35,18 → 35,6 |
* @brief Udebug hooks and data structure management. |
* |
* Udebug is an interface that makes userspace debuggers possible. |
* |
* Functions in this file are executed directly in each thread, which |
* may or may not be the subject of debugging. The udebug_stoppable_begin/end() |
* functions are also executed in the clock interrupt handler. To avoid |
* deadlock, functions in this file are protected from the interrupt |
* by locking the recursive lock THREAD->udebug.int_lock (just an atomic |
* variable). This prevents udebug_stoppable_begin/end() from being |
* executed in the interrupt handler (they are skipped). |
* |
* Functions in udebug_ops.c and udebug_ipc.c execute in different threads, |
* so they needn't be protected from the (preemptible) interrupt-initiated |
* code. |
*/ |
|
#include <synch/waitq.h> |
55,16 → 43,7 |
#include <errno.h> |
#include <arch.h> |
|
static inline void udebug_int_lock(void) |
{ |
atomic_inc(&THREAD->udebug.int_lock); |
} |
|
static inline void udebug_int_unlock(void) |
{ |
atomic_dec(&THREAD->udebug.int_lock); |
} |
|
/** Initialize udebug part of task structure. |
* |
* Called as part of task structure initialization. |
89,12 → 68,8 |
mutex_initialize(&ut->lock, MUTEX_PASSIVE); |
waitq_initialize(&ut->go_wq); |
|
/* |
* At the beginning the thread is stoppable, so int_lock be set, too. |
*/ |
atomic_set(&ut->int_lock, 1); |
|
ut->go_call = NULL; |
ut->uspace_state = NULL; |
ut->go = false; |
ut->stoppable = true; |
ut->debug_active = false; |
161,11 → 136,8 |
ASSERT(THREAD); |
ASSERT(TASK); |
|
udebug_int_lock(); |
|
/* Early check for undebugged tasks */ |
if (!udebug_thread_precheck()) { |
udebug_int_unlock(); |
return; |
} |
|
231,7 → 203,6 |
{ |
/* Early check for undebugged tasks */ |
if (!udebug_thread_precheck()) { |
udebug_int_unlock(); |
return; |
} |
|
257,44 → 228,17 |
mutex_unlock(&THREAD->udebug.lock); |
mutex_unlock(&TASK->udebug.lock); |
} |
|
udebug_int_unlock(); |
} |
|
/** Upon being scheduled to run, check if the current thread should stop. |
* |
* This function is called from clock(). Preemption is enabled. |
* interrupts are disabled, but since this is called after |
* being scheduled-in, we can enable them, if we're careful enough |
* not to allow arbitrary recursion or deadlock with the thread context. |
* This function is called from clock(). |
*/ |
void udebug_before_thread_runs(void) |
{ |
ipl_t ipl; |
|
return; |
ASSERT(!PREEMPTION_DISABLED); |
|
/* |
* Prevent agains re-entering, such as when preempted inside this |
* function. |
*/ |
if (atomic_get(&THREAD->udebug.int_lock) != 0) |
return; |
|
udebug_int_lock(); |
|
ipl = interrupts_enable(); |
|
/* Now we're free to do whatever we need (lock mutexes, sleep, etc.) */ |
|
/* Check if we're supposed to stop */ |
udebug_stoppable_begin(); |
udebug_stoppable_end(); |
|
interrupts_restore(ipl); |
|
udebug_int_unlock(); |
} |
|
/** Syscall event hook. |
311,11 → 255,8 |
|
etype = end_variant ? UDEBUG_EVENT_SYSCALL_E : UDEBUG_EVENT_SYSCALL_B; |
|
udebug_int_lock(); |
|
/* Early check for undebugged tasks */ |
if (!udebug_thread_precheck()) { |
udebug_int_unlock(); |
return; |
} |
|
362,27 → 303,33 |
mutex_unlock(&TASK->udebug.lock); |
|
udebug_wait_for_go(&THREAD->udebug.go_wq); |
|
udebug_int_unlock(); |
} |
|
/** Thread-creation event hook. |
/** Thread-creation event hook combined with attaching the thread. |
* |
* Must be called when a new userspace thread is created in the debugged |
* task. Generates a THREAD_B event. |
* task. Generates a THREAD_B event. Also attaches the thread @a t |
* to the task @a ta. |
* |
* This is necessary to avoid a race condition where the BEGIN and THREAD_READ |
* requests would be handled inbetween attaching the thread and checking it |
* for being in a debugging session to send the THREAD_B event. We could then |
* either miss threads or get some threads both in the thread list |
* and get a THREAD_B event for them. |
* |
* @param t Structure of the thread being created. Not locked, as the |
* thread is not executing yet. |
* @param ta Task to which the thread should be attached. |
*/ |
void udebug_thread_b_event(struct thread *t) |
void udebug_thread_b_event_attach(struct thread *t, struct task *ta) |
{ |
call_t *call; |
|
udebug_int_lock(); |
|
mutex_lock(&TASK->udebug.lock); |
mutex_lock(&THREAD->udebug.lock); |
|
thread_attach(t, ta); |
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LOG("udebug_thread_b_event\n"); |
LOG("- check state\n"); |
|
419,8 → 366,6 |
|
LOG("- sleep\n"); |
udebug_wait_for_go(&THREAD->udebug.go_wq); |
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udebug_int_unlock(); |
} |
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/** Thread-termination event hook. |
432,8 → 377,6 |
{ |
call_t *call; |
|
udebug_int_lock(); |
|
mutex_lock(&TASK->udebug.lock); |
mutex_lock(&THREAD->udebug.lock); |
|
467,8 → 410,10 |
mutex_unlock(&THREAD->udebug.lock); |
mutex_unlock(&TASK->udebug.lock); |
|
/* Leave int_lock enabled. */ |
/* This event does not sleep - debugging has finished in this thread. */ |
/* |
* This event does not sleep - debugging has finished |
* in this thread. |
*/ |
} |
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/** |
491,8 → 436,6 |
LOG("udebug_task_cleanup()\n"); |
LOG("task %" PRIu64 "\n", ta->taskid); |
|
udebug_int_lock(); |
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if (ta->udebug.dt_state != UDEBUG_TS_BEGINNING && |
ta->udebug.dt_state != UDEBUG_TS_ACTIVE) { |
LOG("udebug_task_cleanup(): task not being debugged\n"); |
554,8 → 497,6 |
ta->udebug.dt_state = UDEBUG_TS_INACTIVE; |
ta->udebug.debugger = NULL; |
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udebug_int_unlock(); |
|
return 0; |
} |
|