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| Rev | Author | Line No. | Line |
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| 1 | jermar | 1 | /* |
| 2 | * Copyright (C) 2001-2004 Jakub Jermar |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 29 | #include <mm/heap.h> |
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| 30 | #include <synch/spinlock.h> |
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| 31 | #include <func.h> |
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| 32 | #include <memstr.h> |
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| 68 | decky | 33 | #include <panic.h> |
| 1 | jermar | 34 | #include <arch/types.h> |
| 115 | jermar | 35 | #include <arch/asm.h> |
| 1 | jermar | 36 | |
| 37 | /* |
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| 38 | * First-fit algorithm. |
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| 39 | * Simple, but hopefully correct. |
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| 40 | * Chunks being freed are tested for mergability with their neighbours. |
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| 41 | */ |
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| 42 | |||
| 43 | static chunk_t *chunk0; |
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| 44 | static spinlock_t heaplock; |
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| 45 | |||
| 102 | jermar | 46 | void heap_init(__address heap, size_t size) |
| 1 | jermar | 47 | { |
| 48 | spinlock_initialize(&heaplock); |
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| 72 | decky | 49 | memsetb(heap, size, 0); |
| 1 | jermar | 50 | chunk0 = (chunk_t *) heap; |
| 51 | chunk0->used = 0; |
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| 52 | chunk0->size = size - sizeof(chunk_t); |
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| 53 | chunk0->next = NULL; |
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| 54 | chunk0->prev = NULL; |
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| 55 | } |
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| 56 | |||
| 57 | /* |
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| 58 | * Uses first-fit algorithm. |
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| 59 | */ |
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| 72 | decky | 60 | void *malloc(size_t size) |
| 1 | jermar | 61 | { |
| 62 | pri_t pri; |
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| 63 | chunk_t *x, *y, *z; |
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| 64 | |||
| 65 | if (size == 0) |
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| 102 | jermar | 66 | panic("zero-size allocation request"); |
| 1 | jermar | 67 | |
| 68 | x = chunk0; |
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| 69 | pri = cpu_priority_high(); |
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| 70 | spinlock_lock(&heaplock); |
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| 71 | while (x) { |
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| 72 | if (x->used || x->size < size) { |
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| 73 | x = x->next; |
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| 74 | continue; |
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| 75 | } |
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| 76 | |||
| 77 | x->used = 1; |
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| 78 | |||
| 79 | /* |
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| 80 | * If the chunk exactly matches required size or if truncating |
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| 81 | * it would not provide enough space for storing a new chunk |
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| 82 | * header plus at least one byte of data, we are finished. |
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| 83 | */ |
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| 84 | if (x->size < size + sizeof(chunk_t) + 1) { |
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| 85 | spinlock_unlock(&heaplock); |
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| 86 | cpu_priority_restore(pri); |
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| 87 | return &x->data[0]; |
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| 88 | } |
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| 89 | |||
| 90 | /* |
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| 91 | * Truncate x and create a new chunk. |
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| 92 | */ |
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| 93 | y = (chunk_t *) (((__address) x) + size + sizeof(chunk_t)); |
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| 94 | y->used = 0; |
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| 95 | y->size = x->size - size - sizeof(chunk_t); |
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| 96 | y->prev = x; |
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| 97 | y->next = NULL; |
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| 98 | |||
| 99 | if (z = x->next) { |
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| 100 | z->prev = y; |
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| 101 | y->next = z; |
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| 102 | } |
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| 103 | |||
| 104 | x->size = size; |
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| 105 | x->next = y; |
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| 106 | spinlock_unlock(&heaplock); |
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| 107 | cpu_priority_restore(pri); |
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| 108 | |||
| 109 | return &x->data[0]; |
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| 110 | } |
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| 111 | spinlock_unlock(&heaplock); |
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| 112 | cpu_priority_restore(pri); |
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| 113 | return NULL; |
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| 114 | } |
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| 115 | |||
| 116 | void free(void *ptr) |
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| 117 | { |
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| 118 | pri_t pri; |
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| 119 | chunk_t *x, *y, *z; |
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| 120 | |||
| 121 | if (!ptr) |
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| 122 | panic("free on NULL"); |
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| 123 | |||
| 124 | |||
| 125 | y = (chunk_t *) (((__u8 *) ptr) - sizeof(chunk_t)); |
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| 126 | if (y->used != 1) |
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| 127 | panic("freeing unused/damaged chunk"); |
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| 128 | |||
| 129 | pri = cpu_priority_high(); |
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| 130 | spinlock_lock(&heaplock); |
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| 131 | x = y->prev; |
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| 132 | z = y->next; |
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| 133 | /* merge x and y */ |
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| 134 | if (x && !x->used) { |
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| 135 | x->size += y->size + sizeof(chunk_t); |
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| 136 | x->next = z; |
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| 137 | if (z) |
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| 138 | z->prev = x; |
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| 139 | y = x; |
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| 140 | } |
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| 141 | /* merge y and z or merge (x merged with y) and z */ |
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| 142 | if (z && !z->used) { |
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| 143 | y->size += z->size + sizeof(chunk_t); |
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| 144 | y->next = z->next; |
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| 145 | if (z->next) { |
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| 146 | /* y is either y or x */ |
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| 147 | z->next->prev = y; |
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| 148 | } |
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| 149 | } |
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| 150 | y->used = 0; |
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| 151 | spinlock_unlock(&heaplock); |
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| 152 | cpu_priority_restore(pri); |
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| 153 | } |