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/*
* Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
* Copyright (c) 2018-2022, James Mintram <me@jamesrm.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Singleton.h>
#include <Kernel/Arch/CPU.h>
#include <Kernel/Arch/PageDirectory.h>
#include <Kernel/Arch/aarch64/ASM_wrapper.h>
#include <Kernel/InterruptDisabler.h>
#include <Kernel/Memory/MemoryManager.h>
#include <Kernel/Prekernel/Prekernel.h>
#include <Kernel/Process.h>
#include <Kernel/Random.h>
#include <Kernel/Sections.h>
#include <Kernel/Thread.h>
namespace Kernel::Memory {
struct TTBR0Map {
SpinlockProtected<IntrusiveRedBlackTree<&PageDirectory::m_tree_node>, LockRank::None> map {};
};
static Singleton<TTBR0Map> s_ttbr0_map;
void PageDirectory::register_page_directory(PageDirectory* directory)
{
s_ttbr0_map->map.with([&](auto& map) {
map.insert(directory->ttbr0(), *directory);
});
}
void PageDirectory::deregister_page_directory(PageDirectory* directory)
{
s_ttbr0_map->map.with([&](auto& map) {
map.remove(directory->ttbr0());
});
}
LockRefPtr<PageDirectory> PageDirectory::find_current()
{
return s_ttbr0_map->map.with([&](auto& map) {
return map.find(Aarch64::Asm::get_ttbr0_el1());
});
}
void activate_kernel_page_directory(PageDirectory const& page_directory)
{
Aarch64::Asm::set_ttbr0_el1(page_directory.ttbr0());
}
void activate_page_directory(PageDirectory const& page_directory, Thread* current_thread)
{
current_thread->regs().ttbr0_el1 = page_directory.ttbr0();
Aarch64::Asm::set_ttbr0_el1(page_directory.ttbr0());
}
UNMAP_AFTER_INIT NonnullLockRefPtr<PageDirectory> PageDirectory::must_create_kernel_page_directory()
{
return adopt_lock_ref_if_nonnull(new (nothrow) PageDirectory).release_nonnull();
}
ErrorOr<NonnullLockRefPtr<PageDirectory>> PageDirectory::try_create_for_userspace()
{
auto directory = TRY(adopt_nonnull_lock_ref_or_enomem(new (nothrow) PageDirectory));
directory->m_root_table = TRY(MM.allocate_physical_page());
directory->m_directory_table = TRY(MM.allocate_physical_page());
auto kernel_pd_index = (kernel_mapping_base >> 30) & 0x1ffu;
for (size_t i = 0; i < kernel_pd_index; i++) {
directory->m_directory_pages[i] = TRY(MM.allocate_physical_page());
}
// Share the top 1 GiB of kernel-only mappings (>=kernel_mapping_base)
directory->m_directory_pages[kernel_pd_index] = MM.kernel_page_directory().m_directory_pages[kernel_pd_index];
{
InterruptDisabler disabler;
auto& table = *(PageDirectoryPointerTable*)MM.quickmap_page(*directory->m_root_table);
table.raw[0] = (FlatPtr)directory->m_directory_table->paddr().as_ptr() | TABLE_DESCRIPTOR;
MM.unquickmap_page();
}
{
InterruptDisabler disabler;
auto& table = *(PageDirectoryPointerTable*)MM.quickmap_page(*directory->m_directory_table);
for (size_t i = 0; i < sizeof(m_directory_pages) / sizeof(m_directory_pages[0]); i++) {
if (directory->m_directory_pages[i]) {
table.raw[i] = (FlatPtr)directory->m_directory_pages[i]->paddr().as_ptr() | PAGE_DESCRIPTOR;
}
}
MM.unquickmap_page();
}
register_page_directory(directory);
return directory;
}
PageDirectory::PageDirectory() = default;
UNMAP_AFTER_INIT void PageDirectory::allocate_kernel_directory()
{
// Adopt the page tables already set up by boot.S
dmesgln("MM: boot_pml4t @ {}", boot_pml4t);
m_root_table = PhysicalPage::create(boot_pml4t, MayReturnToFreeList::No);
dmesgln("MM: boot_pdpt @ {}", boot_pdpt);
dmesgln("MM: boot_pd0 @ {}", boot_pd0);
dmesgln("MM: boot_pd_kernel @ {}", boot_pd_kernel);
m_directory_table = PhysicalPage::create(boot_pdpt, MayReturnToFreeList::No);
m_directory_pages[0] = PhysicalPage::create(boot_pd0, MayReturnToFreeList::No);
m_directory_pages[(kernel_mapping_base >> 30) & 0x1ff] = PhysicalPage::create(boot_pd_kernel, MayReturnToFreeList::No);
}
PageDirectory::~PageDirectory()
{
if (is_root_table_initialized()) {
deregister_page_directory(this);
}
}
}
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