105 lines
3.2 KiB
C++
105 lines
3.2 KiB
C++
/******************************************************************************
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COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along
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with Sortix. If not, see <http://www.gnu.org/licenses/>.
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memorymanagement.cpp
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Handles memory for the x86 architecture.
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******************************************************************************/
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#include "platform.h"
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#include <libmaxsi/memory.h>
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#include "multiboot.h"
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#include "panic.h"
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#include "../memorymanagement.h"
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#include "x86-family/memorymanagement.h"
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namespace Sortix
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{
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namespace Page
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{
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extern size_t stackused;
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extern size_t stacklength;
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}
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namespace Memory
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{
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extern addr_t currentdir;
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void InitCPU()
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{
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PML* const BOOTPML2 = (PML* const) 0x01000UL;
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PML* const BOOTPML1 = (PML* const) 0x02000UL;
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PML* const FORKPML1 = (PML* const) 0x03000UL;
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PML* const IDENPML1 = (PML* const) 0x04000UL;
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// Initialize the memory structures with zeroes.
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Maxsi::Memory::Set(BOOTPML1, 0, 0x6000UL);
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// Identity map the first 4 MiB.
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addr_t flags = PML_PRESENT | PML_WRITABLE;
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BOOTPML2->entry[0] = ((addr_t) IDENPML1) | flags;
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for ( size_t i = 0; i < ENTRIES; i++ )
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{
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IDENPML1->entry[i] = (i * 4096UL) | flags;
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}
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// Next order of business is to map the virtual memory structures
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// to the pre-defined locations in the virtual address space.
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// Fractal map the PML1s.
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BOOTPML2->entry[1023] = (addr_t) BOOTPML2 | flags;
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// Fractal map the PML2s.
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BOOTPML2->entry[1022] = (addr_t) BOOTPML1 | flags | PML_FORK;
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BOOTPML1->entry[1023] = (addr_t) BOOTPML2 | flags;
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// Add some predefined room for forking address spaces.
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BOOTPML1->entry[0] = (addr_t) FORKPML1 | flags | PML_FORK;
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// The virtual memory structures are now available on the predefined
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// locations. This means the virtual memory code is bootstrapped. Of
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// course, we still have no physical page allocator, so that's the
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// next step.
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PML* const PHYSPML1 = (PML* const) 0x05000UL;
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PML* const PHYSPML0 = (PML* const) 0x06000UL;
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BOOTPML2->entry[1021] = (addr_t) PHYSPML1 | flags;
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PHYSPML1->entry[0] = (addr_t) PHYSPML0 | flags;
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// Alright, enable virtual memory!
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SwitchAddressSpace((addr_t) BOOTPML2);
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size_t cr0;
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asm volatile("mov %%cr0, %0": "=r"(cr0));
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cr0 |= 0x80000000UL; /* Enable paging! */
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asm volatile("mov %0, %%cr0":: "r"(cr0));
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Page::stackused = 0;
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Page::stacklength = 4096UL / sizeof(addr_t);
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// The physical memory allocator should now be ready for use. Next
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// up, the calling function will fill up the physical allocator with
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// plenty of nice physical pages. (see Page::InitPushRegion)
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}
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}
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}
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