126 lines
4.2 KiB
C++
126 lines
4.2 KiB
C++
/*
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* Copyright (c) 2011, 2012, 2014, 2015 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* x64/memorymanagement.cpp
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* Handles memory for the x64 architecture.
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*/
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#include <string.h>
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#include <sortix/kernel/interrupt.h>
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#include <sortix/kernel/kernel.h>
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#include <sortix/kernel/memorymanagement.h>
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#include "multiboot.h"
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#include "x86-family/memorymanagement.h"
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namespace Sortix {
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namespace Memory {
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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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addr_t entry = pml->entry[i];
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if ( !(entry & PML_PRESENT) )
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continue;
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if ( !(entry & PML_USERSPACE) )
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continue;
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if ( !(entry & PML_FORK) )
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continue;
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if ( 1 < level )
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RecursiveFreeUserspacePages(level-1, offset * ENTRIES + i);
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addr_t addr = pml->entry[i] & PML_ADDRESS;
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// No need to unmap the page, we just need to mark it as unused.
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Page::PutUnlocked(addr, PAGE_USAGE_PAGING_OVERHEAD);
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}
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}
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void DestroyAddressSpace(addr_t fallback)
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{
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// Look up the last few entries used for the fractal mapping. These
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// cannot be unmapped as that would destroy the world. Instead, we
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// will remember them, switch to another adress space, and safely
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// mark them as unused. Also handling the forking related pages.
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addr_t fractal3 = (PMLS[4] + 0)->entry[510UL];
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addr_t fork2 = (PMLS[3] + 510UL)->entry[0];
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addr_t fractal2 = (PMLS[3] + 510UL)->entry[510];
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addr_t fork1 = (PMLS[2] + 510UL * 512UL + 0)->entry[0];
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addr_t fractal1 = (PMLS[2] + 510UL * 512UL + 510UL)->entry[510];
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addr_t dir = GetAddressSpace();
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// We want to free the pages, but we are still using them ourselves,
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// so lock the page allocation structure until we are done.
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Page::Lock();
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// In case any pages wasn't cleaned at this point.
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// TODO: Page::Put calls may internally Page::Get and then reusing pages we are not done with just yet
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RecursiveFreeUserspacePages(TOPPMLLEVEL, 0);
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SwitchAddressSpace(fallback);
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// Ok, now we got marked everything left behind as unused, we can
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// now safely let another thread use the pages.
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Page::Unlock();
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// These are safe to free since we switched address space.
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Page::Put(fractal3 & PML_ADDRESS, PAGE_USAGE_PAGING_OVERHEAD);
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Page::Put(fractal2 & PML_ADDRESS, PAGE_USAGE_PAGING_OVERHEAD);
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Page::Put(fractal1 & PML_ADDRESS, PAGE_USAGE_PAGING_OVERHEAD);
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Page::Put(fork2 & PML_ADDRESS, PAGE_USAGE_PAGING_OVERHEAD);
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Page::Put(fork1 & PML_ADDRESS, PAGE_USAGE_PAGING_OVERHEAD);
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Page::Put(dir & PML_ADDRESS, PAGE_USAGE_PAGING_OVERHEAD);
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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 = 0xFFFF800000001000UL;
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const addr_t KERNEL_STACK_START = KERNEL_STACK_END + KERNEL_STACK_SIZE;
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const addr_t VIRTUAL_AREA_LOWER = KERNEL_STACK_START;
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const addr_t VIRTUAL_AREA_UPPER = 0xFFFFFE8000000000UL;
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void GetKernelVirtualArea(addr_t* from, size_t* size)
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{
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*from = KERNEL_STACK_END;
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*size = VIRTUAL_AREA_UPPER - VIRTUAL_AREA_LOWER;
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}
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void GetUserVirtualArea(uintptr_t* from, size_t* size)
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{
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*from = 0x400000; // 4 MiB.
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*size = 0x800000000000 - *from; // 128 TiB - 4 MiB.
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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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} // namespace Memory
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} // namespace Sortix
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