1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
|
/**
* @file
*
* @brief Dispatch Thread
* @ingroup ScoreThread
*/
/*
* COPYRIGHT (c) 1989-2009.
* On-Line Applications Research Corporation (OAR).
*
* Copyright (c) 2014, 2016 embedded brains GmbH.
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.org/license/LICENSE.
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <rtems/score/threaddispatch.h>
#include <rtems/score/assert.h>
#include <rtems/score/isr.h>
#include <rtems/score/schedulerimpl.h>
#include <rtems/score/threadimpl.h>
#include <rtems/score/todimpl.h>
#include <rtems/score/userextimpl.h>
#include <rtems/score/wkspace.h>
#include <rtems/config.h>
#if __RTEMS_ADA__
void *rtems_ada_self;
#endif
#if ( CPU_HARDWARE_FP == TRUE ) || ( CPU_SOFTWARE_FP == TRUE )
Thread_Control *_Thread_Allocated_fp;
#endif
CHAIN_DEFINE_EMPTY( _User_extensions_Switches_list );
#if defined(RTEMS_SMP)
static bool _Thread_Can_ask_for_help( const Thread_Control *executing )
{
return executing->Scheduler.helping_nodes > 0
&& _Thread_Is_ready( executing );
}
#endif
static void _Thread_Preemption_intervention( Per_CPU_Control *cpu_self )
{
#if defined(RTEMS_SMP)
_Per_CPU_Acquire( cpu_self );
while ( !_Chain_Is_empty( &cpu_self->Threads_in_need_for_help ) ) {
Chain_Node *node;
Thread_Control *the_thread;
ISR_lock_Context lock_context;
node = _Chain_Get_first_unprotected( &cpu_self->Threads_in_need_for_help );
_Chain_Set_off_chain( node );
the_thread = THREAD_OF_SCHEDULER_HELP_NODE( node );
_Per_CPU_Release( cpu_self );
_Thread_State_acquire( the_thread, &lock_context );
_Thread_Scheduler_ask_for_help( the_thread );
_Thread_State_release( the_thread, &lock_context );
_Per_CPU_Acquire( cpu_self );
}
_Per_CPU_Release( cpu_self );
#else
(void) cpu_self;
#endif
}
static void _Thread_Post_switch_cleanup( Thread_Control *executing )
{
#if defined(RTEMS_SMP)
Chain_Node *node;
const Chain_Node *tail;
if ( !_Thread_Can_ask_for_help( executing ) ) {
return;
}
node = _Chain_First( &executing->Scheduler.Scheduler_nodes );
tail = _Chain_Immutable_tail( &executing->Scheduler.Scheduler_nodes );
do {
Scheduler_Node *scheduler_node;
const Scheduler_Control *scheduler;
ISR_lock_Context lock_context;
scheduler_node = SCHEDULER_NODE_OF_THREAD_SCHEDULER_NODE( node );
scheduler = _Scheduler_Node_get_scheduler( scheduler_node );
_Scheduler_Acquire_critical( scheduler, &lock_context );
( *scheduler->Operations.reconsider_help_request )(
scheduler,
executing,
scheduler_node
);
_Scheduler_Release_critical( scheduler, &lock_context );
node = _Chain_Next( node );
} while ( node != tail );
#else
(void) executing;
#endif
}
static Thread_Action *_Thread_Get_post_switch_action(
Thread_Control *executing
)
{
Chain_Control *chain = &executing->Post_switch_actions.Chain;
return (Thread_Action *) _Chain_Get_unprotected( chain );
}
static void _Thread_Run_post_switch_actions( Thread_Control *executing )
{
ISR_lock_Context lock_context;
Thread_Action *action;
_Thread_State_acquire( executing, &lock_context );
_Thread_Post_switch_cleanup( executing );
action = _Thread_Get_post_switch_action( executing );
while ( action != NULL ) {
_Chain_Set_off_chain( &action->Node );
( *action->handler )( executing, action, &lock_context );
_Thread_State_acquire( executing, &lock_context );
action = _Thread_Get_post_switch_action( executing );
}
_Thread_State_release( executing, &lock_context );
}
void _Thread_Do_dispatch( Per_CPU_Control *cpu_self, ISR_Level level )
{
Thread_Control *executing;
_Assert( cpu_self->thread_dispatch_disable_level == 1 );
executing = cpu_self->executing;
do {
Thread_Control *heir;
_Thread_Preemption_intervention( cpu_self );
heir = _Thread_Get_heir_and_make_it_executing( cpu_self );
/*
* When the heir and executing are the same, then we are being
* requested to do the post switch dispatching. This is normally
* done to dispatch signals.
*/
if ( heir == executing )
goto post_switch;
/*
* Since heir and executing are not the same, we need to do a real
* context switch.
*/
#if __RTEMS_ADA__
executing->rtems_ada_self = rtems_ada_self;
rtems_ada_self = heir->rtems_ada_self;
#endif
if ( heir->budget_algorithm == THREAD_CPU_BUDGET_ALGORITHM_RESET_TIMESLICE )
heir->cpu_time_budget = rtems_configuration_get_ticks_per_timeslice();
/*
* On SMP the complete context switch must be atomic with respect to one
* processor. See also _Thread_Handler() since _Context_switch() may branch
* to this function.
*/
#if !defined( RTEMS_SMP )
_ISR_Local_enable( level );
#endif
_User_extensions_Thread_switch( executing, heir );
_Thread_Save_fp( executing );
_Context_Switch( &executing->Registers, &heir->Registers );
_Thread_Restore_fp( executing );
/*
* We have to obtain this value again after the context switch since the
* heir thread may have migrated from another processor. Values from the
* stack or non-volatile registers reflect the old execution environment.
*/
cpu_self = _Per_CPU_Get();
#if !defined( RTEMS_SMP )
_ISR_Local_disable( level );
#endif
} while (
#if defined( RTEMS_SMP )
false
#else
cpu_self->dispatch_necessary
#endif
);
post_switch:
_Assert( cpu_self->thread_dispatch_disable_level == 1 );
cpu_self->thread_dispatch_disable_level = 0;
_Profiling_Thread_dispatch_enable( cpu_self, 0 );
_ISR_Local_enable( level );
_Thread_Run_post_switch_actions( executing );
}
void _Thread_Dispatch( void )
{
ISR_Level level;
Per_CPU_Control *cpu_self;
_ISR_Local_disable( level );
cpu_self = _Per_CPU_Get();
if ( cpu_self->dispatch_necessary ) {
_Profiling_Thread_dispatch_disable( cpu_self, 0 );
cpu_self->thread_dispatch_disable_level = 1;
_Thread_Do_dispatch( cpu_self, level );
} else {
_ISR_Local_enable( level );
}
}
void _Thread_Dispatch_direct( Per_CPU_Control *cpu_self )
{
ISR_Level level;
if ( cpu_self->thread_dispatch_disable_level != 1 ) {
_Terminate(
INTERNAL_ERROR_CORE,
0,
INTERNAL_ERROR_BAD_THREAD_DISPATCH_DISABLE_LEVEL
);
}
_ISR_Local_disable( level );
_Thread_Do_dispatch( cpu_self, level );
}
|
