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 <asm/system.h>
29 #include <asm/stack.h>
30 #include <asm/homecache.h>
31 #include <asm/syscalls.h>
32 #ifdef CONFIG_HARDWALL
33 #include <asm/hardwall.h>
34 #endif
35 #include <arch/chip.h>
36 #include <arch/abi.h>
37
38
39 /*
40 * Use the (x86) "idle=poll" option to prefer low latency when leaving the
41 * idle loop over low power while in the idle loop, e.g. if we have
42 * one thread per core and we want to get threads out of futex waits fast.
43 */
44 static int no_idle_nap;
idle_setup(char * str)45 static int __init idle_setup(char *str)
46 {
47 if (!str)
48 return -EINVAL;
49
50 if (!strcmp(str, "poll")) {
51 pr_info("using polling idle threads.\n");
52 no_idle_nap = 1;
53 } else if (!strcmp(str, "halt"))
54 no_idle_nap = 0;
55 else
56 return -1;
57
58 return 0;
59 }
60 early_param("idle", idle_setup);
61
62 /*
63 * The idle thread. There's no useful work to be
64 * done, so just try to conserve power and have a
65 * low exit latency (ie sit in a loop waiting for
66 * somebody to say that they'd like to reschedule)
67 */
cpu_idle(void)68 void cpu_idle(void)
69 {
70 int cpu = smp_processor_id();
71
72
73 current_thread_info()->status |= TS_POLLING;
74
75 if (no_idle_nap) {
76 while (1) {
77 while (!need_resched())
78 cpu_relax();
79 schedule();
80 }
81 }
82
83 /* endless idle loop with no priority at all */
84 while (1) {
85 tick_nohz_stop_sched_tick(1);
86 while (!need_resched()) {
87 if (cpu_is_offline(cpu))
88 BUG(); /* no HOTPLUG_CPU */
89
90 local_irq_disable();
91 __get_cpu_var(irq_stat).idle_timestamp = jiffies;
92 current_thread_info()->status &= ~TS_POLLING;
93 /*
94 * TS_POLLING-cleared state must be visible before we
95 * test NEED_RESCHED:
96 */
97 smp_mb();
98
99 if (!need_resched())
100 _cpu_idle();
101 else
102 local_irq_enable();
103 current_thread_info()->status |= TS_POLLING;
104 }
105 tick_nohz_restart_sched_tick();
106 preempt_enable_no_resched();
107 schedule();
108 preempt_disable();
109 }
110 }
111
alloc_thread_info_node(struct task_struct * task,int node)112 struct thread_info *alloc_thread_info_node(struct task_struct *task, int node)
113 {
114 struct page *page;
115 gfp_t flags = GFP_KERNEL;
116
117 #ifdef CONFIG_DEBUG_STACK_USAGE
118 flags |= __GFP_ZERO;
119 #endif
120
121 page = alloc_pages_node(node, flags, THREAD_SIZE_ORDER);
122 if (!page)
123 return NULL;
124
125 return (struct thread_info *)page_address(page);
126 }
127
128 /*
129 * Free a thread_info node, and all of its derivative
130 * data structures.
131 */
free_thread_info(struct thread_info * info)132 void free_thread_info(struct thread_info *info)
133 {
134 struct single_step_state *step_state = info->step_state;
135
136 #ifdef CONFIG_HARDWALL
137 /*
138 * We free a thread_info from the context of the task that has
139 * been scheduled next, so the original task is already dead.
140 * Calling deactivate here just frees up the data structures.
141 * If the task we're freeing held the last reference to a
142 * hardwall fd, it would have been released prior to this point
143 * anyway via exit_files(), and "hardwall" would be NULL by now.
144 */
145 if (info->task->thread.hardwall)
146 hardwall_deactivate(info->task);
147 #endif
148
149 if (step_state) {
150
151 /*
152 * FIXME: we don't munmap step_state->buffer
153 * because the mm_struct for this process (info->task->mm)
154 * has already been zeroed in exit_mm(). Keeping a
155 * reference to it here seems like a bad move, so this
156 * means we can't munmap() the buffer, and therefore if we
157 * ptrace multiple threads in a process, we will slowly
158 * leak user memory. (Note that as soon as the last
159 * thread in a process dies, we will reclaim all user
160 * memory including single-step buffers in the usual way.)
161 * We should either assign a kernel VA to this buffer
162 * somehow, or we should associate the buffer(s) with the
163 * mm itself so we can clean them up that way.
164 */
165 kfree(step_state);
166 }
167
168 free_pages((unsigned long)info, THREAD_SIZE_ORDER);
169 }
170
171 static void save_arch_state(struct thread_struct *t);
172
copy_thread(unsigned long clone_flags,unsigned long sp,unsigned long stack_size,struct task_struct * p,struct pt_regs * regs)173 int copy_thread(unsigned long clone_flags, unsigned long sp,
174 unsigned long stack_size,
175 struct task_struct *p, struct pt_regs *regs)
176 {
177 struct pt_regs *childregs;
178 unsigned long ksp;
179
180 /*
181 * When creating a new kernel thread we pass sp as zero.
182 * Assign it to a reasonable value now that we have the stack.
183 */
184 if (sp == 0 && regs->ex1 == PL_ICS_EX1(KERNEL_PL, 0))
185 sp = KSTK_TOP(p);
186
187 /*
188 * Do not clone step state from the parent; each thread
189 * must make its own lazily.
190 */
191 task_thread_info(p)->step_state = NULL;
192
193 /*
194 * Start new thread in ret_from_fork so it schedules properly
195 * and then return from interrupt like the parent.
196 */
197 p->thread.pc = (unsigned long) ret_from_fork;
198
199 /* Save user stack top pointer so we can ID the stack vm area later. */
200 p->thread.usp0 = sp;
201
202 /* Record the pid of the process that created this one. */
203 p->thread.creator_pid = current->pid;
204
205 /*
206 * Copy the registers onto the kernel stack so the
207 * return-from-interrupt code will reload it into registers.
208 */
209 childregs = task_pt_regs(p);
210 *childregs = *regs;
211 childregs->regs[0] = 0; /* return value is zero */
212 childregs->sp = sp; /* override with new user stack pointer */
213
214 /*
215 * If CLONE_SETTLS is set, set "tp" in the new task to "r4",
216 * which is passed in as arg #5 to sys_clone().
217 */
218 if (clone_flags & CLONE_SETTLS)
219 childregs->tp = regs->regs[4];
220
221 /*
222 * Copy the callee-saved registers from the passed pt_regs struct
223 * into the context-switch callee-saved registers area.
224 * This way when we start the interrupt-return sequence, the
225 * callee-save registers will be correctly in registers, which
226 * is how we assume the compiler leaves them as we start doing
227 * the normal return-from-interrupt path after calling C code.
228 * Zero out the C ABI save area to mark the top of the stack.
229 */
230 ksp = (unsigned long) childregs;
231 ksp -= C_ABI_SAVE_AREA_SIZE; /* interrupt-entry save area */
232 ((long *)ksp)[0] = ((long *)ksp)[1] = 0;
233 ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long);
234 memcpy((void *)ksp, ®s->regs[CALLEE_SAVED_FIRST_REG],
235 CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long));
236 ksp -= C_ABI_SAVE_AREA_SIZE; /* __switch_to() save area */
237 ((long *)ksp)[0] = ((long *)ksp)[1] = 0;
238 p->thread.ksp = ksp;
239
240 #if CHIP_HAS_TILE_DMA()
241 /*
242 * No DMA in the new thread. We model this on the fact that
243 * fork() clears the pending signals, alarms, and aio for the child.
244 */
245 memset(&p->thread.tile_dma_state, 0, sizeof(struct tile_dma_state));
246 memset(&p->thread.dma_async_tlb, 0, sizeof(struct async_tlb));
247 #endif
248
249 #if CHIP_HAS_SN_PROC()
250 /* Likewise, the new thread is not running static processor code. */
251 p->thread.sn_proc_running = 0;
252 memset(&p->thread.sn_async_tlb, 0, sizeof(struct async_tlb));
253 #endif
254
255 #if CHIP_HAS_PROC_STATUS_SPR()
256 /* New thread has its miscellaneous processor state bits clear. */
257 p->thread.proc_status = 0;
258 #endif
259
260 #ifdef CONFIG_HARDWALL
261 /* New thread does not own any networks. */
262 p->thread.hardwall = NULL;
263 #endif
264
265
266 /*
267 * Start the new thread with the current architecture state
268 * (user interrupt masks, etc.).
269 */
270 save_arch_state(&p->thread);
271
272 return 0;
273 }
274
275 /*
276 * Return "current" if it looks plausible, or else a pointer to a dummy.
277 * This can be helpful if we are just trying to emit a clean panic.
278 */
validate_current(void)279 struct task_struct *validate_current(void)
280 {
281 static struct task_struct corrupt = { .comm = "<corrupt>" };
282 struct task_struct *tsk = current;
283 if (unlikely((unsigned long)tsk < PAGE_OFFSET ||
284 (void *)tsk > high_memory ||
285 ((unsigned long)tsk & (__alignof__(*tsk) - 1)) != 0)) {
286 pr_err("Corrupt 'current' %p (sp %#lx)\n", tsk, stack_pointer);
287 tsk = &corrupt;
288 }
289 return tsk;
290 }
291
292 /* Take and return the pointer to the previous task, for schedule_tail(). */
sim_notify_fork(struct task_struct * prev)293 struct task_struct *sim_notify_fork(struct task_struct *prev)
294 {
295 struct task_struct *tsk = current;
296 __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK_PARENT |
297 (tsk->thread.creator_pid << _SIM_CONTROL_OPERATOR_BITS));
298 __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK |
299 (tsk->pid << _SIM_CONTROL_OPERATOR_BITS));
300 return prev;
301 }
302
dump_task_regs(struct task_struct * tsk,elf_gregset_t * regs)303 int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs)
304 {
305 struct pt_regs *ptregs = task_pt_regs(tsk);
306 elf_core_copy_regs(regs, ptregs);
307 return 1;
308 }
309
310 #if CHIP_HAS_TILE_DMA()
311
312 /* Allow user processes to access the DMA SPRs */
grant_dma_mpls(void)313 void grant_dma_mpls(void)
314 {
315 #if CONFIG_KERNEL_PL == 2
316 __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
317 __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
318 #else
319 __insn_mtspr(SPR_MPL_DMA_CPL_SET_0, 1);
320 __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_0, 1);
321 #endif
322 }
323
324 /* Forbid user processes from accessing the DMA SPRs */
restrict_dma_mpls(void)325 void restrict_dma_mpls(void)
326 {
327 #if CONFIG_KERNEL_PL == 2
328 __insn_mtspr(SPR_MPL_DMA_CPL_SET_2, 1);
329 __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_2, 1);
330 #else
331 __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1);
332 __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1);
333 #endif
334 }
335
336 /* Pause the DMA engine, then save off its state registers. */
save_tile_dma_state(struct tile_dma_state * dma)337 static void save_tile_dma_state(struct tile_dma_state *dma)
338 {
339 unsigned long state = __insn_mfspr(SPR_DMA_USER_STATUS);
340 unsigned long post_suspend_state;
341
342 /* If we're running, suspend the engine. */
343 if ((state & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK)
344 __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK);
345
346 /*
347 * Wait for the engine to idle, then save regs. Note that we
348 * want to record the "running" bit from before suspension,
349 * and the "done" bit from after, so that we can properly
350 * distinguish a case where the user suspended the engine from
351 * the case where the kernel suspended as part of the context
352 * swap.
353 */
354 do {
355 post_suspend_state = __insn_mfspr(SPR_DMA_USER_STATUS);
356 } while (post_suspend_state & SPR_DMA_STATUS__BUSY_MASK);
357
358 dma->src = __insn_mfspr(SPR_DMA_SRC_ADDR);
359 dma->src_chunk = __insn_mfspr(SPR_DMA_SRC_CHUNK_ADDR);
360 dma->dest = __insn_mfspr(SPR_DMA_DST_ADDR);
361 dma->dest_chunk = __insn_mfspr(SPR_DMA_DST_CHUNK_ADDR);
362 dma->strides = __insn_mfspr(SPR_DMA_STRIDE);
363 dma->chunk_size = __insn_mfspr(SPR_DMA_CHUNK_SIZE);
364 dma->byte = __insn_mfspr(SPR_DMA_BYTE);
365 dma->status = (state & SPR_DMA_STATUS__RUNNING_MASK) |
366 (post_suspend_state & SPR_DMA_STATUS__DONE_MASK);
367 }
368
369 /* Restart a DMA that was running before we were context-switched out. */
restore_tile_dma_state(struct thread_struct * t)370 static void restore_tile_dma_state(struct thread_struct *t)
371 {
372 const struct tile_dma_state *dma = &t->tile_dma_state;
373
374 /*
375 * The only way to restore the done bit is to run a zero
376 * length transaction.
377 */
378 if ((dma->status & SPR_DMA_STATUS__DONE_MASK) &&
379 !(__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__DONE_MASK)) {
380 __insn_mtspr(SPR_DMA_BYTE, 0);
381 __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
382 while (__insn_mfspr(SPR_DMA_USER_STATUS) &
383 SPR_DMA_STATUS__BUSY_MASK)
384 ;
385 }
386
387 __insn_mtspr(SPR_DMA_SRC_ADDR, dma->src);
388 __insn_mtspr(SPR_DMA_SRC_CHUNK_ADDR, dma->src_chunk);
389 __insn_mtspr(SPR_DMA_DST_ADDR, dma->dest);
390 __insn_mtspr(SPR_DMA_DST_CHUNK_ADDR, dma->dest_chunk);
391 __insn_mtspr(SPR_DMA_STRIDE, dma->strides);
392 __insn_mtspr(SPR_DMA_CHUNK_SIZE, dma->chunk_size);
393 __insn_mtspr(SPR_DMA_BYTE, dma->byte);
394
395 /*
396 * Restart the engine if we were running and not done.
397 * Clear a pending async DMA fault that we were waiting on return
398 * to user space to execute, since we expect the DMA engine
399 * to regenerate those faults for us now. Note that we don't
400 * try to clear the TIF_ASYNC_TLB flag, since it's relatively
401 * harmless if set, and it covers both DMA and the SN processor.
402 */
403 if ((dma->status & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) {
404 t->dma_async_tlb.fault_num = 0;
405 __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK);
406 }
407 }
408
409 #endif
410
save_arch_state(struct thread_struct * t)411 static void save_arch_state(struct thread_struct *t)
412 {
413 #if CHIP_HAS_SPLIT_INTR_MASK()
414 t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0_0) |
415 ((u64)__insn_mfspr(SPR_INTERRUPT_MASK_0_1) << 32);
416 #else
417 t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0);
418 #endif
419 t->ex_context[0] = __insn_mfspr(SPR_EX_CONTEXT_0_0);
420 t->ex_context[1] = __insn_mfspr(SPR_EX_CONTEXT_0_1);
421 t->system_save[0] = __insn_mfspr(SPR_SYSTEM_SAVE_0_0);
422 t->system_save[1] = __insn_mfspr(SPR_SYSTEM_SAVE_0_1);
423 t->system_save[2] = __insn_mfspr(SPR_SYSTEM_SAVE_0_2);
424 t->system_save[3] = __insn_mfspr(SPR_SYSTEM_SAVE_0_3);
425 t->intctrl_0 = __insn_mfspr(SPR_INTCTRL_0_STATUS);
426 #if CHIP_HAS_PROC_STATUS_SPR()
427 t->proc_status = __insn_mfspr(SPR_PROC_STATUS);
428 #endif
429 #if !CHIP_HAS_FIXED_INTVEC_BASE()
430 t->interrupt_vector_base = __insn_mfspr(SPR_INTERRUPT_VECTOR_BASE_0);
431 #endif
432 #if CHIP_HAS_TILE_RTF_HWM()
433 t->tile_rtf_hwm = __insn_mfspr(SPR_TILE_RTF_HWM);
434 #endif
435 #if CHIP_HAS_DSTREAM_PF()
436 t->dstream_pf = __insn_mfspr(SPR_DSTREAM_PF);
437 #endif
438 }
439
restore_arch_state(const struct thread_struct * t)440 static void restore_arch_state(const struct thread_struct *t)
441 {
442 #if CHIP_HAS_SPLIT_INTR_MASK()
443 __insn_mtspr(SPR_INTERRUPT_MASK_0_0, (u32) t->interrupt_mask);
444 __insn_mtspr(SPR_INTERRUPT_MASK_0_1, t->interrupt_mask >> 32);
445 #else
446 __insn_mtspr(SPR_INTERRUPT_MASK_0, t->interrupt_mask);
447 #endif
448 __insn_mtspr(SPR_EX_CONTEXT_0_0, t->ex_context[0]);
449 __insn_mtspr(SPR_EX_CONTEXT_0_1, t->ex_context[1]);
450 __insn_mtspr(SPR_SYSTEM_SAVE_0_0, t->system_save[0]);
451 __insn_mtspr(SPR_SYSTEM_SAVE_0_1, t->system_save[1]);
452 __insn_mtspr(SPR_SYSTEM_SAVE_0_2, t->system_save[2]);
453 __insn_mtspr(SPR_SYSTEM_SAVE_0_3, t->system_save[3]);
454 __insn_mtspr(SPR_INTCTRL_0_STATUS, t->intctrl_0);
455 #if CHIP_HAS_PROC_STATUS_SPR()
456 __insn_mtspr(SPR_PROC_STATUS, t->proc_status);
457 #endif
458 #if !CHIP_HAS_FIXED_INTVEC_BASE()
459 __insn_mtspr(SPR_INTERRUPT_VECTOR_BASE_0, t->interrupt_vector_base);
460 #endif
461 #if CHIP_HAS_TILE_RTF_HWM()
462 __insn_mtspr(SPR_TILE_RTF_HWM, t->tile_rtf_hwm);
463 #endif
464 #if CHIP_HAS_DSTREAM_PF()
465 __insn_mtspr(SPR_DSTREAM_PF, t->dstream_pf);
466 #endif
467 }
468
469
_prepare_arch_switch(struct task_struct * next)470 void _prepare_arch_switch(struct task_struct *next)
471 {
472 #if CHIP_HAS_SN_PROC()
473 int snctl;
474 #endif
475 #if CHIP_HAS_TILE_DMA()
476 struct tile_dma_state *dma = ¤t->thread.tile_dma_state;
477 if (dma->enabled)
478 save_tile_dma_state(dma);
479 #endif
480 #if CHIP_HAS_SN_PROC()
481 /*
482 * Suspend the static network processor if it was running.
483 * We do not suspend the fabric itself, just like we don't
484 * try to suspend the UDN.
485 */
486 snctl = __insn_mfspr(SPR_SNCTL);
487 current->thread.sn_proc_running =
488 (snctl & SPR_SNCTL__FRZPROC_MASK) == 0;
489 if (current->thread.sn_proc_running)
490 __insn_mtspr(SPR_SNCTL, snctl | SPR_SNCTL__FRZPROC_MASK);
491 #endif
492 }
493
494
_switch_to(struct task_struct * prev,struct task_struct * next)495 struct task_struct *__sched _switch_to(struct task_struct *prev,
496 struct task_struct *next)
497 {
498 /* DMA state is already saved; save off other arch state. */
499 save_arch_state(&prev->thread);
500
501 #if CHIP_HAS_TILE_DMA()
502 /*
503 * Restore DMA in new task if desired.
504 * Note that it is only safe to restart here since interrupts
505 * are disabled, so we can't take any DMATLB miss or access
506 * interrupts before we have finished switching stacks.
507 */
508 if (next->thread.tile_dma_state.enabled) {
509 restore_tile_dma_state(&next->thread);
510 grant_dma_mpls();
511 } else {
512 restrict_dma_mpls();
513 }
514 #endif
515
516 /* Restore other arch state. */
517 restore_arch_state(&next->thread);
518
519 #if CHIP_HAS_SN_PROC()
520 /*
521 * Restart static network processor in the new process
522 * if it was running before.
523 */
524 if (next->thread.sn_proc_running) {
525 int snctl = __insn_mfspr(SPR_SNCTL);
526 __insn_mtspr(SPR_SNCTL, snctl & ~SPR_SNCTL__FRZPROC_MASK);
527 }
528 #endif
529
530 #ifdef CONFIG_HARDWALL
531 /* Enable or disable access to the network registers appropriately. */
532 if (prev->thread.hardwall != NULL) {
533 if (next->thread.hardwall == NULL)
534 restrict_network_mpls();
535 } else if (next->thread.hardwall != NULL) {
536 grant_network_mpls();
537 }
538 #endif
539
540 /*
541 * Switch kernel SP, PC, and callee-saved registers.
542 * In the context of the new task, return the old task pointer
543 * (i.e. the task that actually called __switch_to).
544 * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp.
545 */
546 return __switch_to(prev, next, next_current_ksp0(next));
547 }
548
549 /* 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)550 SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
551 void __user *, parent_tidptr, void __user *, child_tidptr,
552 struct pt_regs *, regs)
553 {
554 if (!newsp)
555 newsp = regs->sp;
556 return do_fork(clone_flags, newsp, regs, 0,
557 parent_tidptr, child_tidptr);
558 }
559
560 /*
561 * sys_execve() executes a new program.
562 */
SYSCALL_DEFINE4(execve,const char __user *,path,const char __user * const __user *,argv,const char __user * const __user *,envp,struct pt_regs *,regs)563 SYSCALL_DEFINE4(execve, const char __user *, path,
564 const char __user *const __user *, argv,
565 const char __user *const __user *, envp,
566 struct pt_regs *, regs)
567 {
568 long error;
569 char *filename;
570
571 filename = getname(path);
572 error = PTR_ERR(filename);
573 if (IS_ERR(filename))
574 goto out;
575 error = do_execve(filename, argv, envp, regs);
576 putname(filename);
577 if (error == 0)
578 single_step_execve();
579 out:
580 return error;
581 }
582
583 #ifdef CONFIG_COMPAT
compat_sys_execve(const char __user * path,const compat_uptr_t __user * argv,const compat_uptr_t __user * envp,struct pt_regs * regs)584 long compat_sys_execve(const char __user *path,
585 const compat_uptr_t __user *argv,
586 const compat_uptr_t __user *envp,
587 struct pt_regs *regs)
588 {
589 long error;
590 char *filename;
591
592 filename = getname(path);
593 error = PTR_ERR(filename);
594 if (IS_ERR(filename))
595 goto out;
596 error = compat_do_execve(filename, argv, envp, regs);
597 putname(filename);
598 if (error == 0)
599 single_step_execve();
600 out:
601 return error;
602 }
603 #endif
604
get_wchan(struct task_struct * p)605 unsigned long get_wchan(struct task_struct *p)
606 {
607 struct KBacktraceIterator kbt;
608
609 if (!p || p == current || p->state == TASK_RUNNING)
610 return 0;
611
612 for (KBacktraceIterator_init(&kbt, p, NULL);
613 !KBacktraceIterator_end(&kbt);
614 KBacktraceIterator_next(&kbt)) {
615 if (!in_sched_functions(kbt.it.pc))
616 return kbt.it.pc;
617 }
618
619 return 0;
620 }
621
622 /*
623 * We pass in lr as zero (cleared in kernel_thread) and the caller
624 * part of the backtrace ABI on the stack also zeroed (in copy_thread)
625 * so that backtraces will stop with this function.
626 * Note that we don't use r0, since copy_thread() clears it.
627 */
start_kernel_thread(int dummy,int (* fn)(int),int arg)628 static void start_kernel_thread(int dummy, int (*fn)(int), int arg)
629 {
630 do_exit(fn(arg));
631 }
632
633 /*
634 * Create a kernel thread
635 */
kernel_thread(int (* fn)(void *),void * arg,unsigned long flags)636 int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags)
637 {
638 struct pt_regs regs;
639
640 memset(®s, 0, sizeof(regs));
641 regs.ex1 = PL_ICS_EX1(KERNEL_PL, 0); /* run at kernel PL, no ICS */
642 regs.pc = (long) start_kernel_thread;
643 regs.flags = PT_FLAGS_CALLER_SAVES; /* need to restore r1 and r2 */
644 regs.regs[1] = (long) fn; /* function pointer */
645 regs.regs[2] = (long) arg; /* parameter register */
646
647 /* Ok, create the new process.. */
648 return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s,
649 0, NULL, NULL);
650 }
651 EXPORT_SYMBOL(kernel_thread);
652
653 /* Flush thread state. */
flush_thread(void)654 void flush_thread(void)
655 {
656 /* Nothing */
657 }
658
659 /*
660 * Free current thread data structures etc..
661 */
exit_thread(void)662 void exit_thread(void)
663 {
664 /* Nothing */
665 }
666
show_regs(struct pt_regs * regs)667 void show_regs(struct pt_regs *regs)
668 {
669 struct task_struct *tsk = validate_current();
670 int i;
671
672 pr_err("\n");
673 pr_err(" Pid: %d, comm: %20s, CPU: %d\n",
674 tsk->pid, tsk->comm, smp_processor_id());
675 #ifdef __tilegx__
676 for (i = 0; i < 51; i += 3)
677 pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
678 i, regs->regs[i], i+1, regs->regs[i+1],
679 i+2, regs->regs[i+2]);
680 pr_err(" r51: "REGFMT" r52: "REGFMT" tp : "REGFMT"\n",
681 regs->regs[51], regs->regs[52], regs->tp);
682 pr_err(" sp : "REGFMT" lr : "REGFMT"\n", regs->sp, regs->lr);
683 #else
684 for (i = 0; i < 52; i += 4)
685 pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT
686 " r%-2d: "REGFMT" r%-2d: "REGFMT"\n",
687 i, regs->regs[i], i+1, regs->regs[i+1],
688 i+2, regs->regs[i+2], i+3, regs->regs[i+3]);
689 pr_err(" r52: "REGFMT" tp : "REGFMT" sp : "REGFMT" lr : "REGFMT"\n",
690 regs->regs[52], regs->tp, regs->sp, regs->lr);
691 #endif
692 pr_err(" pc : "REGFMT" ex1: %ld faultnum: %ld\n",
693 regs->pc, regs->ex1, regs->faultnum);
694
695 dump_stack_regs(regs);
696 }
697