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>
 
as_operations_t *as_operations = NULL;
 
/** This lock protects inactive_as_with_asid_head list. It must be acquired before as_t mutex. */
SPINLOCK_INITIALIZE(inactive_as_with_asid_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->cpu_refcount = 0;
    as->page_table = page_table_create(flags);
 
    return as;
}
 
/** Free Adress space */
void as_free(as_t *as)
{
    ASSERT(as->cpu_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, mem_backend_data_t *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->as = as;
    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 = *backend_data;
    else
        memsetb((__address) &a->backend_data, sizeof(a->backend_data), 0);
 
    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->backend == &phys_backend) {
        /*
         * 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->frame_free) {
                        area->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;
    bool cond;
 
    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;
 
    /*
     * 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->frame_free) {
                    area->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;
}
 
/** Share address space area with another or the same address space.
 *
 * Address space area mapping is shared with a new address space area.
 * If the source address space area has not been shared so far,
 * a new sh_info is created. The new address space area simply gets the
 * sh_info of the source area. The process of duplicating the
 * mapping is done through the backend share function.
 *
 * @param src_as Pointer to source address space.
 * @param src_base Base address of the source address space area.
 * @param acc_size Expected size of the source area.
 * @param dst_as Pointer to destination address space.
 * @param dst_base Target base address.
 * @param dst_flags_mask Destination address space area flags mask.
 *
 * @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. ENOTSUP is returned if an attempt
 *     to share non-anonymous address space area is detected.
 */
int as_area_share(as_t *src_as, __address src_base, size_t acc_size,
          as_t *dst_as, __address dst_base, int dst_flags_mask)
{
    ipl_t ipl;
    int src_flags;
    size_t src_size;
    as_area_t *src_area, *dst_area;
    share_info_t *sh_info;
    mem_backend_t *src_backend;
    mem_backend_data_t src_backend_data;
 
    ipl = interrupts_disable();
    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.
         */
        mutex_unlock(&src_as->lock);
        interrupts_restore(ipl);
        return ENOENT;
    }
   
    if (!src_area->backend || !src_area->backend->share) {
        /*
         * There is now backend or the backend does not
         * know how to share the area.
         */
        mutex_unlock(&src_area->lock);
        mutex_unlock(&src_as->lock);
        interrupts_restore(ipl);
        return ENOTSUP;
    }
   
    src_size = src_area->pages * PAGE_SIZE;
    src_flags = src_area->flags;
    src_backend = src_area->backend;
    src_backend_data = src_area->backend_data;
   
    if (src_size != acc_size) {
        mutex_unlock(&src_area->lock);
        mutex_unlock(&src_as->lock);
        interrupts_restore(ipl);
        return EPERM;
    }
 
    /*
     * Now we are committed to sharing the area.
     * First prepare the area for sharing.
     * Then it will be safe to unlock it.
     */
    sh_info = src_area->sh_info;
    if (!sh_info) {
        sh_info = (share_info_t *) malloc(sizeof(share_info_t), 0);
        mutex_initialize(&sh_info->lock);
        sh_info->refcount = 2;
        btree_create(&sh_info->pagemap);
        src_area->sh_info = sh_info;
    } else {
        mutex_lock(&sh_info->lock);
        sh_info->refcount++;
        mutex_unlock(&sh_info->lock);
    }
 
    src_area->backend->share(src_area);
 
    mutex_unlock(&src_area->lock);
    mutex_unlock(&src_as->lock);
 
    /*
     * 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.
     * The flags of the source area are masked against dst_flags_mask
     * to support sharing in less privileged mode.
     */
    dst_area = as_area_create(dst_as, src_flags & dst_flags_mask, src_size, dst_base,
                  AS_AREA_ATTR_PARTIAL, src_backend, &src_backend_data);
    if (!dst_area) {
        /*
         * Destination address space area could not be created.
         */
        sh_info_remove_reference(sh_info);
       
        interrupts_restore(ipl);
        return ENOMEM;
    }
   
    /*
     * Now the destination address space area has been
     * fully initialized. Clear the AS_AREA_ATTR_PARTIAL
     * attribute and set the sh_info.
     */
    mutex_lock(&dst_area->lock);
    dst_area->attributes &= ~AS_AREA_ATTR_PARTIAL;
    dst_area->sh_info = sh_info;
    mutex_unlock(&dst_area->lock);
   
    interrupts_restore(ipl);
   
    return 0;
}
 
/** Check access mode for address space area.
 *
 * The address space area must be locked prior to this call.
 *
 * @param area Address space area.
 * @param access Access mode.
 *
 * @return False if access violates area's permissions, true otherwise.
 */
bool as_area_check_access(as_area_t *area, pf_access_t access)
{
    int flagmap[] = {
        [PF_ACCESS_READ] = AS_AREA_READ,
        [PF_ACCESS_WRITE] = AS_AREA_WRITE,
        [PF_ACCESS_EXEC] = AS_AREA_EXEC
    };
 
    if (!(area->flags & flagmap[access]))
        return false;
   
    return true;
}
 
/** 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 access Access mode that caused the fault (i.e. read/write/exec).
 * @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, pf_access_t access, 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->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)) {
            if (((access == PF_ACCESS_READ) && PTE_READABLE(pte)) ||
                (access == PF_ACCESS_WRITE && PTE_WRITABLE(pte)) ||
                (access == PF_ACCESS_EXEC && PTE_EXECUTABLE(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->page_fault(area, page, access) != 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
 * 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(&inactive_as_with_asid_lock);
 
    /*
     * First, take care of the old address space.
     */
    if (old) {
        mutex_lock_active(&old->lock);
        ASSERT(old->cpu_refcount);
        if((--old->cpu_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->cpu_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(&inactive_as_with_asid_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_CACHEABLE)
        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);
    }
}
 
/*
 * 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 | AS_AREA_CACHEABLE, 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 1424	Rev 1428
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	as_operations_t *as_operations = NULL;	77	as_operations_t *as_operations = NULL;
78		78
79	/** This lock protects inactive_as_with_asid_head list. It must be acquired before as_t mutex. */	79	/** This lock protects inactive_as_with_asid_head list. It must be acquired before as_t mutex. */
80	SPINLOCK_INITIALIZE(inactive_as_with_asid_lock);	80	SPINLOCK_INITIALIZE(inactive_as_with_asid_lock);
81		81
82	/**	82	/**
83	* This list contains address spaces that are not active on any	83	* This list contains address spaces that are not active on any
84	* processor and that have valid ASID.	84	* processor and that have valid ASID.
85	*/	85	*/
86	LIST_INITIALIZE(inactive_as_with_asid_head);	86	LIST_INITIALIZE(inactive_as_with_asid_head);
87		87
88	/** Kernel address space. */	88	/** Kernel address space. */
89	as_t *AS_KERNEL = NULL;	89	as_t *AS_KERNEL = NULL;
90		90
91	static int area_flags_to_page_flags(int aflags);	91	static int area_flags_to_page_flags(int aflags);
92	static as_area_t find_area_and_lock(as_t as, __address va);	92	static as_area_t find_area_and_lock(as_t as, __address va);
93	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);	93	static bool check_area_conflicts(as_t as, __address va, size_t size, as_area_t avoid_area);
94	static void sh_info_remove_reference(share_info_t *sh_info);	94	static void sh_info_remove_reference(share_info_t *sh_info);
95		95
96	/** Initialize address space subsystem. */	96	/** Initialize address space subsystem. */
97	void as_init(void)	97	void as_init(void)
98	{	98	{
99	as_arch_init();	99	as_arch_init();
100	AS_KERNEL = as_create(FLAG_AS_KERNEL);	100	AS_KERNEL = as_create(FLAG_AS_KERNEL);
101	if (!AS_KERNEL)	101	if (!AS_KERNEL)
102	panic("can't create kernel address space\n");	102	panic("can't create kernel address space\n");
103		103
104	}	104	}
105		105
106	/** Create address space.	106	/** Create address space.
107	*	107	*
108	* @param flags Flags that influence way in wich the address space is created.	108	* @param flags Flags that influence way in wich the address space is created.
109	*/	109	*/
110	as_t *as_create(int flags)	110	as_t *as_create(int flags)
111	{	111	{
112	as_t *as;	112	as_t *as;
113		113
114	as = (as_t *) malloc(sizeof(as_t), 0);	114	as = (as_t *) malloc(sizeof(as_t), 0);
115	link_initialize(&as->inactive_as_with_asid_link);	115	link_initialize(&as->inactive_as_with_asid_link);
116	mutex_initialize(&as->lock);	116	mutex_initialize(&as->lock);
117	btree_create(&as->as_area_btree);	117	btree_create(&as->as_area_btree);
118		118
119	if (flags & FLAG_AS_KERNEL)	119	if (flags & FLAG_AS_KERNEL)
120	as->asid = ASID_KERNEL;	120	as->asid = ASID_KERNEL;
121	else	121	else
122	as->asid = ASID_INVALID;	122	as->asid = ASID_INVALID;
123		123
124	as->cpu_refcount = 0;	124	as->cpu_refcount = 0;
125	as->page_table = page_table_create(flags);	125	as->page_table = page_table_create(flags);
126		126
127	return as;	127	return as;
128	}	128	}
129		129
130	/** Free Adress space */	130	/** Free Adress space */
131	void as_free(as_t *as)	131	void as_free(as_t *as)
132	{	132	{
133	ASSERT(as->cpu_refcount == 0);	133	ASSERT(as->cpu_refcount == 0);
134		134
135	/* TODO: free as_areas and other resources held by as */	135	/* TODO: free as_areas and other resources held by as */
136	/* TODO: free page table */	136	/* TODO: free page table */
137	free(as);	137	free(as);
138	}	138	}
139		139
140	/** Create address space area of common attributes.	140	/** Create address space area of common attributes.
141	*	141	*
142	* The created address space area is added to the target address space.	142	* The created address space area is added to the target address space.
143	*	143	*
144	* @param as Target address space.	144	* @param as Target address space.
145	* @param flags Flags of the area memory.	145	* @param flags Flags of the area memory.
146	* @param size Size of area.	146	* @param size Size of area.
147	* @param base Base address of area.	147	* @param base Base address of area.
148	* @param attrs Attributes of the area.	148	* @param attrs Attributes of the area.
149	* @param backend Address space area backend. NULL if no backend is used.	149	* @param backend Address space area backend. NULL if no backend is used.
150	* @param backend_data NULL or a pointer to an array holding two void *.	150	* @param backend_data NULL or a pointer to an array holding two void *.
151	*	151	*
152	* @return Address space area on success or NULL on failure.	152	* @return Address space area on success or NULL on failure.
153	*/	153	*/
154	as_area_t as_area_create(as_t as, int flags, size_t size, __address base, int attrs,	154	as_area_t as_area_create(as_t as, int flags, size_t size, __address base, int attrs,
155	mem_backend_t backend, mem_backend_data_t backend_data)	155	mem_backend_t backend, mem_backend_data_t backend_data)
156	{	156	{
157	ipl_t ipl;	157	ipl_t ipl;
158	as_area_t *a;	158	as_area_t *a;
159		159
160	if (base % PAGE_SIZE)	160	if (base % PAGE_SIZE)
161	return NULL;	161	return NULL;
162		162
163	if (!size)	163	if (!size)
164	return NULL;	164	return NULL;
165		165
166	/* Writeable executable areas are not supported. */	166	/* Writeable executable areas are not supported. */
167	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))	167	if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE))
168	return NULL;	168	return NULL;
169		169
170	ipl = interrupts_disable();	170	ipl = interrupts_disable();
171	mutex_lock(&as->lock);	171	mutex_lock(&as->lock);
172		172
173	if (!check_area_conflicts(as, base, size, NULL)) {	173	if (!check_area_conflicts(as, base, size, NULL)) {
174	mutex_unlock(&as->lock);	174	mutex_unlock(&as->lock);
175	interrupts_restore(ipl);	175	interrupts_restore(ipl);
176	return NULL;	176	return NULL;
177	}	177	}
178		178
179	a = (as_area_t *) malloc(sizeof(as_area_t), 0);	179	a = (as_area_t *) malloc(sizeof(as_area_t), 0);
180		180
181	mutex_initialize(&a->lock);	181	mutex_initialize(&a->lock);
182		182
183	a->as = as;	183	a->as = as;
184	a->flags = flags;	184	a->flags = flags;
185	a->attributes = attrs;	185	a->attributes = attrs;
186	a->pages = SIZE2FRAMES(size);	186	a->pages = SIZE2FRAMES(size);
187	a->base = base;	187	a->base = base;
188	a->sh_info = NULL;	188	a->sh_info = NULL;
189	a->backend = backend;	189	a->backend = backend;
190	if (backend_data)	190	if (backend_data)
191	a->backend_data = *backend_data;	191	a->backend_data = *backend_data;
192	else	192	else
193	memsetb((__address) &a->backend_data, sizeof(a->backend_data), 0);	193	memsetb((__address) &a->backend_data, sizeof(a->backend_data), 0);
194		194
195	btree_create(&a->used_space);	195	btree_create(&a->used_space);
196		196
197	btree_insert(&as->as_area_btree, base, (void *) a, NULL);	197	btree_insert(&as->as_area_btree, base, (void *) a, NULL);
198		198
199	mutex_unlock(&as->lock);	199	mutex_unlock(&as->lock);
200	interrupts_restore(ipl);	200	interrupts_restore(ipl);
201		201
202	return a;	202	return a;
203	}	203	}
204		204
205	/** Find address space area and change it.	205	/** Find address space area and change it.
206	*	206	*
207	* @param as Address space.	207	* @param as Address space.
208	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.	208	* @param address Virtual address belonging to the area to be changed. Must be page-aligned.
209	* @param size New size of the virtual memory block starting at address.	209	* @param size New size of the virtual memory block starting at address.
210	* @param flags Flags influencing the remap operation. Currently unused.	210	* @param flags Flags influencing the remap operation. Currently unused.
211	*	211	*
212	* @return Zero on success or a value from @ref errno.h otherwise.	212	* @return Zero on success or a value from @ref errno.h otherwise.
213	*/	213	*/
214	int as_area_resize(as_t *as, __address address, size_t size, int flags)	214	int as_area_resize(as_t *as, __address address, size_t size, int flags)
215	{	215	{
216	as_area_t *area;	216	as_area_t *area;
217	ipl_t ipl;	217	ipl_t ipl;
218	size_t pages;	218	size_t pages;
219		219
220	ipl = interrupts_disable();	220	ipl = interrupts_disable();
221	mutex_lock(&as->lock);	221	mutex_lock(&as->lock);
222		222
223	/*	223	/*
224	* Locate the area.	224	* Locate the area.
225	*/	225	*/
226	area = find_area_and_lock(as, address);	226	area = find_area_and_lock(as, address);
227	if (!area) {	227	if (!area) {
228	mutex_unlock(&as->lock);	228	mutex_unlock(&as->lock);
229	interrupts_restore(ipl);	229	interrupts_restore(ipl);
230	return ENOENT;	230	return ENOENT;
231	}	231	}
232		232
233	if (area->backend == &phys_backend) {	233	if (area->backend == &phys_backend) {
234	/*	234	/*
235	* Remapping of address space areas associated	235	* Remapping of address space areas associated
236	* with memory mapped devices is not supported.	236	* with memory mapped devices is not supported.
237	*/	237	*/
238	mutex_unlock(&area->lock);	238	mutex_unlock(&area->lock);
239	mutex_unlock(&as->lock);	239	mutex_unlock(&as->lock);
240	interrupts_restore(ipl);	240	interrupts_restore(ipl);
241	return ENOTSUP;	241	return ENOTSUP;
242	}	242	}
243	if (area->sh_info) {	243	if (area->sh_info) {
244	/*	244	/*
245	* Remapping of shared address space areas	245	* Remapping of shared address space areas
246	* is not supported.	246	* is not supported.
247	*/	247	*/
248	mutex_unlock(&area->lock);	248	mutex_unlock(&area->lock);
249	mutex_unlock(&as->lock);	249	mutex_unlock(&as->lock);
250	interrupts_restore(ipl);	250	interrupts_restore(ipl);
251	return ENOTSUP;	251	return ENOTSUP;
252	}	252	}
253		253
254	pages = SIZE2FRAMES((address - area->base) + size);	254	pages = SIZE2FRAMES((address - area->base) + size);
255	if (!pages) {	255	if (!pages) {
256	/*	256	/*
257	* Zero size address space areas are not allowed.	257	* Zero size address space areas are not allowed.
258	*/	258	*/
259	mutex_unlock(&area->lock);	259	mutex_unlock(&area->lock);
260	mutex_unlock(&as->lock);	260	mutex_unlock(&as->lock);
261	interrupts_restore(ipl);	261	interrupts_restore(ipl);
262	return EPERM;	262	return EPERM;
263	}	263	}
264		264
265	if (pages < area->pages) {	265	if (pages < area->pages) {
266	bool cond;	266	bool cond;
267	__address start_free = area->base + pages*PAGE_SIZE;	267	__address start_free = area->base + pages*PAGE_SIZE;
268		268
269	/*	269	/*
270	* Shrinking the area.	270	* Shrinking the area.
271	* No need to check for overlaps.	271	* No need to check for overlaps.
272	*/	272	*/
273		273
274	/*	274	/*
275	* Remove frames belonging to used space starting from	275	* Remove frames belonging to used space starting from
276	* the highest addresses downwards until an overlap with	276	* the highest addresses downwards until an overlap with
277	* the resized address space area is found. Note that this	277	* the resized address space area is found. Note that this
278	* is also the right way to remove part of the used_space	278	* is also the right way to remove part of the used_space
279	* B+tree leaf list.	279	* B+tree leaf list.
280	*/	280	*/
281	for (cond = true; cond;) {	281	for (cond = true; cond;) {
282	btree_node_t *node;	282	btree_node_t *node;
283		283
284	ASSERT(!list_empty(&area->used_space.leaf_head));	284	ASSERT(!list_empty(&area->used_space.leaf_head));
285	node = list_get_instance(area->used_space.leaf_head.prev, btree_node_t, leaf_link);	285	node = list_get_instance(area->used_space.leaf_head.prev, btree_node_t, leaf_link);
286	if ((cond = (bool) node->keys)) {	286	if ((cond = (bool) node->keys)) {
287	__address b = node->key[node->keys - 1];	287	__address b = node->key[node->keys - 1];
288	count_t c = (count_t) node->value[node->keys - 1];	288	count_t c = (count_t) node->value[node->keys - 1];
289	int i = 0;	289	int i = 0;
290		290
291	if (overlaps(b, cPAGE_SIZE, area->base, pagesPAGE_SIZE)) {	291	if (overlaps(b, cPAGE_SIZE, area->base, pagesPAGE_SIZE)) {
292		292
293	if (b + c*PAGE_SIZE <= start_free) {	293	if (b + c*PAGE_SIZE <= start_free) {
294	/*	294	/*
295	* The whole interval fits completely	295	* The whole interval fits completely
296	* in the resized address space area.	296	* in the resized address space area.
297	*/	297	*/
298	break;	298	break;
299	}	299	}
300		300
301	/*	301	/*
302	* Part of the interval corresponding to b and c	302	* Part of the interval corresponding to b and c
303	* overlaps with the resized address space area.	303	* overlaps with the resized address space area.
304	*/	304	*/
305		305
306	cond = false; /* we are almost done */	306	cond = false; /* we are almost done */
307	i = (start_free - b) >> PAGE_WIDTH;	307	i = (start_free - b) >> PAGE_WIDTH;
308	if (!used_space_remove(area, start_free, c - i))	308	if (!used_space_remove(area, start_free, c - i))
309	panic("Could not remove used space.");	309	panic("Could not remove used space.");
310	} else {	310	} else {
311	/*	311	/*
312	* The interval of used space can be completely removed.	312	* The interval of used space can be completely removed.
313	*/	313	*/
314	if (!used_space_remove(area, b, c))	314	if (!used_space_remove(area, b, c))
315	panic("Could not remove used space.\n");	315	panic("Could not remove used space.\n");
316	}	316	}
317		317
318	for (; i < c; i++) {	318	for (; i < c; i++) {
319	pte_t *pte;	319	pte_t *pte;
320		320
321	page_table_lock(as, false);	321	page_table_lock(as, false);
322	pte = page_mapping_find(as, b + i*PAGE_SIZE);	322	pte = page_mapping_find(as, b + i*PAGE_SIZE);
323	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));	323	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
324	if (area->backend && area->backend->frame_free) {	324	if (area->backend && area->backend->frame_free) {
325	area->backend->frame_free(area,	325	area->backend->frame_free(area,
326	b + i*PAGE_SIZE, PTE_GET_FRAME(pte));	326	b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
327	}	327	}
328	page_mapping_remove(as, b + i*PAGE_SIZE);	328	page_mapping_remove(as, b + i*PAGE_SIZE);
329	page_table_unlock(as, false);	329	page_table_unlock(as, false);
330	}	330	}
331	}	331	}
332	}	332	}
333	/*	333	/*
334	* Invalidate TLB's.	334	* Invalidate TLB's.
335	*/	335	*/
336	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	336	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
337	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);	337	tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages);
338	tlb_shootdown_finalize();	338	tlb_shootdown_finalize();
339	} else {	339	} else {
340	/*	340	/*
341	* Growing the area.	341	* Growing the area.
342	* Check for overlaps with other address space areas.	342	* Check for overlaps with other address space areas.
343	*/	343	*/
344	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {	344	if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) {
345	mutex_unlock(&area->lock);	345	mutex_unlock(&area->lock);
346	mutex_unlock(&as->lock);	346	mutex_unlock(&as->lock);
347	interrupts_restore(ipl);	347	interrupts_restore(ipl);
348	return EADDRNOTAVAIL;	348	return EADDRNOTAVAIL;
349	}	349	}
350	}	350	}
351		351
352	area->pages = pages;	352	area->pages = pages;
353		353
354	mutex_unlock(&area->lock);	354	mutex_unlock(&area->lock);
355	mutex_unlock(&as->lock);	355	mutex_unlock(&as->lock);
356	interrupts_restore(ipl);	356	interrupts_restore(ipl);
357		357
358	return 0;	358	return 0;
359	}	359	}
360		360
361	/** Destroy address space area.	361	/** Destroy address space area.
362	*	362	*
363	* @param as Address space.	363	* @param as Address space.
364	* @param address Address withing the area to be deleted.	364	* @param address Address withing the area to be deleted.
365	*	365	*
366	* @return Zero on success or a value from @ref errno.h on failure.	366	* @return Zero on success or a value from @ref errno.h on failure.
367	*/	367	*/
368	int as_area_destroy(as_t *as, __address address)	368	int as_area_destroy(as_t *as, __address address)
369	{	369	{
370	as_area_t *area;	370	as_area_t *area;
371	__address base;	371	__address base;
372	ipl_t ipl;	372	ipl_t ipl;
373	bool cond;	373	bool cond;
374		374
375	ipl = interrupts_disable();	375	ipl = interrupts_disable();
376	mutex_lock(&as->lock);	376	mutex_lock(&as->lock);
377		377
378	area = find_area_and_lock(as, address);	378	area = find_area_and_lock(as, address);
379	if (!area) {	379	if (!area) {
380	mutex_unlock(&as->lock);	380	mutex_unlock(&as->lock);
381	interrupts_restore(ipl);	381	interrupts_restore(ipl);
382	return ENOENT;	382	return ENOENT;
383	}	383	}
384		384
385	base = area->base;	385	base = area->base;
386		386
387	/*	387	/*
388	* Visit only the pages mapped by used_space B+tree.	388	* Visit only the pages mapped by used_space B+tree.
389	* Note that we must be very careful when walking the tree	389	* Note that we must be very careful when walking the tree
390	* leaf list and removing used space as the leaf list changes	390	* leaf list and removing used space as the leaf list changes
391	* unpredictibly after each remove. The solution is to actually	391	* unpredictibly after each remove. The solution is to actually
392	* not walk the tree at all, but to remove items from the head	392	* not walk the tree at all, but to remove items from the head
393	* of the leaf list until there are some keys left.	393	* of the leaf list until there are some keys left.
394	*/	394	*/
395	for (cond = true; cond;) {	395	for (cond = true; cond;) {
396	btree_node_t *node;	396	btree_node_t *node;
397		397
398	ASSERT(!list_empty(&area->used_space.leaf_head));	398	ASSERT(!list_empty(&area->used_space.leaf_head));
399	node = list_get_instance(area->used_space.leaf_head.next, btree_node_t, leaf_link);	399	node = list_get_instance(area->used_space.leaf_head.next, btree_node_t, leaf_link);
400	if ((cond = (bool) node->keys)) {	400	if ((cond = (bool) node->keys)) {
401	__address b = node->key[0];	401	__address b = node->key[0];
402	count_t i;	402	count_t i;
403	pte_t *pte;	403	pte_t *pte;
404		404
405	for (i = 0; i < (count_t) node->value[0]; i++) {	405	for (i = 0; i < (count_t) node->value[0]; i++) {
406	page_table_lock(as, false);	406	page_table_lock(as, false);
407	pte = page_mapping_find(as, b + i*PAGE_SIZE);	407	pte = page_mapping_find(as, b + i*PAGE_SIZE);
408	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));	408	ASSERT(pte && PTE_VALID(pte) && PTE_PRESENT(pte));
409	if (area->backend && area->backend->frame_free) {	409	if (area->backend && area->backend->frame_free) {
410	area->backend->frame_free(area,	410	area->backend->frame_free(area,
411	b + i*PAGE_SIZE, PTE_GET_FRAME(pte));	411	b + i*PAGE_SIZE, PTE_GET_FRAME(pte));
412	}	412	}
413	page_mapping_remove(as, b + i*PAGE_SIZE);	413	page_mapping_remove(as, b + i*PAGE_SIZE);
414	page_table_unlock(as, false);	414	page_table_unlock(as, false);
415	}	415	}
416	if (!used_space_remove(area, b, i))	416	if (!used_space_remove(area, b, i))
417	panic("Could not remove used space.\n");	417	panic("Could not remove used space.\n");
418	}	418	}
419	}	419	}
420	btree_destroy(&area->used_space);	420	btree_destroy(&area->used_space);
421		421
422	/*	422	/*
423	* Invalidate TLB's.	423	* Invalidate TLB's.
424	*/	424	*/
425	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);	425	tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base, area->pages);
426	tlb_invalidate_pages(AS->asid, area->base, area->pages);	426	tlb_invalidate_pages(AS->asid, area->base, area->pages);
427	tlb_shootdown_finalize();	427	tlb_shootdown_finalize();
428		428
429	area->attributes \|= AS_AREA_ATTR_PARTIAL;	429	area->attributes \|= AS_AREA_ATTR_PARTIAL;
430		430
431	if (area->sh_info)	431	if (area->sh_info)
432	sh_info_remove_reference(area->sh_info);	432	sh_info_remove_reference(area->sh_info);
433		433
434	mutex_unlock(&area->lock);	434	mutex_unlock(&area->lock);
435		435
436	/*	436	/*
437	* Remove the empty area from address space.	437	* Remove the empty area from address space.
438	*/	438	*/
439	btree_remove(&AS->as_area_btree, base, NULL);	439	btree_remove(&AS->as_area_btree, base, NULL);
440		440
441	free(area);	441	free(area);
442		442
443	mutex_unlock(&AS->lock);	443	mutex_unlock(&AS->lock);
444	interrupts_restore(ipl);	444	interrupts_restore(ipl);
445	return 0;	445	return 0;
446	}	446	}
447		447
448	/** Share address space area with another or the same address space.	448	/** Share address space area with another or the same address space.
449	*	449	*
450	* Address space area mapping is shared with a new address space area.	450	* Address space area mapping is shared with a new address space area.
451	* If the source address space area has not been shared so far,	451	* If the source address space area has not been shared so far,
452	* a new sh_info is created. The new address space area simply gets the	452	* a new sh_info is created. The new address space area simply gets the
453	* sh_info of the source area. The process of duplicating the	453	* sh_info of the source area. The process of duplicating the
454	* mapping is done through the backend share function.	454	* mapping is done through the backend share function.
455	*	455	*
456	* @param src_as Pointer to source address space.	456	* @param src_as Pointer to source address space.
457	* @param src_base Base address of the source address space area.	457	* @param src_base Base address of the source address space area.
458	* @param acc_size Expected size of the source area.	458	* @param acc_size Expected size of the source area.
-		459	* @param dst_as Pointer to destination address space.
459	* @param dst_base Target base address.	460	* @param dst_base Target base address.
460	* @param dst_flags_mask Destination address space area flags mask.	461	* @param dst_flags_mask Destination address space area flags mask.
461	*	462	*
462	* @return Zero on success or ENOENT if there is no such task or	463	* @return Zero on success or ENOENT if there is no such task or
463	* if there is no such address space area,	464	* if there is no such address space area,
464	* EPERM if there was a problem in accepting the area or	465	* EPERM if there was a problem in accepting the area or
465	* ENOMEM if there was a problem in allocating destination	466	* ENOMEM if there was a problem in allocating destination
466	* address space area. ENOTSUP is returned if an attempt	467	* address space area. ENOTSUP is returned if an attempt
467	* to share non-anonymous address space area is detected.	468	* to share non-anonymous address space area is detected.
468	*/	469	*/
469	int as_area_share(as_t *src_as, __address src_base, size_t acc_size,	470	int as_area_share(as_t *src_as, __address src_base, size_t acc_size,
470	__address dst_base, int dst_flags_mask)	471	as_t *dst_as, __address dst_base, int dst_flags_mask)
471	{	472	{
472	ipl_t ipl;	473	ipl_t ipl;
473	int src_flags;	474	int src_flags;
474	size_t src_size;	475	size_t src_size;
475	as_area_t src_area, dst_area;	476	as_area_t src_area, dst_area;
476	share_info_t *sh_info;	477	share_info_t *sh_info;
477	mem_backend_t *src_backend;	478	mem_backend_t *src_backend;
478	mem_backend_data_t src_backend_data;	479	mem_backend_data_t src_backend_data;
479		480
480	ipl = interrupts_disable();	481	ipl = interrupts_disable();
481	mutex_lock(&src_as->lock);	482	mutex_lock(&src_as->lock);
482	src_area = find_area_and_lock(src_as, src_base);	483	src_area = find_area_and_lock(src_as, src_base);
483	if (!src_area) {	484	if (!src_area) {
484	/*	485	/*
485	* Could not find the source address space area.	486	* Could not find the source address space area.
486	*/	487	*/
487	mutex_unlock(&src_as->lock);	488	mutex_unlock(&src_as->lock);
488	interrupts_restore(ipl);	489	interrupts_restore(ipl);
489	return ENOENT;	490	return ENOENT;
490	}	491	}
491		492
492	if (!src_area->backend \|\| !src_area->backend->share) {	493	if (!src_area->backend \|\| !src_area->backend->share) {
493	/*	494	/*
494	* There is now backend or the backend does not	495	* There is now backend or the backend does not
495	* know how to share the area.	496	* know how to share the area.
496	*/	497	*/
497	mutex_unlock(&src_area->lock);	498	mutex_unlock(&src_area->lock);
498	mutex_unlock(&src_as->lock);	499	mutex_unlock(&src_as->lock);
499	interrupts_restore(ipl);	500	interrupts_restore(ipl);

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(root)/kernel/trunk/generic/src/mm/as.c – Rev 1424 → 1428