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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/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; |
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 | */ |
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 | |
117 | /* |
118 | * Release a thread_info structure |
119 | */ |
120 | void arch_release_thread_info(struct thread_info *info) |
121 | { |
122 | struct single_step_state *step_state = info->step_state; |
123 | |
124 | #ifdef CONFIG_HARDWALL |
125 | /* |
126 | * We free a thread_info from the context of the task that has |
127 | * been scheduled next, so the original task is already dead. |
128 | * Calling deactivate here just frees up the data structures. |
129 | * If the task we're freeing held the last reference to a |
130 | * hardwall fd, it would have been released prior to this point |
131 | * anyway via exit_files(), and the hardwall_task.info pointers |
132 | * would be NULL by now. |
133 | */ |
134 | hardwall_deactivate_all(info->task); |
135 | #endif |
136 | |
137 | if (step_state) { |
138 | |
139 | /* |
140 | * FIXME: we don't munmap step_state->buffer |
141 | * because the mm_struct for this process (info->task->mm) |
142 | * has already been zeroed in exit_mm(). Keeping a |
143 | * reference to it here seems like a bad move, so this |
144 | * means we can't munmap() the buffer, and therefore if we |
145 | * ptrace multiple threads in a process, we will slowly |
146 | * leak user memory. (Note that as soon as the last |
147 | * thread in a process dies, we will reclaim all user |
148 | * memory including single-step buffers in the usual way.) |
149 | * We should either assign a kernel VA to this buffer |
150 | * somehow, or we should associate the buffer(s) with the |
151 | * mm itself so we can clean them up that way. |
152 | */ |
153 | kfree(step_state); |
154 | } |
155 | } |
156 | |
157 | static void save_arch_state(struct thread_struct *t); |
158 | |
159 | int copy_thread(unsigned long clone_flags, unsigned long sp, |
160 | unsigned long stack_size, |
161 | struct task_struct *p, struct pt_regs *regs) |
162 | { |
163 | struct pt_regs *childregs; |
164 | unsigned long ksp; |
165 | |
166 | /* |
167 | * When creating a new kernel thread we pass sp as zero. |
168 | * Assign it to a reasonable value now that we have the stack. |
169 | */ |
170 | if (sp == 0 && regs->ex1 == PL_ICS_EX1(KERNEL_PL, 0)) |
171 | sp = KSTK_TOP(p); |
172 | |
173 | /* |
174 | * Do not clone step state from the parent; each thread |
175 | * must make its own lazily. |
176 | */ |
177 | task_thread_info(p)->step_state = NULL; |
178 | |
179 | /* |
180 | * Start new thread in ret_from_fork so it schedules properly |
181 | * and then return from interrupt like the parent. |
182 | */ |
183 | p->thread.pc = (unsigned long) ret_from_fork; |
184 | |
185 | /* Save user stack top pointer so we can ID the stack vm area later. */ |
186 | p->thread.usp0 = sp; |
187 | |
188 | /* Record the pid of the process that created this one. */ |
189 | p->thread.creator_pid = current->pid; |
190 | |
191 | /* |
192 | * Copy the registers onto the kernel stack so the |
193 | * return-from-interrupt code will reload it into registers. |
194 | */ |
195 | childregs = task_pt_regs(p); |
196 | *childregs = *regs; |
197 | childregs->regs[0] = 0; /* return value is zero */ |
198 | childregs->sp = sp; /* override with new user stack pointer */ |
199 | |
200 | /* |
201 | * If CLONE_SETTLS is set, set "tp" in the new task to "r4", |
202 | * which is passed in as arg #5 to sys_clone(). |
203 | */ |
204 | if (clone_flags & CLONE_SETTLS) |
205 | childregs->tp = regs->regs[4]; |
206 | |
207 | /* |
208 | * Copy the callee-saved registers from the passed pt_regs struct |
209 | * into the context-switch callee-saved registers area. |
210 | * This way when we start the interrupt-return sequence, the |
211 | * callee-save registers will be correctly in registers, which |
212 | * is how we assume the compiler leaves them as we start doing |
213 | * the normal return-from-interrupt path after calling C code. |
214 | * Zero out the C ABI save area to mark the top of the stack. |
215 | */ |
216 | ksp = (unsigned long) childregs; |
217 | ksp -= C_ABI_SAVE_AREA_SIZE; /* interrupt-entry save area */ |
218 | ((long *)ksp)[0] = ((long *)ksp)[1] = 0; |
219 | ksp -= CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long); |
220 | memcpy((void *)ksp, ®s->regs[CALLEE_SAVED_FIRST_REG], |
221 | CALLEE_SAVED_REGS_COUNT * sizeof(unsigned long)); |
222 | ksp -= C_ABI_SAVE_AREA_SIZE; /* __switch_to() save area */ |
223 | ((long *)ksp)[0] = ((long *)ksp)[1] = 0; |
224 | p->thread.ksp = ksp; |
225 | |
226 | #if CHIP_HAS_TILE_DMA() |
227 | /* |
228 | * No DMA in the new thread. We model this on the fact that |
229 | * fork() clears the pending signals, alarms, and aio for the child. |
230 | */ |
231 | memset(&p->thread.tile_dma_state, 0, sizeof(struct tile_dma_state)); |
232 | memset(&p->thread.dma_async_tlb, 0, sizeof(struct async_tlb)); |
233 | #endif |
234 | |
235 | #if CHIP_HAS_SN_PROC() |
236 | /* Likewise, the new thread is not running static processor code. */ |
237 | p->thread.sn_proc_running = 0; |
238 | memset(&p->thread.sn_async_tlb, 0, sizeof(struct async_tlb)); |
239 | #endif |
240 | |
241 | #if CHIP_HAS_PROC_STATUS_SPR() |
242 | /* New thread has its miscellaneous processor state bits clear. */ |
243 | p->thread.proc_status = 0; |
244 | #endif |
245 | |
246 | #ifdef CONFIG_HARDWALL |
247 | /* New thread does not own any networks. */ |
248 | memset(&p->thread.hardwall[0], 0, |
249 | sizeof(struct hardwall_task) * HARDWALL_TYPES); |
250 | #endif |
251 | |
252 | |
253 | /* |
254 | * Start the new thread with the current architecture state |
255 | * (user interrupt masks, etc.). |
256 | */ |
257 | save_arch_state(&p->thread); |
258 | |
259 | return 0; |
260 | } |
261 | |
262 | /* |
263 | * Return "current" if it looks plausible, or else a pointer to a dummy. |
264 | * This can be helpful if we are just trying to emit a clean panic. |
265 | */ |
266 | struct task_struct *validate_current(void) |
267 | { |
268 | static struct task_struct corrupt = { .comm = "<corrupt>" }; |
269 | struct task_struct *tsk = current; |
270 | if (unlikely((unsigned long)tsk < PAGE_OFFSET || |
271 | (high_memory && (void *)tsk > high_memory) || |
272 | ((unsigned long)tsk & (__alignof__(*tsk) - 1)) != 0)) { |
273 | pr_err("Corrupt 'current' %p (sp %#lx)\n", tsk, stack_pointer); |
274 | tsk = &corrupt; |
275 | } |
276 | return tsk; |
277 | } |
278 | |
279 | /* Take and return the pointer to the previous task, for schedule_tail(). */ |
280 | struct task_struct *sim_notify_fork(struct task_struct *prev) |
281 | { |
282 | struct task_struct *tsk = current; |
283 | __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK_PARENT | |
284 | (tsk->thread.creator_pid << _SIM_CONTROL_OPERATOR_BITS)); |
285 | __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_OS_FORK | |
286 | (tsk->pid << _SIM_CONTROL_OPERATOR_BITS)); |
287 | return prev; |
288 | } |
289 | |
290 | int dump_task_regs(struct task_struct *tsk, elf_gregset_t *regs) |
291 | { |
292 | struct pt_regs *ptregs = task_pt_regs(tsk); |
293 | elf_core_copy_regs(regs, ptregs); |
294 | return 1; |
295 | } |
296 | |
297 | #if CHIP_HAS_TILE_DMA() |
298 | |
299 | /* Allow user processes to access the DMA SPRs */ |
300 | void grant_dma_mpls(void) |
301 | { |
302 | #if CONFIG_KERNEL_PL == 2 |
303 | __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1); |
304 | __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1); |
305 | #else |
306 | __insn_mtspr(SPR_MPL_DMA_CPL_SET_0, 1); |
307 | __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_0, 1); |
308 | #endif |
309 | } |
310 | |
311 | /* Forbid user processes from accessing the DMA SPRs */ |
312 | void restrict_dma_mpls(void) |
313 | { |
314 | #if CONFIG_KERNEL_PL == 2 |
315 | __insn_mtspr(SPR_MPL_DMA_CPL_SET_2, 1); |
316 | __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_2, 1); |
317 | #else |
318 | __insn_mtspr(SPR_MPL_DMA_CPL_SET_1, 1); |
319 | __insn_mtspr(SPR_MPL_DMA_NOTIFY_SET_1, 1); |
320 | #endif |
321 | } |
322 | |
323 | /* Pause the DMA engine, then save off its state registers. */ |
324 | static void save_tile_dma_state(struct tile_dma_state *dma) |
325 | { |
326 | unsigned long state = __insn_mfspr(SPR_DMA_USER_STATUS); |
327 | unsigned long post_suspend_state; |
328 | |
329 | /* If we're running, suspend the engine. */ |
330 | if ((state & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) |
331 | __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__SUSPEND_MASK); |
332 | |
333 | /* |
334 | * Wait for the engine to idle, then save regs. Note that we |
335 | * want to record the "running" bit from before suspension, |
336 | * and the "done" bit from after, so that we can properly |
337 | * distinguish a case where the user suspended the engine from |
338 | * the case where the kernel suspended as part of the context |
339 | * swap. |
340 | */ |
341 | do { |
342 | post_suspend_state = __insn_mfspr(SPR_DMA_USER_STATUS); |
343 | } while (post_suspend_state & SPR_DMA_STATUS__BUSY_MASK); |
344 | |
345 | dma->src = __insn_mfspr(SPR_DMA_SRC_ADDR); |
346 | dma->src_chunk = __insn_mfspr(SPR_DMA_SRC_CHUNK_ADDR); |
347 | dma->dest = __insn_mfspr(SPR_DMA_DST_ADDR); |
348 | dma->dest_chunk = __insn_mfspr(SPR_DMA_DST_CHUNK_ADDR); |
349 | dma->strides = __insn_mfspr(SPR_DMA_STRIDE); |
350 | dma->chunk_size = __insn_mfspr(SPR_DMA_CHUNK_SIZE); |
351 | dma->byte = __insn_mfspr(SPR_DMA_BYTE); |
352 | dma->status = (state & SPR_DMA_STATUS__RUNNING_MASK) | |
353 | (post_suspend_state & SPR_DMA_STATUS__DONE_MASK); |
354 | } |
355 | |
356 | /* Restart a DMA that was running before we were context-switched out. */ |
357 | static void restore_tile_dma_state(struct thread_struct *t) |
358 | { |
359 | const struct tile_dma_state *dma = &t->tile_dma_state; |
360 | |
361 | /* |
362 | * The only way to restore the done bit is to run a zero |
363 | * length transaction. |
364 | */ |
365 | if ((dma->status & SPR_DMA_STATUS__DONE_MASK) && |
366 | !(__insn_mfspr(SPR_DMA_USER_STATUS) & SPR_DMA_STATUS__DONE_MASK)) { |
367 | __insn_mtspr(SPR_DMA_BYTE, 0); |
368 | __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK); |
369 | while (__insn_mfspr(SPR_DMA_USER_STATUS) & |
370 | SPR_DMA_STATUS__BUSY_MASK) |
371 | ; |
372 | } |
373 | |
374 | __insn_mtspr(SPR_DMA_SRC_ADDR, dma->src); |
375 | __insn_mtspr(SPR_DMA_SRC_CHUNK_ADDR, dma->src_chunk); |
376 | __insn_mtspr(SPR_DMA_DST_ADDR, dma->dest); |
377 | __insn_mtspr(SPR_DMA_DST_CHUNK_ADDR, dma->dest_chunk); |
378 | __insn_mtspr(SPR_DMA_STRIDE, dma->strides); |
379 | __insn_mtspr(SPR_DMA_CHUNK_SIZE, dma->chunk_size); |
380 | __insn_mtspr(SPR_DMA_BYTE, dma->byte); |
381 | |
382 | /* |
383 | * Restart the engine if we were running and not done. |
384 | * Clear a pending async DMA fault that we were waiting on return |
385 | * to user space to execute, since we expect the DMA engine |
386 | * to regenerate those faults for us now. Note that we don't |
387 | * try to clear the TIF_ASYNC_TLB flag, since it's relatively |
388 | * harmless if set, and it covers both DMA and the SN processor. |
389 | */ |
390 | if ((dma->status & DMA_STATUS_MASK) == SPR_DMA_STATUS__RUNNING_MASK) { |
391 | t->dma_async_tlb.fault_num = 0; |
392 | __insn_mtspr(SPR_DMA_CTR, SPR_DMA_CTR__REQUEST_MASK); |
393 | } |
394 | } |
395 | |
396 | #endif |
397 | |
398 | static void save_arch_state(struct thread_struct *t) |
399 | { |
400 | #if CHIP_HAS_SPLIT_INTR_MASK() |
401 | t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0_0) | |
402 | ((u64)__insn_mfspr(SPR_INTERRUPT_MASK_0_1) << 32); |
403 | #else |
404 | t->interrupt_mask = __insn_mfspr(SPR_INTERRUPT_MASK_0); |
405 | #endif |
406 | t->ex_context[0] = __insn_mfspr(SPR_EX_CONTEXT_0_0); |
407 | t->ex_context[1] = __insn_mfspr(SPR_EX_CONTEXT_0_1); |
408 | t->system_save[0] = __insn_mfspr(SPR_SYSTEM_SAVE_0_0); |
409 | t->system_save[1] = __insn_mfspr(SPR_SYSTEM_SAVE_0_1); |
410 | t->system_save[2] = __insn_mfspr(SPR_SYSTEM_SAVE_0_2); |
411 | t->system_save[3] = __insn_mfspr(SPR_SYSTEM_SAVE_0_3); |
412 | t->intctrl_0 = __insn_mfspr(SPR_INTCTRL_0_STATUS); |
413 | #if CHIP_HAS_PROC_STATUS_SPR() |
414 | t->proc_status = __insn_mfspr(SPR_PROC_STATUS); |
415 | #endif |
416 | #if !CHIP_HAS_FIXED_INTVEC_BASE() |
417 | t->interrupt_vector_base = __insn_mfspr(SPR_INTERRUPT_VECTOR_BASE_0); |
418 | #endif |
419 | #if CHIP_HAS_TILE_RTF_HWM() |
420 | t->tile_rtf_hwm = __insn_mfspr(SPR_TILE_RTF_HWM); |
421 | #endif |
422 | #if CHIP_HAS_DSTREAM_PF() |
423 | t->dstream_pf = __insn_mfspr(SPR_DSTREAM_PF); |
424 | #endif |
425 | } |
426 | |
427 | static void restore_arch_state(const struct thread_struct *t) |
428 | { |
429 | #if CHIP_HAS_SPLIT_INTR_MASK() |
430 | __insn_mtspr(SPR_INTERRUPT_MASK_0_0, (u32) t->interrupt_mask); |
431 | __insn_mtspr(SPR_INTERRUPT_MASK_0_1, t->interrupt_mask >> 32); |
432 | #else |
433 | __insn_mtspr(SPR_INTERRUPT_MASK_0, t->interrupt_mask); |
434 | #endif |
435 | __insn_mtspr(SPR_EX_CONTEXT_0_0, t->ex_context[0]); |
436 | __insn_mtspr(SPR_EX_CONTEXT_0_1, t->ex_context[1]); |
437 | __insn_mtspr(SPR_SYSTEM_SAVE_0_0, t->system_save[0]); |
438 | __insn_mtspr(SPR_SYSTEM_SAVE_0_1, t->system_save[1]); |
439 | __insn_mtspr(SPR_SYSTEM_SAVE_0_2, t->system_save[2]); |
440 | __insn_mtspr(SPR_SYSTEM_SAVE_0_3, t->system_save[3]); |
441 | __insn_mtspr(SPR_INTCTRL_0_STATUS, t->intctrl_0); |
442 | #if CHIP_HAS_PROC_STATUS_SPR() |
443 | __insn_mtspr(SPR_PROC_STATUS, t->proc_status); |
444 | #endif |
445 | #if !CHIP_HAS_FIXED_INTVEC_BASE() |
446 | __insn_mtspr(SPR_INTERRUPT_VECTOR_BASE_0, t->interrupt_vector_base); |
447 | #endif |
448 | #if CHIP_HAS_TILE_RTF_HWM() |
449 | __insn_mtspr(SPR_TILE_RTF_HWM, t->tile_rtf_hwm); |
450 | #endif |
451 | #if CHIP_HAS_DSTREAM_PF() |
452 | __insn_mtspr(SPR_DSTREAM_PF, t->dstream_pf); |
453 | #endif |
454 | } |
455 | |
456 | |
457 | void _prepare_arch_switch(struct task_struct *next) |
458 | { |
459 | #if CHIP_HAS_SN_PROC() |
460 | int snctl; |
461 | #endif |
462 | #if CHIP_HAS_TILE_DMA() |
463 | struct tile_dma_state *dma = ¤t->thread.tile_dma_state; |
464 | if (dma->enabled) |
465 | save_tile_dma_state(dma); |
466 | #endif |
467 | #if CHIP_HAS_SN_PROC() |
468 | /* |
469 | * Suspend the static network processor if it was running. |
470 | * We do not suspend the fabric itself, just like we don't |
471 | * try to suspend the UDN. |
472 | */ |
473 | snctl = __insn_mfspr(SPR_SNCTL); |
474 | current->thread.sn_proc_running = |
475 | (snctl & SPR_SNCTL__FRZPROC_MASK) == 0; |
476 | if (current->thread.sn_proc_running) |
477 | __insn_mtspr(SPR_SNCTL, snctl | SPR_SNCTL__FRZPROC_MASK); |
478 | #endif |
479 | } |
480 | |
481 | |
482 | struct task_struct *__sched _switch_to(struct task_struct *prev, |
483 | struct task_struct *next) |
484 | { |
485 | /* DMA state is already saved; save off other arch state. */ |
486 | save_arch_state(&prev->thread); |
487 | |
488 | #if CHIP_HAS_TILE_DMA() |
489 | /* |
490 | * Restore DMA in new task if desired. |
491 | * Note that it is only safe to restart here since interrupts |
492 | * are disabled, so we can't take any DMATLB miss or access |
493 | * interrupts before we have finished switching stacks. |
494 | */ |
495 | if (next->thread.tile_dma_state.enabled) { |
496 | restore_tile_dma_state(&next->thread); |
497 | grant_dma_mpls(); |
498 | } else { |
499 | restrict_dma_mpls(); |
500 | } |
501 | #endif |
502 | |
503 | /* Restore other arch state. */ |
504 | restore_arch_state(&next->thread); |
505 | |
506 | #if CHIP_HAS_SN_PROC() |
507 | /* |
508 | * Restart static network processor in the new process |
509 | * if it was running before. |
510 | */ |
511 | if (next->thread.sn_proc_running) { |
512 | int snctl = __insn_mfspr(SPR_SNCTL); |
513 | __insn_mtspr(SPR_SNCTL, snctl & ~SPR_SNCTL__FRZPROC_MASK); |
514 | } |
515 | #endif |
516 | |
517 | #ifdef CONFIG_HARDWALL |
518 | /* Enable or disable access to the network registers appropriately. */ |
519 | hardwall_switch_tasks(prev, next); |
520 | #endif |
521 | |
522 | /* |
523 | * Switch kernel SP, PC, and callee-saved registers. |
524 | * In the context of the new task, return the old task pointer |
525 | * (i.e. the task that actually called __switch_to). |
526 | * Pass the value to use for SYSTEM_SAVE_K_0 when we reset our sp. |
527 | */ |
528 | return __switch_to(prev, next, next_current_ksp0(next)); |
529 | } |
530 | |
531 | /* |
532 | * This routine is called on return from interrupt if any of the |
533 | * TIF_WORK_MASK flags are set in thread_info->flags. It is |
534 | * entered with interrupts disabled so we don't miss an event |
535 | * that modified the thread_info flags. If any flag is set, we |
536 | * handle it and return, and the calling assembly code will |
537 | * re-disable interrupts, reload the thread flags, and call back |
538 | * if more flags need to be handled. |
539 | * |
540 | * We return whether we need to check the thread_info flags again |
541 | * or not. Note that we don't clear TIF_SINGLESTEP here, so it's |
542 | * important that it be tested last, and then claim that we don't |
543 | * need to recheck the flags. |
544 | */ |
545 | int do_work_pending(struct pt_regs *regs, u32 thread_info_flags) |
546 | { |
547 | /* If we enter in kernel mode, do nothing and exit the caller loop. */ |
548 | if (!user_mode(regs)) |
549 | return 0; |
550 | |
551 | if (thread_info_flags & _TIF_NEED_RESCHED) { |
552 | schedule(); |
553 | return 1; |
554 | } |
555 | #if CHIP_HAS_TILE_DMA() || CHIP_HAS_SN_PROC() |
556 | if (thread_info_flags & _TIF_ASYNC_TLB) { |
557 | do_async_page_fault(regs); |
558 | return 1; |
559 | } |
560 | #endif |
561 | if (thread_info_flags & _TIF_SIGPENDING) { |
562 | do_signal(regs); |
563 | return 1; |
564 | } |
565 | if (thread_info_flags & _TIF_NOTIFY_RESUME) { |
566 | clear_thread_flag(TIF_NOTIFY_RESUME); |
567 | tracehook_notify_resume(regs); |
568 | return 1; |
569 | } |
570 | if (thread_info_flags & _TIF_SINGLESTEP) { |
571 | single_step_once(regs); |
572 | return 0; |
573 | } |
574 | panic("work_pending: bad flags %#x\n", thread_info_flags); |
575 | } |
576 | |
577 | /* Note there is an implicit fifth argument if (clone_flags & CLONE_SETTLS). */ |
578 | SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp, |
579 | void __user *, parent_tidptr, void __user *, child_tidptr, |
580 | struct pt_regs *, regs) |
581 | { |
582 | if (!newsp) |
583 | newsp = regs->sp; |
584 | return do_fork(clone_flags, newsp, regs, 0, |
585 | parent_tidptr, child_tidptr); |
586 | } |
587 | |
588 | /* |
589 | * sys_execve() executes a new program. |
590 | */ |
591 | SYSCALL_DEFINE4(execve, const char __user *, path, |
592 | const char __user *const __user *, argv, |
593 | const char __user *const __user *, envp, |
594 | struct pt_regs *, regs) |
595 | { |
596 | long error; |
597 | char *filename; |
598 | |
599 | filename = getname(path); |
600 | error = PTR_ERR(filename); |
601 | if (IS_ERR(filename)) |
602 | goto out; |
603 | error = do_execve(filename, argv, envp, regs); |
604 | putname(filename); |
605 | if (error == 0) |
606 | single_step_execve(); |
607 | out: |
608 | return error; |
609 | } |
610 | |
611 | #ifdef CONFIG_COMPAT |
612 | long compat_sys_execve(const char __user *path, |
613 | compat_uptr_t __user *argv, |
614 | compat_uptr_t __user *envp, |
615 | struct pt_regs *regs) |
616 | { |
617 | long error; |
618 | char *filename; |
619 | |
620 | filename = getname(path); |
621 | error = PTR_ERR(filename); |
622 | if (IS_ERR(filename)) |
623 | goto out; |
624 | error = compat_do_execve(filename, argv, envp, regs); |
625 | putname(filename); |
626 | if (error == 0) |
627 | single_step_execve(); |
628 | out: |
629 | return error; |
630 | } |
631 | #endif |
632 | |
633 | unsigned long get_wchan(struct task_struct *p) |
634 | { |
635 | struct KBacktraceIterator kbt; |
636 | |
637 | if (!p || p == current || p->state == TASK_RUNNING) |
638 | return 0; |
639 | |
640 | for (KBacktraceIterator_init(&kbt, p, NULL); |
641 | !KBacktraceIterator_end(&kbt); |
642 | KBacktraceIterator_next(&kbt)) { |
643 | if (!in_sched_functions(kbt.it.pc)) |
644 | return kbt.it.pc; |
645 | } |
646 | |
647 | return 0; |
648 | } |
649 | |
650 | /* |
651 | * We pass in lr as zero (cleared in kernel_thread) and the caller |
652 | * part of the backtrace ABI on the stack also zeroed (in copy_thread) |
653 | * so that backtraces will stop with this function. |
654 | * Note that we don't use r0, since copy_thread() clears it. |
655 | */ |
656 | static void start_kernel_thread(int dummy, int (*fn)(int), int arg) |
657 | { |
658 | do_exit(fn(arg)); |
659 | } |
660 | |
661 | /* |
662 | * Create a kernel thread |
663 | */ |
664 | int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) |
665 | { |
666 | struct pt_regs regs; |
667 | |
668 | memset(®s, 0, sizeof(regs)); |
669 | regs.ex1 = PL_ICS_EX1(KERNEL_PL, 0); /* run at kernel PL, no ICS */ |
670 | regs.pc = (long) start_kernel_thread; |
671 | regs.flags = PT_FLAGS_CALLER_SAVES; /* need to restore r1 and r2 */ |
672 | regs.regs[1] = (long) fn; /* function pointer */ |
673 | regs.regs[2] = (long) arg; /* parameter register */ |
674 | |
675 | /* Ok, create the new process.. */ |
676 | return do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, ®s, |
677 | 0, NULL, NULL); |
678 | } |
679 | EXPORT_SYMBOL(kernel_thread); |
680 | |
681 | /* Flush thread state. */ |
682 | void flush_thread(void) |
683 | { |
684 | /* Nothing */ |
685 | } |
686 | |
687 | /* |
688 | * Free current thread data structures etc.. |
689 | */ |
690 | void exit_thread(void) |
691 | { |
692 | /* Nothing */ |
693 | } |
694 | |
695 | void show_regs(struct pt_regs *regs) |
696 | { |
697 | struct task_struct *tsk = validate_current(); |
698 | int i; |
699 | |
700 | pr_err("\n"); |
701 | pr_err(" Pid: %d, comm: %20s, CPU: %d\n", |
702 | tsk->pid, tsk->comm, smp_processor_id()); |
703 | #ifdef __tilegx__ |
704 | for (i = 0; i < 51; i += 3) |
705 | pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT" r%-2d: "REGFMT"\n", |
706 | i, regs->regs[i], i+1, regs->regs[i+1], |
707 | i+2, regs->regs[i+2]); |
708 | pr_err(" r51: "REGFMT" r52: "REGFMT" tp : "REGFMT"\n", |
709 | regs->regs[51], regs->regs[52], regs->tp); |
710 | pr_err(" sp : "REGFMT" lr : "REGFMT"\n", regs->sp, regs->lr); |
711 | #else |
712 | for (i = 0; i < 52; i += 4) |
713 | pr_err(" r%-2d: "REGFMT" r%-2d: "REGFMT |
714 | " r%-2d: "REGFMT" r%-2d: "REGFMT"\n", |
715 | i, regs->regs[i], i+1, regs->regs[i+1], |
716 | i+2, regs->regs[i+2], i+3, regs->regs[i+3]); |
717 | pr_err(" r52: "REGFMT" tp : "REGFMT" sp : "REGFMT" lr : "REGFMT"\n", |
718 | regs->regs[52], regs->tp, regs->sp, regs->lr); |
719 | #endif |
720 | pr_err(" pc : "REGFMT" ex1: %ld faultnum: %ld\n", |
721 | regs->pc, regs->ex1, regs->faultnum); |
722 | |
723 | dump_stack_regs(regs); |
724 | } |
725 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
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v3.9