Also got rid of trailing white space. That corrupted .git/. Big ass-commit because of recovered .git directory.
201 lines
6 KiB
C++
201 lines
6 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 <sortix/kernel/platform.h>
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#include <libmaxsi/memory.h>
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#include "multiboot.h"
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#include <sortix/kernel/panic.h>
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#include <sortix/kernel/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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void ExtendStack();
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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((PML* const) 0x01000UL, 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] = 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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// Please note that even if this function exists, you should still clean
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// up the address space of a process _before_ calling
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// DestroyAddressSpace. This is just a hack because it currently is
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// impossible to clean up PLM1's using the MM api!
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// ---
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// TODO: This function is duplicated in {x86,x64}/memorymanagement.cpp!
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// ---
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void RecursiveFreeUserspacePages(size_t level, size_t offset)
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{
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PML* pml = PMLS[level] + offset;
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for ( size_t i = 0; i < ENTRIES; i++ )
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{
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if ( !(pml->entry[i] & PML_PRESENT) ) { continue; }
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if ( !(pml->entry[i] & PML_USERSPACE) ) { continue; }
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if ( !(pml->entry[i] & PML_FORK) ) { continue; }
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if ( level > 1 ) { RecursiveFreeUserspacePages(level-1, offset * ENTRIES + i); }
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addr_t addr = pml->entry[i] & PML_ADDRESS;
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pml->entry[i] = 0;
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Page::Put(addr);
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}
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}
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void DestroyAddressSpace()
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{
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// First let's do the safe part. Garbage collect any PML1/0's left
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// behind by user-space. These are completely safe to delete.
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RecursiveFreeUserspacePages(TOPPMLLEVEL, 0);
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// Let's destroy the current address space! Oh wait. If we do that,
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// hell will break loose half-way when we start unmapping this piece
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// of code.
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// Instead, let's just mark the relevant pages as unused and switch
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// to another address space as fast as humanely possible. Any memory
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// allocation could potentially modify the current paging structures
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// and overwrite their contents causing a tripple-fault!
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// Make sure Page::Put does NOT cause any Page::Get's internally!
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const size_t NUM_PAGES = 2;
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size_t pagestackfree = Page::stacklength - Page::stackused;
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if ( pagestackfree < NUM_PAGES ) { Page::ExtendStack(); }
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addr_t fractal1 = PMLS[2]->entry[1022];
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Page::Put(fractal1 & PML_ADDRESS);
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Page::Put(currentdir & PML_ADDRESS);
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// Switch to the address space from when the world was originally
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// created. It should contain the kernel, the whole kernel, and
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// nothing but the kernel.
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PML* const BOOTPML2 = (PML* const) 0x01000UL;
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SwitchAddressSpace((addr_t) BOOTPML2);
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}
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const size_t KERNEL_STACK_SIZE = 256UL * 1024UL;
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const addr_t KERNEL_STACK_END = 0x80001000UL;
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const addr_t KERNEL_STACK_START = KERNEL_STACK_END + KERNEL_STACK_SIZE;
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addr_t INITRD = KERNEL_STACK_START;
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size_t initrdsize = 0;
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const addr_t HEAPUPPER = 0xFF400000UL;
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addr_t GetInitRD()
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{
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return INITRD;
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}
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size_t GetInitRDSize()
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{
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return initrdsize;
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}
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void RegisterInitRDSize(size_t size)
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{
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initrdsize = size;
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}
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addr_t GetHeapLower()
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{
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return Page::AlignUp(INITRD + initrdsize);
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}
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addr_t GetHeapUpper()
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{
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return HEAPUPPER;
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}
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addr_t GetKernelStack()
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{
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return KERNEL_STACK_START;
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}
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size_t GetKernelStackSize()
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{
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return KERNEL_STACK_SIZE;
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}
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}
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}
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