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 <arch/asm.h>
#include <debug.h>
#include <memstr.h>
#include <macros.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);
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;
}
 
/** 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.
 *
 * 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;
 
    flags = PAGE_USER | PAGE_PRESENT;
   
    if (a->flags & AS_AREA_READ)
        flags |= PAGE_READ;
       
    if (a->flags & AS_AREA_WRITE)
        flags |= PAGE_WRITE;
   
    if (a->flags & AS_AREA_EXEC)
        flags |= PAGE_EXEC;
   
    if (!(a->flags & AS_AREA_DEVICE))
        flags |= PAGE_CACHEABLE;
       
    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);
}
 
/** 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;
}
 

Rev 1227	Rev 1233
1	/*	1	/*
2	* Copyright (C) 2001-2006 Jakub Jermar	2	* Copyright (C) 2001-2006 Jakub Jermar
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	13	* documentation and/or other materials provided with the distribution.
14	* - The name of the author may not be used to endorse or promote products	14	* - The name of the author may not be used to endorse or promote products
15	* derived from this software without specific prior written permission.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF	25	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	/*	29	/*
30	* This file contains address space manipulation functions.	30	* This file contains address space manipulation functions.
31	* Roughly speaking, this is a higher-level client of	31	* Roughly speaking, this is a higher-level client of
32	* Virtual Address Translation (VAT) subsystem.	32	* Virtual Address Translation (VAT) subsystem.
33	*/	33	*/
34		34
35	#include <mm/as.h>	35	#include <mm/as.h>
36	#include <arch/mm/as.h>	36	#include <arch/mm/as.h>
37	#include <mm/page.h>	37	#include <mm/page.h>
38	#include <mm/frame.h>	38	#include <mm/frame.h>
39	#include <mm/slab.h>	39	#include <mm/slab.h>
40	#include <mm/tlb.h>	40	#include <mm/tlb.h>
41	#include <arch/mm/page.h>	41	#include <arch/mm/page.h>
42	#include <genarch/mm/page_pt.h>	42	#include <genarch/mm/page_pt.h>
43	#include <genarch/mm/page_ht.h>	43	#include <genarch/mm/page_ht.h>
44	#include <mm/asid.h>	44	#include <mm/asid.h>
45	#include <arch/mm/asid.h>	45	#include <arch/mm/asid.h>
46	#include <arch/types.h>	46	#include <arch/types.h>
47	#include <typedefs.h>	47	#include <typedefs.h>
48	#include <synch/spinlock.h>	48	#include <synch/spinlock.h>
49	#include <config.h>	49	#include <config.h>
50	#include <adt/list.h>	50	#include <adt/list.h>
51	#include <adt/btree.h>	51	#include <adt/btree.h>
52	#include <panic.h>	52	#include <panic.h>
53	#include <arch/asm.h>	53	#include <arch/asm.h>
54	#include <debug.h>	54	#include <debug.h>
55	#include <memstr.h>	55	#include <memstr.h>
56	#include <macros.h>	56	#include <macros.h>
57	#include <arch.h>	57	#include <arch.h>
58	#include <print.h>	58	#include <print.h>
59		59
60	as_operations_t *as_operations = NULL;	60	as_operations_t *as_operations = NULL;
61		61
62	/** Address space lock. It protects inactive_as_with_asid_head. */	62	/** Address space lock. It protects inactive_as_with_asid_head. */
63	SPINLOCK_INITIALIZE(as_lock);	63	SPINLOCK_INITIALIZE(as_lock);
64		64
65	/**	65	/**
66	* This list contains address spaces that are not active on any	66	* This list contains address spaces that are not active on any
67	* processor and that have valid ASID.	67	* processor and that have valid ASID.
68	*/	68	*/
69	LIST_INITIALIZE(inactive_as_with_asid_head);	69	LIST_INITIALIZE(inactive_as_with_asid_head);
70		70
71	/** Kernel address space. */	71	/** Kernel address space. */
72	as_t *AS_KERNEL = NULL;	72	as_t *AS_KERNEL = NULL;
73		73
74	static int get_area_flags(as_area_t *a);	74	static int get_area_flags(as_area_t *a);
75	static as_area_t find_area_and_lock(as_t as, __address va);	75	static as_area_t find_area_and_lock(as_t as, __address va);
76	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);	76	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);
77		77
78	/** Initialize address space subsystem. */	78	/** Initialize address space subsystem. */
79	void as_init(void)	79	void as_init(void)
80	{	80	{
81	as_arch_init();	81	as_arch_init();
82	AS_KERNEL = as_create(FLAG_AS_KERNEL);	82	AS_KERNEL = as_create(FLAG_AS_KERNEL);
83	if (!AS_KERNEL)	83	if (!AS_KERNEL)
84	panic("can't create kernel address space\n");	84	panic("can't create kernel address space\n");
85	}	85	}
86		86
87	/** Create address space.	87	/** Create address space.
88	*	88	*
89	* @param flags Flags that influence way in wich the address space is created.	89	* @param flags Flags that influence way in wich the address space is created.
90	*/	90	*/
91	as_t *as_create(int flags)	91	as_t *as_create(int flags)
92	{	92	{
93	as_t *as;	93	as_t *as;
94		94
95	as = (as_t *) malloc(sizeof(as_t), 0);	95	as = (as_t *) malloc(sizeof(as_t), 0);
96	link_initialize(&as->inactive_as_with_asid_link);	96	link_initialize(&as->inactive_as_with_asid_link);
97	spinlock_initialize(&as->lock, "as_lock");	97	spinlock_initialize(&as->lock, "as_lock");
98	btree_create(&as->as_area_btree);	98	btree_create(&as->as_area_btree);
99		99
100	if (flags & FLAG_AS_KERNEL)	100	if (flags & FLAG_AS_KERNEL)
101	as->asid = ASID_KERNEL;	101	as->asid = ASID_KERNEL;
102	else	102	else
103	as->asid = ASID_INVALID;	103	as->asid = ASID_INVALID;
104		104
105	as->refcount = 0;	105	as->refcount = 0;
106	as->page_table = page_table_create(flags);	106	as->page_table = page_table_create(flags);
107		107
108	return as;	108	return as;
109	}	109	}
110		110
111	/** Free Adress space */	111	/** Free Adress space */
112	void as_free(as_t *as)	112	void as_free(as_t *as)
113	{	113	{
114	ASSERT(as->refcount == 0);	114	ASSERT(as->refcount == 0);
115		115
116	/* TODO: free as_areas and other resources held by as */	116	/* TODO: free as_areas and other resources held by as */
117	/* TODO: free page table */	117	/* TODO: free page table */
118	free(as);	118	free(as);
119	}	119	}
120		120
121	/** Create address space area of common attributes.	121	/** Create address space area of common attributes.
122	*	122	*
123	* The created address space area is added to the target address space.	123	* The created address space area is added to the target address space.
124	*	124	*
125	* @param as Target address space.	125	* @param as Target address space.
126	* @param flags Flags of the area.	126	* @param flags Flags of the area.
127	* @param size Size of area.	127	* @param size Size of area.
128	* @param base Base address of area.	128	* @param base Base address of area.
129	*	129	*
130	* @return Address space area on success or NULL on failure.	130	* @return Address space area on success or NULL on failure.
131	*/	131	*/
132	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)	132	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)
133	{	133	{
134	ipl_t ipl;	134	ipl_t ipl;
135	as_area_t *a;	135	as_area_t *a;
136		136
137	if (base % PAGE_SIZE)	137	if (base % PAGE_SIZE)
138	return NULL;	138	return NULL;
139		139
-		140	if (!size)
-		141	return NULL;
-		142
140	/* Writeable executable areas are not supported. */	143	/* Writeable executable areas are not supported. */
141	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))	144	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
142	return NULL;	145	return NULL;
143		146
144	ipl = interrupts_disable();	147	ipl = interrupts_disable();
145	spinlock_lock(&as->lock);	148	spinlock_lock(&as->lock);
146		149
147	if (!check_area_conflicts(as, base, size, NULL)) {	150	if (!check_area_conflicts(as, base, size, NULL)) {
148	spinlock_unlock(&as->lock);	151	spinlock_unlock(&as->lock);
149	interrupts_restore(ipl);	152	interrupts_restore(ipl);
150	return NULL;	153	return NULL;
151	}	154	}
152		155
153	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	156	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
154		157
155	spinlock_initialize(&a->lock, "as_area_lock");	158	spinlock_initialize(&a->lock, "as_area_lock");
156		159
157	a->flags = flags;	160	a->flags = flags;
158	a->pages = SIZE2FRAMES(size);	161	a->pages = SIZE2FRAMES(size);
159	a->base = base;	162	a->base = base;
160		163
161	btree_insert(&as->as_area_btree, base, (void *) a, NULL);	164	btree_insert(&as->as_area_btree, base, (void *) a, NULL);
162		165
163	spinlock_unlock(&as->lock);	166	spinlock_unlock(&as->lock);
164	interrupts_restore(ipl);	167	interrupts_restore(ipl);
165		168
166	return a;	169	return a;
167	}	170	}
168		171
169	/** Initialize mapping for one page of address space.	172	/** Initialize mapping for one page of address space.
170	*	173	*
171	* This functions maps 'page' to 'frame' according	174	* This functions maps 'page' to 'frame' according
172	* to attributes of the address space area to	175	* to attributes of the address space area to
173	* wich 'page' belongs.	176	* wich 'page' belongs.
174	*	177	*
175	* @param as Target address space.	178	* @param as Target address space.
176	* @param page Virtual page within the area.	179	* @param page Virtual page within the area.
177	* @param frame Physical frame to which page will be mapped.	180	* @param frame Physical frame to which page will be mapped.
178	*/	181	*/
179	void as_set_mapping(as_t *as, __address page, __address frame)	182	void as_set_mapping(as_t *as, __address page, __address frame)
180	{	183	{
181	as_area_t *area;	184	as_area_t *area;
182	ipl_t ipl;	185	ipl_t ipl;
183		186
184	ipl = interrupts_disable();	187	ipl = interrupts_disable();
185	page_table_lock(as, true);	188	page_table_lock(as, true);
186		189
187	area = find_area_and_lock(as, page);	190	area = find_area_and_lock(as, page);
188	if (!area) {	191	if (!area) {
189	panic("page not part of any as_area\n");	192	panic("page not part of any as_area\n");
190	}	193	}
191		194
192	page_mapping_insert(as, page, frame, get_area_flags(area));	195	page_mapping_insert(as, page, frame, get_area_flags(area));
193		196
194	spinlock_unlock(&area->lock);	197	spinlock_unlock(&area->lock);
195	page_table_unlock(as, true);	198	page_table_unlock(as, true);
196	interrupts_restore(ipl);	199	interrupts_restore(ipl);
197	}	200	}
198		201
199	/** Handle page fault within the current address space.	202	/** Handle page fault within the current address space.
200	*	203	*
201	* This is the high-level page fault handler.	204	* This is the high-level page fault handler.
202	* Interrupts are assumed disabled.	205	* Interrupts are assumed disabled.
203	*	206	*
204	* @param page Faulting page.	207	* @param page Faulting page.
205	*	208	*
206	* @return 0 on page fault, 1 on success.	209	* @return 0 on page fault, 1 on success.
207	*/	210	*/
208	int as_page_fault(__address page)	211	int as_page_fault(__address page)
209	{	212	{
210	pte_t *pte;	213	pte_t *pte;
211	as_area_t *area;	214	as_area_t *area;
212	__address frame;	215	__address frame;
213		216
214	ASSERT(AS);	217	ASSERT(AS);
215		218
216	spinlock_lock(&AS->lock);	219	spinlock_lock(&AS->lock);
217	area = find_area_and_lock(AS, page);	220	area = find_area_and_lock(AS, page);
218	if (!area) {	221	if (!area) {
219	/*	222	/*
220	* No area contained mapping for 'page'.	223	* No area contained mapping for 'page'.
221	* Signal page fault to low-level handler.	224	* Signal page fault to low-level handler.
222	*/	225	*/
223	spinlock_unlock(&AS->lock);	226	spinlock_unlock(&AS->lock);
224	return 0;	227	return 0;
225	}	228	}
226		229
227	ASSERT(!(area->flags & AS_AREA_DEVICE));	230	ASSERT(!(area->flags & AS_AREA_DEVICE));
228		231
229	page_table_lock(AS, false);	232	page_table_lock(AS, false);
230		233
231	/*	234	/*
232	* To avoid race condition between two page faults	235	* To avoid race condition between two page faults
233	* on the same address, we need to make sure	236	* on the same address, we need to make sure
234	* the mapping has not been already inserted.	237	* the mapping has not been already inserted.
235	*/	238	*/
236	if ((pte = page_mapping_find(AS, page))) {	239	if ((pte = page_mapping_find(AS, page))) {
237	if (PTE_PRESENT(pte)) {	240	if (PTE_PRESENT(pte)) {
238	page_table_unlock(AS, false);	241	page_table_unlock(AS, false);
239	spinlock_unlock(&area->lock);	242	spinlock_unlock(&area->lock);
240	spinlock_unlock(&AS->lock);	243	spinlock_unlock(&AS->lock);
241	return 1;	244	return 1;
242	}	245	}
243	}	246	}
244		247
245	/*	248	/*
246	* In general, there can be several reasons that	249	* In general, there can be several reasons that
247	* can have caused this fault.	250	* can have caused this fault.
248	*	251	*
249	* - non-existent mapping: the area is a scratch	252	* - non-existent mapping: the area is a scratch
250	* area (e.g. stack) and so far has not been	253	* area (e.g. stack) and so far has not been
251	* allocated a frame for the faulting page	254	* allocated a frame for the faulting page
252	*	255	*
253	* - non-present mapping: another possibility,	256	* - non-present mapping: another possibility,
254	* currently not implemented, would be frame	257	* currently not implemented, would be frame
255	* reuse; when this becomes a possibility,	258	* reuse; when this becomes a possibility,
256	* do not forget to distinguish between	259	* do not forget to distinguish between
257	* the different causes	260	* the different causes
258	*/	261	*/
259	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));	262	frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
260	memsetb(PA2KA(frame), FRAME_SIZE, 0);	263	memsetb(PA2KA(frame), FRAME_SIZE, 0);
261		264
262	/*	265	/*
263	* Map 'page' to 'frame'.	266	* Map 'page' to 'frame'.
264	* Note that TLB shootdown is not attempted as only new information is being	267	* Note that TLB shootdown is not attempted as only new information is being
265	* inserted into page tables.	268	* inserted into page tables.
266	*/	269	*/
267	page_mapping_insert(AS, page, frame, get_area_flags(area));	270	page_mapping_insert(AS, page, frame, get_area_flags(area));
268	page_table_unlock(AS, false);	271	page_table_unlock(AS, false);
269		272
270	spinlock_unlock(&area->lock);	273	spinlock_unlock(&area->lock);
271	spinlock_unlock(&AS->lock);	274	spinlock_unlock(&AS->lock);
272	return 1;	275	return 1;
273	}	276	}
274		277
275	/** Switch address spaces.	278	/** Switch address spaces.
276	*	279	*
277	* @param old Old address space or NULL.	280	* @param old Old address space or NULL.
278	* @param new New address space.	281	* @param new New address space.
279	*/	282	*/
280	void as_switch(as_t old, as_t new)	283	void as_switch(as_t old, as_t new)
281	{	284	{
282	ipl_t ipl;	285	ipl_t ipl;
283	bool needs_asid = false;	286	bool needs_asid = false;
284		287
285	ipl = interrupts_disable();	288	ipl = interrupts_disable();
286	spinlock_lock(&as_lock);	289	spinlock_lock(&as_lock);
287		290
288	/*	291	/*
289	* First, take care of the old address space.	292	* First, take care of the old address space.
290	*/	293	*/
291	if (old) {	294	if (old) {
292	spinlock_lock(&old->lock);	295	spinlock_lock(&old->lock);
293	ASSERT(old->refcount);	296	ASSERT(old->refcount);
294	if((--old->refcount == 0) && (old != AS_KERNEL)) {	297	if((--old->refcount == 0) && (old != AS_KERNEL)) {
295	/*	298	/*
296	* The old address space is no longer active on	299	* The old address space is no longer active on
297	* any processor. It can be appended to the	300	* any processor. It can be appended to the
298	* list of inactive address spaces with assigned	301	* list of inactive address spaces with assigned
299	* ASID.	302	* ASID.
300	*/	303	*/
301	ASSERT(old->asid != ASID_INVALID);	304	ASSERT(old->asid != ASID_INVALID);
302	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);	305	list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head);
303	}	306	}
304	spinlock_unlock(&old->lock);	307	spinlock_unlock(&old->lock);
305	}	308	}
306		309
307	/*	310	/*
308	* Second, prepare the new address space.	311	* Second, prepare the new address space.
309	*/	312	*/
310	spinlock_lock(&new->lock);	313	spinlock_lock(&new->lock);
311	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {	314	if ((new->refcount++ == 0) && (new != AS_KERNEL)) {
312	if (new->asid != ASID_INVALID)	315	if (new->asid != ASID_INVALID)
313	list_remove(&new->inactive_as_with_asid_link);	316	list_remove(&new->inactive_as_with_asid_link);
314	else	317	else
315	needs_asid = true; /* defer call to asid_get() until new->lock is released */	318	needs_asid = true; /* defer call to asid_get() until new->lock is released */
316	}	319	}
317	SET_PTL0_ADDRESS(new->page_table);	320	SET_PTL0_ADDRESS(new->page_table);
318	spinlock_unlock(&new->lock);	321	spinlock_unlock(&new->lock);
319		322
320	if (needs_asid) {	323	if (needs_asid) {
321	/*	324	/*
322	* Allocation of new ASID was deferred	325	* Allocation of new ASID was deferred
323	* until now in order to avoid deadlock.	326	* until now in order to avoid deadlock.
324	*/	327	*/
325	asid_t asid;	328	asid_t asid;
326		329
327	asid = asid_get();	330	asid = asid_get();
328	spinlock_lock(&new->lock);	331	spinlock_lock(&new->lock);
329	new->asid = asid;	332	new->asid = asid;
330	spinlock_unlock(&new->lock);	333	spinlock_unlock(&new->lock);
331	}	334	}
332	spinlock_unlock(&as_lock);	335	spinlock_unlock(&as_lock);
333	interrupts_restore(ipl);	336	interrupts_restore(ipl);
334		337
335	/*	338	/*
336	* Perform architecture-specific steps.	339	* Perform architecture-specific steps.
337	* (e.g. write ASID to hardware register etc.)	340	* (e.g. write ASID to hardware register etc.)
338	*/	341	*/
339	as_install_arch(new);	342	as_install_arch(new);
340		343
341	AS = new;	344	AS = new;
342	}	345	}
343		346
344	/** Compute flags for virtual address translation subsytem.	347	/** Compute flags for virtual address translation subsytem.
345	*	348	*
346	* The address space area must be locked.	349	* The address space area must be locked.
347	* Interrupts must be disabled.	350	* Interrupts must be disabled.
348	*	351	*
349	* @param a Address space area.	352	* @param a Address space area.
350	*	353	*
351	* @return Flags to be used in page_mapping_insert().	354	* @return Flags to be used in page_mapping_insert().
352	*/	355	*/
353	int get_area_flags(as_area_t *a)	356	int get_area_flags(as_area_t *a)
354	{	357	{
355	int flags;	358	int flags;
356		359
357	flags = PAGE_USER \| PAGE_PRESENT;	360	flags = PAGE_USER \| PAGE_PRESENT;
358		361
359	if (a->flags & AS_AREA_READ)	362	if (a->flags & AS_AREA_READ)
360	flags \|= PAGE_READ;	363	flags \|= PAGE_READ;
361		364
362	if (a->flags & AS_AREA_WRITE)	365	if (a->flags & AS_AREA_WRITE)
363	flags \|= PAGE_WRITE;	366	flags \|= PAGE_WRITE;
364		367
365	if (a->flags & AS_AREA_EXEC)	368	if (a->flags & AS_AREA_EXEC)
366	flags \|= PAGE_EXEC;	369	flags \|= PAGE_EXEC;
367		370
368	if (!(a->flags & AS_AREA_DEVICE))	371	if (!(a->flags & AS_AREA_DEVICE))
369	flags \|= PAGE_CACHEABLE;	372	flags \|= PAGE_CACHEABLE;
370		373
371	return flags;	374	return flags;
372	}	375	}
373		376
374	/** Create page table.	377	/** Create page table.
375	*	378	*
376	* Depending on architecture, create either address space	379	* Depending on architecture, create either address space
377	* private or global page table.	380	* private or global page table.
378	*	381	*
379	* @param flags Flags saying whether the page table is for kernel address space.	382	* @param flags Flags saying whether the page table is for kernel address space.
380	*	383	*
381	* @return First entry of the page table.	384	* @return First entry of the page table.
382	*/	385	*/
383	pte_t *page_table_create(int flags)	386	pte_t *page_table_create(int flags)
384	{	387	{
385	ASSERT(as_operations);	388	ASSERT(as_operations);
386	ASSERT(as_operations->page_table_create);	389	ASSERT(as_operations->page_table_create);
387		390
388	return as_operations->page_table_create(flags);	391	return as_operations->page_table_create(flags);
389	}	392	}
390		393
391	/** Lock page table.	394	/** Lock page table.
392	*	395	*
393	* This function should be called before any page_mapping_insert(),	396	* This function should be called before any page_mapping_insert(),
394	* page_mapping_remove() and page_mapping_find().	397	* page_mapping_remove() and page_mapping_find().
395	*	398	*
396	* Locking order is such that address space areas must be locked	399	* Locking order is such that address space areas must be locked
397	* prior to this call. Address space can be locked prior to this	400	* prior to this call. Address space can be locked prior to this
398	* call in which case the lock argument is false.	401	* call in which case the lock argument is false.
399	*	402	*
400	* @param as Address space.	403	* @param as Address space.
401	* @param as_locked If false, do not attempt to lock as->lock.	404	* @param as_locked If false, do not attempt to lock as->lock.
402	*/	405	*/
403	void page_table_lock(as_t *as, bool lock)	406	void page_table_lock(as_t *as, bool lock)
404	{	407	{
405	ASSERT(as_operations);	408	ASSERT(as_operations);
406	ASSERT(as_operations->page_table_lock);	409	ASSERT(as_operations->page_table_lock);
407		410
408	as_operations->page_table_lock(as, lock);	411	as_operations->page_table_lock(as, lock);
409	}	412	}
410		413
411	/** Unlock page table.	414	/** Unlock page table.
412	*	415	*
413	* @param as Address space.	416	* @param as Address space.
414	* @param as_locked If false, do not attempt to unlock as->lock.	417	* @param as_locked If false, do not attempt to unlock as->lock.
415	*/	418	*/
416	void page_table_unlock(as_t *as, bool unlock)	419	void page_table_unlock(as_t *as, bool unlock)
417	{	420	{
418	ASSERT(as_operations);	421	ASSERT(as_operations);
419	ASSERT(as_operations->page_table_unlock);	422	ASSERT(as_operations->page_table_unlock);
420		423
421	as_operations->page_table_unlock(as, unlock);	424	as_operations->page_table_unlock(as, unlock);
422	}	425	}
423		426
424	/** Find address space area and change it.	427	/** Find address space area and change it.
425	*	428	*
426	* @param as Address space.	429	* @param as Address space.
427	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	430	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
428	* @param size New size of the virtual memory block starting at address.	431	* @param size New size of the virtual memory block starting at address.
429	* @param flags Flags influencing the remap operation. Currently unused.	432	* @param flags Flags influencing the remap operation. Currently unused.
430	*	433	*
431	* @return address on success, (__address) -1 otherwise.	434	* @return address on success, (__address) -1 otherwise.
432	*/	435	*/
433	__address as_area_resize(as_t *as, __address address, size_t size, int flags)	436	__address as_area_resize(as_t *as, __address address, size_t size, int flags)
434	{	437	{
435	as_area_t *area = NULL;	438	as_area_t *area = NULL;
436	ipl_t ipl;	439	ipl_t ipl;
437	size_t pages;	440	size_t pages;
438		441
439	ipl = interrupts_disable();	442	ipl = interrupts_disable();
440	spinlock_lock(&as->lock);	443	spinlock_lock(&as->lock);
441		444
442	/*	445	/*
443	* Locate the area.	446	* Locate the area.
444	*/	447	*/
445	area = find_area_and_lock(as, address);	448	area = find_area_and_lock(as, address);
446	if (!area) {	449	if (!area) {
447	spinlock_unlock(&as->lock);	450	spinlock_unlock(&as->lock);
448	interrupts_restore(ipl);	451	interrupts_restore(ipl);
449	return (__address) -1;	452	return (__address) -1;
450	}	453	}
451		454
452	if (area->flags & AS_AREA_DEVICE) {	455	if (area->flags & AS_AREA_DEVICE) {
453	/*	456	/*
454	* Remapping of address space areas associated	457	* Remapping of address space areas associated
455	* with memory mapped devices is not supported.	458	* with memory mapped devices is not supported.
456	*/	459	*/
457	spinlock_unlock(&area->lock);	460	spinlock_unlock(&area->lock);
458	spinlock_unlock(&as->lock);	461	spinlock_unlock(&as->lock);
459	interrupts_restore(ipl);	462	interrupts_restore(ipl);
460	return (__address) -1;	463	return (__address) -1;
461	}	464	}
462		465
463	pages = SIZE2FRAMES((address - area->base) + size);	466	pages = SIZE2FRAMES((address - area->base) + size);
-		467	if (!pages) {
-		468	/*
-		469	* Zero size address space areas are not allowed.
-		470	*/
-		471	spinlock_unlock(&area->lock);
-		472	spinlock_unlock(&as->lock);
-		473	interrupts_restore(ipl);
-		474	return (__address) -1;
-		475	}
-		476
464	if (pages < area->pages) {	477	if (pages < area->pages) {
465	int i;	478	int i;
466		479
467	/*	480	/*
468	* Shrinking the area.	481	* Shrinking the area.
469	* No need to check for overlaps.	482	* No need to check for overlaps.
470	*/	483	*/
471	for (i = pages; i < area->pages; i++) {	484	for (i = pages; i < area->pages; i++) {
472	pte_t *pte;	485	pte_t *pte;
473		486
474	/*	487	/*
475	* Releasing physical memory.	488	* Releasing physical memory.
476	* This depends on the fact that the memory was allocated using frame_alloc().	489	* This depends on the fact that the memory was allocated using frame_alloc().
477	*/	490	*/
478	page_table_lock(as, false);	491	page_table_lock(as, false);
479	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);	492	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
480	if (pte && PTE_VALID(pte)) {	493	if (pte && PTE_VALID(pte)) {
481	__address frame;	494	__address frame;
482		495
483	ASSERT(PTE_PRESENT(pte));	496	ASSERT(PTE_PRESENT(pte));
484	frame = PTE_GET_FRAME(pte);	497	frame = PTE_GET_FRAME(pte);
485	page_mapping_remove(as, area->base + i*PAGE_SIZE);	498	page_mapping_remove(as, area->base + i*PAGE_SIZE);
486	page_table_unlock(as, false);	499	page_table_unlock(as, false);
487		500

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/as.c @ 1227 – Rev 1227 → 1233