kernel2/swap.c

   1 /*
   2     meinOS - A unix-like x86 microkernel operating system
   3     Copyright (C) 2008  Janosch Gräf <janosch.graef@gmx.net>
   4
   5     This program is free software: you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation, either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19 #include <procm.h>
  20 #include <paging.h>
  21 #include <memphys.h>
  22 #include <memuser.h>
  23 #include <swap.h>
  24 #include <malloc.h>
  25 #include <syscall.h>
  26
  27 /**
  28  * Initializes swapping
  29  *  @return Success?
  30  */
  31 int swap_init() {
  32   swap_proc = NULL;
  33   //if (syscall_create(SYSCALL_SWAP_ENABLE,swap_enable,1)==-1) return -1;
  34   return 0;
  35 }
  36
  37 /**
  38  * Enables swapping (Syscall)
  39  *  @return Success?
  40  */
  41 int swap_enable(void *buf) {
  42   if (swap_proc!=NULL) return -1;
  43   swap_queue = llist_create();
  44   swap_proc = proc_current;
  45   swap_buf = buf;
  46   return 0;
  47 }
  48
  49 /**
  50  * Calls a swap function
  51  *  @param op Operation
  52  *  @param proc Owner of page
  53  *  @param page Page
  54  *  @return Success?
  55  */
  56 int swap_call(int op,proc_t *proc,void *page) {
  57   swap_call_t *new = malloc(sizeof(swap_call_t));
  58   if (new!=NULL) {
  59     new->op = op;
  60     new->pid = proc->pid;
  61     new->page = page;
  62     llist_push(swap_queue,new);
  63     return 0;
  64   }
  65   else return -1;
  66 }
  67
  68 /**
  69  * Swaps page in
  70  *  @param proc Onwer of page
  71  *  @param page Page to swap
  72  */
  73 int swap_in(proc_t *proc,void *page) {
  74   if (swap_proc!=NULL) {
  75     pte_t pte = paging_getpte_pd(page,proc->addrspace->pagedir);
  76     if (!pte.in_memory && pte.swapped) {
  77       memuser_load_addrspace(proc->addrspace);
  78       if (swap_call(SWAP_IN,proc,page)) {
  79         void *phys = memphys_alloc();
  80         pte.page = ADDR2PAGE(phys);
  81         pte.in_memory = 1;
  82         paging_physwrite(phys,swap_buf,PAGE_SIZE);
  83         return 0;
  84       }
  85     }
  86   }
  87   return -1;
  88 }
  89
  90 /**
  91  * Swaps page out
  92  *  @param proc Owner of page
  93  *  @param page Page to swap
  94  *  @return Success?
  95  */
  96 int swap_out(proc_t *proc,void *page) {
  97   if (swap_proc!=NULL) {
  98     pte_t pte = paging_getpte_pd(page,proc->addrspace->pagedir);
  99     if (pte.swappable) {
 100       memuser_load_addrspace(proc->addrspace);
 101       void *phys = PAGE2ADDR(pte.page);
 102       if (phys!=NULL && pte.in_memory) {
 103         paging_physread(swap_buf,phys,PAGE_SIZE);
 104         if (swap_call(SWAP_OUT,proc,page)!=-1) {
 105           pte.in_memory = 0;
 106           pte.swapped = 1;
 107           memphys_free(page);
 108           paging_setpte_pd(page,pte,proc->addrspace->pagedir);
 109           return 0;
 110         }
 111       }
 112     }
 113   }
 114   return -1;
 115 }
 116
 117 /**
 118  * Removes a page from swap
 119  *  @param proc Owner of page
 120  *  @param page Page
 121  *  @return Success?
 122  */
 123 int swap_remove(proc_t *proc,void *page) {
 124   if (swap_proc!=NULL) return swap_call(SWAP_REM,proc,page);
 125   else return -1;
 126 }