| 1 | /* ----------------------------------------------------------------------- * |
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| 2 | * |
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| 3 | * Copyright 2001-2008 H. Peter Anvin - All Rights Reserved |
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| 4 | * |
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| 5 | * This program is free software; you can redistribute it and/or modify |
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| 6 | * it under the terms of the GNU General Public License as published by |
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| 7 | * the Free Software Foundation, Inc., 53 Temple Place Ste 330, |
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| 8 | * Boston MA 02111-1307, USA; either version 2 of the License, or |
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| 9 | * (at your option) any later version; incorporated herein by reference. |
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| 10 | * |
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| 11 | * ----------------------------------------------------------------------- */ |
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| 12 | |
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| 13 | /* |
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| 14 | * e820func.c |
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| 15 | * |
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| 16 | * E820 range database manager |
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| 17 | */ |
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| 18 | |
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| 19 | #include <stdint.h> |
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| 20 | #ifdef TEST |
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| 21 | #include <string.h> |
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| 22 | #else |
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| 23 | #include "memdisk.h" /* For memset() */ |
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| 24 | #endif |
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| 25 | #include "e820.h" |
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| 26 | |
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| 27 | #define MAXRANGES 1024 |
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| 28 | /* All of memory starts out as one range of "indeterminate" type */ |
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| 29 | struct e820range ranges[MAXRANGES]; |
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| 30 | int nranges; |
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| 31 | |
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| 32 | void e820map_init(void) |
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| 33 | { |
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| 34 | memset(ranges, 0, sizeof(ranges)); |
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| 35 | nranges = 1; |
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| 36 | ranges[1].type = -1U; |
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| 37 | } |
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| 38 | |
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| 39 | static void insertrange_at(int where, uint64_t start, uint32_t type) |
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| 40 | { |
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| 41 | int i; |
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| 42 | |
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| 43 | for (i = nranges; i > where; i--) |
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| 44 | ranges[i] = ranges[i - 1]; |
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| 45 | |
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| 46 | ranges[where].start = start; |
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| 47 | ranges[where].type = type; |
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| 48 | |
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| 49 | nranges++; |
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| 50 | ranges[nranges].start = 0ULL; |
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| 51 | ranges[nranges].type = -1U; |
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| 52 | } |
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| 53 | |
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| 54 | void insertrange(uint64_t start, uint64_t len, uint32_t type) |
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| 55 | { |
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| 56 | uint64_t last; |
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| 57 | uint32_t oldtype; |
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| 58 | int i, j; |
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| 59 | |
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| 60 | /* Remove this to make len == 0 mean all of memory */ |
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| 61 | if (len == 0) |
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| 62 | return; /* Nothing to insert */ |
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| 63 | |
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| 64 | last = start + len - 1; /* May roll over */ |
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| 65 | |
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| 66 | i = 0; |
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| 67 | oldtype = -2U; |
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| 68 | while (start > ranges[i].start && ranges[i].type != -1U) { |
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| 69 | oldtype = ranges[i].type; |
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| 70 | i++; |
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| 71 | } |
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| 72 | |
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| 73 | /* Consider the replacement policy. This current one is "overwrite." */ |
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| 74 | |
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| 75 | if (start < ranges[i].start || ranges[i].type == -1U) |
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| 76 | insertrange_at(i++, start, type); |
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| 77 | |
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| 78 | while (i == 0 || last > ranges[i].start - 1) { |
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| 79 | oldtype = ranges[i].type; |
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| 80 | ranges[i].type = type; |
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| 81 | i++; |
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| 82 | } |
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| 83 | |
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| 84 | if (last < ranges[i].start - 1) |
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| 85 | insertrange_at(i, last + 1, oldtype); |
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| 86 | |
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| 87 | /* Now the map is correct, but quite possibly not optimal. Scan the |
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| 88 | map for ranges which are redundant and remove them. */ |
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| 89 | i = j = 1; |
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| 90 | oldtype = ranges[0].type; |
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| 91 | while (i < nranges) { |
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| 92 | if (ranges[i].type == oldtype) { |
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| 93 | i++; |
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| 94 | } else { |
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| 95 | oldtype = ranges[i].type; |
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| 96 | if (i != j) |
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| 97 | ranges[j] = ranges[i]; |
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| 98 | i++; |
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| 99 | j++; |
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| 100 | } |
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| 101 | } |
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| 102 | |
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| 103 | if (i != j) { |
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| 104 | ranges[j] = ranges[i]; /* Termination sentinel copy */ |
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| 105 | nranges -= (i - j); |
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| 106 | } |
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| 107 | } |
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