1 | /* |
---|
2 | * sys_fork.c - Fork the current process. |
---|
3 | * |
---|
4 | * Authors Alain Greiner (2016,2017) |
---|
5 | * |
---|
6 | * Copyright (c) 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 <kernel_config.h> |
---|
25 | #include <hal_types.h> |
---|
26 | #include <hal_context.h> |
---|
27 | #include <hal_switch.h> |
---|
28 | #include <hal_atomic.h> |
---|
29 | #include <errno.h> |
---|
30 | #include <printk.h> |
---|
31 | #include <core.h> |
---|
32 | #include <cluster.h> |
---|
33 | #include <list.h> |
---|
34 | #include <thread.h> |
---|
35 | #include <scheduler.h> |
---|
36 | #include <kmem.h> |
---|
37 | #include <dqdt.h> |
---|
38 | #include <process.h> |
---|
39 | |
---|
40 | ////////////// |
---|
41 | int sys_fork() |
---|
42 | { |
---|
43 | process_t * parent_process; // pointer on parent process descriptor |
---|
44 | pid_t parent_pid; // parent process identifier |
---|
45 | thread_t * parent_thread; // pointer on parent thread descriptor |
---|
46 | process_t * child_process; // pointer on child process descriptor |
---|
47 | pid_t child_pid; // child process identifier |
---|
48 | thread_t * child_thread; // pointer on child main thread descriptor |
---|
49 | cxy_t target_cxy; // target cluster for forked child process |
---|
50 | error_t error; |
---|
51 | |
---|
52 | uint64_t tm_start; |
---|
53 | uint64_t tm_end; |
---|
54 | |
---|
55 | tm_start = hal_get_cycles(); |
---|
56 | |
---|
57 | // get pointers on parent process and thread |
---|
58 | parent_thread = CURRENT_THREAD; |
---|
59 | parent_process = parent_thread->process; |
---|
60 | parent_pid = parent_process->pid; |
---|
61 | |
---|
62 | fork_dmsg("\n[DBG] %s : core[%x,%d] enters for process %x / cycle %d\n", |
---|
63 | __FUNCTION__ , local_cxy , parent_thread->core->lid , parent_pid , (uint32_t)tm_start ); |
---|
64 | |
---|
65 | // check parent process children number |
---|
66 | if( hal_atomic_add( &parent_process->children_nr , 1 ) >= CONFIG_PROCESS_MAX_CHILDREN ) |
---|
67 | { |
---|
68 | printk("\n[ERROR] in %s : too much children processes\n", __FUNCTION__); |
---|
69 | hal_atomic_add ( &parent_process->children_nr , -1 ); |
---|
70 | return EAGAIN; |
---|
71 | } |
---|
72 | |
---|
73 | // Select target cluster for future migration of child process and main thread. |
---|
74 | // If placement is not user-defined, the placement is defined by the DQDT. |
---|
75 | // The two first processes ("init" and "sh") on boot cluster do not migrate. |
---|
76 | |
---|
77 | if( parent_thread->fork_user ) |
---|
78 | { |
---|
79 | // user defined placement |
---|
80 | target_cxy = parent_thread->fork_cxy; |
---|
81 | parent_thread->fork_user = false; |
---|
82 | } |
---|
83 | else if( (LPID_FROM_PID(parent_process->pid) < 2) && (local_cxy == 0) ) |
---|
84 | { |
---|
85 | // 2 first process stay in boot cluster |
---|
86 | target_cxy = local_cxy; |
---|
87 | } |
---|
88 | else |
---|
89 | { |
---|
90 | // DQDT placement |
---|
91 | target_cxy = dqdt_get_cluster_for_process(); |
---|
92 | } |
---|
93 | |
---|
94 | //printk("\n[DBG] %s : core[%x,%d] for process %x selects target_cluster = %x\n", |
---|
95 | //__FUNCTION__ , local_cxy , parent_thread->core->lid , parent_pid , target_cxy ); |
---|
96 | |
---|
97 | // allocates memory in local cluster for the child process descriptor |
---|
98 | child_process = process_alloc(); |
---|
99 | |
---|
100 | if( child_process == NULL ) |
---|
101 | { |
---|
102 | printk("\n[ERROR] in %s : cannot allocate child process\n", __FUNCTION__ ); |
---|
103 | hal_atomic_add ( &parent_process->children_nr , -1 ); |
---|
104 | return EAGAIN; |
---|
105 | } |
---|
106 | |
---|
107 | // get a new PID for child process, |
---|
108 | if( target_cxy == local_cxy ) // target cluster is local |
---|
109 | { |
---|
110 | error = cluster_pid_alloc( XPTR( target_cxy , child_process ) , &child_pid ); |
---|
111 | } |
---|
112 | else // target cluster is remote |
---|
113 | { |
---|
114 | rpc_process_pid_alloc_client( target_cxy , child_process , &error , &child_pid ); |
---|
115 | } |
---|
116 | |
---|
117 | if( error ) |
---|
118 | { |
---|
119 | printk("\n[ERROR] in %s : cannot allocate PID\n", __FUNCTION__ ); |
---|
120 | hal_atomic_add ( &parent_process->children_nr , -1 ); |
---|
121 | process_destroy( child_process ); |
---|
122 | return EAGAIN; |
---|
123 | } |
---|
124 | |
---|
125 | // initialize and register the child process descriptor |
---|
126 | process_reference_init( child_process , child_pid , XPTR(local_cxy, parent_process) ); |
---|
127 | |
---|
128 | // initialises child process standard files structures |
---|
129 | // ( root / cwd / bin ) from parent process descriptor |
---|
130 | |
---|
131 | vfs_file_count_up( parent_process->vfs_root_xp ); |
---|
132 | child_process->vfs_root_xp = parent_process->vfs_root_xp; |
---|
133 | |
---|
134 | vfs_file_count_up( parent_process->vfs_cwd_xp ); |
---|
135 | child_process->vfs_cwd_xp = parent_process->vfs_cwd_xp; |
---|
136 | |
---|
137 | vfs_file_count_up( parent_process->vfs_bin_xp ); |
---|
138 | child_process->vfs_bin_xp = parent_process->vfs_bin_xp; |
---|
139 | |
---|
140 | // copy the parent process fd_array to the child process fd_array |
---|
141 | process_fd_remote_copy( XPTR( local_cxy , &child_process->fd_array ), |
---|
142 | XPTR( local_cxy , &parent_process->fd_array ) ); |
---|
143 | |
---|
144 | //printk("\n[DBG] %s : core[%x,%d] for process %x created child process %x\n", |
---|
145 | //__FUNCTION__ , local_cxy , parent_thread->core->lid , parent_pid , child_pid ); |
---|
146 | |
---|
147 | // replicate VMM |
---|
148 | error = vmm_copy( child_process , parent_process ); |
---|
149 | |
---|
150 | if( error ) |
---|
151 | { |
---|
152 | printk("\n[ERROR] in %s : cannot duplicate VMM\n", __FUNCTION__ ); |
---|
153 | hal_atomic_add ( &parent_process->children_nr , -1 ); |
---|
154 | process_destroy( child_process ); |
---|
155 | return ENOMEM; |
---|
156 | } |
---|
157 | |
---|
158 | //printk("\n[DBG] %s : core[%x,%d] for process %x duplicated vmm in child process\n", |
---|
159 | //__FUNCTION__ , local_cxy , parent_thread->core->lid , parent_pid ); |
---|
160 | //vmm_display( parent_process , true ); |
---|
161 | //vmm_display( child_process , true ); |
---|
162 | |
---|
163 | // create child main thread in local cluster |
---|
164 | error = thread_user_fork( child_process, |
---|
165 | parent_thread->u_stack_size, |
---|
166 | parent_thread->u_stack_base, |
---|
167 | &child_thread ); |
---|
168 | if( error ) |
---|
169 | { |
---|
170 | printk("\n[ERROR] in %s : cannot duplicate main thread\n", __FUNCTION__ ); |
---|
171 | hal_atomic_add( &parent_process->children_nr , -1 ); |
---|
172 | process_destroy( child_process ); |
---|
173 | return ENOMEM; |
---|
174 | } |
---|
175 | |
---|
176 | //printk("\n[DBG] %s : core[%x,%d] initialised child main thread\n", |
---|
177 | //__FUNCTION__ , local_cxy , parent_thread->core->lid ); |
---|
178 | |
---|
179 | // update DQDT for the child thread |
---|
180 | dqdt_local_update_threads( 1 ); |
---|
181 | |
---|
182 | // set child_thread FPU_context from parent_thread register values |
---|
183 | // only when the parent process is the FPU owner |
---|
184 | if( CURRENT_THREAD->core->fpu_owner == parent_thread ) |
---|
185 | { |
---|
186 | hal_fpu_context_save( child_thread->fpu_context ); |
---|
187 | } |
---|
188 | |
---|
189 | // set child_thread CPU context from parent_thread register values |
---|
190 | hal_do_cpu_save( child_thread->cpu_context, |
---|
191 | child_thread, |
---|
192 | (int)((intptr_t)child_thread - (intptr_t)parent_thread) ); |
---|
193 | |
---|
194 | |
---|
195 | // from this point, both parent and child threads execute the following code |
---|
196 | // but child execute it only when it has been unblocked by its parent |
---|
197 | |
---|
198 | thread_t * current = CURRENT_THREAD; |
---|
199 | |
---|
200 | if( current == parent_thread ) |
---|
201 | { |
---|
202 | // parent_thread unblock child_thread |
---|
203 | thread_unblock( XPTR( local_cxy , child_thread ) , THREAD_BLOCKED_GLOBAL ); |
---|
204 | |
---|
205 | tm_end = hal_get_cycles(); |
---|
206 | |
---|
207 | fork_dmsg("\n[DBG] %s : core[%x,%d] parent_process %x exit / cycle %d\n" |
---|
208 | " child_process %x / child_thread = %x / cost = %d\n", |
---|
209 | __FUNCTION__, local_cxy, parent_thread->core->lid, parent_pid, (uint32_t)tm_start, |
---|
210 | child_pid, child_thread->trdid , (uint32_t)(tm_end - tm_start) ); |
---|
211 | |
---|
212 | return child_pid; |
---|
213 | } |
---|
214 | else // current == child_thread |
---|
215 | { |
---|
216 | assert( (current == child_thread) , __FUNCTION__ , |
---|
217 | "current thread %x is not the child thread %x\n", current , child_thread ); |
---|
218 | |
---|
219 | fork_dmsg("\n[DBG] %s : core[%x,%d] child process %x exit / cycle %d\n", |
---|
220 | __FUNCTION__, local_cxy, parent_thread->core->lid, child_pid, (uint32_t)hal_get_cycles() ); |
---|
221 | |
---|
222 | return 0; |
---|
223 | } |
---|
224 | |
---|
225 | } // end sys_fork() |
---|
226 | |
---|