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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 | * |
38a01dbe | 7 | * @(#)subr_rmap.c 7.11 (Berkeley) %G% |
da7c5cc6 | 8 | */ |
2694e78a | 9 | |
38a01dbe KB |
10 | #include <sys/param.h> |
11 | #include <sys/systm.h> | |
12 | #include <sys/map.h> | |
13 | #include <sys/dmap.h> /* XXX */ | |
14 | #include <sys/proc.h> | |
15 | #include <sys/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 | */ | |
205550fe | 49 | void |
b725a0ca BJ |
50 | rminit(mp, size, addr, name, mapsize) |
51 | register struct map *mp; | |
a29f7995 | 52 | long size, addr; |
b725a0ca BJ |
53 | char *name; |
54 | int mapsize; | |
55 | { | |
56 | register struct mapent *ep = (struct mapent *)(mp+1); | |
57 | ||
58 | mp->m_name = name; | |
59 | /* N.B.: WE ASSUME HERE THAT sizeof (struct map) == sizeof (struct mapent) */ | |
60 | /* | |
61 | * One of the mapsize slots is taken by the map structure, | |
62 | * segments has size 0 and addr 0, and acts as a delimiter. | |
63 | * We insure that we never use segments past the end of | |
64 | * the array which is given by mp->m_limit. | |
65 | * Instead, when excess segments occur we discard some resources. | |
66 | */ | |
67 | mp->m_limit = (struct mapent *)&mp[mapsize]; | |
68 | /* | |
69 | * Simulate a rmfree(), but with the option to | |
70 | * call with size 0 and addr 0 when we just want | |
71 | * to initialize without freeing. | |
72 | */ | |
73 | ep->m_size = size; | |
74 | ep->m_addr = addr; | |
92d92331 MK |
75 | (++ep)->m_size = 0; |
76 | ep->m_addr = 0; | |
b725a0ca BJ |
77 | } |
78 | ||
2694e78a | 79 | /* |
4e3656e7 KM |
80 | * A piece of memory of at least size units is allocated from the |
81 | * specified map using a first-fit algorithm. It returns the starting | |
82 | * address of the allocated space. | |
b725a0ca | 83 | * |
4e3656e7 | 84 | * This routine knows about and handles the interleaving of the swapmap. |
2694e78a | 85 | */ |
39d536e6 | 86 | long |
b725a0ca BJ |
87 | rmalloc(mp, size) |
88 | register struct map *mp; | |
39d536e6 | 89 | long size; |
2694e78a | 90 | { |
b725a0ca BJ |
91 | register struct mapent *ep = (struct mapent *)(mp+1); |
92 | register int addr; | |
93 | register struct mapent *bp; | |
41888f16 | 94 | swblk_t first, rest; |
2694e78a | 95 | |
d668d9ba | 96 | if (size <= 0 || mp == swapmap && size > dmmax) |
b725a0ca BJ |
97 | panic("rmalloc"); |
98 | /* | |
99 | * Search for a piece of the resource map which has enough | |
100 | * free space to accomodate the request. | |
101 | */ | |
102 | for (bp = ep; bp->m_size; bp++) { | |
2694e78a | 103 | if (bp->m_size >= size) { |
b725a0ca BJ |
104 | /* |
105 | * If allocating from swapmap, | |
106 | * then have to respect interleaving | |
107 | * boundaries. | |
108 | */ | |
d668d9ba | 109 | if (mp == swapmap && nswdev > 1 && |
c1954620 | 110 | (first = dmmax - bp->m_addr%dmmax) < size) { |
41888f16 BJ |
111 | if (bp->m_size - first < size) |
112 | continue; | |
b725a0ca | 113 | addr = bp->m_addr + first; |
41888f16 BJ |
114 | rest = bp->m_size - first - size; |
115 | bp->m_size = first; | |
116 | if (rest) | |
b725a0ca BJ |
117 | rmfree(swapmap, rest, addr+size); |
118 | return (addr); | |
41888f16 | 119 | } |
b725a0ca BJ |
120 | /* |
121 | * Allocate from the map. | |
122 | * If there is no space left of the piece | |
123 | * we allocated from, move the rest of | |
124 | * the pieces to the left. | |
125 | */ | |
126 | addr = bp->m_addr; | |
2694e78a BJ |
127 | bp->m_addr += size; |
128 | if ((bp->m_size -= size) == 0) { | |
129 | do { | |
130 | bp++; | |
131 | (bp-1)->m_addr = bp->m_addr; | |
132 | } while ((bp-1)->m_size = bp->m_size); | |
133 | } | |
b725a0ca BJ |
134 | if (mp == swapmap && addr % CLSIZE) |
135 | panic("rmalloc swapmap"); | |
136 | return (addr); | |
2694e78a BJ |
137 | } |
138 | } | |
b725a0ca | 139 | return (0); |
2694e78a BJ |
140 | } |
141 | ||
142 | /* | |
4e3656e7 KM |
143 | * The previously allocated space at addr of size units is freed |
144 | * into the specified map. This routine is responsible for sorting | |
145 | * the frred space into the correct location in the map, and coalescing | |
146 | * it with free space on either side if they adjoin. | |
2694e78a | 147 | */ |
205550fe | 148 | void |
b725a0ca BJ |
149 | rmfree(mp, size, addr) |
150 | struct map *mp; | |
39d536e6 | 151 | long size, addr; |
2694e78a | 152 | { |
b725a0ca BJ |
153 | struct mapent *firstbp; |
154 | register struct mapent *bp; | |
2694e78a BJ |
155 | register int t; |
156 | ||
b725a0ca BJ |
157 | /* |
158 | * Both address and size must be | |
159 | * positive, or the protocol has broken down. | |
160 | */ | |
161 | if (addr <= 0 || size <= 0) | |
162 | goto badrmfree; | |
163 | /* | |
164 | * Locate the piece of the map which starts after the | |
165 | * returned space (or the end of the map). | |
166 | */ | |
167 | firstbp = bp = (struct mapent *)(mp + 1); | |
168 | for (; bp->m_addr <= addr && bp->m_size != 0; bp++) | |
2694e78a | 169 | continue; |
b725a0ca BJ |
170 | /* |
171 | * If the piece on the left abuts us, | |
172 | * then we should combine with it. | |
173 | */ | |
174 | if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) { | |
175 | /* | |
176 | * Check no overlap (internal error). | |
177 | */ | |
178 | if ((bp-1)->m_addr+(bp-1)->m_size > addr) | |
179 | goto badrmfree; | |
180 | /* | |
181 | * Add into piece on the left by increasing its size. | |
182 | */ | |
2694e78a | 183 | (bp-1)->m_size += size; |
b725a0ca BJ |
184 | /* |
185 | * If the combined piece abuts the piece on | |
186 | * the right now, compress it in also, | |
187 | * by shifting the remaining pieces of the map over. | |
188 | */ | |
189 | if (bp->m_addr && addr+size >= bp->m_addr) { | |
190 | if (addr+size > bp->m_addr) | |
191 | goto badrmfree; | |
2694e78a BJ |
192 | (bp-1)->m_size += bp->m_size; |
193 | while (bp->m_size) { | |
194 | bp++; | |
195 | (bp-1)->m_addr = bp->m_addr; | |
196 | (bp-1)->m_size = bp->m_size; | |
197 | } | |
198 | } | |
6fb62317 | 199 | return; |
b725a0ca BJ |
200 | } |
201 | /* | |
202 | * Don't abut on the left, check for abutting on | |
203 | * the right. | |
204 | */ | |
205 | if (addr+size >= bp->m_addr && bp->m_size) { | |
206 | if (addr+size > bp->m_addr) | |
207 | goto badrmfree; | |
208 | bp->m_addr -= size; | |
209 | bp->m_size += size; | |
6fb62317 | 210 | return; |
b725a0ca BJ |
211 | } |
212 | /* | |
213 | * Don't abut at all. Make a new entry | |
214 | * and check for map overflow. | |
215 | */ | |
216 | do { | |
217 | t = bp->m_addr; | |
218 | bp->m_addr = addr; | |
219 | addr = t; | |
220 | t = bp->m_size; | |
221 | bp->m_size = size; | |
222 | bp++; | |
223 | } while (size = t); | |
224 | /* | |
225 | * Segment at bp is to be the delimiter; | |
226 | * If there is not room for it | |
227 | * then the table is too full | |
228 | * and we must discard something. | |
229 | */ | |
230 | if (bp+1 > mp->m_limit) { | |
231 | /* | |
232 | * Back bp up to last available segment. | |
233 | * which contains a segment already and must | |
234 | * be made into the delimiter. | |
235 | * Discard second to last entry, | |
236 | * since it is presumably smaller than the last | |
237 | * and move the last entry back one. | |
238 | */ | |
239 | bp--; | |
f4c13170 | 240 | printf("%s: rmap ovflo, lost [%d,%d)\n", mp->m_name, |
b725a0ca BJ |
241 | (bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size); |
242 | bp[-1] = bp[0]; | |
243 | bp[0].m_size = bp[0].m_addr = 0; | |
2694e78a | 244 | } |
b725a0ca BJ |
245 | return; |
246 | badrmfree: | |
247 | panic("bad rmfree"); | |
2694e78a | 248 | } |