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/*

 * Copyright (C) 2006 Jakub Jermar

 * Copyright (C) 2006 Jakub Vana

 * 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.

 */

#include <arch/mm/page.h>

#include <genarch/mm/page_ht.h>

#include <mm/asid.h>

#include <arch/mm/asid.h>

#include <arch/types.h>

#include <typedefs.h>

#include <print.h>

#include <mm/page.h>

#include <mm/frame.h>

#include <config.h>

#include <panic.h>

#include <arch/asm.h>

#include <arch/barrier.h>

#include <memstr.h>

static void set_environment(void);

/** Initialize ia64 virtual address translation subsystem. */

void page_arch_init(void)

{

	page_operations = &page_ht_operations;

	pk_disable();

	set_environment();

}

/** Initialize VHPT and region registers. */

void set_environment(void)

{

	region_register rr;

	pta_register pta;	

	int i;

	/*

	 * First set up kernel region register.

	 */

	rr.word = rr_read(VRN_KERNEL);

	rr.map.ve = 0;                  /* disable VHPT walker */

	rr.map.ps = PAGE_WIDTH;

	rr.map.rid = ASID_KERNEL;

	rr_write(VRN_KERNEL, rr.word);

	srlz_i();

	srlz_d();

	/*

	 * And invalidate the rest of region register.

	 */

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

		/* skip kernel rr */

		if (i == VRN_KERNEL)

			continue;

		rr.word == rr_read(i);

		rr.map.ve = 0;		/* disable VHPT walker */

		rr.map.rid = ASID_INVALID;

		rr_write(i, rr.word);

		srlz_i();

		srlz_d();

	}

	/*

	 * Set up PTA register.

	 */

	pta.word = pta_read();

	pta.map.ve = 0;                   /* disable VHPT walker */

	pta.map.vf = 1;                   /* large entry format */

	pta.map.size = VHPT_WIDTH;

	pta.map.base = VHPT_BASE >> PTA_BASE_SHIFT;

	pta_write(pta.word);

	srlz_i();

	srlz_d();

}

/** Calculate address of collision chain from VPN and ASID.

 *

 * Interrupts must be disabled.

 *

 * @param page Address of virtual page including VRN bits.

 * @param asid Address space identifier.

 *

 * @return VHPT entry address.

 */

vhpt_entry_t *vhpt_hash(__address page, asid_t asid)

{

	region_register rr_save, rr;

	index_t vrn;

	rid_t rid;

	vhpt_entry_t *v;

	vrn = page >> VRN_SHIFT;

	rid = ASID2RID(asid, vrn);

	rr_save.word = rr_read(vrn);

	if (rr_save.map.rid == rid) {

		/*

		 * The RID is already in place, compute thash and return.

		 */

		v = (vhpt_entry_t *) thash(page);

		return v;

	}

	/*

	 * The RID must be written to some region register.

	 * To speed things up, register indexed by vrn is used.

	 */

	rr.word = rr_save.word;

	rr.map.rid = rid;

	rr_write(vrn, rr.word);

	srlz_i();

	v = (vhpt_entry_t *) thash(page);

	rr_write(vrn, rr_save.word);

	srlz_i();

	srlz_d();

	return v;

}

/** Compare ASID and VPN against PTE.

 *

 * Interrupts must be disabled.

 *

 * @param page Address of virtual page including VRN bits.

 * @param asid Address space identifier.

 *

 * @return True if page and asid match the page and asid of t, false otherwise.

 */

bool vhpt_compare(__address page, asid_t asid, vhpt_entry_t *v)

{

	region_register rr_save, rr;	

	index_t vrn;

	rid_t rid;

	bool match;

	ASSERT(v);

	vrn = page >> VRN_SHIFT;

	rid = ASID2RID(asid, vrn);

	rr_save.word = rr_read(vrn);

	if (rr_save.map.rid == rid) {

		/*

		 * The RID is already in place, compare ttag with t and return.

		 */

		return ttag(page) == v->present.tag.tag_word;

	}

	/*

	 * The RID must be written to some region register.

	 * To speed things up, register indexed by vrn is used.

	 */

	rr.word = rr_save.word;

	rr.map.rid = rid;

	rr_write(vrn, rr.word);

	srlz_i();

	match = (ttag(page) == v->present.tag.tag_word);

	rr_write(vrn, rr_save.word);

	srlz_i();

	srlz_d();

	return match;		

}

/** Set up one VHPT entry.

 *

 * @param t VHPT entry to be set up.

 * @param page Virtual address of the page mapped by the entry.

 * @param asid Address space identifier of the address space to which page belongs.

 * @param frame Physical address of the frame to wich page is mapped.

 * @param flags Different flags for the mapping.

 */

void vhpt_set_record(vhpt_entry_t *v, __address page, asid_t asid, __address frame, int flags)

{

	region_register rr_save, rr;	

	index_t vrn;

	rid_t rid;

	__u64 tag;

	ASSERT(v);

	vrn = page >> VRN_SHIFT;

	rid = ASID2RID(asid, vrn);

	/*

	 * Compute ttag.

	 */

	rr_save.word = rr_read(vrn);

	rr.word = rr_save.word;

	rr.map.rid = rid;

	rr_write(vrn, rr.word);

	srlz_i();

	tag = ttag(page);

	rr_write(vrn, rr_save.word);

	srlz_i();

	srlz_d();

	/*

	 * Clear the entry.

	 */

	v->word[0] = 0;

	v->word[1] = 0;

	v->word[2] = 0;

	v->word[3] = 0;

	v->present.p = true;

	v->present.ma = (flags & PAGE_CACHEABLE) ? MA_WRITEBACK : MA_UNCACHEABLE;

	v->present.a = false;	/* not accessed */

	v->present.d = false;	/* not dirty */

	v->present.pl = (flags & PAGE_USER) ? PL_USER : PL_KERNEL;

	v->present.ar = (flags & PAGE_WRITE) ? AR_WRITE : AR_READ;

	v->present.ar |= (flags & PAGE_EXEC) ? AR_EXECUTE : 0; 

	v->present.ppn = frame >> PPN_SHIFT;

	v->present.ed = false;	/* exception not deffered */

	v->present.ps = PAGE_WIDTH;

	v->present.key = 0;

	v->present.tag.tag_word = tag;

}