| 1 | /* |
| 2 | * Copyright (c) 1982, 1986 Regents of the University of California. |
| 3 | * All rights reserved. The Berkeley software License Agreement |
| 4 | * specifies the terms and conditions for redistribution. |
| 5 | * |
| 6 | * @(#)subr_rmap.c.sav 7.2 (Berkeley) %G% |
| 7 | */ |
| 8 | |
| 9 | #include "param.h" |
| 10 | #include "systm.h" |
| 11 | #include "map.h" |
| 12 | #include "dir.h" |
| 13 | #include "user.h" |
| 14 | #include "proc.h" |
| 15 | #include "text.h" |
| 16 | #include "kernel.h" |
| 17 | |
| 18 | /* |
| 19 | * Resource map handling routines. |
| 20 | * |
| 21 | * A resource map is an array of structures each |
| 22 | * of which describes a segment of the address space of an available |
| 23 | * resource. The segments are described by their base address and |
| 24 | * length, and sorted in address order. Each resource map has a fixed |
| 25 | * maximum number of segments allowed. Resources are allocated |
| 26 | * by taking part or all of one of the segments of the map. |
| 27 | * |
| 28 | * Returning of resources will require another segment if |
| 29 | * the returned resources are not adjacent in the address |
| 30 | * space to an existing segment. If the return of a segment |
| 31 | * would require a slot which is not available, then one of |
| 32 | * the resource map segments is discarded after a warning is printed. |
| 33 | * Returning of resources may also cause the map to collapse |
| 34 | * by coalescing two existing segments and the returned space |
| 35 | * into a single segment. In this case the resource map is |
| 36 | * made smaller by copying together to fill the resultant gap. |
| 37 | * |
| 38 | * N.B.: the current implementation uses a dense array and does |
| 39 | * not admit the value ``0'' as a legal address, since that is used |
| 40 | * as a delimiter. |
| 41 | */ |
| 42 | |
| 43 | /* |
| 44 | * Initialize map mp to have (mapsize-2) segments |
| 45 | * and to be called ``name'', which we print if |
| 46 | * the slots become so fragmented that we lose space. |
| 47 | * The map itself is initialized with size elements free |
| 48 | * starting at addr. |
| 49 | */ |
| 50 | rminit(mp, size, addr, name, mapsize) |
| 51 | register struct map *mp; |
| 52 | long size, addr; |
| 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; |
| 75 | } |
| 76 | |
| 77 | /* |
| 78 | * Allocate 'size' units from the given |
| 79 | * map. Return the base of the allocated space. |
| 80 | * In a map, the addresses are increasing and the |
| 81 | * list is terminated by a 0 size. |
| 82 | * |
| 83 | * Algorithm is first-fit. |
| 84 | * |
| 85 | * This routine knows about the interleaving of the swapmap |
| 86 | * and handles that. |
| 87 | */ |
| 88 | long |
| 89 | rmalloc(mp, size) |
| 90 | register struct map *mp; |
| 91 | long size; |
| 92 | { |
| 93 | register struct mapent *ep = (struct mapent *)(mp+1); |
| 94 | register int addr; |
| 95 | register struct mapent *bp; |
| 96 | swblk_t first, rest; |
| 97 | |
| 98 | if (size <= 0 || mp == swapmap && size > dmmax) |
| 99 | panic("rmalloc"); |
| 100 | /* |
| 101 | * Search for a piece of the resource map which has enough |
| 102 | * free space to accomodate the request. |
| 103 | */ |
| 104 | for (bp = ep; bp->m_size; bp++) { |
| 105 | if (bp->m_size >= size) { |
| 106 | /* |
| 107 | * If allocating from swapmap, |
| 108 | * then have to respect interleaving |
| 109 | * boundaries. |
| 110 | */ |
| 111 | if (mp == swapmap && nswdev > 1 && |
| 112 | (first = dmmax - bp->m_addr%dmmax) < bp->m_size) { |
| 113 | if (bp->m_size - first < size) |
| 114 | continue; |
| 115 | addr = bp->m_addr + first; |
| 116 | rest = bp->m_size - first - size; |
| 117 | bp->m_size = first; |
| 118 | if (rest) |
| 119 | rmfree(swapmap, rest, addr+size); |
| 120 | return (addr); |
| 121 | } |
| 122 | /* |
| 123 | * Allocate from the map. |
| 124 | * If there is no space left of the piece |
| 125 | * we allocated from, move the rest of |
| 126 | * the pieces to the left. |
| 127 | */ |
| 128 | addr = bp->m_addr; |
| 129 | bp->m_addr += size; |
| 130 | if ((bp->m_size -= size) == 0) { |
| 131 | do { |
| 132 | bp++; |
| 133 | (bp-1)->m_addr = bp->m_addr; |
| 134 | } while ((bp-1)->m_size = bp->m_size); |
| 135 | } |
| 136 | if (mp == swapmap && addr % CLSIZE) |
| 137 | panic("rmalloc swapmap"); |
| 138 | return (addr); |
| 139 | } |
| 140 | } |
| 141 | return (0); |
| 142 | } |
| 143 | |
| 144 | /* |
| 145 | * Free the previously allocated space at addr |
| 146 | * of size units into the specified map. |
| 147 | * Sort addr into map and combine on |
| 148 | * one or both ends if possible. |
| 149 | */ |
| 150 | rmfree(mp, size, addr) |
| 151 | struct map *mp; |
| 152 | long size, addr; |
| 153 | { |
| 154 | struct mapent *firstbp; |
| 155 | register struct mapent *bp; |
| 156 | register int t; |
| 157 | |
| 158 | /* |
| 159 | * Both address and size must be |
| 160 | * positive, or the protocol has broken down. |
| 161 | */ |
| 162 | if (addr <= 0 || size <= 0) |
| 163 | goto badrmfree; |
| 164 | /* |
| 165 | * Locate the piece of the map which starts after the |
| 166 | * returned space (or the end of the map). |
| 167 | */ |
| 168 | firstbp = bp = (struct mapent *)(mp + 1); |
| 169 | for (; bp->m_addr <= addr && bp->m_size != 0; bp++) |
| 170 | continue; |
| 171 | /* |
| 172 | * If the piece on the left abuts us, |
| 173 | * then we should combine with it. |
| 174 | */ |
| 175 | if (bp > firstbp && (bp-1)->m_addr+(bp-1)->m_size >= addr) { |
| 176 | /* |
| 177 | * Check no overlap (internal error). |
| 178 | */ |
| 179 | if ((bp-1)->m_addr+(bp-1)->m_size > addr) |
| 180 | goto badrmfree; |
| 181 | /* |
| 182 | * Add into piece on the left by increasing its size. |
| 183 | */ |
| 184 | (bp-1)->m_size += size; |
| 185 | /* |
| 186 | * If the combined piece abuts the piece on |
| 187 | * the right now, compress it in also, |
| 188 | * by shifting the remaining pieces of the map over. |
| 189 | */ |
| 190 | if (bp->m_addr && addr+size >= bp->m_addr) { |
| 191 | if (addr+size > bp->m_addr) |
| 192 | goto badrmfree; |
| 193 | (bp-1)->m_size += bp->m_size; |
| 194 | while (bp->m_size) { |
| 195 | bp++; |
| 196 | (bp-1)->m_addr = bp->m_addr; |
| 197 | (bp-1)->m_size = bp->m_size; |
| 198 | } |
| 199 | } |
| 200 | goto done; |
| 201 | } |
| 202 | /* |
| 203 | * Don't abut on the left, check for abutting on |
| 204 | * the right. |
| 205 | */ |
| 206 | if (addr+size >= bp->m_addr && bp->m_size) { |
| 207 | if (addr+size > bp->m_addr) |
| 208 | goto badrmfree; |
| 209 | bp->m_addr -= size; |
| 210 | bp->m_size += size; |
| 211 | goto done; |
| 212 | } |
| 213 | /* |
| 214 | * Don't abut at all. Make a new entry |
| 215 | * and check for map overflow. |
| 216 | */ |
| 217 | do { |
| 218 | t = bp->m_addr; |
| 219 | bp->m_addr = addr; |
| 220 | addr = t; |
| 221 | t = bp->m_size; |
| 222 | bp->m_size = size; |
| 223 | bp++; |
| 224 | } while (size = t); |
| 225 | /* |
| 226 | * Segment at bp is to be the delimiter; |
| 227 | * If there is not room for it |
| 228 | * then the table is too full |
| 229 | * and we must discard something. |
| 230 | */ |
| 231 | if (bp+1 > mp->m_limit) { |
| 232 | /* |
| 233 | * Back bp up to last available segment. |
| 234 | * which contains a segment already and must |
| 235 | * be made into the delimiter. |
| 236 | * Discard second to last entry, |
| 237 | * since it is presumably smaller than the last |
| 238 | * and move the last entry back one. |
| 239 | */ |
| 240 | bp--; |
| 241 | printf("%s: rmap ovflo, lost [%d,%d)\n", mp->m_name, |
| 242 | (bp-1)->m_addr, (bp-1)->m_addr+(bp-1)->m_size); |
| 243 | bp[-1] = bp[0]; |
| 244 | bp[0].m_size = bp[0].m_addr = 0; |
| 245 | } |
| 246 | done: |
| 247 | /* |
| 248 | * THIS IS RIDICULOUS... IT DOESN'T BELONG HERE! |
| 249 | */ |
| 250 | if ((mp == kernelmap) && kmapwnt) { |
| 251 | kmapwnt = 0; |
| 252 | wakeup((caddr_t)kernelmap); |
| 253 | } |
| 254 | return; |
| 255 | badrmfree: |
| 256 | panic("bad rmfree"); |
| 257 | } |
| 258 | |
| 259 | /* |
| 260 | * Allocate 'size' units from the given map, starting at address 'addr'. |
| 261 | * Return 'addr' if successful, 0 if not. |
| 262 | * This may cause the creation or destruction of a resource map segment. |
| 263 | * |
| 264 | * This routine will return failure status if there is not enough room |
| 265 | * for a required additional map segment. |
| 266 | * |
| 267 | * An attempt to use this on 'swapmap' will result in |
| 268 | * a failure return. This is due mainly to laziness and could be fixed |
| 269 | * to do the right thing, although it probably will never be used. |
| 270 | */ |
| 271 | rmget(mp, size, addr) |
| 272 | register struct map *mp; |
| 273 | { |
| 274 | register struct mapent *ep = (struct mapent *)(mp+1); |
| 275 | register struct mapent *bp, *bp2; |
| 276 | |
| 277 | if (size <= 0) |
| 278 | panic("rmget"); |
| 279 | if (mp == swapmap) |
| 280 | return (0); |
| 281 | /* |
| 282 | * Look for a map segment containing the requested address. |
| 283 | * If none found, return failure. |
| 284 | */ |
| 285 | for (bp = ep; bp->m_size; bp++) |
| 286 | if (bp->m_addr <= addr && bp->m_addr + bp->m_size > addr) |
| 287 | break; |
| 288 | if (bp->m_size == 0) |
| 289 | return (0); |
| 290 | |
| 291 | /* |
| 292 | * If segment is too small, return failure. |
| 293 | * If big enough, allocate the block, compressing or expanding |
| 294 | * the map as necessary. |
| 295 | */ |
| 296 | if (bp->m_addr + bp->m_size < addr + size) |
| 297 | return (0); |
| 298 | if (bp->m_addr == addr) |
| 299 | if (bp->m_addr + bp->m_size == addr + size) { |
| 300 | /* |
| 301 | * Allocate entire segment and compress map |
| 302 | */ |
| 303 | bp2 = bp; |
| 304 | while (bp2->m_size) { |
| 305 | bp2++; |
| 306 | (bp2-1)->m_addr = bp2->m_addr; |
| 307 | (bp2-1)->m_size = bp2->m_size; |
| 308 | } |
| 309 | } else { |
| 310 | /* |
| 311 | * Allocate first part of segment |
| 312 | */ |
| 313 | bp->m_addr += size; |
| 314 | bp->m_size -= size; |
| 315 | } |
| 316 | else |
| 317 | if (bp->m_addr + bp->m_size == addr + size) { |
| 318 | /* |
| 319 | * Allocate last part of segment |
| 320 | */ |
| 321 | bp->m_size -= size; |
| 322 | } else { |
| 323 | /* |
| 324 | * Allocate from middle of segment, but only |
| 325 | * if table can be expanded. |
| 326 | */ |
| 327 | for (bp2=bp; bp2->m_size; bp2++) |
| 328 | ; |
| 329 | if (bp2 + 1 >= mp->m_limit) |
| 330 | return (0); |
| 331 | while (bp2 > bp) { |
| 332 | (bp2+1)->m_addr = bp2->m_addr; |
| 333 | (bp2+1)->m_size = bp2->m_size; |
| 334 | bp2--; |
| 335 | } |
| 336 | (bp+1)->m_addr = addr + size; |
| 337 | (bp+1)->m_size = |
| 338 | bp->m_addr + bp->m_size - (addr + size); |
| 339 | bp->m_size = addr - bp->m_addr; |
| 340 | } |
| 341 | return (addr); |
| 342 | } |