struct thread_struct * t)375 static void restore_tile_dma_state(struct thread_struct *t)
376 {
377 const struct tile_dma_state *dma = &t->tile_dma_state;
378
379 /*
380 * The only way to restore the done bit is to run a zero
381 * length transaction.
382 */
383 if ((dma->status & SPR_DMA_STATUS__DONE_MASK) &&
384 !(__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__DONE_MASK)) {
385 __insn_mtspr(SPR_DMA_BYTE, 0);
386 __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
387 while (__insn_mfspr(SPR_DMA_USER_STATUS) &
388 SPR_DMA_STATUS__BUSY_MASK)
389 ;
390 }
391
392 __insn_mtspr(SPR_DMA_SRC_ADDR, dma->src);
393 __insn_mtspr(SPR_DMA_SRC_CHUNK_ADDR, dma->src_chunk);
394 __insn_mtspr(SPR_DMA_DST_ADDR, dma->dest);
395 __insn_mtspr(SPR_DMA_DST_CHUNK_ADDR, dma->dest_chunk);
396 __insn_mtspr(SPR_DMA_STRIDE, dma->strides);
397 __insn_mtspr(SPR_DMA_CHUNK_SIZE, dma->chunk_size);
398 __insn_mtspr(SPR_DMA_BYTE, dma->byte);
399
400 /*
401 * Restart the engine if we were running and not done.
402 * Clear a pending async DMA fault that we were waiting on return
403 * to user space to execute, since we expect the DMA engine
404 * to regenerate those faults for us now. Note that we don't
405 * try to clear the TIF_ASYNC_TLB flag, since it's relatively
406 * harmless if set, and it covers both DMA and the SN processor.
407 */
408 if ((dma->status & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) {
409 t->dma_async_tlb.fault_num = 0;
410 __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
411 }
412 }
413
414 #endif
415
save_arch_state(struct thread_struct * t)416 static void save_arch_state(struct thread_struct *t)
417 {
418 #if CHIP_HAS_SPLIT_INTR_MASK()
419 t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0_0) |
420 ((u64)__insn_mfspr(SPR_INTERRUPT_MASK_0_1) << 32);
421 #else
422 t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0);
423 #endif
424 t->ex_context[0] = __insn_mfspr(SPR_EX_CONTEXT_0_0);
425 t->ex_context[1] = __insn_mfspr(SPR_EX_CONTEXT_0_1);
426 t->system_save[0] = __insn_mfspr(SPR_SYSTEM_SAVE_0_0);
427 t->system_save[1] = __insn_mfspr(SPR_SYSTEM_SAVE_0_1);
428 t->system_save[2] = __insn_mfspr(SPR_SYSTEM_SAVE_0_2);
429 t->system_save[3] = __insn_mfspr(SPR_SYSTEM_SAVE_0_3);
430 t->intctrl_0 = __insn_mfspr(SPR_INTCTRL_0_STATUS);
431 #if CHIP_HAS_PROC_STATUS_SPR()
432 t->proc_status = __insn_mfspr(SPR_PROC_STATUS);
433 #endif
434 #if !CHIP_HAS_FIXED_INTVEC_BASE()
435 t->interrupt_vector_base = __insn_mfspr(SPR_INTERRUPT_VECTOR_BASE_0);
436 #endif
437 #if CHIP_HAS_TILE_RTF_HWM()
438 t->tile_rtf_hwm = __insn_mfspr(SPR_TILE_RTF_HWM);
439 #endif
440 #if CHIP_HAS_DSTREAM_PF()
441 t->dstream_pf = __insn_mfspr(SPR_DSTREAM_PF);
442 #endif
443 }
444
restore_arch_state(const struct thread_struct * t)445 static void restore_arch_state(const struct thread_struct *t)
446 {
447 #if CHIP_HAS_SPLIT_INTR_MASK()
448 __insn_mtspr(SPR_INTERRUPT_MASK_0_0, (u32) t->interrupt_mask);
449 __insn_mtspr(SPR_INTERRUPT_MASK_0_1, t->interrupt_mask >> 32);
450 #else
451 __insn_mtspr(SPR_INTERRUPT_MASK_0, t->interrupt_mask);
452 #endif
453 __insn_mtspr(SPR_EX_CONTEXT_0_0, t->ex_context[0]);
454 __insn_mtspr(SPR_EX_CONTEXT_0_1, t->ex_context[1]);
455 __insn_mtspr(SPR_SYSTEM_SAVE_0_0, t->system_save[0]);
456 __insn_mtspr(SPR_SYSTEM_SAVE_0_1, t->system_save[1]);
457 __insn_mtspr(SPR_SYSTEM_SAVE_0_2, t->system_save[2]);
458 __insn_mtspr(SPR_SYSTEM_SAVE_0_3, t->system_save[3]);
459 __insn_mtspr(SPR_INTCTRL_0_STATUS, t->intctrl_0);
460 #if CHIP_HAS_PROC_STATUS_SPR()
461 __insn_mtspr(SPR_PROC_STATUS, t->proc_status);
462 #endif
463 #if !CHIP_HAS_FIXED_INTVEC_BASE()
464 __insn_mtspr(SPR_INTERRUPT_VECTOR_BASE_0, t->interrupt_vector_base);
465 #endif
466 #if CHIP_HAS_TILE_RTF_HWM()
467 __insn_mtspr(SPR_TILE_RTF_HWM, t->tile_rtf_hwm);
468 #endif
469 #if CHIP_HAS_DSTREAM_PF()
470 __insn_mtspr(SPR_DSTREAM_PF, t->dstream_pf);
471 #endif
472 }
473
474
_prepare_arch_switch(struct task_struct * next)475 void _prepare_arch_switch(struct task_struct *next)
476 {
477 #if CHIP_HAS_SN_PROC()
478 int snctl;
479 #endif
480 #if CHIP_HAS_TILE_DMA()
481 struct tile_dma_state *dma = ¤t->thread.tile_dma_state;
482 if (dma->enabled)
483 save_tile_dma_state(dma);
484 #endif
485 #if CHIP_HAS_SN_PROC()
486 /*
487 * Suspend the static network processor if it was running.
488 * We do not suspend the fabric itself, just like we don't
489 * try to suspend the UDN.
490 */
491 snctl = __insn_mfspr(SPR_SNCTL);
492 current->thread.sn_proc_running =
493 (snctl & SPR_SNCTL__FRZPROC_MASK) == 0;
494 if (current->thread.sn_proc_running)
495 __insn_mtspr(SPR_SNCTL, snctl | SPR_SNCTL__FRZPROC_MASK);
496 #endif
497 }
498
499
_switch_to(struct task_struct * prev,struct task_struct * next)500 struct task_struct *__sched _switch_to(struct task_struct *prev,
501 struct task_struct *next)
502 {
503 /* DMA state is already saved; save off other arch state. */
504 save_arch_state(&prev->thread);
505
506 #if CHIP_HAS_TILE_DMA()
507 /*
508 * Restore DMA in new task if desired.
509 * Note that it is only safe to restart here since interrupts
510 * are disabled, so we can't take any DMATLB miss or access
511 * interrupts before we have finished switching stacks.
512 */
513 if (next->thread.tile_dma_state.enabled) {
514 restore_tile_dma_state(&next->thread);
515 grant_dma_mpls();
516 } else {
517 restrict_dma_mpls();
518 }
519 #endif
520
521 /* Restore other arch state. */
522 restore_arch_state(&next->thread);
523
524 #if CHIP_HAS_SN_PROC()
525 /*
526 * Restart static network processor in the new process
527 * if it was running before.
528 */
529 if (next->thread.sn_proc_running) {
530 int snctl = __insn_mfspr(SPR_SNCTL);
531 __insn_mtspr(SPR_SNCTL, snctl & ~SPR_SNCTL__FRZPROC_MASK);
532 }
533 #endif
534
535 #ifdef CONFIG_HARDWALL
536 /* Enable or disable access to the network registers appropriately. */
537 if (prev->thread.hardwall != NULL) {
538 if (next->thread.hardwall == NULL)
539 restrict_network_mpls();
540 } else if (next->thread.hardwall != NULL) {
541 grant_network_mpls();
542 }
543 #endif
544
545 /*
546 * Switch kernel SP, PC, and callee-saved registers.
547 * In the context of the new task, return the old task pointer
548 * (i.e. the task that actually called __switch_to).
549 * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp.
550 */
551 return __switch_to(prev, next, next_current_ksp0(next));
552 }
553
554 /*
555 * This routine is called on return from interrupt if any of the
556 * TIF_WORK_MASK flags are set in thread_info->flags. It is
557 * entered with interrupts disabled so we don't miss an event
558 * that modified the thread_info flags. If any flag is set, we
559 * handle it and return, and the calling assembly code will
560 * re-disable interrupts, reload the thread flags, and call back
561 * if more flags need to be handled.
562 *
563 * We return whether we need to check the thread_info flags again
564 * or not. Note that we don't clear TIF_SINGLESTEP here, so it's
565 * important that it be tested last, and then claim that we don't
566 * need to recheck the flags.
567 */
do_work_pending(struct pt_regs * regs,u32 thread_info_flags)568 int do_work_pending(struct pt_regs *regs, u32 thread_info_flags)
569 {
570 /* If we enter in kernel mode, do nothing and exit the caller loop. */
571 if (!user_mode(regs))
572 return 0;
573
574 if (thread_info_flags & _TIF_NEED_RESCHED) {
575 schedule();
576 return 1;
577 }
578 #if CHIP_HAS_TILE_DMA() || CHIP_HAS_SN_PROC()
579 if (thread_info_flags & _TIF_ASYNC_TLB) {
580 do_async_page_fault(regs);
581 return 1;
582 }
583 #endif
584 if (thread_info_flags & _TIF_SIGPENDING) {
585 do_signal(regs);
586 return 1;
587 }
588 if (thread_info_flags & _TIF_NOTIFY_RESUME) {
589 clear_thread_flag(TIF_NOTIFY_RESUME);
590 tracehook_notify_resume(regs);
591 if (current->replacement_session_keyring)
592 key_replace_session_keyring();
593 return 1;
594 }
595 if (thread_info_flags & _TIF_SINGLESTEP) {
596 single_step_once(regs);
597 return 0;
598 }
599 panic("work_pending: bad flags %#x\n", thread_info_flags);
600 }
601
602 /* Note there is an implicit fifth argument if (clone_flags & CLONE_SETTLS). */
SYSCALL_DEFINE5(clone,unsigned long,clone_flags,unsigned long,newsp,void __user *,parent_tidptr,void __user *,child_tidptr,struct pt_regs *,regs)603 SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
604 void __user *, parent_tidptr, void __user *, child_tidptr,
605 struct pt_regs *, regs)
606 {
607 if (!newsp)
608 newsp = regs->sp;
609 return do_fork(clone_flags, newsp, regs, 0,
610 parent_tidptr, child_tidptr);
611 }
612
613 /*
614 * sys_execve() executes a new program.
615 */
SYSCALL_DEFINE4(execve,const char __user *,path,const char __user * const __user *,argv,const char __user * const __user *,envp,struct pt_regs *,regs)616 SYSCALL_DEFINE4(execve, const char __user *, path,
617 const char __user *const __user *, argv,
618 const char __user *const __user *, envp,
619 struct pt_regs *, regs)
620 {
621 long error;
622 char *filename;
623
624 filename = getname(path);
625 error = PTR_ERR(filename);
626 if (IS_ERR(filename))
627 goto out;
628 error = do_execve(filename, argv, envp, regs);
629 putname(filename);
630 if (error == 0)
631 single_step_execve();
632 out:
633 return error;
634 }
635
636 #ifdef CONFIG_COMPAT
compat_sys_execve(const char __user * path,compat_uptr_t __user * argv,compat_uptr_t __user * envp,struct pt_regs * regs)637 long compat_sys_execve(const char __user *path,
638 compat_uptr_t __user *argv,
639 compat_uptr_t __user *envp,
640 struct pt_regs *regs)
641 {
642 long error;
643 char *filename;
644
645 filename = getname(path);
646 error = PTR_ERR(filename);
647 if (IS_ERR(filename))
648 goto out;
649 error = compat_do_execve(filename, argv, envp, regs);
650 putname(filename);
651 if (error == 0)
652 single_step_execve();
653 out:
654 return error;
655 }
656 #endif
657
get_wchan(struct task_struct * p)658 unsigned long get_wchan(struct task_struct *p)
659 {
660 struct KBacktraceIterator kbt;
661
662 if (!p || p == current || p->state == TASK_RUNNING)
663 return 0;
664
665 for (KBacktraceIterator_init(&kbt, p, NULL);
666 !KBacktraceIterator_end(&kbt);
667 KBacktraceIterator_next(&kbt)) {
668 if (!in_sched_functions(kbt.it.pc))
669 return kbt.it.pc;
670 }
671
672 return 0;
673 }
674
675 /*
676 * We pass in lr as zero (cleared in kernel_thread) and the caller
677 * part of the backtrace ABI on the stack also zeroed (in copy_thread)
678 * so that backtraces will stop with this function.
679 * Note that we don't use r0, since copy_thread() clears it.
680 */
start_kernel_thread(int dummy,int (* fn)(int),int arg)681 static void start_kernel_thread(int dummy, int (*fn)(int), int arg)
682 {
683 do_exit(fn(arg));
684 }
685
686 /*
687 * Create a kernel thread
688 */
kernel_thread(int (* fn)(void *),void * arg,unsigned long flags)689 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
690 {
691 struct pt_regs regs;
692
693 memset(®s, 0, sizeof(regs));
694 regs.ex1 = PL_ICS_EX1(KERNEL_PL, 0); /* run at kernel PL, no ICS */
695 regs.pc = (long) start_kernel_thread;
696 regs.flags = PT_FLAGS_CALLER_SAVES; /* need to restore r1 and r2 */
697 regs.regs[1] = (long) fn; /* function pointer */
698 regs.regs[2] = (long) arg; /* parameter register */
699
700 /* Ok, create the new process.. */
701 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s,
702 0, NULL, NULL);
703 }
704 EXPORT_SYMBOL(kernel_thread);
705
706 /* Flush thread state. */
flush_thread(void)707 void flush_thread(void)
708 {
709 /* Nothing */
710 }
711
712 /*
713 * Free current thread data structures etc..
714 */
exit_thread(void)715 void exit_thread(void)
716 {
717 /* Nothing */
718 }
719
show_regs(struct pt_regs * regs)720 void show_regs(struct pt_regs *regs)
721 {
722 struct task_struct *tsk = validate_current();
723 int i;
724
725 pr_err("\n");
726 pr_err(" Pid: %d, comm: %20s, CPU: %d\n",
727 tsk->pid, tsk->comm, smp_processor_id());
728 #ifdef __tilegx__
729 for (i = 0; i < 51; i += 3)
730 pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
731 i, regs->regs[i], i+1, regs->regs[i+1],
732 i+2, regs->regs[i+2]);
733 pr_err(" r51: "REGFMT" r52: "REGFMT" tp : "REGFMT"\n",
734 regs->regs[51], regs->regs[52], regs->tp);
735 pr_err(" sp : "REGFMT" lr : "REGFMT"\n", regs->sp, regs->lr);
736 #else
737 for (i = 0; i < 52; i += 4)
738 pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT
739 " r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
740 i, regs->regs[i], i+1, regs->regs[i+1],
741 i+2, regs->regs[i+2], i+3, regs->regs[i+3]);
742 pr_err(" r52: "REGFMT" tp : "REGFMT" sp : "REGFMT" lr : "REGFMT"\n",
743 regs->regs[52], regs->tp, regs->sp, regs->lr);
744 #endif
745 pr_err(" pc : "REGFMT" ex1: %ld faultnum: %ld\n",
746 regs->pc, regs->ex1, regs->faultnum);
747
748 dump_stack_regs(regs);
749 }
750