IMP: Basic ARM64 port.

20 files changed, 394 insertions, 212 deletions

diff --git a/dev/zka/HALKit/AMD64/HalACPIFactoryInterface.cxx b/dev/zka/HALKit/AMD64/HalACPIFactoryInterface.cxx
index 83f9993f..0d00b643 100644
--- a/dev/zka/HALKit/AMD64/HalACPIFactoryInterface.cxx
+++ b/dev/zka/HALKit/AMD64/HalACPIFactoryInterface.cxx
@@ -82,8 +82,8 @@ namespace Kernel
 		};
 	} // namespace Detail
 
-	ACPIFactoryInterface::ACPIFactoryInterface(VoidPtr rsdPtr)
-		: fRsdp(rsdPtr), fEntries(0)
+	ACPIFactoryInterface::ACPIFactoryInterface(VoidPtr rsp_ptr)
+		: fRsdp(rsp_ptr), fEntries(0)
 	{
 	}
 
@@ -123,86 +123,4 @@ namespace Kernel
 					 "jmp reset_wait ; "
 					 ".att_syntax; ");
 	}
-
-	/// @brief Finds a descriptor table inside ACPI XSDT.
-	ErrorOr<voidPtr> ACPIFactoryInterface::Find(const Char* signature)
-	{
-		MUST_PASS(fRsdp);
-
-		if (!signature)
-			return ErrorOr<voidPtr>{-1};
-
-		if (*signature == 0)
-			return ErrorOr<voidPtr>{-1};
-
-		RSDP* rsdPtr = reinterpret_cast<RSDP*>(this->fRsdp);
-
-		if (rsdPtr->Revision <= 1)
-			return ErrorOr<voidPtr>{-1};
-
-		RSDT* xsdt = reinterpret_cast<RSDT*>(rsdPtr->RsdtAddress);
-
-		Int64 num = (xsdt->Length - sizeof(SDT)) / sizeof(UInt32);
-
-		/***
-			crucial to avoid - overflows.
-			*/
-		if (num < 1)
-		{
-			/// stop here, we should have entries...
-			ke_stop(RUNTIME_CHECK_ACPI);
-			return ErrorOr<voidPtr>{-1};
-		}
-
-		this->fEntries = num;
-
-		kcout << "ACPI: Number of entries: " << number(this->fEntries) << endl;
-		kcout << "ACPI: Revision: " << number(xsdt->Revision) << endl;
-		kcout << "ACPI: Signature: " << xsdt->Signature << endl;
-		kcout << "ACPI: Address of XSDT: " << hex_number((UIntPtr)xsdt) << endl;
-
-		const short cAcpiSignatureLength = 4;
-
-		for (Size index = 0; index < this->fEntries; ++index)
-		{
-			SDT* sdt = reinterpret_cast<SDT*>(xsdt->AddressArr[index]);
-
-			kcout << "ACPI: Checksum: " << number(sdt->Checksum) << endl;
-			kcout << "ACPI: Revision: " << number(sdt->Revision) << endl;
-
-			for (short signature_index = 0; signature_index < cAcpiSignatureLength; ++signature_index)
-			{
-				if (sdt->Signature[signature_index] != signature[signature_index])
-					break;
-
-				if (signature_index == (cAcpiSignatureLength - 1))
-				{
-					kcout << "ACPI: Found the SDT. " << endl;
-					return ErrorOr<voidPtr>(reinterpret_cast<voidPtr>(xsdt->AddressArr[index]));
-				}
-			}
-		}
-
-		return ErrorOr<voidPtr>{-1};
-	}
-
-	/***
-	@brief check SDT header
-	@param checksum the header to checksum
-	@param len the length of it.
-*/
-	bool ACPIFactoryInterface::Checksum(const Char* checksum, SSizeT len)
-	{
-		if (len == 0)
-			return -1;
-
-		char chr = 0;
-
-		for (int index = 0; index < len; ++index)
-		{
-			chr += checksum[index];
-		}
-
-		return chr == 0;
-	}
 } // namespace Kernel
diff --git a/dev/zka/HALKit/AMD64/HalCoreInterruptHandlerAMD64.cxx b/dev/zka/HALKit/AMD64/HalCoreInterruptHandlerAMD64.cxx
index c6b8303d..1167e861 100644
--- a/dev/zka/HALKit/AMD64/HalCoreInterruptHandlerAMD64.cxx
+++ b/dev/zka/HALKit/AMD64/HalCoreInterruptHandlerAMD64.cxx
@@ -4,6 +4,7 @@
 
 ------------------------------------------- */
 
+#include "NewKit/Stop.hxx"
 #include <ArchKit/ArchKit.hxx>
 #include <KernelKit/UserProcessScheduler.hxx>
 #include <NewKit/String.hxx>
@@ -43,13 +44,9 @@ EXTERN_C void idt_handle_pf(Kernel::UIntPtr rsp)
 	Kernel::ke_stop(RUNTIME_CHECK_PROCESS);
 }
 
-EXTERN_C void idt_handle_scheduler(Kernel::UIntPtr rsp)
+/// @brief Handle scheduler interrupt.
+EXTERN_C void idt_handle_scheduler()
 {
-	if (Kernel::cProcessScheduler == nullptr)
-	{
-		Kernel::ke_stop(RUNTIME_CHECK_UNEXCPECTED);
-	}
-
 	Kernel::UserProcessHelper::StartScheduling();
 }
 
@@ -101,6 +98,8 @@ EXTERN_C void idt_handle_ud(Kernel::UIntPtr rsp)
 /// @return nothing.
 EXTERN_C Kernel::Void hal_system_call_enter(Kernel::UIntPtr rcx, Kernel::UIntPtr rdx)
 {
+    Kernel::HAL::Out8(0x20, 0x20); // Acknowledge interrupt to master PIC
+
 	if (rcx <= (kSyscalls.Count() - 1))
 	{
 		kcout << "syscall: Enter Fn.\r";
@@ -117,6 +116,8 @@ EXTERN_C Kernel::Void hal_system_call_enter(Kernel::UIntPtr rcx, Kernel::UIntPtr
 /// @return nothing.
 EXTERN_C Kernel::Void hal_kernel_call_enter(Kernel::UIntPtr rcx, Kernel::UIntPtr rdx, Kernel::UIntPtr r8, Kernel::UIntPtr r9)
 {
+    Kernel::HAL::Out8(0x20, 0x20); // Acknowledge interrupt to master PIC
+
 	if (rcx <= (kSyscalls.Count() - 1))
 	{
 		kcout << "kerncall: Enter Fn.\r";
diff --git a/dev/zka/HALKit/AMD64/HalCoreMPScheduler.cxx b/dev/zka/HALKit/AMD64/HalCoreMPScheduler.cxx
index ae6dc905..44f1f60a 100644
--- a/dev/zka/HALKit/AMD64/HalCoreMPScheduler.cxx
+++ b/dev/zka/HALKit/AMD64/HalCoreMPScheduler.cxx
@@ -136,15 +136,6 @@ namespace Kernel::HAL
 
 	EXTERN_C Bool mp_register_process(VoidPtr image, UInt8* stack_ptr, HAL::StackFramePtr stack_frame);
 
-	/// @brief Called when the AP is ready.
-	/// @internal
-	EXTERN_C Void hal_on_ap_startup(Void)
-	{
-		while (Yes)
-		{
-		}
-	}
-
 	struct PROCESS_CONTROL_BLOCK final
 	{
 		HAL::StackFramePtr f_Frame;
@@ -157,18 +148,17 @@ namespace Kernel::HAL
 		return fBlocks[UserProcessScheduler::The().CurrentProcess().Leak().ProcessId % kSchedProcessLimitPerTeam].f_Frame;
 	}
 
+	EXTERN_C Void mp_do_task_switch(VoidPtr image, UInt8* stack_ptr, HAL::StackFramePtr stack_frame);
+
 	EXTERN_C Bool mp_register_process(VoidPtr image, UInt8* stack_ptr, HAL::StackFramePtr stack_frame)
 	{
-		if (kSMPAware)
-		{
-			fBlocks[UserProcessScheduler::The().CurrentProcess().Leak().ProcessId % kSchedProcessLimitPerTeam].f_Frame = stack_frame;
-			fBlocks[UserProcessScheduler::The().CurrentProcess().Leak().ProcessId % kSchedProcessLimitPerTeam].f_Stack = stack_ptr;
-			fBlocks[UserProcessScheduler::The().CurrentProcess().Leak().ProcessId % kSchedProcessLimitPerTeam].f_Image = image;
+		fBlocks[UserProcessScheduler::The().CurrentProcess().Leak().ProcessId % kSchedProcessLimitPerTeam].f_Frame = stack_frame;
+		fBlocks[UserProcessScheduler::The().CurrentProcess().Leak().ProcessId % kSchedProcessLimitPerTeam].f_Stack = stack_ptr;
+		fBlocks[UserProcessScheduler::The().CurrentProcess().Leak().ProcessId % kSchedProcessLimitPerTeam].f_Image = image;
 
-			return Yes;
-		}
+		mp_do_task_switch(image, stack_ptr, stack_frame);
 
-		return No;
+		return Yes;
 	}
 
 	/***********************************************************************************/
diff --git a/dev/zka/HALKit/AMD64/HalDescriptorLoader.cxx b/dev/zka/HALKit/AMD64/HalDescriptorLoader.cxx
index 44263a1c..bc06d01a 100644
--- a/dev/zka/HALKit/AMD64/HalDescriptorLoader.cxx
+++ b/dev/zka/HALKit/AMD64/HalDescriptorLoader.cxx
@@ -5,6 +5,7 @@
 ------------------------------------------- */
 
 #include <ArchKit/ArchKit.hxx>
+#include <HALKit/AMD64/Processor.hxx>
 
 namespace Kernel::HAL
 {
@@ -15,24 +16,32 @@ namespace Kernel::HAL
 
 		STATIC Void hal_remap_intel_pic_ctrl(Void) noexcept
 		{
-			auto a1 = HAL::In8(0xa1); // save masks
-			auto a2 = HAL::In8(0xa2);
+			uint8_t a1_saved = In8(kPICData);
+			uint8_t a2_saved = In8(kPIC2Data);
 
-			HAL::Out8(0x20, 0x11);
+			Out8(kPICCommand, 0x11); // Start initialization
+			Out8(kPICData, 0x20);	 // Master PIC offset
+			Out8(kPICData, 0x04);	 // Tell master PIC there is a slave
+			Out8(kPICData, 0x01);	 // 8086 mode
 
-			HAL::Out8(0xA0, 0x11);
+			Out8(kPIC2Command, 0x11); // Start initialization
+			Out8(kPIC2Data, 0x28);	  // Slave PIC offset
+			Out8(kPIC2Data, 0x02);	  // Tell slave PIC its cascade
+			Out8(kPIC2Data, 0x01);	  // 8086 mode
 
-			HAL::Out8(0x21, 32);
-			HAL::Out8(0xA1, 40);
+			Out8(kPICData, a1_saved); // Restore saved masks
+			Out8(kPIC2Data, a2_saved);
+		}
 
-			HAL::Out8(0x21, 4);
-			HAL::Out8(0xA1, 2);
+		STATIC Void hal_enable_pit() noexcept
+		{
+			// Configure PIT to receieve scheduler interrupts.
 
-			HAL::Out8(0x21, 0x01);
-			HAL::Out8(0xA1, 0x01);
+			UInt32 cCommonDivisor = kPITFrequency / 100; // 100 Hz.
 
-			HAL::Out8(0x21, a2);
-			HAL::Out8(0xA1, a1);
+			HAL::Out8(kPITControlPort, 0x36);						  // Command to PIT
+			HAL::Out8(kPITChannel0Port, cCommonDivisor & 0xFF);		  // Send low byte
+			HAL::Out8(kPITControlPort, (cCommonDivisor >> 8) & 0xFF); // Send high byte
 		}
 	} // namespace Detail
 
@@ -46,6 +55,9 @@ namespace Kernel::HAL
 
 	Void IDTLoader::Load(Register64& idt)
 	{
+		Detail::hal_remap_intel_pic_ctrl();
+		Detail::hal_enable_pit();
+
 		volatile ::Kernel::UIntPtr** ptr_ivt = (volatile ::Kernel::UIntPtr**)idt.Base;
 
 		for (UInt16 idt_indx = 0; idt_indx < (kKernelIdtSize); ++idt_indx)
@@ -66,8 +78,6 @@ namespace Kernel::HAL
 					(kKernelIdtSize)-1;
 
 		hal_load_idt(idt);
-
-		Detail::hal_remap_intel_pic_ctrl();
 	}
 
 	void GDTLoader::Load(Ref<RegisterGDT>& gdt)
diff --git a/dev/zka/HALKit/AMD64/HalInterruptAPI.asm b/dev/zka/HALKit/AMD64/HalInterruptAPI.asm
index cdbb2d1f..d9e16f6c 100644
--- a/dev/zka/HALKit/AMD64/HalInterruptAPI.asm
+++ b/dev/zka/HALKit/AMD64/HalInterruptAPI.asm
@@ -131,8 +131,24 @@ IntNormal 28
 IntNormal 29
 IntExp    30
 IntNormal 31
-IntNormal 32
+
+[extern idt_handle_scheduler]
+
+__ZKA_INT_32:
+    cli
+
+    push rsp
+
+    jmp idt_handle_scheduler
+
+    add rsp, 16
+    pop rsp
+
+    sti
+    o64 iret
+
 IntNormal 33
+
 IntNormal 34
 IntNormal 35
 IntNormal 36
@@ -194,25 +210,7 @@ __ZKA_INT_51:
     std
     o64 iret
 
-[extern hal_on_ap_startup]
-
-PRESENT        equ 1 << 7
-NOT_SYS        equ 1 << 4
-EXEC           equ 1 << 3
-DC             equ 1 << 2
-RW             equ 1 << 1
-ACCESSED       equ 1 << 0
-
-; Flags bits
-GRAN_4K       equ 1 << 7
-SZ_32         equ 1 << 6
-LONG_MODE     equ 1 << 5
-
-__ZKA_INT_52:
-    cld
-    jmp hal_on_ap_startup
-    std
-    ret
+IntNormal 52
 
 IntNormal 53
 IntNormal 54
diff --git a/dev/zka/HALKit/AMD64/HalKernelMain.cxx b/dev/zka/HALKit/AMD64/HalKernelMain.cxx
index 30124932..ad32ada6 100644
--- a/dev/zka/HALKit/AMD64/HalKernelMain.cxx
+++ b/dev/zka/HALKit/AMD64/HalKernelMain.cxx
@@ -6,6 +6,7 @@
 
 #include <ArchKit/ArchKit.hxx>
 #include <KernelKit/UserProcessScheduler.hxx>
+#include <KernelKit/HardwareThreadScheduler.hxx>
 #include <KernelKit/CodeMgr.hxx>
 #include <modules/ACPI/ACPIFactoryInterface.hxx>
 #include <NetworkKit/IPC.hxx>
@@ -15,13 +16,14 @@
 namespace Kernel::HAL
 {
 	/// @brief Gets the system cores using the MADT.
-	/// @param rsdPtr The 'RSD PTR' data structure.
-	EXTERN void mp_get_cores(Kernel::voidPtr rsdPtr) noexcept;
+	/// @param rsp_ptr The 'RSD PTR' data structure.
+	EXTERN void mp_get_cores(Kernel::voidPtr rsp_ptr) noexcept;
 } // namespace Kernel::HAL
 
 namespace Kernel
 {
 	EXTERN UserProcessScheduler* cProcessScheduler;
+	EXTERN HardwareThreadScheduler* cHardwareThreadScheduler;
 }
 
 EXTERN_C Kernel::VoidPtr kInterruptVectorTable[];
@@ -35,6 +37,7 @@ EXTERN_C void hal_init_platform(
 	kHandoverHeader = HandoverHeader;
 
 	Kernel::cProcessScheduler = nullptr;
+	Kernel::cHardwareThreadScheduler = nullptr;
 
 	if (kHandoverHeader->f_Magic != kHandoverMagic &&
 		kHandoverHeader->f_Version != kHandoverVersion)
@@ -42,13 +45,18 @@ EXTERN_C void hal_init_platform(
 		return;
 	}
 
-	// get page size.
-	kKernelBitMpSize = kHandoverHeader->f_BitMapSize;
+	/************************************** */
+	/*     INITIALIZE BIT MAP.              */
+	/************************************** */
 
-	// get virtual address start (for the heap)
+	kKernelBitMpSize = kHandoverHeader->f_BitMapSize;
 	kKernelBitMpStart = reinterpret_cast<Kernel::VoidPtr>(
 		reinterpret_cast<Kernel::UIntPtr>(kHandoverHeader->f_BitMapStart));
 
+	/************************************** */
+	/*     INITIALIZE GDT AND SEGMENTS. */
+	/************************************** */
+
 	STATIC CONST auto cEntriesCount = 6;
 
 	/* GDT, mostly descriptors for user and kernel segments. */
@@ -61,25 +69,25 @@ EXTERN_C void hal_init_platform(
 	};
 
 	// Load memory descriptors.
-	Kernel::HAL::RegisterGDT gdtBase;
+	Kernel::HAL::RegisterGDT gdt_reg;
 
-	gdtBase.Base  = reinterpret_cast<Kernel::UIntPtr>(cGdt);
-	gdtBase.Limit = (sizeof(Kernel::HAL::Detail::ZKA_GDT_ENTRY) * cEntriesCount) - 1;
+	gdt_reg.Base  = reinterpret_cast<Kernel::UIntPtr>(cGdt);
+	gdt_reg.Limit = (sizeof(Kernel::HAL::Detail::ZKA_GDT_ENTRY) * cEntriesCount) - 1;
 
 	//! GDT will load hal_read_init after it successfully loads the segments.
-	Kernel::HAL::GDTLoader gdtLoader;
-	gdtLoader.Load(gdtBase);
+	Kernel::HAL::GDTLoader gdt_loader;
+	gdt_loader.Load(gdt_reg);
 
 	Kernel::ke_stop(RUNTIME_CHECK_BOOTSTRAP);
 }
 
 EXTERN_C Kernel::Void hal_real_init(Kernel::Void) noexcept
 {
-	Kernel::HAL::Register64 idtBase;
-	idtBase.Base = (Kernel::UIntPtr)kInterruptVectorTable;
+	Kernel::HAL::Register64 idt_reg;
+	idt_reg.Base = (Kernel::UIntPtr)kInterruptVectorTable;
 
-	Kernel::HAL::IDTLoader idtLoader;
-	idtLoader.Load(idtBase);
+	Kernel::HAL::IDTLoader idt_loader;
+	idt_loader.Load(idt_reg);
 
 	if (kHandoverHeader->f_HardwareTables.f_MultiProcessingEnabled)
 		Kernel::HAL::mp_get_cores(kHandoverHeader->f_HardwareTables.f_VendorPtr);
@@ -87,10 +95,7 @@ EXTERN_C Kernel::Void hal_real_init(Kernel::Void) noexcept
 	Kernel::NeFileSystemMgr* mgr = Kernel::mm_new_class<Kernel::NeFileSystemMgr>();
 	Kernel::NeFileSystemMgr::Mount(mgr);
 
-	Kernel::HAL::mm_map_page(mp_user_switch_proc, Kernel::HAL::eFlagsUser | Kernel::HAL::eFlagsWr | Kernel::HAL::eFlagsPresent);
-	Kernel::HAL::mm_map_page(mp_user_switch_proc_stack_begin, Kernel::HAL::eFlagsUser | Kernel::HAL::eFlagsWr | Kernel::HAL::eFlagsPresent);
-
-	mp_do_user_switch();
+	Kernel::UserProcessHelper::InitializeScheduling();
 
 	Kernel::ke_stop(RUNTIME_CHECK_BOOTSTRAP);
 }
diff --git a/dev/zka/HALKit/AMD64/HalMPContextSwitch.asm b/dev/zka/HALKit/AMD64/HalMPContextSwitch.asm
index c6480778..2ad38107 100644
--- a/dev/zka/HALKit/AMD64/HalMPContextSwitch.asm
+++ b/dev/zka/HALKit/AMD64/HalMPContextSwitch.asm
@@ -9,7 +9,7 @@
 
 [bits 64]
 
-[global mp_do_user_switch]
+[global mp_do_task_switch]
 [global mp_do_context_switch_pre]
 [global mp_user_switch_proc]
 [global mp_user_switch_proc_stack_begin]
@@ -17,12 +17,9 @@
 section .text
 
 ;; @brief Switch to user mode.
-mp_do_user_switch:
-    mov rbp, rsp
-    mov rsp, mp_user_switch_proc_stack_end
-
-    mov rdx, mp_user_switch_proc
-    invlpg [rdx]
+mp_do_task_switch:
+    mov rbp, rdx
+    mov rsp, rdx
 
     mov ax, 0x18 | 3
     mov ds, ax
@@ -32,15 +29,15 @@ mp_do_user_switch:
 
     push 0x18 | 3
 
-    mov rax, mp_user_switch_proc_stack_end
+    mov rax, rdx
     push rax
 
     o64 pushf
 
     push 0x20 | 3
 
-    mov rdx, mp_user_switch_proc
-    push rdx
+    mov rax, rcx
+    push rax
 
     o64 iret
 
diff --git a/dev/zka/HALKit/AMD64/HalPagingMgr.cxx b/dev/zka/HALKit/AMD64/HalPagingMgr.cxx
index 06a8b7d2..78978bc7 100644
--- a/dev/zka/HALKit/AMD64/HalPagingMgr.cxx
+++ b/dev/zka/HALKit/AMD64/HalPagingMgr.cxx
@@ -57,7 +57,7 @@ namespace Kernel::HAL
 		kcout << (pte->User ? "User" : "Not User") << endl;
 	}
 
-	STATIC Int32 mmi_map_page_table_entry(VoidPtr virtual_address, UInt32 flags, ZKA_PTE* pt_entry);
+	STATIC Int32 mmi_map_page_table_entry(VoidPtr virtual_address, UInt32 flags, PTE* pt_entry);
 
 	/// @brief Maps or allocates a page from virtual_address.
 	/// @param virtual_address a valid virtual address.
@@ -121,7 +121,7 @@ namespace Kernel::HAL
 
 	/// @brief Maps flags for a specific pte.
 	/// @internal Internal function.
-	STATIC Int32 mmi_map_page_table_entry(VoidPtr virtual_address, UInt32 flags, ZKA_PTE* pt_entry)
+	STATIC Int32 mmi_map_page_table_entry(VoidPtr virtual_address, UInt32 flags, PTE* pt_entry)
 	{
 		if (flags & ~eFlagsPresent)
 			pt_entry->Present = false;
diff --git a/dev/zka/HALKit/AMD64/HalSchedulerCore.cxx b/dev/zka/HALKit/AMD64/HalSchedulerCore.cxx
index 9dcce147..d2f678e2 100644
--- a/dev/zka/HALKit/AMD64/HalSchedulerCore.cxx
+++ b/dev/zka/HALKit/AMD64/HalSchedulerCore.cxx
@@ -26,7 +26,7 @@ namespace Kernel
 
 	EXTERN_C Void __zka_pure_call(void)
 	{
-		asm volatile("mov %r8, 0; mov %r9, 1; syscall");
+		UserProcessScheduler::The().CurrentProcess().Leak().Crash();
 	}
 
 	Bool hal_check_stack(HAL::StackFramePtr stack_ptr)
diff --git a/dev/zka/HALKit/AMD64/HalUtils.asm b/dev/zka/HALKit/AMD64/HalUtils.asm
index 0e4caf2b..715859e8 100644
--- a/dev/zka/HALKit/AMD64/HalUtils.asm
+++ b/dev/zka/HALKit/AMD64/HalUtils.asm
@@ -25,9 +25,3 @@ rt_install_tib:
 
 [extern cBspDone]
 [extern kApicMadtAddressesCount]
-[extern hal_on_ap_startup]
-[global hal_ap_trampoline]
-
-hal_ap_trampoline:
-hal_ap_trampoline_1:
-    jmp    hal_on_ap_startup
diff --git a/dev/zka/HALKit/AMD64/Processor.hxx b/dev/zka/HALKit/AMD64/Processor.hxx
index b0a8aa0a..f01c73ab 100644
--- a/dev/zka/HALKit/AMD64/Processor.hxx
+++ b/dev/zka/HALKit/AMD64/Processor.hxx
@@ -19,6 +19,15 @@
 #include <FirmwareKit/Handover.hxx>
 #include <HALKit/AMD64/Paging.hxx>
 
+#define kPITControlPort	 0x43
+#define kPITChannel0Port 0x40
+#define kPITFrequency	 1193180
+
+#define kPICCommand 0x20
+#define kPICData    0x21
+#define kPIC2Command 0xA0
+#define kPIC2Data    0xA1
+
 EXTERN_C
 {
 #include <cpuid.h>
@@ -35,7 +44,7 @@ EXTERN_C
 #define IsActiveLow(FLG)	  (FLG & 2)
 #define IsLevelTriggered(FLG) (FLG & 8)
 
-#define kInterruptGate (0x8E)
+#define kInterruptGate (0x0E)
 #define kTrapGate	   (0xEF)
 #define kTaskGate	   (0b10001100)
 #define kIDTSelector   (0x08)
@@ -59,7 +68,7 @@ namespace Kernel
 
 namespace Kernel::HAL
 {
-	/// @brief Virtual memory flags.
+	/// @brief Memory Manager mapping flags.
 	enum
 	{
 		eFlagsPresent = 1 << 0,
@@ -168,7 +177,7 @@ namespace Kernel::HAL
 		static Void Load(Ref<Register64>& idt);
 	};
 
-	Void mp_get_cores(VoidPtr rsdPtr) noexcept;
+	Void mp_get_cores(VoidPtr rsp_ptr) noexcept;
 	Void hal_send_start_ipi(UInt32 apicId, UInt8 vector, UInt32 targetAddress);
 	Void hal_send_end_ipi(UInt32 apicId, UInt8 vector, UInt32 targetAddress);
 
diff --git a/dev/zka/HALKit/ARM64/APM/APM.cxx b/dev/zka/HALKit/ARM64/APM/APM.cxx
new file mode 100644
index 00000000..7962aa16
--- /dev/null
+++ b/dev/zka/HALKit/ARM64/APM/APM.cxx
@@ -0,0 +1,37 @@
+/* -------------------------------------------
+
+	Copyright ZKA Technologies.
+
+------------------------------------------- */
+
+#include <modules/APM/APM.hxx>
+#include <KernelKit/LPC.hxx>
+
+using namespace Kernel;
+
+/// @brief Send a APM command into it's own IO space.
+/// @param base_dma the IO base port.
+/// @param cmd the command.
+/// @return status code.
+EXTERN_C Int32 apm_send_io_command(UInt16 cmd, APMPowerCmd value)
+{
+	switch (cmd)
+	{
+	case kAPMPowerCommandReboot: {
+		asm volatile(
+			"ldr x0, =0x84000009\n"
+			"hvc #0\n");
+
+		return kErrorSuccess;
+	}
+	case kAPMPowerCommandShutdown: {
+		asm volatile(
+			"ldr x0, =0x84000008\n"
+			"hvc #0\n");
+
+		return kErrorSuccess;
+	}
+	default:
+		return kErrorInvalidData;
+	}
+}
diff --git a/dev/zka/HALKit/ARM64/HalACPIFactoryInterface.cxx b/dev/zka/HALKit/ARM64/HalACPIFactoryInterface.cxx
new file mode 100644
index 00000000..75ecefee
--- /dev/null
+++ b/dev/zka/HALKit/ARM64/HalACPIFactoryInterface.cxx
@@ -0,0 +1,31 @@
+/* -------------------------------------------
+
+	Copyright ZKA Technologies.
+
+------------------------------------------- */
+
+#include <modules/ACPI/ACPIFactoryInterface.hxx>
+#include <NewKit/String.hxx>
+#include <ArchKit/ArchKit.hxx>
+#include <KernelKit/Heap.hxx>
+#include <modules/APM/APM.hxx>
+
+namespace Kernel
+{
+	ACPIFactoryInterface::ACPIFactoryInterface(VoidPtr rsp_ptr)
+		: fRsdp(rsp_ptr), fEntries(0)
+	{
+	}
+
+	Void ACPIFactoryInterface::Shutdown()
+	{
+		apm_send_io_command(kAPMPowerCommandShutdown, 0);
+	}
+
+	/// @brief Reboot machine in either ACPI or by triple faulting.
+	/// @return nothing it's a reboot.
+	Void ACPIFactoryInterface::Reboot()
+	{
+		apm_send_io_command(kAPMPowerCommandReboot, 0);
+	}
+} // namespace Kernel
diff --git a/dev/zka/HALKit/ARM64/HalCoreMPScheduler.cxx b/dev/zka/HALKit/ARM64/HalCoreMPScheduler.cxx
new file mode 100644
index 00000000..102ca194
--- /dev/null
+++ b/dev/zka/HALKit/ARM64/HalCoreMPScheduler.cxx
@@ -0,0 +1,19 @@
+/* -------------------------------------------
+
+	Copyright ZKA Technologies.
+
+------------------------------------------- */
+
+#include <modules/ACPI/ACPIFactoryInterface.hxx>
+#include <KernelKit/UserProcessScheduler.hxx>
+
+using namespace Kernel;
+
+EXTERN_C Void mp_do_task_switch(VoidPtr image, UInt8* stack_ptr, HAL::StackFramePtr stack_frame);
+
+EXTERN_C Bool mp_register_process(VoidPtr image, UInt8* stack_ptr, HAL::StackFramePtr stack_frame)
+{
+	mp_do_task_switch(image, stack_ptr, stack_frame);
+
+	return Yes;
+}
diff --git a/dev/zka/HALKit/ARM64/HalDebugOutput.cxx b/dev/zka/HALKit/ARM64/HalDebugOutput.cxx
new file mode 100644
index 00000000..9dc7278c
--- /dev/null
+++ b/dev/zka/HALKit/ARM64/HalDebugOutput.cxx
@@ -0,0 +1,81 @@
+/* -------------------------------------------
+
+	Copyright ZKA Technologies.
+
+------------------------------------------- */
+
+#include <ArchKit/ArchKit.hxx>
+#include <KernelKit/DebugOutput.hxx>
+#include <NewKit/Utils.hxx>
+#include <NewKit/New.hxx>
+
+namespace Kernel
+{
+	EXTERN_C void ke_io_write(const Char* bytes)
+	{
+#ifdef __DEBUG__
+		if (*bytes == 0)
+			return;
+
+		SizeT index = 0;
+		SizeT len	= 0;
+
+		index = 0;
+		len	  = rt_string_len(bytes, 255);
+
+		volatile UInt8* uart_ptr = (UInt8*)0x09000000;
+
+		while (index < len)
+		{
+			if (bytes[index] == '\r')
+				*uart_ptr = '\r';
+
+			*uart_ptr = bytes[index] == '\r' ? '\n' : bytes[index];
+			++index;
+		}
+#endif // __DEBUG__
+	}
+
+	EXTERN_C void ke_io_read(const Char* bytes)
+	{
+#ifdef __DEBUG__
+		SizeT index = 0;
+
+		volatile UInt8* uart_ptr = (UInt8*)0x09000000;
+
+		///! TODO: Look on how to wait for the UART to complete.
+		while (Yes)
+		{
+			auto in = *uart_ptr;
+
+			///! If enter pressed then break.
+			if (in == 0xD)
+			{
+				break;
+			}
+
+			if (in < '0' || in < 'A' || in < 'a')
+			{
+				if (in != '@' || in != '!' || in != '?' || in != '.' || in != '/' ||
+					in != ':')
+				{
+					continue;
+				}
+			}
+
+			((char*)bytes)[index] = in;
+
+			++index;
+		}
+
+		((char*)bytes)[index] = 0;
+#endif // __DEBUG__
+	}
+
+	TerminalDevice TerminalDevice::The() noexcept
+	{
+		TerminalDevice out(Kernel::ke_io_write, Kernel::ke_io_read);
+		return out;
+	}
+
+} // namespace Kernel
diff --git a/dev/zka/HALKit/ARM64/HalKernelMain.cxx b/dev/zka/HALKit/ARM64/HalKernelMain.cxx
index 56287733..4d0d0875 100644
--- a/dev/zka/HALKit/ARM64/HalKernelMain.cxx
+++ b/dev/zka/HALKit/ARM64/HalKernelMain.cxx
@@ -17,13 +17,6 @@
 #include <NetworkKit/IPC.hxx>
 #include <CFKit/Property.hxx>
 
-namespace Kernel::HAL
-{
-	/// @brief Gets the system cores using the MADT.
-	/// @param rsdPtr The 'RSD PTR' data structure.
-	EXTERN void mp_get_cores(Kernel::voidPtr rsdPtr) noexcept;
-} // namespace Kernel::HAL
-
 Kernel::Void hal_real_init(Kernel::Void) noexcept;
 EXTERN_C Kernel::Void ke_dll_entrypoint(Kernel::Void);
 
@@ -38,24 +31,5 @@ EXTERN_C void hal_init_platform(
 		return;
 	}
 
-	// get page size.
-	kKernelBitMpSize = kHandoverHeader->f_BitMapSize;
-
-	// get virtual address start (for the heap)
-	kKernelBitMpStart = reinterpret_cast<Kernel::VoidPtr>(
-		reinterpret_cast<Kernel::UIntPtr>(kHandoverHeader->f_BitMapStart));
-
-	if (kHandoverHeader->f_HardwareTables.f_MultiProcessingEnabled)
-		Kernel::HAL::mp_get_cores(kHandoverHeader->f_HardwareTables.f_VendorPtr);
-
-	kcout << "Creating filesystem and such.\r";
-
-	if (kHandoverHeader->f_HardwareTables.f_MultiProcessingEnabled)
-		Kernel::HAL::mp_get_cores(kHandoverHeader->f_HardwareTables.f_VendorPtr);
-
-	Kernel::NeFileSystemMgr::Mount(Kernel::mm_new_class<Kernel::NeFileSystemMgr>());
-
-	mp_do_user_switch();
-
-	Kernel::ke_stop(RUNTIME_CHECK_FAILED);
+	while (Yes) {}
 }
diff --git a/dev/zka/HALKit/ARM64/HalPagingMgr.cxx b/dev/zka/HALKit/ARM64/HalPagingMgr.cxx
new file mode 100644
index 00000000..7e686905
--- /dev/null
+++ b/dev/zka/HALKit/ARM64/HalPagingMgr.cxx
@@ -0,0 +1,87 @@
+/* -------------------------------------------
+
+	Copyright ZKA Technologies.
+
+	File: HalPagingMgr.cxx
+	Purpose: Platform Paging Manager..
+
+------------------------------------------- */
+
+#include <HALKit/ARM64/Paging.hxx>
+#include <HALKit/ARM64/Processor.hxx>
+
+namespace Kernel::HAL
+{
+	typedef UInt32 PageTableIndex;
+
+	/// \brief Page store type.
+	struct ZKA_PAGE_STORE final
+	{
+		struct
+		{
+			PDE*	fPde{nullptr};
+			PTE*	fPte{nullptr};
+			VoidPtr fVAddr{nullptr};
+		} fInternalStore;
+
+		Bool fStoreOp{No}; // Store operation in progress.
+
+		static ZKA_PAGE_STORE& The()
+		{
+			static ZKA_PAGE_STORE the;
+			return the;
+		}
+	};
+
+	/// \brief Retrieve the page status of a PTE.
+	STATIC Void mmi_page_status(PTE* pte)
+	{
+
+	}
+
+	STATIC Int32 mmi_map_page_table_entry(VoidPtr virtual_address, UInt32 flags, PTE* pt_entry);
+
+	/// @brief Maps or allocates a page from virtual_address.
+	/// @param virtual_address a valid virtual address.
+	/// @param phys_addr point to physical address.
+	/// @param flags the flags to put on the page.
+	/// @return Status code of page manipulation process.
+	EXTERN_C Int32 mm_map_page(VoidPtr virtual_address, UInt32 flags)
+	{
+		if (!virtual_address ||
+			!flags)
+			return 0;
+
+		ZKA_PAGE_STORE& page_store = ZKA_PAGE_STORE::The();
+
+		while (page_store.fStoreOp)
+			;
+
+		page_store.fStoreOp = Yes;
+
+		if (page_store.fInternalStore.fVAddr == virtual_address)
+		{
+			page_store.fStoreOp = No;
+			return mmi_map_page_table_entry(page_store.fInternalStore.fVAddr, flags, page_store.fInternalStore.fPte);
+		}
+
+		return -1;
+	}
+
+	/// @brief Maps flags for a specific pte.
+	/// @internal Internal function.
+	STATIC Int32 mmi_map_page_table_entry(VoidPtr virtual_address, UInt32 flags, PTE* pt_entry)
+	{
+		ZKA_PAGE_STORE& page_store = ZKA_PAGE_STORE::The();
+
+		// Update Internal store.
+
+		page_store.fInternalStore.fPde	 = nullptr;
+		page_store.fInternalStore.fPte	 = pt_entry;
+		page_store.fInternalStore.fVAddr = virtual_address;
+
+		page_store.fStoreOp = No;
+
+		return 0;
+	}
+} // namespace Kernel::HAL
diff --git a/dev/zka/HALKit/ARM64/HalSchedulerCore.cxx b/dev/zka/HALKit/ARM64/HalSchedulerCore.cxx
index 630df4fd..30e2f1b5 100644
--- a/dev/zka/HALKit/ARM64/HalSchedulerCore.cxx
+++ b/dev/zka/HALKit/ARM64/HalSchedulerCore.cxx
@@ -8,6 +8,11 @@
 
 namespace Kernel
 {
+   	EXTERN_C Void __zka_pure_call(void)
+	{
+	    UserProcessScheduler::The().CurrentProcess().Leak().Crash();
+	}
+
 	Void UserProcess::SetImageStart(VoidPtr image_start) noexcept
 	{
 		if (image_start == 0)
diff --git a/dev/zka/HALKit/ARM64/Processor.hxx b/dev/zka/HALKit/ARM64/Processor.hxx
index 533457a9..68c305f3 100644
--- a/dev/zka/HALKit/ARM64/Processor.hxx
+++ b/dev/zka/HALKit/ARM64/Processor.hxx
@@ -11,8 +11,6 @@
 #include <NewKit/Utils.hxx>
 #include <FirmwareKit/Handover.hxx>
 
-#define kPageSize 512 /* 64-bit PT */
-
 #define kCPUBackendName "ARMv8"
 
 namespace Kernel::HAL
@@ -23,6 +21,23 @@ namespace Kernel::HAL
 		UIntPtr Base;
 	};
 
+	/// @brief Memory Manager mapping flags.
+	enum
+	{
+		eFlagsPresent = 1 << 0,
+		eFlagsWr	  = 1 << 1,
+		eFlagsUser	  = 1 << 2,
+		eFlagsNX	  = 1 << 3,
+		eFlagsCount	  = 3,
+	};
+
+	/// @brief Set a PTE from pd_base.
+	/// @param virt_addr a valid virtual address.
+	/// @param phys_addr point to physical address.
+	/// @param flags the flags to put on the page.
+	/// @return Status code of page manip.
+	EXTERN_C Int32 mm_map_page(VoidPtr virt_addr, UInt32 flags);
+
 	typedef UIntPtr	   Reg;
 	typedef Register64 Register;
 
@@ -37,9 +52,20 @@ namespace Kernel::HAL
 		Reg R13{0};
 		Reg R14{0};
 		Reg R15{0};
+		Reg SP{0};
+		Reg BP{0};
 	};
 
 	typedef StackFrame* StackFramePtr;
+
+	inline Void rt_halt()
+	{
+		while (Yes)
+		{
+
+		}
+	}
+
 } // namespace Kernel::HAL
 
 inline Kernel::VoidPtr kKernelBitMpStart = nullptr;
diff --git a/dev/zka/HALKit/POWER/HalContextSwitchPowerPC.s b/dev/zka/HALKit/POWER/HalContextSwitchPowerPC.s
index 588de23a..d90c1fa0 100644
--- a/dev/zka/HALKit/POWER/HalContextSwitchPowerPC.s
+++ b/dev/zka/HALKit/POWER/HalContextSwitchPowerPC.s
@@ -7,10 +7,10 @@
 .align 4
 .type name, @function
 .text
-.globl mp_do_user_switch
+.globl mp_do_task_switch
 
 /* r3 (3) = assigner stack, r4 (4) = assignee stack */
-mp_do_user_switch:
+mp_do_task_switch:
     lwz 0(%4), 0(%3)
     lwz 4(%4), 4(%3)
     lwz 8(%4), 8(%3)