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- /* Copyright (C) 2014 Stony Brook University
- This file is part of Graphene Library OS.
- Graphene Library OS is free software: you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public License
- as published by the Free Software Foundation, either version 3 of the
- License, or (at your option) any later version.
- Graphene Library OS is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- /*
- * db_threading.c
- *
- * This file contain APIs to create, exit and yield a thread.
- */
- #include "pal_defs.h"
- #include "pal_linux_defs.h"
- #include "pal.h"
- #include "pal_internal.h"
- #include "pal_linux.h"
- #include "pal_linux_error.h"
- #include "pal_error.h"
- #include "pal_debug.h"
- #include "api.h"
- #include "ecall_types.h"
- #include <linux/signal.h>
- #include <linux/mman.h>
- #include <linux/sched.h>
- #include <linux/types.h>
- #include <linux/wait.h>
- #include <list.h>
- static PAL_LOCK thread_list_lock = LOCK_INIT;
- DEFINE_LISTP(pal_handle_thread);
- static LISTP_TYPE(pal_handle_thread) thread_list = LISTP_INIT;
- struct thread_param {
- int (*callback) (void *);
- const void * param;
- };
- extern void * enclave_base;
- /*
- * We do not currently handle tid counter wrap-around, and could, in
- * principle, end up with two threads with the same ID. This is ok, as strict
- * uniqueness is not required; the tid is only used for debugging. We could
- * ensure uniqueness if needed in the future
- */
- static PAL_IDX pal_assign_tid(void)
- {
- static struct atomic_int tid = ATOMIC_INIT(0);
- return _atomic_add(1, &tid);
- }
- void pal_start_thread (void)
- {
- struct pal_handle_thread *new_thread = NULL, *tmp;
- _DkInternalLock(&thread_list_lock);
- LISTP_FOR_EACH_ENTRY(tmp, &thread_list, list)
- if (!tmp->tcs) {
- new_thread = tmp;
- new_thread->tid = pal_assign_tid();
- new_thread->tcs =
- enclave_base + GET_ENCLAVE_TLS(tcs_offset);
- break;
- }
- _DkInternalUnlock(&thread_list_lock);
- if (!new_thread)
- return;
- struct thread_param * thread_param =
- (struct thread_param *) new_thread->param;
- int (*callback) (void *) = thread_param->callback;
- const void * param = thread_param->param;
- free(thread_param);
- new_thread->param = NULL;
- SET_ENCLAVE_TLS(thread, new_thread);
- SET_ENCLAVE_TLS(ready_for_exceptions, 1UL);
- PAL_TCB* pal_tcb = pal_get_tcb();
- memset(&pal_tcb->libos_tcb, 0, sizeof(pal_tcb->libos_tcb));
- callback((void *) param);
- _DkThreadExit(/*clear_child_tid=*/NULL);
- }
- /* _DkThreadCreate for internal use. Create an internal thread
- inside the current process. The arguments callback and param
- specify the starting function and parameters */
- int _DkThreadCreate (PAL_HANDLE * handle, int (*callback) (void *),
- const void * param)
- {
- PAL_HANDLE new_thread = malloc(HANDLE_SIZE(thread));
- SET_HANDLE_TYPE(new_thread, thread);
- /*
- * tid will be filled later by pal_start_thread()
- * tid is cleared to avoid random value here.
- */
- new_thread->thread.tid = 0;
- new_thread->thread.tcs = NULL;
- INIT_LIST_HEAD(&new_thread->thread, list);
- struct thread_param * thread_param = malloc(sizeof(struct thread_param));
- thread_param->callback = callback;
- thread_param->param = param;
- new_thread->thread.param = (void *) thread_param;
- _DkInternalLock(&thread_list_lock);
- LISTP_ADD_TAIL(&new_thread->thread, &thread_list, list);
- _DkInternalUnlock(&thread_list_lock);
- int ret = ocall_clone_thread();
- if (IS_ERR(ret))
- return unix_to_pal_error(ERRNO(ret));
- *handle = new_thread;
- return 0;
- }
- int _DkThreadDelayExecution (unsigned long * duration)
- {
- int ret = ocall_sleep(duration);
- return IS_ERR(ret) ? unix_to_pal_error(ERRNO(ret)) : ret;
- }
- /* PAL call DkThreadYieldExecution. Yield the execution
- of the current thread. */
- void _DkThreadYieldExecution (void)
- {
- ocall_sleep(NULL);
- }
- /* _DkThreadExit for internal use: Thread exiting */
- noreturn void _DkThreadExit(int* clear_child_tid) {
- struct pal_handle_thread* exiting_thread = GET_ENCLAVE_TLS(thread);
- /* thread is ready to exit, must inform LibOS by erasing clear_child_tid;
- * note that we don't do it now (because this thread still occupies SGX
- * TCS slot) but during handle_thread_reset in assembly code */
- SET_ENCLAVE_TLS(clear_child_tid, clear_child_tid);
- static_assert(sizeof(*clear_child_tid) == 4, "unexpected clear_child_tid size");
- /* main thread is not part of the thread_list */
- if(exiting_thread != &pal_control.first_thread->thread) {
- _DkInternalLock(&thread_list_lock);
- LISTP_DEL(exiting_thread, &thread_list, list);
- _DkInternalUnlock(&thread_list_lock);
- }
- ocall_exit(0, /*is_exitgroup=*/false);
- }
- int _DkThreadResume (PAL_HANDLE threadHandle)
- {
- int ret = ocall_resume_thread(threadHandle->thread.tcs);
- return IS_ERR(ret) ? unix_to_pal_error(ERRNO(ret)) : ret;
- }
- struct handle_ops thread_ops = {
- /* nothing */
- };
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