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 <synch/spinlock.h>
#include <adt/list.h>
#include <adt/btree.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 <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 memory.
 * @param size Size of area.
 * @param base Base address of area.
 * @param attrs Attributes of the 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, int attrs)
{
    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->attributes = attrs;
    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 dst_id Task ID of the accepting task.
 * @param src_base Base address 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 dst_id, __address src_base)
{
    ipl_t ipl;
    task_t *t;
    count_t i;
    as_t *dst_as;
    __address dst_base;
    int src_flags;
    size_t src_size;
    as_area_t *src_area, *dst_area;
   
    ipl = interrupts_disable();
    spinlock_lock(&tasks_lock);
   
    t = task_find_by_id(dst_id);
    if (!NULL) {
        spinlock_unlock(&tasks_lock);
        interrupts_restore(ipl);
        return ENOENT;
    }
 
    spinlock_lock(&t->lock);
    spinlock_unlock(&tasks_lock);
 
    dst_as = t->as;
    dst_base = (__address) t->accept_arg.base;
   
    if (dst_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;
    }
   
    spinlock_lock(&AS->lock);
    src_area = find_area_and_lock(AS, src_base);
    if (!src_area) {
        /*
         * Could not find the source address space area.
         */
        spinlock_unlock(&t->lock);
        spinlock_unlock(&AS->lock);
        interrupts_restore(ipl);
        return ENOENT;
    }
    src_size = src_area->pages * PAGE_SIZE;
    src_flags = src_area->flags;
    spinlock_unlock(&src_area->lock);
    spinlock_unlock(&AS->lock);
 
    if ((t->accept_arg.task_id != TASK->taskid) || (t->accept_arg.size != src_size) ||
        (t->accept_arg.flags != src_flags)) {
        /*
         * Discrepancy in either task ID, size or flags.
         */
        spinlock_unlock(&t->lock);
        interrupts_restore(ipl);
        return EPERM;
    }
   
    /*
     * Create copy of the source address space area.
     * The destination area is created with AS_AREA_ATTR_PARTIAL
     * attribute set which prevents race condition with
     * preliminary as_page_fault() calls.
     */
    dst_area = as_area_create(dst_as, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL);
    if (!dst_area) {
        /*
         * Destination address space area could not be created.
         */
        spinlock_unlock(&t->lock);
        interrupts_restore(ipl);
        return ENOMEM;
    }
   
 
 
 
 
 
 
 
 
 
 
 
 
    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 (dst_as < AS) {
        spinlock_lock(&dst_as->lock);
        spinlock_lock(&AS->lock);
    } else {
        spinlock_lock(&AS->lock);
        spinlock_lock(&dst_as->lock);
    }
   
    for (i = 0; i < SIZE2FRAMES(src_size); i++) {
        pte_t *pte;
        __address frame;
           
        page_table_lock(AS, false);
        pte = page_mapping_find(AS, src_base + i*PAGE_SIZE);
        if (pte && PTE_VALID(pte)) {
            ASSERT(PTE_PRESENT(pte));
            frame = PTE_GET_FRAME(pte);
            if (!(src_flags & AS_AREA_DEVICE))
                frame_reference_add(ADDR2PFN(frame));
            page_table_unlock(AS, false);
        } else {
            page_table_unlock(AS, false);
            continue;
        }
       
        page_table_lock(dst_as, false);
        page_mapping_insert(dst_as, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags));
        page_table_unlock(dst_as, false);
    }
 
    /*
     * Now the destination address space area has been
     * fully initialized. Clear the AS_AREA_ATTR_PARTIAL
     * attribute.
     */
    spinlock_lock(&dst_area->lock);
    dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
    spinlock_unlock(&dst_area->lock);
   
    spinlock_unlock(&AS->lock);
    spinlock_unlock(&dst_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;
    }
 
    if (area->attributes & AS_AREA_ATTR_PARTIAL) {
        /*
         * The address space area is not fully initialized.
         * Avoid possible race by returning error.
         */
        spinlock_unlock(&area->lock);
        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;
}
 
/** Convert address space area flags to page flags.
 *
 * @param aflags Flags of some address space area.
 *
 * @return Flags to be passed to page_mapping_insert().
 */
int area_flags_to_page_flags(int aflags)
{
    int flags;
 
    flags = PAGE_USER | PAGE_PRESENT;
   
    if (aflags & AS_AREA_READ)
        flags |= PAGE_READ;
       
    if (aflags & AS_AREA_WRITE)
        flags |= PAGE_WRITE;
   
    if (aflags & AS_AREA_EXEC)
        flags |= PAGE_EXEC;
   
    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 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, AS_AREA_ATTR_NONE))
        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);
}
 

Rev 1238	Rev 1239
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 <synch/spinlock.h>	46	#include <synch/spinlock.h>
47	#include <adt/list.h>	47	#include <adt/list.h>
48	#include <adt/btree.h>	48	#include <adt/btree.h>
49	#include <proc/task.h>	49	#include <proc/task.h>
50	#include <arch/asm.h>	50	#include <arch/asm.h>
51	#include <panic.h>	51	#include <panic.h>
52	#include <debug.h>	52	#include <debug.h>
53	#include <print.h>	53	#include <print.h>
54	#include <memstr.h>	54	#include <memstr.h>
55	#include <macros.h>	55	#include <macros.h>
56	#include <arch.h>	56	#include <arch.h>
57	#include <errno.h>	57	#include <errno.h>
58	#include <config.h>	58	#include <config.h>
59	#include <arch/types.h>	59	#include <arch/types.h>
60	#include <typedefs.h>	60	#include <typedefs.h>
61		61
62	as_operations_t *as_operations = NULL;	62	as_operations_t *as_operations = NULL;
63		63
64	/** Address space lock. It protects inactive_as_with_asid_head. */	64	/** Address space lock. It protects inactive_as_with_asid_head. */
65	SPINLOCK_INITIALIZE(as_lock);	65	SPINLOCK_INITIALIZE(as_lock);
66		66
67	/**	67	/**
68	* This list contains address spaces that are not active on any	68	* This list contains address spaces that are not active on any
69	* processor and that have valid ASID.	69	* processor and that have valid ASID.
70	*/	70	*/
71	LIST_INITIALIZE(inactive_as_with_asid_head);	71	LIST_INITIALIZE(inactive_as_with_asid_head);
72		72
73	/** Kernel address space. */	73	/** Kernel address space. */
74	as_t *AS_KERNEL = NULL;	74	as_t *AS_KERNEL = NULL;
75		75
76	static int area_flags_to_page_flags(int aflags);	76	static int area_flags_to_page_flags(int aflags);
77	static int get_area_flags(as_area_t *a);	77	static int get_area_flags(as_area_t *a);
78	static as_area_t find_area_and_lock(as_t as, __address va);	78	static as_area_t find_area_and_lock(as_t as, __address va);
79	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);	79	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);
80		80
81	/** Initialize address space subsystem. */	81	/** Initialize address space subsystem. */
82	void as_init(void)	82	void as_init(void)
83	{	83	{
84	as_arch_init();	84	as_arch_init();
85	AS_KERNEL = as_create(FLAG_AS_KERNEL);	85	AS_KERNEL = as_create(FLAG_AS_KERNEL);
86	if (!AS_KERNEL)	86	if (!AS_KERNEL)
87	panic("can't create kernel address space\n");	87	panic("can't create kernel address space\n");
88	}	88	}
89		89
90	/** Create address space.	90	/** Create address space.
91	*	91	*
92	* @param flags Flags that influence way in wich the address space is created.	92	* @param flags Flags that influence way in wich the address space is created.
93	*/	93	*/
94	as_t *as_create(int flags)	94	as_t *as_create(int flags)
95	{	95	{
96	as_t *as;	96	as_t *as;
97		97
98	as = (as_t *) malloc(sizeof(as_t), 0);	98	as = (as_t *) malloc(sizeof(as_t), 0);
99	link_initialize(&as->inactive_as_with_asid_link);	99	link_initialize(&as->inactive_as_with_asid_link);
100	spinlock_initialize(&as->lock, "as_lock");	100	spinlock_initialize(&as->lock, "as_lock");
101	btree_create(&as->as_area_btree);	101	btree_create(&as->as_area_btree);
102		102
103	if (flags & FLAG_AS_KERNEL)	103	if (flags & FLAG_AS_KERNEL)
104	as->asid = ASID_KERNEL;	104	as->asid = ASID_KERNEL;
105	else	105	else
106	as->asid = ASID_INVALID;	106	as->asid = ASID_INVALID;
107		107
108	as->refcount = 0;	108	as->refcount = 0;
109	as->page_table = page_table_create(flags);	109	as->page_table = page_table_create(flags);
110		110
111	return as;	111	return as;
112	}	112	}
113		113
114	/** Free Adress space */	114	/** Free Adress space */
115	void as_free(as_t *as)	115	void as_free(as_t *as)
116	{	116	{
117	ASSERT(as->refcount == 0);	117	ASSERT(as->refcount == 0);
118		118
119	/* TODO: free as_areas and other resources held by as */	119	/* TODO: free as_areas and other resources held by as */
120	/* TODO: free page table */	120	/* TODO: free page table */
121	free(as);	121	free(as);
122	}	122	}
123		123
124	/** Create address space area of common attributes.	124	/** Create address space area of common attributes.
125	*	125	*
126	* The created address space area is added to the target address space.	126	* The created address space area is added to the target address space.
127	*	127	*
128	* @param as Target address space.	128	* @param as Target address space.
129	* @param flags Flags of the area.	129	* @param flags Flags of the area memory.
130	* @param size Size of area.	130	* @param size Size of area.
131	* @param base Base address of area.	131	* @param base Base address of area.
-		132	* @param attrs Attributes of the area.
132	*	133	*
133	* @return Address space area on success or NULL on failure.	134	* @return Address space area on success or NULL on failure.
134	*/	135	*/
135	as_area_t as_area_create(as_t as, int flags, size_t size, __address base)	136	as_area_t as_area_create(as_t as, int flags, size_t size, __address base, int attrs)
136	{	137	{
137	ipl_t ipl;	138	ipl_t ipl;
138	as_area_t *a;	139	as_area_t *a;
139		140
140	if (base % PAGE_SIZE)	141	if (base % PAGE_SIZE)
141	return NULL;	142	return NULL;
142		143
143	if (!size)	144	if (!size)
144	return NULL;	145	return NULL;
145		146
146	/* Writeable executable areas are not supported. */	147	/* Writeable executable areas are not supported. */
147	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))	148	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
148	return NULL;	149	return NULL;
149		150
150	ipl = interrupts_disable();	151	ipl = interrupts_disable();
151	spinlock_lock(&as->lock);	152	spinlock_lock(&as->lock);
152		153
153	if (!check_area_conflicts(as, base, size, NULL)) {	154	if (!check_area_conflicts(as, base, size, NULL)) {
154	spinlock_unlock(&as->lock);	155	spinlock_unlock(&as->lock);
155	interrupts_restore(ipl);	156	interrupts_restore(ipl);
156	return NULL;	157	return NULL;
157	}	158	}
158		159
159	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	160	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
160		161
161	spinlock_initialize(&a->lock, "as_area_lock");	162	spinlock_initialize(&a->lock, "as_area_lock");
162		163
163	a->flags = flags;	164	a->flags = flags;
-		165	a->attributes = attrs;
164	a->pages = SIZE2FRAMES(size);	166	a->pages = SIZE2FRAMES(size);
165	a->base = base;	167	a->base = base;
166		168
167	btree_insert(&as->as_area_btree, base, (void *) a, NULL);	169	btree_insert(&as->as_area_btree, base, (void *) a, NULL);
168		170
169	spinlock_unlock(&as->lock);	171	spinlock_unlock(&as->lock);
170	interrupts_restore(ipl);	172	interrupts_restore(ipl);
171		173
172	return a;	174	return a;
173	}	175	}
174		176
175	/** Find address space area and change it.	177	/** Find address space area and change it.
176	*	178	*
177	* @param as Address space.	179	* @param as Address space.
178	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	180	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
179	* @param size New size of the virtual memory block starting at address.	181	* @param size New size of the virtual memory block starting at address.
180	* @param flags Flags influencing the remap operation. Currently unused.	182	* @param flags Flags influencing the remap operation. Currently unused.
181	*	183	*
182	* @return address on success, (__address) -1 otherwise.	184	* @return address on success, (__address) -1 otherwise.
183	*/	185	*/
184	__address as_area_resize(as_t *as, __address address, size_t size, int flags)	186	__address as_area_resize(as_t *as, __address address, size_t size, int flags)
185	{	187	{
186	as_area_t *area = NULL;	188	as_area_t *area = NULL;
187	ipl_t ipl;	189	ipl_t ipl;
188	size_t pages;	190	size_t pages;
189		191
190	ipl = interrupts_disable();	192	ipl = interrupts_disable();
191	spinlock_lock(&as->lock);	193	spinlock_lock(&as->lock);
192		194
193	/*	195	/*
194	* Locate the area.	196	* Locate the area.
195	*/	197	*/
196	area = find_area_and_lock(as, address);	198	area = find_area_and_lock(as, address);
197	if (!area) {	199	if (!area) {
198	spinlock_unlock(&as->lock);	200	spinlock_unlock(&as->lock);
199	interrupts_restore(ipl);	201	interrupts_restore(ipl);
200	return (__address) -1;	202	return (__address) -1;
201	}	203	}
202		204
203	if (area->flags & AS_AREA_DEVICE) {	205	if (area->flags & AS_AREA_DEVICE) {
204	/*	206	/*
205	* Remapping of address space areas associated	207	* Remapping of address space areas associated
206	* with memory mapped devices is not supported.	208	* with memory mapped devices is not supported.
207	*/	209	*/
208	spinlock_unlock(&area->lock);	210	spinlock_unlock(&area->lock);
209	spinlock_unlock(&as->lock);	211	spinlock_unlock(&as->lock);
210	interrupts_restore(ipl);	212	interrupts_restore(ipl);
211	return (__address) -1;	213	return (__address) -1;
212	}	214	}
213		215
214	pages = SIZE2FRAMES((address - area->base) + size);	216	pages = SIZE2FRAMES((address - area->base) + size);
215	if (!pages) {	217	if (!pages) {
216	/*	218	/*
217	* Zero size address space areas are not allowed.	219	* Zero size address space areas are not allowed.
218	*/	220	*/
219	spinlock_unlock(&area->lock);	221	spinlock_unlock(&area->lock);
220	spinlock_unlock(&as->lock);	222	spinlock_unlock(&as->lock);
221	interrupts_restore(ipl);	223	interrupts_restore(ipl);
222	return (__address) -1;	224	return (__address) -1;
223	}	225	}
224		226
225	if (pages < area->pages) {	227	if (pages < area->pages) {
226	int i;	228	int i;
227		229
228	/*	230	/*
229	* Shrinking the area.	231	* Shrinking the area.
230	* No need to check for overlaps.	232	* No need to check for overlaps.
231	*/	233	*/
232	for (i = pages; i < area->pages; i++) {	234	for (i = pages; i < area->pages; i++) {
233	pte_t *pte;	235	pte_t *pte;
234		236
235	/*	237	/*
236	* Releasing physical memory.	238	* Releasing physical memory.
237	* This depends on the fact that the memory was allocated using frame_alloc().	239	* This depends on the fact that the memory was allocated using frame_alloc().
238	*/	240	*/
239	page_table_lock(as, false);	241	page_table_lock(as, false);
240	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);	242	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
241	if (pte && PTE_VALID(pte)) {	243	if (pte && PTE_VALID(pte)) {
242	__address frame;	244	__address frame;
243		245
244	ASSERT(PTE_PRESENT(pte));	246	ASSERT(PTE_PRESENT(pte));
245	frame = PTE_GET_FRAME(pte);	247	frame = PTE_GET_FRAME(pte);
246	page_mapping_remove(as, area->base + i*PAGE_SIZE);	248	page_mapping_remove(as, area->base + i*PAGE_SIZE);
247	page_table_unlock(as, false);	249	page_table_unlock(as, false);
248		250
249	frame_free(ADDR2PFN(frame));	251	frame_free(ADDR2PFN(frame));
250	} else {	252	} else {
251	page_table_unlock(as, false);	253	page_table_unlock(as, false);
252	}	254	}
253	}	255	}
254	/*	256	/*
255	* Invalidate TLB's.	257	* Invalidate TLB's.
256	*/	258	*/
257	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	259	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
258	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	260	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
259	tlb_shootdown_finalize();	261	tlb_shootdown_finalize();
260	} else {	262	} else {
261	/*	263	/*
262	* Growing the area.	264	* Growing the area.
263	* Check for overlaps with other address space areas.	265	* Check for overlaps with other address space areas.
264	*/	266	*/
265	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {	267	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
266	spinlock_unlock(&area->lock);	268	spinlock_unlock(&area->lock);
267	spinlock_unlock(&as->lock);	269	spinlock_unlock(&as->lock);
268	interrupts_restore(ipl);	270	interrupts_restore(ipl);
269	return (__address) -1;	271	return (__address) -1;
270	}	272	}
271	}	273	}
272		274
273	area->pages = pages;	275	area->pages = pages;
274		276
275	spinlock_unlock(&area->lock);	277	spinlock_unlock(&area->lock);
276	spinlock_unlock(&as->lock);	278	spinlock_unlock(&as->lock);
277	interrupts_restore(ipl);	279	interrupts_restore(ipl);
278		280
279	return address;	281	return address;
280	}	282	}
281		283
282	/** Send address space area to another task.	284	/** Send address space area to another task.
283	*	285	*
284	* Address space area is sent to the specified task.	286	* Address space area is sent to the specified task.
285	* If the destination task is willing to accept the	287	* If the destination task is willing to accept the
286	* area, a new area is created according to the	288	* area, a new area is created according to the
287	* source area. Moreover, any existing mapping	289	* source area. Moreover, any existing mapping
288	* is copied as well, providing thus a mechanism	290	* is copied as well, providing thus a mechanism
289	* for sharing group of pages. The source address	291	* for sharing group of pages. The source address
290	* space area and any associated mapping is preserved.	292	* space area and any associated mapping is preserved.
291	*	293	*
292	* @param id Task ID of the accepting task.	294	* @param dst_id Task ID of the accepting task.
293	* @param base Base address of the source address space area.	295	* @param src_base Base address of the source address space area.
294	*	296	*
295	* @return 0 on success or ENOENT if there is no such task or	297	* @return 0 on success or ENOENT if there is no such task or
296	* if there is no such address space area,	298	* if there is no such address space area,
297	* EPERM if there was a problem in accepting the area or	299	* EPERM if there was a problem in accepting the area or
298	* ENOMEM if there was a problem in allocating destination	300	* ENOMEM if there was a problem in allocating destination
299	* address space area.	301	* address space area.
300	*/	302	*/
301	int as_area_send(task_id_t id, __address base)	303	int as_area_send(task_id_t dst_id, __address src_base)
302	{	304	{
303	ipl_t ipl;	305	ipl_t ipl;
304	task_t *t;	306	task_t *t;
305	count_t i;	307	count_t i;
306	as_t *as;	308	as_t *dst_as;
307	__address dst_base;	309	__address dst_base;
308	int flags;	310	int src_flags;
309	size_t size;	311	size_t src_size;
310	as_area_t *area;	312	as_area_t src_area, dst_area;
311		313
312	ipl = interrupts_disable();	314	ipl = interrupts_disable();
313	spinlock_lock(&tasks_lock);	315	spinlock_lock(&tasks_lock);
314		316
315	t = task_find_by_id(id);	317	t = task_find_by_id(dst_id);
316	if (!NULL) {	318	if (!NULL) {
317	spinlock_unlock(&tasks_lock);	319	spinlock_unlock(&tasks_lock);
318	interrupts_restore(ipl);	320	interrupts_restore(ipl);
319	return ENOENT;	321	return ENOENT;
320	}	322	}
321		323
322	spinlock_lock(&t->lock);	324	spinlock_lock(&t->lock);
323	spinlock_unlock(&tasks_lock);	325	spinlock_unlock(&tasks_lock);
324		326
325	as = t->as;	327	dst_as = t->as;
326	dst_base = (__address) t->accept_arg.base;	328	dst_base = (__address) t->accept_arg.base;
327		329
328	if (as == AS) {	330	if (dst_as == AS) {
329	/*	331	/*
330	* The two tasks share the entire address space.	332	* The two tasks share the entire address space.
331	* Return error since there is no point in continuing.	333	* Return error since there is no point in continuing.
332	*/	334	*/
333	spinlock_unlock(&t->lock);	335	spinlock_unlock(&t->lock);
334	interrupts_restore(ipl);	336	interrupts_restore(ipl);
335	return EPERM;	337	return EPERM;
336	}	338	}
337		339
338	spinlock_lock(&AS->lock);	340	spinlock_lock(&AS->lock);
339	area = find_area_and_lock(AS, base);	341	src_area = find_area_and_lock(AS, src_base);
340	if (!area) {	342	if (!src_area) {
341	/*	343	/*
342	* Could not find the source address space area.	344	* Could not find the source address space area.
343	*/	345	*/
344	spinlock_unlock(&t->lock);	346	spinlock_unlock(&t->lock);
345	spinlock_unlock(&AS->lock);	347	spinlock_unlock(&AS->lock);
346	interrupts_restore(ipl);	348	interrupts_restore(ipl);
347	return ENOENT;	349	return ENOENT;
348	}	350	}
349	size = area->pages * PAGE_SIZE;	351	src_size = src_area->pages * PAGE_SIZE;
350	flags = area->flags;	352	src_flags = src_area->flags;
351	spinlock_unlock(&area->lock);	353	spinlock_unlock(&src_area->lock);
352	spinlock_unlock(&AS->lock);	354	spinlock_unlock(&AS->lock);
353		355
354	if ((t->accept_arg.task_id != TASK->taskid) \|\| (t->accept_arg.size != size) \|\|	356	if ((t->accept_arg.task_id != TASK->taskid) \|\| (t->accept_arg.size != src_size) \|\|
355	(t->accept_arg.flags != flags)) {	357	(t->accept_arg.flags != src_flags)) {
356	/*	358	/*
357	* Discrepancy in either task ID, size or flags.	359	* Discrepancy in either task ID, size or flags.
358	*/	360	*/
359	spinlock_unlock(&t->lock);	361	spinlock_unlock(&t->lock);
360	interrupts_restore(ipl);	362	interrupts_restore(ipl);
361	return EPERM;	363	return EPERM;
362	}	364	}
363		365
364	/*	366	/*
365	* Create copy of the address space area.	367	* Create copy of the source address space area.
-		368	* The destination area is created with AS_AREA_ATTR_PARTIAL
-		369	* attribute set which prevents race condition with
-		370	* preliminary as_page_fault() calls.
366	*/	371	*/
367	if (!as_area_create(as, flags, size, dst_base)) {	372	dst_area = as_area_create(dst_as, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL);
-		373	if (!dst_area) {
368	/*	374	/*
369	* Destination address space area could not be created.	375	* Destination address space area could not be created.
370	*/	376	*/
371	spinlock_unlock(&t->lock);	377	spinlock_unlock(&t->lock);
372	interrupts_restore(ipl);	378	interrupts_restore(ipl);
373	return ENOMEM;	379	return ENOMEM;
374	}	380	}
375		381
376	/*	-
377	* NOTE: we have just introduced a race condition.	-
378	* The destination task can try to attempt the newly	-
379	* created area before its mapping is copied from	-
380	* the source address space area. In result, frames	-
381	* can get lost.	-
382	*	-
383	* Currently, this race is not solved, but one of the	-
384	* possible solutions would be to sleep in as_page_fault()	-
385	* when this situation is detected.	-
386	*/	-
387		-
388	memsetb((__address) &t->accept_arg, sizeof(as_area_acptsnd_arg_t), 0);	382	memsetb((__address) &t->accept_arg, sizeof(as_area_acptsnd_arg_t), 0);
389	spinlock_unlock(&t->lock);	383	spinlock_unlock(&t->lock);
390		384
391	/*	385	/*
392	* Avoid deadlock by first locking the address space with lower address.	386	* Avoid deadlock by first locking the address space with lower address.
393	*/	387	*/
394	if (as < AS) {	388	if (dst_as < AS) {
395	spinlock_lock(&as->lock);	389	spinlock_lock(&dst_as->lock);
396	spinlock_lock(&AS->lock);	390	spinlock_lock(&AS->lock);
397	} else {	391	} else {
398	spinlock_lock(&AS->lock);	392	spinlock_lock(&AS->lock);
399	spinlock_lock(&as->lock);	393	spinlock_lock(&dst_as->lock);
400	}	394	}
401		395
402	for (i = 0; i < SIZE2FRAMES(size); i++) {	396	for (i = 0; i < SIZE2FRAMES(src_size); i++) {
403	pte_t *pte;	397	pte_t *pte;
404	__address frame;	398	__address frame;
405		399
406	page_table_lock(AS, false);	400	page_table_lock(AS, false);
407	pte = page_mapping_find(AS, base + i*PAGE_SIZE);	401	pte = page_mapping_find(AS, src_base + i*PAGE_SIZE);
408	if (pte && PTE_VALID(pte)) {	402	if (pte && PTE_VALID(pte)) {
409	ASSERT(PTE_PRESENT(pte));	403	ASSERT(PTE_PRESENT(pte));
410	frame = PTE_GET_FRAME(pte);	404	frame = PTE_GET_FRAME(pte);
411	if (!(flags & AS_AREA_DEVICE))	405	if (!(src_flags & AS_AREA_DEVICE))
412	frame_reference_add(ADDR2PFN(frame));	406	frame_reference_add(ADDR2PFN(frame));
413	page_table_unlock(AS, false);	407	page_table_unlock(AS, false);
414	} else {	408	} else {
415	page_table_unlock(AS, false);	409	page_table_unlock(AS, false);
416	continue;	410	continue;
417	}	411	}
418		412
419	page_table_lock(as, false);	413	page_table_lock(dst_as, false);
420	page_mapping_insert(as, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(flags));	414	page_mapping_insert(dst_as, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags));
421	page_table_unlock(as, false);	415	page_table_unlock(dst_as, false);
422	}	416	}
-		417
-		418	/*
-		419	* Now the destination address space area has been
-		420	* fully initialized. Clear the AS_AREA_ATTR_PARTIAL
-		421	* attribute.
-		422	*/
-		423	spinlock_lock(&dst_area->lock);
-		424	dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
-		425	spinlock_unlock(&dst_area->lock);
423		426
424	spinlock_unlock(&AS->lock);	427	spinlock_unlock(&AS->lock);
425	spinlock_unlock(&as->lock);	428	spinlock_unlock(&dst_as->lock);
426	interrupts_restore(ipl);	429	interrupts_restore(ipl);
427		430
428	return 0;	431	return 0;
429	}	432	}
430		433
431	/** Initialize mapping for one page of address space.	434	/** Initialize mapping for one page of address space.
432	*	435	*
433	* This functions maps 'page' to 'frame' according	436	* This functions maps 'page' to 'frame' according
434	* to attributes of the address space area to	437	* to attributes of the address space area to
435	* wich 'page' belongs.	438	* wich 'page' belongs.
436	*	439	*
437	* @param as Target address space.	440	* @param as Target address space.
438	* @param page Virtual page within the area.	441	* @param page Virtual page within the area.
439	* @param frame Physical frame to which page will be mapped.	442	* @param frame Physical frame to which page will be mapped.
440	*/	443	*/
441	void as_set_mapping(as_t *as, __address page, __address frame)	444	void as_set_mapping(as_t *as, __address page, __address frame)
442	{	445	{
443	as_area_t *area;	446	as_area_t *area;
444	ipl_t ipl;	447	ipl_t ipl;
445		448
446	ipl = interrupts_disable();	449	ipl = interrupts_disable();
447	page_table_lock(as, true);	450	page_table_lock(as, true);
448		451
449	area = find_area_and_lock(as, page);	452	area = find_area_and_lock(as, page);
450	if (!area) {	453	if (!area) {
451	panic("page not part of any as_area\n");	454	panic("page not part of any as_area\n");
452	}	455	}
453		456
454	page_mapping_insert(as, page, frame, get_area_flags(area));	457	page_mapping_insert(as, page, frame, get_area_flags(area));
455		458
456	spinlock_unlock(&area->lock);	459	spinlock_unlock(&area->lock);
457	page_table_unlock(as, true);	460	page_table_unlock(as, true);
458	interrupts_restore(ipl);	461	interrupts_restore(ipl);
459	}	462	}
460		463
461	/** Handle page fault within the current address space.	464	/** Handle page fault within the current address space.
462	*	465	*
463	* This is the high-level page fault handler.	466	* This is the high-level page fault handler.
464	* Interrupts are assumed disabled.	467	* Interrupts are assumed disabled.
465	*	468	*
466	* @param page Faulting page.	469	* @param page Faulting page.
467	*	470	*
468	* @return 0 on page fault, 1 on success.	471	* @return 0 on page fault, 1 on success.
469	*/	472	*/
470	int as_page_fault(__address page)	473	int as_page_fault(__address page)
471	{	474	{
472	pte_t *pte;	475	pte_t *pte;
473	as_area_t *area;	476	as_area_t *area;
474	__address frame;	477	__address frame;
475		478
476	ASSERT(AS);	479	ASSERT(AS);
477		480
478	spinlock_lock(&AS->lock);	481	spinlock_lock(&AS->lock);
479	area = find_area_and_lock(AS, page);	482	area = find_area_and_lock(AS, page);
480	if (!area) {	483	if (!area) {
481	/*	484	/*
482	* No area contained mapping for 'page'.	485	* No area contained mapping for 'page'.
483	* Signal page fault to low-level handler.	486	* Signal page fault to low-level handler.
484	*/	487	*/
485	spinlock_unlock(&AS->lock);	488	spinlock_unlock(&AS->lock);

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(root)/kernel/trunk/generic/src/mm/as.c – Rev 1238 → 1239