The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/lib/lmb.c

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    1 /*
    2  * Procedures for maintaining information about logical memory blocks.
    3  *
    4  * Peter Bergner, IBM Corp.     June 2001.
    5  * Copyright (C) 2001 Peter Bergner.
    6  *
    7  *      This program is free software; you can redistribute it and/or
    8  *      modify it under the terms of the GNU General Public License
    9  *      as published by the Free Software Foundation; either version
   10  *      2 of the License, or (at your option) any later version.
   11  */
   12 
   13 #include <linux/kernel.h>
   14 #include <linux/init.h>
   15 #include <linux/bitops.h>
   16 #include <linux/lmb.h>
   17 
   18 #define LMB_ALLOC_ANYWHERE      0
   19 
   20 struct lmb lmb;
   21 
   22 static int lmb_debug;
   23 
   24 static int __init early_lmb(char *p)
   25 {
   26         if (p && strstr(p, "debug"))
   27                 lmb_debug = 1;
   28         return 0;
   29 }
   30 early_param("lmb", early_lmb);
   31 
   32 static void lmb_dump(struct lmb_region *region, char *name)
   33 {
   34         unsigned long long base, size;
   35         int i;
   36 
   37         pr_info(" %s.cnt  = 0x%lx\n", name, region->cnt);
   38 
   39         for (i = 0; i < region->cnt; i++) {
   40                 base = region->region[i].base;
   41                 size = region->region[i].size;
   42 
   43                 pr_info(" %s[0x%x]\t0x%016llx - 0x%016llx, 0x%llx bytes\n",
   44                     name, i, base, base + size - 1, size);
   45         }
   46 }
   47 
   48 void lmb_dump_all(void)
   49 {
   50         if (!lmb_debug)
   51                 return;
   52 
   53         pr_info("LMB configuration:\n");
   54         pr_info(" rmo_size    = 0x%llx\n", (unsigned long long)lmb.rmo_size);
   55         pr_info(" memory.size = 0x%llx\n", (unsigned long long)lmb.memory.size);
   56 
   57         lmb_dump(&lmb.memory, "memory");
   58         lmb_dump(&lmb.reserved, "reserved");
   59 }
   60 
   61 static unsigned long lmb_addrs_overlap(u64 base1, u64 size1, u64 base2,
   62                                         u64 size2)
   63 {
   64         return ((base1 < (base2 + size2)) && (base2 < (base1 + size1)));
   65 }
   66 
   67 static long lmb_addrs_adjacent(u64 base1, u64 size1, u64 base2, u64 size2)
   68 {
   69         if (base2 == base1 + size1)
   70                 return 1;
   71         else if (base1 == base2 + size2)
   72                 return -1;
   73 
   74         return 0;
   75 }
   76 
   77 static long lmb_regions_adjacent(struct lmb_region *rgn,
   78                 unsigned long r1, unsigned long r2)
   79 {
   80         u64 base1 = rgn->region[r1].base;
   81         u64 size1 = rgn->region[r1].size;
   82         u64 base2 = rgn->region[r2].base;
   83         u64 size2 = rgn->region[r2].size;
   84 
   85         return lmb_addrs_adjacent(base1, size1, base2, size2);
   86 }
   87 
   88 static void lmb_remove_region(struct lmb_region *rgn, unsigned long r)
   89 {
   90         unsigned long i;
   91 
   92         for (i = r; i < rgn->cnt - 1; i++) {
   93                 rgn->region[i].base = rgn->region[i + 1].base;
   94                 rgn->region[i].size = rgn->region[i + 1].size;
   95         }
   96         rgn->cnt--;
   97 }
   98 
   99 /* Assumption: base addr of region 1 < base addr of region 2 */
  100 static void lmb_coalesce_regions(struct lmb_region *rgn,
  101                 unsigned long r1, unsigned long r2)
  102 {
  103         rgn->region[r1].size += rgn->region[r2].size;
  104         lmb_remove_region(rgn, r2);
  105 }
  106 
  107 void __init lmb_init(void)
  108 {
  109         /* Create a dummy zero size LMB which will get coalesced away later.
  110          * This simplifies the lmb_add() code below...
  111          */
  112         lmb.memory.region[0].base = 0;
  113         lmb.memory.region[0].size = 0;
  114         lmb.memory.cnt = 1;
  115 
  116         /* Ditto. */
  117         lmb.reserved.region[0].base = 0;
  118         lmb.reserved.region[0].size = 0;
  119         lmb.reserved.cnt = 1;
  120 }
  121 
  122 void __init lmb_analyze(void)
  123 {
  124         int i;
  125 
  126         lmb.memory.size = 0;
  127 
  128         for (i = 0; i < lmb.memory.cnt; i++)
  129                 lmb.memory.size += lmb.memory.region[i].size;
  130 }
  131 
  132 static long lmb_add_region(struct lmb_region *rgn, u64 base, u64 size)
  133 {
  134         unsigned long coalesced = 0;
  135         long adjacent, i;
  136 
  137         if ((rgn->cnt == 1) && (rgn->region[0].size == 0)) {
  138                 rgn->region[0].base = base;
  139                 rgn->region[0].size = size;
  140                 return 0;
  141         }
  142 
  143         /* First try and coalesce this LMB with another. */
  144         for (i = 0; i < rgn->cnt; i++) {
  145                 u64 rgnbase = rgn->region[i].base;
  146                 u64 rgnsize = rgn->region[i].size;
  147 
  148                 if ((rgnbase == base) && (rgnsize == size))
  149                         /* Already have this region, so we're done */
  150                         return 0;
  151 
  152                 adjacent = lmb_addrs_adjacent(base, size, rgnbase, rgnsize);
  153                 if (adjacent > 0) {
  154                         rgn->region[i].base -= size;
  155                         rgn->region[i].size += size;
  156                         coalesced++;
  157                         break;
  158                 } else if (adjacent < 0) {
  159                         rgn->region[i].size += size;
  160                         coalesced++;
  161                         break;
  162                 }
  163         }
  164 
  165         if ((i < rgn->cnt - 1) && lmb_regions_adjacent(rgn, i, i+1)) {
  166                 lmb_coalesce_regions(rgn, i, i+1);
  167                 coalesced++;
  168         }
  169 
  170         if (coalesced)
  171                 return coalesced;
  172         if (rgn->cnt >= MAX_LMB_REGIONS)
  173                 return -1;
  174 
  175         /* Couldn't coalesce the LMB, so add it to the sorted table. */
  176         for (i = rgn->cnt - 1; i >= 0; i--) {
  177                 if (base < rgn->region[i].base) {
  178                         rgn->region[i+1].base = rgn->region[i].base;
  179                         rgn->region[i+1].size = rgn->region[i].size;
  180                 } else {
  181                         rgn->region[i+1].base = base;
  182                         rgn->region[i+1].size = size;
  183                         break;
  184                 }
  185         }
  186 
  187         if (base < rgn->region[0].base) {
  188                 rgn->region[0].base = base;
  189                 rgn->region[0].size = size;
  190         }
  191         rgn->cnt++;
  192 
  193         return 0;
  194 }
  195 
  196 long lmb_add(u64 base, u64 size)
  197 {
  198         struct lmb_region *_rgn = &lmb.memory;
  199 
  200         /* On pSeries LPAR systems, the first LMB is our RMO region. */
  201         if (base == 0)
  202                 lmb.rmo_size = size;
  203 
  204         return lmb_add_region(_rgn, base, size);
  205 
  206 }
  207 
  208 long lmb_remove(u64 base, u64 size)
  209 {
  210         struct lmb_region *rgn = &(lmb.memory);
  211         u64 rgnbegin, rgnend;
  212         u64 end = base + size;
  213         int i;
  214 
  215         rgnbegin = rgnend = 0; /* supress gcc warnings */
  216 
  217         /* Find the region where (base, size) belongs to */
  218         for (i=0; i < rgn->cnt; i++) {
  219                 rgnbegin = rgn->region[i].base;
  220                 rgnend = rgnbegin + rgn->region[i].size;
  221 
  222                 if ((rgnbegin <= base) && (end <= rgnend))
  223                         break;
  224         }
  225 
  226         /* Didn't find the region */
  227         if (i == rgn->cnt)
  228                 return -1;
  229 
  230         /* Check to see if we are removing entire region */
  231         if ((rgnbegin == base) && (rgnend == end)) {
  232                 lmb_remove_region(rgn, i);
  233                 return 0;
  234         }
  235 
  236         /* Check to see if region is matching at the front */
  237         if (rgnbegin == base) {
  238                 rgn->region[i].base = end;
  239                 rgn->region[i].size -= size;
  240                 return 0;
  241         }
  242 
  243         /* Check to see if the region is matching at the end */
  244         if (rgnend == end) {
  245                 rgn->region[i].size -= size;
  246                 return 0;
  247         }
  248 
  249         /*
  250          * We need to split the entry -  adjust the current one to the
  251          * beginging of the hole and add the region after hole.
  252          */
  253         rgn->region[i].size = base - rgn->region[i].base;
  254         return lmb_add_region(rgn, end, rgnend - end);
  255 }
  256 
  257 long __init lmb_reserve(u64 base, u64 size)
  258 {
  259         struct lmb_region *_rgn = &lmb.reserved;
  260 
  261         BUG_ON(0 == size);
  262 
  263         return lmb_add_region(_rgn, base, size);
  264 }
  265 
  266 long __init lmb_overlaps_region(struct lmb_region *rgn, u64 base, u64 size)
  267 {
  268         unsigned long i;
  269 
  270         for (i = 0; i < rgn->cnt; i++) {
  271                 u64 rgnbase = rgn->region[i].base;
  272                 u64 rgnsize = rgn->region[i].size;
  273                 if (lmb_addrs_overlap(base, size, rgnbase, rgnsize))
  274                         break;
  275         }
  276 
  277         return (i < rgn->cnt) ? i : -1;
  278 }
  279 
  280 static u64 lmb_align_down(u64 addr, u64 size)
  281 {
  282         return addr & ~(size - 1);
  283 }
  284 
  285 static u64 lmb_align_up(u64 addr, u64 size)
  286 {
  287         return (addr + (size - 1)) & ~(size - 1);
  288 }
  289 
  290 static u64 __init lmb_alloc_nid_unreserved(u64 start, u64 end,
  291                                            u64 size, u64 align)
  292 {
  293         u64 base, res_base;
  294         long j;
  295 
  296         base = lmb_align_down((end - size), align);
  297         while (start <= base) {
  298                 j = lmb_overlaps_region(&lmb.reserved, base, size);
  299                 if (j < 0) {
  300                         /* this area isn't reserved, take it */
  301                         if (lmb_add_region(&lmb.reserved, base, size) < 0)
  302                                 base = ~(u64)0;
  303                         return base;
  304                 }
  305                 res_base = lmb.reserved.region[j].base;
  306                 if (res_base < size)
  307                         break;
  308                 base = lmb_align_down(res_base - size, align);
  309         }
  310 
  311         return ~(u64)0;
  312 }
  313 
  314 static u64 __init lmb_alloc_nid_region(struct lmb_property *mp,
  315                                        u64 (*nid_range)(u64, u64, int *),
  316                                        u64 size, u64 align, int nid)
  317 {
  318         u64 start, end;
  319 
  320         start = mp->base;
  321         end = start + mp->size;
  322 
  323         start = lmb_align_up(start, align);
  324         while (start < end) {
  325                 u64 this_end;
  326                 int this_nid;
  327 
  328                 this_end = nid_range(start, end, &this_nid);
  329                 if (this_nid == nid) {
  330                         u64 ret = lmb_alloc_nid_unreserved(start, this_end,
  331                                                            size, align);
  332                         if (ret != ~(u64)0)
  333                                 return ret;
  334                 }
  335                 start = this_end;
  336         }
  337 
  338         return ~(u64)0;
  339 }
  340 
  341 u64 __init lmb_alloc_nid(u64 size, u64 align, int nid,
  342                          u64 (*nid_range)(u64 start, u64 end, int *nid))
  343 {
  344         struct lmb_region *mem = &lmb.memory;
  345         int i;
  346 
  347         BUG_ON(0 == size);
  348 
  349         size = lmb_align_up(size, align);
  350 
  351         for (i = 0; i < mem->cnt; i++) {
  352                 u64 ret = lmb_alloc_nid_region(&mem->region[i],
  353                                                nid_range,
  354                                                size, align, nid);
  355                 if (ret != ~(u64)0)
  356                         return ret;
  357         }
  358 
  359         return lmb_alloc(size, align);
  360 }
  361 
  362 u64 __init lmb_alloc(u64 size, u64 align)
  363 {
  364         return lmb_alloc_base(size, align, LMB_ALLOC_ANYWHERE);
  365 }
  366 
  367 u64 __init lmb_alloc_base(u64 size, u64 align, u64 max_addr)
  368 {
  369         u64 alloc;
  370 
  371         alloc = __lmb_alloc_base(size, align, max_addr);
  372 
  373         if (alloc == 0)
  374                 panic("ERROR: Failed to allocate 0x%llx bytes below 0x%llx.\n",
  375                       (unsigned long long) size, (unsigned long long) max_addr);
  376 
  377         return alloc;
  378 }
  379 
  380 u64 __init __lmb_alloc_base(u64 size, u64 align, u64 max_addr)
  381 {
  382         long i, j;
  383         u64 base = 0;
  384         u64 res_base;
  385 
  386         BUG_ON(0 == size);
  387 
  388         size = lmb_align_up(size, align);
  389 
  390         /* On some platforms, make sure we allocate lowmem */
  391         /* Note that LMB_REAL_LIMIT may be LMB_ALLOC_ANYWHERE */
  392         if (max_addr == LMB_ALLOC_ANYWHERE)
  393                 max_addr = LMB_REAL_LIMIT;
  394 
  395         for (i = lmb.memory.cnt - 1; i >= 0; i--) {
  396                 u64 lmbbase = lmb.memory.region[i].base;
  397                 u64 lmbsize = lmb.memory.region[i].size;
  398 
  399                 if (lmbsize < size)
  400                         continue;
  401                 if (max_addr == LMB_ALLOC_ANYWHERE)
  402                         base = lmb_align_down(lmbbase + lmbsize - size, align);
  403                 else if (lmbbase < max_addr) {
  404                         base = min(lmbbase + lmbsize, max_addr);
  405                         base = lmb_align_down(base - size, align);
  406                 } else
  407                         continue;
  408 
  409                 while (base && lmbbase <= base) {
  410                         j = lmb_overlaps_region(&lmb.reserved, base, size);
  411                         if (j < 0) {
  412                                 /* this area isn't reserved, take it */
  413                                 if (lmb_add_region(&lmb.reserved, base, size) < 0)
  414                                         return 0;
  415                                 return base;
  416                         }
  417                         res_base = lmb.reserved.region[j].base;
  418                         if (res_base < size)
  419                                 break;
  420                         base = lmb_align_down(res_base - size, align);
  421                 }
  422         }
  423         return 0;
  424 }
  425 
  426 /* You must call lmb_analyze() before this. */
  427 u64 __init lmb_phys_mem_size(void)
  428 {
  429         return lmb.memory.size;
  430 }
  431 
  432 u64 lmb_end_of_DRAM(void)
  433 {
  434         int idx = lmb.memory.cnt - 1;
  435 
  436         return (lmb.memory.region[idx].base + lmb.memory.region[idx].size);
  437 }
  438 
  439 /* You must call lmb_analyze() after this. */
  440 void __init lmb_enforce_memory_limit(u64 memory_limit)
  441 {
  442         unsigned long i;
  443         u64 limit;
  444         struct lmb_property *p;
  445 
  446         if (!memory_limit)
  447                 return;
  448 
  449         /* Truncate the lmb regions to satisfy the memory limit. */
  450         limit = memory_limit;
  451         for (i = 0; i < lmb.memory.cnt; i++) {
  452                 if (limit > lmb.memory.region[i].size) {
  453                         limit -= lmb.memory.region[i].size;
  454                         continue;
  455                 }
  456 
  457                 lmb.memory.region[i].size = limit;
  458                 lmb.memory.cnt = i + 1;
  459                 break;
  460         }
  461 
  462         if (lmb.memory.region[0].size < lmb.rmo_size)
  463                 lmb.rmo_size = lmb.memory.region[0].size;
  464 
  465         memory_limit = lmb_end_of_DRAM();
  466 
  467         /* And truncate any reserves above the limit also. */
  468         for (i = 0; i < lmb.reserved.cnt; i++) {
  469                 p = &lmb.reserved.region[i];
  470 
  471                 if (p->base > memory_limit)
  472                         p->size = 0;
  473                 else if ((p->base + p->size) > memory_limit)
  474                         p->size = memory_limit - p->base;
  475 
  476                 if (p->size == 0) {
  477                         lmb_remove_region(&lmb.reserved, i);
  478                         i--;
  479                 }
  480         }
  481 }
  482 
  483 int __init lmb_is_reserved(u64 addr)
  484 {
  485         int i;
  486 
  487         for (i = 0; i < lmb.reserved.cnt; i++) {
  488                 u64 upper = lmb.reserved.region[i].base +
  489                         lmb.reserved.region[i].size - 1;
  490                 if ((addr >= lmb.reserved.region[i].base) && (addr <= upper))
  491                         return 1;
  492         }
  493         return 0;
  494 }
  495 
  496 /*
  497  * Given a <base, len>, find which memory regions belong to this range.
  498  * Adjust the request and return a contiguous chunk.
  499  */
  500 int lmb_find(struct lmb_property *res)
  501 {
  502         int i;
  503         u64 rstart, rend;
  504 
  505         rstart = res->base;
  506         rend = rstart + res->size - 1;
  507 
  508         for (i = 0; i < lmb.memory.cnt; i++) {
  509                 u64 start = lmb.memory.region[i].base;
  510                 u64 end = start + lmb.memory.region[i].size - 1;
  511 
  512                 if (start > rend)
  513                         return -1;
  514 
  515                 if ((end >= rstart) && (start < rend)) {
  516                         /* adjust the request */
  517                         if (rstart < start)
  518                                 rstart = start;
  519                         if (rend > end)
  520                                 rend = end;
  521                         res->base = rstart;
  522                         res->size = rend - rstart + 1;
  523                         return 0;
  524                 }
  525         }
  526         return -1;
  527 }

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