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ladybird/Kernel/Memory/MemoryManager.cpp
Idan Horowitz 12300b7d0b Kernel: Dump OOM debug info after releasing the MM global data lock 
Otherwise we would be holding the MM global data lock and the Process
address space locks in reversed order to the rest of the system, which
can lead to deadlocks.
2022-08-27 21:54:13 +03:00

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/*
* Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/Assertions.h>
#include <AK/Memory.h>
#include <AK/NonnullRefPtrVector.h>
#include <AK/StringView.h>
#include <Kernel/Arch/CPU.h>
#include <Kernel/Arch/InterruptDisabler.h>
#include <Kernel/Arch/PageDirectory.h>
#include <Kernel/Arch/PageFault.h>
#include <Kernel/Arch/RegisterState.h>
#include <Kernel/BootInfo.h>
#include <Kernel/CMOS.h>
#include <Kernel/FileSystem/Inode.h>
#include <Kernel/Heap/kmalloc.h>
#include <Kernel/KSyms.h>
#include <Kernel/Memory/AnonymousVMObject.h>
#include <Kernel/Memory/MemoryManager.h>
#include <Kernel/Memory/PageDirectory.h>
#include <Kernel/Memory/PhysicalRegion.h>
#include <Kernel/Memory/SharedInodeVMObject.h>
#include <Kernel/Multiboot.h>
#include <Kernel/Panic.h>
#include <Kernel/Prekernel/Prekernel.h>
#include <Kernel/Process.h>
#include <Kernel/Sections.h>
#include <Kernel/StdLib.h>
extern u8 start_of_kernel_image[];
extern u8 end_of_kernel_image[];
extern u8 start_of_kernel_text[];
extern u8 start_of_kernel_data[];
extern u8 end_of_kernel_bss[];
extern u8 start_of_ro_after_init[];
extern u8 end_of_ro_after_init[];
extern u8 start_of_unmap_after_init[];
extern u8 end_of_unmap_after_init[];
extern u8 start_of_kernel_ksyms[];
extern u8 end_of_kernel_ksyms[];
extern multiboot_module_entry_t multiboot_copy_boot_modules_array[16];
extern size_t multiboot_copy_boot_modules_count;
namespace Kernel::Memory {
ErrorOr<FlatPtr> page_round_up(FlatPtr x)
{
if (x > (explode_byte(0xFF) & ~0xFFF)) {
return Error::from_errno(EINVAL);
}
return (((FlatPtr)(x)) + PAGE_SIZE - 1) & (~(PAGE_SIZE - 1));
}
// NOTE: We can NOT use Singleton for this class, because
// MemoryManager::initialize is called *before* global constructors are
// run. If we do, then Singleton would get re-initialized, causing
// the memory manager to be initialized twice!
static MemoryManager* s_the;
MemoryManager& MemoryManager::the()
{
return *s_the;
}
bool MemoryManager::is_initialized()
{
return s_the != nullptr;
}
static UNMAP_AFTER_INIT VirtualRange kernel_virtual_range()
{
size_t kernel_range_start = kernel_mapping_base + 2 * MiB; // The first 2 MiB are used for mapping the pre-kernel
return VirtualRange { VirtualAddress(kernel_range_start), KERNEL_PD_END - kernel_range_start };
}
MemoryManager::GlobalData::GlobalData()
: region_tree(kernel_virtual_range())
{
}
UNMAP_AFTER_INIT MemoryManager::MemoryManager()
: m_global_data(LockRank::None)
{
s_the = this;
parse_memory_map();
activate_kernel_page_directory(kernel_page_directory());
protect_kernel_image();
// We're temporarily "committing" to two pages that we need to allocate below
auto committed_pages = commit_physical_pages(2).release_value();
m_shared_zero_page = committed_pages.take_one();
// We're wasting a page here, we just need a special tag (physical
// address) so that we know when we need to lazily allocate a page
// that we should be drawing this page from the committed pool rather
// than potentially failing if no pages are available anymore.
// By using a tag we don't have to query the VMObject for every page
// whether it was committed or not
m_lazy_committed_page = committed_pages.take_one();
}
UNMAP_AFTER_INIT MemoryManager::~MemoryManager() = default;
UNMAP_AFTER_INIT void MemoryManager::protect_kernel_image()
{
SpinlockLocker page_lock(kernel_page_directory().get_lock());
// Disable writing to the kernel text and rodata segments.
for (auto const* i = start_of_kernel_text; i < start_of_kernel_data; i += PAGE_SIZE) {
auto& pte = *ensure_pte(kernel_page_directory(), VirtualAddress(i));
pte.set_writable(false);
}
if (Processor::current().has_nx()) {
// Disable execution of the kernel data, bss and heap segments.
for (auto const* i = start_of_kernel_data; i < end_of_kernel_image; i += PAGE_SIZE) {
auto& pte = *ensure_pte(kernel_page_directory(), VirtualAddress(i));
pte.set_execute_disabled(true);
}
}
}
UNMAP_AFTER_INIT void MemoryManager::unmap_prekernel()
{
SpinlockLocker page_lock(kernel_page_directory().get_lock());
auto start = start_of_prekernel_image.page_base().get();
auto end = end_of_prekernel_image.page_base().get();
for (auto i = start; i <= end; i += PAGE_SIZE)
release_pte(kernel_page_directory(), VirtualAddress(i), i == end ? IsLastPTERelease::Yes : IsLastPTERelease::No);
flush_tlb(&kernel_page_directory(), VirtualAddress(start), (end - start) / PAGE_SIZE);
}
UNMAP_AFTER_INIT void MemoryManager::protect_readonly_after_init_memory()
{
SpinlockLocker page_lock(kernel_page_directory().get_lock());
// Disable writing to the .ro_after_init section
for (auto i = (FlatPtr)&start_of_ro_after_init; i < (FlatPtr)&end_of_ro_after_init; i += PAGE_SIZE) {
auto& pte = *ensure_pte(kernel_page_directory(), VirtualAddress(i));
pte.set_writable(false);
flush_tlb(&kernel_page_directory(), VirtualAddress(i));
}
}
void MemoryManager::unmap_text_after_init()
{
SpinlockLocker page_lock(kernel_page_directory().get_lock());
auto start = page_round_down((FlatPtr)&start_of_unmap_after_init);
auto end = page_round_up((FlatPtr)&end_of_unmap_after_init).release_value_but_fixme_should_propagate_errors();
// Unmap the entire .unmap_after_init section
for (auto i = start; i < end; i += PAGE_SIZE) {
auto& pte = *ensure_pte(kernel_page_directory(), VirtualAddress(i));
pte.clear();
flush_tlb(&kernel_page_directory(), VirtualAddress(i));
}
dmesgln("Unmapped {} KiB of kernel text after init! :^)", (end - start) / KiB);
}
UNMAP_AFTER_INIT void MemoryManager::protect_ksyms_after_init()
{
SpinlockLocker page_lock(kernel_page_directory().get_lock());
auto start = page_round_down((FlatPtr)start_of_kernel_ksyms);
auto end = page_round_up((FlatPtr)end_of_kernel_ksyms).release_value_but_fixme_should_propagate_errors();
for (auto i = start; i < end; i += PAGE_SIZE) {
auto& pte = *ensure_pte(kernel_page_directory(), VirtualAddress(i));
pte.set_writable(false);
flush_tlb(&kernel_page_directory(), VirtualAddress(i));
}
dmesgln("Write-protected kernel symbols after init.");
}
IterationDecision MemoryManager::for_each_physical_memory_range(Function<IterationDecision(PhysicalMemoryRange const&)> callback)
{
return m_global_data.with([&](auto& global_data) {
VERIFY(!global_data.physical_memory_ranges.is_empty());
for (auto& current_range : global_data.physical_memory_ranges) {
IterationDecision decision = callback(current_range);
if (decision != IterationDecision::Continue)
return decision;
}
return IterationDecision::Continue;
});
}
UNMAP_AFTER_INIT void MemoryManager::register_reserved_ranges()
{
m_global_data.with([&](auto& global_data) {
VERIFY(!global_data.physical_memory_ranges.is_empty());
ContiguousReservedMemoryRange range;
for (auto& current_range : global_data.physical_memory_ranges) {
if (current_range.type != PhysicalMemoryRangeType::Reserved) {
if (range.start.is_null())
continue;
global_data.reserved_memory_ranges.append(ContiguousReservedMemoryRange { range.start, current_range.start.get() - range.start.get() });
range.start.set((FlatPtr) nullptr);
continue;
}
if (!range.start.is_null()) {
continue;
}
range.start = current_range.start;
}
if (global_data.physical_memory_ranges.last().type != PhysicalMemoryRangeType::Reserved)
return;
if (range.start.is_null())
return;
global_data.reserved_memory_ranges.append(ContiguousReservedMemoryRange { range.start, global_data.physical_memory_ranges.last().start.get() + global_data.physical_memory_ranges.last().length - range.start.get() });
});
}
bool MemoryManager::is_allowed_to_read_physical_memory_for_userspace(PhysicalAddress start_address, size_t read_length) const
{
// Note: Guard against overflow in case someone tries to mmap on the edge of
// the RAM
if (start_address.offset_addition_would_overflow(read_length))
return false;
auto end_address = start_address.offset(read_length);
return m_global_data.with([&](auto& global_data) {
for (auto const& current_range : global_data.reserved_memory_ranges) {
if (current_range.start > start_address)
continue;
if (current_range.start.offset(current_range.length) < end_address)
continue;
return true;
}
return false;
});
}
UNMAP_AFTER_INIT void MemoryManager::parse_memory_map()
{
// Register used memory regions that we know of.
m_global_data.with([&](auto& global_data) {
global_data.used_memory_ranges.ensure_capacity(4);
global_data.used_memory_ranges.append(UsedMemoryRange { UsedMemoryRangeType::LowMemory, PhysicalAddress(0x00000000), PhysicalAddress(1 * MiB) });
global_data.used_memory_ranges.append(UsedMemoryRange { UsedMemoryRangeType::Kernel, PhysicalAddress(virtual_to_low_physical((FlatPtr)start_of_kernel_image)), PhysicalAddress(page_round_up(virtual_to_low_physical((FlatPtr)end_of_kernel_image)).release_value_but_fixme_should_propagate_errors()) });
if (multiboot_flags & 0x4) {
auto* bootmods_start = multiboot_copy_boot_modules_array;
auto* bootmods_end = bootmods_start + multiboot_copy_boot_modules_count;
for (auto* bootmod = bootmods_start; bootmod < bootmods_end; bootmod++) {
global_data.used_memory_ranges.append(UsedMemoryRange { UsedMemoryRangeType::BootModule, PhysicalAddress(bootmod->start), PhysicalAddress(bootmod->end) });
}
}
auto* mmap_begin = multiboot_memory_map;
auto* mmap_end = multiboot_memory_map + multiboot_memory_map_count;
struct ContiguousPhysicalVirtualRange {
PhysicalAddress lower;
PhysicalAddress upper;
};
Vector<ContiguousPhysicalVirtualRange> contiguous_physical_ranges;
for (auto* mmap = mmap_begin; mmap < mmap_end; mmap++) {
// We have to copy these onto the stack, because we take a reference to these when printing them out,
// and doing so on a packed struct field is UB.
auto address = mmap->addr;
auto length = mmap->len;
ArmedScopeGuard write_back_guard = [&]() {
mmap->addr = address;
mmap->len = length;
};
dmesgln("MM: Multiboot mmap: address={:p}, length={}, type={}", address, length, mmap->type);
auto start_address = PhysicalAddress(address);
switch (mmap->type) {
case (MULTIBOOT_MEMORY_AVAILABLE):
global_data.physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::Usable, start_address, length });
break;
case (MULTIBOOT_MEMORY_RESERVED):
global_data.physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::Reserved, start_address, length });
break;
case (MULTIBOOT_MEMORY_ACPI_RECLAIMABLE):
global_data.physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::ACPI_Reclaimable, start_address, length });
break;
case (MULTIBOOT_MEMORY_NVS):
global_data.physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::ACPI_NVS, start_address, length });
break;
case (MULTIBOOT_MEMORY_BADRAM):
dmesgln("MM: Warning, detected bad memory range!");
global_data.physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::BadMemory, start_address, length });
break;
default:
dbgln("MM: Unknown range!");
global_data.physical_memory_ranges.append(PhysicalMemoryRange { PhysicalMemoryRangeType::Unknown, start_address, length });
break;
}
if (mmap->type != MULTIBOOT_MEMORY_AVAILABLE)
continue;
// Fix up unaligned memory regions.
auto diff = (FlatPtr)address % PAGE_SIZE;
if (diff != 0) {
dmesgln("MM: Got an unaligned physical_region from the bootloader; correcting {:p} by {} bytes", address, diff);
diff = PAGE_SIZE - diff;
address += diff;
length -= diff;
}
if ((length % PAGE_SIZE) != 0) {
dmesgln("MM: Got an unaligned physical_region from the bootloader; correcting length {} by {} bytes", length, length % PAGE_SIZE);
length -= length % PAGE_SIZE;
}
if (length < PAGE_SIZE) {
dmesgln("MM: Memory physical_region from bootloader is too small; we want >= {} bytes, but got {} bytes", PAGE_SIZE, length);
continue;
}
for (PhysicalSize page_base = address; page_base <= (address + length); page_base += PAGE_SIZE) {
auto addr = PhysicalAddress(page_base);
// Skip used memory ranges.
bool should_skip = false;
for (auto& used_range : global_data.used_memory_ranges) {
if (addr.get() >= used_range.start.get() && addr.get() <= used_range.end.get()) {
should_skip = true;
break;
}
}
if (should_skip)
continue;
if (contiguous_physical_ranges.is_empty() || contiguous_physical_ranges.last().upper.offset(PAGE_SIZE) != addr) {
contiguous_physical_ranges.append(ContiguousPhysicalVirtualRange {
.lower = addr,
.upper = addr,
});
} else {
contiguous_physical_ranges.last().upper = addr;
}
}
}
for (auto& range : contiguous_physical_ranges) {
global_data.physical_regions.append(PhysicalRegion::try_create(range.lower, range.upper).release_nonnull());
}
for (auto& region : global_data.physical_regions)
global_data.system_memory_info.physical_pages += region.size();
register_reserved_ranges();
for (auto& range : global_data.reserved_memory_ranges) {
dmesgln("MM: Contiguous reserved range from {}, length is {}", range.start, range.length);
}
initialize_physical_pages();
VERIFY(global_data.system_memory_info.physical_pages > 0);
// We start out with no committed pages
global_data.system_memory_info.physical_pages_uncommitted = global_data.system_memory_info.physical_pages;
for (auto& used_range : global_data.used_memory_ranges) {
dmesgln("MM: {} range @ {} - {} (size {:#x})", UserMemoryRangeTypeNames[to_underlying(used_range.type)], used_range.start, used_range.end.offset(-1), used_range.end.as_ptr() - used_range.start.as_ptr());
}
for (auto& region : global_data.physical_regions) {
dmesgln("MM: User physical region: {} - {} (size {:#x})", region.lower(), region.upper().offset(-1), PAGE_SIZE * region.size());
region.initialize_zones();
}
});
}
UNMAP_AFTER_INIT void MemoryManager::initialize_physical_pages()
{
m_global_data.with([&](auto& global_data) {
// We assume that the physical page range is contiguous and doesn't contain huge gaps!
PhysicalAddress highest_physical_address;
for (auto& range : global_data.used_memory_ranges) {
if (range.end.get() > highest_physical_address.get())
highest_physical_address = range.end;
}
for (auto& region : global_data.physical_memory_ranges) {
auto range_end = PhysicalAddress(region.start).offset(region.length);
if (range_end.get() > highest_physical_address.get())
highest_physical_address = range_end;
}
// Calculate how many total physical pages the array will have
m_physical_page_entries_count = PhysicalAddress::physical_page_index(highest_physical_address.get()) + 1;
VERIFY(m_physical_page_entries_count != 0);
VERIFY(!Checked<decltype(m_physical_page_entries_count)>::multiplication_would_overflow(m_physical_page_entries_count, sizeof(PhysicalPageEntry)));
// Calculate how many bytes the array will consume
auto physical_page_array_size = m_physical_page_entries_count * sizeof(PhysicalPageEntry);
auto physical_page_array_pages = page_round_up(physical_page_array_size).release_value_but_fixme_should_propagate_errors() / PAGE_SIZE;
VERIFY(physical_page_array_pages * PAGE_SIZE >= physical_page_array_size);
// Calculate how many page tables we will need to be able to map them all
auto needed_page_table_count = (physical_page_array_pages + 512 - 1) / 512;
auto physical_page_array_pages_and_page_tables_count = physical_page_array_pages + needed_page_table_count;
// Now that we know how much memory we need for a contiguous array of PhysicalPage instances, find a memory region that can fit it
PhysicalRegion* found_region { nullptr };
Optional<size_t> found_region_index;
for (size_t i = 0; i < global_data.physical_regions.size(); ++i) {
auto& region = global_data.physical_regions[i];
if (region.size() >= physical_page_array_pages_and_page_tables_count) {
found_region = &region;
found_region_index = i;
break;
}
}
if (!found_region) {
dmesgln("MM: Need {} bytes for physical page management, but no memory region is large enough!", physical_page_array_pages_and_page_tables_count);
VERIFY_NOT_REACHED();
}
VERIFY(global_data.system_memory_info.physical_pages >= physical_page_array_pages_and_page_tables_count);
global_data.system_memory_info.physical_pages -= physical_page_array_pages_and_page_tables_count;
if (found_region->size() == physical_page_array_pages_and_page_tables_count) {
// We're stealing the entire region
global_data.physical_pages_region = global_data.physical_regions.take(*found_region_index);
} else {
global_data.physical_pages_region = found_region->try_take_pages_from_beginning(physical_page_array_pages_and_page_tables_count);
}
global_data.used_memory_ranges.append({ UsedMemoryRangeType::PhysicalPages, global_data.physical_pages_region->lower(), global_data.physical_pages_region->upper() });
// Create the bare page directory. This is not a fully constructed page directory and merely contains the allocators!
m_kernel_page_directory = PageDirectory::must_create_kernel_page_directory();
{
// Carve out the whole page directory covering the kernel image to make MemoryManager::initialize_physical_pages() happy
FlatPtr start_of_range = ((FlatPtr)start_of_kernel_image & ~(FlatPtr)0x1fffff);
FlatPtr end_of_range = ((FlatPtr)end_of_kernel_image & ~(FlatPtr)0x1fffff) + 0x200000;
MUST(global_data.region_tree.place_specifically(*MUST(Region::create_unbacked()).leak_ptr(), VirtualRange { VirtualAddress(start_of_range), end_of_range - start_of_range }));
}
// Allocate a virtual address range for our array
// This looks awkward, but it basically creates a dummy region to occupy the address range permanently.
auto& region = *MUST(Region::create_unbacked()).leak_ptr();
MUST(global_data.region_tree.place_anywhere(region, RandomizeVirtualAddress::No, physical_page_array_pages * PAGE_SIZE));
auto range = region.range();
// Now that we have our special m_physical_pages_region region with enough pages to hold the entire array
// try to map the entire region into kernel space so we always have it
// We can't use ensure_pte here because it would try to allocate a PhysicalPage and we don't have the array
// mapped yet so we can't create them
// Create page tables at the beginning of m_physical_pages_region, followed by the PhysicalPageEntry array
auto page_tables_base = global_data.physical_pages_region->lower();
auto physical_page_array_base = page_tables_base.offset(needed_page_table_count * PAGE_SIZE);
auto physical_page_array_current_page = physical_page_array_base.get();
auto virtual_page_array_base = range.base().get();
auto virtual_page_array_current_page = virtual_page_array_base;
for (size_t pt_index = 0; pt_index < needed_page_table_count; pt_index++) {
auto virtual_page_base_for_this_pt = virtual_page_array_current_page;
auto pt_paddr = page_tables_base.offset(pt_index * PAGE_SIZE);
auto* pt = reinterpret_cast<PageTableEntry*>(quickmap_page(pt_paddr));
__builtin_memset(pt, 0, PAGE_SIZE);
for (size_t pte_index = 0; pte_index < PAGE_SIZE / sizeof(PageTableEntry); pte_index++) {
auto& pte = pt[pte_index];
pte.set_physical_page_base(physical_page_array_current_page);
pte.set_user_allowed(false);
pte.set_writable(true);
if (Processor::current().has_nx())
pte.set_execute_disabled(false);
pte.set_global(true);
pte.set_present(true);
physical_page_array_current_page += PAGE_SIZE;
virtual_page_array_current_page += PAGE_SIZE;
}
unquickmap_page();
// Hook the page table into the kernel page directory
u32 page_directory_index = (virtual_page_base_for_this_pt >> 21) & 0x1ff;
auto* pd = reinterpret_cast<PageDirectoryEntry*>(quickmap_page(boot_pd_kernel));
PageDirectoryEntry& pde = pd[page_directory_index];
VERIFY(!pde.is_present()); // Nothing should be using this PD yet
// We can't use ensure_pte quite yet!
pde.set_page_table_base(pt_paddr.get());
pde.set_user_allowed(false);
pde.set_present(true);
pde.set_writable(true);
pde.set_global(true);
unquickmap_page();
flush_tlb_local(VirtualAddress(virtual_page_base_for_this_pt));
}
// We now have the entire PhysicalPageEntry array mapped!
m_physical_page_entries = (PhysicalPageEntry*)range.base().get();
for (size_t i = 0; i < m_physical_page_entries_count; i++)
new (&m_physical_page_entries[i]) PageTableEntry();
// Now we should be able to allocate PhysicalPage instances,
// so finish setting up the kernel page directory
m_kernel_page_directory->allocate_kernel_directory();
// Now create legit PhysicalPage objects for the page tables we created.
virtual_page_array_current_page = virtual_page_array_base;
for (size_t pt_index = 0; pt_index < needed_page_table_count; pt_index++) {
VERIFY(virtual_page_array_current_page <= range.end().get());
auto pt_paddr = page_tables_base.offset(pt_index * PAGE_SIZE);
auto physical_page_index = PhysicalAddress::physical_page_index(pt_paddr.get());
auto& physical_page_entry = m_physical_page_entries[physical_page_index];
auto physical_page = adopt_lock_ref(*new (&physical_page_entry.allocated.physical_page) PhysicalPage(MayReturnToFreeList::No));
// NOTE: This leaked ref is matched by the unref in MemoryManager::release_pte()
(void)physical_page.leak_ref();
virtual_page_array_current_page += (PAGE_SIZE / sizeof(PageTableEntry)) * PAGE_SIZE;
}
dmesgln("MM: Physical page entries: {}", range);
});
}
PhysicalPageEntry& MemoryManager::get_physical_page_entry(PhysicalAddress physical_address)
{
auto physical_page_entry_index = PhysicalAddress::physical_page_index(physical_address.get());
VERIFY(physical_page_entry_index < m_physical_page_entries_count);
return m_physical_page_entries[physical_page_entry_index];
}
PhysicalAddress MemoryManager::get_physical_address(PhysicalPage const& physical_page)
{
PhysicalPageEntry const& physical_page_entry = *reinterpret_cast<PhysicalPageEntry const*>((u8 const*)&physical_page - __builtin_offsetof(PhysicalPageEntry, allocated.physical_page));
size_t physical_page_entry_index = &physical_page_entry - m_physical_page_entries;
VERIFY(physical_page_entry_index < m_physical_page_entries_count);
return PhysicalAddress((PhysicalPtr)physical_page_entry_index * PAGE_SIZE);
}
PageTableEntry* MemoryManager::pte(PageDirectory& page_directory, VirtualAddress vaddr)
{
VERIFY_INTERRUPTS_DISABLED();
VERIFY(page_directory.get_lock().is_locked_by_current_processor());
u32 page_directory_table_index = (vaddr.get() >> 30) & 0x1ff;
u32 page_directory_index = (vaddr.get() >> 21) & 0x1ff;
u32 page_table_index = (vaddr.get() >> 12) & 0x1ff;
auto* pd = quickmap_pd(const_cast<PageDirectory&>(page_directory), page_directory_table_index);
PageDirectoryEntry const& pde = pd[page_directory_index];
if (!pde.is_present())
return nullptr;
return &quickmap_pt(PhysicalAddress((FlatPtr)pde.page_table_base()))[page_table_index];
}
PageTableEntry* MemoryManager::ensure_pte(PageDirectory& page_directory, VirtualAddress vaddr)
{
VERIFY_INTERRUPTS_DISABLED();
VERIFY(page_directory.get_lock().is_locked_by_current_processor());
u32 page_directory_table_index = (vaddr.get() >> 30) & 0x1ff;
u32 page_directory_index = (vaddr.get() >> 21) & 0x1ff;
u32 page_table_index = (vaddr.get() >> 12) & 0x1ff;
auto* pd = quickmap_pd(page_directory, page_directory_table_index);
auto& pde = pd[page_directory_index];
if (pde.is_present())
return &quickmap_pt(PhysicalAddress(pde.page_table_base()))[page_table_index];
bool did_purge = false;
auto page_table_or_error = allocate_physical_page(ShouldZeroFill::Yes, &did_purge);
if (page_table_or_error.is_error()) {
dbgln("MM: Unable to allocate page table to map {}", vaddr);
return nullptr;
}
auto page_table = page_table_or_error.release_value();
if (did_purge) {
// If any memory had to be purged, ensure_pte may have been called as part
// of the purging process. So we need to re-map the pd in this case to ensure
// we're writing to the correct underlying physical page
pd = quickmap_pd(page_directory, page_directory_table_index);
VERIFY(&pde == &pd[page_directory_index]); // Sanity check
VERIFY(!pde.is_present()); // Should have not changed
}
pde.set_page_table_base(page_table->paddr().get());
pde.set_user_allowed(true);
pde.set_present(true);
pde.set_writable(true);
pde.set_global(&page_directory == m_kernel_page_directory.ptr());
// NOTE: This leaked ref is matched by the unref in MemoryManager::release_pte()
(void)page_table.leak_ref();
return &quickmap_pt(PhysicalAddress(pde.page_table_base()))[page_table_index];
}
void MemoryManager::release_pte(PageDirectory& page_directory, VirtualAddress vaddr, IsLastPTERelease is_last_pte_release)
{
VERIFY_INTERRUPTS_DISABLED();
VERIFY(page_directory.get_lock().is_locked_by_current_processor());
u32 page_directory_table_index = (vaddr.get() >> 30) & 0x1ff;
u32 page_directory_index = (vaddr.get() >> 21) & 0x1ff;
u32 page_table_index = (vaddr.get() >> 12) & 0x1ff;
auto* pd = quickmap_pd(page_directory, page_directory_table_index);
PageDirectoryEntry& pde = pd[page_directory_index];
if (pde.is_present()) {
auto* page_table = quickmap_pt(PhysicalAddress((FlatPtr)pde.page_table_base()));
auto& pte = page_table[page_table_index];
pte.clear();
if (is_last_pte_release == IsLastPTERelease::Yes || page_table_index == 0x1ff) {
// If this is the last PTE in a region or the last PTE in a page table then
// check if we can also release the page table
bool all_clear = true;
for (u32 i = 0; i <= 0x1ff; i++) {
if (!page_table[i].is_null()) {
all_clear = false;
break;
}
}
if (all_clear) {
get_physical_page_entry(PhysicalAddress { pde.page_table_base() }).allocated.physical_page.unref();
pde.clear();
}
}
}
}
UNMAP_AFTER_INIT void MemoryManager::initialize(u32 cpu)
{
ProcessorSpecific<MemoryManagerData>::initialize();
if (cpu == 0) {
new MemoryManager;
kmalloc_enable_expand();
}
}
Region* MemoryManager::kernel_region_from_vaddr(VirtualAddress address)
{
if (is_user_address(address))
return nullptr;
return MM.m_global_data.with([&](auto& global_data) {
return global_data.region_tree.find_region_containing(address);
});
}
Region* MemoryManager::find_user_region_from_vaddr(AddressSpace& space, VirtualAddress vaddr)
{
return space.find_region_containing({ vaddr, 1 });
}
void MemoryManager::validate_syscall_preconditions(Process& process, RegisterState const& regs)
{
bool should_crash = false;
char const* crash_description = nullptr;
int crash_signal = 0;
auto unlock_and_handle_crash = [&](char const* description, int signal) {
should_crash = true;
crash_description = description;
crash_signal = signal;
};
process.address_space().with([&](auto& space) -> void {
VirtualAddress userspace_sp = VirtualAddress { regs.userspace_sp() };
if (!MM.validate_user_stack(*space, userspace_sp)) {
dbgln("Invalid stack pointer: {}", userspace_sp);
return unlock_and_handle_crash("Bad stack on syscall entry", SIGSEGV);
}
VirtualAddress ip = VirtualAddress { regs.ip() };
auto* calling_region = MM.find_user_region_from_vaddr(*space, ip);
if (!calling_region) {
dbgln("Syscall from {:p} which has no associated region", ip);
return unlock_and_handle_crash("Syscall from unknown region", SIGSEGV);
}
if (calling_region->is_writable()) {
dbgln("Syscall from writable memory at {:p}", ip);
return unlock_and_handle_crash("Syscall from writable memory", SIGSEGV);
}
if (space->enforces_syscall_regions() && !calling_region->is_syscall_region()) {
dbgln("Syscall from non-syscall region");
return unlock_and_handle_crash("Syscall from non-syscall region", SIGSEGV);
}
});
if (should_crash) {
handle_crash(regs, crash_description, crash_signal);
}
}
Region* MemoryManager::find_region_from_vaddr(VirtualAddress vaddr)
{
if (auto* region = kernel_region_from_vaddr(vaddr))
return region;
auto page_directory = PageDirectory::find_current();
if (!page_directory)
return nullptr;
VERIFY(page_directory->address_space());
return find_user_region_from_vaddr(*page_directory->address_space(), vaddr);
}
PageFaultResponse MemoryManager::handle_page_fault(PageFault const& fault)
{
auto faulted_in_range = [&fault](auto const* start, auto const* end) {
return fault.vaddr() >= VirtualAddress { start } && fault.vaddr() < VirtualAddress { end };
};
if (faulted_in_range(&start_of_ro_after_init, &end_of_ro_after_init))
PANIC("Attempt to write into READONLY_AFTER_INIT section");
if (faulted_in_range(&start_of_unmap_after_init, &end_of_unmap_after_init)) {
auto const* kernel_symbol = symbolicate_kernel_address(fault.vaddr().get());
PANIC("Attempt to access UNMAP_AFTER_INIT section ({:p}: {})", fault.vaddr(), kernel_symbol ? kernel_symbol->name : "(Unknown)");
}
if (faulted_in_range(&start_of_kernel_ksyms, &end_of_kernel_ksyms))
PANIC("Attempt to access KSYMS section");
if (Processor::current_in_irq()) {
dbgln("CPU[{}] BUG! Page fault while handling IRQ! code={}, vaddr={}, irq level: {}",
Processor::current_id(), fault.code(), fault.vaddr(), Processor::current_in_irq());
dump_kernel_regions();
return PageFaultResponse::ShouldCrash;
}
dbgln_if(PAGE_FAULT_DEBUG, "MM: CPU[{}] handle_page_fault({:#04x}) at {}", Processor::current_id(), fault.code(), fault.vaddr());
auto* region = find_region_from_vaddr(fault.vaddr());
if (!region) {
return PageFaultResponse::ShouldCrash;
}
return region->handle_fault(fault);
}
ErrorOr<NonnullOwnPtr<Region>> MemoryManager::allocate_contiguous_kernel_region(size_t size, StringView name, Region::Access access, Region::Cacheable cacheable)
{
VERIFY(!(size % PAGE_SIZE));
OwnPtr<KString> name_kstring;
if (!name.is_null())
name_kstring = TRY(KString::try_create(name));
auto vmobject = TRY(AnonymousVMObject::try_create_physically_contiguous_with_size(size));
auto region = TRY(Region::create_unplaced(move(vmobject), 0, move(name_kstring), access, cacheable));
TRY(m_global_data.with([&](auto& global_data) { return global_data.region_tree.place_anywhere(*region, RandomizeVirtualAddress::No, size); }));
TRY(region->map(kernel_page_directory()));
return region;
}
ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::allocate_dma_buffer_page(StringView name, Memory::Region::Access access, RefPtr<Memory::PhysicalPage>& dma_buffer_page)
{
dma_buffer_page = TRY(allocate_physical_page());
// Do not enable Cache for this region as physical memory transfers are performed (Most architectures have this behaviour by default)
return allocate_kernel_region(dma_buffer_page->paddr(), PAGE_SIZE, name, access, Region::Cacheable::No);
}
ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::allocate_dma_buffer_page(StringView name, Memory::Region::Access access)
{
RefPtr<Memory::PhysicalPage> dma_buffer_page;
return allocate_dma_buffer_page(name, access, dma_buffer_page);
}
ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::allocate_dma_buffer_pages(size_t size, StringView name, Memory::Region::Access access, NonnullRefPtrVector<Memory::PhysicalPage>& dma_buffer_pages)
{
VERIFY(!(size % PAGE_SIZE));
dma_buffer_pages = TRY(allocate_contiguous_physical_pages(size));
// Do not enable Cache for this region as physical memory transfers are performed (Most architectures have this behaviour by default)
return allocate_kernel_region(dma_buffer_pages.first().paddr(), size, name, access, Region::Cacheable::No);
}
ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::allocate_dma_buffer_pages(size_t size, StringView name, Memory::Region::Access access)
{
VERIFY(!(size % PAGE_SIZE));
NonnullRefPtrVector<Memory::PhysicalPage> dma_buffer_pages;
return allocate_dma_buffer_pages(size, name, access, dma_buffer_pages);
}
ErrorOr<NonnullOwnPtr<Region>> MemoryManager::allocate_kernel_region(size_t size, StringView name, Region::Access access, AllocationStrategy strategy, Region::Cacheable cacheable)
{
VERIFY(!(size % PAGE_SIZE));
OwnPtr<KString> name_kstring;
if (!name.is_null())
name_kstring = TRY(KString::try_create(name));
auto vmobject = TRY(AnonymousVMObject::try_create_with_size(size, strategy));
auto region = TRY(Region::create_unplaced(move(vmobject), 0, move(name_kstring), access, cacheable));
TRY(m_global_data.with([&](auto& global_data) { return global_data.region_tree.place_anywhere(*region, RandomizeVirtualAddress::No, size); }));
TRY(region->map(kernel_page_directory()));
return region;
}
ErrorOr<NonnullOwnPtr<Region>> MemoryManager::allocate_kernel_region(PhysicalAddress paddr, size_t size, StringView name, Region::Access access, Region::Cacheable cacheable)
{
VERIFY(!(size % PAGE_SIZE));
auto vmobject = TRY(AnonymousVMObject::try_create_for_physical_range(paddr, size));
OwnPtr<KString> name_kstring;
if (!name.is_null())
name_kstring = TRY(KString::try_create(name));
auto region = TRY(Region::create_unplaced(move(vmobject), 0, move(name_kstring), access, cacheable));
TRY(m_global_data.with([&](auto& global_data) { return global_data.region_tree.place_anywhere(*region, RandomizeVirtualAddress::No, size, PAGE_SIZE); }));
TRY(region->map(kernel_page_directory()));
return region;
}
ErrorOr<NonnullOwnPtr<Region>> MemoryManager::allocate_kernel_region_with_vmobject(VMObject& vmobject, size_t size, StringView name, Region::Access access, Region::Cacheable cacheable)
{
VERIFY(!(size % PAGE_SIZE));
OwnPtr<KString> name_kstring;
if (!name.is_null())
name_kstring = TRY(KString::try_create(name));
auto region = TRY(Region::create_unplaced(vmobject, 0, move(name_kstring), access, cacheable));
TRY(m_global_data.with([&](auto& global_data) { return global_data.region_tree.place_anywhere(*region, RandomizeVirtualAddress::No, size); }));
TRY(region->map(kernel_page_directory()));
return region;
}
ErrorOr<CommittedPhysicalPageSet> MemoryManager::commit_physical_pages(size_t page_count)
{
VERIFY(page_count > 0);
auto result = m_global_data.with([&](auto& global_data) -> ErrorOr<CommittedPhysicalPageSet> {
if (global_data.system_memory_info.physical_pages_uncommitted < page_count) {
dbgln("MM: Unable to commit {} pages, have only {}", page_count, global_data.system_memory_info.physical_pages_uncommitted);
return ENOMEM;
}
global_data.system_memory_info.physical_pages_uncommitted -= page_count;
global_data.system_memory_info.physical_pages_committed += page_count;
return CommittedPhysicalPageSet { {}, page_count };
});
if (result.is_error()) {
Process::for_each([&](Process const& process) {
size_t amount_resident = 0;
size_t amount_shared = 0;
size_t amount_virtual = 0;
process.address_space().with([&](auto& space) {
amount_resident = space->amount_resident();
amount_shared = space->amount_shared();
amount_virtual = space->amount_virtual();
});
dbgln("{}({}) resident:{}, shared:{}, virtual:{}",
process.name(),
process.pid(),
amount_resident / PAGE_SIZE,
amount_shared / PAGE_SIZE,
amount_virtual / PAGE_SIZE);
return IterationDecision::Continue;
});
}
return result;
}
void MemoryManager::uncommit_physical_pages(Badge<CommittedPhysicalPageSet>, size_t page_count)
{
VERIFY(page_count > 0);
m_global_data.with([&](auto& global_data) {
VERIFY(global_data.system_memory_info.physical_pages_committed >= page_count);
global_data.system_memory_info.physical_pages_uncommitted += page_count;
global_data.system_memory_info.physical_pages_committed -= page_count;
});
}
void MemoryManager::deallocate_physical_page(PhysicalAddress paddr)
{
return m_global_data.with([&](auto& global_data) {
// Are we returning a user page?
for (auto& region : global_data.physical_regions) {
if (!region.contains(paddr))
continue;
region.return_page(paddr);
--global_data.system_memory_info.physical_pages_used;
// Always return pages to the uncommitted pool. Pages that were
// committed and allocated are only freed upon request. Once
// returned there is no guarantee being able to get them back.
++global_data.system_memory_info.physical_pages_uncommitted;
return;
}
PANIC("MM: deallocate_physical_page couldn't figure out region for page @ {}", paddr);
});
}
RefPtr<PhysicalPage> MemoryManager::find_free_physical_page(bool committed)
{
RefPtr<PhysicalPage> page;
m_global_data.with([&](auto& global_data) {
if (committed) {
// Draw from the committed pages pool. We should always have these pages available
VERIFY(global_data.system_memory_info.physical_pages_committed > 0);
global_data.system_memory_info.physical_pages_committed--;
} else {
// We need to make sure we don't touch pages that we have committed to
if (global_data.system_memory_info.physical_pages_uncommitted == 0)
return;
global_data.system_memory_info.physical_pages_uncommitted--;
}
for (auto& region : global_data.physical_regions) {
page = region.take_free_page();
if (!page.is_null()) {
++global_data.system_memory_info.physical_pages_used;
break;
}
}
});
VERIFY(!page.is_null());
return page;
}
NonnullRefPtr<PhysicalPage> MemoryManager::allocate_committed_physical_page(Badge<CommittedPhysicalPageSet>, ShouldZeroFill should_zero_fill)
{
auto page = find_free_physical_page(true);
if (should_zero_fill == ShouldZeroFill::Yes) {
InterruptDisabler disabler;
auto* ptr = quickmap_page(*page);
memset(ptr, 0, PAGE_SIZE);
unquickmap_page();
}
return page.release_nonnull();
}
ErrorOr<NonnullRefPtr<PhysicalPage>> MemoryManager::allocate_physical_page(ShouldZeroFill should_zero_fill, bool* did_purge)
{
return m_global_data.with([&](auto&) -> ErrorOr<NonnullRefPtr<PhysicalPage>> {
auto page = find_free_physical_page(false);
bool purged_pages = false;
if (!page) {
// We didn't have a single free physical page. Let's try to free something up!
// First, we look for a purgeable VMObject in the volatile state.
for_each_vmobject([&](auto& vmobject) {
if (!vmobject.is_anonymous())
return IterationDecision::Continue;
auto& anonymous_vmobject = static_cast<AnonymousVMObject&>(vmobject);
if (!anonymous_vmobject.is_purgeable() || !anonymous_vmobject.is_volatile())
return IterationDecision::Continue;
if (auto purged_page_count = anonymous_vmobject.purge()) {
dbgln("MM: Purge saved the day! Purged {} pages from AnonymousVMObject", purged_page_count);
page = find_free_physical_page(false);
purged_pages = true;
VERIFY(page);
return IterationDecision::Break;
}
return IterationDecision::Continue;
});
}
if (!page) {
// Second, we look for a file-backed VMObject with clean pages.
for_each_vmobject([&](auto& vmobject) {
if (!vmobject.is_inode())
return IterationDecision::Continue;
auto& inode_vmobject = static_cast<InodeVMObject&>(vmobject);
if (auto released_page_count = inode_vmobject.try_release_clean_pages(1)) {
dbgln("MM: Clean inode release saved the day! Released {} pages from InodeVMObject", released_page_count);
page = find_free_physical_page(false);
VERIFY(page);
return IterationDecision::Break;
}
return IterationDecision::Continue;
});
}
if (!page) {
dmesgln("MM: no physical pages available");
return ENOMEM;
}
if (should_zero_fill == ShouldZeroFill::Yes) {
auto* ptr = quickmap_page(*page);
memset(ptr, 0, PAGE_SIZE);
unquickmap_page();
}
if (did_purge)
*did_purge = purged_pages;
return page.release_nonnull();
});
}
ErrorOr<NonnullRefPtrVector<PhysicalPage>> MemoryManager::allocate_contiguous_physical_pages(size_t size)
{
VERIFY(!(size % PAGE_SIZE));
size_t page_count = ceil_div(size, static_cast<size_t>(PAGE_SIZE));
auto physical_pages = TRY(m_global_data.with([&](auto& global_data) -> ErrorOr<NonnullRefPtrVector<PhysicalPage>> {
// We need to make sure we don't touch pages that we have committed to
if (global_data.system_memory_info.physical_pages_uncommitted < page_count)
return ENOMEM;
for (auto& physical_region : global_data.physical_regions) {
auto physical_pages = physical_region.take_contiguous_free_pages(page_count);
if (!physical_pages.is_empty()) {
global_data.system_memory_info.physical_pages_uncommitted -= page_count;
global_data.system_memory_info.physical_pages_used += page_count;
return physical_pages;
}
}
dmesgln("MM: no contiguous physical pages available");
return ENOMEM;
}));
{
auto cleanup_region = TRY(MM.allocate_kernel_region(physical_pages[0].paddr(), PAGE_SIZE * page_count, {}, Region::Access::Read | Region::Access::Write));
memset(cleanup_region->vaddr().as_ptr(), 0, PAGE_SIZE * page_count);
}
return physical_pages;
}
void MemoryManager::enter_process_address_space(Process& process)
{
process.address_space().with([](auto& space) {
enter_address_space(*space);
});
}
void MemoryManager::enter_address_space(AddressSpace& space)
{
auto* current_thread = Thread::current();
VERIFY(current_thread != nullptr);
activate_page_directory(space.page_directory(), current_thread);
}
void MemoryManager::flush_tlb_local(VirtualAddress vaddr, size_t page_count)
{
Processor::flush_tlb_local(vaddr, page_count);
}
void MemoryManager::flush_tlb(PageDirectory const* page_directory, VirtualAddress vaddr, size_t page_count)
{
Processor::flush_tlb(page_directory, vaddr, page_count);
}
PageDirectoryEntry* MemoryManager::quickmap_pd(PageDirectory& directory, size_t pdpt_index)
{
VERIFY_INTERRUPTS_DISABLED();
VirtualAddress vaddr(KERNEL_QUICKMAP_PD_PER_CPU_BASE + Processor::current_id() * PAGE_SIZE);
size_t pte_index = (vaddr.get() - KERNEL_PT1024_BASE) / PAGE_SIZE;
auto& pte = boot_pd_kernel_pt1023[pte_index];
auto pd_paddr = directory.m_directory_pages[pdpt_index]->paddr();
if (pte.physical_page_base() != pd_paddr.get()) {
pte.set_physical_page_base(pd_paddr.get());
pte.set_present(true);
pte.set_writable(true);
pte.set_user_allowed(false);
flush_tlb_local(vaddr);
}
return (PageDirectoryEntry*)vaddr.get();
}
PageTableEntry* MemoryManager::quickmap_pt(PhysicalAddress pt_paddr)
{
VERIFY_INTERRUPTS_DISABLED();
VirtualAddress vaddr(KERNEL_QUICKMAP_PT_PER_CPU_BASE + Processor::current_id() * PAGE_SIZE);
size_t pte_index = (vaddr.get() - KERNEL_PT1024_BASE) / PAGE_SIZE;
auto& pte = ((PageTableEntry*)boot_pd_kernel_pt1023)[pte_index];
if (pte.physical_page_base() != pt_paddr.get()) {
pte.set_physical_page_base(pt_paddr.get());
pte.set_present(true);
pte.set_writable(true);
pte.set_user_allowed(false);
flush_tlb_local(vaddr);
}
return (PageTableEntry*)vaddr.get();
}
u8* MemoryManager::quickmap_page(PhysicalAddress const& physical_address)
{
VERIFY_INTERRUPTS_DISABLED();
auto& mm_data = get_data();
mm_data.m_quickmap_previous_interrupts_state = mm_data.m_quickmap_in_use.lock();
VirtualAddress vaddr(KERNEL_QUICKMAP_PER_CPU_BASE + Processor::current_id() * PAGE_SIZE);
u32 pte_idx = (vaddr.get() - KERNEL_PT1024_BASE) / PAGE_SIZE;
auto& pte = ((PageTableEntry*)boot_pd_kernel_pt1023)[pte_idx];
if (pte.physical_page_base() != physical_address.get()) {
pte.set_physical_page_base(physical_address.get());
pte.set_present(true);
pte.set_writable(true);
pte.set_user_allowed(false);
flush_tlb_local(vaddr);
}
return vaddr.as_ptr();
}
void MemoryManager::unquickmap_page()
{
VERIFY_INTERRUPTS_DISABLED();
auto& mm_data = get_data();
VERIFY(mm_data.m_quickmap_in_use.is_locked());
VirtualAddress vaddr(KERNEL_QUICKMAP_PER_CPU_BASE + Processor::current_id() * PAGE_SIZE);
u32 pte_idx = (vaddr.get() - KERNEL_PT1024_BASE) / PAGE_SIZE;
auto& pte = ((PageTableEntry*)boot_pd_kernel_pt1023)[pte_idx];
pte.clear();
flush_tlb_local(vaddr);
mm_data.m_quickmap_in_use.unlock(mm_data.m_quickmap_previous_interrupts_state);
}
bool MemoryManager::validate_user_stack(AddressSpace& space, VirtualAddress vaddr) const
{
if (!is_user_address(vaddr))
return false;
auto* region = find_user_region_from_vaddr(space, vaddr);
return region && region->is_user() && region->is_stack();
}
void MemoryManager::unregister_kernel_region(Region& region)
{
VERIFY(region.is_kernel());
m_global_data.with([&](auto& global_data) { global_data.region_tree.remove(region); });
}
void MemoryManager::dump_kernel_regions()
{
dbgln("Kernel regions:");
#if ARCH(I386)
char const* addr_padding = "";
#else
char const* addr_padding = " ";
#endif
dbgln("BEGIN{} END{} SIZE{} ACCESS NAME",
addr_padding, addr_padding, addr_padding);
m_global_data.with([&](auto& global_data) {
for (auto& region : global_data.region_tree.regions()) {
dbgln("{:p} -- {:p} {:p} {:c}{:c}{:c}{:c}{:c}{:c} {}",
region.vaddr().get(),
region.vaddr().offset(region.size() - 1).get(),
region.size(),
region.is_readable() ? 'R' : ' ',
region.is_writable() ? 'W' : ' ',
region.is_executable() ? 'X' : ' ',
region.is_shared() ? 'S' : ' ',
region.is_stack() ? 'T' : ' ',
region.is_syscall_region() ? 'C' : ' ',
region.name());
}
});
}
void MemoryManager::set_page_writable_direct(VirtualAddress vaddr, bool writable)
{
SpinlockLocker page_lock(kernel_page_directory().get_lock());
auto* pte = ensure_pte(kernel_page_directory(), vaddr);
VERIFY(pte);
if (pte->is_writable() == writable)
return;
pte->set_writable(writable);
flush_tlb(&kernel_page_directory(), vaddr);
}
CommittedPhysicalPageSet::~CommittedPhysicalPageSet()
{
if (m_page_count)
MM.uncommit_physical_pages({}, m_page_count);
}
NonnullRefPtr<PhysicalPage> CommittedPhysicalPageSet::take_one()
{
VERIFY(m_page_count > 0);
--m_page_count;
return MM.allocate_committed_physical_page({}, MemoryManager::ShouldZeroFill::Yes);
}
void CommittedPhysicalPageSet::uncommit_one()
{
VERIFY(m_page_count > 0);
--m_page_count;
MM.uncommit_physical_pages({}, 1);
}
void MemoryManager::copy_physical_page(PhysicalPage& physical_page, u8 page_buffer[PAGE_SIZE])
{
auto* quickmapped_page = quickmap_page(physical_page);
memcpy(page_buffer, quickmapped_page, PAGE_SIZE);
unquickmap_page();
}
ErrorOr<NonnullOwnPtr<Memory::Region>> MemoryManager::create_identity_mapped_region(PhysicalAddress address, size_t size)
{
auto vmobject = TRY(Memory::AnonymousVMObject::try_create_for_physical_range(address, size));
auto region = TRY(Memory::Region::create_unplaced(move(vmobject), 0, {}, Memory::Region::Access::ReadWriteExecute));
Memory::VirtualRange range { VirtualAddress { (FlatPtr)address.get() }, size };
region->m_range = range;
TRY(region->map(MM.kernel_page_directory()));
return region;
}
ErrorOr<NonnullOwnPtr<Region>> MemoryManager::allocate_unbacked_region_anywhere(size_t size, size_t alignment)
{
auto region = TRY(Region::create_unbacked());
TRY(m_global_data.with([&](auto& global_data) { return global_data.region_tree.place_anywhere(*region, RandomizeVirtualAddress::No, size, alignment); }));
return region;
}
MemoryManager::SystemMemoryInfo MemoryManager::get_system_memory_info()
{
return m_global_data.with([&](auto& global_data) {
auto physical_pages_unused = global_data.system_memory_info.physical_pages_committed + global_data.system_memory_info.physical_pages_uncommitted;
VERIFY(global_data.system_memory_info.physical_pages == (global_data.system_memory_info.physical_pages_used + physical_pages_unused));
return global_data.system_memory_info;
});
}
}
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