/* * remote_sem.c - Kernel function implementing the semaphore related syscalls. * * Author Alain Greiner (2016) * * Copyright (c) UPMC Sorbonne Universites * * This file is part of ALMOS-MKH. * * ALMOS-MKH is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2.0 of the License. * * ALMOS-MKH 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 * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ALMOS-MKH; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include #include #include #include #include #include /////////////////////////////////////////////// xptr_t remote_sem_from_vaddr( intptr_t vaddr ) { // get pointer on local process_descriptor process_t * process = CURRENT_PROCESS; // get extended pointer on reference process xptr_t ref_xp = process->ref_xp; // get cluster and local pointer on reference process cxy_t ref_cxy = GET_CXY( ref_xp ); process_t * ref_ptr = (process_t *)GET_PTR( ref_xp ); // get extended pointer on root of semaphores list xptr_t root_xp = XPTR( ref_cxy , &ref_ptr->sem_root ); // scan reference process semaphores list xptr_t iter_xp; xptr_t sem_xp; cxy_t sem_cxy; remote_sem_t * sem_ptr; intptr_t ident; bool_t found = false; XLIST_FOREACH( root_xp , iter_xp ) { sem_xp = XLIST_ELEMENT( iter_xp , remote_sem_t , sem_list ); sem_cxy = GET_CXY( sem_xp ); sem_ptr = (remote_sem_t *)GET_PTR( sem_xp ); ident = hal_remote_lw( XPTR( sem_cxy , &sem_ptr->ident ) ); if( ident == vaddr ) { found = true; break; } } if( found == false ) return XPTR_NULL; else return sem_xp; } // end remote_sem_from_vaddr() ///////////////////////////////////////// error_t remote_sem_init( intptr_t vaddr, uint32_t value ) { xptr_t sem_xp; remote_sem_t * sem_ptr; // get pointer on local process descriptor process_t * process = CURRENT_PROCESS; // get extended pointer on reference process xptr_t ref_xp = process->ref_xp; cxy_t ref_cxy = GET_CXY( ref_xp ); process_t * ref_ptr = (process_t *)GET_PTR( ref_xp ); // allocate memory for new semaphore in reference cluster if( ref_cxy == local_cxy ) // local cluster is the reference { kmem_req_t req; req.type = KMEM_SEM; req.flags = AF_ZERO; sem_ptr = kmem_alloc( &req ); sem_xp = XPTR( local_cxy , sem_ptr ); } else // reference is remote { rpc_semaphore_alloc_client( ref_cxy , &sem_xp ); sem_ptr = (remote_sem_t *)GET_PTR( sem_xp ); } if( sem_xp == XPTR_NULL ) return ENOMEM; // initialise semaphore lock remote_spinlock_init( XPTR( ref_cxy , &sem_ptr->lock ) ); // initialise semaphore count hal_remote_sw( XPTR( ref_cxy , &sem_ptr->count ) , value ); // initialise vaddr hal_remote_spt( XPTR( ref_cxy , &sem_ptr->ident ) , (void *)vaddr ); // initialise waiting threads queue xlist_root_init( XPTR( ref_cxy , &sem_ptr->wait_queue ) ); // register new semaphore in reference process xlist xptr_t root_xp = XPTR( ref_cxy , &ref_ptr->sem_root ); xptr_t xp_list = XPTR( ref_cxy , &sem_ptr->sem_list ); xlist_add_first( root_xp , xp_list ); return 0; } // en remote_sem_init() ////////////////////////////////// void remote_sem_wait( xptr_t sem_xp ) { // get semaphore cluster and local pointer cxy_t sem_cxy = GET_CXY( sem_xp ); remote_sem_t * sem_ptr = (remote_sem_t *)GET_PTR( sem_xp ); // get lock protecting semaphore remote_spinlock_lock( XPTR( sem_cxy , &sem_ptr->lock ) ); // get semaphore current value uint32_t count = hal_remote_lw( XPTR( sem_cxy , &sem_ptr->count ) ); if( count > 0 ) // success { // decrement semaphore value hal_remote_sw( XPTR( sem_cxy , &sem_ptr->count ) , count - 1 ); // release lock remote_spinlock_unlock( XPTR( sem_cxy , &sem_ptr->lock ) ); } else // failure { thread_t * this = CURRENT_THREAD; // register thread in waiting queue xptr_t root_xp = (xptr_t)hal_remote_lwd( XPTR( sem_cxy , &sem_ptr->wait_queue ) ); xptr_t thread_xp = XPTR( local_cxy , this ); xlist_add_last( root_xp , thread_xp ); // release lock remote_spinlock_unlock( XPTR( sem_cxy , &sem_ptr->lock ) ); // block and deschedule thread_block( this , THREAD_BLOCKED_SEM ); sched_yield(); } } // end remote_sem_wait() ///////////////////////////////////// void remote_sem_post( xptr_t sem_xp ) { // get semaphore cluster and local pointer cxy_t sem_cxy = GET_CXY( sem_xp ); remote_sem_t * sem_ptr = (remote_sem_t *)GET_PTR( sem_xp ); // get lock protecting semaphore remote_spinlock_lock( XPTR( sem_cxy , &sem_ptr->lock ) ); // get remote pointer on waiting queue root xptr_t queue_xp = (xptr_t)hal_remote_lwd( XPTR( sem_cxy , &sem_ptr->wait_queue ) ); if( xlist_is_empty( queue_xp ) ) // no waiting thread { // get semaphore current value uint32_t count = hal_remote_lw( XPTR( sem_cxy , &sem_ptr->count ) ); // increment semaphore value hal_remote_sw( XPTR( sem_cxy , &sem_ptr->count ) , count + 1 ); } else { // get first waiting thread from queue xptr_t thread_xp = XLIST_FIRST_ELEMENT( queue_xp , thread_t , wait_list ); // get thread cluster and local poiner cxy_t thread_cxy = GET_CXY( thread_xp ); thread_t * thread_ptr = (thread_t *)GET_PTR( thread_xp ); // remove the thread from the waiting queue, and unblock xlist_unlink( XPTR( thread_cxy , &thread_ptr->wait_list ) ); thread_unblock( thread_xp , THREAD_BLOCKED_SEM ); } // release lock remote_spinlock_unlock( XPTR( sem_cxy , &sem_ptr->lock ) ); } // end remote_sem_post() //////////////////////////////////////// void remote_sem_destroy( xptr_t sem_xp ) { // get semaphore cluster and local pointer cxy_t sem_cxy = GET_CXY( sem_xp ); remote_sem_t * sem_ptr = (remote_sem_t *)GET_PTR( sem_xp ); // get lock protecting semaphore remote_spinlock_lock( XPTR( sem_cxy , &sem_ptr->lock ) ); // get remote pointer on waiting queue xptr_t queue_xp = (xptr_t)hal_remote_lwd( XPTR( sem_cxy , &sem_ptr->wait_queue ) ); if( !xlist_is_empty( queue_xp ) ) // user error { printk("WARNING in %s for thread %x in process %x : " "destroy semaphore, but waiting threads queue not empty\n", __FUNCTION__ , CURRENT_THREAD->trdid , CURRENT_PROCESS->pid ); } // reset semaphore count hal_remote_sw( XPTR( sem_cxy , &sem_ptr->count ) , 0 ); // remove semaphore from process xptr_t xp_list = (xptr_t)hal_remote_lwd( XPTR( sem_cxy , &sem_ptr->sem_list ) ); xlist_unlink( xp_list ); // release lock remote_spinlock_unlock( XPTR( sem_cxy , &sem_ptr->lock ) ); // release memory allocated if( sem_cxy == local_cxy ) // reference is local { kmem_req_t req; req.type = KMEM_SEM; req.ptr = sem_ptr; kmem_free( &req ); } else // reference is remote { rpc_semaphore_free_client( sem_cxy , sem_ptr ); } } // end remote_sem_destroy() ////////////////////////////////////////////// void remote_sem_get_value( xptr_t sem_xp, uint32_t * data ) { // get semaphore cluster and local pointer cxy_t sem_cxy = GET_CXY( sem_xp ); remote_sem_t * sem_ptr = (remote_sem_t *)GET_PTR( sem_xp ); *data = hal_remote_lw( XPTR( sem_cxy , &sem_ptr->count ) ); } // end remote_sem_get_value()