[1] | 1 | /* |
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| 2 | * hal_context.h - Generic Thread Context Access API definition. |
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| 3 | * |
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[625] | 4 | * Author Alain Greiner (2016,2017,2018,2019) |
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[1] | 5 | * |
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| 6 | * Copyright (c) UPMC Sorbonne Universites |
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| 7 | * |
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| 8 | * This file is part of ALMOS-MKH. |
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| 9 | * |
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| 10 | * ALMOS-MKH is free software; you can redistribute it and/or modify it |
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| 11 | * under the terms of the GNU General Public License as published by |
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| 12 | * the Free Software Foundation; version 2.0 of the License. |
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| 13 | * |
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| 14 | * ALMOS-MKH is distributed in the hope that it will be useful, but |
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| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 17 | * General Public License for more details. |
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| 18 | * |
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| 19 | * You should have received a copy of the GNU General Public License |
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| 20 | * along with ALMOS-MKH; if not, write to the Free Software Foundation, |
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| 21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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| 22 | */ |
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| 23 | |
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| 24 | #ifndef _HAL_CONTEXT_H_ |
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| 25 | #define _HAL_CONTEXT_H_ |
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| 26 | |
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| 27 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 28 | // Generic Thread Context API definition (implementation in hal_context.c) |
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| 29 | // |
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[151] | 30 | // A thread context is defined by the two (core specific) structures hal_cpu_context_t |
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| 31 | // and hal_fpu_context_t, defined in hal_context.c file, that are accessed with generic |
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[1] | 32 | // void* pointers stored in the thread descriptor. |
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[625] | 33 | // - the "hal_cpu_context_t" struct saves the CPU registers values at context switch. |
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| 34 | // - the "hal_fpu_context_t" struct saves the FPU registers values at FPU switch. |
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[1] | 35 | ////////////////////////////////////////////////////////////////////////////////////////// |
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| 36 | |
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| 37 | /**** Forward declarations ****/ |
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| 38 | |
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| 39 | struct thread_s; |
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| 40 | |
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| 41 | /**************************************************************************************** |
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[407] | 42 | * This function allocates memory for a CPU context and links it to the thread |
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| 43 | * identified by the <thread> argument. The context is not initialised. |
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[1] | 44 | **************************************************************************************** |
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[457] | 45 | * @ thread : pointer on the thread descriptor. |
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[407] | 46 | * @ return 0 if success / return -1 if failure. |
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| 47 | ***************************************************************************************/ |
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| 48 | error_t hal_cpu_context_alloc( struct thread_s * thread ); |
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| 49 | |
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| 50 | /**************************************************************************************** |
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[457] | 51 | * This function initializes a CPU context from scratch. |
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[407] | 52 | **************************************************************************************** |
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[1] | 53 | * @ thread : pointer on the thread descriptor. |
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| 54 | ***************************************************************************************/ |
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[457] | 55 | void hal_cpu_context_init( struct thread_s * thread ); |
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[1] | 56 | |
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| 57 | /**************************************************************************************** |
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[625] | 58 | * This function is called the sys_fork() function to complete the fork mechanism. |
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| 59 | * It is called by th local parent thread to initialize the CPU context of the remote |
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| 60 | * child thread, identified by the <thread_xp> argument. |
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| 61 | * It makes three actions: |
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| 62 | * 1) It copies the current values of the CPU registers of the core running the parent |
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| 63 | * thread to the remote child CPU context. |
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| 64 | * 2) It patches four slots of this remote child CPU context: |
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| 65 | * - the c0_th slot is set to the child thread descriptor pointer. |
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| 66 | * - the sp_29 slot is set to the child kernel stack pointer. |
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| 67 | * - the c0_sr slot is set to kernel mode with IRQ disabled. |
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| 68 | * - the c2_ptpr slot is set to the child process GPT value. |
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| 69 | * 3) It copies the content of the parent thread kernel_stack, to the child thread |
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| 70 | * kernel_stack, because the COW mechanism is not available on architectures where |
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| 71 | * the data MMU is de-activated in kernel mode. |
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[1] | 72 | **************************************************************************************** |
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[625] | 73 | * @ thread_xp : extended pointer on the child thread descriptor. |
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[1] | 74 | ***************************************************************************************/ |
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[408] | 75 | void hal_cpu_context_fork( xptr_t thread_xp ); |
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[1] | 76 | |
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| 77 | /**************************************************************************************** |
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[457] | 78 | * This function is used to implement the exec() system call. |
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| 79 | * 1) It initialize the relevant slots of the the calling thread CPU context. |
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| 80 | * 2) It call the hal_do_cpu_restore() function to return to user mode and start |
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| 81 | * execution of the new process. |
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| 82 | **************************************************************************************** |
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| 83 | * @ thread : pointer on the thread descriptor. |
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| 84 | ***************************************************************************************/ |
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| 85 | void hal_cpu_context_exec( struct thread_s * thread ); |
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| 86 | |
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| 87 | /**************************************************************************************** |
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[408] | 88 | * This function display some slots of the CPU context. |
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| 89 | **************************************************************************************** |
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| 90 | * @ thread_xp : extended pointer on the thread descriptor. |
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| 91 | ***************************************************************************************/ |
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| 92 | void hal_cpu_context_display( xptr_t thread_xp ); |
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| 93 | |
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| 94 | /**************************************************************************************** |
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[1] | 95 | * This function releases the physical memory allocated for a thread CPU context. |
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| 96 | **************************************************************************************** |
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| 97 | * @ thread : pointer on the thread descriptor. |
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| 98 | ***************************************************************************************/ |
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| 99 | void hal_cpu_context_destroy( struct thread_s * thread ); |
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| 100 | |
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| 101 | |
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| 102 | |
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[407] | 103 | |
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| 104 | |
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| 105 | |
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| 106 | |
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[1] | 107 | /**************************************************************************************** |
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[407] | 108 | * This function allocates memory for a FPU context, reset all entries, |
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| 109 | * and links it to the thread identified by the <thread> argument. |
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[1] | 110 | **************************************************************************************** |
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| 111 | * @ thread : pointer on the thread descriptor. |
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[407] | 112 | * @ return 0 if success / return -1 if failure. |
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[1] | 113 | ***************************************************************************************/ |
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[407] | 114 | error_t hal_fpu_context_alloc( struct thread_s * thread ); |
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[1] | 115 | |
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| 116 | /**************************************************************************************** |
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[457] | 117 | * This function initializes a FPU context from scratch. |
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| 118 | **************************************************************************************** |
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| 119 | * @ thread : pointer on the thread descriptor. |
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| 120 | ***************************************************************************************/ |
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| 121 | void hal_fpu_context_init( struct thread_s * thread ); |
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| 122 | |
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| 123 | /**************************************************************************************** |
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[407] | 124 | * This function copies a FPU context defined by the <src> argument to the FPU context |
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| 125 | * defined by the <dst> argument. It is used by the fork system call. |
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[1] | 126 | **************************************************************************************** |
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| 127 | * @ dst : pointer on the destination thread descriptor. |
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| 128 | * @ src : pointer on the source thread descriptor. |
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| 129 | ***************************************************************************************/ |
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[407] | 130 | void hal_fpu_context_copy( struct thread_s * dst, |
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[1] | 131 | struct thread_s * src ); |
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| 132 | |
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| 133 | /**************************************************************************************** |
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| 134 | * This function releases the physical memory allocated for a FPU context. |
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| 135 | **************************************************************************************** |
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| 136 | * @ thread : pointer on the thread descriptor. |
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| 137 | ***************************************************************************************/ |
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| 138 | void hal_fpu_context_destroy( struct thread_s * thread ); |
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| 139 | |
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| 140 | /**************************************************************************************** |
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[408] | 141 | * This function is used to implement the fork() system call. |
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| 142 | * It saves in a remote thread FPU context the current FPU registers values. |
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[1] | 143 | **************************************************************************************** |
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[408] | 144 | * @ thread_xp : extended pointer on the remote thread descriptor. |
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[1] | 145 | ***************************************************************************************/ |
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[408] | 146 | void hal_fpu_context_save( xptr_t thread_xp ); |
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[1] | 147 | |
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| 148 | /**************************************************************************************** |
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[408] | 149 | * This function restores from the calling thread FPU context the FPU registers values. |
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[1] | 150 | **************************************************************************************** |
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| 151 | * @ thread : pointer on the thread descriptor. |
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| 152 | ***************************************************************************************/ |
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| 153 | void hal_fpu_context_restore( struct thread_s * thread ); |
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| 154 | |
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| 155 | #endif /* _HAL_CONTEXT_H_ */ |
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