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 <genarch/mm/page_ht.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 <adt/btree.h>
-#include <panic.h>
+#include <proc/task.h>
 #include <arch/asm.h>
+#include <panic.h>
 #include <debug.h>
+#include <print.h>
 #include <memstr.h>
 #include <macros.h>
 #include <arch.h>
-#include <print.h>
+#include <errno.h>
+#include <config.h>
+#include <arch/types.h>
+#include <typedefs.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 area_flags_to_page_flags(int aflags);
 static int get_area_flags(as_area_t *a);
 static as_area_t *find_area_and_lock(as_t *as, __address va);
 static bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area);
 /** 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");
     btree_create(&as->as_area_btree);
     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 flags Flags of the area.
  * @param size Size of area.
  * @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, int flags, size_t size, __address base)
+{
     ipl_t ipl;
     as_area_t *a;
     if (base % PAGE_SIZE)
         return NULL;
     if (!size)
         return NULL;
     /* Writeable executable areas are not supported. */
     if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
         return NULL;
     ipl = interrupts_disable();
     spinlock_lock(&as->lock);
     if (!check_area_conflicts(as, base, size, NULL)) {
         spinlock_unlock(&as->lock);
         interrupts_restore(ipl);
         return NULL;
+    }
     a = (as_area_t *) malloc(sizeof(as_area_t), 0);
     spinlock_initialize(&a->lock, "as_area_lock");
     a->flags = flags;
     a->pages = SIZE2FRAMES(size);
     a->base = base;
     btree_insert(&as->as_area_btree, base, (void *) a, NULL);
     spinlock_unlock(&as->lock);
     interrupts_restore(ipl);
     return a;
+}
+/** 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_area_resize(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);
+        interrupts_restore(ipl);
+        return (__address) -1;
+    }
+    if (area->flags & AS_AREA_DEVICE) {
+        /*
+         * Remapping of address space areas associated
+         * with memory mapped devices is not supported.
+         */
+        spinlock_unlock(&area->lock);
+        spinlock_unlock(&as->lock);
+        interrupts_restore(ipl);
+        return (__address) -1;
+    }
+    pages = SIZE2FRAMES((address - area->base) + size);
+    if (!pages) {
+        /*
+         * Zero size address space areas are not allowed.
+         */
+        spinlock_unlock(&area->lock);
+        spinlock_unlock(&as->lock);
+        interrupts_restore(ipl);
+        return (__address) -1;
+    }
+    if (pages < area->pages) {
+        int i;
+        /*
+         * Shrinking the area.
+         * No need to check for overlaps.
+         */
+        for (i = pages; i < area->pages; i++) {
+            pte_t *pte;
+            /*
+             * Releasing physical memory.
+             * This depends on the fact that the memory was allocated using frame_alloc().
+             */
+            page_table_lock(as, false);
+            pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
+            if (pte && PTE_VALID(pte)) {
+                __address frame;
+                ASSERT(PTE_PRESENT(pte));
+                frame = PTE_GET_FRAME(pte);
+                page_mapping_remove(as, area->base + i*PAGE_SIZE);
+                page_table_unlock(as, false);
+                frame_free(ADDR2PFN(frame));
+            } else {
+                page_table_unlock(as, false);
+            }
+        }
+        /*
+         * Invalidate TLB's.
+         */
+        tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
+        tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
+        tlb_shootdown_finalize();
+    } else {
+        /*
+         * Growing the area.
+         * Check for overlaps with other address space areas.
+         */
+        if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
+            spinlock_unlock(&area->lock);
+            spinlock_unlock(&as->lock);
+            interrupts_restore(ipl);
+            return (__address) -1;
+        }
+    }
+    area->pages = pages;
+    spinlock_unlock(&area->lock);
+    spinlock_unlock(&as->lock);
+    interrupts_restore(ipl);
+    return address;
+}
+/** Send address space area to another task.
+ *
+ * Address space area is sent to the specified task.
+ * If the destination task is willing to accept the
+ * area, a new area is created according to the
+ * source area. Moreover, any existing mapping
+ * is copied as well, providing thus a mechanism
+ * for sharing group of pages. The source address
+ * space area and any associated mapping is preserved.
+ *
+ * @param id Task ID of the accepting task.
+ * @param base Base address of the source address space area.
+ * @param size Size of the source address space area.
+ * @param flags Flags of the source address space area.
+ *
+ * @return 0 on success or ENOENT if there is no such task or
+ *     if there is no such address space area,
+ *     EPERM if there was a problem in accepting the area or
+ *     ENOMEM if there was a problem in allocating destination
+ *     address space area.
+ */
+int as_area_send(task_id_t id, __address base, size_t size, int flags)
+{
+    ipl_t ipl;
+    task_t *t;
+    count_t i;
+    as_t *as;
+    __address dst_base;
+    ipl = interrupts_disable();
+    spinlock_lock(&tasks_lock);
+    t = task_find_by_id(id);
+    if (!NULL) {
+        spinlock_unlock(&tasks_lock);
+        interrupts_restore(ipl);
+        return ENOENT;
+    }
+    spinlock_lock(&t->lock);
+    spinlock_unlock(&tasks_lock);
+    as = t->as;
+    dst_base = (__address) t->accept_arg.base;
+    if (as == AS) {
+        /*
+         * The two tasks share the entire address space.
+         * Return error since there is no point in continuing.
+         */
+        spinlock_unlock(&t->lock);
+        interrupts_restore(ipl);
+        return EPERM;
+    }
+    if ((t->accept_arg.task_id != TASK->taskid) || (t->accept_arg.size != size) ||
+        (t->accept_arg.flags != flags)) {
+        /*
+         * Discrepancy in either task ID, size or flags.
+         */
+        spinlock_unlock(&t->lock);
+        interrupts_restore(ipl);
+        return EPERM;
+    }
+    /*
+     * Create copy of the address space area.
+     */
+    if (!as_area_create(as, flags, size, dst_base)) {
+        /*
+         * Destination address space area could not be created.
+         */
+        spinlock_unlock(&t->lock);
+        interrupts_restore(ipl);
+        return ENOMEM;
+    }
+    /*
+     * NOTE: we have just introduced a race condition.
+     * The destination task can try to attempt the newly
+     * created area before its mapping is copied from
+     * the source address space area. In result, frames
+     * can get lost.
+     *
+     * Currently, this race is not solved, but one of the
+     * possible solutions would be to sleep in as_page_fault()
+     * when this situation is detected.
+     */
+    memsetb((__address) &t->accept_arg, sizeof(as_area_acptsnd_arg_t), 0);
+    spinlock_unlock(&t->lock);
+    /*
+     * Avoid deadlock by first locking the address space with lower address.
+     */
+    if (as < AS) {
+        spinlock_lock(&as->lock);
+        spinlock_lock(&AS->lock);
+    } else {
+        spinlock_lock(&AS->lock);
+        spinlock_lock(&as->lock);
+    }
+    for (i = 0; i < SIZE2FRAMES(size); i++) {
+        pte_t *pte;
+        __address frame;
+        page_table_lock(AS, false);
+        pte = page_mapping_find(AS, base + i*PAGE_SIZE);
+        if (pte && PTE_VALID(pte)) {
+            ASSERT(PTE_PRESENT(pte));
+            frame = PTE_GET_FRAME(pte);
+            if (!(flags & AS_AREA_DEVICE)) {
+                /* TODO: increment frame reference count */
+            }
+            page_table_unlock(AS, false);
+        } else {
+            page_table_unlock(AS, false);
+            continue;
+        }
+        page_table_lock(as, false);
+        page_mapping_insert(as, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(flags));
+        page_table_unlock(as, false);
+    }
+    spinlock_unlock(&AS->lock);
+    spinlock_unlock(&as->lock);
+    interrupts_restore(ipl);
+    return 0;
+}
 /** 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 *area;
     ipl_t ipl;
     ipl = interrupts_disable();
     page_table_lock(as, true);
     area = find_area_and_lock(as, page);
     if (!area) {
         panic("page not part of any as_area\n");
+    }
     page_mapping_insert(as, page, frame, get_area_flags(area));
     spinlock_unlock(&area->lock);
     page_table_unlock(as, true);
     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)
+{
     pte_t *pte;
     as_area_t *area;
     __address frame;
     ASSERT(AS);
     spinlock_lock(&AS->lock);
     area = find_area_and_lock(AS, page);
     if (!area) {
         /*
          * No area contained mapping for 'page'.
          * Signal page fault to low-level handler.
          */
         spinlock_unlock(&AS->lock);
         return 0;
+    }
     ASSERT(!(area->flags & AS_AREA_DEVICE));
     page_table_lock(AS, false);
     /*
      * To avoid race condition between two page faults
      * on the same address, we need to make sure
      * the mapping has not been already inserted.
      */
     if ((pte = page_mapping_find(AS, page))) {
         if (PTE_PRESENT(pte)) {
             page_table_unlock(AS, false);
             spinlock_unlock(&area->lock);
             spinlock_unlock(&AS->lock);
             return 1;
+        }
+    }
     /*
      * 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));
     page_table_unlock(AS, false);
     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.
+/** Convert address space area flags to page flags.
+ *
- * The address space area must be locked.
- * Interrupts must be disabled.
- *
- * @param a Address space area.
+ * @param aflags Flags of some address space area.
+ *
- * @return Flags to be used in page_mapping_insert().
+ * @return Flags to be passed to page_mapping_insert().
  */
-int get_area_flags(as_area_t *a)
+int area_flags_to_page_flags(int aflags)
+{
     int flags;
     flags = PAGE_USER | PAGE_PRESENT;
-    if (a->flags & AS_AREA_READ)
+    if (aflags & AS_AREA_READ)
         flags |= PAGE_READ;
-    if (a->flags & AS_AREA_WRITE)
+    if (aflags & AS_AREA_WRITE)
         flags |= PAGE_WRITE;
-    if (a->flags & AS_AREA_EXEC)
+    if (aflags & AS_AREA_EXEC)
         flags |= PAGE_EXEC;
-    if (!(a->flags & AS_AREA_DEVICE))
+    if (!(aflags & AS_AREA_DEVICE))
         flags |= PAGE_CACHEABLE;
     return flags;
+}
+/** 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)
+{
+    return area_flags_to_page_flags(a->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);
+}
 /** Lock page table.
+ *
  * This function should be called before any page_mapping_insert(),
  * page_mapping_remove() and page_mapping_find().
+ *
  * Locking order is such that address space areas must be locked
  * prior to this call. Address space can be locked prior to this
  * call in which case the lock argument is false.
+ *
  * @param as Address space.
  * @param as_locked If false, do not attempt to lock as->lock.
  */
 void page_table_lock(as_t *as, bool lock)
+{
     ASSERT(as_operations);
     ASSERT(as_operations->page_table_lock);
     as_operations->page_table_lock(as, lock);
+}
 /** Unlock page table.
+ *
  * @param as Address space.
  * @param as_locked If false, do not attempt to unlock as->lock.
  */
 void page_table_unlock(as_t *as, bool unlock)
+{
     ASSERT(as_operations);
     ASSERT(as_operations->page_table_unlock);
     as_operations->page_table_unlock(as, unlock);
+}
-/** 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_area_resize(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);
-        interrupts_restore(ipl);
-        return (__address) -1;
-    }
-    if (area->flags & AS_AREA_DEVICE) {
-        /*
-         * Remapping of address space areas associated
-         * with memory mapped devices is not supported.
-         */
-        spinlock_unlock(&area->lock);
-        spinlock_unlock(&as->lock);
-        interrupts_restore(ipl);
-        return (__address) -1;
-    }
-    pages = SIZE2FRAMES((address - area->base) + size);
-    if (!pages) {
-        /*
-         * Zero size address space areas are not allowed.
-         */
-        spinlock_unlock(&area->lock);
-        spinlock_unlock(&as->lock);
-        interrupts_restore(ipl);
-        return (__address) -1;
-    }
-    if (pages < area->pages) {
-        int i;
-        /*
-         * Shrinking the area.
-         * No need to check for overlaps.
-         */
-        for (i = pages; i < area->pages; i++) {
-            pte_t *pte;
-            /*
-             * Releasing physical memory.
-             * This depends on the fact that the memory was allocated using frame_alloc().
-             */
-            page_table_lock(as, false);
-            pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
-            if (pte && PTE_VALID(pte)) {
-                __address frame;
-                ASSERT(PTE_PRESENT(pte));
-                frame = PTE_GET_FRAME(pte);
-                page_mapping_remove(as, area->base + i*PAGE_SIZE);
-                page_table_unlock(as, false);
-                frame_free(ADDR2PFN(frame));
-            } else {
-                page_table_unlock(as, false);
-            }
-        }
-        /*
-         * Invalidate TLB's.
-         */
-        tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
-        tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
-        tlb_shootdown_finalize();
-    } else {
-        /*
-         * Growing the area.
-         * Check for overlaps with other address space areas.
-         */
-        if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
-            spinlock_unlock(&area->lock);
-            spinlock_unlock(&as->lock);
-            interrupts_restore(ipl);
-            return (__address) -1;
-        }
-    }
-    area->pages = pages;
-    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)
+{
     as_area_t *a;
     btree_node_t *leaf, *lnode;
     int i;
     a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf);
     if (a) {
         /* va is the base address of an address space area */
         spinlock_lock(&a->lock);
         return a;
+    }
     /*
      * Search the leaf node and the righmost record of its left neighbour
      * to find out whether this is a miss or va belongs to an address
      * space area found there.
      */
     /* First, search the leaf node itself. */
     for (i = 0; i < leaf->keys; i++) {
         a = (as_area_t *) leaf->value[i];
         spinlock_lock(&a->lock);
         if ((a->base <= va) && (va < a->base + a->pages * PAGE_SIZE)) {
             return a;
+        }
         spinlock_unlock(&a->lock);
+    }
     /*
      * Second, locate the left neighbour and test its last record.
      * Because of its position in the B+tree, it must have base < va.
      */
     if ((lnode = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) {
         a = (as_area_t *) lnode->value[lnode->keys - 1];
         spinlock_lock(&a->lock);
         if (va < a->base + a->pages * PAGE_SIZE) {
             return a;
+        }
         spinlock_unlock(&a->lock);
+    }
     return NULL;
+}
 /** Check area conflicts with other areas.
+ *
  * The address space must be locked and interrupts must be disabled.
+ *
  * @param as Address space.
  * @param va Starting virtual address of the area being tested.
  * @param size Size of the area being tested.
  * @param avoid_area Do not touch this area.
+ *
  * @return True if there is no conflict, false otherwise.
  */
 bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area)
+{
     as_area_t *a;
     btree_node_t *leaf, *node;
     int i;
     /*
      * We don't want any area to have conflicts with NULL page.
      */
     if (overlaps(va, size, NULL, PAGE_SIZE))
         return false;
     /*
      * The leaf node is found in O(log n), where n is proportional to
      * the number of address space areas belonging to as.
      * The check for conflicts is then attempted on the rightmost
      * record in the left neighbour, the leftmost record in the right
      * neighbour and all records in the leaf node itself.
      */
     if ((a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf))) {
         if (a != avoid_area)
             return false;
+    }
     /* First, check the two border cases. */
     if ((node = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) {
         a = (as_area_t *) node->value[node->keys - 1];
         spinlock_lock(&a->lock);
         if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
             spinlock_unlock(&a->lock);
             return false;
+        }
         spinlock_unlock(&a->lock);
+    }
     if ((node = btree_leaf_node_right_neighbour(&as->as_area_btree, leaf))) {
         a = (as_area_t *) node->value[0];
         spinlock_lock(&a->lock);
         if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
             spinlock_unlock(&a->lock);
             return false;
+        }
         spinlock_unlock(&a->lock);
+    }
     /* Second, check the leaf node. */
     for (i = 0; i < leaf->keys; i++) {
         a = (as_area_t *) leaf->value[i];
         if (a == avoid_area)
             continue;
         spinlock_lock(&a->lock);
         if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
             spinlock_unlock(&a->lock);
             return false;
+        }
         spinlock_unlock(&a->lock);
+    }
     /*
      * So far, the area does not conflict with other areas.
      * Check if it doesn't conflict with kernel address space.
      */
     if (!KERNEL_ADDRESS_SPACE_SHADOWED) {
         return !overlaps(va, size,
             KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START);
+    }
     return true;
+}
+/*
+ * Address space related syscalls.
+ */
+/** Wrapper for as_area_create(). */
+__native sys_as_area_create(__address address, size_t size, int flags)
+{
+    if (as_area_create(AS, flags, size, address))
+        return (__native) address;
+    else
+        return (__native) -1;
+}
+/** Wrapper for as_area_resize. */
+__native sys_as_area_resize(__address address, size_t size, int flags)
+{
+    return as_area_resize(AS, address, size, 0);
+}
+/** Prepare task for accepting address space area from another task.
+ *
+ * @param uspace_accept_arg Accept structure passed from userspace.
+ *
+ * @return EPERM if the task ID encapsulated in @uspace_accept_arg references
+ *     TASK. Otherwise zero is returned.
+ */
+__native sys_as_area_accept(as_area_acptsnd_arg_t *uspace_accept_arg)
+{
+    as_area_acptsnd_arg_t arg;
+    copy_from_uspace(&arg, uspace_accept_arg, sizeof(as_area_acptsnd_arg_t));
+    if (!arg.size)
+        return (__native) EPERM;
+    if (arg.task_id == TASK->taskid) {
+        /*
+         * Accepting from itself is not allowed.
+         */
+        return (__native) EPERM;
+    }
+    memcpy(&TASK->accept_arg, &arg, sizeof(as_area_acptsnd_arg_t));
+        return 0;
+}
+/** Wrapper for as_area_send. */
+__native sys_as_area_send(as_area_acptsnd_arg_t *uspace_send_arg)
+{
+    as_area_acptsnd_arg_t arg;
+    copy_from_uspace(&arg, uspace_send_arg, sizeof(as_area_acptsnd_arg_t));
+    if (!arg.size)
+        return (__native) EPERM;
+    if (arg.task_id == TASK->taskid) {
+        /*
+         * Sending to itself is not allowed.
+         */
+        return (__native) EPERM;
+    }
+    return (__native) as_area_send(arg.task_id, (__address) arg.base, arg.size, arg.flags);
+}

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(root)/kernel/trunk/generic/src/mm/as.c – Rev 1233 → 1235