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-rw-r--r--Kernel/MemoryManager.cpp61
-rw-r--r--Kernel/MemoryManager.h5
-rw-r--r--Kernel/i386.h9
3 files changed, 47 insertions, 28 deletions
diff --git a/Kernel/MemoryManager.cpp b/Kernel/MemoryManager.cpp
index f4314bf557..1321469428 100644
--- a/Kernel/MemoryManager.cpp
+++ b/Kernel/MemoryManager.cpp
@@ -54,7 +54,6 @@ PageDirectory::PageDirectory()
void MemoryManager::populate_page_directory(PageDirectory& page_directory)
{
page_directory.m_directory_page = allocate_supervisor_physical_page();
- memset(page_directory.entries(), 0, PAGE_SIZE);
page_directory.entries()[0] = kernel_page_directory().entries()[0];
}
@@ -83,6 +82,7 @@ void MemoryManager::initialize_paging()
// Basic memory map:
// 0 -> 512 kB Kernel code. Root page directory & PDE 0.
+ // (last page before 1MB) Used by quickmap_page().
// 1 MB -> 2 MB kmalloc_eternal() space.
// 2 MB -> 3 MB kmalloc() space.
// 3 MB -> 4 MB Supervisor physical pages (available for allocation!)
@@ -93,17 +93,17 @@ void MemoryManager::initialize_paging()
dbgprintf("MM: 4MB-%uMB available for allocation\n", m_ram_size / 1048576);
for (size_t i = (4 * MB); i < m_ram_size; i += PAGE_SIZE)
m_free_physical_pages.append(adopt(*new PhysicalPage(PhysicalAddress(i), false)));
- m_quickmap_addr = LinearAddress(m_free_physical_pages.take_last().leakRef()->paddr().get());
+ m_quickmap_addr = LinearAddress((1 * MB) - PAGE_SIZE);
#ifdef MM_DEBUG
dbgprintf("MM: Quickmap will use P%x\n", m_quickmap_addr.get());
dbgprintf("MM: Installing page directory\n");
#endif
asm volatile("movl %%eax, %%cr3"::"a"(kernel_page_directory().cr3()));
asm volatile(
- "movl %cr0, %eax\n"
- "orl $0x80000001, %eax\n"
- "movl %eax, %cr0\n"
- );
+ "movl %%cr0, %%eax\n"
+ "orl $0x80000001, %%eax\n"
+ "movl %%eax, %%cr0\n"
+ :::"%eax", "memory");
}
RetainPtr<PhysicalPage> MemoryManager::allocate_page_table(PageDirectory& page_directory, unsigned index)
@@ -112,8 +112,6 @@ RetainPtr<PhysicalPage> MemoryManager::allocate_page_table(PageDirectory& page_d
auto physical_page = allocate_supervisor_physical_page();
if (!physical_page)
return nullptr;
- dword address = physical_page->paddr().get();
- memset((void*)address, 0, PAGE_SIZE);
page_directory.m_physical_pages.set(index, physical_page.copyRef());
return physical_page;
}
@@ -236,13 +234,10 @@ bool MemoryManager::zero_page(Region& region, unsigned page_index_in_region)
{
ASSERT_INTERRUPTS_DISABLED();
auto& vmo = region.vmo();
- auto physical_page = allocate_physical_page();
- byte* dest_ptr = quickmap_page(*physical_page);
- memset(dest_ptr, 0, PAGE_SIZE);
+ auto physical_page = allocate_physical_page(ShouldZeroFill::Yes);
#ifdef PAGE_FAULT_DEBUG
dbgprintf(" >> ZERO P%x\n", physical_page->paddr().get());
#endif
- unquickmap_page();
region.m_cow_map.set(page_index_in_region, false);
vmo.physical_pages()[page_index_in_region] = move(physical_page);
remap_region_page(region, page_index_in_region, true);
@@ -266,7 +261,7 @@ bool MemoryManager::copy_on_write(Region& region, unsigned page_index_in_region)
dbgprintf(" >> It's a COW page and it's time to COW!\n");
#endif
auto physical_page_to_copy = move(vmo.physical_pages()[page_index_in_region]);
- auto physical_page = allocate_physical_page();
+ auto physical_page = allocate_physical_page(ShouldZeroFill::No);
byte* dest_ptr = quickmap_page(*physical_page);
const byte* src_ptr = region.laddr().offset(page_index_in_region * PAGE_SIZE).as_ptr();
#ifdef PAGE_FAULT_DEBUG
@@ -309,7 +304,7 @@ bool MemoryManager::page_in_from_inode(Region& region, unsigned page_index_in_re
auto& inode = *vmo.inode();
auto& vmo_page = vmo.physical_pages()[region.first_page_index() + page_index_in_region];
ASSERT(vmo_page.is_null());
- vmo_page = allocate_physical_page();
+ vmo_page = allocate_physical_page(ShouldZeroFill::No);
if (vmo_page.is_null()) {
kprintf("MM: page_in_from_inode was unable to allocate a physical page\n");
return false;
@@ -371,7 +366,7 @@ PageFaultResponse MemoryManager::handle_page_fault(const PageFault& fault)
return PageFaultResponse::ShouldCrash;
}
-RetainPtr<PhysicalPage> MemoryManager::allocate_physical_page()
+RetainPtr<PhysicalPage> MemoryManager::allocate_physical_page(ShouldZeroFill should_zero_fill)
{
InterruptDisabler disabler;
if (1 > m_free_physical_pages.size())
@@ -379,7 +374,13 @@ RetainPtr<PhysicalPage> MemoryManager::allocate_physical_page()
#ifdef MM_DEBUG
dbgprintf("MM: allocate_physical_page vending P%x (%u remaining)\n", m_free_physical_pages.last()->paddr().get(), m_free_physical_pages.size());
#endif
- return m_free_physical_pages.take_last();
+ auto physical_page = m_free_physical_pages.take_last();
+ if (should_zero_fill == ShouldZeroFill::Yes) {
+ auto* ptr = (dword*)quickmap_page(*physical_page);
+ fast_dword_fill(ptr, 0, PAGE_SIZE / sizeof(dword));
+ unquickmap_page();
+ }
+ return physical_page;
}
RetainPtr<PhysicalPage> MemoryManager::allocate_supervisor_physical_page()
@@ -390,7 +391,9 @@ RetainPtr<PhysicalPage> MemoryManager::allocate_supervisor_physical_page()
#ifdef MM_DEBUG
dbgprintf("MM: allocate_supervisor_physical_page vending P%x (%u remaining)\n", m_free_supervisor_physical_pages.last()->paddr().get(), m_free_supervisor_physical_pages.size());
#endif
- return m_free_supervisor_physical_pages.take_last();
+ auto physical_page = m_free_supervisor_physical_pages.take_last();
+ fast_dword_fill((dword*)physical_page->paddr().as_ptr(), 0, PAGE_SIZE / sizeof(dword));
+ return physical_page;
}
void MemoryManager::enter_process_paging_scope(Process& process)
@@ -403,9 +406,10 @@ void MemoryManager::enter_process_paging_scope(Process& process)
void MemoryManager::flush_entire_tlb()
{
asm volatile(
- "mov %cr3, %eax\n"
- "mov %eax, %cr3\n"
- );
+ "mov %%cr3, %%eax\n"
+ "mov %%eax, %%cr3\n"
+ ::: "%eax", "memory"
+ );
}
void MemoryManager::flush_tlb(LinearAddress laddr)
@@ -416,11 +420,14 @@ void MemoryManager::flush_tlb(LinearAddress laddr)
byte* MemoryManager::quickmap_page(PhysicalPage& physical_page)
{
ASSERT_INTERRUPTS_DISABLED();
+ ASSERT(!m_quickmap_in_use);
+ m_quickmap_in_use = true;
auto page_laddr = m_quickmap_addr;
- auto pte = ensure_pte(current->page_directory(), page_laddr);
+ auto pte = ensure_pte(kernel_page_directory(), page_laddr);
pte.set_physical_page_base(physical_page.paddr().get());
pte.set_present(true);
pte.set_writable(true);
+ pte.set_user_allowed(false);
flush_tlb(page_laddr);
ASSERT((dword)pte.physical_page_base() == physical_page.paddr().get());
#ifdef MM_DEBUG
@@ -432,8 +439,9 @@ byte* MemoryManager::quickmap_page(PhysicalPage& physical_page)
void MemoryManager::unquickmap_page()
{
ASSERT_INTERRUPTS_DISABLED();
+ ASSERT(m_quickmap_in_use);
auto page_laddr = m_quickmap_addr;
- auto pte = ensure_pte(current->page_directory(), page_laddr);
+ auto pte = ensure_pte(kernel_page_directory(), page_laddr);
#ifdef MM_DEBUG
auto old_physical_address = pte.physical_page_base();
#endif
@@ -444,6 +452,7 @@ void MemoryManager::unquickmap_page()
#ifdef MM_DEBUG
dbgprintf("MM: >> unquickmap_page L%x =/> P%x\n", page_laddr, old_physical_address);
#endif
+ m_quickmap_in_use = false;
}
void MemoryManager::remap_region_page(Region& region, unsigned page_index_in_region, bool user_allowed)
@@ -463,7 +472,7 @@ void MemoryManager::remap_region_page(Region& region, unsigned page_index_in_reg
pte.set_user_allowed(user_allowed);
region.page_directory()->flush(page_laddr);
#ifdef MM_DEBUG
- dbgprintf("MM: >> remap_region_page (PD=%x, PTE=P%x) '%s' L%x => P%x (@%p)\n", region.page_directory()->cr3(), pte.ptr(), region.name.characters(), page_laddr.get(), physical_page->paddr().get(), physical_page.ptr());
+ dbgprintf("MM: >> remap_region_page (PD=%x, PTE=P%x) '%s' L%x => P%x (@%p)\n", region.page_directory()->cr3(), pte.ptr(), region.name().characters(), page_laddr.get(), physical_page->paddr().get(), physical_page.ptr());
#endif
}
@@ -501,7 +510,7 @@ void MemoryManager::map_region_at_address(PageDirectory& page_directory, Region&
pte.set_user_allowed(user_allowed);
page_directory.flush(page_laddr);
#ifdef MM_DEBUG
- dbgprintf("MM: >> map_region_at_address (PD=%x) '%s' L%x => P%x (@%p)\n", &page_directory, region.name.characters(), page_laddr, physical_page ? physical_page->paddr().get() : 0, physical_page.ptr());
+ dbgprintf("MM: >> map_region_at_address (PD=%x) '%s' L%x => P%x (@%p)\n", &page_directory, region.name().characters(), page_laddr, physical_page ? physical_page->paddr().get() : 0, physical_page.ptr());
#endif
}
}
@@ -713,12 +722,12 @@ int Region::commit()
{
InterruptDisabler disabler;
#ifdef MM_DEBUG
- dbgprintf("MM: commit %u pages in Region %p (VMO=%p) at L%x\n", vmo().page_count(), this, &vmo(), laddr.get());
+ dbgprintf("MM: commit %u pages in Region %p (VMO=%p) at L%x\n", vmo().page_count(), this, &vmo(), laddr().get());
#endif
for (size_t i = first_page_index(); i <= last_page_index(); ++i) {
if (!vmo().physical_pages()[i].is_null())
continue;
- auto physical_page = MM.allocate_physical_page();
+ auto physical_page = MM.allocate_physical_page(MemoryManager::ShouldZeroFill::Yes);
if (!physical_page) {
kprintf("MM: commit was unable to allocate a physical page\n");
return -ENOMEM;
diff --git a/Kernel/MemoryManager.h b/Kernel/MemoryManager.h
index bd80937848..a2db9221b9 100644
--- a/Kernel/MemoryManager.h
+++ b/Kernel/MemoryManager.h
@@ -217,7 +217,9 @@ public:
bool validate_user_read(const Process&, LinearAddress) const;
bool validate_user_write(const Process&, LinearAddress) const;
- RetainPtr<PhysicalPage> allocate_physical_page();
+ enum class ShouldZeroFill { No, Yes };
+
+ RetainPtr<PhysicalPage> allocate_physical_page(ShouldZeroFill);
RetainPtr<PhysicalPage> allocate_supervisor_physical_page();
void remap_region(Process&, Region&);
@@ -351,6 +353,7 @@ private:
HashTable<Region*> m_regions;
size_t m_ram_size { 0 };
+ bool m_quickmap_in_use { false };
};
struct ProcessPagingScope {
diff --git a/Kernel/i386.h b/Kernel/i386.h
index 0b7ff5dbeb..46645f2ca5 100644
--- a/Kernel/i386.h
+++ b/Kernel/i386.h
@@ -83,7 +83,14 @@ void write_gdt_entry(word selector, Descriptor&);
#define sti() asm volatile("sti")
#define memory_barrier() asm volatile ("" ::: "memory")
-static inline dword cpu_flags()
+inline dword cpu_cr3()
+{
+ dword cr3;
+ asm volatile("movl %%cr3, %%eax":"=a"(cr3));
+ return cr3;
+}
+
+inline dword cpu_flags()
{
dword flags;
asm volatile(
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-17 01:33:31 +0000