3af006efb3
Previously, this was subject to races incrementing/decrementing the counter variable pendsv_lock. Technically, all that's needed here would be to make pendsv_lock an atomic counter. This implementation fulfils a stronger guarantee: it also provides mutual exclusion for the core which calls pendsv_suspend(). This is because the current use of pendsv_suspend/resume in MicroPython is to ensure exclusive access to softtimer data structures, and this does require mutual exclusion. The conceptually cleaner implementation would split the mutual exclusion part out into a softtimer-specific spinlock, but this increases the complexity and doesn't seem like it makes for a better implementation in the long run. This work was funded through GitHub Sponsors. Signed-off-by: Angus Gratton <angus@redyak.com.au>
56 lines
1.9 KiB
C
56 lines
1.9 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2022 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef MICROPY_INCLUDED_RP2_PENDSV_H
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#define MICROPY_INCLUDED_RP2_PENDSV_H
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#include <stddef.h>
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enum {
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PENDSV_DISPATCH_SOFT_TIMER,
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#if MICROPY_PY_NETWORK_CYW43
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PENDSV_DISPATCH_CYW43,
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#endif
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#if MICROPY_PY_NETWORK_WIZNET5K
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PENDSV_DISPATCH_WIZNET,
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#endif
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MICROPY_BOARD_PENDSV_ENTRIES
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PENDSV_DISPATCH_MAX
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};
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#define PENDSV_DISPATCH_NUM_SLOTS PENDSV_DISPATCH_MAX
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// PendSV IRQ priority, to run system-level tasks that preempt the main thread.
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#define IRQ_PRI_PENDSV PICO_LOWEST_IRQ_PRIORITY
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typedef void (*pendsv_dispatch_t)(void);
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void pendsv_init(void);
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void pendsv_suspend(void);
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void pendsv_resume(void);
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void pendsv_schedule_dispatch(size_t slot, pendsv_dispatch_t f);
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#endif // MICROPY_INCLUDED_RP2_PENDSV_H
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