source: trunk/hal/generic/hal_context.h @ 426

Last change on this file since 426 was 408, checked in by alain, 7 years ago

Fix several bugs in the fork() syscall.
File size: 7.2 KB
Line 
1/*
2 * hal_context.h - Generic Thread Context Access API definition.
3 *
4 * Author  Alain Greiner    (2016)
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_context_t" struct is used for the CPU registers values at context switch.
34// - the "hal_fpu_context_t" struct is used for the FPU registers when required.
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 * @ return 0 if success / return -1 if failure.
46 ***************************************************************************************/
47error_t hal_cpu_context_alloc( struct thread_s * thread );
48
49/****************************************************************************************
50 * This function allocates memory for a CPU context, initialize it from scratch,
51 * and links it to the thread identified by the <thread> argument.
52 ****************************************************************************************
53 * @ thread  : pointer on the thread descriptor.
54 * @ return 0 if success / return -1 if failure.
55 ***************************************************************************************/
56error_t hal_cpu_context_create( struct thread_s * thread );
57
58/****************************************************************************************
59 * This function is used to implement the fork() system call.
60 * 1) It saves in a remote (child) thread CPU context the current CPU registers values.
61 *    Three slots are not simple copies of the parent registers values :
62 *    - the thread pointer is set to the child thread local pointer.
63 *    - the stack pointer is set to parrent SP + (child_base - parent_base).
64 *    - the status register is set to kernel mode with IRQ disabled.
65 * 2) It copies the content of the calling (parent) thread kernel_stack,
66 *    to the remote (child) thread kernel_stack.
67 ****************************************************************************************
68 * @ thread_xp  : extended pointer on the remote thread descriptor.
69 ***************************************************************************************/
70void hal_cpu_context_fork( xptr_t    thread_xp );
71
72/****************************************************************************************
73 * This function display some slots of the CPU context.
74 * - For the MIPS32 :
75 *   . GPR : gp_28 , sp_29 , ra_31
76 *   . CP0 : c0_sr , c0_th , c0_epc
77 *   . CP2 : c2_ptpr , c2-mode
78 * - For X86 TODO :
79 ****************************************************************************************
80 * @ thread_xp  : extended pointer on the thread descriptor.
81 ***************************************************************************************/
82void hal_cpu_context_display( xptr_t  thread_xp );
83
84/****************************************************************************************
85 * This function releases the physical memory allocated for a thread CPU context.
86 ****************************************************************************************
87 * @ thread  : pointer on the thread descriptor.
88 ***************************************************************************************/
89void hal_cpu_context_destroy( struct thread_s * thread );
90
91
92
93
94
95
96
97/****************************************************************************************
98 * This function allocates memory for a FPU context, reset all entries,
99 * and links it to the thread identified by the <thread> argument.
100 ****************************************************************************************
101 * @ thread  : pointer on the thread descriptor.
102 * @ return 0 if success / return -1 if failure.
103 ***************************************************************************************/
104error_t hal_fpu_context_alloc( struct thread_s * thread );
105
106/****************************************************************************************
107 * This function copies a FPU context defined by the <src> argument to the FPU context
108 * defined by the <dst> argument. It is used by the fork system call.
109 ****************************************************************************************
110 * @ dst  : pointer on the destination thread descriptor.
111 * @ src  : pointer on the source thread descriptor.
112 ***************************************************************************************/
113void hal_fpu_context_copy( struct thread_s * dst,
114                           struct thread_s * src );
115
116/****************************************************************************************
117 * This function releases the physical memory allocated for a FPU context.
118 ****************************************************************************************
119 * @ thread  : pointer on the thread descriptor.
120 ***************************************************************************************/
121void hal_fpu_context_destroy( struct thread_s * thread );
122
123/****************************************************************************************
124 * This function is used to implement the fork() system call.
125 * It saves in a remote thread FPU context the current FPU registers values.
126 ****************************************************************************************
127 * @ thread_xp  : extended pointer on the remote thread descriptor.
128 ***************************************************************************************/
129void hal_fpu_context_save( xptr_t thread_xp );
130
131/****************************************************************************************
132 * This function restores from the calling thread FPU context the FPU registers values.
133 ****************************************************************************************
134 * @ thread  : pointer on the thread descriptor.
135 ***************************************************************************************/
136void hal_fpu_context_restore( struct thread_s * thread );
137
138#endif  /* _HAL_CONTEXT_H_ */
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