source: trunk/hal/generic/hal_context.h @ 656

Last change on this file since 656 was 654, checked in by alain, 5 years ago

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1/*
2 * hal_context.h - Generic Thread Context Access API definition.
3 *
4 * Author  Alain Greiner    (2016,2017,2018,2019)
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_CONTEXT_H_
25#define  _HAL_CONTEXT_H_
26
27//////////////////////////////////////////////////////////////////////////////////////////
28//        Generic Thread Context API definition (implementation in hal_context.c)
29//
30// A thread context is defined by the two (core specific) structures hal_cpu_context_t
31// and hal_fpu_context_t, defined in hal_context.c file, that are accessed with generic
32// void* pointers stored in the thread descriptor.
33// - the "hal_cpu_context_t" struct saves the CPU registers values at context switch.
34// - the "hal_fpu_context_t" struct saves the FPU registers values at FPU switch.
35//////////////////////////////////////////////////////////////////////////////////////////
36
37/**** Forward declarations ****/
38
39struct thread_s;
40
41/****************************************************************************************
42 * This function allocates memory for a CPU context and links it to the thread
43 * identified by the <thread> argument. The context is not initialised.
44 ****************************************************************************************
45 * @ thread  : pointer on the thread descriptor.
46 * @ return 0 if success / return -1 if failure.
47 ***************************************************************************************/
48error_t hal_cpu_context_alloc( struct thread_s * thread );
49
50/****************************************************************************************
51 * This function initializes the CPU context of the thread identified by the <thread>
52 * argument. All slots required to start a new thread must be initialized.
53 ****************************************************************************************
54 * @ thread  : pointer on the thread descriptor.
55 ***************************************************************************************/
56void hal_cpu_context_init( struct thread_s * thread );
57
58/****************************************************************************************
59 * This function is called the sys_fork() function to complete the fork mechanism.
60 * It is called by th local parent thread to initialize the CPU context of the remote
61 * child thread, identified by the <thread_xp> argument.
62 * It makes three actions:
63 * 1) It copies the current values of the CPU registers of the core running the parent
64 *    thread to the remote child CPU context.
65 * 2) It patches four slots of this remote child CPU context:
66 *    - the c0_th   slot is set to the child thread descriptor pointer.
67 *    - the sp_29   slot is set to the child kernel stack pointer.
68 *    - the c0_sr   slot is set to kernel mode with IRQ disabled.
69 *    - the c2_ptpr slot is set to the child process GPT value.
70 * 3) It copies the content of the parent thread kernel_stack, to the child thread
71 *    kernel_stack, because the COW mechanism is not available on architectures where
72 *    the data MMU is de-activated in kernel mode.
73 ****************************************************************************************
74 * @ thread_xp  : extended pointer on the child thread descriptor.
75 ***************************************************************************************/
76void hal_cpu_context_fork( xptr_t    thread_xp );
77
78/****************************************************************************************
79 * This function is used to implement the exec() system call.
80 * 1) It initialize the relevant slots of the the calling thread CPU context.
81 * 2) It call the hal_do_cpu_restore() function to return to user mode and start
82 *    execution of the new process.
83 ****************************************************************************************
84 * @ thread  : pointer on the thread descriptor.
85 ***************************************************************************************/
86void hal_cpu_context_exec( struct thread_s * thread );
87
88/****************************************************************************************
89 * This function display some slots of the CPU context.
90 ****************************************************************************************
91 * @ thread_xp  : extended pointer on the thread descriptor.
92 ***************************************************************************************/
93void hal_cpu_context_display( xptr_t  thread_xp );
94
95/****************************************************************************************
96 * This function releases the physical memory allocated for a thread CPU context.
97 ****************************************************************************************
98 * @ thread  : pointer on the thread descriptor.
99 ***************************************************************************************/
100void hal_cpu_context_destroy( struct thread_s * thread );
101
102
103
104
105
106
107
108/****************************************************************************************
109 * This function allocates memory for a FPU context, reset all entries,
110 * and links it to the thread identified by the <thread> argument.
111 ****************************************************************************************
112 * @ thread  : pointer on the thread descriptor.
113 * @ return 0 if success / return -1 if failure.
114 ***************************************************************************************/
115error_t hal_fpu_context_alloc( struct thread_s * thread );
116
117/****************************************************************************************
118 * This function initializes a FPU context from scratch.
119 ****************************************************************************************
120 * @ thread  : pointer on the thread descriptor.
121 ***************************************************************************************/
122void hal_fpu_context_init( struct thread_s * thread );
123
124/****************************************************************************************
125 * This function copies a FPU context defined by the <src> argument to the FPU context
126 * defined by the <dst> argument. It is used by the fork system call.
127 ****************************************************************************************
128 * @ dst  : pointer on the destination thread descriptor.
129 * @ src  : pointer on the source thread descriptor.
130 ***************************************************************************************/
131void hal_fpu_context_copy( struct thread_s * dst,
132                           struct thread_s * src );
133
134/****************************************************************************************
135 * This function releases the physical memory allocated for a FPU context.
136 ****************************************************************************************
137 * @ thread  : pointer on the thread descriptor.
138 ***************************************************************************************/
139void hal_fpu_context_destroy( struct thread_s * thread );
140
141/****************************************************************************************
142 * This function is used to implement the fork() system call.
143 * It saves in a remote thread FPU context the current FPU registers values.
144 ****************************************************************************************
145 * @ thread_xp  : extended pointer on the remote thread descriptor.
146 ***************************************************************************************/
147void hal_fpu_context_save( xptr_t thread_xp );
148
149/****************************************************************************************
150 * This function restores from the calling thread FPU context the FPU registers values.
151 ****************************************************************************************
152 * @ thread  : pointer on the thread descriptor.
153 ***************************************************************************************/
154void hal_fpu_context_restore( struct thread_s * thread );
155
156#endif  /* _HAL_CONTEXT_H_ */
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