/* 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 . */
/*
* 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
#include
#include
#include
#include
#include
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 */
};