| 1 | /*
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| 2 | * hal_switch.h - Generic architecture context switch function
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| 3 | *
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| 4 | * Authorg Alain Greiner (2017)
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| 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_SWITCH_H_
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| 25 | #define _HAL_SWITCH_H_
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| 26 |
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| 27 | struct thread_s;
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| 28 |
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| 29 | /*************************************************************************************
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| 30 | * This assembly level function is called by the sched_yield() function,
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| 31 | * to make a CPU context switch.
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| 32 | * The current thread CPU context is identified by the <ctx_old> pointer.
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| 33 | * The new thread CPU context is identified by the <ctx_new> pointer.
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| 34 | * The architecture specific hal_cpu_context_t structure used to store a CPU context
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| 35 | * is defined in the architecture specific hal_context.c file.
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| 36 | * This function does NOT modify any register before saving values into context.
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| 37 | * When the switch is completed, it jumps to address contained in the relevant
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| 38 | * register of the new thread CPU context.
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| 39 | *************************************************************************************
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| 40 | * @ ctx_current : local pointer on current thread CPU context.
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| 41 | * @ ctx_next : local pointer on new thread CPU context.
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| 42 | ************************************************************************************/
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| 43 | void hal_do_cpu_switch( void * ctx_old,
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| 44 | void * ctx_new );
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| 45 |
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| 46 | /*************************************************************************************
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| 47 | * This assembly level function is called by the hal_cpu_context_fork() function.
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| 48 | * It save the calling CPU register values to a CPU context identified by <ctx>.
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| 49 | * This function does NOT modify any register before saving values into context.
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| 50 | * The architecture specific hal_cpu_context_t structure used to store a CPU context
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| 51 | * is defined in the architecture specific hal_context.c file.
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| 52 | * When the save is completed, it simply returns to the calling function.
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| 53 | *************************************************************************************
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| 54 | * @ ctx : local pointer on CPU context.
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| 55 | ************************************************************************************/
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| 56 | void hal_do_cpu_save( void * ctx );
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| 57 |
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| 58 | /*************************************************************************************
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| 59 | * This assembly level function, is called by the hal_cpu_context_exec() function.
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| 60 | * It restore the calling CPU register values from a CPU context identified by <ctx>.
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| 61 | * The architecture specific hal_cpu_context_t structure used to store a CPU context
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| 62 | * is defined in the architecture specific hal_context.c file.
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| 63 | * When the restore is completed, it simply jumps to the address contained in ra_31.
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| 64 | * In ALMOS-MKH, ra_31 must contain a pointer on the eret() function, and c0_epc
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| 65 | * must contain the new main thread entry point.
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| 66 | *************************************************************************************
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| 67 | * @ ctx : local pointer on CPU context.
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| 68 | ************************************************************************************/
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| 69 | void hal_do_cpu_restore( void * ctx );
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| 70 |
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| 71 | #endif /* _HAL_SWITCH_H_ */
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