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/*
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/*
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 * Copyright (C) 2001-2004 Jakub Jermar
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 * Copyright (C) 2001-2004 Jakub Jermar
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 * All rights reserved.
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 * All rights reserved.
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 *
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * are met:
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 *
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 *
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 * - Redistributions of source code must retain the above copyright
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *   derived from this software without specific prior written permission.
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 *
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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 */
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#include <arch/types.h>
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#include <arch/types.h>
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#include <config.h>
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#include <config.h>
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#include <func.h>
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#include <func.h>
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#include <mm/frame.h>
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#include <mm/frame.h>
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#include <mm/page.h>
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#include <mm/page.h>
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#include <arch/mm/page.h>
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#include <arch/mm/page.h>
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#include <arch/interrupt.h>
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#include <arch/interrupt.h>
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#include <arch/asm.h>
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#include <arch/asm.h>
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#include <synch/spinlock.h>
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#include <synch/spinlock.h>
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#include <debug.h>
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#include <debug.h>
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/*
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/*
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 * Note.
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 * Note.
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 * This is the preliminary code for controlling paging mechanism on ia32. It is
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 * This is the preliminary code for controlling paging mechanism on ia32. It is
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 * needed by other parts of the kernel for its ability to map virtual addresses
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 * needed by other parts of the kernel for its ability to map virtual addresses
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 * to physical. SMP code relies on this feature. Other than that, this code is
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 * to physical. SMP code relies on this feature. Other than that, this code is
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 * by no means meant to implement virtual memory in terms of swapping pages in
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 * by no means meant to implement virtual memory in terms of swapping pages in
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 * and out.
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 * and out.
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 */
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 */
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__address bootstrap_dba;
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__address bootstrap_dba;
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void page_arch_init(void)
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void page_arch_init(void)
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{
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{
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    __address dba;
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    __address dba;
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    __u32 i;
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    __u32 i;
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    if (config.cpu_active == 1) {
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    if (config.cpu_active == 1) {
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        dba = frame_alloc(FRAME_KA | FRAME_PANIC);
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        dba = frame_alloc(FRAME_KA | FRAME_PANIC);
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        memsetb(dba, PAGE_SIZE, 0);
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        memsetb(dba, PAGE_SIZE, 0);
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        bootstrap_dba = dba;
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        bootstrap_dba = dba;
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        /*
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        /*
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         * Identity mapping for all frames.
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         * Identity mapping for all frames.
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         * PA2KA(identity) mapping for all frames.
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         * PA2KA(identity) mapping for all frames.
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         */
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         */
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        for (i = 0; i < frames; i++) {
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        for (i = 0; i < frames; i++) {
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            map_page_to_frame(i * PAGE_SIZE, i * PAGE_SIZE, PAGE_CACHEABLE, KA2PA(dba));
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            map_page_to_frame(i * PAGE_SIZE, i * PAGE_SIZE, PAGE_CACHEABLE, KA2PA(dba));
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            map_page_to_frame(PA2KA(i * PAGE_SIZE), i * PAGE_SIZE, PAGE_CACHEABLE, KA2PA(dba));
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            map_page_to_frame(PA2KA(i * PAGE_SIZE), i * PAGE_SIZE, PAGE_CACHEABLE, KA2PA(dba));
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        }
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        }
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        trap_register(14, page_fault);
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        trap_register(14, page_fault);
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        write_cr3(KA2PA(dba));
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        write_cr3(KA2PA(dba));
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    }
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    }
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    else {
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    else {
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        /*
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        /*
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         * Application processors need to create their own view of the
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         * Application processors need to create their own view of the
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         * virtual address space. Because of that, each AP copies
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         * virtual address space. Because of that, each AP copies
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         * already-initialized paging information from the bootstrap
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         * already-initialized paging information from the bootstrap
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         * processor and adjusts it to fulfill its needs.
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         * processor and adjusts it to fulfill its needs.
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         */
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         */
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        dba = frame_alloc(FRAME_KA | FRAME_PANIC);
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        dba = frame_alloc(FRAME_KA | FRAME_PANIC);
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        memcopy(bootstrap_dba, dba, PAGE_SIZE);
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        memcopy(bootstrap_dba, dba, PAGE_SIZE);
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        write_cr3(KA2PA(dba));
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        write_cr3(KA2PA(dba));
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    }
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    }
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    paging_on();
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    paging_on();
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}
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}
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 - 
 
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/*
 - 
 
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 * Besides mapping pages to frames, this function also sets the present bit of
 - 
 
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 * the page's specifier in both page directory and respective page table. If
 - 
 
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 * the page table for this page has not been allocated so far, it will take
 - 
 
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 * care of it and allocate the necessary frame.
 - 
 
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 *
 - 
 
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 * PAGE_CACHEABLE flag: when set, it turns caches for that page on
 - 
 
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 * PAGE_NOT_PRESENT flag: when set, it marks the page not present
 - 
 
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 * PAGE_USER flag: when set, the page is accessible from userspace
 - 
 
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 *
 - 
 
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 * When the root parameter is non-zero, it is used as the page directory address.
 - 
 
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 * Otherwise, the page directory address is read from CPU.
 - 
 
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 */
 - 
 
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void map_page_to_frame(__address page, __address frame, int flags, __address root)
 - 
 
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{
 - 
 
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    struct page_specifier *pd, *pt;
 - 
 
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    __address dba, newpt;
 - 
 
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    int pde, pte;
 - 
 
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 - 
 
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    if (root) dba = root;
 - 
 
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    else dba = read_cr3();
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 - 
 
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    pde = page >> 22;       /* page directory entry */
 - 
 
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    pte = (page >> 12) & 0x3ff; /* page table entry */
 - 
 
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 - 
 
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    pd = (struct page_specifier *) PA2KA(dba);
 - 
 
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 - 
 
117 
    if (!pd[pde].present) {
 - 
 
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        /*
 - 
 
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         * There is currently no page table for this address. Allocate
 - 
 
120 
         * frame for the page table and clean it.
 - 
 
121 
         */
 - 
 
122 
        newpt = frame_alloc(FRAME_KA);
 - 
 
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        pd[pde].frame_address = KA2PA(newpt) >> 12;
 - 
 
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        memsetb(newpt, PAGE_SIZE, 0);
 - 
 
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        pd[pde].present = 1;
 - 
 
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        pd[pde].uaccessible = 1;
 - 
 
127 
    }
 - 
 
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 - 
 
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    pt = (struct page_specifier *) PA2KA((pd[pde].frame_address << 12));
 - 
 
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 - 
 
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    pt[pte].frame_address = frame >> 12;
 - 
 
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    pt[pte].present = !(flags & PAGE_NOT_PRESENT);
 - 
 
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    pt[pte].page_cache_disable = !(flags & PAGE_CACHEABLE);
 - 
 
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    pt[pte].uaccessible = (flags & PAGE_USER) != 0;
 - 
 
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    pt[pte].writeable = (flags & PAGE_WRITE) != 0; 
 - 
 
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}
 - 
 
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