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| Rev | Author | Line No. | Line |
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| 126 | decky | 1 | /* |
| 127 | jermar | 2 | * Copyright (C) 2005 Martin Decky |
| 126 | decky | 3 | * All rights reserved. |
| 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 | |||
| 391 | jermar | 29 | #include <arch/mm/asid.h> |
| 30 | #include <synch/spinlock.h> |
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| 126 | decky | 31 | #include <arch.h> |
| 391 | jermar | 32 | #include <debug.h> |
| 126 | decky | 33 | |
| 391 | jermar | 34 | #define ASIDS 256 |
| 126 | decky | 35 | |
| 391 | jermar | 36 | static spinlock_t asid_usage_lock; |
| 37 | static count_t asid_usage[ASIDS]; /**< Usage tracking array for ASIDs */ |
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| 126 | decky | 38 | |
| 391 | jermar | 39 | /** Get ASID |
| 126 | decky | 40 | * |
| 391 | jermar | 41 | * Get the least used ASID. |
| 42 | * |
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| 43 | * @return ASID |
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| 126 | decky | 44 | */ |
| 391 | jermar | 45 | asid_t asid_get(void) |
| 126 | decky | 46 | { |
| 391 | jermar | 47 | pri_t pri; |
| 48 | int i, j; |
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| 49 | count_t min; |
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| 50 | |||
| 51 | min = (unsigned) -1; |
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| 52 | |||
| 53 | pri = cpu_priority_high(); |
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| 54 | spinlock_lock(&asid_usage_lock); |
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| 55 | |||
| 56 | for (i=0, j = 0; (i<ASIDS); i++) { |
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| 57 | if (asid_usage[i] < min) { |
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| 58 | j = i; |
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| 59 | min = asid_usage[i]; |
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| 60 | if (!min) |
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| 61 | break; |
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| 62 | } |
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| 63 | } |
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| 64 | |||
| 65 | asid_usage[i]++; |
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| 66 | |||
| 67 | spinlock_unlock(&asid_usage_lock); |
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| 68 | cpu_priority_restore(pri); |
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| 69 | |||
| 70 | return i; |
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| 126 | decky | 71 | } |
| 72 | |||
| 391 | jermar | 73 | /** Release ASID |
| 126 | decky | 74 | * |
| 391 | jermar | 75 | * Release ASID by decrementing its usage count. |
| 76 | * |
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| 77 | * @param asid ASID. |
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| 126 | decky | 78 | */ |
| 391 | jermar | 79 | void asid_put(asid_t asid) |
| 126 | decky | 80 | { |
| 391 | jermar | 81 | pri_t pri; |
| 82 | |||
| 83 | pri = cpu_priority_high(); |
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| 84 | spinlock_lock(&asid_usage_lock); |
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| 85 | |||
| 86 | ASSERT(asid_usage[asid] > 0); |
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| 87 | asid_usage[asid]--; |
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| 88 | |||
| 89 | spinlock_unlock(&asid_usage_lock); |
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| 90 | cpu_priority_restore(pri); |
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| 126 | decky | 91 | } |