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/*

 * Copyright (C) 2001-2006 Jakub Jermar

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * - Redistributions of source code must retain the above copyright

 *   notice, this list of conditions and the following disclaimer.

 * - Redistributions in binary form must reproduce the above copyright

 *   notice, this list of conditions and the following disclaimer in the

 *   documentation and/or other materials provided with the distribution.

 * - The name of the author may not be used to endorse or promote products

 *   derived from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/*

 * This file contains address space manipulation functions.

 * Roughly speaking, this is a higher-level client of

 * Virtual Address Translation (VAT) subsystem.

 */

#include <mm/as.h>

#include <mm/asid.h>

#include <mm/page.h>

#include <mm/frame.h>

#include <mm/tlb.h>

#include <mm/heap.h>

#include <arch/mm/page.h>

#include <genarch/mm/page_pt.h>

#include <mm/asid.h>

#include <arch/mm/asid.h>

#include <arch/mm/as.h>

#include <arch/types.h>

#include <typedefs.h>

#include <synch/spinlock.h>

#include <config.h>

#include <list.h>

#include <panic.h>

#include <arch/asm.h>

#include <debug.h>

#include <memstr.h>

#include <arch.h>

#include <print.h>

#define KAS_START_INDEX		PTL0_INDEX(KERNEL_ADDRESS_SPACE_START)

#define KAS_END_INDEX		PTL0_INDEX(KERNEL_ADDRESS_SPACE_END)

#define KAS_INDICES		(1+(KAS_END_INDEX-KAS_START_INDEX))

/*

 * Here we assume that PFN (Physical Frame Number) space

 * is smaller than the width of index_t. UNALLOCATED_PFN

 * can be then used to mark mappings wich were not

 * yet allocated a physical frame.

 */

#define UNALLOCATED_PFN		((index_t) -1)

/** Create address space. */

/*

 * FIXME: this interface must be meaningful for all possible VAT

 * 	  (Virtual Address Translation) mechanisms.

 */

as_t *as_create(pte_t *ptl0, int flags)

{

	as_t *as;

	as = (as_t *) malloc(sizeof(as_t));

	if (as) {

		list_initialize(&as->as_with_asid_link);

		spinlock_initialize(&as->lock, "as_lock");

		list_initialize(&as->as_area_head);

		if (flags & AS_KERNEL)

			as->asid = ASID_KERNEL;

		else

			as->asid = ASID_INVALID;

		as->ptl0 = ptl0;

		if (!as->ptl0) {

			pte_t *src_ptl0, *dst_ptl0;

			src_ptl0 = (pte_t *) PA2KA((__address) GET_PTL0_ADDRESS());

			dst_ptl0 = (pte_t *) frame_alloc(FRAME_KA | FRAME_PANIC, ONE_FRAME, NULL);

//			memsetb((__address) dst_ptl0, PAGE_SIZE, 0);

//			memcpy((void *) &dst_ptl0[KAS_START_INDEX], (void *) &src_ptl0[KAS_START_INDEX], KAS_INDICES);

			memcpy((void *) dst_ptl0,(void *) src_ptl0, PAGE_SIZE);

			as->ptl0 = (pte_t *) KA2PA((__address) dst_ptl0);

		}

	}

	return 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 type Type of area.

 * @param size Size of area in multiples of PAGE_SIZE.

 * @param base Base address of area.

 *

 * @return Address space area on success or NULL on failure.

 */

as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base)

{

	ipl_t ipl;

	as_area_t *a;

	if (base % PAGE_SIZE)

		panic("addr not aligned to a page boundary");

	ipl = interrupts_disable();

	spinlock_lock(&as->lock);

	/*

	 * TODO: test as_area which is to be created doesn't overlap with an existing one.

	 */

	a = (as_area_t *) malloc(sizeof(as_area_t));

	if (a) {

		int i;

		a->mapping = (index_t *) malloc(size * sizeof(index_t));

		if (!a->mapping) {

			free(a);

			spinlock_unlock(&as->lock);

			interrupts_restore(ipl);

			return NULL;

		}

		for (i=0; i<size; i++) {

			/*

			 * Frames will be allocated on-demand by

			 * as_page_fault() or preloaded by

			 * as_area_set_mapping().

			 */

			a->mapping[i] = UNALLOCATED_PFN;

		}

		spinlock_initialize(&a->lock, "as_area_lock");

		link_initialize(&a->link);			

		a->type = type;

		a->size = size;

		a->base = base;

		list_append(&a->link, &as->as_area_head);

	}

	spinlock_unlock(&as->lock);

	interrupts_restore(ipl);

	return a;

}

/** Load mapping for address space area.

 *

 * Initialize a->mapping.

 *

 * @param a   Target address space area.

 * @param vpn Page number relative to area start.

 * @param pfn Frame number to map.

 */

void as_area_set_mapping(as_area_t *a, index_t vpn, index_t pfn)

{

	ASSERT(vpn < a->size);

	ASSERT(a->mapping[vpn] == UNALLOCATED_PFN);

	ASSERT(pfn != UNALLOCATED_PFN);

	ipl_t ipl;

	ipl = interrupts_disable();

	spinlock_lock(&a->lock);

	a->mapping[vpn] = pfn;

	spinlock_unlock(&a->lock);

	interrupts_restore(ipl);

}

/** Handle page fault within the current address space.

 *

 * This is the high-level page fault handler.

 * Interrupts are assumed disabled.

 *

 * @param page Faulting page.

 *

 * @return 0 on page fault, 1 on success.

 */

int as_page_fault(__address page)

{

	int flags;

	link_t *cur;

	as_area_t *a, *area = NULL;

	index_t vpn;

	__address frame;

	ASSERT(AS);

	spinlock_lock(&AS->lock);

	/*

	 * Search this areas of this address space for presence of 'page'.

	 */

	for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {

		a = list_get_instance(cur, as_area_t, link);

		spinlock_lock(&a->lock);

		if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {

			/*

			 * We found the area containing 'page'.

			 * TODO: access checking

			 */

			vpn = (page - a->base) / PAGE_SIZE;

			area = a;

			break;

		}

		spinlock_unlock(&a->lock);

	}

	if (!area) {

		/*

		 * No area contained mapping for 'page'.

		 * Signal page fault to low-level handler.

		 */

		spinlock_unlock(&AS->lock);

		return 0;

	}

	/*

	 * Note: area->lock is held.

	 */

	/*

	 * Decide if a frame needs to be allocated.

	 * If so, allocate it and adjust area->mapping map.

	 */

	if (area->mapping[vpn] == UNALLOCATED_PFN) {

		frame = frame_alloc(0, ONE_FRAME, NULL);

		memsetb(PA2KA(frame), FRAME_SIZE, 0);

		area->mapping[vpn] = frame / FRAME_SIZE;

		ASSERT(area->mapping[vpn] != UNALLOCATED_PFN);

	} else

		frame = area->mapping[vpn] * FRAME_SIZE;

	switch (area->type) {

		case AS_AREA_TEXT:

			flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;

			break;

		case AS_AREA_DATA:

		case AS_AREA_STACK:

			flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;

			break;

		default:

			panic("unexpected as_area_type_t %d", area->type);

	}

	/*

	 * Map 'page' to 'frame'.

	 * Note that TLB shootdown is not attempted as only new information is being

	 * inserted into page tables.

	 */

	page_mapping_insert(page, AS->asid, frame, flags, (__address) AS->ptl0);

	spinlock_unlock(&area->lock);

	spinlock_unlock(&AS->lock);

	return 1;

}

/** Install address space on CPU.

 *

 * @param as Address space.

 */

void as_install(as_t *as)

{

	ipl_t ipl;

	asid_install(as);

	ipl = interrupts_disable();

	spinlock_lock(&as->lock);

	ASSERT(as->ptl0);

	SET_PTL0_ADDRESS(as->ptl0);

	spinlock_unlock(&as->lock);

	interrupts_restore(ipl);

	/*

	 * Perform architecture-specific steps.

	 * (e.g. write ASID to hardware register etc.)

	 */

	as_install_arch(as);

	AS = as;

}