source: trunk/kernel/syscalls/sys_thread_join.c @ 625

Last change on this file since 625 was 584, checked in by alain, 6 years ago

Introduce sys_place_fork() function.

File size: 6.2 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_busylock.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 : joining thread[%x,%x] enter / target thread[%x,%x] / cycle %d\n",
70__FUNCTION__ , process->pid, joining_ptr->trdid,
71process->pid, trdid, (uint32_t)tm_start );
72#endif
73
74    // check trdid argument
75        if( (target_ltid >= CONFIG_THREADS_MAX_PER_CLUSTER) || cluster_is_undefined(target_cxy) )
76        {
77
78#if DEBUG_SYSCALLS_ERROR
79printk("\n[ERROR] in %s : illegal trdid argument %x\n",
80__FUNCTION__, trdid );
81#endif
82                joining_ptr->errno = EINVAL;
83                return -1;
84        }
85
86    // check exit_value argument
87        if( exit_value != NULL )
88        {
89
90#if DEBUG_SYSCALLS_ERROR
91printk("\n[ERROR] in %s : exit_value argument must be NULL\n",
92__FUNCTION__ );
93#endif
94                joining_ptr->errno = EINVAL;
95                return -1;
96        }
97
98    // check target thread != this thread
99    if( joining_ptr->trdid == trdid )
100    {
101
102#if DEBUG_SYSCALLS_ERROR
103printk("\n[ERROR] in %s : this thread (%x) == target thread(%x)\n",
104__FUNCTION__, joining_ptr->trdid, trdid );
105#endif
106        joining_ptr->errno = EDEADLK;
107        return -1;
108    }
109
110    // get pointers on target thread
111        target_xp  = thread_get_xptr( process->pid , trdid );
112    target_ptr = GET_PTR( target_xp );
113
114    if( target_xp == XPTR_NULL )
115    {
116
117#if DEBUG_SYSCALLS_ERROR
118printk("\n[ERROR] in %s : target thread %x not found\n",
119__FUNCTION__, trdid );
120#endif
121        joining_ptr->errno = ESRCH;
122        return -1;
123    }
124
125    // get extended pointers on various fields in target thread
126    target_join_lock_xp = XPTR( target_cxy , &target_ptr->join_lock );
127    target_flags_xp     = XPTR( target_cxy , &target_ptr->flags );
128    target_blocked_xp   = XPTR( target_cxy , &target_ptr->blocked );
129    target_join_xp_xp   = XPTR( target_cxy , &target_ptr->join_xp );
130
131    // check target thread joinable
132    if( (hal_remote_l32( target_flags_xp ) & THREAD_FLAG_DETACHED) != 0 )
133    {
134
135#if DEBUG_SYSCALLS_ERROR
136printk("\n[ERROR] in %s : target thread %x not joinable\n", __FUNCTION__, trdid );
137#endif
138        joining_ptr->errno = EINVAL; 
139        return -1;
140    }
141
142    // mask IRQs
143    hal_disable_irq( &save_sr );
144
145    // get the lock protecting the join in target thread
146    remote_busylock_acquire( target_join_lock_xp );
147
148    // test the kill_done flag from the target thread
149    if( hal_remote_l32( target_flags_xp ) & THREAD_FLAG_KILL_DONE )  // killer thread is first
150    {
151        // get pointers on killer thread
152        killer_xp  = (xptr_t)hal_remote_l64( target_join_xp_xp );
153
154        // reset the kill_done flag in target thread
155        hal_remote_atomic_and( target_flags_xp , ~THREAD_FLAG_KILL_DONE );
156
157        // unblock the killer thread
158        thread_unblock( killer_xp , THREAD_BLOCKED_JOIN );
159
160        // release the lock protecting join     
161        remote_busylock_release( target_join_lock_xp );
162
163#if DEBUG_SYS_THREAD_JOIN
164tm_end = hal_get_cycles();
165if( DEBUG_SYS_THREAD_JOIN < tm_end )
166printk("\n[DBG] %s : joining thread[%x,%x] exit / target thread[%x,%x] completed / cycle %d\n",
167__FUNCTION__, process->pid, joining_ptr->trdid, process->pid, trdid, (uint32_t)tm_end );
168#endif
169
170    }
171    else                                                          // joining thread is first
172    {
173        // set the join_done flag in target thread
174        hal_remote_atomic_or( target_flags_xp , THREAD_FLAG_JOIN_DONE );
175
176        // block joining thread on BLOCKED_JOIN
177        thread_block( joining_xp , THREAD_BLOCKED_JOIN );
178
179        // register the joining thread extended pointer in target thread
180        hal_remote_s64( target_join_xp_xp , joining_xp );
181
182        // release the lock protecting the join     
183        remote_busylock_release( target_join_lock_xp );
184
185#if DEBUG_SYS_THREAD_JOIN
186if( DEBUG_SYS_THREAD_JOIN < tm_start )
187printk("\n[DBG] %s : joining thread[%x,%x] deschedules / target thread[%x,%x] not completed\n",
188__FUNCTION__ , process->pid, joining_ptr->trdid, process->pid, trdid );
189#endif
190        // deschedule
191        sched_yield( "joining thread waiting killer thread" );
192   
193#if DEBUG_SYS_THREAD_JOIN
194tm_end = hal_get_cycles();
195if( DEBUG_SYS_THREAD_JOIN < tm_end )
196printk("\n[DBG] %s : joining thread[%x,%x] exit / target thread[%x,%x] completed / cycle %d\n",
197__FUNCTION__ , process->pid, joining_ptr->trdid, process->pid, trdid, (uint32_t)tm_end );
198#endif
199
200    }
201
202    // restore IRQs
203    hal_restore_irq( save_sr );
204
205    return 0;
206
207}  // end sys_thread_join()
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