| 0,0 → 1,507 |
|---|
| /* |
| * Copyright (c) 2008 Jiri Svoboda |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * - The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /** @addtogroup generic |
| * @{ |
| */ |
| |
| /** |
| * @file |
| * @brief Udebug operations. |
| * |
| * Udebug operations on tasks and threads are implemented here. The |
| * functions defined here are called from the udebug_ipc module |
| * when servicing udebug IPC messages. |
| */ |
| |
| #include <debug.h> |
| #include <proc/task.h> |
| #include <proc/thread.h> |
| #include <arch.h> |
| #include <errno.h> |
| #include <print.h> |
| #include <syscall/copy.h> |
| #include <ipc/ipc.h> |
| #include <udebug/udebug.h> |
| #include <udebug/udebug_ops.h> |
| |
| /** |
| * Prepare a thread for a debugging operation. |
| * |
| * Simply put, return thread t with t->udebug.lock held, |
| * but only if it verifies all conditions. |
| * |
| * Specifically, verifies that thread t exists, is a userspace thread, |
| * and belongs to the current task (TASK). Verifies, that the thread |
| * is (or is not) go according to being_go (typically false). |
| * It also locks t->udebug.lock, making sure that t->udebug.active |
| * is true - that the thread is in a valid debugging session. |
| * |
| * With this verified and the t->udebug.lock mutex held, it is ensured |
| * that the thread cannot leave the debugging session, let alone cease |
| * to exist. |
| * |
| * In this function, holding the TASK->udebug.lock mutex prevents the |
| * thread from leaving the debugging session, while relaxing from |
| * the t->lock spinlock to the t->udebug.lock mutex. |
| * |
| * @param t Pointer, need not at all be valid. |
| * @param being_go Required thread state. |
| * |
| * Returns EOK if all went well, or an error code otherwise. |
| */ |
| static int _thread_op_begin(thread_t *t, bool being_go) |
| { |
| task_id_t taskid; |
| ipl_t ipl; |
| |
| taskid = TASK->taskid; |
| |
| mutex_lock(&TASK->udebug.lock); |
| |
| /* thread_exists() must be called with threads_lock held */ |
| ipl = interrupts_disable(); |
| spinlock_lock(&threads_lock); |
| |
| if (!thread_exists(t)) { |
| spinlock_unlock(&threads_lock); |
| interrupts_restore(ipl); |
| mutex_unlock(&TASK->udebug.lock); |
| return ENOENT; |
| } |
| |
| /* t->lock is enough to ensure the thread's existence */ |
| spinlock_lock(&t->lock); |
| spinlock_unlock(&threads_lock); |
| |
| /* Verify that 't' is a userspace thread. */ |
| if ((t->flags & THREAD_FLAG_USPACE) == 0) { |
| /* It's not, deny its existence */ |
| spinlock_unlock(&t->lock); |
| interrupts_restore(ipl); |
| mutex_unlock(&TASK->udebug.lock); |
| return ENOENT; |
| } |
| |
| /* Verify debugging state. */ |
| if (t->udebug.active != true) { |
| /* Not in debugging session or undesired GO state */ |
| spinlock_unlock(&t->lock); |
| interrupts_restore(ipl); |
| mutex_unlock(&TASK->udebug.lock); |
| return ENOENT; |
| } |
| |
| /* |
| * Since the thread has active == true, TASK->udebug.lock |
| * is enough to ensure its existence and that active remains |
| * true. |
| */ |
| spinlock_unlock(&t->lock); |
| interrupts_restore(ipl); |
| |
| /* Only mutex TASK->udebug.lock left. */ |
| |
| /* Now verify that the thread belongs to the current task. */ |
| if (t->task != TASK) { |
| /* No such thread belonging this task*/ |
| mutex_unlock(&TASK->udebug.lock); |
| return ENOENT; |
| } |
| |
| /* |
| * Now we need to grab the thread's debug lock for synchronization |
| * of the threads stoppability/stop state. |
| */ |
| mutex_lock(&t->udebug.lock); |
| |
| /* The big task mutex is no longer needed. */ |
| mutex_unlock(&TASK->udebug.lock); |
| |
| if (t->udebug.go != being_go) { |
| /* Not in debugging session or undesired GO state. */ |
| mutex_unlock(&t->udebug.lock); |
| return EINVAL; |
| } |
| |
| /* Only t->udebug.lock left. */ |
| |
| return EOK; /* All went well. */ |
| } |
| |
| /** End debugging operation on a thread. */ |
| static void _thread_op_end(thread_t *t) |
| { |
| mutex_unlock(&t->udebug.lock); |
| } |
| |
| /** Begin debugging the current task. |
| * |
| * Initiates a debugging session for the current task (and its threads). |
| * When the debugging session has started a reply will be sent to the |
| * UDEBUG_BEGIN call. This may happen immediately in this function if |
| * all the threads in this task are stoppable at the moment and in this |
| * case the function returns 1. |
| * |
| * Otherwise the function returns 0 and the reply will be sent as soon as |
| * all the threads become stoppable (i.e. they can be considered stopped). |
| * |
| * @param call The BEGIN call we are servicing. |
| * @return 0 (OK, but not done yet), 1 (done) or negative error code. |
| */ |
| int udebug_begin(call_t *call) |
| { |
| int reply; |
| |
| thread_t *t; |
| link_t *cur; |
| |
| LOG("Debugging task %llu", TASK->taskid); |
| mutex_lock(&TASK->udebug.lock); |
| |
| if (TASK->udebug.dt_state != UDEBUG_TS_INACTIVE) { |
| mutex_unlock(&TASK->udebug.lock); |
| return EBUSY; |
| } |
| |
| TASK->udebug.dt_state = UDEBUG_TS_BEGINNING; |
| TASK->udebug.begin_call = call; |
| TASK->udebug.debugger = call->sender; |
| |
| if (TASK->udebug.not_stoppable_count == 0) { |
| TASK->udebug.dt_state = UDEBUG_TS_ACTIVE; |
| TASK->udebug.begin_call = NULL; |
| reply = 1; /* immediate reply */ |
| } else { |
| reply = 0; /* no reply */ |
| } |
| |
| /* Set udebug.active on all of the task's userspace threads. */ |
| |
| for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) { |
| t = list_get_instance(cur, thread_t, th_link); |
| |
| mutex_lock(&t->udebug.lock); |
| if ((t->flags & THREAD_FLAG_USPACE) != 0) |
| t->udebug.active = true; |
| mutex_unlock(&t->udebug.lock); |
| } |
| |
| mutex_unlock(&TASK->udebug.lock); |
| return reply; |
| } |
| |
| /** Finish debugging the current task. |
| * |
| * Closes the debugging session for the current task. |
| * @return Zero on success or negative error code. |
| */ |
| int udebug_end(void) |
| { |
| int rc; |
| |
| LOG("Task %" PRIu64, TASK->taskid); |
| |
| mutex_lock(&TASK->udebug.lock); |
| rc = udebug_task_cleanup(TASK); |
| mutex_unlock(&TASK->udebug.lock); |
| |
| return rc; |
| } |
| |
| /** Set the event mask. |
| * |
| * Sets the event mask that determines which events are enabled. |
| * |
| * @param mask Or combination of events that should be enabled. |
| * @return Zero on success or negative error code. |
| */ |
| int udebug_set_evmask(udebug_evmask_t mask) |
| { |
| LOG("mask = 0x%x", mask); |
| |
| mutex_lock(&TASK->udebug.lock); |
| |
| if (TASK->udebug.dt_state != UDEBUG_TS_ACTIVE) { |
| mutex_unlock(&TASK->udebug.lock); |
| return EINVAL; |
| } |
| |
| TASK->udebug.evmask = mask; |
| mutex_unlock(&TASK->udebug.lock); |
| |
| return 0; |
| } |
| |
| /** Give thread GO. |
| * |
| * Upon recieving a go message, the thread is given GO. Being GO |
| * means the thread is allowed to execute userspace code (until |
| * a debugging event or STOP occurs, at which point the thread loses GO. |
| * |
| * @param t The thread to operate on (unlocked and need not be valid). |
| * @param call The GO call that we are servicing. |
| */ |
| int udebug_go(thread_t *t, call_t *call) |
| { |
| int rc; |
| |
| /* On success, this will lock t->udebug.lock. */ |
| rc = _thread_op_begin(t, false); |
| if (rc != EOK) { |
| return rc; |
| } |
| |
| t->udebug.go_call = call; |
| t->udebug.go = true; |
| t->udebug.cur_event = 0; /* none */ |
| |
| /* |
| * Neither t's lock nor threads_lock may be held during wakeup. |
| */ |
| waitq_wakeup(&t->udebug.go_wq, WAKEUP_FIRST); |
| |
| _thread_op_end(t); |
| |
| return 0; |
| } |
| |
| /** Stop a thread (i.e. take its GO away) |
| * |
| * Generates a STOP event as soon as the thread becomes stoppable (i.e. |
| * can be considered stopped). |
| * |
| * @param t The thread to operate on (unlocked and need not be valid). |
| * @param call The GO call that we are servicing. |
| */ |
| int udebug_stop(thread_t *t, call_t *call) |
| { |
| int rc; |
| |
| LOG("udebug_stop()"); |
| |
| /* |
| * On success, this will lock t->udebug.lock. Note that this makes sure |
| * the thread is not stopped. |
| */ |
| rc = _thread_op_begin(t, true); |
| if (rc != EOK) { |
| return rc; |
| } |
| |
| /* Take GO away from the thread. */ |
| t->udebug.go = false; |
| |
| if (t->udebug.stoppable != true) { |
| /* Answer will be sent when the thread becomes stoppable. */ |
| _thread_op_end(t); |
| return 0; |
| } |
| |
| /* |
| * Answer GO call. |
| */ |
| |
| /* Make sure nobody takes this call away from us. */ |
| call = t->udebug.go_call; |
| t->udebug.go_call = NULL; |
| |
| IPC_SET_RETVAL(call->data, 0); |
| IPC_SET_ARG1(call->data, UDEBUG_EVENT_STOP); |
| |
| THREAD->udebug.cur_event = UDEBUG_EVENT_STOP; |
| |
| _thread_op_end(t); |
| |
| mutex_lock(&TASK->udebug.lock); |
| ipc_answer(&TASK->answerbox, call); |
| mutex_unlock(&TASK->udebug.lock); |
| |
| return 0; |
| } |
| |
| /** Read the list of userspace threads in the current task. |
| * |
| * The list takes the form of a sequence of thread hashes (i.e. the pointers |
| * to thread structures). A buffer of size @a buf_size is allocated and |
| * a pointer to it written to @a buffer. The sequence of hashes is written |
| * into this buffer. |
| * |
| * If the sequence is longer than @a buf_size bytes, only as much hashes |
| * as can fit are copied. The number of thread hashes copied is stored |
| * in @a n. |
| * |
| * The rationale for having @a buf_size is that this function is only |
| * used for servicing the THREAD_READ message, which always specifies |
| * a maximum size for the userspace buffer. |
| * |
| * @param buffer The buffer for storing thread hashes. |
| * @param buf_size Buffer size in bytes. |
| * @param n The actual number of hashes copied will be stored here. |
| */ |
| int udebug_thread_read(void **buffer, size_t buf_size, size_t *n) |
| { |
| thread_t *t; |
| link_t *cur; |
| unative_t tid; |
| unsigned copied_ids; |
| ipl_t ipl; |
| unative_t *id_buffer; |
| int flags; |
| size_t max_ids; |
| |
| LOG("udebug_thread_read()"); |
| |
| /* Allocate a buffer to hold thread IDs */ |
| id_buffer = malloc(buf_size, 0); |
| |
| mutex_lock(&TASK->udebug.lock); |
| |
| /* Verify task state */ |
| if (TASK->udebug.dt_state != UDEBUG_TS_ACTIVE) { |
| mutex_unlock(&TASK->udebug.lock); |
| return EINVAL; |
| } |
| |
| ipl = interrupts_disable(); |
| spinlock_lock(&TASK->lock); |
| /* Copy down the thread IDs */ |
| |
| max_ids = buf_size / sizeof(unative_t); |
| copied_ids = 0; |
| |
| /* FIXME: make sure the thread isn't past debug shutdown... */ |
| for (cur = TASK->th_head.next; cur != &TASK->th_head; cur = cur->next) { |
| /* Do not write past end of buffer */ |
| if (copied_ids >= max_ids) break; |
| |
| t = list_get_instance(cur, thread_t, th_link); |
| |
| spinlock_lock(&t->lock); |
| flags = t->flags; |
| spinlock_unlock(&t->lock); |
| |
| /* Not interested in kernel threads. */ |
| if ((flags & THREAD_FLAG_USPACE) != 0) { |
| /* Using thread struct pointer as identification hash */ |
| tid = (unative_t) t; |
| id_buffer[copied_ids++] = tid; |
| } |
| } |
| |
| spinlock_unlock(&TASK->lock); |
| interrupts_restore(ipl); |
| |
| mutex_unlock(&TASK->udebug.lock); |
| |
| *buffer = id_buffer; |
| *n = copied_ids * sizeof(unative_t); |
| |
| return 0; |
| } |
| |
| /** Read the arguments of a system call. |
| * |
| * The arguments of the system call being being executed are copied |
| * to an allocated buffer and a pointer to it is written to @a buffer. |
| * The size of the buffer is exactly such that it can hold the maximum number |
| * of system-call arguments. |
| * |
| * Unless the thread is currently blocked in a SYSCALL_B or SYSCALL_E event, |
| * this function will fail with an EINVAL error code. |
| * |
| * @param buffer The buffer for storing thread hashes. |
| */ |
| int udebug_args_read(thread_t *t, void **buffer) |
| { |
| int rc; |
| unative_t *arg_buffer; |
| |
| /* Prepare a buffer to hold the arguments. */ |
| arg_buffer = malloc(6 * sizeof(unative_t), 0); |
| |
| /* On success, this will lock t->udebug.lock. */ |
| rc = _thread_op_begin(t, false); |
| if (rc != EOK) { |
| return rc; |
| } |
| |
| /* Additionally we need to verify that we are inside a syscall. */ |
| if (t->udebug.cur_event != UDEBUG_EVENT_SYSCALL_B && |
| t->udebug.cur_event != UDEBUG_EVENT_SYSCALL_E) { |
| _thread_op_end(t); |
| return EINVAL; |
| } |
| |
| /* Copy to a local buffer before releasing the lock. */ |
| memcpy(arg_buffer, t->udebug.syscall_args, 6 * sizeof(unative_t)); |
| |
| _thread_op_end(t); |
| |
| *buffer = arg_buffer; |
| return 0; |
| } |
| |
| /** Read the memory of the debugged task. |
| * |
| * Reads @a n bytes from the address space of the debugged task, starting |
| * from @a uspace_addr. The bytes are copied into an allocated buffer |
| * and a pointer to it is written into @a buffer. |
| * |
| * @param uspace_addr Address from where to start reading. |
| * @param n Number of bytes to read. |
| * @param buffer For storing a pointer to the allocated buffer. |
| */ |
| int udebug_mem_read(unative_t uspace_addr, size_t n, void **buffer) |
| { |
| void *data_buffer; |
| int rc; |
| |
| /* Verify task state */ |
| mutex_lock(&TASK->udebug.lock); |
| |
| if (TASK->udebug.dt_state != UDEBUG_TS_ACTIVE) { |
| mutex_unlock(&TASK->udebug.lock); |
| return EBUSY; |
| } |
| |
| data_buffer = malloc(n, 0); |
| |
| /* NOTE: this is not strictly from a syscall... but that shouldn't |
| * be a problem */ |
| rc = copy_from_uspace(data_buffer, (void *)uspace_addr, n); |
| mutex_unlock(&TASK->udebug.lock); |
| |
| if (rc != 0) return rc; |
| |
| *buffer = data_buffer; |
| return 0; |
| } |
| |
| /** @} |
| */ |