/*
 * Copyright 2008-2010, Ingo Weinhold, ingo_weinhold@gmx.de.
 * Copyright 2002-2007, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
 * Distributed under the terms of the MIT License.
 *
 * Copyright 2001-2002, Travis Geiselbrecht. All rights reserved.
 * Distributed under the terms of the NewOS License.
 */


#include "paging/32bit/ARMPagingStructures32Bit.h"

#include <stdlib.h>

#include <heap.h>
#include <util/AutoLock.h>


// Accessor class to reuse the SinglyLinkedListLink of DeferredDeletable for
// ARMPagingStructures32Bit.
struct PagingStructuresGetLink {
private:
        typedef SinglyLinkedListLink<ARMPagingStructures32Bit> Link;

public:
        inline Link* operator()(ARMPagingStructures32Bit* element) const
        {
                return (Link*)element->GetSinglyLinkedListLink();
        }

        inline const Link* operator()(
                const ARMPagingStructures32Bit* element) const
        {
                return (const Link*)element->GetSinglyLinkedListLink();
        }
};


typedef SinglyLinkedList<ARMPagingStructures32Bit, PagingStructuresGetLink>
        PagingStructuresList;


static PagingStructuresList sPagingStructuresList;
static spinlock sPagingStructuresListLock;


ARMPagingStructures32Bit::ARMPagingStructures32Bit()
        :
        pgdir_virt(NULL)
{
}


ARMPagingStructures32Bit::~ARMPagingStructures32Bit()
{
        // free the page dir
        free(pgdir_virt);
}


void
ARMPagingStructures32Bit::Init(page_directory_entry* virtualPageDir,
        phys_addr_t physicalPageDir, page_directory_entry* kernelPageDir)
{
        pgdir_virt = virtualPageDir;
        pgdir_phys = physicalPageDir;

        // zero out the bottom portion of the new pgdir
        memset(pgdir_virt + FIRST_USER_PGDIR_ENT, 0,
                NUM_USER_PGDIR_ENTS * sizeof(page_directory_entry));

        // insert this new map into the map list
        {
                int state = disable_interrupts();
                acquire_spinlock(&sPagingStructuresListLock);

                // copy the top portion of the page dir from the kernel page dir
                if (kernelPageDir != NULL) {
                        memcpy(pgdir_virt + FIRST_KERNEL_PGDIR_ENT,
                                kernelPageDir + FIRST_KERNEL_PGDIR_ENT,
                                NUM_KERNEL_PGDIR_ENTS * sizeof(page_directory_entry));
                }

                sPagingStructuresList.Add(this);

                release_spinlock(&sPagingStructuresListLock);
                restore_interrupts(state);
        }
}


void
ARMPagingStructures32Bit::Delete()
{
        // remove from global list
        InterruptsSpinLocker locker(sPagingStructuresListLock);
        sPagingStructuresList.Remove(this);
        locker.Unlock();

#if 0
        // this sanity check can be enabled when corruption due to
        // overwriting an active page directory is suspected
        uint32 activePageDirectory = x86_read_cr3();
        if (activePageDirectory == pgdir_phys)
                panic("deleting a still active page directory\n");
#endif

        if (are_interrupts_enabled())
                delete this;
        else
                deferred_delete(this);
}


/*static*/ void
ARMPagingStructures32Bit::StaticInit()
{
        B_INITIALIZE_SPINLOCK(&sPagingStructuresListLock);
        new (&sPagingStructuresList) PagingStructuresList;
}


/*static*/ void
ARMPagingStructures32Bit::UpdateAllPageDirs(int index,
        page_directory_entry entry)
{
        InterruptsSpinLocker locker(sPagingStructuresListLock);

        PagingStructuresList::ConstIterator it = sPagingStructuresList.GetIterator();
        while (ARMPagingStructures32Bit* info = it.Next())
                info->pgdir_virt[index] = entry;
}