WebSVN – HelenOS – Diff – /tags/0.1.1/kernel/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.
 */
 
/**
 * @file    as.c
 * @brief   Address space related functions.
 *
 * This file contains address space manipulation functions.
 * Roughly speaking, this is a higher-level client of
 * Virtual Address Translation (VAT) subsystem.
 *
 * Functionality provided by this file allows one to
 * create address space and create, resize and share
 * address space areas.
 *
 * @see page.c
 *
 */
 
#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 <proc/thread.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>
#include <syscall/copy.h>
#include <arch/interrupt.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 Zero on success or a value from @ref errno.h otherwise.
 */
int as_area_resize(as_t *as, __address address, size_t size, int flags)
{
    as_area_t *area;
    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 ENOENT;
    }
 
    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 ENOTSUP;
    }
 
    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 EPERM;
    }
   
    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 EADDRNOTAVAIL;
        }
    }
 
    area->pages = pages;
   
    spinlock_unlock(&area->lock);
    spinlock_unlock(&as->lock);
    interrupts_restore(ipl);
 
    return 0;
}
 
/** Destroy address space area.
 *
 * @param as Address space.
 * @param address Address withing the area to be deleted.
 *
 * @return Zero on success or a value from @ref errno.h on failure.
 */
int as_area_destroy(as_t *as, __address address)
{
    as_area_t *area;
    __address base;
    ipl_t ipl;
    int i;
 
    ipl = interrupts_disable();
    spinlock_lock(&as->lock);
 
    area = find_area_and_lock(as, address);
    if (!area) {
        spinlock_unlock(&as->lock);
        interrupts_restore(ipl);
        return ENOENT;
    }
 
    base = area->base; 
    for (i = 0; i < area->pages; i++) {
        pte_t *pte;
 
        /*
         * Releasing physical memory.
         * Areas mapping memory-mapped devices are treated differently than
         * areas backing frame_alloc()'ed memory.
         */
        page_table_lock(as, false);
        pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
        if (pte && PTE_VALID(pte)) {
            ASSERT(PTE_PRESENT(pte));
            page_mapping_remove(as, area->base + i*PAGE_SIZE);
            if (area->flags & AS_AREA_DEVICE) {
                __address frame;
                frame = PTE_GET_FRAME(pte);
                frame_free(ADDR2PFN(frame));
            }
            page_table_unlock(as, false);
        } else {
            page_table_unlock(as, false);
        }
    }
    /*
     * Invalidate TLB's.
     */
    tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);
    tlb_invalidate_pages(AS->asid, area->base, area->pages);
    tlb_shootdown_finalize();
 
    area->attributes |= AS_AREA_ATTR_PARTIAL;
    spinlock_unlock(&area->lock);
 
    /*
     * Remove the empty area from address space.
     */
    btree_remove(&AS->as_area_btree, base, NULL);
   
    free(area);
   
    spinlock_unlock(&AS->lock);
    interrupts_restore(ipl);
    return 0;
}
 
/** Steal address space area from another task.
 *
 * Address space area is stolen from another task
 * 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 src_task Pointer of source task
 * @param src_base Base address of the source address space area.
 * @param acc_size Expected size of the source area
 * @param dst_base Target base address
 *
 * @return Zero 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_steal(task_t *src_task, __address src_base, size_t acc_size,
          __address dst_base)
{
    ipl_t ipl;
    count_t i;
    as_t *src_as;      
    int src_flags;
    size_t src_size;
    as_area_t *src_area, *dst_area;
 
    ipl = interrupts_disable();
    spinlock_lock(&src_task->lock);
    src_as = src_task->as;
   
    spinlock_lock(&src_as->lock);
    src_area = find_area_and_lock(src_as, src_base);
    if (!src_area) {
        /*
         * Could not find the source address space area.
         */
        spinlock_unlock(&src_task->lock);
        spinlock_unlock(&src_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(&src_as->lock);
 
 
    if (src_size != acc_size) {
        spinlock_unlock(&src_task->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(AS, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL);
    if (!dst_area) {
        /*
         * Destination address space area could not be created.
         */
        spinlock_unlock(&src_task->lock);
        interrupts_restore(ipl);
        return ENOMEM;
    }
   
    spinlock_unlock(&src_task->lock);
   
    /*
     * Avoid deadlock by first locking the address space with lower address.
     */
    if (AS < src_as) {
        spinlock_lock(&AS->lock);
        spinlock_lock(&src_as->lock);
    } else {
        spinlock_lock(&AS->lock);
        spinlock_lock(&src_as->lock);
    }
   
    for (i = 0; i < SIZE2FRAMES(src_size); i++) {
        pte_t *pte;
        __address frame;
           
        page_table_lock(src_as, false);
        pte = page_mapping_find(src_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(src_as, false);
        } else {
            page_table_unlock(src_as, false);
            continue;
        }
       
        page_table_lock(AS, false);
        page_mapping_insert(AS, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags));
        page_table_unlock(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(&src_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.
 * @param istate Pointer to interrupted state.
 *
 * @return 0 on page fault, 1 on success or 2 if the fault was caused by copy_to_uspace() or copy_from_uspace().
 */
int as_page_fault(__address page, istate_t *istate)
{
    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);
        goto page_fault;
    }
 
    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);
        goto page_fault;       
    }
 
    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 AS_PF_OK;
 
page_fault:
    if (!THREAD)
        return AS_PF_FAULT;
   
    if (THREAD->in_copy_from_uspace) {
        THREAD->in_copy_from_uspace = false;
        istate_set_retaddr(istate, (__address) &memcpy_from_uspace_failover_address);
    } else if (THREAD->in_copy_to_uspace) {
        THREAD->in_copy_to_uspace = false;
        istate_set_retaddr(istate, (__address) &memcpy_to_uspace_failover_address);
    } else {
        return AS_PF_FAULT;
    }
 
    return AS_PF_DEFER;
}
 
/** 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 lock 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 unlock 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;
}
 
/** Return size of address space of current task pointed to by base */
size_t as_get_size(__address base)
{
    ipl_t ipl;
    as_area_t *src_area;
    size_t size;
 
    ipl = interrupts_disable();
    src_area = find_area_and_lock(AS, base);
    if (src_area){
        size = src_area->pages * PAGE_SIZE;
        spinlock_unlock(&src_area->lock);
    } else {
        size = 0;
    }
    interrupts_restore(ipl);
    return size;
}
 
/*
 * 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 (__native) as_area_resize(AS, address, size, 0);
}
 
/** Wrapper for as_area_destroy. */
__native sys_as_area_destroy(__address address)
{
    return (__native) as_area_destroy(AS, address);
}
 
 

Rev 1963	Rev 1968
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	* @file as.c	30	* @file as.c
31	* @brief Address space related functions.	31	* @brief Address space related functions.
32	*	32	*
33	* This file contains address space manipulation functions.	33	* This file contains address space manipulation functions.
34	* Roughly speaking, this is a higher-level client of	34	* Roughly speaking, this is a higher-level client of
35	* Virtual Address Translation (VAT) subsystem.	35	* Virtual Address Translation (VAT) subsystem.
36	*	36	*
37	* Functionality provided by this file allows one to	37	* Functionality provided by this file allows one to
38	* create address space and create, resize and share	38	* create address space and create, resize and share
39	* address space areas.	39	* address space areas.
40	*	40	*
41	* @see page.c	41	* @see page.c
42	*	42	*
43	*/	43	*/
44		44
45	#include <mm/as.h>	45	#include <mm/as.h>
46	#include <arch/mm/as.h>	46	#include <arch/mm/as.h>
47	#include <mm/page.h>	47	#include <mm/page.h>
48	#include <mm/frame.h>	48	#include <mm/frame.h>
49	#include <mm/slab.h>	49	#include <mm/slab.h>
50	#include <mm/tlb.h>	50	#include <mm/tlb.h>
51	#include <arch/mm/page.h>	51	#include <arch/mm/page.h>
52	#include <genarch/mm/page_pt.h>	52	#include <genarch/mm/page_pt.h>
53	#include <genarch/mm/page_ht.h>	53	#include <genarch/mm/page_ht.h>
54	#include <mm/asid.h>	54	#include <mm/asid.h>
55	#include <arch/mm/asid.h>	55	#include <arch/mm/asid.h>
56	#include <synch/spinlock.h>	56	#include <synch/spinlock.h>
57	#include <adt/list.h>	57	#include <adt/list.h>
58	#include <adt/btree.h>	58	#include <adt/btree.h>
59	#include <proc/task.h>	59	#include <proc/task.h>
60	#include <proc/thread.h>	60	#include <proc/thread.h>
61	#include <arch/asm.h>	61	#include <arch/asm.h>
62	#include <panic.h>	62	#include <panic.h>
63	#include <debug.h>	63	#include <debug.h>
64	#include <print.h>	64	#include <print.h>
65	#include <memstr.h>	65	#include <memstr.h>
66	#include <macros.h>	66	#include <macros.h>
67	#include <arch.h>	67	#include <arch.h>
68	#include <errno.h>	68	#include <errno.h>
69	#include <config.h>	69	#include <config.h>
70	#include <arch/types.h>	70	#include <arch/types.h>
71	#include <typedefs.h>	71	#include <typedefs.h>
72	#include <syscall/copy.h>	72	#include <syscall/copy.h>
73	#include <arch/interrupt.h>	73	#include <arch/interrupt.h>
74		74
75	as_operations_t *as_operations = NULL;	75	as_operations_t *as_operations = NULL;
76		76
77	/** Address space lock. It protects inactive_as_with_asid_head. */	77	/** Address space lock. It protects inactive_as_with_asid_head. */
78	SPINLOCK_INITIALIZE(as_lock);	78	SPINLOCK_INITIALIZE(as_lock);
79		79
80	/**	80	/**
81	* This list contains address spaces that are not active on any	81	* This list contains address spaces that are not active on any
82	* processor and that have valid ASID.	82	* processor and that have valid ASID.
83	*/	83	*/
84	LIST_INITIALIZE(inactive_as_with_asid_head);	84	LIST_INITIALIZE(inactive_as_with_asid_head);
85		85
86	/** Kernel address space. */	86	/** Kernel address space. */
87	as_t *AS_KERNEL = NULL;	87	as_t *AS_KERNEL = NULL;
88		88
89	static int area_flags_to_page_flags(int aflags);	89	static int area_flags_to_page_flags(int aflags);
90	static int get_area_flags(as_area_t *a);	90	static int get_area_flags(as_area_t *a);
91	static as_area_t find_area_and_lock(as_t as, __address va);	91	static as_area_t find_area_and_lock(as_t as, __address va);
92	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);	92	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);
93		93
94	/** Initialize address space subsystem. */	94	/** Initialize address space subsystem. */
95	void as_init(void)	95	void as_init(void)
96	{	96	{
97	as_arch_init();	97	as_arch_init();
98	AS_KERNEL = as_create(FLAG_AS_KERNEL);	98	AS_KERNEL = as_create(FLAG_AS_KERNEL);
99	if (!AS_KERNEL)	99	if (!AS_KERNEL)
100	panic("can't create kernel address space\n");	100	panic("can't create kernel address space\n");
101	}	101	}
102		102
103	/** Create address space.	103	/** Create address space.
104	*	104	*
105	* @param flags Flags that influence way in wich the address space is created.	105	* @param flags Flags that influence way in wich the address space is created.
106	*/	106	*/
107	as_t *as_create(int flags)	107	as_t *as_create(int flags)
108	{	108	{
109	as_t *as;	109	as_t *as;
110		110
111	as = (as_t *) malloc(sizeof(as_t), 0);	111	as = (as_t *) malloc(sizeof(as_t), 0);
112	link_initialize(&as->inactive_as_with_asid_link);	112	link_initialize(&as->inactive_as_with_asid_link);
113	spinlock_initialize(&as->lock, "as_lock");	113	spinlock_initialize(&as->lock, "as_lock");
114	btree_create(&as->as_area_btree);	114	btree_create(&as->as_area_btree);
115		115
116	if (flags & FLAG_AS_KERNEL)	116	if (flags & FLAG_AS_KERNEL)
117	as->asid = ASID_KERNEL;	117	as->asid = ASID_KERNEL;
118	else	118	else
119	as->asid = ASID_INVALID;	119	as->asid = ASID_INVALID;
120		120
121	as->refcount = 0;	121	as->refcount = 0;
122	as->page_table = page_table_create(flags);	122	as->page_table = page_table_create(flags);
123		123
124	return as;	124	return as;
125	}	125	}
126		126
127	/** Free Adress space */	127	/** Free Adress space */
128	void as_free(as_t *as)	128	void as_free(as_t *as)
129	{	129	{
130	ASSERT(as->refcount == 0);	130	ASSERT(as->refcount == 0);
131		131
132	/* TODO: free as_areas and other resources held by as */	132	/* TODO: free as_areas and other resources held by as */
133	/* TODO: free page table */	133	/* TODO: free page table */
134	free(as);	134	free(as);
135	}	135	}
136		136
137	/** Create address space area of common attributes.	137	/** Create address space area of common attributes.
138	*	138	*
139	* The created address space area is added to the target address space.	139	* The created address space area is added to the target address space.
140	*	140	*
141	* @param as Target address space.	141	* @param as Target address space.
142	* @param flags Flags of the area memory.	142	* @param flags Flags of the area memory.
143	* @param size Size of area.	143	* @param size Size of area.
144	* @param base Base address of area.	144	* @param base Base address of area.
145	* @param attrs Attributes of the area.	145	* @param attrs Attributes of the area.
146	*	146	*
147	* @return Address space area on success or NULL on failure.	147	* @return Address space area on success or NULL on failure.
148	*/	148	*/
149	as_area_t as_area_create(as_t as, int flags, size_t size, __address base, int attrs)	149	as_area_t as_area_create(as_t as, int flags, size_t size, __address base, int attrs)
150	{	150	{
151	ipl_t ipl;	151	ipl_t ipl;
152	as_area_t *a;	152	as_area_t *a;
153		153
154	if (base % PAGE_SIZE)	154	if (base % PAGE_SIZE)
155	return NULL;	155	return NULL;
156		156
157	if (!size)	157	if (!size)
158	return NULL;	158	return NULL;
159		159
160	/* Writeable executable areas are not supported. */	160	/* Writeable executable areas are not supported. */
161	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))	161	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
162	return NULL;	162	return NULL;
163		163
164	ipl = interrupts_disable();	164	ipl = interrupts_disable();
165	spinlock_lock(&as->lock);	165	spinlock_lock(&as->lock);
166		166
167	if (!check_area_conflicts(as, base, size, NULL)) {	167	if (!check_area_conflicts(as, base, size, NULL)) {
168	spinlock_unlock(&as->lock);	168	spinlock_unlock(&as->lock);
169	interrupts_restore(ipl);	169	interrupts_restore(ipl);
170	return NULL;	170	return NULL;
171	}	171	}
172		172
173	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	173	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
174		174
175	spinlock_initialize(&a->lock, "as_area_lock");	175	spinlock_initialize(&a->lock, "as_area_lock");
176		176
177	a->flags = flags;	177	a->flags = flags;
178	a->attributes = attrs;	178	a->attributes = attrs;
179	a->pages = SIZE2FRAMES(size);	179	a->pages = SIZE2FRAMES(size);
180	a->base = base;	180	a->base = base;
181		181
182	btree_insert(&as->as_area_btree, base, (void *) a, NULL);	182	btree_insert(&as->as_area_btree, base, (void *) a, NULL);
183		183
184	spinlock_unlock(&as->lock);	184	spinlock_unlock(&as->lock);
185	interrupts_restore(ipl);	185	interrupts_restore(ipl);
186		186
187	return a;	187	return a;
188	}	188	}
189		189
190	/** Find address space area and change it.	190	/** Find address space area and change it.
191	*	191	*
192	* @param as Address space.	192	* @param as Address space.
193	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	193	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
194	* @param size New size of the virtual memory block starting at address.	194	* @param size New size of the virtual memory block starting at address.
195	* @param flags Flags influencing the remap operation. Currently unused.	195	* @param flags Flags influencing the remap operation. Currently unused.
196	*	196	*
197	* @return Zero on success or a value from @ref errno.h otherwise.	197	* @return Zero on success or a value from @ref errno.h otherwise.
198	*/	198	*/
199	int as_area_resize(as_t *as, __address address, size_t size, int flags)	199	int as_area_resize(as_t *as, __address address, size_t size, int flags)
200	{	200	{
201	as_area_t *area;	201	as_area_t *area;
202	ipl_t ipl;	202	ipl_t ipl;
203	size_t pages;	203	size_t pages;
204		204
205	ipl = interrupts_disable();	205	ipl = interrupts_disable();
206	spinlock_lock(&as->lock);	206	spinlock_lock(&as->lock);
207		207
208	/*	208	/*
209	* Locate the area.	209	* Locate the area.
210	*/	210	*/
211	area = find_area_and_lock(as, address);	211	area = find_area_and_lock(as, address);
212	if (!area) {	212	if (!area) {
213	spinlock_unlock(&as->lock);	213	spinlock_unlock(&as->lock);
214	interrupts_restore(ipl);	214	interrupts_restore(ipl);
215	return ENOENT;	215	return ENOENT;
216	}	216	}
217		217
218	if (area->flags & AS_AREA_DEVICE) {	218	if (area->flags & AS_AREA_DEVICE) {
219	/*	219	/*
220	* Remapping of address space areas associated	220	* Remapping of address space areas associated
221	* with memory mapped devices is not supported.	221	* with memory mapped devices is not supported.
222	*/	222	*/
223	spinlock_unlock(&area->lock);	223	spinlock_unlock(&area->lock);
224	spinlock_unlock(&as->lock);	224	spinlock_unlock(&as->lock);
225	interrupts_restore(ipl);	225	interrupts_restore(ipl);
226	return ENOTSUP;	226	return ENOTSUP;
227	}	227	}
228		228
229	pages = SIZE2FRAMES((address - area->base) + size);	229	pages = SIZE2FRAMES((address - area->base) + size);
230	if (!pages) {	230	if (!pages) {
231	/*	231	/*
232	* Zero size address space areas are not allowed.	232	* Zero size address space areas are not allowed.
233	*/	233	*/
234	spinlock_unlock(&area->lock);	234	spinlock_unlock(&area->lock);
235	spinlock_unlock(&as->lock);	235	spinlock_unlock(&as->lock);
236	interrupts_restore(ipl);	236	interrupts_restore(ipl);
237	return EPERM;	237	return EPERM;
238	}	238	}
239		239
240	if (pages < area->pages) {	240	if (pages < area->pages) {
241	int i;	241	int i;
242		242
243	/*	243	/*
244	* Shrinking the area.	244	* Shrinking the area.
245	* No need to check for overlaps.	245	* No need to check for overlaps.
246	*/	246	*/
247	for (i = pages; i < area->pages; i++) {	247	for (i = pages; i < area->pages; i++) {
248	pte_t *pte;	248	pte_t *pte;
249		249
250	/*	250	/*
251	* Releasing physical memory.	251	* Releasing physical memory.
252	* This depends on the fact that the memory was allocated using frame_alloc().	252	* This depends on the fact that the memory was allocated using frame_alloc().
253	*/	253	*/
254	page_table_lock(as, false);	254	page_table_lock(as, false);
255	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);	255	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
256	if (pte && PTE_VALID(pte)) {	256	if (pte && PTE_VALID(pte)) {
257	__address frame;	257	__address frame;
258		258
259	ASSERT(PTE_PRESENT(pte));	259	ASSERT(PTE_PRESENT(pte));
260	frame = PTE_GET_FRAME(pte);	260	frame = PTE_GET_FRAME(pte);
261	page_mapping_remove(as, area->base + i*PAGE_SIZE);	261	page_mapping_remove(as, area->base + i*PAGE_SIZE);
262	page_table_unlock(as, false);	262	page_table_unlock(as, false);
263		263
264	frame_free(ADDR2PFN(frame));	264	frame_free(ADDR2PFN(frame));
265	} else {	265	} else {
266	page_table_unlock(as, false);	266	page_table_unlock(as, false);
267	}	267	}
268	}	268	}
269	/*	269	/*
270	* Invalidate TLB's.	270	* Invalidate TLB's.
271	*/	271	*/
272	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	272	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
273	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	273	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
274	tlb_shootdown_finalize();	274	tlb_shootdown_finalize();
275	} else {	275	} else {
276	/*	276	/*
277	* Growing the area.	277	* Growing the area.
278	* Check for overlaps with other address space areas.	278	* Check for overlaps with other address space areas.
279	*/	279	*/
280	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {	280	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
281	spinlock_unlock(&area->lock);	281	spinlock_unlock(&area->lock);
282	spinlock_unlock(&as->lock);	282	spinlock_unlock(&as->lock);
283	interrupts_restore(ipl);	283	interrupts_restore(ipl);
284	return EADDRNOTAVAIL;	284	return EADDRNOTAVAIL;
285	}	285	}
286	}	286	}
287		287
288	area->pages = pages;	288	area->pages = pages;
289		289
290	spinlock_unlock(&area->lock);	290	spinlock_unlock(&area->lock);
291	spinlock_unlock(&as->lock);	291	spinlock_unlock(&as->lock);
292	interrupts_restore(ipl);	292	interrupts_restore(ipl);
293		293
294	return 0;	294	return 0;
295	}	295	}
296		296
297	/** Destroy address space area.	297	/** Destroy address space area.
298	*	298	*
299	* @param as Address space.	299	* @param as Address space.
300	* @param address Address withing the area to be deleted.	300	* @param address Address withing the area to be deleted.
301	*	301	*
302	* @return Zero on success or a value from @ref errno.h on failure.	302	* @return Zero on success or a value from @ref errno.h on failure.
303	*/	303	*/
304	int as_area_destroy(as_t *as, __address address)	304	int as_area_destroy(as_t *as, __address address)
305	{	305	{
306	as_area_t *area;	306	as_area_t *area;
307	__address base;	307	__address base;
308	ipl_t ipl;	308	ipl_t ipl;
309	int i;	309	int i;
310		310
311	ipl = interrupts_disable();	311	ipl = interrupts_disable();
312	spinlock_lock(&as->lock);	312	spinlock_lock(&as->lock);
313		313
314	area = find_area_and_lock(as, address);	314	area = find_area_and_lock(as, address);
315	if (!area) {	315	if (!area) {
316	spinlock_unlock(&as->lock);	316	spinlock_unlock(&as->lock);
317	interrupts_restore(ipl);	317	interrupts_restore(ipl);
318	return ENOENT;	318	return ENOENT;
319	}	319	}
320		320
321	base = area->base;	321	base = area->base;
322	for (i = 0; i < area->pages; i++) {	322	for (i = 0; i < area->pages; i++) {
323	pte_t *pte;	323	pte_t *pte;
324		324
325	/*	325	/*
326	* Releasing physical memory.	326	* Releasing physical memory.
327	* Areas mapping memory-mapped devices are treated differently than	327	* Areas mapping memory-mapped devices are treated differently than
328	* areas backing frame_alloc()'ed memory.	328	* areas backing frame_alloc()'ed memory.
329	*/	329	*/
330	page_table_lock(as, false);	330	page_table_lock(as, false);
331	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);	331	pte = page_mapping_find(as, area->base + i*PAGE_SIZE);
332	if (pte && PTE_VALID(pte)) {	332	if (pte && PTE_VALID(pte)) {
333	ASSERT(PTE_PRESENT(pte));	333	ASSERT(PTE_PRESENT(pte));
334	page_mapping_remove(as, area->base + i*PAGE_SIZE);	334	page_mapping_remove(as, area->base + i*PAGE_SIZE);
335	if (area->flags & AS_AREA_DEVICE) {	335	if (area->flags & AS_AREA_DEVICE) {
336	__address frame;	336	__address frame;
337	frame = PTE_GET_FRAME(pte);	337	frame = PTE_GET_FRAME(pte);
338	frame_free(ADDR2PFN(frame));	338	frame_free(ADDR2PFN(frame));
339	}	339	}
340	page_table_unlock(as, false);	340	page_table_unlock(as, false);
341	} else {	341	} else {
342	page_table_unlock(as, false);	342	page_table_unlock(as, false);
343	}	343	}
344	}	344	}
345	/*	345	/*
346	* Invalidate TLB's.	346	* Invalidate TLB's.
347	*/	347	*/
348	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);	348	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);
349	tlb_invalidate_pages(AS->asid, area->base, area->pages);	349	tlb_invalidate_pages(AS->asid, area->base, area->pages);
350	tlb_shootdown_finalize();	350	tlb_shootdown_finalize();
351		351
352	area->attributes \|= AS_AREA_ATTR_PARTIAL;	352	area->attributes \|= AS_AREA_ATTR_PARTIAL;
353	spinlock_unlock(&area->lock);	353	spinlock_unlock(&area->lock);
354		354
355	/*	355	/*
356	* Remove the empty area from address space.	356	* Remove the empty area from address space.
357	*/	357	*/
358	btree_remove(&AS->as_area_btree, base, NULL);	358	btree_remove(&AS->as_area_btree, base, NULL);
359		359
360	free(area);	360	free(area);
361		361
362	spinlock_unlock(&AS->lock);	362	spinlock_unlock(&AS->lock);
363	interrupts_restore(ipl);	363	interrupts_restore(ipl);
364	return 0;	364	return 0;
365	}	365	}
366		366
367	/** Steal address space area from another task.	367	/** Steal address space area from another task.
368	*	368	*
369	* Address space area is stolen from another task	369	* Address space area is stolen from another task
370	* Moreover, any existing mapping	370	* Moreover, any existing mapping
371	* is copied as well, providing thus a mechanism	371	* is copied as well, providing thus a mechanism
372	* for sharing group of pages. The source address	372	* for sharing group of pages. The source address
373	* space area and any associated mapping is preserved.	373	* space area and any associated mapping is preserved.
374	*	374	*
375	* @param src_task Pointer of source task	375	* @param src_task Pointer of source task
376	* @param src_base Base address of the source address space area.	376	* @param src_base Base address of the source address space area.
377	* @param acc_size Expected size of the source area	377	* @param acc_size Expected size of the source area
378	* @param dst_base Target base address	378	* @param dst_base Target base address
379	*	379	*
380	* @return Zero on success or ENOENT if there is no such task or	380	* @return Zero on success or ENOENT if there is no such task or
381	* if there is no such address space area,	381	* if there is no such address space area,
382	* EPERM if there was a problem in accepting the area or	382	* EPERM if there was a problem in accepting the area or
383	* ENOMEM if there was a problem in allocating destination	383	* ENOMEM if there was a problem in allocating destination
384	* address space area.	384	* address space area.
385	*/	385	*/
386	int as_area_steal(task_t *src_task, __address src_base, size_t acc_size,	386	int as_area_steal(task_t *src_task, __address src_base, size_t acc_size,
387	__address dst_base)	387	__address dst_base)
388	{	388	{
389	ipl_t ipl;	389	ipl_t ipl;
390	count_t i;	390	count_t i;
391	as_t *src_as;	391	as_t *src_as;
392	int src_flags;	392	int src_flags;
393	size_t src_size;	393	size_t src_size;
394	as_area_t src_area, dst_area;	394	as_area_t src_area, dst_area;
395		395
396	ipl = interrupts_disable();	396	ipl = interrupts_disable();
397	spinlock_lock(&src_task->lock);	397	spinlock_lock(&src_task->lock);
398	src_as = src_task->as;	398	src_as = src_task->as;
399		399
400	spinlock_lock(&src_as->lock);	400	spinlock_lock(&src_as->lock);
401	src_area = find_area_and_lock(src_as, src_base);	401	src_area = find_area_and_lock(src_as, src_base);
402	if (!src_area) {	402	if (!src_area) {
403	/*	403	/*
404	* Could not find the source address space area.	404	* Could not find the source address space area.
405	*/	405	*/
406	spinlock_unlock(&src_task->lock);	406	spinlock_unlock(&src_task->lock);
407	spinlock_unlock(&src_as->lock);	407	spinlock_unlock(&src_as->lock);
408	interrupts_restore(ipl);	408	interrupts_restore(ipl);
409	return ENOENT;	409	return ENOENT;
410	}	410	}
411	src_size = src_area->pages * PAGE_SIZE;	411	src_size = src_area->pages * PAGE_SIZE;
412	src_flags = src_area->flags;	412	src_flags = src_area->flags;
413	spinlock_unlock(&src_area->lock);	413	spinlock_unlock(&src_area->lock);
414	spinlock_unlock(&src_as->lock);	414	spinlock_unlock(&src_as->lock);
415		415
416		416
417	if (src_size != acc_size) {	417	if (src_size != acc_size) {
418	spinlock_unlock(&src_task->lock);	418	spinlock_unlock(&src_task->lock);
419	interrupts_restore(ipl);	419	interrupts_restore(ipl);
420	return EPERM;	420	return EPERM;
421	}	421	}
422	/*	422	/*
423	* Create copy of the source address space area.	423	* Create copy of the source address space area.
424	* The destination area is created with AS_AREA_ATTR_PARTIAL	424	* The destination area is created with AS_AREA_ATTR_PARTIAL
425	* attribute set which prevents race condition with	425	* attribute set which prevents race condition with
426	* preliminary as_page_fault() calls.	426	* preliminary as_page_fault() calls.
427	*/	427	*/
428	dst_area = as_area_create(AS, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL);	428	dst_area = as_area_create(AS, src_flags, src_size, dst_base, AS_AREA_ATTR_PARTIAL);
429	if (!dst_area) {	429	if (!dst_area) {
430	/*	430	/*
431	* Destination address space area could not be created.	431	* Destination address space area could not be created.
432	*/	432	*/
433	spinlock_unlock(&src_task->lock);	433	spinlock_unlock(&src_task->lock);
434	interrupts_restore(ipl);	434	interrupts_restore(ipl);
435	return ENOMEM;	435	return ENOMEM;
436	}	436	}
437		437
438	spinlock_unlock(&src_task->lock);	438	spinlock_unlock(&src_task->lock);
439		439
440	/*	440	/*
441	* Avoid deadlock by first locking the address space with lower address.	441	* Avoid deadlock by first locking the address space with lower address.
442	*/	442	*/
443	if (AS < src_as) {	443	if (AS < src_as) {
444	spinlock_lock(&AS->lock);	444	spinlock_lock(&AS->lock);
445	spinlock_lock(&src_as->lock);	445	spinlock_lock(&src_as->lock);
446	} else {	446	} else {
447	spinlock_lock(&AS->lock);	447	spinlock_lock(&AS->lock);
448	spinlock_lock(&src_as->lock);	448	spinlock_lock(&src_as->lock);
449	}	449	}
450		450
451	for (i = 0; i < SIZE2FRAMES(src_size); i++) {	451	for (i = 0; i < SIZE2FRAMES(src_size); i++) {
452	pte_t *pte;	452	pte_t *pte;
453	__address frame;	453	__address frame;
454		454
455	page_table_lock(src_as, false);	455	page_table_lock(src_as, false);
456	pte = page_mapping_find(src_as, src_base + i*PAGE_SIZE);	456	pte = page_mapping_find(src_as, src_base + i*PAGE_SIZE);
457	if (pte && PTE_VALID(pte)) {	457	if (pte && PTE_VALID(pte)) {
458	ASSERT(PTE_PRESENT(pte));	458	ASSERT(PTE_PRESENT(pte));
459	frame = PTE_GET_FRAME(pte);	459	frame = PTE_GET_FRAME(pte);
460	if (!(src_flags & AS_AREA_DEVICE))	460	if (!(src_flags & AS_AREA_DEVICE))
461	frame_reference_add(ADDR2PFN(frame));	461	frame_reference_add(ADDR2PFN(frame));
462	page_table_unlock(src_as, false);	462	page_table_unlock(src_as, false);
463	} else {	463	} else {
464	page_table_unlock(src_as, false);	464	page_table_unlock(src_as, false);
465	continue;	465	continue;
466	}	466	}
467		467
468	page_table_lock(AS, false);	468	page_table_lock(AS, false);
469	page_mapping_insert(AS, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags));	469	page_mapping_insert(AS, dst_base + i*PAGE_SIZE, frame, area_flags_to_page_flags(src_flags));
470	page_table_unlock(AS, false);	470	page_table_unlock(AS, false);
471	}	471	}
472		472
473	/*	473	/*
474	* Now the destination address space area has been	474	* Now the destination address space area has been
475	* fully initialized. Clear the AS_AREA_ATTR_PARTIAL	475	* fully initialized. Clear the AS_AREA_ATTR_PARTIAL
476	* attribute.	476	* attribute.
477	*/	477	*/
478	spinlock_lock(&dst_area->lock);	478	spinlock_lock(&dst_area->lock);
479	dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;	479	dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
480	spinlock_unlock(&dst_area->lock);	480	spinlock_unlock(&dst_area->lock);
481		481
482	spinlock_unlock(&AS->lock);	482	spinlock_unlock(&AS->lock);
483	spinlock_unlock(&src_as->lock);	483	spinlock_unlock(&src_as->lock);
484	interrupts_restore(ipl);	484	interrupts_restore(ipl);
485		485
486	return 0;	486	return 0;
487	}	487	}
488		488
489	/** Initialize mapping for one page of address space.	489	/** Initialize mapping for one page of address space.
490	*	490	*
491	* This functions maps 'page' to 'frame' according	491	* This functions maps 'page' to 'frame' according
492	* to attributes of the address space area to	492	* to attributes of the address space area to
493	* wich 'page' belongs.	493	* wich 'page' belongs.
494	*	494	*
495	* @param as Target address space.	495	* @param as Target address space.
496	* @param page Virtual page within the area.	496	* @param page Virtual page within the area.
497	* @param frame Physical frame to which page will be mapped.	497	* @param frame Physical frame to which page will be mapped.
498	*/	498	*/
499	void as_set_mapping(as_t *as, __address page, __address frame)	499	void as_set_mapping(as_t *as, __address page, __address frame)
500	{	500	{

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(root)/tags/0.1.1/kernel/generic/src/mm/as.c – Rev 1963 → 1968