2 * AcessOS Microkernel Version
16 #define DEBUG_TRACE_SWITCH 0
17 #define DEBUG_DISABLE_DOUBLEFAULT 1
20 #define SWITCH_MAGIC 0xFF5317C8 // FF SWITCH - There is no code in this area
22 #define TIMER_BASE 1193182
23 #define TIMER_DIVISOR 11932 //~100Hz
30 Uint8 State; // 0: Unavaliable, 1: Idle, 2: Active
40 extern void APWait(void); // 16-bit AP pause code
41 extern void APStartup(void); // 16-bit AP startup code
42 extern Uint GetEIP(void); // start.asm
43 extern int GetCPUNum(void); // start.asm
44 extern Uint32 gaInitPageDir[1024]; // start.asm
45 extern char Kernel_Stack_Top[];
46 extern tShortSpinlock glThreadListLock;
49 extern tThread gThreadZero;
50 extern tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
51 extern void Isr8(void); // Double Fault
52 extern void Proc_ReturnToUser(tVAddr Handler, Uint Argument, tVAddr KernelStack);
55 void ArchThreads_Init(void);
57 void MP_StartAP(int CPU);
58 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode);
60 void Proc_Start(void);
61 tThread *Proc_GetCurThread(void);
62 void Proc_ChangeStack(void);
63 int Proc_Clone(Uint *Err, Uint Flags);
64 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
65 void Proc_CallFaultHandler(tThread *Thread);
66 void Proc_Scheduler(int CPU);
69 // --- Multiprocessing ---
71 volatile int giNumInitingCPUs = 0;
72 tMPInfo *gMPFloatPtr = NULL;
73 volatile Uint32 giMP_TimerCount; // Start Count for Local APIC Timer
74 tAPIC *gpMP_LocalAPIC = NULL;
75 Uint8 gaAPIC_to_CPU[256] = {0};
76 tCPU gaCPUs[MAX_CPUS];
77 tTSS gaTSSs[MAX_CPUS]; // TSS Array
78 int giProc_BootProcessorID = 0;
80 tThread *gCurrentThread = NULL;
81 tThread *gpIdleThread = NULL;
84 Uint32 *gPML4s[4] = NULL;
86 tTSS *gTSSs = NULL; // Pointer to TSS array
88 // --- Error Recovery ---
89 char gaDoubleFaultStack[1024] __attribute__ ((section(".padata")));
90 tTSS gDoubleFault_TSS = {
91 .ESP0 = (Uint)&gaDoubleFaultStack[1024],
93 .CR3 = (Uint)gaInitPageDir - KERNEL_BASE,
95 .ESP = (Uint)&gaDoubleFaultStack[1024],
96 .CS = 0x08, .SS = 0x10,
97 .DS = 0x10, .ES = 0x10,
98 .FS = 0x10, .GS = 0x10,
103 * \fn void ArchThreads_Init(void)
104 * \brief Starts the process scheduler
106 void ArchThreads_Init(void)
113 // Mark BSP as active
116 // -- Initialise Multiprocessing
117 // Find MP Floating Table
118 // - EBDA/Last 1Kib (640KiB)
119 for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
120 if( *(Uint*)(pos) == MPPTR_IDENT ) {
121 Log("Possible %p", pos);
122 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
123 gMPFloatPtr = (void*)pos;
127 // - Last KiB (512KiB base mem)
129 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
130 if( *(Uint*)(pos) == MPPTR_IDENT ) {
131 Log("Possible %p", pos);
132 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
133 gMPFloatPtr = (void*)pos;
140 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
141 if( *(Uint*)(pos) == MPPTR_IDENT ) {
142 Log("Possible %p", pos);
143 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
144 gMPFloatPtr = (void*)pos;
150 // If the MP Table Exists, parse it
155 Log("gMPFloatPtr = %p", gMPFloatPtr);
156 Log("*gMPFloatPtr = {");
157 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
158 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
159 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
160 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
161 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
162 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
163 gMPFloatPtr->Features[0], gMPFloatPtr->Features[1],
164 gMPFloatPtr->Features[2], gMPFloatPtr->Features[3],
165 gMPFloatPtr->Features[4]
169 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
170 Log("mptable = %p", mptable);
172 Log("\t.Sig = 0x%08x", mptable->Sig);
173 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
174 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
175 Log("\t.Checksum = 0x%02x", mptable->Checksum);
176 Log("\t.OEMID = '%8c'", mptable->OemID);
177 Log("\t.ProductID = '%8c'", mptable->ProductID);
178 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
179 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
180 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
181 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
182 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
183 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
186 gpMP_LocalAPIC = (void*)MM_MapHWPages(mptable->LocalAPICMemMap, 1);
188 ents = mptable->Entries;
191 for( i = 0; i < mptable->EntryCount; i ++ )
198 Log("%i: Processor", i);
199 Log("\t.APICID = %i", ents->Proc.APICID);
200 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
201 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
202 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
203 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
206 if( !(ents->Proc.CPUFlags & 1) ) {
211 // Check if there is too many processors
212 if(giNumCPUs >= MAX_CPUS) {
213 giNumCPUs ++; // If `giNumCPUs` > MAX_CPUS later, it will be clipped
217 // Initialise CPU Info
218 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
219 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
220 gaCPUs[giNumCPUs].State = 0;
224 if( ents->Proc.CPUFlags & 2 ) {
225 giProc_BootProcessorID = giNumCPUs-1;
234 Log("\t.ID = %i", ents->Bus.ID);
235 Log("\t.TypeString = '%6C'", ents->Bus.TypeString);
239 Log("%i: I/O APIC", i);
240 Log("\t.ID = %i", ents->IOAPIC.ID);
241 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
242 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
243 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
245 case 3: // I/O Interrupt Assignment
247 Log("%i: I/O Interrupt Assignment", i);
248 Log("\t.IntType = %i", ents->IOInt.IntType);
249 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
250 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
251 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
252 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
253 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
255 case 4: // Local Interrupt Assignment
257 Log("%i: Local Interrupt Assignment", i);
258 Log("\t.IntType = %i", ents->LocalInt.IntType);
259 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
260 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
261 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
262 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
263 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
266 Log("%i: Unknown (%i)", i, ents->Type);
270 ents = (void*)( (Uint)ents + entSize );
273 if( giNumCPUs > MAX_CPUS ) {
274 Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
275 giNumCPUs = MAX_CPUS;
280 Log("No MP Table was found, assuming uniprocessor\n");
287 MM_FinishVirtualInit();
290 #if !DEBUG_DISABLE_DOUBLEFAULT
291 // Initialise Double Fault TSS
292 gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
293 gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
294 gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
296 // Set double fault IDT to use the new TSS
297 gIDT[8].OffsetLo = 0;
299 gIDT[8].Flags = 0x8500;
300 gIDT[8].OffsetHi = 0;
303 // Set timer frequency
304 outb(0x43, 0x34); // Set Channel 0, Low/High, Rate Generator
305 outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
306 outb(0x40, (TIMER_DIVISOR>>8)&0xFF); // High Byte
308 Log("Timer Frequency %i.%03i Hz",
309 TIMER_BASE/TIMER_DIVISOR,
310 ((Uint64)TIMER_BASE*1000/TIMER_DIVISOR)%1000
314 // Get the count setting for APIC timer
315 Log("Determining APIC Count");
316 __asm__ __volatile__ ("sti");
317 while( giMP_TimerCount == 0 ) __asm__ __volatile__ ("hlt");
318 __asm__ __volatile__ ("cli");
319 Log("APIC Count %i", giMP_TimerCount);
321 Uint64 freq = giMP_TimerCount;
322 freq /= TIMER_DIVISOR;
324 if( (freq /= 1000) < 2*1000)
325 Log("Bus Frequency %i KHz", freq);
326 else if( (freq /= 1000) < 2*1000)
327 Log("Bus Frequency %i MHz", freq);
328 else if( (freq /= 1000) < 2*1000)
329 Log("Bus Frequency %i GHz", freq);
331 Log("Bus Frequency %i THz", freq);
334 // Initialise Normal TSS(s)
335 for(pos=0;pos<giNumCPUs;pos++)
340 gTSSs[pos].SS0 = 0x10;
341 gTSSs[pos].ESP0 = 0; // Set properly by scheduler
342 gGDT[6+pos].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
343 gGDT[6+pos].BaseMid = ((Uint)(&gTSSs[pos]) >> 16) & 0xFFFF;
344 gGDT[6+pos].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
349 // Load the BSP's TSS
350 __asm__ __volatile__ ("ltr %%ax"::"a"(0x30));
351 // Set Current Thread and CPU Number in DR0 and DR1
352 __asm__ __volatile__ ("mov %0, %%db0"::"r"(&gThreadZero));
353 __asm__ __volatile__ ("mov %0, %%db1"::"r"(0));
356 gaCPUs[0].Current = &gThreadZero;
358 gCurrentThread = &gThreadZero;
360 gThreadZero.CurCPU = 0;
363 gThreadZero.MemState.PDP[0] = 0;
364 gThreadZero.MemState.PDP[1] = 0;
365 gThreadZero.MemState.PDP[2] = 0;
367 gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
370 // Create Per-Process Data Block
371 if( !MM_Allocate(MM_PPD_CFG) )
373 Panic("OOM - No space for initiali Per-Process Config");
381 void MP_StartAP(int CPU)
383 Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
385 // Set location of AP startup code and mark for a warm restart
386 *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APWait - (KERNEL_BASE|0xFFFF0);
387 *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
388 outb(0x70, 0x0F); outb(0x71, 0x0A); // Set warm reset flag
389 MP_SendIPI(gaCPUs[CPU].APICID, 0, 5); // Init IPI
392 inb(0x80); inb(0x80); inb(0x80); inb(0x80);
394 // TODO: Use a better address, preferably registered with the MM
395 // - MM_AllocDMA mabye?
397 *(Uint8*)(KERNEL_BASE|0x11000) = 0xEA; // Far JMP
398 *(Uint16*)(KERNEL_BASE|0x11001) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0); // IP
399 *(Uint16*)(KERNEL_BASE|0x11003) = 0xFFFF; // CS
400 // Send a Startup-IPI to make the CPU execute at 0x11000 (which we
402 MP_SendIPI(gaCPUs[CPU].APICID, 0x11, 6); // StartupIPI
408 * \brief Send an Inter-Processor Interrupt
409 * \param APICID Processor's Local APIC ID
410 * \param Vector Argument of some kind
411 * \param DeliveryMode Type of signal?
413 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
418 val = (Uint)APICID << 24;
419 Log("*%p = 0x%08x", &gpMP_LocalAPIC->ICR[1], val);
420 gpMP_LocalAPIC->ICR[1].Val = val;
422 val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
423 Log("*%p = 0x%08x", &gpMP_LocalAPIC->ICR[0], val);
424 gpMP_LocalAPIC->ICR[0].Val = val;
429 * \fn void Proc_Start(void)
430 * \brief Start process scheduler
432 void Proc_Start(void)
440 for( i = 0; i < giNumCPUs; i ++ )
443 if(i) gaCPUs[i].Current = NULL;
446 if( (tid = Proc_Clone(0, 0)) == 0)
448 for(;;) HALT(); // Just yeilds
450 gaCPUs[i].IdleThread = Threads_GetThread(tid);
451 gaCPUs[i].IdleThread->ThreadName = "Idle Thread";
452 Threads_SetPriority( gaCPUs[i].IdleThread, -1 ); // Never called randomly
453 gaCPUs[i].IdleThread->Quantum = 1; // 1 slice quantum
457 if( i != giProc_BootProcessorID ) {
462 // BSP still should run the current task
463 gaCPUs[0].Current = &gThreadZero;
465 // Start interrupts and wait for APs to come up
466 Log("Waiting for APs to come up\n");
467 __asm__ __volatile__ ("sti");
468 while( giNumInitingCPUs ) __asm__ __volatile__ ("hlt");
471 if(Proc_Clone(0, 0) == 0)
473 gpIdleThread = Proc_GetCurThread();
474 gpIdleThread->ThreadName = "Idle Thread";
475 Threads_SetPriority( gpIdleThread, -1 ); // Never called randomly
476 gpIdleThread->Quantum = 1; // 1 slice quantum
477 for(;;) HALT(); // Just yeilds
481 gCurrentThread = &gThreadZero;
483 // Start Interrupts (and hence scheduler)
484 __asm__ __volatile__("sti");
486 MM_FinishVirtualInit();
490 * \fn tThread *Proc_GetCurThread(void)
491 * \brief Gets the current thread
493 tThread *Proc_GetCurThread(void)
496 return gaCPUs[ GetCPUNum() ].Current;
498 return gCurrentThread;
503 * \fn void Proc_ChangeStack(void)
504 * \brief Swaps the current stack for a new one (in the proper stack reigon)
506 void Proc_ChangeStack(void)
510 Uint curBase, newBase;
512 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
513 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
518 newBase = MM_NewKStack();
521 Panic("What the?? Unable to allocate space for initial kernel stack");
525 curBase = (Uint)&Kernel_Stack_Top;
527 LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
529 // Get ESP as a used size
531 LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
533 memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
534 // Get ESP as an offset in the new stack
537 ebp = newBase - (curBase - ebp);
539 // Repair EBPs & Stack Addresses
540 // Catches arguments also, but may trash stack-address-like values
541 for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
543 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
544 *(Uint*)tmpEbp += newBase - curBase;
547 Proc_GetCurThread()->KernelStack = newBase;
549 __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
550 __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
554 * \fn int Proc_Clone(Uint *Err, Uint Flags)
555 * \brief Clone the current process
557 int Proc_Clone(Uint *Err, Uint Flags)
560 tThread *cur = Proc_GetCurThread();
563 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
564 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
566 newThread = Threads_CloneTCB(Err, Flags);
567 if(!newThread) return -1;
569 // Initialise Memory Space (New Addr space or kernel stack)
570 if(Flags & CLONE_VM) {
571 newThread->MemState.CR3 = MM_Clone();
573 if(newThread->MemState.CR3 == 0) {
574 Threads_Kill(newThread, -2);
577 newThread->KernelStack = cur->KernelStack;
579 Uint tmpEbp, oldEsp = esp;
583 # warning "PAE Unimplemented"
585 newThread->MemState.CR3 = cur->MemState.CR3;
589 newThread->KernelStack = MM_NewKStack();
591 if(newThread->KernelStack == 0) {
592 Threads_Kill(newThread, -2);
596 // Get ESP as a used size
597 esp = cur->KernelStack - esp;
599 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
600 // Get ESP as an offset in the new stack
601 esp = newThread->KernelStack - esp;
603 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
605 // Repair EBPs & Stack Addresses
606 // Catches arguments also, but may trash stack-address-like values
607 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
609 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
610 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
614 // Save core machine state
615 newThread->SavedState.ESP = esp;
616 newThread->SavedState.EBP = ebp;
618 if(eip == SWITCH_MAGIC) {
619 __asm__ __volatile__ ("mov %0, %%db0" : : "r" (newThread) );
623 gpMP_LocalAPIC->EOI.Val = 0;
626 outb(0x20, 0x20); // ACK Timer and return as child
627 __asm__ __volatile__ ("sti"); // Restart interrupts
632 newThread->SavedState.EIP = eip;
634 // Lock list and add to active
635 Threads_AddActive(newThread);
637 return newThread->TID;
641 * \fn int Proc_SpawnWorker(void)
642 * \brief Spawns a new worker thread
644 int Proc_SpawnWorker(void)
649 cur = Proc_GetCurThread();
652 new = malloc( sizeof(tThread) );
654 Warning("Proc_SpawnWorker - Out of heap space!\n");
657 memcpy(new, &gThreadZero, sizeof(tThread));
659 new->TID = giNextTID++;
660 // Create a new worker stack (in PID0's address space)
661 // - The stack is relocated by this function
662 new->KernelStack = MM_NewWorkerStack();
664 // Get ESP and EBP based in the new stack
665 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
666 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
667 esp = new->KernelStack - (cur->KernelStack - esp);
668 ebp = new->KernelStack - (cur->KernelStack - ebp);
670 // Save core machine state
671 new->SavedState.ESP = esp;
672 new->SavedState.EBP = ebp;
674 if(eip == SWITCH_MAGIC) {
675 __asm__ __volatile__ ("mov %0, %%db0" : : "r"(new));
679 gpMP_LocalAPIC->EOI.Val = 0;
682 outb(0x20, 0x20); // ACK Timer and return as child
683 __asm__ __volatile__ ("sti"); // Restart interrupts
688 new->SavedState.EIP = eip;
690 Threads_AddActive( new );
696 * \fn Uint Proc_MakeUserStack(void)
697 * \brief Creates a new user stack
699 Uint Proc_MakeUserStack(void)
702 Uint base = USER_STACK_TOP - USER_STACK_SZ;
704 // Check Prospective Space
705 for( i = USER_STACK_SZ >> 12; i--; )
706 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
709 if(i != -1) return 0;
711 // Allocate Stack - Allocate incrementally to clean up MM_Dump output
712 for( i = 0; i < USER_STACK_SZ/0x1000; i++ )
714 if( !MM_Allocate( base + (i<<12) ) )
716 Warning("OOM: Proc_MakeUserStack");
721 return base + USER_STACK_SZ;
725 * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
726 * \brief Starts a user task
728 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
730 Uint *stack = (void*)Proc_MakeUserStack();
735 //Log("stack = %p", stack);
738 stack -= DataSize/sizeof(*stack);
739 memcpy( stack, ArgV, DataSize );
741 //Log("stack = %p", stack);
745 // Adjust Arguments and environment
746 delta = (Uint)stack - (Uint)ArgV;
747 ArgV = (char**)stack;
748 for( i = 0; ArgV[i]; i++ )
752 // Do we care about EnvP?
755 for( i = 0; EnvP[i]; i++ )
760 // User Mode Segments
761 ss = 0x23; cs = 0x1B;
764 *--stack = (Uint)EnvP;
765 *--stack = (Uint)ArgV;
766 *--stack = (Uint)ArgC;
769 *--stack = 0; // Return Address
771 Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
774 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
776 Uint *stack = (void*)Stack;
777 *--stack = SS; //Stack Segment
778 *--stack = Stack; //Stack Pointer
779 *--stack = Flags; //EFLAGS (Resvd (0x2) and IF (0x20))
780 *--stack = CS; //Code Segment
783 *--stack = 0xAAAAAAAA; // eax
784 *--stack = 0xCCCCCCCC; // ecx
785 *--stack = 0xDDDDDDDD; // edx
786 *--stack = 0xBBBBBBBB; // ebx
787 *--stack = 0xD1D1D1D1; // edi
788 *--stack = 0x54545454; // esp - NOT POPED
789 *--stack = 0x51515151; // esi
790 *--stack = 0xB4B4B4B4; // ebp
797 __asm__ __volatile__ (
798 "mov %%eax,%%esp;\n\t" // Set stack pointer
804 "iret;\n\t" : : "a" (stack));
809 * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
810 * \brief Demotes a process to a lower permission level
811 * \param Err Pointer to user's errno
812 * \param Dest New Permission Level
813 * \param Regs Pointer to user's register structure
815 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
817 int cpl = Regs->cs & 3;
819 if(Dest > 3 || Dest < 0) {
830 // Change the Segment Registers
831 Regs->cs = (((Dest+1)<<4) | Dest) - 8;
832 Regs->ss = ((Dest+1)<<4) | Dest;
833 // Check if the GP Segs are GDT, then change them
834 if(!(Regs->ds & 4)) Regs->ds = ((Dest+1)<<4) | Dest;
835 if(!(Regs->es & 4)) Regs->es = ((Dest+1)<<4) | Dest;
836 if(!(Regs->fs & 4)) Regs->fs = ((Dest+1)<<4) | Dest;
837 if(!(Regs->gs & 4)) Regs->gs = ((Dest+1)<<4) | Dest;
843 * \brief Calls a signal handler in user mode
844 * \note Used for signals
846 void Proc_CallFaultHandler(tThread *Thread)
848 // Rewinds the stack and calls the user function
850 Proc_ReturnToUser( Thread->FaultHandler, Thread->CurFaultNum, Thread->KernelStack );
855 * \fn void Proc_Scheduler(int CPU)
856 * \brief Swap current thread and clears dead threads
858 void Proc_Scheduler(int CPU)
863 // If the spinlock is set, let it complete
864 if(IS_LOCKED(&glThreadListLock)) return;
866 // Get current thread
868 thread = gaCPUs[CPU].Current;
870 thread = gCurrentThread;
875 // Reduce remaining quantum and continue timeslice if non-zero
876 if( thread->Remaining-- )
878 // Reset quantum for next call
879 thread->Remaining = thread->Quantum;
882 __asm__ __volatile__ ( "mov %%esp, %0" : "=r" (esp) );
883 __asm__ __volatile__ ( "mov %%ebp, %0" : "=r" (ebp) );
885 if(eip == SWITCH_MAGIC) return; // Check if a switch happened
887 // Save machine state
888 thread->SavedState.ESP = esp;
889 thread->SavedState.EBP = ebp;
890 thread->SavedState.EIP = eip;
893 // Get next thread to run
894 thread = Threads_GetNextToRun(CPU, thread);
896 // No avaliable tasks, just go into low power mode (idle thread)
899 thread = gaCPUs[CPU].IdleThread;
900 Log("CPU %i Running Idle Thread", CPU);
902 thread = gpIdleThread;
906 // Set current thread
908 gaCPUs[CPU].Current = thread;
910 gCurrentThread = thread;
913 #if DEBUG_TRACE_SWITCH
914 Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
916 thread->MemState.CR3,
917 thread->SavedState.EIP
921 #if USE_MP // MP Debug
922 Log("CPU = %i, Thread %p", CPU, thread);
925 // Update Kernel Stack pointer
926 gTSSs[CPU].ESP0 = thread->KernelStack-4;
930 # error "Todo: Implement PAE Address space switching"
932 __asm__ __volatile__ ("mov %0, %%cr3" : : "a" (thread->MemState.CR3));
936 if(thread->SavedState.ESP > 0xC0000000
937 && thread->SavedState.ESP < thread->KernelStack-0x2000) {
938 Log_Warning("Proc", "Possible bad ESP %p (PID %i)", thread->SavedState.ESP);
943 __asm__ __volatile__ (
944 "mov %1, %%esp\n\t" // Restore ESP
945 "mov %2, %%ebp\n\t" // and EBP
946 "jmp *%3" : : // And return to where we saved state (Proc_Clone or Proc_Scheduler)
947 "a"(SWITCH_MAGIC), "b"(thread->SavedState.ESP),
948 "d"(thread->SavedState.EBP), "c"(thread->SavedState.EIP)
950 for(;;); // Shouldn't reach here
954 EXPORT(Proc_SpawnWorker);