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964bcfb1 | 1 | /* subr_rmap.c 4.4 81/03/09 */ |
2694e78a BJ |
2 | |
3 | #include "../h/param.h" | |
4 | #include "../h/systm.h" | |
5 | #include "../h/map.h" | |
6 | #include "../h/dir.h" | |
7 | #include "../h/user.h" | |
8 | #include "../h/proc.h" | |
9 | #include "../h/mtpr.h" | |
10 | #include "../h/text.h" | |
11 | ||
b725a0ca BJ |
12 | /* |
13 | * Resource map handling routines. | |
14 | * | |
15 | * A resource map is an array of structures each | |
16 | * of which describes a segment of the address space of an available | |
17 | * resource. The segments are described by their base address and | |
18 | * length, and sorted in address order. Each resource map has a fixed | |
19 | * maximum number of segments allowed. Resources are allocated | |
20 | * by taking part or all of one of the segments of the map. | |
21 | * | |
22 | * Returning of resources will require another segment if | |
23 | * the returned resources are not adjacent in the address | |
24 | * space to an existing segment. If the return of a segment | |
25 | * would require a slot which is not available, then one of | |
26 | * the resource map segments is discarded after a warning is printed. | |
27 | * Returning of resources may also cause the map to collapse | |
28 | * by coalescing two existing segments and the returned space | |
29 | * into a single segment. In this case the resource map is | |
30 | * made smaller by copying together to fill the resultant gap. | |
31 | * | |
32 | * N.B.: the current implementation uses a dense array and does | |
33 | * not admit the value ``0'' as a legal address, since that is used | |
34 | * as a delimiter. | |
35 | */ | |
36 | ||
37 | /* | |
38 | * Initialize map mp to have (mapsize-2) segments | |
39 | * and to be called ``name'', which we print if | |
40 | * the slots become so fragmented that we lose space. | |
41 | * The map itself is initialized with size elements free | |
42 | * starting at addr. | |
43 | */ | |
44 | rminit(mp, size, addr, name, mapsize) | |
45 | register struct map *mp; | |
46 | int size, addr; | |
47 | char *name; | |
48 | int mapsize; | |
49 | { | |
50 | register struct mapent *ep = (struct mapent *)(mp+1); | |
51 | ||
52 | mp->m_name = name; | |
53 | /* N.B.: WE ASSUME HERE THAT sizeof (struct map) == sizeof (struct mapent) */ | |
54 | /* | |
55 | * One of the mapsize slots is taken by the map structure, | |
56 | * segments has size 0 and addr 0, and acts as a delimiter. | |
57 | * We insure that we never use segments past the end of | |
58 | * the array which is given by mp->m_limit. | |
59 | * Instead, when excess segments occur we discard some resources. | |
60 | */ | |
61 | mp->m_limit = (struct mapent *)&mp[mapsize]; | |
62 | /* | |
63 | * Simulate a rmfree(), but with the option to | |
64 | * call with size 0 and addr 0 when we just want | |
65 | * to initialize without freeing. | |
66 | */ | |
67 | ep->m_size = size; | |
68 | ep->m_addr = addr; | |
69 | } | |
70 | ||
2694e78a BJ |
71 | /* |
72 | * Allocate 'size' units from the given | |
b725a0ca | 73 | * map. Return the base of the allocated space. |
2694e78a BJ |
74 | * In a map, the addresses are increasing and the |
75 | * list is terminated by a 0 size. | |
b725a0ca | 76 | * |
2694e78a | 77 | * Algorithm is first-fit. |
b725a0ca BJ |
78 | * |
79 | * This routine knows about the interleaving of the swapmap | |
80 | * and handles that. | |
2694e78a | 81 | */ |
b725a0ca BJ |
82 | rmalloc(mp, size) |
83 | register struct map *mp; | |
2694e78a | 84 | { |
b725a0ca BJ |
85 | register struct mapent *ep = (struct mapent *)(mp+1); |
86 | register int addr; | |
87 | register struct mapent *bp; | |
41888f16 | 88 | swblk_t first, rest; |
2694e78a | 89 | |
41888f16 | 90 | if (size <= 0 || mp == swapmap && size > DMMAX) |
b725a0ca BJ |
91 | panic("rmalloc"); |
92 | /* | |
93 | * Search for a piece of the resource map which has enough | |
94 | * free space to accomodate the request. | |
95 | */ | |
96 | for (bp = ep; bp->m_size; bp++) { | |
2694e78a | 97 | if (bp->m_size >= size) { |
b725a0ca BJ |
98 | /* |
99 | * If allocating from swapmap, | |
100 | * then have to respect interleaving | |
101 | * boundaries. | |
102 | */ | |
41888f16 BJ |
103 | if (mp == swapmap && |
104 | (first = DMMAX - bp->m_addr%DMMAX) < bp->m_size) { | |
105 | if (bp->m_size - first < size) | |
106 | continue; | |
b725a0ca | 107 | addr = bp->m_addr + first; |
41888f16 BJ |
108 | rest = bp->m_size - first - size; |
109 | bp->m_size = first; | |
110 | if (rest) | |
b725a0ca BJ |
111 | rmfree(swapmap, rest, addr+size); |
112 | return (addr); | |
41888f16 | 113 | } |
b725a0ca BJ |
114 | /* |
115 | * Allocate from the map. | |
116 | * If there is no space left of the piece | |
117 | * we allocated from, move the rest of | |
118 | * the pieces to the left. | |
119 | */ | |
120 | addr = bp->m_addr; | |
2694e78a BJ |
121 | bp->m_addr += size; |
122 | if ((bp->m_size -= size) == 0) { | |
123 | do { | |
124 | bp++; | |
125 | (bp-1)->m_addr = bp->m_addr; | |
126 | } while ((bp-1)->m_size = bp->m_size); | |
127 | } | |
b725a0ca BJ |
128 | if (mp == swapmap && addr % CLSIZE) |
129 | panic("rmalloc swapmap"); | |
130 | return (addr); | |
2694e78a BJ |
131 | } |
132 | } | |
b725a0ca | 133 | return (0); |
2694e78a BJ |
134 | } |
135 | ||
136 | /* | |
b725a0ca | 137 | * Free the previously allocated space at addr |
2694e78a | 138 | * of size units into the specified map. |
b725a0ca | 139 | * Sort addr into map and combine on |
2694e78a BJ |
140 | * one or both ends if possible. |
141 | */ | |
b725a0ca BJ |
142 | rmfree(mp, size, addr) |
143 | struct map *mp; | |
144 | register int size, addr; | |
2694e78a | 145 | { |
b725a0ca BJ |
146 | struct mapent *firstbp; |
147 | register struct mapent *bp; | |
2694e78a BJ |
148 | register int t; |
149 | ||
b725a0ca BJ |
150 | /* |
151 | * Both address and size must be | |
152 | * positive, or the protocol has broken down. | |
153 | */ | |
154 | if (addr <= 0 || size <= 0) | |
155 | goto badrmfree; | |
156 | /* | |
157 | * Locate the piece of the map which starts after the | |
158 | * returned space (or the end of the map). | |
159 | */ | |
160 | firstbp = bp = (struct mapent *)(mp + 1); | |
161 | for (; bp->m_addr <= addr && bp->m_size != 0; bp++) | |
2694e78a | 162 | continue; |
b725a0ca BJ |
163 | /* |
164 | * If the piece on the left abuts us, | |
165 | * then we should combine with it. | |
166 | */ | |
167 | if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) { | |
168 | /* | |
169 | * Check no overlap (internal error). | |
170 | */ | |
171 | if ((bp-1)->m_addr+(bp-1)->m_size > addr) | |
172 | goto badrmfree; | |
173 | /* | |
174 | * Add into piece on the left by increasing its size. | |
175 | */ | |
2694e78a | 176 | (bp-1)->m_size += size; |
b725a0ca BJ |
177 | /* |
178 | * If the combined piece abuts the piece on | |
179 | * the right now, compress it in also, | |
180 | * by shifting the remaining pieces of the map over. | |
181 | */ | |
182 | if (bp->m_addr && addr+size >= bp->m_addr) { | |
183 | if (addr+size > bp->m_addr) | |
184 | goto badrmfree; | |
2694e78a BJ |
185 | (bp-1)->m_size += bp->m_size; |
186 | while (bp->m_size) { | |
187 | bp++; | |
188 | (bp-1)->m_addr = bp->m_addr; | |
189 | (bp-1)->m_size = bp->m_size; | |
190 | } | |
191 | } | |
b725a0ca BJ |
192 | goto done; |
193 | } | |
194 | /* | |
195 | * Don't abut on the left, check for abutting on | |
196 | * the right. | |
197 | */ | |
198 | if (addr+size >= bp->m_addr && bp->m_size) { | |
199 | if (addr+size > bp->m_addr) | |
200 | goto badrmfree; | |
201 | bp->m_addr -= size; | |
202 | bp->m_size += size; | |
203 | goto done; | |
204 | } | |
205 | /* | |
206 | * Don't abut at all. Make a new entry | |
207 | * and check for map overflow. | |
208 | */ | |
209 | do { | |
210 | t = bp->m_addr; | |
211 | bp->m_addr = addr; | |
212 | addr = t; | |
213 | t = bp->m_size; | |
214 | bp->m_size = size; | |
215 | bp++; | |
216 | } while (size = t); | |
217 | /* | |
218 | * Segment at bp is to be the delimiter; | |
219 | * If there is not room for it | |
220 | * then the table is too full | |
221 | * and we must discard something. | |
222 | */ | |
223 | if (bp+1 > mp->m_limit) { | |
224 | /* | |
225 | * Back bp up to last available segment. | |
226 | * which contains a segment already and must | |
227 | * be made into the delimiter. | |
228 | * Discard second to last entry, | |
229 | * since it is presumably smaller than the last | |
230 | * and move the last entry back one. | |
231 | */ | |
232 | bp--; | |
f4c13170 | 233 | printf("%s: rmap ovflo, lost [%d,%d)\n", mp->m_name, |
b725a0ca BJ |
234 | (bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size); |
235 | bp[-1] = bp[0]; | |
236 | bp[0].m_size = bp[0].m_addr = 0; | |
2694e78a | 237 | } |
b725a0ca BJ |
238 | done: |
239 | /* | |
240 | * THIS IS RIDICULOUS... IT DOESN'T BELONG HERE! | |
241 | */ | |
2694e78a BJ |
242 | if ((mp == kernelmap) && kmapwnt) { |
243 | kmapwnt = 0; | |
244 | wakeup((caddr_t)kernelmap); | |
245 | } | |
b725a0ca BJ |
246 | return; |
247 | badrmfree: | |
248 | panic("bad rmfree"); | |
2694e78a | 249 | } |