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a246e9cd7e
uintptr_t is 32-bit or 64-bit depending on the target platform. This will help us write pointer size agnostic code so that when the day comes that we want to do a 64-bit port, we'll be in better shape.
120 lines
4.9 KiB
C++
120 lines
4.9 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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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 are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <Kernel/Process.h>
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#include <Kernel/Random.h>
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#include <Kernel/Thread.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/PageDirectory.h>
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static const uintptr_t userspace_range_base = 0x00800000;
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static const uintptr_t userspace_range_ceiling = 0xbe000000;
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static const uintptr_t kernelspace_range_base = 0xc0800000;
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static HashMap<u32, PageDirectory*>& cr3_map()
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{
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ASSERT_INTERRUPTS_DISABLED();
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static HashMap<u32, PageDirectory*>* map;
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if (!map)
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map = new HashMap<u32, PageDirectory*>;
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return *map;
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}
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RefPtr<PageDirectory> PageDirectory::find_by_cr3(u32 cr3)
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{
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InterruptDisabler disabler;
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return cr3_map().get(cr3).value_or({});
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}
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extern "C" PageDirectoryEntry* boot_pdpt[4];
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extern "C" PageDirectoryEntry boot_pd0[1024];
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extern "C" PageDirectoryEntry boot_pd3[1024];
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PageDirectory::PageDirectory()
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{
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m_range_allocator.initialize_with_range(VirtualAddress(0xc0800000), 0x3f000000);
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// Adopt the page tables already set up by boot.S
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PhysicalAddress boot_pdpt_paddr(virtual_to_low_physical((uintptr_t)boot_pdpt));
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PhysicalAddress boot_pd0_paddr(virtual_to_low_physical((uintptr_t)boot_pd0));
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PhysicalAddress boot_pd3_paddr(virtual_to_low_physical((uintptr_t)boot_pd3));
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kprintf("MM: boot_pdpt @ P%p\n", boot_pdpt_paddr.get());
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kprintf("MM: boot_pd0 @ P%p\n", boot_pd0_paddr.get());
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kprintf("MM: boot_pd3 @ P%p\n", boot_pd3_paddr.get());
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m_directory_table = PhysicalPage::create(boot_pdpt_paddr, true, false);
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m_directory_pages[0] = PhysicalPage::create(boot_pd0_paddr, true, false);
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m_directory_pages[3] = PhysicalPage::create(boot_pd3_paddr, true, false);
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}
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PageDirectory::PageDirectory(Process& process, const RangeAllocator* parent_range_allocator)
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: m_process(&process)
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{
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if (parent_range_allocator) {
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m_range_allocator.initialize_from_parent(*parent_range_allocator);
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} else {
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size_t random_offset = (get_good_random<u32>() % 32 * MB) & PAGE_MASK;
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u32 base = userspace_range_base + random_offset;
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m_range_allocator.initialize_with_range(VirtualAddress(base), userspace_range_ceiling - base);
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}
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// Set up a userspace page directory
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m_directory_table = MM.allocate_user_physical_page();
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m_directory_pages[0] = MM.allocate_user_physical_page();
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m_directory_pages[1] = MM.allocate_user_physical_page();
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m_directory_pages[2] = MM.allocate_user_physical_page();
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// Share the top 1 GB of kernel-only mappings (>=3GB or >=0xc0000000)
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m_directory_pages[3] = MM.kernel_page_directory().m_directory_pages[3];
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{
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InterruptDisabler disabler;
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auto& table = *(PageDirectoryPointerTable*)MM.quickmap_page(*m_directory_table);
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table.raw[0] = (u64)m_directory_pages[0]->paddr().as_ptr() | 1;
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table.raw[1] = (u64)m_directory_pages[1]->paddr().as_ptr() | 1;
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table.raw[2] = (u64)m_directory_pages[2]->paddr().as_ptr() | 1;
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table.raw[3] = (u64)m_directory_pages[3]->paddr().as_ptr() | 1;
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MM.unquickmap_page();
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}
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// Clone bottom 2 MB of mappings from kernel_page_directory
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PageDirectoryEntry buffer;
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auto* kernel_pd = MM.quickmap_pd(MM.kernel_page_directory(), 0);
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memcpy(&buffer, kernel_pd, sizeof(PageDirectoryEntry));
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auto* new_pd = MM.quickmap_pd(*this, 0);
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memcpy(new_pd, &buffer, sizeof(PageDirectoryEntry));
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InterruptDisabler disabler;
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cr3_map().set(cr3(), this);
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}
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PageDirectory::~PageDirectory()
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{
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#ifdef MM_DEBUG
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dbgprintf("MM: ~PageDirectory K%x\n", this);
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#endif
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InterruptDisabler disabler;
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cr3_map().remove(cr3());
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}
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