WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/mm/as.c

 /*
  * Copyright (C) 2001-2006 Jakub Jermar
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /*
  * This file contains address space manipulation functions.
  * Roughly speaking, this is a higher-level client of
  * Virtual Address Translation (VAT) subsystem.
  */
 #include <mm/as.h>
 #include <arch/mm/as.h>
 #include <mm/page.h>
 #include <mm/frame.h>
 #include <mm/slab.h>
 #include <mm/tlb.h>
 #include <arch/mm/page.h>
 #include <genarch/mm/page_pt.h>
 #include <mm/asid.h>
 #include <arch/mm/asid.h>
 #include <arch/types.h>
 #include <typedefs.h>
 #include <synch/spinlock.h>
 #include <config.h>
 #include <adt/list.h>
 #include <panic.h>
 #include <arch/asm.h>
 #include <debug.h>
 #include <memstr.h>
 #include <arch.h>
 #include <print.h>
 as_operations_t *as_operations = NULL;
 /** Address space lock. It protects inactive_as_with_asid_head. */
 SPINLOCK_INITIALIZE(as_lock);
 /**
  * This list contains address spaces that are not active on any
  * processor and that have valid ASID.
  */
 LIST_INITIALIZE(inactive_as_with_asid_head);
 /** Kernel address space. */
 as_t *AS_KERNEL = NULL;
 static int get_area_flags(as_area_t *a);
+static as_area_t *find_area_and_lock(as_t *as, __address va);
 /** Initialize address space subsystem. */
 void as_init(void)
+{
     as_arch_init();
     AS_KERNEL = as_create(FLAG_AS_KERNEL);
         if (!AS_KERNEL)
                 panic("can't create kernel address space\n");
+}
 /** Create address space.
+ *
  * @param flags Flags that influence way in wich the address space is created.
  */
 as_t *as_create(int flags)
+{
     as_t *as;
     as = (as_t *) malloc(sizeof(as_t), 0);
     link_initialize(&as->inactive_as_with_asid_link);
     spinlock_initialize(&as->lock, "as_lock");
     list_initialize(&as->as_area_head);
     if (flags & FLAG_AS_KERNEL)
         as->asid = ASID_KERNEL;
     else
         as->asid = ASID_INVALID;
     as->refcount = 0;
     as->page_table = page_table_create(flags);
     return as;
+}
 /** Free Adress space */
 void as_free(as_t *as)
+{
     ASSERT(as->refcount == 0);
     /* TODO: free as_areas and other resources held by as */
     /* TODO: free page table */
     free(as);
+}
 /** Create address space area of common attributes.
+ *
  * The created address space area is added to the target address space.
+ *
  * @param as Target address space.
  * @param type Type of area.
  * @param size Size of area in multiples of PAGE_SIZE.
  * @param base Base address of area.
+ *
  * @return Address space area on success or NULL on failure.
  */
 as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base)
+{
     ipl_t ipl;
     as_area_t *a;
     if (base % PAGE_SIZE)
         panic("addr not aligned to a page boundary");
     ipl = interrupts_disable();
     spinlock_lock(&as->lock);
     /*
      * TODO: test as_area which is to be created doesn't overlap with an existing one.
      */
     a = (as_area_t *) malloc(sizeof(as_area_t), 0);
     spinlock_initialize(&a->lock, "as_area_lock");
     link_initialize(&a->link);
     a->type = type;
     a->size = size;
     a->base = base;
     list_append(&a->link, &as->as_area_head);
     spinlock_unlock(&as->lock);
     interrupts_restore(ipl);
     return a;
+}
 /** Initialize mapping for one page of address space.
+ *
  * This functions maps 'page' to 'frame' according
  * to attributes of the address space area to
  * wich 'page' belongs.
+ *
  * @param as Target address space.
  * @param page Virtual page within the area.
  * @param frame Physical frame to which page will be mapped.
  */
 void as_set_mapping(as_t *as, __address page, __address frame)
+{
-    as_area_t *a, *area = NULL;
+    as_area_t *area;
-    link_t *cur;
     ipl_t ipl;
     ipl = interrupts_disable();
     spinlock_lock(&as->lock);
-    /*
-     * First, try locate an area.
-     */
-    for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
-        a = list_get_instance(cur, as_area_t, link);
+    area = find_area_and_lock(as, page);
-        spinlock_lock(&a->lock);
-        if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
-            area = a;
-            break;
-        }
-        spinlock_unlock(&a->lock);
-    }
     if (!area) {
         panic("page not part of any as_area\n");
+    }
-    /*
-     * Note: area->lock is held.
-     */
     page_mapping_insert(as, page, frame, get_area_flags(area));
     spinlock_unlock(&area->lock);
     spinlock_unlock(&as->lock);
     interrupts_restore(ipl);
+}
 /** Handle page fault within the current address space.
+ *
  * This is the high-level page fault handler.
  * Interrupts are assumed disabled.
+ *
  * @param page Faulting page.
+ *
  * @return 0 on page fault, 1 on success.
  */
 int as_page_fault(__address page)
+{
-    link_t *cur;
-    as_area_t *a, *area = NULL;
+    as_area_t *area;
     __address frame;
     ASSERT(AS);
     spinlock_lock(&AS->lock);
-    /*
-     * Search this areas of this address space for presence of 'page'.
-     */
-    for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {
-        a = list_get_instance(cur, as_area_t, link);
-        spinlock_lock(&a->lock);
-        if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {
-            /*
-             * We found the area containing 'page'.
+    area = find_area_and_lock(AS, page);
-             * TODO: access checking
-             */
-            area = a;
-            break;
-        }
-        spinlock_unlock(&a->lock);
-    }
     if (!area) {
         /*
          * No area contained mapping for 'page'.
          * Signal page fault to low-level handler.
          */
         spinlock_unlock(&AS->lock);
         return 0;
+    }
     /*
-     * Note: area->lock is held.
-     */
-    /*
      * In general, there can be several reasons that
      * can have caused this fault.
+     *
      * - non-existent mapping: the area is a scratch
      *   area (e.g. stack) and so far has not been
      *   allocated a frame for the faulting page
+     *
      * - non-present mapping: another possibility,
      *   currently not implemented, would be frame
      *   reuse; when this becomes a possibility,
      *   do not forget to distinguish between
      *   the different causes
      */
     frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
     memsetb(PA2KA(frame), FRAME_SIZE, 0);
     /*
      * Map 'page' to 'frame'.
      * Note that TLB shootdown is not attempted as only new information is being
      * inserted into page tables.
      */
     page_mapping_insert(AS, page, frame, get_area_flags(area));
     spinlock_unlock(&area->lock);
     spinlock_unlock(&AS->lock);
     return 1;
+}
 /** Switch address spaces.
+ *
  * @param old Old address space or NULL.
  * @param new New address space.
  */
 void as_switch(as_t *old, as_t *new)
+{
     ipl_t ipl;
     bool needs_asid = false;
     ipl = interrupts_disable();
     spinlock_lock(&as_lock);
     /*
      * First, take care of the old address space.
      */
     if (old) {
         spinlock_lock(&old->lock);
         ASSERT(old->refcount);
         if((--old->refcount == 0) && (old != AS_KERNEL)) {
             /*
              * The old address space is no longer active on
              * any processor. It can be appended to the
              * list of inactive address spaces with assigned
              * ASID.
              */
              ASSERT(old->asid != ASID_INVALID);
              list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
+        }
         spinlock_unlock(&old->lock);
+    }
     /*
      * Second, prepare the new address space.
      */
     spinlock_lock(&new->lock);
     if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
         if (new->asid != ASID_INVALID)
             list_remove(&new->inactive_as_with_asid_link);
         else
             needs_asid = true;  /* defer call to asid_get() until new->lock is released */
+    }
     SET_PTL0_ADDRESS(new->page_table);
     spinlock_unlock(&new->lock);
     if (needs_asid) {
         /*
          * Allocation of new ASID was deferred
          * until now in order to avoid deadlock.
          */
         asid_t asid;
         asid = asid_get();
         spinlock_lock(&new->lock);
         new->asid = asid;
         spinlock_unlock(&new->lock);
+    }
     spinlock_unlock(&as_lock);
     interrupts_restore(ipl);
     /*
      * Perform architecture-specific steps.
      * (e.g. write ASID to hardware register etc.)
      */
     as_install_arch(new);
     AS = new;
+}
 /** Compute flags for virtual address translation subsytem.
+ *
  * The address space area must be locked.
  * Interrupts must be disabled.
+ *
  * @param a Address space area.
+ *
  * @return Flags to be used in page_mapping_insert().
  */
 int get_area_flags(as_area_t *a)
+{
     int flags;
     switch (a->type) {
         case AS_AREA_TEXT:
             flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
             break;
         case AS_AREA_DATA:
         case AS_AREA_STACK:
             flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;
             break;
         default:
             panic("unexpected as_area_type_t %d", a->type);
+    }
     return flags;
+}
 /** Create page table.
+ *
  * Depending on architecture, create either address space
  * private or global page table.
+ *
  * @param flags Flags saying whether the page table is for kernel address space.
+ *
  * @return First entry of the page table.
  */
 pte_t *page_table_create(int flags)
+{
         ASSERT(as_operations);
         ASSERT(as_operations->page_table_create);
         return as_operations->page_table_create(flags);
+}
+/** Find address space area and change it.
+ *
+ * @param as Address space.
+ * @param address Virtual address belonging to the area to be changed. Must be page-aligned.
+ * @param size New size of the virtual memory block starting at address.
+ * @param flags Flags influencing the remap operation. Currently unused.
+ *
+ * @return address on success, (__address) -1 otherwise.
+ */
+__address as_remap(as_t *as, __address address, size_t size, int flags)
+{
+    as_area_t *area = NULL;
+    ipl_t ipl;
+    size_t pages;
+    ipl = interrupts_disable();
+    spinlock_lock(&as->lock);
+    /*
+     * Locate the area.
+     */
+    area = find_area_and_lock(as, address);
+    if (!area) {
+        spinlock_unlock(&as->lock);
+        return (__address) -1;
+    }
+    pages = SIZE2FRAMES((address - area->base) + size);
+    if (pages < area->size) {
+        int i;
+        /*
+         * Shrinking the area.
+         */
+        for (i = pages; i < area->size; i++) {
+            pte_t *pte;
+            /*
+             * Releasing physical memory.
+             * This depends on the fact that the memory was allocated using frame_alloc().
+             */
+            pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
+            if (pte) {
+                ASSERT(PTE_PRESENT(pte));
+                frame_free(ADDR2PFN(PTE_GET_FRAME(pte)));
+            }
+            page_mapping_remove(as, area->base + i*PAGE_SIZE);
+        }
+        /*
+         * Invalidate TLB's.
+         */
+        tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
+        tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->size - pages);
+        tlb_shootdown_finalize();
+    } else {
+        /*
+         * Growing the area.
+         */
+        area->size = size;
+    }
+    spinlock_unlock(&area->lock);
+    spinlock_unlock(&as->lock);
+    interrupts_restore(ipl);
+    return address;
+}
+/** Find address space area and lock it.
+ *
+ * The address space must be locked and interrupts must be disabled.
+ *
+ * @param as Address space.
+ * @param va Virtual address.
+ *
+ * @return Locked address space area containing va on success or NULL on failure.
+ */
+as_area_t *find_area_and_lock(as_t *as, __address va)
+{
+    link_t *cur;
+    as_area_t *a;
+    for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) {
+        a = list_get_instance(cur, as_area_t, link);
+        spinlock_lock(&a->lock);
+        if ((va >= a->base) && (va < a->base + a->size * PAGE_SIZE))
+             return a;
+        spinlock_unlock(&a->lock);
+    }
+    return NULL;
+}

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/as.c – Rev 973 → 977