[444] | 1 | /* sbrk.c -- allocate space on heap on OpenRISC 1000. |
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| 2 | * |
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| 3 | * Copyright (c) 2014 Authors |
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| 4 | * |
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| 5 | * Contributor Stefan Wallentowitz <stefan.wallentowitz@tum.de> |
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| 6 | * |
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| 7 | * The authors hereby grant permission to use, copy, modify, distribute, |
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| 8 | * and license this software and its documentation for any purpose, provided |
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| 9 | * that existing copyright notices are retained in all copies and that this |
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| 10 | * notice is included verbatim in any distributions. No written agreement, |
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| 11 | * license, or royalty fee is required for any of the authorized uses. |
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| 12 | * Modifications to this software may be copyrighted by their authors |
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| 13 | * and need not follow the licensing terms described here, provided that |
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| 14 | * the new terms are clearly indicated on the first page of each file where |
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| 15 | * they apply. |
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| 16 | */ |
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| 17 | |
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| 18 | #include <reent.h> |
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| 19 | |
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| 20 | #include "include/or1k-support.h" |
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| 21 | |
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| 22 | extern uint32_t end; /* Set by linker. */ |
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| 23 | uint32_t _or1k_heap_start = &end; |
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| 24 | uint32_t _or1k_heap_end; |
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| 25 | |
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| 26 | void * |
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| 27 | _sbrk_r (struct _reent * reent, ptrdiff_t incr) |
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| 28 | { |
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| 29 | uint32_t prev_heap_end; |
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| 30 | |
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| 31 | // This needs to be atomic |
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| 32 | |
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| 33 | // Disable interrupts on this core |
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| 34 | uint32_t sr_iee = or1k_interrupts_disable(); |
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| 35 | uint32_t sr_tee = or1k_timer_disable(); |
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| 36 | |
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| 37 | // Initialize heap end to end if not initialized before |
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| 38 | or1k_sync_cas((void*) &_or1k_heap_end, 0, (uint32_t) _or1k_heap_start); |
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| 39 | |
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| 40 | do { |
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| 41 | // Read previous heap end |
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| 42 | prev_heap_end = _or1k_heap_end; |
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| 43 | // and try to set it to the new value as long as it has changed |
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| 44 | } while (or1k_sync_cas((void*) &_or1k_heap_end, |
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| 45 | (uint32_t) prev_heap_end, |
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| 46 | (uint32_t) (prev_heap_end + incr)) != (uint32_t) prev_heap_end); |
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| 47 | |
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| 48 | // Restore interrupts on this core |
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| 49 | or1k_timer_restore(sr_tee); |
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| 50 | or1k_interrupts_restore(sr_iee); |
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| 51 | |
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| 52 | return (void*) prev_heap_end; |
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| 53 | } |
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