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1 | /*- |
2 | * Copyright (c) 1982, 1986 The Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * %sccs.include.proprietary.c% | |
da7c5cc6 | 6 | * |
4e3656e7 | 7 | * @(#)subr_rmap.c 7.9 (Berkeley) %G% |
da7c5cc6 | 8 | */ |
2694e78a | 9 | |
94368568 JB |
10 | #include "param.h" |
11 | #include "systm.h" | |
12 | #include "map.h" | |
8429d022 | 13 | #include "dmap.h" /* XXX */ |
94368568 | 14 | #include "proc.h" |
94368568 | 15 | #include "kernel.h" |
2694e78a | 16 | |
b725a0ca BJ |
17 | /* |
18 | * Resource map handling routines. | |
19 | * | |
20 | * A resource map is an array of structures each | |
21 | * of which describes a segment of the address space of an available | |
22 | * resource. The segments are described by their base address and | |
23 | * length, and sorted in address order. Each resource map has a fixed | |
24 | * maximum number of segments allowed. Resources are allocated | |
25 | * by taking part or all of one of the segments of the map. | |
26 | * | |
27 | * Returning of resources will require another segment if | |
28 | * the returned resources are not adjacent in the address | |
29 | * space to an existing segment. If the return of a segment | |
30 | * would require a slot which is not available, then one of | |
31 | * the resource map segments is discarded after a warning is printed. | |
32 | * Returning of resources may also cause the map to collapse | |
33 | * by coalescing two existing segments and the returned space | |
34 | * into a single segment. In this case the resource map is | |
35 | * made smaller by copying together to fill the resultant gap. | |
36 | * | |
37 | * N.B.: the current implementation uses a dense array and does | |
38 | * not admit the value ``0'' as a legal address, since that is used | |
39 | * as a delimiter. | |
40 | */ | |
41 | ||
42 | /* | |
43 | * Initialize map mp to have (mapsize-2) segments | |
44 | * and to be called ``name'', which we print if | |
45 | * the slots become so fragmented that we lose space. | |
46 | * The map itself is initialized with size elements free | |
47 | * starting at addr. | |
48 | */ | |
49 | rminit(mp, size, addr, name, mapsize) | |
50 | register struct map *mp; | |
a29f7995 | 51 | long size, addr; |
b725a0ca BJ |
52 | char *name; |
53 | int mapsize; | |
54 | { | |
55 | register struct mapent *ep = (struct mapent *)(mp+1); | |
56 | ||
57 | mp->m_name = name; | |
58 | /* N.B.: WE ASSUME HERE THAT sizeof (struct map) == sizeof (struct mapent) */ | |
59 | /* | |
60 | * One of the mapsize slots is taken by the map structure, | |
61 | * segments has size 0 and addr 0, and acts as a delimiter. | |
62 | * We insure that we never use segments past the end of | |
63 | * the array which is given by mp->m_limit. | |
64 | * Instead, when excess segments occur we discard some resources. | |
65 | */ | |
66 | mp->m_limit = (struct mapent *)&mp[mapsize]; | |
67 | /* | |
68 | * Simulate a rmfree(), but with the option to | |
69 | * call with size 0 and addr 0 when we just want | |
70 | * to initialize without freeing. | |
71 | */ | |
72 | ep->m_size = size; | |
73 | ep->m_addr = addr; | |
92d92331 MK |
74 | (++ep)->m_size = 0; |
75 | ep->m_addr = 0; | |
b725a0ca BJ |
76 | } |
77 | ||
2694e78a | 78 | /* |
4e3656e7 KM |
79 | * A piece of memory of at least size units is allocated from the |
80 | * specified map using a first-fit algorithm. It returns the starting | |
81 | * address of the allocated space. | |
b725a0ca | 82 | * |
4e3656e7 | 83 | * This routine knows about and handles the interleaving of the swapmap. |
2694e78a | 84 | */ |
39d536e6 | 85 | long |
b725a0ca BJ |
86 | rmalloc(mp, size) |
87 | register struct map *mp; | |
39d536e6 | 88 | long size; |
2694e78a | 89 | { |
b725a0ca BJ |
90 | register struct mapent *ep = (struct mapent *)(mp+1); |
91 | register int addr; | |
92 | register struct mapent *bp; | |
41888f16 | 93 | swblk_t first, rest; |
2694e78a | 94 | |
d668d9ba | 95 | if (size <= 0 || mp == swapmap && size > dmmax) |
b725a0ca BJ |
96 | panic("rmalloc"); |
97 | /* | |
98 | * Search for a piece of the resource map which has enough | |
99 | * free space to accomodate the request. | |
100 | */ | |
101 | for (bp = ep; bp->m_size; bp++) { | |
2694e78a | 102 | if (bp->m_size >= size) { |
b725a0ca BJ |
103 | /* |
104 | * If allocating from swapmap, | |
105 | * then have to respect interleaving | |
106 | * boundaries. | |
107 | */ | |
d668d9ba | 108 | if (mp == swapmap && nswdev > 1 && |
c1954620 | 109 | (first = dmmax - bp->m_addr%dmmax) < size) { |
41888f16 BJ |
110 | if (bp->m_size - first < size) |
111 | continue; | |
b725a0ca | 112 | addr = bp->m_addr + first; |
41888f16 BJ |
113 | rest = bp->m_size - first - size; |
114 | bp->m_size = first; | |
115 | if (rest) | |
b725a0ca BJ |
116 | rmfree(swapmap, rest, addr+size); |
117 | return (addr); | |
41888f16 | 118 | } |
b725a0ca BJ |
119 | /* |
120 | * Allocate from the map. | |
121 | * If there is no space left of the piece | |
122 | * we allocated from, move the rest of | |
123 | * the pieces to the left. | |
124 | */ | |
125 | addr = bp->m_addr; | |
2694e78a BJ |
126 | bp->m_addr += size; |
127 | if ((bp->m_size -= size) == 0) { | |
128 | do { | |
129 | bp++; | |
130 | (bp-1)->m_addr = bp->m_addr; | |
131 | } while ((bp-1)->m_size = bp->m_size); | |
132 | } | |
b725a0ca BJ |
133 | if (mp == swapmap && addr % CLSIZE) |
134 | panic("rmalloc swapmap"); | |
135 | return (addr); | |
2694e78a BJ |
136 | } |
137 | } | |
b725a0ca | 138 | return (0); |
2694e78a BJ |
139 | } |
140 | ||
141 | /* | |
4e3656e7 KM |
142 | * The previously allocated space at addr of size units is freed |
143 | * into the specified map. This routine is responsible for sorting | |
144 | * the frred space into the correct location in the map, and coalescing | |
145 | * it with free space on either side if they adjoin. | |
2694e78a | 146 | */ |
b725a0ca BJ |
147 | rmfree(mp, size, addr) |
148 | struct map *mp; | |
39d536e6 | 149 | long size, addr; |
2694e78a | 150 | { |
b725a0ca BJ |
151 | struct mapent *firstbp; |
152 | register struct mapent *bp; | |
2694e78a BJ |
153 | register int t; |
154 | ||
b725a0ca BJ |
155 | /* |
156 | * Both address and size must be | |
157 | * positive, or the protocol has broken down. | |
158 | */ | |
159 | if (addr <= 0 || size <= 0) | |
160 | goto badrmfree; | |
161 | /* | |
162 | * Locate the piece of the map which starts after the | |
163 | * returned space (or the end of the map). | |
164 | */ | |
165 | firstbp = bp = (struct mapent *)(mp + 1); | |
166 | for (; bp->m_addr <= addr && bp->m_size != 0; bp++) | |
2694e78a | 167 | continue; |
b725a0ca BJ |
168 | /* |
169 | * If the piece on the left abuts us, | |
170 | * then we should combine with it. | |
171 | */ | |
172 | if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) { | |
173 | /* | |
174 | * Check no overlap (internal error). | |
175 | */ | |
176 | if ((bp-1)->m_addr+(bp-1)->m_size > addr) | |
177 | goto badrmfree; | |
178 | /* | |
179 | * Add into piece on the left by increasing its size. | |
180 | */ | |
2694e78a | 181 | (bp-1)->m_size += size; |
b725a0ca BJ |
182 | /* |
183 | * If the combined piece abuts the piece on | |
184 | * the right now, compress it in also, | |
185 | * by shifting the remaining pieces of the map over. | |
186 | */ | |
187 | if (bp->m_addr && addr+size >= bp->m_addr) { | |
188 | if (addr+size > bp->m_addr) | |
189 | goto badrmfree; | |
2694e78a BJ |
190 | (bp-1)->m_size += bp->m_size; |
191 | while (bp->m_size) { | |
192 | bp++; | |
193 | (bp-1)->m_addr = bp->m_addr; | |
194 | (bp-1)->m_size = bp->m_size; | |
195 | } | |
196 | } | |
6fb62317 | 197 | return; |
b725a0ca BJ |
198 | } |
199 | /* | |
200 | * Don't abut on the left, check for abutting on | |
201 | * the right. | |
202 | */ | |
203 | if (addr+size >= bp->m_addr && bp->m_size) { | |
204 | if (addr+size > bp->m_addr) | |
205 | goto badrmfree; | |
206 | bp->m_addr -= size; | |
207 | bp->m_size += size; | |
6fb62317 | 208 | return; |
b725a0ca BJ |
209 | } |
210 | /* | |
211 | * Don't abut at all. Make a new entry | |
212 | * and check for map overflow. | |
213 | */ | |
214 | do { | |
215 | t = bp->m_addr; | |
216 | bp->m_addr = addr; | |
217 | addr = t; | |
218 | t = bp->m_size; | |
219 | bp->m_size = size; | |
220 | bp++; | |
221 | } while (size = t); | |
222 | /* | |
223 | * Segment at bp is to be the delimiter; | |
224 | * If there is not room for it | |
225 | * then the table is too full | |
226 | * and we must discard something. | |
227 | */ | |
228 | if (bp+1 > mp->m_limit) { | |
229 | /* | |
230 | * Back bp up to last available segment. | |
231 | * which contains a segment already and must | |
232 | * be made into the delimiter. | |
233 | * Discard second to last entry, | |
234 | * since it is presumably smaller than the last | |
235 | * and move the last entry back one. | |
236 | */ | |
237 | bp--; | |
f4c13170 | 238 | printf("%s: rmap ovflo, lost [%d,%d)\n", mp->m_name, |
b725a0ca BJ |
239 | (bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size); |
240 | bp[-1] = bp[0]; | |
241 | bp[0].m_size = bp[0].m_addr = 0; | |
2694e78a | 242 | } |
b725a0ca BJ |
243 | return; |
244 | badrmfree: | |
245 | panic("bad rmfree"); | |
2694e78a | 246 | } |