| 1 | /* |
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| 2 | * barrier.h - Busy-waiting, local, kernel barrier definition |
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| 3 | * |
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| 4 | * Author Alain Greiner (2016,2017,2018) |
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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 _BARRIER_H_ |
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| 25 | #define _BARRIER_H_ |
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| 26 | |
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| 27 | #include <kernel_config.h> |
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| 28 | #include <hal_kernel_types.h> |
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| 29 | |
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| 30 | /***************************************************************************************** |
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| 31 | * This structure defines a "rendez-vous" barrier, that can be used |
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| 32 | * to synchronise several kernel threads running in the same cluster. |
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| 33 | * As it is used in the kernel_init phase, it implements a busy-waiting policy. |
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| 34 | * It does not need to be initialised, but it must be statically allocated |
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| 35 | * in the KDATA segment to be properly initialised by the compiler/loader. |
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| 36 | ****************************************************************************************/ |
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| 37 | |
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| 38 | typedef struct barrier_s |
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| 39 | { |
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| 40 | uint32_t current; // number of arrived threads |
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| 41 | volatile uint32_t sense; // barrier state (toggle) |
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| 42 | uint32_t padding[(CONFIG_CACHE_LINE_SIZE>>2)-2]; |
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| 43 | } |
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| 44 | barrier_t; |
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| 45 | |
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| 46 | /***************************************************************************************** |
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| 47 | * This blocking function implements a toggle barrier. It returns only when all |
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| 48 | * expected threads reach the barrier. It can be used several times without |
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| 49 | * specific initialisation. |
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| 50 | ***************************************************************************************** |
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| 51 | * @ barrier : pointer on barrier |
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| 52 | * @ count : number of expected thread |
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| 53 | ****************************************************************************************/ |
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| 54 | inline void barrier_wait( barrier_t * barrier, |
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| 55 | uint32_t count ); |
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| 56 | |
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| 57 | |
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| 58 | #endif /* _BARRIER_H_ */ |
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