+/*
+ * AcessOS Microkernel Version
+ * proc.c
+ */
+#include <acess.h>
+#include <proc.h>
+#include <threads.h>
+#include <desctab.h>
+#include <mm_virt.h>
+#include <errno.h>
+#if USE_MP
+# include <mp.h>
+#endif
+
+// === FLAGS ===
+#define DEBUG_TRACE_SWITCH 0
+
+// === CONSTANTS ===
+#define SWITCH_MAGIC 0x55ECAFFF##FFFACE55 // There is no code in this area
+// Base is 1193182
+#define TIMER_DIVISOR 11931 //~100Hz
+
+// === IMPORTS ===
+extern tGDT gGDT[];
+extern void APStartup(); // 16-bit AP startup code
+extern Uint GetRIP(); // start.asm
+extern Uint64 gaInitPML4[512]; // start.asm
+extern void Kernel_Stack_Top;
+extern tSpinlock glThreadListLock;
+extern int giNumCPUs;
+extern int giNextTID;
+extern int giTotalTickets;
+extern int giNumActiveThreads;
+extern tThread gThreadZero;
+extern tThread *gActiveThreads;
+extern tThread *gSleepingThreads;
+extern tThread *gDeleteThreads;
+extern tThread *Threads_GetNextToRun(int CPU);
+extern void Threads_Dump();
+extern tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
+extern void Proc_AlterUserReturnAddr();
+
+// === PROTOTYPES ===
+void ArchThreads_Init();
+#if USE_MP
+void MP_StartAP(int CPU);
+void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode);
+#endif
+void Proc_Start();
+tThread *Proc_GetCurThread();
+void Proc_ChangeStack();
+ int Proc_Clone(Uint *Err, Uint Flags);
+void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
+void Proc_CallFaultHandler(tThread *Thread);
+void Proc_Scheduler();
+
+// === GLOBALS ===
+// --- Multiprocessing ---
+#if USE_MP
+volatile int giNumInitingCPUs = 0;
+tMPInfo *gMPFloatPtr = NULL;
+tAPIC *gpMP_LocalAPIC = NULL;
+Uint8 gaAPIC_to_CPU[256] = {0};
+tCPU gaCPUs[MAX_CPUS];
+#else
+tThread *gCurrentThread = NULL;
+#endif
+tTSS *gTSSs = NULL;
+tTSS gTSS0 = {0};
+// --- Error Recovery ---
+Uint32 gaDoubleFaultStack[1024];
+
+// === CODE ===
+/**
+ * \fn void ArchThreads_Init()
+ * \brief Starts the process scheduler
+ */
+void ArchThreads_Init()
+{
+ Uint pos = 0;
+
+ #if USE_MP
+ tMPTable *mptable;
+
+ // Mark BSP as active
+ gaCPUs[0].State = 2;
+
+ // -- Initialise Multiprocessing
+ // Find MP Floating Table
+ // - EBDA/Last 1Kib (640KiB)
+ for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
+ if( *(Uint*)(pos) == MPPTR_IDENT ) {
+ Log("Possible %p", pos);
+ if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
+ gMPFloatPtr = (void*)pos;
+ break;
+ }
+ }
+ // - Last KiB (512KiB base mem)
+ if(!gMPFloatPtr) {
+ for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
+ if( *(Uint*)(pos) == MPPTR_IDENT ) {
+ Log("Possible %p", pos);
+ if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
+ gMPFloatPtr = (void*)pos;
+ break;
+ }
+ }
+ }
+ // - BIOS ROM
+ if(!gMPFloatPtr) {
+ for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
+ if( *(Uint*)(pos) == MPPTR_IDENT ) {
+ Log("Possible %p", pos);
+ if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
+ gMPFloatPtr = (void*)pos;
+ break;
+ }
+ }
+ }
+
+ // If the MP Table Exists, parse it
+ if(gMPFloatPtr)
+ {
+ int i;
+ tMPTable_Ent *ents;
+ Log("gMPFloatPtr = %p", gMPFloatPtr);
+ Log("*gMPFloatPtr = {");
+ Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
+ Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
+ Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
+ Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
+ Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
+ Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
+ gMPFloatPtr->Features[0], gMPFloatPtr->Features[1],
+ gMPFloatPtr->Features[2], gMPFloatPtr->Features[3],
+ gMPFloatPtr->Features[4]
+ );
+ Log("}");
+
+ mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
+ Log("mptable = %p", mptable);
+ Log("*mptable = {");
+ Log("\t.Sig = 0x%08x", mptable->Sig);
+ Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
+ Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
+ Log("\t.Checksum = 0x%02x", mptable->Checksum);
+ Log("\t.OEMID = '%8c'", mptable->OemID);
+ Log("\t.ProductID = '%8c'", mptable->ProductID);
+ Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
+ Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
+ Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
+ Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
+ Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
+ Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
+ Log("}");
+
+ gpMP_LocalAPIC = (void*)MM_MapHWPage(mptable->LocalAPICMemMap, 1);
+
+ ents = mptable->Entries;
+ giNumCPUs = 0;
+
+ for( i = 0; i < mptable->EntryCount; i ++ )
+ {
+ int entSize = 0;
+ switch( ents->Type )
+ {
+ case 0: // Processor
+ entSize = 20;
+ Log("%i: Processor", i);
+ Log("\t.APICID = %i", ents->Proc.APICID);
+ Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
+ Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
+ Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
+ Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
+
+
+ if( !(ents->Proc.CPUFlags & 1) ) {
+ Log("DISABLED");
+ break;
+ }
+
+ // Check if there is too many processors
+ if(giNumCPUs >= MAX_CPUS) {
+ giNumCPUs ++; // If `giNumCPUs` > MAX_CPUS later, it will be clipped
+ break;
+ }
+
+ // Initialise CPU Info
+ gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
+ gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
+ gaCPUs[giNumCPUs].State = 0;
+ giNumCPUs ++;
+
+ // Send IPI
+ if( !(ents->Proc.CPUFlags & 2) )
+ {
+ MP_StartAP( giNumCPUs-1 );
+ }
+
+ break;
+ case 1: // Bus
+ entSize = 8;
+ Log("%i: Bus", i);
+ Log("\t.ID = %i", ents->Bus.ID);
+ Log("\t.TypeString = '%6c'", ents->Bus.TypeString);
+ break;
+ case 2: // I/O APIC
+ entSize = 8;
+ Log("%i: I/O APIC", i);
+ Log("\t.ID = %i", ents->IOAPIC.ID);
+ Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
+ Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
+ Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
+ break;
+ case 3: // I/O Interrupt Assignment
+ entSize = 8;
+ Log("%i: I/O Interrupt Assignment", i);
+ Log("\t.IntType = %i", ents->IOInt.IntType);
+ Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
+ Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
+ Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
+ Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
+ Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
+ break;
+ case 4: // Local Interrupt Assignment
+ entSize = 8;
+ Log("%i: Local Interrupt Assignment", i);
+ Log("\t.IntType = %i", ents->LocalInt.IntType);
+ Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
+ Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
+ Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
+ Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
+ Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
+ break;
+ default:
+ Log("%i: Unknown (%i)", i, ents->Type);
+ break;
+ }
+ ents = (void*)( (Uint)ents + entSize );
+ }
+
+ if( giNumCPUs > MAX_CPUS ) {
+ Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
+ giNumCPUs = MAX_CPUS;
+ }
+
+ while( giNumInitingCPUs )
+ MM_FinishVirtualInit();
+
+ Panic("Uh oh... MP Table Parsing is unimplemented\n");
+ }
+ else {
+ Log("No MP Table was found, assuming uniprocessor\n");
+ giNumCPUs = 1;
+ gTSSs = &gTSS0;
+ }
+ #else
+ giNumCPUs = 1;
+ gTSSs = &gTSS0;
+ MM_FinishVirtualInit();
+ #endif
+
+ #if USE_MP
+ // Initialise Normal TSS(s)
+ for(pos=0;pos<giNumCPUs;pos++)
+ {
+ #else
+ pos = 0;
+ #endif
+ gTSSs[pos].RSP0 = 0; // Set properly by scheduler
+ gGDT[6+pos*2].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
+ gGDT[6+pos*2].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
+ gGDT[6+pos*2].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
+ gGDT[6+pos*2+1].DWord[0] = ((Uint)(&gTSSs[pos])) >> 32;
+ #if USE_MP
+ }
+ for(pos=0;pos<giNumCPUs;pos++) {
+ #endif
+ __asm__ __volatile__ ("ltr %%ax"::"a"(0x30+pos*8));
+ #if USE_MP
+ }
+ #endif
+
+ #if USE_MP
+ gaCPUs[0].Current = &gThreadZero;
+ #else
+ gCurrentThread = &gThreadZero;
+ #endif
+
+ gThreadZero.MemState.CR3 = (Uint)gaInitPML4 - KERNEL_BASE;
+
+ // Set timer frequency
+ outb(0x43, 0x34); // Set Channel 0, Low/High, Rate Generator
+ outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
+ outb(0x40, (TIMER_DIVISOR>>8)&0xFF); // High Byte
+
+ // Create Per-Process Data Block
+ MM_Allocate(MM_PPD_CFG);
+
+ // Change Stacks
+ Proc_ChangeStack();
+}
+
+#if USE_MP
+void MP_StartAP(int CPU)
+{
+ Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
+ // Set location of AP startup code and mark for a warm restart
+ *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);
+ *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
+ outb(0x70, 0x0F); outb(0x71, 0x0A); // Warm Reset
+ MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);
+ giNumInitingCPUs ++;
+}
+
+void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
+{
+ Uint32 addr = (Uint)gpMP_LocalAPIC + 0x300;
+ Uint32 val;
+
+ // High
+ val = (Uint)APICID << 24;
+ Log("*%p = 0x%08x", addr+0x10, val);
+ *(Uint32*)(addr+0x10) = val;
+ // Low (and send)
+ val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
+ Log("*%p = 0x%08x", addr, val);
+ *(Uint32*)addr = val;
+}
+#endif
+
+/**
+ * \fn void Proc_Start()
+ * \brief Start process scheduler
+ */
+void Proc_Start()
+{
+ // Start Interrupts (and hence scheduler)
+ __asm__ __volatile__("sti");
+}
+
+/**
+ * \fn tThread *Proc_GetCurThread()
+ * \brief Gets the current thread
+ */
+tThread *Proc_GetCurThread()
+{
+ #if USE_MP
+ return gaCPUs[ gaAPIC_to_CPU[gpMP_LocalAPIC->ID.Val&0xFF] ].Current;
+ #else
+ return gCurrentThread;
+ #endif
+}
+
+/**
+ * \fn void Proc_ChangeStack()
+ * \brief Swaps the current stack for a new one (in the proper stack reigon)
+ */
+void Proc_ChangeStack()
+{
+ Uint rsp, rbp;
+ Uint tmp_rbp, old_rsp;
+ Uint curBase, newBase;
+
+ __asm__ __volatile__ ("mov %%rsp, %0":"=r"(rsp));
+ __asm__ __volatile__ ("mov %%rbp, %0":"=r"(rbp));
+
+ old_rsp = rsp;
+
+ // Create new KStack
+ newBase = MM_NewKStack();
+ // Check for errors
+ if(newBase == 0) {
+ Panic("What the?? Unable to allocate space for initial kernel stack");
+ return;
+ }
+
+ curBase = (Uint)&Kernel_Stack_Top;
+
+ LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
+
+ // Get ESP as a used size
+ rsp = curBase - rsp;
+ LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - rsp), (void*)(curBase - rsp), rsp );
+ // Copy used stack
+ memcpy( (void*)(newBase - rsp), (void*)(curBase - rsp), rsp );
+ // Get ESP as an offset in the new stack
+ rsp = newBase - rsp;
+ // Adjust EBP
+ rbp = newBase - (curBase - rbp);
+
+ // Repair EBPs & Stack Addresses
+ // Catches arguments also, but may trash stack-address-like values
+ for(tmp_rbp = rsp; tmp_rbp < newBase; tmp_rbp += 4)
+ {
+ if(old_rsp < *(Uint*)tmp_rbp && *(Uint*)tmp_rbp < curBase)
+ *(Uint*)tmp_rbp += newBase - curBase;
+ }
+
+ Proc_GetCurThread()->KernelStack = newBase;
+
+ __asm__ __volatile__ ("mov %0, %%rsp"::"r"(rsp));
+ __asm__ __volatile__ ("mov %0, %%rbp"::"r"(rbp));
+}
+
+/**
+ * \fn int Proc_Clone(Uint *Err, Uint Flags)
+ * \brief Clone the current process
+ */
+int Proc_Clone(Uint *Err, Uint Flags)
+{
+ tThread *newThread;
+ tThread *cur = Proc_GetCurThread();
+ Uint rip, rsp, rbp;
+
+ __asm__ __volatile__ ("mov %%rsp, %0": "=r"(rsp));
+ __asm__ __volatile__ ("mov %%rbp, %0": "=r"(rbp));
+
+ newThread = Threads_CloneTCB(Err, Flags);
+ if(!newThread) return -1;
+
+ // Initialise Memory Space (New Addr space or kernel stack)
+ if(Flags & CLONE_VM) {
+ newThread->MemState.CR3 = MM_Clone();
+ newThread->KernelStack = cur->KernelStack;
+ } else {
+ Uint tmp_rbp, old_rsp = rsp;
+
+ // Set CR3
+ newThread->MemState.CR3 = cur->MemState.CR3;
+
+ // Create new KStack
+ newThread->KernelStack = MM_NewKStack();
+ // Check for errors
+ if(newThread->KernelStack == 0) {
+ free(newThread);
+ return -1;
+ }
+
+ // Get ESP as a used size
+ rsp = cur->KernelStack - rsp;
+ // Copy used stack
+ memcpy(
+ (void*)(newThread->KernelStack - rsp),
+ (void*)(cur->KernelStack - rsp),
+ rsp
+ );
+ // Get ESP as an offset in the new stack
+ rsp = newThread->KernelStack - rsp;
+ // Adjust EBP
+ rbp = newThread->KernelStack - (cur->KernelStack - rbp);
+
+ // Repair EBPs & Stack Addresses
+ // Catches arguments also, but may trash stack-address-like values
+ for(tmp_rbp = rsp; tmp_rbp < newThread->KernelStack; tmp_rbp += 4)
+ {
+ if(old_rsp < *(Uint*)tmp_rbp && *(Uint*)tmp_rbp < cur->KernelStack)
+ *(Uint*)tmp_rbp += newThread->KernelStack - cur->KernelStack;
+ }
+ }
+
+ // Save core machine state
+ newThread->SavedState.RSP = rsp;
+ newThread->SavedState.RBP = rbp;
+ rip = GetRIP();
+ if(rip == SWITCH_MAGIC) {
+ outb(0x20, 0x20); // ACK Timer and return as child
+ return 0;
+ }
+
+ // Set EIP as parent
+ newThread->SavedState.RIP = rip;
+
+ // Lock list and add to active
+ Threads_AddActive(newThread);
+
+ return newThread->TID;
+}
+
+/**
+ * \fn int Proc_SpawnWorker()
+ * \brief Spawns a new worker thread
+ */
+int Proc_SpawnWorker()
+{
+ tThread *new, *cur;
+ Uint rip, rsp, rbp;
+
+ cur = Proc_GetCurThread();
+
+ // Create new thread
+ new = malloc( sizeof(tThread) );
+ if(!new) {
+ Warning("Proc_SpawnWorker - Out of heap space!\n");
+ return -1;
+ }
+ memcpy(new, &gThreadZero, sizeof(tThread));
+ // Set Thread ID
+ new->TID = giNextTID++;
+ // Create a new worker stack (in PID0's address space)
+ // The stack is relocated by this code
+ new->KernelStack = MM_NewWorkerStack();
+
+ // Get ESP and EBP based in the new stack
+ __asm__ __volatile__ ("mov %%rsp, %0": "=r"(rsp));
+ __asm__ __volatile__ ("mov %%rbp, %0": "=r"(rbp));
+ rsp = new->KernelStack - (cur->KernelStack - rsp);
+ rbp = new->KernelStack - (cur->KernelStack - rbp);
+
+ // Save core machine state
+ new->SavedState.RSP = rsp;
+ new->SavedState.RBP = rbp;
+ rip = GetRIP();
+ if(rip == SWITCH_MAGIC) {
+ outb(0x20, 0x20); // ACK Timer and return as child
+ return 0;
+ }
+
+ // Set EIP as parent
+ new->SavedState.RIP = rip;
+ // Mark as active
+ new->Status = THREAD_STAT_ACTIVE;
+ Threads_AddActive( new );
+
+ return new->TID;
+}
+
+/**
+ * \fn Uint Proc_MakeUserStack()
+ * \brief Creates a new user stack
+ */
+Uint Proc_MakeUserStack()
+{
+ int i;
+ Uint base = USER_STACK_TOP - USER_STACK_SZ;
+
+ // Check Prospective Space
+ for( i = USER_STACK_SZ >> 12; i--; )
+ if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
+ break;
+
+ if(i != -1) return 0;
+
+ // Allocate Stack - Allocate incrementally to clean up MM_Dump output
+ for( i = 0; i < USER_STACK_SZ/4069; i++ )
+ MM_Allocate( base + (i<<12) );
+
+ return base + USER_STACK_SZ;
+}
+
+
+/**
+ * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
+ * \brief Starts a user task
+ */
+void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
+{
+ Uint *stack = (void*)Proc_MakeUserStack();
+ int i;
+ Uint delta;
+ Uint16 ss, cs;
+
+ LOG("stack = 0x%x", stack);
+
+ // Copy Arguments
+ stack = (void*)( (Uint)stack - DataSize );
+ memcpy( stack, ArgV, DataSize );
+
+ // Adjust Arguments and environment
+ delta = (Uint)stack - (Uint)ArgV;
+ ArgV = (char**)stack;
+ for( i = 0; ArgV[i]; i++ ) ArgV[i] += delta;
+ i ++;
+ EnvP = &ArgV[i];
+ for( i = 0; EnvP[i]; i++ ) EnvP[i] += delta;
+
+ // User Mode Segments
+ ss = 0x23; cs = 0x1B;
+
+ // Arguments
+ *--stack = (Uint)EnvP;
+ *--stack = (Uint)ArgV;
+ *--stack = (Uint)ArgC;
+ while(*Bases)
+ *--stack = *Bases++;
+ *--stack = 0; // Return Address
+
+ Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
+}
+
+void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
+{
+ Uint *stack = (void*)Stack;
+ *--stack = SS; //Stack Segment
+ *--stack = Stack; //Stack Pointer
+ *--stack = Flags; //EFLAGS (Resvd (0x2) and IF (0x20))
+ *--stack = CS; //Code Segment
+ *--stack = IP; //EIP
+ //PUSHAD
+ *--stack = 0xAAAAAAAA; // eax
+ *--stack = 0xCCCCCCCC; // ecx
+ *--stack = 0xDDDDDDDD; // edx
+ *--stack = 0xBBBBBBBB; // ebx
+ *--stack = 0xD1D1D1D1; // edi
+ *--stack = 0x54545454; // rsp - NOT POPED
+ *--stack = 0x51515151; // esi
+ *--stack = 0xB4B4B4B4; // rbp
+ //Individual PUSHs
+ *--stack = SS; // ds
+
+ __asm__ __volatile__ (
+ "mov %%rax,%%rsp;\n\t" // Set stack pointer
+ "iret;\n\t" : : "a" (stack));
+ for(;;);
+}
+
+/**
+ * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
+ * \brief Demotes a process to a lower permission level
+ * \param Err Pointer to user's errno
+ * \param Dest New Permission Level
+ * \param Regs Pointer to user's register structure
+ */
+int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
+{
+ int cpl = Regs->cs & 3;
+ // Sanity Check
+ if(Dest > 3 || Dest < 0) {
+ *Err = -EINVAL;
+ return -1;
+ }
+
+ // Permission Check
+ if(cpl > Dest) {
+ *Err = -EACCES;
+ return -1;
+ }
+
+ // Change the Segment Registers
+ Regs->cs = (((Dest+1)<<4) | Dest) - 8;
+ Regs->ss = ((Dest+1)<<4) | Dest;
+ // Check if the GP Segs are GDT, then change them
+ if(!(Regs->ds & 4)) Regs->ds = ((Dest+1)<<4) | Dest;
+ if(!(Regs->es & 4)) Regs->es = ((Dest+1)<<4) | Dest;
+ if(!(Regs->fs & 4)) Regs->fs = ((Dest+1)<<4) | Dest;
+ if(!(Regs->gs & 4)) Regs->gs = ((Dest+1)<<4) | Dest;
+
+ return 0;
+}
+
+/**
+ * \brief Calls a signal handler in user mode
+ * \note Used for signals
+ */
+void Proc_CallFaultHandler(tThread *Thread)
+{
+ // Rewinds the stack and calls the user function
+ // Never returns
+ __asm__ __volatile__ ("mov %0, %%rbp;\n\tcall Proc_AlterUserReturnAddr" :: "r"(Thread->FaultHandler));
+ for(;;);
+}
+
+/**
+ * \fn void Proc_Scheduler(int CPU)
+ * \brief Swap current thread and clears dead threads
+ */
+void Proc_Scheduler(int CPU)
+{
+ Uint rsp, rbp, rip;
+ tThread *thread;
+
+ // If the spinlock is set, let it complete
+ if(IS_LOCKED(&glThreadListLock)) return;
+
+ // Clear Delete Queue
+ while(gDeleteThreads)
+ {
+ thread = gDeleteThreads->Next;
+ if(gDeleteThreads->IsLocked) { // Only free if structure is unused
+ gDeleteThreads->Status = THREAD_STAT_NULL;
+ free( gDeleteThreads );
+ }
+ gDeleteThreads = thread;
+ }
+
+ // Check if there is any tasks running
+ if(giNumActiveThreads == 0) {
+ Log("No Active threads, sleeping");
+ __asm__ __volatile__ ("hlt");
+ return;
+ }
+
+ // Get current thread
+ #if USE_MP
+ thread = gaCPUs[CPU].Current;
+ #else
+ thread = gCurrentThread;
+ #endif
+
+ // Reduce remaining quantum and continue timeslice if non-zero
+ if(thread->Remaining--) return;
+ // Reset quantum for next call
+ thread->Remaining = thread->Quantum;
+
+ // Get machine state
+ __asm__ __volatile__ ("mov %%rsp, %0":"=r"(rsp));
+ __asm__ __volatile__ ("mov %%rbp, %0":"=r"(rbp));
+ rip = GetRIP();
+ if(rip == SWITCH_MAGIC) return; // Check if a switch happened
+
+ // Save machine state
+ thread->SavedState.RSP = rsp;
+ thread->SavedState.RBP = rbp;
+ thread->SavedState.RIP = rip;
+
+ // Get next thread
+ thread = Threads_GetNextToRun(CPU);
+
+ // Error Check
+ if(thread == NULL) {
+ Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
+ return;
+ }
+
+ #if DEBUG_TRACE_SWITCH
+ Log("Switching to task %i, CR3 = 0x%x, RIP = %p",
+ thread->TID,
+ thread->MemState.CR3,
+ thread->SavedState.RIP
+ );
+ #endif
+
+ // Set current thread
+ #if USE_MP
+ gaCPUs[CPU].Current = thread;
+ #else
+ gCurrentThread = thread;
+ #endif
+
+ // Update Kernel Stack pointer
+ gTSSs[CPU].RSP0 = thread->KernelStack-4;
+
+ // Set address space
+ #if USE_PAE
+ # error "Todo: Implement PAE Address space switching"
+ #else
+ __asm__ __volatile__ ("mov %0, %%cr3"::"a"(thread->MemState.CR3));
+ #endif
+
+ #if 0
+ if(thread->SavedState.RSP > 0xC0000000
+ && thread->SavedState.RSP < thread->KernelStack-0x2000) {
+ Log_Warning("Proc", "Possible bad ESP %p (PID %i)", thread->SavedState.ESP);
+ }
+ #endif
+
+ // Switch threads
+ __asm__ __volatile__ (
+ "mov %1, %%rsp\n\t" // Restore RSP
+ "mov %2, %%rbp\n\t" // and RBP
+ "jmp *%3" : : // And return to where we saved state (Proc_Clone or Proc_Scheduler)
+ "a"(SWITCH_MAGIC), "b"(thread->SavedState.RSP),
+ "d"(thread->SavedState.RBP), "c"(thread->SavedState.RIP)
+ );
+ for(;;); // Shouldn't reach here
+}
+
+// === EXPORTS ===
+EXPORT(Proc_SpawnWorker);