source: trunk/hal/generic/hal_context.h @ 686

Last change on this file since 686 was 679, checked in by alain, 4 years ago

Mainly cosmetic.
File size: 8.8 KB
Line 
1/*
2 * hal_context.h - Generic Thread Context Access API definition.
3 *
4 * Author  Alain Greiner    (2016,2017,2018,2019,2020)
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 from the <thread> descriptor, depending on the thread type (user / kernel).
53 * All slots required to start a new thread must be initialized in the thread context.
54 * Moreover, for an user thread, the arguments to be passed to the entry function
55 * depend on the <is_main> argument below:
56 * - a main thread, created by sys_exec(), requires two arguments, defined by the two
57 *   <argc> and <argv> arguments below.
58 *   define the arguments
59 * - a pthread, created by sys_thread_create() requires only one argument, defined by
60 *   the "entry_args" field in the thread descriptor.
61 ****************************************************************************************
62 * @ thread  : pointer on the thread descriptor.
63 * @ is_main : main thread when non zero.
64 * @ argc    : actual number of arguments (for main).
65 * @ argv    : user space pointer on array of pointers on strings arguments (for main).
66 ***************************************************************************************/
67void hal_cpu_context_init( struct thread_s * thread,
68                           bool_t            is_main,
69                           uint32_t          argc,
70                           intptr_t          argv );
71
72/****************************************************************************************
73 * This function is called the sys_fork() function to complete the fork mechanism.
74 * It is called by th local parent thread to initialize the CPU context of the remote
75 * child thread, identified by the <thread_xp> argument.
76 * It makes three actions:
77 * 1) It copies the current values of the CPU registers of the core running the parent
78 *    thread to the remote child CPU context.
79 * 2) It patches four slots of this remote child CPU context:
80 *    - the c0_th   slot is set to the child thread descriptor pointer.
81 *    - the sp_29   slot is set to the child kernel stack pointer.
82 *    - the c0_sr   slot is set to kernel mode with IRQ disabled.
83 *    - the c2_ptpr slot is set to the child process GPT value.
84 * 3) It copies the content of the parent thread kernel_stack, to the child thread
85 *    kernel_stack, because the COW mechanism is not available on architectures where
86 *    the data MMU is de-activated in kernel mode.
87 ****************************************************************************************
88 * @ thread_xp  : extended pointer on the child thread descriptor.
89 ***************************************************************************************/
90void hal_cpu_context_fork( xptr_t    thread_xp );
91
92/****************************************************************************************
93 * This function display some slots of the CPU context.
94 ****************************************************************************************
95 * @ thread_xp  : extended pointer on the thread descriptor.
96 ***************************************************************************************/
97void hal_cpu_context_display( xptr_t  thread_xp );
98
99/****************************************************************************************
100 * This function releases the physical memory allocated for a thread CPU context.
101 ****************************************************************************************
102 * @ thread  : pointer on the thread descriptor.
103 ***************************************************************************************/
104void hal_cpu_context_destroy( struct thread_s * thread );
105
106
107
108
109
110
111
112/****************************************************************************************
113 * This function allocates memory for a FPU context, reset all entries,
114 * and links it to the thread identified by the <thread> argument.
115 ****************************************************************************************
116 * @ thread  : pointer on the thread descriptor.
117 * @ return 0 if success / return -1 if failure.
118 ***************************************************************************************/
119error_t hal_fpu_context_alloc( struct thread_s * thread );
120
121/****************************************************************************************
122 * This function initializes a FPU context from scratch.
123 ****************************************************************************************
124 * @ thread  : pointer on the thread descriptor.
125 ***************************************************************************************/
126void hal_fpu_context_init( struct thread_s * thread );
127
128/****************************************************************************************
129 * This function copies a FPU context defined by the <src> argument to the FPU context
130 * defined by the <dst> argument. It is used by the fork system call.
131 ****************************************************************************************
132 * @ dst  : pointer on the destination thread descriptor.
133 * @ src  : pointer on the source thread descriptor.
134 ***************************************************************************************/
135void hal_fpu_context_copy( struct thread_s * dst,
136                           struct thread_s * src );
137
138/****************************************************************************************
139 * This function releases the physical memory allocated for a FPU context.
140 ****************************************************************************************
141 * @ thread  : pointer on the thread descriptor.
142 ***************************************************************************************/
143void hal_fpu_context_destroy( struct thread_s * thread );
144
145/****************************************************************************************
146 * This function is used to implement the fork() system call.
147 * It saves in a remote thread FPU context the current FPU registers values.
148 ****************************************************************************************
149 * @ thread_xp  : extended pointer on the remote thread descriptor.
150 ***************************************************************************************/
151void hal_fpu_context_save( xptr_t thread_xp );
152
153/****************************************************************************************
154 * This function restores from the calling thread FPU context the FPU registers values.
155 ****************************************************************************************
156 * @ thread  : pointer on the thread descriptor.
157 ***************************************************************************************/
158void hal_fpu_context_restore( struct thread_s * thread );
159
160#endif  /* _HAL_CONTEXT_H_ */
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