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.
 */
 
/**
 * @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 <synch/mutex.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 <align.h>
#include <arch/types.h>
#include <typedefs.h>
#include <syscall/copy.h>
#include <arch/interrupt.h>
 
/** This structure contains information associated with the shared address space area. */
struct share_info {
    mutex_t lock;       /**< This lock must be acquired only when the as_area lock is held. */
    count_t refcount;   /**< This structure can be deallocated if refcount drops to 0. */
    btree_t pagemap;    /**< B+tree containing complete map of anonymous pages of the shared area. */
};
 
as_operations_t *as_operations = NULL;
 
/** Address space lock. It protects inactive_as_with_asid_head. Must be acquired before as_t mutex. */
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 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);
 
static void sh_info_remove_reference(share_info_t *sh_info);
 
/** 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);
    mutex_initialize(&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.
 * @param backend Address space area backend. NULL if no backend is used.
 * @param backend_data NULL or a pointer to an array holding two void *.
 *
 * @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,
           mem_backend_t *backend, void **backend_data)
{
    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();
    mutex_lock(&as->lock);
   
    if (!check_area_conflicts(as, base, size, NULL)) {
        mutex_unlock(&as->lock);
        interrupts_restore(ipl);
        return NULL;
    }
   
    a = (as_area_t *) malloc(sizeof(as_area_t), 0);
 
    mutex_initialize(&a->lock);
   
    a->flags = flags;
    a->attributes = attrs;
    a->pages = SIZE2FRAMES(size);
    a->base = base;
    a->sh_info = NULL;
    a->backend = backend;
    if (backend_data) {
        a->backend_data[0] = backend_data[0];
        a->backend_data[1] = backend_data[1];
    }
    btree_create(&a->used_space);
   
    btree_insert(&as->as_area_btree, base, (void *) a, NULL);
 
    mutex_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();
    mutex_lock(&as->lock);
   
    /*
     * Locate the area.
     */
    area = find_area_and_lock(as, address);
    if (!area) {
        mutex_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.
         */
        mutex_unlock(&area->lock);
        mutex_unlock(&as->lock);
        interrupts_restore(ipl);
        return ENOTSUP;
    }
    if (area->sh_info) {
        /*
         * Remapping of shared address space areas
         * is not supported.
         */
        mutex_unlock(&area->lock);
        mutex_unlock(&as->lock);
        interrupts_restore(ipl);
        return ENOTSUP;
    }
 
    pages = SIZE2FRAMES((address - area->base) + size);
    if (!pages) {
        /*
         * Zero size address space areas are not allowed.
         */
        mutex_unlock(&area->lock);
        mutex_unlock(&as->lock);
        interrupts_restore(ipl);
        return EPERM;
    }
   
    if (pages < area->pages) {
        bool cond;
        __address start_free = area->base + pages*PAGE_SIZE;
 
        /*
         * Shrinking the area.
         * No need to check for overlaps.
         */
 
        /*
         * Remove frames belonging to used space starting from
         * the highest addresses downwards until an overlap with
         * the resized address space area is found. Note that this
         * is also the right way to remove part of the used_space
         * B+tree leaf list.
         */    
        for (cond = true; cond;) {
            btree_node_t *node;
       
            ASSERT(!list_empty(&area->used_space.leaf_head));
            node = list_get_instance(area->used_space.leaf_head.prev, btree_node_t, leaf_link);
            if ((cond = (bool) node->keys)) {
                __address b = node->key[node->keys - 1];
                count_t c = (count_t) node->value[node->keys - 1];
                int i = 0;
           
                if (overlaps(b, c*PAGE_SIZE, area->base, pages*PAGE_SIZE)) {
                   
                    if (b + c*PAGE_SIZE <= start_free) {
                        /*
                         * The whole interval fits completely
                         * in the resized address space area.
                         */
                        break;
                    }
       
                    /*
                     * Part of the interval corresponding to b and c
                     * overlaps with the resized address space area.
                     */
       
                    cond = false;   /* we are almost done */
                    i = (start_free - b) >> PAGE_WIDTH;
                    if (!used_space_remove(area, start_free, c - i))
                        panic("Could not remove used space.");
                } else {
                    /*
                     * The interval of used space can be completely removed.
                     */
                    if (!used_space_remove(area, b, c))
                        panic("Could not remove used space.\n");
                }
           
                for (; i < c; i++) {
                    pte_t *pte;
           
                    page_table_lock(as, false);
                    pte = page_mapping_find(as, b + i*PAGE_SIZE);
                    ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
                    if (area->backend && area->backend->backend_frame_free) {
                        area->backend->backend_frame_free(area,
                            b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
                    }
                    page_mapping_remove(as, b + i*PAGE_SIZE);
                    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)) {
            mutex_unlock(&area->lock);
            mutex_unlock(&as->lock);       
            interrupts_restore(ipl);
            return EADDRNOTAVAIL;
        }
    }
 
    area->pages = pages;
   
    mutex_unlock(&area->lock);
    mutex_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;
 
    ipl = interrupts_disable();
    mutex_lock(&as->lock);
 
    area = find_area_and_lock(as, address);
    if (!area) {
        mutex_unlock(&as->lock);
        interrupts_restore(ipl);
        return ENOENT;
    }
 
    base = area->base;
    if (!(area->flags & AS_AREA_DEVICE)) {
        bool cond; 
   
        /*
         * Releasing physical memory.
         * Areas mapping memory-mapped devices are treated differently than
         * areas backing frame_alloc()'ed memory.
         */
 
        /*
         * Visit only the pages mapped by used_space B+tree.
         * Note that we must be very careful when walking the tree
         * leaf list and removing used space as the leaf list changes
         * unpredictibly after each remove. The solution is to actually
         * not walk the tree at all, but to remove items from the head
         * of the leaf list until there are some keys left.
         */
        for (cond = true; cond;) {
            btree_node_t *node;
       
            ASSERT(!list_empty(&area->used_space.leaf_head));
            node = list_get_instance(area->used_space.leaf_head.next, btree_node_t, leaf_link);
            if ((cond = (bool) node->keys)) {
                __address b = node->key[0];
                count_t i;
                pte_t *pte;
           
                for (i = 0; i < (count_t) node->value[0]; i++) {
                    page_table_lock(as, false);
                    pte = page_mapping_find(as, b + i*PAGE_SIZE);
                    ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
                    if (area->backend && area->backend->backend_frame_free) {
                        area->backend->backend_frame_free(area,
                            b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
                    }
                    page_mapping_remove(as, b + i*PAGE_SIZE);
                    page_table_unlock(as, false);
                }
                if (!used_space_remove(area, b, i))
                    panic("Could not remove used space.\n");
            }
        }
    }
    btree_destroy(&area->used_space);
 
    /*
     * 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;
   
    if (area->sh_info)
        sh_info_remove_reference(area->sh_info);
       
    mutex_unlock(&area->lock);
 
    /*
     * Remove the empty area from address space.
     */
    btree_remove(&AS->as_area_btree, base, NULL);
   
    free(area);
   
    mutex_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;
   
    mutex_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);
        mutex_unlock(&src_as->lock);
        interrupts_restore(ipl);
        return ENOENT;
    }
    src_size = src_area->pages * PAGE_SIZE;
    src_flags = src_area->flags;
    mutex_unlock(&src_area->lock);
    mutex_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, &anon_backend, NULL);
    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) {
        mutex_lock(&AS->lock);
        mutex_lock(&src_as->lock);
    } else {
        mutex_lock(&AS->lock);
        mutex_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.
     */
    mutex_lock(&dst_area->lock);
    dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
    mutex_unlock(&dst_area->lock);
   
    mutex_unlock(&AS->lock);
    mutex_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");
    }
 
    ASSERT(!area->backend);
   
    page_mapping_insert(as, page, frame, as_area_get_flags(area));
    if (!used_space_insert(area, page, 1))
        panic("Could not insert used space.\n");
   
    mutex_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. It decides
 * whether the page fault can be resolved by any backend
 * and if so, it invokes the backend to resolve the page
 * fault.
 *
 * Interrupts are assumed disabled.
 *
 * @param page Faulting page.
 * @param istate Pointer to interrupted state.
 *
 * @return AS_PF_FAULT on page fault, AS_PF_OK on success or AS_PF_DEFER 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;
 
   
    if (!THREAD)
        return AS_PF_FAULT;
       
    ASSERT(AS);
 
    mutex_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.
         */
        mutex_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.
         */
        mutex_unlock(&area->lock);
        mutex_unlock(&AS->lock);
        goto page_fault;       
    }
 
    if (!area->backend || !area->backend->backend_page_fault) {
        /*
         * The address space area is not backed by any backend
         * or the backend cannot handle page faults.
         */
        mutex_unlock(&area->lock);
        mutex_unlock(&AS->lock);
        goto page_fault;       
    }
 
    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);
            mutex_unlock(&area->lock);
            mutex_unlock(&AS->lock);
            return AS_PF_OK;
        }
    }
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   
    /*
 
 
     * Resort to the backend page fault handler.
     */
    if (area->backend->backend_page_fault(area, page) != AS_PF_OK) {
        page_table_unlock(AS, false);
        mutex_unlock(&area->lock);
        mutex_unlock(&AS->lock);
        goto page_fault;
    }
   
    page_table_unlock(AS, false);
    mutex_unlock(&area->lock);
    mutex_unlock(&AS->lock);
    return AS_PF_OK;
 
page_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.
 *
 * Note that this function cannot sleep as it is essentially a part of
 * the scheduling. Sleeping here would lead to deadlock on wakeup.
 *
 * @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) {
        mutex_lock_active(&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);
        }
        mutex_unlock(&old->lock);
    }
 
    /*
     * Second, prepare the new address space.
     */
    mutex_lock_active(&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);
    mutex_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();
        mutex_lock_active(&new->lock);
        new->asid = asid;
        mutex_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 as_area_get_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 */
        mutex_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];
        mutex_lock(&a->lock);
        if ((a->base <= va) && (va < a->base + a->pages * PAGE_SIZE)) {
            return a;
        }
        mutex_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];
        mutex_lock(&a->lock);
        if (va < a->base + a->pages * PAGE_SIZE) {
            return a;
        }
        mutex_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];
        mutex_lock(&a->lock);
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
            mutex_unlock(&a->lock);
            return false;
        }
        mutex_unlock(&a->lock);
    }
    if ((node = btree_leaf_node_right_neighbour(&as->as_area_btree, leaf))) {
        a = (as_area_t *) node->value[0];
        mutex_lock(&a->lock);
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
            mutex_unlock(&a->lock);
            return false;
        }
        mutex_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;
   
        mutex_lock(&a->lock);
        if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) {
            mutex_unlock(&a->lock);
            return false;
        }
        mutex_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 the address space area with given 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;
        mutex_unlock(&src_area->lock);
    } else {
        size = 0;
    }
    interrupts_restore(ipl);
    return size;
}
 
/** Mark portion of address space area as used.
 *
 * The address space area must be already locked.
 *
 * @param a Address space area.
 * @param page First page to be marked.
 * @param count Number of page to be marked.
 *
 * @return 0 on failure and 1 on success.
 */
int used_space_insert(as_area_t *a, __address page, count_t count)
{
    btree_node_t *leaf, *node;
    count_t pages;
    int i;
 
    ASSERT(page == ALIGN_DOWN(page, PAGE_SIZE));
    ASSERT(count);
 
    pages = (count_t) btree_search(&a->used_space, page, &leaf);
    if (pages) {
        /*
         * We hit the beginning of some used space.
         */
        return 0;
    }
 
    node = btree_leaf_node_left_neighbour(&a->used_space, leaf);
    if (node) {
        __address left_pg = node->key[node->keys - 1], right_pg = leaf->key[0];
        count_t left_cnt = (count_t) node->value[node->keys - 1], right_cnt = (count_t) leaf->value[0];
       
        /*
         * Examine the possibility that the interval fits
         * somewhere between the rightmost interval of
         * the left neigbour and the first interval of the leaf.
         */
         
        if (page >= right_pg) {
            /* Do nothing. */
        } else if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
            /* The interval intersects with the left interval. */
            return 0;
        } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
            /* The interval intersects with the right interval. */
            return 0;          
        } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
            /* The interval can be added by merging the two already present intervals. */
            node->value[node->keys - 1] += count + right_cnt;
            btree_remove(&a->used_space, right_pg, leaf);
            return 1;
        } else if (page == left_pg + left_cnt*PAGE_SIZE) {
            /* The interval can be added by simply growing the left interval. */
            node->value[node->keys - 1] += count;
            return 1;
        } else if (page + count*PAGE_SIZE == right_pg) {
            /*
             * The interval can be addded by simply moving base of the right
             * interval down and increasing its size accordingly.
             */
            leaf->value[0] += count;
            leaf->key[0] = page;
            return 1;
        } else {
            /*
             * The interval is between both neigbouring intervals,
             * but cannot be merged with any of them.
             */
            btree_insert(&a->used_space, page, (void *) count, leaf);
            return 1;
        }
    } else if (page < leaf->key[0]) {
        __address right_pg = leaf->key[0];
        count_t right_cnt = (count_t) leaf->value[0];
   
        /*
         * Investigate the border case in which the left neighbour does not
         * exist but the interval fits from the left.
         */
         
        if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
            /* The interval intersects with the right interval. */
            return 0;
        } else if (page + count*PAGE_SIZE == right_pg) {
            /*
             * The interval can be added by moving the base of the right interval down
             * and increasing its size accordingly.
             */
            leaf->key[0] = page;
            leaf->value[0] += count;
            return 1;
        } else {
            /*
             * The interval doesn't adjoin with the right interval.
             * It must be added individually.
             */
            btree_insert(&a->used_space, page, (void *) count, leaf);
            return 1;
        }
    }
 
    node = btree_leaf_node_right_neighbour(&a->used_space, leaf);
    if (node) {
        __address left_pg = leaf->key[leaf->keys - 1], right_pg = node->key[0];
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1], right_cnt = (count_t) node->value[0];
       
        /*
         * Examine the possibility that the interval fits
         * somewhere between the leftmost interval of
         * the right neigbour and the last interval of the leaf.
         */
 
        if (page < left_pg) {
            /* Do nothing. */
        } else if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
            /* The interval intersects with the left interval. */
            return 0;
        } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
            /* The interval intersects with the right interval. */
            return 0;          
        } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
            /* The interval can be added by merging the two already present intervals. */
            leaf->value[leaf->keys - 1] += count + right_cnt;
            btree_remove(&a->used_space, right_pg, node);
            return 1;
        } else if (page == left_pg + left_cnt*PAGE_SIZE) {
            /* The interval can be added by simply growing the left interval. */
            leaf->value[leaf->keys - 1] +=  count;
            return 1;
        } else if (page + count*PAGE_SIZE == right_pg) {
            /*
             * The interval can be addded by simply moving base of the right
             * interval down and increasing its size accordingly.
             */
            node->value[0] += count;
            node->key[0] = page;
            return 1;
        } else {
            /*
             * The interval is between both neigbouring intervals,
             * but cannot be merged with any of them.
             */
            btree_insert(&a->used_space, page, (void *) count, leaf);
            return 1;
        }
    } else if (page >= leaf->key[leaf->keys - 1]) {
        __address left_pg = leaf->key[leaf->keys - 1];
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1];
   
        /*
         * Investigate the border case in which the right neighbour does not
         * exist but the interval fits from the right.
         */
         
        if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
            /* The interval intersects with the left interval. */
            return 0;
        } else if (left_pg + left_cnt*PAGE_SIZE == page) {
            /* The interval can be added by growing the left interval. */
            leaf->value[leaf->keys - 1] += count;
            return 1;
        } else {
            /*
             * The interval doesn't adjoin with the left interval.
             * It must be added individually.
             */
            btree_insert(&a->used_space, page, (void *) count, leaf);
            return 1;
        }
    }
   
    /*
     * Note that if the algorithm made it thus far, the interval can fit only
     * between two other intervals of the leaf. The two border cases were already
     * resolved.
     */
    for (i = 1; i < leaf->keys; i++) {
        if (page < leaf->key[i]) {
            __address left_pg = leaf->key[i - 1], right_pg = leaf->key[i];
            count_t left_cnt = (count_t) leaf->value[i - 1], right_cnt = (count_t) leaf->value[i];
 
            /*
             * The interval fits between left_pg and right_pg.
             */
 
            if (overlaps(page, count*PAGE_SIZE, left_pg, left_cnt*PAGE_SIZE)) {
                /* The interval intersects with the left interval. */
                return 0;
            } else if (overlaps(page, count*PAGE_SIZE, right_pg, right_cnt*PAGE_SIZE)) {
                /* The interval intersects with the right interval. */
                return 0;          
            } else if ((page == left_pg + left_cnt*PAGE_SIZE) && (page + count*PAGE_SIZE == right_pg)) {
                /* The interval can be added by merging the two already present intervals. */
                leaf->value[i - 1] += count + right_cnt;
                btree_remove(&a->used_space, right_pg, leaf);
                return 1;
            } else if (page == left_pg + left_cnt*PAGE_SIZE) {
                /* The interval can be added by simply growing the left interval. */
                leaf->value[i - 1] += count;
                return 1;
            } else if (page + count*PAGE_SIZE == right_pg) {
                /*
                     * The interval can be addded by simply moving base of the right
                 * interval down and increasing its size accordingly.
                 */
                leaf->value[i] += count;
                leaf->key[i] = page;
                return 1;
            } else {
                /*
                 * The interval is between both neigbouring intervals,
                 * but cannot be merged with any of them.
                 */
                btree_insert(&a->used_space, page, (void *) count, leaf);
                return 1;
            }
        }
    }
 
    panic("Inconsistency detected while adding %d pages of used space at %P.\n", count, page);
}
 
/** Mark portion of address space area as unused.
 *
 * The address space area must be already locked.
 *
 * @param a Address space area.
 * @param page First page to be marked.
 * @param count Number of page to be marked.
 *
 * @return 0 on failure and 1 on success.
 */
int used_space_remove(as_area_t *a, __address page, count_t count)
{
    btree_node_t *leaf, *node;
    count_t pages;
    int i;
 
    ASSERT(page == ALIGN_DOWN(page, PAGE_SIZE));
    ASSERT(count);
 
    pages = (count_t) btree_search(&a->used_space, page, &leaf);
    if (pages) {
        /*
         * We are lucky, page is the beginning of some interval.
         */
        if (count > pages) {
            return 0;
        } else if (count == pages) {
            btree_remove(&a->used_space, page, leaf);
            return 1;
        } else {
            /*
             * Find the respective interval.
             * Decrease its size and relocate its start address.
             */
            for (i = 0; i < leaf->keys; i++) {
                if (leaf->key[i] == page) {
                    leaf->key[i] += count*PAGE_SIZE;
                    leaf->value[i] -= count;
                    return 1;
                }
            }
            goto error;
        }
    }
 
    node = btree_leaf_node_left_neighbour(&a->used_space, leaf);
    if (node && page < leaf->key[0]) {
        __address left_pg = node->key[node->keys - 1];
        count_t left_cnt = (count_t) node->value[node->keys - 1];
 
        if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
            if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
                /*
                 * The interval is contained in the rightmost interval
                 * of the left neighbour and can be removed by
                 * updating the size of the bigger interval.
                 */
                node->value[node->keys - 1] -= count;
                return 1;
            } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
                count_t new_cnt;
               
                /*
                 * The interval is contained in the rightmost interval
                 * of the left neighbour but its removal requires
                 * both updating the size of the original interval and
                 * also inserting a new interval.
                 */
                new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
                node->value[node->keys - 1] -= count + new_cnt;
                btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
                return 1;
            }
        }
        return 0;
    } else if (page < leaf->key[0]) {
        return 0;
    }
   
    if (page > leaf->key[leaf->keys - 1]) {
        __address left_pg = leaf->key[leaf->keys - 1];
        count_t left_cnt = (count_t) leaf->value[leaf->keys - 1];
 
        if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
            if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
                /*
                 * The interval is contained in the rightmost interval
                 * of the leaf and can be removed by updating the size
                 * of the bigger interval.
                 */
                leaf->value[leaf->keys - 1] -= count;
                return 1;
            } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
                count_t new_cnt;
               
                /*
                 * The interval is contained in the rightmost interval
                 * of the leaf but its removal requires both updating
                 * the size of the original interval and
                 * also inserting a new interval.
                 */
                new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
                leaf->value[leaf->keys - 1] -= count + new_cnt;
                btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
                return 1;
            }
        }
        return 0;
    }  
   
    /*
     * The border cases have been already resolved.
     * Now the interval can be only between intervals of the leaf.
     */
    for (i = 1; i < leaf->keys - 1; i++) {
        if (page < leaf->key[i]) {
            __address left_pg = leaf->key[i - 1];
            count_t left_cnt = (count_t) leaf->value[i - 1];
 
            /*
             * Now the interval is between intervals corresponding to (i - 1) and i.
             */
            if (overlaps(left_pg, left_cnt*PAGE_SIZE, page, count*PAGE_SIZE)) {
                if (page + count*PAGE_SIZE == left_pg + left_cnt*PAGE_SIZE) {
                    /*
                    * The interval is contained in the interval (i - 1)
                     * of the leaf and can be removed by updating the size
                     * of the bigger interval.
                     */
                    leaf->value[i - 1] -= count;
                    return 1;
                } else if (page + count*PAGE_SIZE < left_pg + left_cnt*PAGE_SIZE) {
                    count_t new_cnt;
               
                    /*
                     * The interval is contained in the interval (i - 1)
                     * of the leaf but its removal requires both updating
                     * the size of the original interval and
                     * also inserting a new interval.
                     */
                    new_cnt = ((left_pg + left_cnt*PAGE_SIZE) - (page + count*PAGE_SIZE)) >> PAGE_WIDTH;
                    leaf->value[i - 1] -= count + new_cnt;
                    btree_insert(&a->used_space, page + count*PAGE_SIZE, (void *) new_cnt, leaf);
                    return 1;
                }
            }
            return 0;
        }
    }
 
error:
    panic("Inconsistency detected while removing %d pages of used space from %P.\n", count, page);
}
 
/** Remove reference to address space area share info.
 *
 * If the reference count drops to 0, the sh_info is deallocated.
 *
 * @param sh_info Pointer to address space area share info.
 */
void sh_info_remove_reference(share_info_t *sh_info)
{
    bool dealloc = false;
 
    mutex_lock(&sh_info->lock);
    ASSERT(sh_info->refcount);
    if (--sh_info->refcount == 0) {
        dealloc = true;
        bool cond;
       
        /*
         * Now walk carefully the pagemap B+tree and free/remove
         * reference from all frames found there.
         */
        for (cond = true; cond;) {
            btree_node_t *node;
           
            ASSERT(!list_empty(&sh_info->pagemap.leaf_head));
            node = list_get_instance(sh_info->pagemap.leaf_head.next, btree_node_t, leaf_link);
            if ((cond = node->keys)) {
                frame_free(ADDR2PFN((__address) node->value[0]));
                btree_remove(&sh_info->pagemap, node->key[0], node);
            }
        }
       
    }
    mutex_unlock(&sh_info->lock);
   
    if (dealloc) {
        btree_destroy(&sh_info->pagemap);
        free(sh_info);
    }
}
 
static int anon_page_fault(as_area_t *area, __address addr);
static void anon_frame_free(as_area_t *area, __address page, __address frame);
 
/*
 * Anonymous memory backend.
 */
mem_backend_t anon_backend = {
    .backend_page_fault = anon_page_fault,
    .backend_frame_free = anon_frame_free
};
 
/** Service a page fault in the anonymous memory address space area.
 *
 * The address space area and page tables must be already locked.
 *
 * @param area Pointer to the address space area.
 * @param addr Faulting virtual address.
 *
 * @return AS_PF_FAULT on failure (i.e. page fault) or AS_PF_OK on success (i.e. serviced).
 */
int anon_page_fault(as_area_t *area, __address addr)
{
    __address frame;
 
    if (area->sh_info) {
        btree_node_t *leaf;
       
        /*
         * The area is shared, chances are that the mapping can be found
         * in the pagemap of the address space area share info structure.
         * In the case that the pagemap does not contain the respective
         * mapping, a new frame is allocated and the mapping is created.
         */
        mutex_lock(&area->sh_info->lock);
        frame = (__address) btree_search(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE), &leaf);
        if (!frame) {
            bool allocate = true;
            int i;
           
            /*
             * Zero can be returned as a valid frame address.
             * Just a small workaround.
             */
            for (i = 0; i < leaf->keys; i++) {
                if (leaf->key[i] == ALIGN_DOWN(addr, PAGE_SIZE)) {
                    allocate = false;
                    break;
                }
            }
            if (allocate) {
                frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0));
                memsetb(PA2KA(frame), FRAME_SIZE, 0);
               
                /*
                 * Insert the address of the newly allocated frame to the pagemap.
                 */
                btree_insert(&area->sh_info->pagemap, ALIGN_DOWN(addr, PAGE_SIZE), (void *) frame, leaf);
            }
        }
        mutex_unlock(&area->sh_info->lock);
    } else {
 
        /*
         * In general, there can be several reasons that
         * can have caused this fault.
         *
         * - non-existent mapping: the area is an anonymous
         *   area (e.g. heap or 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, addr, frame, as_area_get_flags(area));
    if (!used_space_insert(area, ALIGN_DOWN(addr, PAGE_SIZE), 1))
        panic("Could not insert used space.\n");
       
    return AS_PF_OK;
}
 
/** Free a frame that is backed by the anonymous memory backend.
 *
 * The address space area and page tables must be already locked.
 *
 * @param area Ignored.
 * @param page Ignored.
 * @param frame Frame to be released.
 */
void anon_frame_free(as_area_t *area, __address page, __address frame)
{
    frame_free(ADDR2PFN(frame));
}
 
/*
 * 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, &anon_backend, NULL))
        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 1403	Rev 1409
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 <synch/mutex.h>	57	#include <synch/mutex.h>
58	#include <adt/list.h>	58	#include <adt/list.h>
59	#include <adt/btree.h>	59	#include <adt/btree.h>
60	#include <proc/task.h>	60	#include <proc/task.h>
61	#include <proc/thread.h>	61	#include <proc/thread.h>
62	#include <arch/asm.h>	62	#include <arch/asm.h>
63	#include <panic.h>	63	#include <panic.h>
64	#include <debug.h>	64	#include <debug.h>
65	#include <print.h>	65	#include <print.h>
66	#include <memstr.h>	66	#include <memstr.h>
67	#include <macros.h>	67	#include <macros.h>
68	#include <arch.h>	68	#include <arch.h>
69	#include <errno.h>	69	#include <errno.h>
70	#include <config.h>	70	#include <config.h>
71	#include <align.h>	71	#include <align.h>
72	#include <arch/types.h>	72	#include <arch/types.h>
73	#include <typedefs.h>	73	#include <typedefs.h>
74	#include <syscall/copy.h>	74	#include <syscall/copy.h>
75	#include <arch/interrupt.h>	75	#include <arch/interrupt.h>
76		76
-		77	/** This structure contains information associated with the shared address space area. */
-		78	struct share_info {
-		79	mutex_t lock; /*< This lock must be acquired only when the as_area lock is held. /
-		80	count_t refcount; /*< This structure can be deallocated if refcount drops to 0. /
-		81	btree_t pagemap; /*< B+tree containing complete map of anonymous pages of the shared area. /
-		82	};
-		83
77	as_operations_t *as_operations = NULL;	84	as_operations_t *as_operations = NULL;
78		85
79	/** Address space lock. It protects inactive_as_with_asid_head. Must be acquired before as_t mutex. */	86	/** Address space lock. It protects inactive_as_with_asid_head. Must be acquired before as_t mutex. */
80	SPINLOCK_INITIALIZE(as_lock);	87	SPINLOCK_INITIALIZE(as_lock);
81		88
82	/**	89	/**
83	* This list contains address spaces that are not active on any	90	* This list contains address spaces that are not active on any
84	* processor and that have valid ASID.	91	* processor and that have valid ASID.
85	*/	92	*/
86	LIST_INITIALIZE(inactive_as_with_asid_head);	93	LIST_INITIALIZE(inactive_as_with_asid_head);
87		94
88	/** Kernel address space. */	95	/** Kernel address space. */
89	as_t *AS_KERNEL = NULL;	96	as_t *AS_KERNEL = NULL;
90		97
91	static int area_flags_to_page_flags(int aflags);	98	static int area_flags_to_page_flags(int aflags);
92	static int get_area_flags(as_area_t *a);	-
93	static as_area_t find_area_and_lock(as_t as, __address va);	99	static as_area_t find_area_and_lock(as_t as, __address va);
94	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);	100	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);
95	static int used_space_insert(as_area_t *a, __address page, count_t count);	-
96	static int used_space_remove(as_area_t *a, __address page, count_t count);	101	static void sh_info_remove_reference(share_info_t *sh_info);
97		102
98	/** Initialize address space subsystem. */	103	/** Initialize address space subsystem. */
99	void as_init(void)	104	void as_init(void)
100	{	105	{
101	as_arch_init();	106	as_arch_init();
102	AS_KERNEL = as_create(FLAG_AS_KERNEL);	107	AS_KERNEL = as_create(FLAG_AS_KERNEL);
103	if (!AS_KERNEL)	108	if (!AS_KERNEL)
104	panic("can't create kernel address space\n");	109	panic("can't create kernel address space\n");
105		110
106	}	111	}
107		112
108	/** Create address space.	113	/** Create address space.
109	*	114	*
110	* @param flags Flags that influence way in wich the address space is created.	115	* @param flags Flags that influence way in wich the address space is created.
111	*/	116	*/
112	as_t *as_create(int flags)	117	as_t *as_create(int flags)
113	{	118	{
114	as_t *as;	119	as_t *as;
115		120
116	as = (as_t *) malloc(sizeof(as_t), 0);	121	as = (as_t *) malloc(sizeof(as_t), 0);
117	link_initialize(&as->inactive_as_with_asid_link);	122	link_initialize(&as->inactive_as_with_asid_link);
118	mutex_initialize(&as->lock);	123	mutex_initialize(&as->lock);
119	btree_create(&as->as_area_btree);	124	btree_create(&as->as_area_btree);
120		125
121	if (flags & FLAG_AS_KERNEL)	126	if (flags & FLAG_AS_KERNEL)
122	as->asid = ASID_KERNEL;	127	as->asid = ASID_KERNEL;
123	else	128	else
124	as->asid = ASID_INVALID;	129	as->asid = ASID_INVALID;
125		130
126	as->refcount = 0;	131	as->refcount = 0;
127	as->page_table = page_table_create(flags);	132	as->page_table = page_table_create(flags);
128		133
129	return as;	134	return as;
130	}	135	}
131		136
132	/** Free Adress space */	137	/** Free Adress space */
133	void as_free(as_t *as)	138	void as_free(as_t *as)
134	{	139	{
135	ASSERT(as->refcount == 0);	140	ASSERT(as->refcount == 0);
136		141
137	/* TODO: free as_areas and other resources held by as */	142	/* TODO: free as_areas and other resources held by as */
138	/* TODO: free page table */	143	/* TODO: free page table */
139	free(as);	144	free(as);
140	}	145	}
141		146
142	/** Create address space area of common attributes.	147	/** Create address space area of common attributes.
143	*	148	*
144	* The created address space area is added to the target address space.	149	* The created address space area is added to the target address space.
145	*	150	*
146	* @param as Target address space.	151	* @param as Target address space.
147	* @param flags Flags of the area memory.	152	* @param flags Flags of the area memory.
148	* @param size Size of area.	153	* @param size Size of area.
149	* @param base Base address of area.	154	* @param base Base address of area.
150	* @param attrs Attributes of the area.	155	* @param attrs Attributes of the area.
-		156	* @param backend Address space area backend. NULL if no backend is used.
-		157	* @param backend_data NULL or a pointer to an array holding two void *.
151	*	158	*
152	* @return Address space area on success or NULL on failure.	159	* @return Address space area on success or NULL on failure.
153	*/	160	*/
154	as_area_t as_area_create(as_t as, int flags, size_t size, __address base, int attrs)	161	as_area_t as_area_create(as_t as, int flags, size_t size, __address base, int attrs,
-		162	mem_backend_t backend, void *backend_data)
155	{	163	{
156	ipl_t ipl;	164	ipl_t ipl;
157	as_area_t *a;	165	as_area_t *a;
158		166
159	if (base % PAGE_SIZE)	167	if (base % PAGE_SIZE)
160	return NULL;	168	return NULL;
161		169
162	if (!size)	170	if (!size)
163	return NULL;	171	return NULL;
164		172
165	/* Writeable executable areas are not supported. */	173	/* Writeable executable areas are not supported. */
166	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))	174	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
167	return NULL;	175	return NULL;
168		176
169	ipl = interrupts_disable();	177	ipl = interrupts_disable();
170	mutex_lock(&as->lock);	178	mutex_lock(&as->lock);
171		179
172	if (!check_area_conflicts(as, base, size, NULL)) {	180	if (!check_area_conflicts(as, base, size, NULL)) {
173	mutex_unlock(&as->lock);	181	mutex_unlock(&as->lock);
174	interrupts_restore(ipl);	182	interrupts_restore(ipl);
175	return NULL;	183	return NULL;
176	}	184	}
177		185
178	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	186	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
179		187
180	mutex_initialize(&a->lock);	188	mutex_initialize(&a->lock);
181		189
182	a->flags = flags;	190	a->flags = flags;
183	a->attributes = attrs;	191	a->attributes = attrs;
184	a->pages = SIZE2FRAMES(size);	192	a->pages = SIZE2FRAMES(size);
185	a->base = base;	193	a->base = base;
-		194	a->sh_info = NULL;
-		195	a->backend = backend;
-		196	if (backend_data) {
-		197	a->backend_data[0] = backend_data[0];
-		198	a->backend_data[1] = backend_data[1];
-		199	}
186	btree_create(&a->used_space);	200	btree_create(&a->used_space);
187		201
188	btree_insert(&as->as_area_btree, base, (void *) a, NULL);	202	btree_insert(&as->as_area_btree, base, (void *) a, NULL);
189		203
190	mutex_unlock(&as->lock);	204	mutex_unlock(&as->lock);
191	interrupts_restore(ipl);	205	interrupts_restore(ipl);
192		206
193	return a;	207	return a;
194	}	208	}
195		209
196	/** Find address space area and change it.	210	/** Find address space area and change it.
197	*	211	*
198	* @param as Address space.	212	* @param as Address space.
199	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	213	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
200	* @param size New size of the virtual memory block starting at address.	214	* @param size New size of the virtual memory block starting at address.
201	* @param flags Flags influencing the remap operation. Currently unused.	215	* @param flags Flags influencing the remap operation. Currently unused.
202	*	216	*
203	* @return Zero on success or a value from @ref errno.h otherwise.	217	* @return Zero on success or a value from @ref errno.h otherwise.
204	*/	218	*/
205	int as_area_resize(as_t *as, __address address, size_t size, int flags)	219	int as_area_resize(as_t *as, __address address, size_t size, int flags)
206	{	220	{
207	as_area_t *area;	221	as_area_t *area;
208	ipl_t ipl;	222	ipl_t ipl;
209	size_t pages;	223	size_t pages;
210		224
211	ipl = interrupts_disable();	225	ipl = interrupts_disable();
212	mutex_lock(&as->lock);	226	mutex_lock(&as->lock);
213		227
214	/*	228	/*
215	* Locate the area.	229	* Locate the area.
216	*/	230	*/
217	area = find_area_and_lock(as, address);	231	area = find_area_and_lock(as, address);
218	if (!area) {	232	if (!area) {
219	mutex_unlock(&as->lock);	233	mutex_unlock(&as->lock);
220	interrupts_restore(ipl);	234	interrupts_restore(ipl);
221	return ENOENT;	235	return ENOENT;
222	}	236	}
223		237
224	if (area->flags & AS_AREA_DEVICE) {	238	if (area->flags & AS_AREA_DEVICE) {
225	/*	239	/*
226	* Remapping of address space areas associated	240	* Remapping of address space areas associated
227	* with memory mapped devices is not supported.	241	* with memory mapped devices is not supported.
228	*/	242	*/
229	mutex_unlock(&area->lock);	243	mutex_unlock(&area->lock);
230	mutex_unlock(&as->lock);	244	mutex_unlock(&as->lock);
231	interrupts_restore(ipl);	245	interrupts_restore(ipl);
232	return ENOTSUP;	246	return ENOTSUP;
233	}	247	}
-		248	if (area->sh_info) {
-		249	/*
-		250	* Remapping of shared address space areas
-		251	* is not supported.
-		252	*/
-		253	mutex_unlock(&area->lock);
-		254	mutex_unlock(&as->lock);
-		255	interrupts_restore(ipl);
-		256	return ENOTSUP;
-		257	}
234		258
235	pages = SIZE2FRAMES((address - area->base) + size);	259	pages = SIZE2FRAMES((address - area->base) + size);
236	if (!pages) {	260	if (!pages) {
237	/*	261	/*
238	* Zero size address space areas are not allowed.	262	* Zero size address space areas are not allowed.
239	*/	263	*/
240	mutex_unlock(&area->lock);	264	mutex_unlock(&area->lock);
241	mutex_unlock(&as->lock);	265	mutex_unlock(&as->lock);
242	interrupts_restore(ipl);	266	interrupts_restore(ipl);
243	return EPERM;	267	return EPERM;
244	}	268	}
245		269
246	if (pages < area->pages) {	270	if (pages < area->pages) {
247	bool cond;	271	bool cond;
248	__address start_free = area->base + pages*PAGE_SIZE;	272	__address start_free = area->base + pages*PAGE_SIZE;
249		273
250	/*	274	/*
251	* Shrinking the area.	275	* Shrinking the area.
252	* No need to check for overlaps.	276	* No need to check for overlaps.
253	*/	277	*/
254		278
255	/*	279	/*
256	* Remove frames belonging to used space starting from	280	* Remove frames belonging to used space starting from
257	* the highest addresses downwards until an overlap with	281	* the highest addresses downwards until an overlap with
258	* the resized address space area is found. Note that this	282	* the resized address space area is found. Note that this
259	* is also the right way to remove part of the used_space	283	* is also the right way to remove part of the used_space
260	* B+tree leaf list.	284	* B+tree leaf list.
261	*/	285	*/
262	for (cond = true; cond;) {	286	for (cond = true; cond;) {
263	btree_node_t *node;	287	btree_node_t *node;
264		288
265	ASSERT(!list_empty(&area->used_space.leaf_head));	289	ASSERT(!list_empty(&area->used_space.leaf_head));
266	node = list_get_instance(area->used_space.leaf_head.prev, btree_node_t, leaf_link);	290	node = list_get_instance(area->used_space.leaf_head.prev, btree_node_t, leaf_link);
267	if ((cond = (bool) node->keys)) {	291	if ((cond = (bool) node->keys)) {
268	__address b = node->key[node->keys - 1];	292	__address b = node->key[node->keys - 1];
269	count_t c = (count_t) node->value[node->keys - 1];	293	count_t c = (count_t) node->value[node->keys - 1];
270	int i = 0;	294	int i = 0;
271		295
272	if (overlaps(b, cPAGE_SIZE, area->base, pagesPAGE_SIZE)) {	296	if (overlaps(b, cPAGE_SIZE, area->base, pagesPAGE_SIZE)) {
273		297
274	if (b + c*PAGE_SIZE <= start_free) {	298	if (b + c*PAGE_SIZE <= start_free) {
275	/*	299	/*
276	* The whole interval fits completely	300	* The whole interval fits completely
277	* in the resized address space area.	301	* in the resized address space area.
278	*/	302	*/
279	break;	303	break;
280	}	304	}
281		305
282	/*	306	/*
283	* Part of the interval corresponding to b and c	307	* Part of the interval corresponding to b and c
284	* overlaps with the resized address space area.	308	* overlaps with the resized address space area.
285	*/	309	*/
286		310
287	cond = false; /* we are almost done */	311	cond = false; /* we are almost done */
288	i = (start_free - b) >> PAGE_WIDTH;	312	i = (start_free - b) >> PAGE_WIDTH;
289	if (!used_space_remove(area, start_free, c - i))	313	if (!used_space_remove(area, start_free, c - i))
290	panic("Could not remove used space.");	314	panic("Could not remove used space.");
291	} else {	315	} else {
292	/*	316	/*
293	* The interval of used space can be completely removed.	317	* The interval of used space can be completely removed.
294	*/	318	*/
295	if (!used_space_remove(area, b, c))	319	if (!used_space_remove(area, b, c))
296	panic("Could not remove used space.\n");	320	panic("Could not remove used space.\n");
297	}	321	}
298		322
299	for (; i < c; i++) {	323	for (; i < c; i++) {
300	pte_t *pte;	324	pte_t *pte;
301		325
302	page_table_lock(as, false);	326	page_table_lock(as, false);
303	pte = page_mapping_find(as, b + i*PAGE_SIZE);	327	pte = page_mapping_find(as, b + i*PAGE_SIZE);
304	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));	328	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
-		329	if (area->backend && area->backend->backend_frame_free) {
-		330	area->backend->backend_frame_free(area,
305	frame_free(ADDR2PFN(PTE_GET_FRAME(pte)));	331	b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
-		332	}
306	page_mapping_remove(as, b + i*PAGE_SIZE);	333	page_mapping_remove(as, b + i*PAGE_SIZE);
307	page_table_unlock(as, false);	334	page_table_unlock(as, false);
308	}	335	}
309	}	336	}
310	}	337	}
311	/*	338	/*
312	* Invalidate TLB's.	339	* Invalidate TLB's.
313	*/	340	*/
314	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	341	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
315	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	342	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
316	tlb_shootdown_finalize();	343	tlb_shootdown_finalize();
317	} else {	344	} else {
318	/*	345	/*
319	* Growing the area.	346	* Growing the area.
320	* Check for overlaps with other address space areas.	347	* Check for overlaps with other address space areas.
321	*/	348	*/
322	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {	349	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
323	mutex_unlock(&area->lock);	350	mutex_unlock(&area->lock);
324	mutex_unlock(&as->lock);	351	mutex_unlock(&as->lock);
325	interrupts_restore(ipl);	352	interrupts_restore(ipl);
326	return EADDRNOTAVAIL;	353	return EADDRNOTAVAIL;
327	}	354	}
328	}	355	}
329		356
330	area->pages = pages;	357	area->pages = pages;
331		358
332	mutex_unlock(&area->lock);	359	mutex_unlock(&area->lock);
333	mutex_unlock(&as->lock);	360	mutex_unlock(&as->lock);
334	interrupts_restore(ipl);	361	interrupts_restore(ipl);
335		362
336	return 0;	363	return 0;
337	}	364	}
338		365
339	/** Destroy address space area.	366	/** Destroy address space area.
340	*	367	*
341	* @param as Address space.	368	* @param as Address space.
342	* @param address Address withing the area to be deleted.	369	* @param address Address withing the area to be deleted.
343	*	370	*
344	* @return Zero on success or a value from @ref errno.h on failure.	371	* @return Zero on success or a value from @ref errno.h on failure.
345	*/	372	*/
346	int as_area_destroy(as_t *as, __address address)	373	int as_area_destroy(as_t *as, __address address)
347	{	374	{
348	as_area_t *area;	375	as_area_t *area;
349	__address base;	376	__address base;
350	ipl_t ipl;	377	ipl_t ipl;
351		378
352	ipl = interrupts_disable();	379	ipl = interrupts_disable();
353	mutex_lock(&as->lock);	380	mutex_lock(&as->lock);
354		381
355	area = find_area_and_lock(as, address);	382	area = find_area_and_lock(as, address);
356	if (!area) {	383	if (!area) {
357	mutex_unlock(&as->lock);	384	mutex_unlock(&as->lock);
358	interrupts_restore(ipl);	385	interrupts_restore(ipl);
359	return ENOENT;	386	return ENOENT;
360	}	387	}
361		388
362	base = area->base;	389	base = area->base;
363	if (!(area->flags & AS_AREA_DEVICE)) {	390	if (!(area->flags & AS_AREA_DEVICE)) {
364	bool cond;	391	bool cond;
365		392
366	/*	393	/*
367	* Releasing physical memory.	394	* Releasing physical memory.
368	* Areas mapping memory-mapped devices are treated differently than	395	* Areas mapping memory-mapped devices are treated differently than
369	* areas backing frame_alloc()'ed memory.	396	* areas backing frame_alloc()'ed memory.
370	*/	397	*/
371		398
372	/*	399	/*
373	* Visit only the pages mapped by used_space B+tree.	400	* Visit only the pages mapped by used_space B+tree.
374	* Note that we must be very careful when walking the tree	401	* Note that we must be very careful when walking the tree
375	* leaf list and removing used space as the leaf list changes	402	* leaf list and removing used space as the leaf list changes
376	* unpredictibly after each remove. The solution is to actually	403	* unpredictibly after each remove. The solution is to actually
377	* not walk the tree at all, but to remove items from the head	404	* not walk the tree at all, but to remove items from the head
378	* of the leaf list until there are some keys left.	405	* of the leaf list until there are some keys left.
379	*/	406	*/
380	for (cond = true; cond;) {	407	for (cond = true; cond;) {
381	btree_node_t *node;	408	btree_node_t *node;
382		409
383	ASSERT(!list_empty(&area->used_space.leaf_head));	410	ASSERT(!list_empty(&area->used_space.leaf_head));
384	node = list_get_instance(area->used_space.leaf_head.next, btree_node_t, leaf_link);	411	node = list_get_instance(area->used_space.leaf_head.next, btree_node_t, leaf_link);
385	if ((cond = (bool) node->keys)) {	412	if ((cond = (bool) node->keys)) {
386	__address b = node->key[0];	413	__address b = node->key[0];
387	count_t i;	414	count_t i;
388	pte_t *pte;	415	pte_t *pte;
389		416
390	for (i = 0; i < (count_t) node->value[0]; i++) {	417	for (i = 0; i < (count_t) node->value[0]; i++) {
391	page_table_lock(as, false);	418	page_table_lock(as, false);
392	pte = page_mapping_find(as, b + i*PAGE_SIZE);	419	pte = page_mapping_find(as, b + i*PAGE_SIZE);
393	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));	420	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
-		421	if (area->backend && area->backend->backend_frame_free) {
-		422	area->backend->backend_frame_free(area,
394	frame_free(ADDR2PFN(PTE_GET_FRAME(pte)));	423	b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
-		424	}
395	page_mapping_remove(as, b + i*PAGE_SIZE);	425	page_mapping_remove(as, b + i*PAGE_SIZE);
396	page_table_unlock(as, false);	426	page_table_unlock(as, false);
397	}	427	}
398	if (!used_space_remove(area, b, i))	428	if (!used_space_remove(area, b, i))
399	panic("Could not remove used space.\n");	429	panic("Could not remove used space.\n");
400	}	430	}
401	}	431	}
402	}	432	}
403	btree_destroy(&area->used_space);	433	btree_destroy(&area->used_space);
404		434
405	/*	435	/*
406	* Invalidate TLB's.	436	* Invalidate TLB's.
407	*/	437	*/
408	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);	438	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);
409	tlb_invalidate_pages(AS->asid, area->base, area->pages);	439	tlb_invalidate_pages(AS->asid, area->base, area->pages);
410	tlb_shootdown_finalize();	440	tlb_shootdown_finalize();
411		441
412	area->attributes \|= AS_AREA_ATTR_PARTIAL;	442	area->attributes \|= AS_AREA_ATTR_PARTIAL;
-		443
-		444	if (area->sh_info)
-		445	sh_info_remove_reference(area->sh_info);
-		446
413	mutex_unlock(&area->lock);	447	mutex_unlock(&area->lock);
414		448
415	/*	449	/*
416	* Remove the empty area from address space.	450	* Remove the empty area from address space.
417	*/	451	*/
418	btree_remove(&AS->as_area_btree, base, NULL);	452	btree_remove(&AS->as_area_btree, base, NULL);
419		453
420	free(area);	454	free(area);
421		455
422	mutex_unlock(&AS->lock);	456	mutex_unlock(&AS->lock);
423	interrupts_restore(ipl);	457	interrupts_restore(ipl);
424	return 0;	458	return 0;
425	}	459	}
426		460
427	/** Steal address space area from another task.	461	/** Steal address space area from another task.
428	*	462	*
429	* Address space area is stolen from another task	463	* Address space area is stolen from another task
430	* Moreover, any existing mapping	464	* Moreover, any existing mapping
431	* is copied as well, providing thus a mechanism	465	* is copied as well, providing thus a mechanism
432	* for sharing group of pages. The source address	466	* for sharing group of pages. The source address
433	* space area and any associated mapping is preserved.	467	* space area and any associated mapping is preserved.
434	*	468	*
435	* @param src_task Pointer of source task	469	* @param src_task Pointer of source task
436	* @param src_base Base address of the source address space area.	470	* @param src_base Base address of the source address space area.
437	* @param acc_size Expected size of the source area	471	* @param acc_size Expected size of the source area
438	* @param dst_base Target base address	472	* @param dst_base Target base address
439	*	473	*
440	* @return Zero on success or ENOENT if there is no such task or	474	* @return Zero on success or ENOENT if there is no such task or
441	* if there is no such address space area,	475	* if there is no such address space area,
442	* EPERM if there was a problem in accepting the area or	476	* EPERM if there was a problem in accepting the area or
443	* ENOMEM if there was a problem in allocating destination	477	* ENOMEM if there was a problem in allocating destination
444	* address space area.	478	* address space area.
445	*/	479	*/
446	int as_area_steal(task_t *src_task, __address src_base, size_t acc_size,	480	int as_area_steal(task_t *src_task, __address src_base, size_t acc_size,
447	__address dst_base)	481	__address dst_base)
448	{	482	{
449	ipl_t ipl;	483	ipl_t ipl;
450	count_t i;	484	count_t i;
451	as_t *src_as;	485	as_t *src_as;
452	int src_flags;	486	int src_flags;
453	size_t src_size;	487	size_t src_size;
454	as_area_t src_area, dst_area;	488	as_area_t src_area, dst_area;
455		489
456	ipl = interrupts_disable();	490	ipl = interrupts_disable();
457	spinlock_lock(&src_task->lock);	491	spinlock_lock(&src_task->lock);
458	src_as = src_task->as;	492	src_as = src_task->as;
459		493
460	mutex_lock(&src_as->lock);	494	mutex_lock(&src_as->lock);
461	src_area = find_area_and_lock(src_as, src_base);	495	src_area = find_area_and_lock(src_as, src_base);
462	if (!src_area) {	496	if (!src_area) {
463	/*	497	/*
464	* Could not find the source address space area.	498	* Could not find the source address space area.

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/mm/as.c @ 1705 – Rev 1403 → 1409