source: trunk/hal/generic/hal_switch.h @ 407

Last change on this file since 407 was 407, checked in by alain, 5 years ago

First implementation of fork/exec.

File size: 3.3 KB
Line 
1/*
2 * hal_switch.h - Generic architecture context switch function
3 *
4 * Authorg   Alain Greiner  (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#ifndef _HAL_SWITCH_H_
25#define _HAL_SWITCH_H_
26
27struct thread_s;
28
29/*************************************************************************************
30 * The hal_do_cpu_switch() function is an assembly level function, called by the
31 * sched_yield() function, to make a CPU context switch.
32 * The current thread CPU context is identified by the <ctx_current> pointer.
33 * The new thread CPU context is identified by the <ctx_next> pointer.
34 * The architecture specific hal_cpu_context_t structure used to store a CPU context
35 * is defined in the architecture specific hal_context.c file.
36 * This function does NOT modify any register before saving values into context.
37 * When the switch is completed, it jumps to address contained in the relevant
38 * register of the new thread CPU context.
39 *************************************************************************************
40 * @ ctx_current  : local pointer on current thread CPU context.
41 * @ ctx_next     : local pointer on new thread CPU context.
42 ************************************************************************************/
43void hal_do_cpu_switch( void * ctx_old,
44                        void * ctx_new );
45
46/*************************************************************************************
47 * The hal_do_cpu_save() function is an assembly level function, called by the
48 * sys_fork() system call to save the parent thread register values to a child
49 * CPU context identified by the <ctx> pointer.
50 * This function does NOT modify any register before saving values into context.
51 * The architecture specific hal_cpu_context_t structure used to store a CPU context
52 * is defined in the architecture specific hal_context.c file.
53 * Two context slots are not saved from the calling thread registers values :
54 * - the "current_thread" slot is set from the value defined by the <thread> argument.
55 * - the "stack_pointer" slot is set by adding the value defined by the <offset>
56 *   argument to the current sp register value.
57 * When the save is completed, it simply returns to the calling function.
58 *************************************************************************************
59 * @ ctx     : local pointer on target thread CPU context.
60 * @ thread  : local pointer on target thread descriptor.
61 * @ offset  : kernel stack pointer offset (&child - &parent).
62 ************************************************************************************/
63void hal_do_cpu_save( void * ctx,
64                      void * thread,
65                      int    offset );
66
67#endif  /* _HAL_SWITCH_H_ */
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