page.c

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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/mm/vhpt.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);

void page_arch_init(void)
{
        page_mapping_operations = &ht_mapping_operations;
        pk_disable();
        set_environment();
}

void set_environment(void)
{
        region_register rr;
        pta_register pta;       
        int i;
#ifdef CONFIG_VHPT      
        __address vhpt_base;
#endif

        /*
         * First set up kernel region register.
         * This is redundant (see start.S) but we keep it here just for sure.
         */
        rr.word = rr_read(VRN_KERNEL);
        rr.map.ve = 0;                  /* disable VHPT walker */
        rr.map.ps = PAGE_WIDTH;
        rr.map.rid = ASID2RID(ASID_KERNEL, VRN_KERNEL);
        rr_write(VRN_KERNEL, rr.word);
        srlz_i();
        srlz_d();

        /*
         * And setup 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 = RID_KERNEL;
                rr.map.ps = PAGE_WIDTH;
                rr_write(i, rr.word);
                srlz_i();
                srlz_d();
        }

#ifdef CONFIG_VHPT      
        vhpt_base = vhpt_set_up();
#endif
        /*
         * Set up PTA register.
         */
        pta.word = pta_read();
#ifndef CONFIG_VHPT
        pta.map.ve = 0;                   /* disable VHPT walker */
        pta.map.base = 0 >> PTA_BASE_SHIFT;
#else
        pta.map.ve = 1;                   /* enable VHPT walker */
        pta.map.base = vhpt_base >> PTA_BASE_SHIFT;
#endif
        pta.map.vf = 1;                   /* large entry format */
        pta.map.size = VHPT_WIDTH;
        pta_write(pta.word);
        srlz_i();
        srlz_d();
}

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;
}

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;           
}

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;
}

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