| 0,0 → 1,139 |
|---|
| /* |
| * Copyright (C) 2001-2004 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. |
| */ |
| |
| #include <arch/types.h> |
| #include <config.h> |
| #include <func.h> |
| #include <mm/frame.h> |
| #include <mm/page.h> |
| #include <arch/mm/page.h> |
| #include <arch/interrupt.h> |
| #include <arch/asm.h> |
| #include <synch/spinlock.h> |
| |
| /* |
| * Note. |
| * This is the preliminary code for controlling paging mechanism on i386. It is |
| * needed by other parts of the kernel for its ability to map virtual addresses |
| * to physical. SMP code relies on this feature. Other than that, this code is |
| * by no means meant to implement virtual memory in terms of swapping pages in |
| * and out. |
| */ |
| |
| __address bootstrap_dba; |
| |
| void page_arch_init(void) |
| { |
| __address dba; |
| __u32 i; |
| |
| if (config.cpu_active == 1) { |
| dba = frame_alloc(FRAME_KA | FRAME_PANIC); |
| memsetb(dba, PAGE_SIZE, 0); |
| cpu_write_dba(dba); |
| |
| bootstrap_dba = dba; |
| |
| /* |
| * Identity mapping for all but 0th page. |
| */ |
| for (i = 1; i < frames; i++) |
| map_page_to_frame(i * PAGE_SIZE, i * PAGE_SIZE, PAGE_CACHEABLE, 0); |
| |
| trap_register(14, page_fault); |
| } |
| else { |
| |
| /* |
| * Application processors need to create their own view of the |
| * virtual address space. Because of that, each AP copies |
| * already-initialized paging information from the bootstrap |
| * processor and adjusts it to fulfill its needs. |
| */ |
| |
| dba = frame_alloc(FRAME_KA | FRAME_PANIC); |
| memcopy(bootstrap_dba, dba, PAGE_SIZE); |
| cpu_write_dba(dba); |
| } |
| |
| paging_on(); |
| } |
| |
| /* |
| * Besides mapping pages to frames, this function also sets the present bit of |
| * the page's specifier in both page directory and respective page table. If |
| * the page table for this page has not been allocated so far, it will take |
| * care of it and allocate the necessary frame. |
| * |
| * When the copy parameter is positive, map_page_to_frame will not overwrite |
| * the current mapping. It will allocate a new frame and do the mapping on it |
| * instead. |
| * |
| * PAGE_CACHEABLE flag: when set, it turns caches for that page on |
| * PAGE_NOT_PRESENT flag: when set, it marks the page not present |
| * PAGE_USER flag: when set, the page is accessible from userspace |
| */ |
| void map_page_to_frame(__address page, __address frame, int flags, int copy) |
| { |
| struct page_specifier *pd, *pt; |
| __address dba, newpt; |
| int pde, pte; |
| |
| dba = cpu_read_dba(); |
| |
| pde = page >> 22; /* page directory entry */ |
| pte = (page >> 12) & 0x3ff; /* page table entry */ |
| |
| pd = (struct page_specifier *) dba; |
| |
| if (!pd[pde].present) { |
| /* |
| * There is currently no page table for this address. Allocate |
| * frame for the page table and clean it. |
| */ |
| newpt = frame_alloc(FRAME_KA); |
| pd[pde].frame_address = newpt >> 12; |
| memsetb(newpt, PAGE_SIZE, 0); |
| pd[pde].present = 1; |
| pd[pde].uaccessible = 1; |
| } |
| if (copy) { |
| newpt = frame_alloc(FRAME_KA); |
| memcopy(pd[pde].frame_address << 12, newpt, PAGE_SIZE); |
| pd[pde].frame_address = newpt >> 12; |
| } |
| pt = (struct page_specifier *) (pd[pde].frame_address << 12); |
| |
| pt[pte].frame_address = frame >> 12; |
| pt[pte].present = !(flags & PAGE_NOT_PRESENT); |
| pt[pte].page_cache_disable = !(flags & PAGE_CACHEABLE); |
| pt[pte].uaccessible = (flags & PAGE_USER) != 0; |
| pt[pte].writeable = (flags & PAGE_WRITE) != 0; |
| |
| tlb_invalidate(0); |
| } |