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Diffstat (limited to 'Kernel')
-rw-r--r--Kernel/Arch/i386/Boot/boot.S100
-rw-r--r--Kernel/VM/MemoryManager.cpp70
-rw-r--r--Kernel/VM/MemoryManager.h2
3 files changed, 74 insertions, 98 deletions
diff --git a/Kernel/Arch/i386/Boot/boot.S b/Kernel/Arch/i386/Boot/boot.S
index 7646585453..9289cb5a5f 100644
--- a/Kernel/Arch/i386/Boot/boot.S
+++ b/Kernel/Arch/i386/Boot/boot.S
@@ -42,8 +42,14 @@ boot_pd0:
.global boot_pd3
boot_pd3:
.skip 4096
-.global boot_pd3_pde1023_pt
-boot_pd3_pde1023_pt:
+.global boot_pd0_pt0
+boot_pd0_pt0:
+.skip 4096 * 4
+.global boot_pd3_pts
+boot_pd3_pts:
+.skip 4096 * 4
+.global boot_pd3_pt1023
+boot_pd3_pt1023:
.skip 4096
.section .text
@@ -69,18 +75,18 @@ pdpt
boot_pd0 : 512 pde's
- 0: (0-2MB) (id 2MB page)
- 1: (2-4MB) (id 2MB page)
- 2: (4-6MB) (id 2MB page)
- 3: (6-8MB) (id 2MB page)
+ 0: boot_pd0_pt0 (0-2MB) (id 512 4KB pages)
boot_pd3 : 512 pde's
- 0: boot_pd3_pde0 (3072-3074MB) (pseudo)
- 1: boot_pd3_pde1 (3074-3076MB) (pseudo)
- 2: boot_pd3_pde2 (3076-3078MB) (pseudo)
- 3: boot_pd3_pde3 (3078-3080MB) (pseudo)
- 4: boot_pd3_pde1023_pt (4094-4096MB) (for page table mappings)
+ 0: boot_pd3_pts[0] (3072-3074MB) (pseudo 512 4KB pages)
+ 1: boot_pd3_pts[1] (3074-3076MB) (pseudo 512 4KB pages)
+ 2: boot_pd3_pts[2] (3076-3078MB) (pseudo 512 4KB pages)
+ 3: boot_pd3_pts[3] (3078-3080MB) (pseudo 512 4KB pages)
+ 4: boot_pd3_pt1023 (4094-4096MB) (for page table mappings)
+
+the 9 page tables each contain 512 pte's that map individual 4KB pages
+
*/
start:
@@ -104,41 +110,74 @@ start:
xorl %eax, %eax
rep stosl
- /* identity map bottom 8MB using 2MB pages (only PDE, no PTE) */
- movl $4, %ecx
+ /* clear pd3 */
+ movl $(boot_pd3 - 0xc0000000), %edi
+ movl $1024, %ecx
+ xorl %eax, %eax
+ rep stosl
+
+ /* clear pd0's pt's */
+ movl $(boot_pd0_pt0 - 0xc0000000), %edi
+ movl $(1024 * 4), %ecx
xorl %eax, %eax
+ rep stosl
+
+ /* clear pd3's pt's */
+ movl $(boot_pd3_pts - 0xc0000000), %edi
+ movl $(1024 * 5), %ecx
+ xorl %eax, %eax
+ rep stosl
+
+ /* add boot_pd0_pt0 to boot_pd0 */
movl $(boot_pd0 - 0xc0000000), %edi
-1:
+ movl $(boot_pd0_pt0 - 0xc0000000), %eax
movl %eax, 0(%edi)
- /* PS(2MB) + R/W + Present */
- orl $0x83, 0(%edi)
+ /* R/W + Present */
+ orl $0x3, 0(%edi)
+
+ /* add boot_pd3_pts to boot_pd3 */
+ movl $4, %ecx
+ movl $(boot_pd3 - 0xc0000000), %edi
+ movl $(boot_pd3_pts - 0xc0000000), %eax
+1:
+ movl %eax, 0(%edi)
+ /* R/W + Present */
+ orl $0x3, 0(%edi)
addl $8, %edi
- addl $(1048576 * 2), %eax
+ addl $4096, %eax
loop 1b
- /* clear pd3 */
- movl $(boot_pd3 - 0xc0000000), %edi
- movl $1024, %ecx
+ /* identity map the 0 to 2MB range */
+ movl $512, %ecx
+ movl $(boot_pd0_pt0 - 0xc0000000), %edi
+ /*movl $0x100000, %eax*/
xorl %eax, %eax
- rep stosl
- /* pseudo-identity map first 8MB above 3GB mark using 2MB pages again */
- movl $4, %ecx
- xorl %eax, %eax
- movl $(boot_pd3 - 0xc0000000), %edi
1:
movl %eax, 0(%edi)
- /* PS(2MB) + R/W + Present */
- orl $0x83, 0(%edi)
+ /* R/W + Present */
+ orl $0x3, 0(%edi)
+ addl $8, %edi
+ addl $4096, %eax
+ loop 1b
+
+ /* pseudo identity map the 3072-3080MB range */
+ movl $(512 * 4), %ecx
+ movl $(boot_pd3_pts - 0xc0000000), %edi
+ xorl %eax, %eax
+1:
+ movl %eax, 0(%edi)
+ /* R/W + Present */
+ orl $0x3, 0(%edi)
addl $8, %edi
- addl $(1048576 * 2), %eax
+ addl $4096, %eax
loop 1b
/* create an empty page table for the top 2MB at the 4GB mark */
movl $(boot_pd3 - 0xc0000000), %edi
- movl $(boot_pd3_pde1023_pt - 0xc0000000), 4088(%edi)
+ movl $(boot_pd3_pt1023 - 0xc0000000), 4088(%edi)
orl $0x3, 4088(%edi)
movl $0, 4092(%edi)
@@ -158,10 +197,9 @@ start:
/* jmp to an address above the 3GB mark */
push %cs
- push $1f
+ push $1f
retf
1:
-
movl %cr3, %eax
movl %eax, %cr3
diff --git a/Kernel/VM/MemoryManager.cpp b/Kernel/VM/MemoryManager.cpp
index 29936251d6..2611f63d4e 100644
--- a/Kernel/VM/MemoryManager.cpp
+++ b/Kernel/VM/MemoryManager.cpp
@@ -62,8 +62,6 @@ MemoryManager::MemoryManager()
m_kernel_page_directory = PageDirectory::create_kernel_page_directory();
parse_memory_map();
write_cr3(kernel_page_directory().cr3());
- setup_low_identity_mapping();
- setup_low_pseudo_identity_mapping();
protect_kernel_image();
m_shared_zero_page = allocate_user_physical_page();
@@ -73,36 +71,6 @@ MemoryManager::~MemoryManager()
{
}
-void MemoryManager::setup_low_pseudo_identity_mapping()
-{
- // This code switches the pseudo-identity mapping (8 first MB above 3G mark) from 2MB pages to 4KB pages.
- // The boot code sets it up as 2MB huge pages for convenience. But we need 4KB pages to be able to protect
- // the kernel soon!
-
- for (size_t i = 0; i < 4; ++i) {
- m_low_pseudo_identity_mapping_pages[i] = allocate_supervisor_physical_page();
- FlatPtr base = i * (2 * MB);
- auto* page_table = (PageTableEntry*)quickmap_page(*m_low_pseudo_identity_mapping_pages[i]);
- for (size_t j = 0; j < 512; ++j) {
- auto& pte = page_table[j];
- pte.set_physical_page_base(base + j * PAGE_SIZE);
- pte.set_writable(true);
- pte.set_present(true);
- pte.set_execute_disabled(false);
- pte.set_user_allowed(false);
- }
- unquickmap_page();
- }
-
- auto* pd = quickmap_pd(*m_kernel_page_directory, 3);
- for (size_t i = 0; i < 4; ++i) {
- pd[i].set_huge(false);
- pd[i].set_page_table_base(m_low_pseudo_identity_mapping_pages[i]->paddr().get());
- }
-
- flush_entire_tlb();
-}
-
void MemoryManager::protect_kernel_image()
{
// Disable writing to the kernel text and rodata segments.
@@ -120,34 +88,6 @@ void MemoryManager::protect_kernel_image()
}
}
-void MemoryManager::setup_low_identity_mapping()
-{
- m_low_page_table = allocate_user_physical_page(ShouldZeroFill::Yes);
-
- auto* pd_zero = quickmap_pd(kernel_page_directory(), 0);
- pd_zero[1].set_present(false);
- pd_zero[2].set_present(false);
- pd_zero[3].set_present(false);
-
- auto& pde_zero = pd_zero[0];
- pde_zero.set_page_table_base(m_low_page_table->paddr().get());
- pde_zero.set_present(true);
- pde_zero.set_huge(false);
- pde_zero.set_writable(true);
- pde_zero.set_user_allowed(false);
- if (g_cpu_supports_nx)
- pde_zero.set_execute_disabled(true);
-
- for (FlatPtr offset = (1 * MB); offset < (2 * MB); offset += PAGE_SIZE) {
- auto& page_table_page = m_low_page_table;
- auto& pte = quickmap_pt(page_table_page->paddr())[offset / PAGE_SIZE];
- pte.set_physical_page_base(offset);
- pte.set_user_allowed(false);
- pte.set_present(offset != 0);
- pte.set_writable(offset < (1 * MB));
- }
-}
-
void MemoryManager::parse_memory_map()
{
RefPtr<PhysicalRegion> region;
@@ -574,11 +514,11 @@ void MemoryManager::flush_tlb(VirtualAddress vaddr)
: "memory");
}
-extern "C" PageTableEntry boot_pd3_pde1023_pt[1024];
+extern "C" PageTableEntry boot_pd3_pt1023[1024];
PageDirectoryEntry* MemoryManager::quickmap_pd(PageDirectory& directory, size_t pdpt_index)
{
- auto& pte = boot_pd3_pde1023_pt[4];
+ auto& pte = boot_pd3_pt1023[4];
auto pd_paddr = directory.m_directory_pages[pdpt_index]->paddr();
if (pte.physical_page_base() != pd_paddr.as_ptr()) {
#ifdef MM_DEBUG
@@ -595,7 +535,7 @@ PageDirectoryEntry* MemoryManager::quickmap_pd(PageDirectory& directory, size_t
PageTableEntry* MemoryManager::quickmap_pt(PhysicalAddress pt_paddr)
{
- auto& pte = boot_pd3_pde1023_pt[8];
+ auto& pte = boot_pd3_pt1023[8];
if (pte.physical_page_base() != pt_paddr.as_ptr()) {
#ifdef MM_DEBUG
dbg() << "quickmap_pt: Mapping P" << (void*)pt_paddr.as_ptr() << " at 0xffe08000 in pte @ " << &pte;
@@ -615,7 +555,7 @@ u8* MemoryManager::quickmap_page(PhysicalPage& physical_page)
ASSERT(!m_quickmap_in_use);
m_quickmap_in_use = true;
- auto& pte = boot_pd3_pde1023_pt[0];
+ auto& pte = boot_pd3_pt1023[0];
if (pte.physical_page_base() != physical_page.paddr().as_ptr()) {
#ifdef MM_DEBUG
dbg() << "quickmap_page: Mapping P" << (void*)physical_page.paddr().as_ptr() << " at 0xffe00000 in pte @ " << &pte;
@@ -633,7 +573,7 @@ void MemoryManager::unquickmap_page()
{
ASSERT_INTERRUPTS_DISABLED();
ASSERT(m_quickmap_in_use);
- auto& pte = boot_pd3_pde1023_pt[0];
+ auto& pte = boot_pd3_pt1023[0];
pte.clear();
flush_tlb(VirtualAddress(0xffe00000));
m_quickmap_in_use = false;
diff --git a/Kernel/VM/MemoryManager.h b/Kernel/VM/MemoryManager.h
index f4293fff35..35c954df5b 100644
--- a/Kernel/VM/MemoryManager.h
+++ b/Kernel/VM/MemoryManager.h
@@ -160,8 +160,6 @@ private:
void unregister_region(Region&);
void detect_cpu_features();
- void setup_low_identity_mapping();
- void setup_low_pseudo_identity_mapping();
void protect_kernel_image();
void parse_memory_map();
void flush_entire_tlb();
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 01:30:04 +0000