106 lines
2.5 KiB
C
106 lines
2.5 KiB
C
#ident "$Id: e820func.c,v 1.7 2004/12/14 22:46:25 hpa Exp $"
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/* ----------------------------------------------------------------------- *
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*
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* Copyright 2001 H. Peter Anvin - All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
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* Boston MA 02111-1307, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/*
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* e820func.c
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*
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* E820 range database manager
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*/
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#include <stdint.h>
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#include "memdisk.h" /* For memset() */
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#include "e820.h"
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#define MAXRANGES 64
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/* All of memory starts out as one range of "indeterminate" type */
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struct e820range ranges[MAXRANGES];
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int nranges;
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void e820map_init(void)
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{
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memset(ranges, 0, sizeof(ranges));
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nranges = 1;
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ranges[1].type = -1;
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}
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static void insertrange_at(int where, uint64_t start, uint32_t type)
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{
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int i;
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for ( i = nranges ; i > where ; i-- )
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ranges[i] = ranges[i-1];
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ranges[where].start = start;
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ranges[where].type = type;
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nranges++;
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ranges[nranges].start = 0ULL;
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ranges[nranges].type = (uint32_t)-1;
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}
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void insertrange(uint64_t start, uint64_t len, uint32_t type)
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{
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uint64_t last;
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uint32_t oldtype;
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int i, j;
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/* Remove this to make len == 0 mean all of memory */
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if ( len == 0 )
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return; /* Nothing to insert */
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last = start+len-1; /* May roll over */
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i = 0;
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oldtype = -2;
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while ( start > ranges[i].start && ranges[i].type != -1 ) {
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oldtype = ranges[i].type;
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i++;
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}
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/* Consider the replacement policy. This current one is "overwrite." */
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if ( start < ranges[i].start || ranges[i].type == -1 )
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insertrange_at(i++, start, type);
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while ( i == 0 || last > ranges[i].start-1 ) {
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oldtype = ranges[i].type;
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ranges[i].type = type;
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i++;
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}
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if ( last < ranges[i].start-1 )
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insertrange_at(i, last+1, oldtype);
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/* Now the map is correct, but quite possibly not optimal. Scan the
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map for ranges which are redundant and remove them. */
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i = j = 1;
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oldtype = ranges[0].type;
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while ( i < nranges ) {
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if ( ranges[i].type == oldtype ) {
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i++;
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} else {
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oldtype = ranges[i].type;
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if ( i != j )
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ranges[j] = ranges[i];
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i++; j++;
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}
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}
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if ( i != j ) {
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ranges[j] = ranges[i]; /* Termination sentinel copy */
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nranges -= (i-j);
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}
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}
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