2 * AcessOS Microkernel Version
16 #define DEBUG_TRACE_SWITCH 0
19 #define SWITCH_MAGIC 0xFF5317C8 // FF SWITCH - There is no code in this area
21 #define TIMER_BASE 1193182
22 #define TIMER_DIVISOR 11932 //~100Hz
29 Uint8 State; // 0: Unavaliable, 1: Idle, 2: Active
39 extern void APWait(void); // 16-bit AP pause code
40 extern void APStartup(void); // 16-bit AP startup code
41 extern Uint GetEIP(void); // start.asm
42 extern int GetCPUNum(void); // start.asm
43 extern Uint32 gaInitPageDir[1024]; // start.asm
44 extern char Kernel_Stack_Top[];
45 extern tShortSpinlock glThreadListLock;
48 extern tThread gThreadZero;
49 extern tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
50 extern void Isr8(void); // Double Fault
51 extern void Proc_ReturnToUser(tVAddr Handler, Uint Argument);
54 void ArchThreads_Init(void);
56 void MP_StartAP(int CPU);
57 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode);
59 void Proc_Start(void);
60 tThread *Proc_GetCurThread(void);
61 void Proc_ChangeStack(void);
62 int Proc_Clone(Uint *Err, Uint Flags);
63 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
64 void Proc_CallFaultHandler(tThread *Thread);
65 void Proc_Scheduler(int CPU);
68 // --- Multiprocessing ---
70 volatile int giNumInitingCPUs = 0;
71 tMPInfo *gMPFloatPtr = NULL;
72 volatile Uint32 giMP_TimerCount; // Start Count for Local APIC Timer
73 tAPIC *gpMP_LocalAPIC = NULL;
74 Uint8 gaAPIC_to_CPU[256] = {0};
75 tCPU gaCPUs[MAX_CPUS];
76 tTSS gaTSSs[MAX_CPUS]; // TSS Array
77 int giProc_BootProcessorID = 0;
79 tThread *gCurrentThread = NULL;
80 tThread *gpIdleThread = NULL;
83 Uint32 *gPML4s[4] = NULL;
85 tTSS *gTSSs = NULL; // Pointer to TSS array
87 // --- Error Recovery ---
88 char gaDoubleFaultStack[1024] __attribute__ ((section(".padata")));
89 tTSS gDoubleFault_TSS = {
90 .ESP0 = (Uint)&gaDoubleFaultStack[1024],
92 .CR3 = (Uint)gaInitPageDir - KERNEL_BASE,
94 .ESP = (Uint)&gaDoubleFaultStack[1024],
95 .CS = 0x08, .SS = 0x10,
96 .DS = 0x10, .ES = 0x10,
97 .FS = 0x10, .GS = 0x10,
102 * \fn void ArchThreads_Init(void)
103 * \brief Starts the process scheduler
105 void ArchThreads_Init(void)
112 // Mark BSP as active
115 // -- Initialise Multiprocessing
116 // Find MP Floating Table
117 // - EBDA/Last 1Kib (640KiB)
118 for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
119 if( *(Uint*)(pos) == MPPTR_IDENT ) {
120 Log("Possible %p", pos);
121 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
122 gMPFloatPtr = (void*)pos;
126 // - Last KiB (512KiB base mem)
128 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
129 if( *(Uint*)(pos) == MPPTR_IDENT ) {
130 Log("Possible %p", pos);
131 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
132 gMPFloatPtr = (void*)pos;
139 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
140 if( *(Uint*)(pos) == MPPTR_IDENT ) {
141 Log("Possible %p", pos);
142 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
143 gMPFloatPtr = (void*)pos;
149 // If the MP Table Exists, parse it
154 Log("gMPFloatPtr = %p", gMPFloatPtr);
155 Log("*gMPFloatPtr = {");
156 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
157 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
158 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
159 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
160 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
161 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
162 gMPFloatPtr->Features[0], gMPFloatPtr->Features[1],
163 gMPFloatPtr->Features[2], gMPFloatPtr->Features[3],
164 gMPFloatPtr->Features[4]
168 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
169 Log("mptable = %p", mptable);
171 Log("\t.Sig = 0x%08x", mptable->Sig);
172 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
173 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
174 Log("\t.Checksum = 0x%02x", mptable->Checksum);
175 Log("\t.OEMID = '%8c'", mptable->OemID);
176 Log("\t.ProductID = '%8c'", mptable->ProductID);
177 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
178 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
179 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
180 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
181 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
182 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
185 gpMP_LocalAPIC = (void*)MM_MapHWPages(mptable->LocalAPICMemMap, 1);
187 ents = mptable->Entries;
190 for( i = 0; i < mptable->EntryCount; i ++ )
197 Log("%i: Processor", i);
198 Log("\t.APICID = %i", ents->Proc.APICID);
199 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
200 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
201 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
202 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
205 if( !(ents->Proc.CPUFlags & 1) ) {
210 // Check if there is too many processors
211 if(giNumCPUs >= MAX_CPUS) {
212 giNumCPUs ++; // If `giNumCPUs` > MAX_CPUS later, it will be clipped
216 // Initialise CPU Info
217 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
218 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
219 gaCPUs[giNumCPUs].State = 0;
223 if( ents->Proc.CPUFlags & 2 ) {
224 giProc_BootProcessorID = giNumCPUs-1;
233 Log("\t.ID = %i", ents->Bus.ID);
234 Log("\t.TypeString = '%6C'", ents->Bus.TypeString);
238 Log("%i: I/O APIC", i);
239 Log("\t.ID = %i", ents->IOAPIC.ID);
240 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
241 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
242 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
244 case 3: // I/O Interrupt Assignment
246 Log("%i: I/O Interrupt Assignment", i);
247 Log("\t.IntType = %i", ents->IOInt.IntType);
248 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
249 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
250 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
251 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
252 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
254 case 4: // Local Interrupt Assignment
256 Log("%i: Local Interrupt Assignment", i);
257 Log("\t.IntType = %i", ents->LocalInt.IntType);
258 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
259 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
260 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
261 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
262 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
265 Log("%i: Unknown (%i)", i, ents->Type);
269 ents = (void*)( (Uint)ents + entSize );
272 if( giNumCPUs > MAX_CPUS ) {
273 Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
274 giNumCPUs = MAX_CPUS;
279 Log("No MP Table was found, assuming uniprocessor\n");
286 MM_FinishVirtualInit();
290 // Initialise Double Fault TSS
291 gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
292 gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
293 gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
295 // Set double fault IDT to use the new TSS
296 gIDT[8].OffsetLo = 0;
298 gIDT[8].Flags = 0x8500;
299 gIDT[8].OffsetHi = 0;
302 // Set timer frequency
303 outb(0x43, 0x34); // Set Channel 0, Low/High, Rate Generator
304 outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
305 outb(0x40, (TIMER_DIVISOR>>8)&0xFF); // High Byte
307 Log("Timer Frequency %i.%03i Hz",
308 TIMER_BASE/TIMER_DIVISOR,
309 ((Uint64)TIMER_BASE*1000/TIMER_DIVISOR)%1000
313 // Get the count setting for APIC timer
314 Log("Determining APIC Count");
315 __asm__ __volatile__ ("sti");
316 while( giMP_TimerCount == 0 ) __asm__ __volatile__ ("hlt");
317 __asm__ __volatile__ ("cli");
318 Log("APIC Count %i", giMP_TimerCount);
320 Uint64 freq = giMP_TimerCount;
321 freq /= TIMER_DIVISOR;
323 if( (freq /= 1000) < 2*1000)
324 Log("Bus Frequency %i KHz", freq);
325 else if( (freq /= 1000) < 2*1000)
326 Log("Bus Frequency %i MHz", freq);
327 else if( (freq /= 1000) < 2*1000)
328 Log("Bus Frequency %i GHz", freq);
330 Log("Bus Frequency %i THz", freq);
333 // Initialise Normal TSS(s)
334 for(pos=0;pos<giNumCPUs;pos++)
339 gTSSs[pos].SS0 = 0x10;
340 gTSSs[pos].ESP0 = 0; // Set properly by scheduler
341 gGDT[6+pos].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
342 gGDT[6+pos].BaseMid = ((Uint)(&gTSSs[pos]) >> 16) & 0xFFFF;
343 gGDT[6+pos].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
348 // Load the BSP's TSS
349 __asm__ __volatile__ ("ltr %%ax"::"a"(0x30));
350 // Set Current Thread and CPU Number in DR0 and DR1
351 __asm__ __volatile__ ("mov %0, %%db0"::"r"(&gThreadZero));
352 __asm__ __volatile__ ("mov %0, %%db1"::"r"(0));
355 gaCPUs[0].Current = &gThreadZero;
357 gCurrentThread = &gThreadZero;
359 gThreadZero.CurCPU = 0;
362 gThreadZero.MemState.PDP[0] = 0;
363 gThreadZero.MemState.PDP[1] = 0;
364 gThreadZero.MemState.PDP[2] = 0;
366 gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
369 // Create Per-Process Data Block
370 MM_Allocate(MM_PPD_CFG);
377 void MP_StartAP(int CPU)
379 Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
381 // Set location of AP startup code and mark for a warm restart
382 *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APWait - (KERNEL_BASE|0xFFFF0);
383 *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
384 outb(0x70, 0x0F); outb(0x71, 0x0A); // Set warm reset flag
385 MP_SendIPI(gaCPUs[CPU].APICID, 0, 5); // Init IPI
388 inb(0x80); inb(0x80); inb(0x80); inb(0x80);
390 // TODO: Use a better address, preferably registered with the MM
391 // - MM_AllocDMA mabye?
393 *(Uint8*)(KERNEL_BASE|0x11000) = 0xEA; // Far JMP
394 *(Uint16*)(KERNEL_BASE|0x11001) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0); // IP
395 *(Uint16*)(KERNEL_BASE|0x11003) = 0xFFFF; // CS
396 // Send a Startup-IPI to make the CPU execute at 0x11000 (which we
398 MP_SendIPI(gaCPUs[CPU].APICID, 0x11, 6); // StartupIPI
404 * \brief Send an Inter-Processor Interrupt
405 * \param APICID Processor's Local APIC ID
406 * \param Vector Argument of some kind
407 * \param DeliveryMode Type of signal?
409 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
414 val = (Uint)APICID << 24;
415 Log("*%p = 0x%08x", &gpMP_LocalAPIC->ICR[1], val);
416 gpMP_LocalAPIC->ICR[1].Val = val;
418 val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
419 Log("*%p = 0x%08x", &gpMP_LocalAPIC->ICR[0], val);
420 gpMP_LocalAPIC->ICR[0].Val = val;
425 * \fn void Proc_Start(void)
426 * \brief Start process scheduler
428 void Proc_Start(void)
436 for( i = 0; i < giNumCPUs; i ++ )
439 if(i) gaCPUs[i].Current = NULL;
442 if( (tid = Proc_Clone(0, 0)) == 0)
444 for(;;) HALT(); // Just yeilds
446 gaCPUs[i].IdleThread = Threads_GetThread(tid);
447 gaCPUs[i].IdleThread->ThreadName = "Idle Thread";
448 Threads_SetTickets( gaCPUs[i].IdleThread, 0 ); // Never called randomly
449 gaCPUs[i].IdleThread->Quantum = 1; // 1 slice quantum
453 if( i != giProc_BootProcessorID ) {
458 // BSP still should run the current task
459 gaCPUs[0].Current = &gThreadZero;
461 // Start interrupts and wait for APs to come up
462 Log("Waiting for APs to come up\n");
463 __asm__ __volatile__ ("sti");
464 while( giNumInitingCPUs ) __asm__ __volatile__ ("hlt");
467 if(Proc_Clone(0, 0) == 0)
469 gpIdleThread = Proc_GetCurThread();
470 gpIdleThread->ThreadName = "Idle Thread";
471 Threads_SetPriority( gpIdleThread, -1 ); // Never called randomly
472 gpIdleThread->Quantum = 1; // 1 slice quantum
473 for(;;) HALT(); // Just yeilds
477 gCurrentThread = &gThreadZero;
479 // Start Interrupts (and hence scheduler)
480 __asm__ __volatile__("sti");
482 MM_FinishVirtualInit();
486 * \fn tThread *Proc_GetCurThread(void)
487 * \brief Gets the current thread
489 tThread *Proc_GetCurThread(void)
492 return gaCPUs[ GetCPUNum() ].Current;
494 return gCurrentThread;
499 * \fn void Proc_ChangeStack(void)
500 * \brief Swaps the current stack for a new one (in the proper stack reigon)
502 void Proc_ChangeStack(void)
506 Uint curBase, newBase;
508 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
509 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
514 newBase = MM_NewKStack();
517 Panic("What the?? Unable to allocate space for initial kernel stack");
521 curBase = (Uint)&Kernel_Stack_Top;
523 LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
525 // Get ESP as a used size
527 LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
529 memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
530 // Get ESP as an offset in the new stack
533 ebp = newBase - (curBase - ebp);
535 // Repair EBPs & Stack Addresses
536 // Catches arguments also, but may trash stack-address-like values
537 for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
539 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
540 *(Uint*)tmpEbp += newBase - curBase;
543 Proc_GetCurThread()->KernelStack = newBase;
545 __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
546 __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
550 * \fn int Proc_Clone(Uint *Err, Uint Flags)
551 * \brief Clone the current process
553 int Proc_Clone(Uint *Err, Uint Flags)
556 tThread *cur = Proc_GetCurThread();
559 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
560 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
562 newThread = Threads_CloneTCB(Err, Flags);
563 if(!newThread) return -1;
565 // Initialise Memory Space (New Addr space or kernel stack)
566 if(Flags & CLONE_VM) {
567 newThread->MemState.CR3 = MM_Clone();
568 newThread->KernelStack = cur->KernelStack;
570 Uint tmpEbp, oldEsp = esp;
574 # warning "PAE Unimplemented"
576 newThread->MemState.CR3 = cur->MemState.CR3;
580 newThread->KernelStack = MM_NewKStack();
582 if(newThread->KernelStack == 0) {
587 // Get ESP as a used size
588 esp = cur->KernelStack - esp;
590 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
591 // Get ESP as an offset in the new stack
592 esp = newThread->KernelStack - esp;
594 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
596 // Repair EBPs & Stack Addresses
597 // Catches arguments also, but may trash stack-address-like values
598 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
600 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
601 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
605 // Save core machine state
606 newThread->SavedState.ESP = esp;
607 newThread->SavedState.EBP = ebp;
609 if(eip == SWITCH_MAGIC) {
610 __asm__ __volatile__ ("mov %0, %%db0" : : "r" (newThread) );
614 gpMP_LocalAPIC->EOI.Val = 0;
617 outb(0x20, 0x20); // ACK Timer and return as child
618 __asm__ __volatile__ ("sti"); // Restart interrupts
623 newThread->SavedState.EIP = eip;
625 // Lock list and add to active
626 Threads_AddActive(newThread);
628 return newThread->TID;
632 * \fn int Proc_SpawnWorker(void)
633 * \brief Spawns a new worker thread
635 int Proc_SpawnWorker(void)
640 cur = Proc_GetCurThread();
643 new = malloc( sizeof(tThread) );
645 Warning("Proc_SpawnWorker - Out of heap space!\n");
648 memcpy(new, &gThreadZero, sizeof(tThread));
650 new->TID = giNextTID++;
651 // Create a new worker stack (in PID0's address space)
652 // - The stack is relocated by this function
653 new->KernelStack = MM_NewWorkerStack();
655 // Get ESP and EBP based in the new stack
656 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
657 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
658 esp = new->KernelStack - (cur->KernelStack - esp);
659 ebp = new->KernelStack - (cur->KernelStack - ebp);
661 // Save core machine state
662 new->SavedState.ESP = esp;
663 new->SavedState.EBP = ebp;
665 if(eip == SWITCH_MAGIC) {
666 __asm__ __volatile__ ("mov %0, %%db0" : : "r"(new));
670 gpMP_LocalAPIC->EOI.Val = 0;
673 outb(0x20, 0x20); // ACK Timer and return as child
674 __asm__ __volatile__ ("sti"); // Restart interrupts
679 new->SavedState.EIP = eip;
681 Threads_AddActive( new );
687 * \fn Uint Proc_MakeUserStack(void)
688 * \brief Creates a new user stack
690 Uint Proc_MakeUserStack(void)
693 Uint base = USER_STACK_TOP - USER_STACK_SZ;
695 // Check Prospective Space
696 for( i = USER_STACK_SZ >> 12; i--; )
697 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
700 if(i != -1) return 0;
702 // Allocate Stack - Allocate incrementally to clean up MM_Dump output
703 for( i = 0; i < USER_STACK_SZ/0x1000; i++ )
704 MM_Allocate( base + (i<<12) );
706 return base + USER_STACK_SZ;
710 * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
711 * \brief Starts a user task
713 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
715 Uint *stack = (void*)Proc_MakeUserStack();
720 //Log("stack = %p", stack);
723 stack -= DataSize/sizeof(*stack);
724 memcpy( stack, ArgV, DataSize );
726 //Log("stack = %p", stack);
730 // Adjust Arguments and environment
731 delta = (Uint)stack - (Uint)ArgV;
732 ArgV = (char**)stack;
733 for( i = 0; ArgV[i]; i++ )
737 // Do we care about EnvP?
740 for( i = 0; EnvP[i]; i++ )
745 // User Mode Segments
746 ss = 0x23; cs = 0x1B;
749 *--stack = (Uint)EnvP;
750 *--stack = (Uint)ArgV;
751 *--stack = (Uint)ArgC;
754 *--stack = 0; // Return Address
756 Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
759 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
761 Uint *stack = (void*)Stack;
762 *--stack = SS; //Stack Segment
763 *--stack = Stack; //Stack Pointer
764 *--stack = Flags; //EFLAGS (Resvd (0x2) and IF (0x20))
765 *--stack = CS; //Code Segment
768 *--stack = 0xAAAAAAAA; // eax
769 *--stack = 0xCCCCCCCC; // ecx
770 *--stack = 0xDDDDDDDD; // edx
771 *--stack = 0xBBBBBBBB; // ebx
772 *--stack = 0xD1D1D1D1; // edi
773 *--stack = 0x54545454; // esp - NOT POPED
774 *--stack = 0x51515151; // esi
775 *--stack = 0xB4B4B4B4; // ebp
782 __asm__ __volatile__ (
783 "mov %%eax,%%esp;\n\t" // Set stack pointer
789 "iret;\n\t" : : "a" (stack));
794 * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
795 * \brief Demotes a process to a lower permission level
796 * \param Err Pointer to user's errno
797 * \param Dest New Permission Level
798 * \param Regs Pointer to user's register structure
800 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
802 int cpl = Regs->cs & 3;
804 if(Dest > 3 || Dest < 0) {
815 // Change the Segment Registers
816 Regs->cs = (((Dest+1)<<4) | Dest) - 8;
817 Regs->ss = ((Dest+1)<<4) | Dest;
818 // Check if the GP Segs are GDT, then change them
819 if(!(Regs->ds & 4)) Regs->ds = ((Dest+1)<<4) | Dest;
820 if(!(Regs->es & 4)) Regs->es = ((Dest+1)<<4) | Dest;
821 if(!(Regs->fs & 4)) Regs->fs = ((Dest+1)<<4) | Dest;
822 if(!(Regs->gs & 4)) Regs->gs = ((Dest+1)<<4) | Dest;
828 * \brief Calls a signal handler in user mode
829 * \note Used for signals
831 void Proc_CallFaultHandler(tThread *Thread)
833 // Rewinds the stack and calls the user function
835 Proc_ReturnToUser( Thread->FaultHandler, Thread->CurFaultNum );
840 * \fn void Proc_Scheduler(int CPU)
841 * \brief Swap current thread and clears dead threads
843 void Proc_Scheduler(int CPU)
848 // If the spinlock is set, let it complete
849 if(IS_LOCKED(&glThreadListLock)) return;
851 // Get current thread
853 thread = gaCPUs[CPU].Current;
855 thread = gCurrentThread;
860 // Reduce remaining quantum and continue timeslice if non-zero
861 if( thread->Remaining-- )
863 // Reset quantum for next call
864 thread->Remaining = thread->Quantum;
867 __asm__ __volatile__ ( "mov %%esp, %0" : "=r" (esp) );
868 __asm__ __volatile__ ( "mov %%ebp, %0" : "=r" (ebp) );
870 if(eip == SWITCH_MAGIC) return; // Check if a switch happened
872 // Save machine state
873 thread->SavedState.ESP = esp;
874 thread->SavedState.EBP = ebp;
875 thread->SavedState.EIP = eip;
878 // Get next thread to run
879 thread = Threads_GetNextToRun(CPU, thread);
881 // No avaliable tasks, just go into low power mode (idle thread)
884 thread = gaCPUs[CPU].IdleThread;
885 Log("CPU %i Running Idle Thread", CPU);
887 thread = gpIdleThread;
891 // Set current thread
893 gaCPUs[CPU].Current = thread;
895 gCurrentThread = thread;
898 #if DEBUG_TRACE_SWITCH
899 Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
901 thread->MemState.CR3,
902 thread->SavedState.EIP
906 #if USE_MP // MP Debug
907 Log("CPU = %i, Thread %p", CPU, thread);
910 // Update Kernel Stack pointer
911 gTSSs[CPU].ESP0 = thread->KernelStack-4;
915 # error "Todo: Implement PAE Address space switching"
917 __asm__ __volatile__ ("mov %0, %%cr3" : : "a" (thread->MemState.CR3));
921 if(thread->SavedState.ESP > 0xC0000000
922 && thread->SavedState.ESP < thread->KernelStack-0x2000) {
923 Log_Warning("Proc", "Possible bad ESP %p (PID %i)", thread->SavedState.ESP);
928 __asm__ __volatile__ (
929 "mov %1, %%esp\n\t" // Restore ESP
930 "mov %2, %%ebp\n\t" // and EBP
931 "jmp *%3" : : // And return to where we saved state (Proc_Clone or Proc_Scheduler)
932 "a"(SWITCH_MAGIC), "b"(thread->SavedState.ESP),
933 "d"(thread->SavedState.EBP), "c"(thread->SavedState.EIP)
935 for(;;); // Shouldn't reach here
939 EXPORT(Proc_SpawnWorker);