source: trunk/kernel/syscalls/sys_thread_join.c @ 506

Last change on this file since 506 was 506, checked in by viala@…, 3 years ago

[syscalls] add interface in implementation.

Add const where possible, fix protoypes to follow interface.

File size: 5.8 KB
Line 
1/*
2 * sys_thread_join.c - passive wait on the end of a given thread.
3 *
4 * Authors    Alain Greiner (2016,2017)
5 *
6 * Copyright (c) 2011,2012 UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-MKH; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#include <hal_kernel_types.h>
25#include <hal_remote.h>
26#include <hal_special.h>
27#include <hal_irqmask.h>
28#include <thread.h>
29#include <vmm.h>
30#include <scheduler.h>
31#include <errno.h>
32#include <printk.h>
33#include <remote_spinlock.h>
34
35#include <syscalls.h>
36
37///////////////////////////////////////
38int sys_thread_join ( trdid_t    trdid,
39                      void    ** exit_value )
40{
41    reg_t         save_sr;
42    xptr_t        target_xp;
43    thread_t    * target_ptr;
44    cxy_t         target_cxy;
45    ltid_t        target_ltid;
46    xptr_t        target_join_lock_xp;
47    xptr_t        target_flags_xp;
48    xptr_t        target_blocked_xp;
49    xptr_t        target_join_xp_xp;
50    xptr_t        killer_xp;
51    xptr_t        joining_xp;
52    thread_t    * joining_ptr;
53    process_t   * process;
54
55    // get joining thread pointers
56        joining_ptr = CURRENT_THREAD;
57    joining_xp  = XPTR( local_cxy , joining_ptr );
58    process     = joining_ptr->process;
59
60    // get target thread ltid and cxy
61    target_ltid = LTID_FROM_TRDID( trdid );
62    target_cxy  = CXY_FROM_TRDID( trdid );
63
64#if DEBUG_SYS_THREAD_JOIN
65uint64_t     tm_start;
66uint64_t     tm_end;
67tm_start = hal_get_cycles();
68if( DEBUG_SYS_THREAD_JOIN < tm_start )
69printk("\n[DBG] %s : parent thread %x enter / process %x / target trdid %x / cycle %d\n",
70__FUNCTION__ , joining_ptr , process->pid , trdid , (uint32_t)tm_start );
71#endif
72
73    // check trdid argument
74        if( (target_ltid >= CONFIG_THREAD_MAX_PER_CLUSTER) || cluster_is_undefined( target_cxy ) ) 
75        {
76
77#if DEBUG_SYSCALLS_ERROR
78printk("\n[ERROR] in %s : illegal trdid argument %x\n", __FUNCTION__, trdid );
79#endif
80                joining_ptr->errno = EINVAL;
81                return -1;
82        }
83
84    // check exit_value argument
85        if( exit_value != NULL )
86        {
87
88#if DEBUG_SYSCALLS_ERROR
89printk("\n[ERROR] in %s : exit_value argument must be NULL\n", __FUNCTION__ );
90#endif
91                joining_ptr->errno = EINVAL;
92                return -1;
93        }
94
95    // check target thread != this thread
96    if( joining_ptr->trdid == trdid )
97    {
98
99#if DEBUG_SYSCALLS_ERROR
100printk("\n[ERROR] in %s : this thread (%x) == target thread(%x)\n",
101__FUNCTION__, joining_ptr->trdid, trdid );
102#endif
103        joining_ptr->errno = EDEADLK;
104        return -1;
105    }
106
107    // get pointers on target thread
108        target_xp  = thread_get_xptr( process->pid , trdid );
109    target_ptr = GET_PTR( target_xp );
110
111    if( target_xp == XPTR_NULL )
112    {
113
114#if DEBUG_SYSCALLS_ERROR
115printk("\n[ERROR] in %s : target thread %x not found\n", __FUNCTION__, trdid );
116#endif
117        joining_ptr->errno = ESRCH;
118        return -1;
119    }
120
121    // get extended pointers on various fields in target thread
122    target_join_lock_xp = XPTR( target_cxy , &target_ptr->join_lock );
123    target_flags_xp     = XPTR( target_cxy , &target_ptr->flags );
124    target_blocked_xp   = XPTR( target_cxy , &target_ptr->blocked );
125    target_join_xp_xp   = XPTR( target_cxy , &target_ptr->join_xp );
126
127    // check target thread joinable
128    if( (hal_remote_lw( target_flags_xp ) & THREAD_FLAG_DETACHED) == 0 )
129    {
130
131#if DEBUG_SYSCALLS_ERROR
132printk("\n[ERROR] in %s : target thread %x not joinable\n", __FUNCTION__, trdid );
133#endif
134        joining_ptr->errno = EINVAL; 
135        return -1;
136    }
137
138    // mask IRQs
139    hal_disable_irq( &save_sr );
140
141    // get the lock protecting the join in target thread
142    remote_spinlock_lock( target_join_lock_xp );
143
144    // test the kill_done flag from the target thread
145    if( hal_remote_lw( target_flags_xp ) & THREAD_FLAG_KILL_DONE )  // killer thread is first
146    {
147        // get pointers on killer thread
148        killer_xp  = (xptr_t)hal_remote_lwd( target_join_xp_xp );
149
150        // reset the kill_done flag in target thread
151        hal_remote_atomic_and( target_flags_xp , ~THREAD_FLAG_KILL_DONE );
152
153        // unblock the killer thread
154        thread_unblock( killer_xp , THREAD_BLOCKED_JOIN );
155
156        // release the lock protecting join     
157        remote_spinlock_unlock( target_join_lock_xp );
158
159        // restore IRQs
160        hal_restore_irq( save_sr );
161    }
162    else                                                          // joining thread is first
163    {
164        // set the join_done flag in target thread
165        hal_remote_atomic_or( target_flags_xp , THREAD_FLAG_JOIN_DONE );
166
167        // block joining thread on BLOCKED_JOIN
168        thread_block( joining_xp , THREAD_BLOCKED_JOIN );
169
170        // register the joining thread extended pointer in target thread
171        hal_remote_swd( target_join_xp_xp , joining_xp );
172
173        // release the lock protecting the join     
174        remote_spinlock_unlock( target_join_lock_xp );
175
176        // deschedule
177        sched_yield( "joining thread waiting killer thread" );
178   
179        // restore IRQs
180        hal_restore_irq( save_sr );
181    }
182
183#if DEBUG_SYS_THREAD_JOIN
184tm_end = hal_get_cycles();
185if( DEBUG_SYS_THREAD_JOIN < tm_end )
186printk("\n[DBG] %s : parent thread %x exit / process %x / target trdid %x / cycle %d\n",
187__FUNCTION__, joining_ptr, process->pid, trdid, (uint32_t)tm_end );
188#endif
189
190    return 0;
191
192}  // end sys_thread_join()
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