ladybird/Kernel/VM/PageDirectory.cpp
Tom 655f4daeb1 Kernel: Minor MM optimization for SMP
MemoryManager::quickmap_pd and MemoryManager::quickmap_pt can only
be called by one processor at the time anyway, since anything using
these must have the MM lock held. So, no need to inform the other
CPUs to flush their TLBs, we can just flush our own.
2020-07-06 17:17:24 +02:00

124 lines
5 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT HOLDER OR CONTRIBUTORS 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 <AK/Memory.h>
#include <Kernel/Process.h>
#include <Kernel/Random.h>
#include <Kernel/Thread.h>
#include <Kernel/VM/MemoryManager.h>
#include <Kernel/VM/PageDirectory.h>
namespace Kernel {
static const FlatPtr userspace_range_base = 0x00800000;
static const FlatPtr userspace_range_ceiling = 0xbe000000;
static const FlatPtr kernelspace_range_base = 0xc0800000;
static HashMap<u32, PageDirectory*>& cr3_map()
{
ASSERT_INTERRUPTS_DISABLED();
static HashMap<u32, PageDirectory*>* map;
if (!map)
map = new HashMap<u32, PageDirectory*>;
return *map;
}
RefPtr<PageDirectory> PageDirectory::find_by_cr3(u32 cr3)
{
ScopedSpinLock lock(s_mm_lock);
return cr3_map().get(cr3).value_or({});
}
extern "C" PageDirectoryEntry* boot_pdpt[4];
extern "C" PageDirectoryEntry boot_pd0[1024];
extern "C" PageDirectoryEntry boot_pd3[1024];
PageDirectory::PageDirectory()
{
m_range_allocator.initialize_with_range(VirtualAddress(0xc0800000), 0x3f000000);
m_identity_range_allocator.initialize_with_range(VirtualAddress(FlatPtr(0x00000000)), 0x00200000);
// Adopt the page tables already set up by boot.S
PhysicalAddress boot_pdpt_paddr(virtual_to_low_physical((FlatPtr)boot_pdpt));
PhysicalAddress boot_pd0_paddr(virtual_to_low_physical((FlatPtr)boot_pd0));
PhysicalAddress boot_pd3_paddr(virtual_to_low_physical((FlatPtr)boot_pd3));
klog() << "MM: boot_pdpt @ " << boot_pdpt_paddr;
klog() << "MM: boot_pd0 @ " << boot_pd0_paddr;
klog() << "MM: boot_pd3 @ " << boot_pd3_paddr;
m_directory_table = PhysicalPage::create(boot_pdpt_paddr, true, false);
m_directory_pages[0] = PhysicalPage::create(boot_pd0_paddr, true, false);
m_directory_pages[3] = PhysicalPage::create(boot_pd3_paddr, true, false);
}
PageDirectory::PageDirectory(Process& process, const RangeAllocator* parent_range_allocator)
: m_process(&process)
{
ScopedSpinLock lock(s_mm_lock);
if (parent_range_allocator) {
m_range_allocator.initialize_from_parent(*parent_range_allocator);
} else {
size_t random_offset = (get_fast_random<u32>() % 32 * MB) & PAGE_MASK;
u32 base = userspace_range_base + random_offset;
m_range_allocator.initialize_with_range(VirtualAddress(base), userspace_range_ceiling - base);
}
// Set up a userspace page directory
m_directory_table = MM.allocate_user_physical_page();
m_directory_pages[0] = MM.allocate_user_physical_page();
m_directory_pages[1] = MM.allocate_user_physical_page();
m_directory_pages[2] = MM.allocate_user_physical_page();
// Share the top 1 GB of kernel-only mappings (>=3GB or >=0xc0000000)
m_directory_pages[3] = MM.kernel_page_directory().m_directory_pages[3];
{
auto& table = *(PageDirectoryPointerTable*)MM.quickmap_page(*m_directory_table);
table.raw[0] = (u64)m_directory_pages[0]->paddr().as_ptr() | 1;
table.raw[1] = (u64)m_directory_pages[1]->paddr().as_ptr() | 1;
table.raw[2] = (u64)m_directory_pages[2]->paddr().as_ptr() | 1;
table.raw[3] = (u64)m_directory_pages[3]->paddr().as_ptr() | 1;
MM.unquickmap_page();
}
// Clone bottom 2 MB of mappings from kernel_page_directory
PageDirectoryEntry buffer;
auto* kernel_pd = MM.quickmap_pd(MM.kernel_page_directory(), 0);
memcpy(&buffer, kernel_pd, sizeof(PageDirectoryEntry));
auto* new_pd = MM.quickmap_pd(*this, 0);
memcpy(new_pd, &buffer, sizeof(PageDirectoryEntry));
cr3_map().set(cr3(), this);
}
PageDirectory::~PageDirectory()
{
#ifdef MM_DEBUG
dbg() << "MM: ~PageDirectory K" << this;
#endif
ScopedSpinLock lock(s_mm_lock);
cr3_map().remove(cr3());
}
}