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1 | /* |
2 | * Tracing hooks |
3 | * |
4 | * Copyright (C) 2008-2009 Red Hat, Inc. All rights reserved. |
5 | * |
6 | * This copyrighted material is made available to anyone wishing to use, |
7 | * modify, copy, or redistribute it subject to the terms and conditions |
8 | * of the GNU General Public License v.2. |
9 | * |
10 | * This file defines hook entry points called by core code where |
11 | * user tracing/debugging support might need to do something. These |
12 | * entry points are called tracehook_*(). Each hook declared below |
13 | * has a detailed kerneldoc comment giving the context (locking et |
14 | * al) from which it is called, and the meaning of its return value. |
15 | * |
16 | * Each function here typically has only one call site, so it is ok |
17 | * to have some nontrivial tracehook_*() inlines. In all cases, the |
18 | * fast path when no tracing is enabled should be very short. |
19 | * |
20 | * The purpose of this file and the tracehook_* layer is to consolidate |
21 | * the interface that the kernel core and arch code uses to enable any |
22 | * user debugging or tracing facility (such as ptrace). The interfaces |
23 | * here are carefully documented so that maintainers of core and arch |
24 | * code do not need to think about the implementation details of the |
25 | * tracing facilities. Likewise, maintainers of the tracing code do not |
26 | * need to understand all the calling core or arch code in detail, just |
27 | * documented circumstances of each call, such as locking conditions. |
28 | * |
29 | * If the calling core code changes so that locking is different, then |
30 | * it is ok to change the interface documented here. The maintainer of |
31 | * core code changing should notify the maintainers of the tracing code |
32 | * that they need to work out the change. |
33 | * |
34 | * Some tracehook_*() inlines take arguments that the current tracing |
35 | * implementations might not necessarily use. These function signatures |
36 | * are chosen to pass in all the information that is on hand in the |
37 | * caller and might conceivably be relevant to a tracer, so that the |
38 | * core code won't have to be updated when tracing adds more features. |
39 | * If a call site changes so that some of those parameters are no longer |
40 | * already on hand without extra work, then the tracehook_* interface |
41 | * can change so there is no make-work burden on the core code. The |
42 | * maintainer of core code changing should notify the maintainers of the |
43 | * tracing code that they need to work out the change. |
44 | */ |
45 | |
46 | #ifndef _LINUX_TRACEHOOK_H |
47 | #define _LINUX_TRACEHOOK_H 1 |
48 | |
49 | #include <linux/sched.h> |
50 | #include <linux/ptrace.h> |
51 | #include <linux/security.h> |
52 | struct linux_binprm; |
53 | |
54 | /** |
55 | * tracehook_expect_breakpoints - guess if task memory might be touched |
56 | * @task: current task, making a new mapping |
57 | * |
58 | * Return nonzero if @task is expected to want breakpoint insertion in |
59 | * its memory at some point. A zero return is no guarantee it won't |
60 | * be done, but this is a hint that it's known to be likely. |
61 | * |
62 | * May be called with @task->mm->mmap_sem held for writing. |
63 | */ |
64 | static inline int tracehook_expect_breakpoints(struct task_struct *task) |
65 | { |
66 | return (task_ptrace(task) & PT_PTRACED) != 0; |
67 | } |
68 | |
69 | /* |
70 | * ptrace report for syscall entry and exit looks identical. |
71 | */ |
72 | static inline void ptrace_report_syscall(struct pt_regs *regs) |
73 | { |
74 | int ptrace = task_ptrace(current); |
75 | |
76 | if (!(ptrace & PT_PTRACED)) |
77 | return; |
78 | |
79 | ptrace_notify(SIGTRAP | ((ptrace & PT_TRACESYSGOOD) ? 0x80 : 0)); |
80 | |
81 | /* |
82 | * this isn't the same as continuing with a signal, but it will do |
83 | * for normal use. strace only continues with a signal if the |
84 | * stopping signal is not SIGTRAP. -brl |
85 | */ |
86 | if (current->exit_code) { |
87 | send_sig(current->exit_code, current, 1); |
88 | current->exit_code = 0; |
89 | } |
90 | } |
91 | |
92 | /** |
93 | * tracehook_report_syscall_entry - task is about to attempt a system call |
94 | * @regs: user register state of current task |
95 | * |
96 | * This will be called if %TIF_SYSCALL_TRACE has been set, when the |
97 | * current task has just entered the kernel for a system call. |
98 | * Full user register state is available here. Changing the values |
99 | * in @regs can affect the system call number and arguments to be tried. |
100 | * It is safe to block here, preventing the system call from beginning. |
101 | * |
102 | * Returns zero normally, or nonzero if the calling arch code should abort |
103 | * the system call. That must prevent normal entry so no system call is |
104 | * made. If @task ever returns to user mode after this, its register state |
105 | * is unspecified, but should be something harmless like an %ENOSYS error |
106 | * return. It should preserve enough information so that syscall_rollback() |
107 | * can work (see asm-generic/syscall.h). |
108 | * |
109 | * Called without locks, just after entering kernel mode. |
110 | */ |
111 | static inline __must_check int tracehook_report_syscall_entry( |
112 | struct pt_regs *regs) |
113 | { |
114 | ptrace_report_syscall(regs); |
115 | return 0; |
116 | } |
117 | |
118 | /** |
119 | * tracehook_report_syscall_exit - task has just finished a system call |
120 | * @regs: user register state of current task |
121 | * @step: nonzero if simulating single-step or block-step |
122 | * |
123 | * This will be called if %TIF_SYSCALL_TRACE has been set, when the |
124 | * current task has just finished an attempted system call. Full |
125 | * user register state is available here. It is safe to block here, |
126 | * preventing signals from being processed. |
127 | * |
128 | * If @step is nonzero, this report is also in lieu of the normal |
129 | * trap that would follow the system call instruction because |
130 | * user_enable_block_step() or user_enable_single_step() was used. |
131 | * In this case, %TIF_SYSCALL_TRACE might not be set. |
132 | * |
133 | * Called without locks, just before checking for pending signals. |
134 | */ |
135 | static inline void tracehook_report_syscall_exit(struct pt_regs *regs, int step) |
136 | { |
137 | if (step) { |
138 | siginfo_t info; |
139 | user_single_step_siginfo(current, regs, &info); |
140 | force_sig_info(SIGTRAP, &info, current); |
141 | return; |
142 | } |
143 | |
144 | ptrace_report_syscall(regs); |
145 | } |
146 | |
147 | /** |
148 | * tracehook_unsafe_exec - check for exec declared unsafe due to tracing |
149 | * @task: current task doing exec |
150 | * |
151 | * Return %LSM_UNSAFE_* bits applied to an exec because of tracing. |
152 | * |
153 | * @task->cred_guard_mutex is held by the caller through the do_execve(). |
154 | */ |
155 | static inline int tracehook_unsafe_exec(struct task_struct *task) |
156 | { |
157 | int unsafe = 0; |
158 | int ptrace = task_ptrace(task); |
159 | if (ptrace & PT_PTRACED) { |
160 | if (ptrace & PT_PTRACE_CAP) |
161 | unsafe |= LSM_UNSAFE_PTRACE_CAP; |
162 | else |
163 | unsafe |= LSM_UNSAFE_PTRACE; |
164 | } |
165 | return unsafe; |
166 | } |
167 | |
168 | /** |
169 | * tracehook_tracer_task - return the task that is tracing the given task |
170 | * @tsk: task to consider |
171 | * |
172 | * Returns NULL if noone is tracing @task, or the &struct task_struct |
173 | * pointer to its tracer. |
174 | * |
175 | * Must called under rcu_read_lock(). The pointer returned might be kept |
176 | * live only by RCU. During exec, this may be called with task_lock() |
177 | * held on @task, still held from when tracehook_unsafe_exec() was called. |
178 | */ |
179 | static inline struct task_struct *tracehook_tracer_task(struct task_struct *tsk) |
180 | { |
181 | if (task_ptrace(tsk) & PT_PTRACED) |
182 | return rcu_dereference(tsk->parent); |
183 | return NULL; |
184 | } |
185 | |
186 | /** |
187 | * tracehook_report_exec - a successful exec was completed |
188 | * @fmt: &struct linux_binfmt that performed the exec |
189 | * @bprm: &struct linux_binprm containing exec details |
190 | * @regs: user-mode register state |
191 | * |
192 | * An exec just completed, we are shortly going to return to user mode. |
193 | * The freshly initialized register state can be seen and changed in @regs. |
194 | * The name, file and other pointers in @bprm are still on hand to be |
195 | * inspected, but will be freed as soon as this returns. |
196 | * |
197 | * Called with no locks, but with some kernel resources held live |
198 | * and a reference on @fmt->module. |
199 | */ |
200 | static inline void tracehook_report_exec(struct linux_binfmt *fmt, |
201 | struct linux_binprm *bprm, |
202 | struct pt_regs *regs) |
203 | { |
204 | if (!ptrace_event(PT_TRACE_EXEC, PTRACE_EVENT_EXEC, 0) && |
205 | unlikely(task_ptrace(current) & PT_PTRACED)) |
206 | send_sig(SIGTRAP, current, 0); |
207 | } |
208 | |
209 | /** |
210 | * tracehook_report_exit - task has begun to exit |
211 | * @exit_code: pointer to value destined for @current->exit_code |
212 | * |
213 | * @exit_code points to the value passed to do_exit(), which tracing |
214 | * might change here. This is almost the first thing in do_exit(), |
215 | * before freeing any resources or setting the %PF_EXITING flag. |
216 | * |
217 | * Called with no locks held. |
218 | */ |
219 | static inline void tracehook_report_exit(long *exit_code) |
220 | { |
221 | ptrace_event(PT_TRACE_EXIT, PTRACE_EVENT_EXIT, *exit_code); |
222 | } |
223 | |
224 | /** |
225 | * tracehook_prepare_clone - prepare for new child to be cloned |
226 | * @clone_flags: %CLONE_* flags from clone/fork/vfork system call |
227 | * |
228 | * This is called before a new user task is to be cloned. |
229 | * Its return value will be passed to tracehook_finish_clone(). |
230 | * |
231 | * Called with no locks held. |
232 | */ |
233 | static inline int tracehook_prepare_clone(unsigned clone_flags) |
234 | { |
235 | if (clone_flags & CLONE_UNTRACED) |
236 | return 0; |
237 | |
238 | if (clone_flags & CLONE_VFORK) { |
239 | if (current->ptrace & PT_TRACE_VFORK) |
240 | return PTRACE_EVENT_VFORK; |
241 | } else if ((clone_flags & CSIGNAL) != SIGCHLD) { |
242 | if (current->ptrace & PT_TRACE_CLONE) |
243 | return PTRACE_EVENT_CLONE; |
244 | } else if (current->ptrace & PT_TRACE_FORK) |
245 | return PTRACE_EVENT_FORK; |
246 | |
247 | return 0; |
248 | } |
249 | |
250 | /** |
251 | * tracehook_finish_clone - new child created and being attached |
252 | * @child: new child task |
253 | * @clone_flags: %CLONE_* flags from clone/fork/vfork system call |
254 | * @trace: return value from tracehook_prepare_clone() |
255 | * |
256 | * This is called immediately after adding @child to its parent's children list. |
257 | * The @trace value is that returned by tracehook_prepare_clone(). |
258 | * |
259 | * Called with current's siglock and write_lock_irq(&tasklist_lock) held. |
260 | */ |
261 | static inline void tracehook_finish_clone(struct task_struct *child, |
262 | unsigned long clone_flags, int trace) |
263 | { |
264 | ptrace_init_task(child, (clone_flags & CLONE_PTRACE) || trace); |
265 | } |
266 | |
267 | /** |
268 | * tracehook_report_clone - in parent, new child is about to start running |
269 | * @regs: parent's user register state |
270 | * @clone_flags: flags from parent's system call |
271 | * @pid: new child's PID in the parent's namespace |
272 | * @child: new child task |
273 | * |
274 | * Called after a child is set up, but before it has been started running. |
275 | * This is not a good place to block, because the child has not started |
276 | * yet. Suspend the child here if desired, and then block in |
277 | * tracehook_report_clone_complete(). This must prevent the child from |
278 | * self-reaping if tracehook_report_clone_complete() uses the @child |
279 | * pointer; otherwise it might have died and been released by the time |
280 | * tracehook_report_clone_complete() is called. |
281 | * |
282 | * Called with no locks held, but the child cannot run until this returns. |
283 | */ |
284 | static inline void tracehook_report_clone(struct pt_regs *regs, |
285 | unsigned long clone_flags, |
286 | pid_t pid, struct task_struct *child) |
287 | { |
288 | if (unlikely(task_ptrace(child))) { |
289 | /* |
290 | * It doesn't matter who attached/attaching to this |
291 | * task, the pending SIGSTOP is right in any case. |
292 | */ |
293 | sigaddset(&child->pending.signal, SIGSTOP); |
294 | set_tsk_thread_flag(child, TIF_SIGPENDING); |
295 | } |
296 | } |
297 | |
298 | /** |
299 | * tracehook_report_clone_complete - new child is running |
300 | * @trace: return value from tracehook_prepare_clone() |
301 | * @regs: parent's user register state |
302 | * @clone_flags: flags from parent's system call |
303 | * @pid: new child's PID in the parent's namespace |
304 | * @child: child task, already running |
305 | * |
306 | * This is called just after the child has started running. This is |
307 | * just before the clone/fork syscall returns, or blocks for vfork |
308 | * child completion if @clone_flags has the %CLONE_VFORK bit set. |
309 | * The @child pointer may be invalid if a self-reaping child died and |
310 | * tracehook_report_clone() took no action to prevent it from self-reaping. |
311 | * |
312 | * Called with no locks held. |
313 | */ |
314 | static inline void tracehook_report_clone_complete(int trace, |
315 | struct pt_regs *regs, |
316 | unsigned long clone_flags, |
317 | pid_t pid, |
318 | struct task_struct *child) |
319 | { |
320 | if (unlikely(trace)) |
321 | ptrace_event(0, trace, pid); |
322 | } |
323 | |
324 | /** |
325 | * tracehook_report_vfork_done - vfork parent's child has exited or exec'd |
326 | * @child: child task, already running |
327 | * @pid: new child's PID in the parent's namespace |
328 | * |
329 | * Called after a %CLONE_VFORK parent has waited for the child to complete. |
330 | * The clone/vfork system call will return immediately after this. |
331 | * The @child pointer may be invalid if a self-reaping child died and |
332 | * tracehook_report_clone() took no action to prevent it from self-reaping. |
333 | * |
334 | * Called with no locks held. |
335 | */ |
336 | static inline void tracehook_report_vfork_done(struct task_struct *child, |
337 | pid_t pid) |
338 | { |
339 | ptrace_event(PT_TRACE_VFORK_DONE, PTRACE_EVENT_VFORK_DONE, pid); |
340 | } |
341 | |
342 | /** |
343 | * tracehook_prepare_release_task - task is being reaped, clean up tracing |
344 | * @task: task in %EXIT_DEAD state |
345 | * |
346 | * This is called in release_task() just before @task gets finally reaped |
347 | * and freed. This would be the ideal place to remove and clean up any |
348 | * tracing-related state for @task. |
349 | * |
350 | * Called with no locks held. |
351 | */ |
352 | static inline void tracehook_prepare_release_task(struct task_struct *task) |
353 | { |
354 | } |
355 | |
356 | /** |
357 | * tracehook_finish_release_task - final tracing clean-up |
358 | * @task: task in %EXIT_DEAD state |
359 | * |
360 | * This is called in release_task() when @task is being in the middle of |
361 | * being reaped. After this, there must be no tracing entanglements. |
362 | * |
363 | * Called with write_lock_irq(&tasklist_lock) held. |
364 | */ |
365 | static inline void tracehook_finish_release_task(struct task_struct *task) |
366 | { |
367 | ptrace_release_task(task); |
368 | } |
369 | |
370 | /** |
371 | * tracehook_signal_handler - signal handler setup is complete |
372 | * @sig: number of signal being delivered |
373 | * @info: siginfo_t of signal being delivered |
374 | * @ka: sigaction setting that chose the handler |
375 | * @regs: user register state |
376 | * @stepping: nonzero if debugger single-step or block-step in use |
377 | * |
378 | * Called by the arch code after a signal handler has been set up. |
379 | * Register and stack state reflects the user handler about to run. |
380 | * Signal mask changes have already been made. |
381 | * |
382 | * Called without locks, shortly before returning to user mode |
383 | * (or handling more signals). |
384 | */ |
385 | static inline void tracehook_signal_handler(int sig, siginfo_t *info, |
386 | const struct k_sigaction *ka, |
387 | struct pt_regs *regs, int stepping) |
388 | { |
389 | if (stepping) |
390 | ptrace_notify(SIGTRAP); |
391 | } |
392 | |
393 | /** |
394 | * tracehook_consider_ignored_signal - suppress short-circuit of ignored signal |
395 | * @task: task receiving the signal |
396 | * @sig: signal number being sent |
397 | * |
398 | * Return zero iff tracing doesn't care to examine this ignored signal, |
399 | * so it can short-circuit normal delivery and never even get queued. |
400 | * |
401 | * Called with @task->sighand->siglock held. |
402 | */ |
403 | static inline int tracehook_consider_ignored_signal(struct task_struct *task, |
404 | int sig) |
405 | { |
406 | return (task_ptrace(task) & PT_PTRACED) != 0; |
407 | } |
408 | |
409 | /** |
410 | * tracehook_consider_fatal_signal - suppress special handling of fatal signal |
411 | * @task: task receiving the signal |
412 | * @sig: signal number being sent |
413 | * |
414 | * Return nonzero to prevent special handling of this termination signal. |
415 | * Normally handler for signal is %SIG_DFL. It can be %SIG_IGN if @sig is |
416 | * ignored, in which case force_sig() is about to reset it to %SIG_DFL. |
417 | * When this returns zero, this signal might cause a quick termination |
418 | * that does not give the debugger a chance to intercept the signal. |
419 | * |
420 | * Called with or without @task->sighand->siglock held. |
421 | */ |
422 | static inline int tracehook_consider_fatal_signal(struct task_struct *task, |
423 | int sig) |
424 | { |
425 | return (task_ptrace(task) & PT_PTRACED) != 0; |
426 | } |
427 | |
428 | /** |
429 | * tracehook_force_sigpending - let tracing force signal_pending(current) on |
430 | * |
431 | * Called when recomputing our signal_pending() flag. Return nonzero |
432 | * to force the signal_pending() flag on, so that tracehook_get_signal() |
433 | * will be called before the next return to user mode. |
434 | * |
435 | * Called with @current->sighand->siglock held. |
436 | */ |
437 | static inline int tracehook_force_sigpending(void) |
438 | { |
439 | return 0; |
440 | } |
441 | |
442 | /** |
443 | * tracehook_get_signal - deliver synthetic signal to traced task |
444 | * @task: @current |
445 | * @regs: task_pt_regs(@current) |
446 | * @info: details of synthetic signal |
447 | * @return_ka: sigaction for synthetic signal |
448 | * |
449 | * Return zero to check for a real pending signal normally. |
450 | * Return -1 after releasing the siglock to repeat the check. |
451 | * Return a signal number to induce an artifical signal delivery, |
452 | * setting *@info and *@return_ka to specify its details and behavior. |
453 | * |
454 | * The @return_ka->sa_handler value controls the disposition of the |
455 | * signal, no matter the signal number. For %SIG_DFL, the return value |
456 | * is a representative signal to indicate the behavior (e.g. %SIGTERM |
457 | * for death, %SIGQUIT for core dump, %SIGSTOP for job control stop, |
458 | * %SIGTSTP for stop unless in an orphaned pgrp), but the signal number |
459 | * reported will be @info->si_signo instead. |
460 | * |
461 | * Called with @task->sighand->siglock held, before dequeuing pending signals. |
462 | */ |
463 | static inline int tracehook_get_signal(struct task_struct *task, |
464 | struct pt_regs *regs, |
465 | siginfo_t *info, |
466 | struct k_sigaction *return_ka) |
467 | { |
468 | return 0; |
469 | } |
470 | |
471 | /** |
472 | * tracehook_notify_jctl - report about job control stop/continue |
473 | * @notify: zero, %CLD_STOPPED or %CLD_CONTINUED |
474 | * @why: %CLD_STOPPED or %CLD_CONTINUED |
475 | * |
476 | * This is called when we might call do_notify_parent_cldstop(). |
477 | * |
478 | * @notify is zero if we would not ordinarily send a %SIGCHLD, |
479 | * or is the %CLD_STOPPED or %CLD_CONTINUED .si_code for %SIGCHLD. |
480 | * |
481 | * @why is %CLD_STOPPED when about to stop for job control; |
482 | * we are already in %TASK_STOPPED state, about to call schedule(). |
483 | * It might also be that we have just exited (check %PF_EXITING), |
484 | * but need to report that a group-wide stop is complete. |
485 | * |
486 | * @why is %CLD_CONTINUED when waking up after job control stop and |
487 | * ready to make a delayed @notify report. |
488 | * |
489 | * Return the %CLD_* value for %SIGCHLD, or zero to generate no signal. |
490 | * |
491 | * Called with the siglock held. |
492 | */ |
493 | static inline int tracehook_notify_jctl(int notify, int why) |
494 | { |
495 | return notify ?: (current->ptrace & PT_PTRACED) ? why : 0; |
496 | } |
497 | |
498 | /** |
499 | * tracehook_finish_jctl - report about return from job control stop |
500 | * |
501 | * This is called by do_signal_stop() after wakeup. |
502 | */ |
503 | static inline void tracehook_finish_jctl(void) |
504 | { |
505 | } |
506 | |
507 | #define DEATH_REAP -1 |
508 | #define DEATH_DELAYED_GROUP_LEADER -2 |
509 | |
510 | /** |
511 | * tracehook_notify_death - task is dead, ready to notify parent |
512 | * @task: @current task now exiting |
513 | * @death_cookie: value to pass to tracehook_report_death() |
514 | * @group_dead: nonzero if this was the last thread in the group to die |
515 | * |
516 | * A return value >= 0 means call do_notify_parent() with that signal |
517 | * number. Negative return value can be %DEATH_REAP to self-reap right |
518 | * now, or %DEATH_DELAYED_GROUP_LEADER to a zombie without notifying our |
519 | * parent. Note that a return value of 0 means a do_notify_parent() call |
520 | * that sends no signal, but still wakes up a parent blocked in wait*(). |
521 | * |
522 | * Called with write_lock_irq(&tasklist_lock) held. |
523 | */ |
524 | static inline int tracehook_notify_death(struct task_struct *task, |
525 | void **death_cookie, int group_dead) |
526 | { |
527 | if (task_detached(task)) |
528 | return task->ptrace ? SIGCHLD : DEATH_REAP; |
529 | |
530 | /* |
531 | * If something other than our normal parent is ptracing us, then |
532 | * send it a SIGCHLD instead of honoring exit_signal. exit_signal |
533 | * only has special meaning to our real parent. |
534 | */ |
535 | if (thread_group_empty(task) && !ptrace_reparented(task)) |
536 | return task->exit_signal; |
537 | |
538 | return task->ptrace ? SIGCHLD : DEATH_DELAYED_GROUP_LEADER; |
539 | } |
540 | |
541 | /** |
542 | * tracehook_report_death - task is dead and ready to be reaped |
543 | * @task: @current task now exiting |
544 | * @signal: return value from tracheook_notify_death() |
545 | * @death_cookie: value passed back from tracehook_notify_death() |
546 | * @group_dead: nonzero if this was the last thread in the group to die |
547 | * |
548 | * Thread has just become a zombie or is about to self-reap. If positive, |
549 | * @signal is the signal number just sent to the parent (usually %SIGCHLD). |
550 | * If @signal is %DEATH_REAP, this thread will self-reap. If @signal is |
551 | * %DEATH_DELAYED_GROUP_LEADER, this is a delayed_group_leader() zombie. |
552 | * The @death_cookie was passed back by tracehook_notify_death(). |
553 | * |
554 | * If normal reaping is not inhibited, @task->exit_state might be changing |
555 | * in parallel. |
556 | * |
557 | * Called without locks. |
558 | */ |
559 | static inline void tracehook_report_death(struct task_struct *task, |
560 | int signal, void *death_cookie, |
561 | int group_dead) |
562 | { |
563 | } |
564 | |
565 | #ifdef TIF_NOTIFY_RESUME |
566 | /** |
567 | * set_notify_resume - cause tracehook_notify_resume() to be called |
568 | * @task: task that will call tracehook_notify_resume() |
569 | * |
570 | * Calling this arranges that @task will call tracehook_notify_resume() |
571 | * before returning to user mode. If it's already running in user mode, |
572 | * it will enter the kernel and call tracehook_notify_resume() soon. |
573 | * If it's blocked, it will not be woken. |
574 | */ |
575 | static inline void set_notify_resume(struct task_struct *task) |
576 | { |
577 | if (!test_and_set_tsk_thread_flag(task, TIF_NOTIFY_RESUME)) |
578 | kick_process(task); |
579 | } |
580 | |
581 | /** |
582 | * tracehook_notify_resume - report when about to return to user mode |
583 | * @regs: user-mode registers of @current task |
584 | * |
585 | * This is called when %TIF_NOTIFY_RESUME has been set. Now we are |
586 | * about to return to user mode, and the user state in @regs can be |
587 | * inspected or adjusted. The caller in arch code has cleared |
588 | * %TIF_NOTIFY_RESUME before the call. If the flag gets set again |
589 | * asynchronously, this will be called again before we return to |
590 | * user mode. |
591 | * |
592 | * Called without locks. |
593 | */ |
594 | static inline void tracehook_notify_resume(struct pt_regs *regs) |
595 | { |
596 | } |
597 | #endif /* TIF_NOTIFY_RESUME */ |
598 | |
599 | #endif /* <linux/tracehook.h> */ |
600 |
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od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
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v3.9