2 * AcessOS Microkernel Version
14 #define DEBUG_TRACE_SWITCH 0
17 #define SWITCH_MAGIC 0xFFFACE55 // There is no code in this area
18 #define TIMER_DIVISOR 11931 //~100Hz
22 extern void APStartup(); // 16-bit AP startup code
23 extern Uint GetEIP(); // start.asm
24 extern Uint32 gaInitPageDir[1024]; // start.asm
25 extern void Kernel_Stack_Top;
26 extern volatile int giThreadListLock;
29 extern int giTotalTickets;
30 extern int giNumActiveThreads;
31 extern tThread gThreadZero;
32 extern tThread *gActiveThreads;
33 extern tThread *gSleepingThreads;
34 extern tThread *gDeleteThreads;
35 extern tThread *Threads_GetNextToRun(int CPU);
36 extern void Threads_Dump();
37 extern tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
41 void ArchThreads_Init();
43 void MP_StartAP(int CPU);
44 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode);
47 tThread *Proc_GetCurThread();
48 void Proc_ChangeStack();
49 int Proc_Clone(Uint *Err, Uint Flags);
50 void Proc_Scheduler();
53 // --- Multiprocessing ---
55 tMPInfo *gMPFloatPtr = NULL;
56 tIOAPIC *gpMP_LocalAPIC = NULL;
57 Uint8 gaAPIC_to_CPU[256] = {0};
58 tCPU gaCPUs[MAX_CPUS];
60 tThread *gCurrentThread = NULL;
63 Uint32 *gPML4s[4] = NULL;
67 // --- Error Recovery ---
68 char gaDoubleFaultStack[1024];
69 tTSS gDoubleFault_TSS = {
70 .ESP0 = (Uint)&gaDoubleFaultStack[1023],
77 * \fn void ArchThreads_Init()
78 * \brief Starts the process scheduler
80 void ArchThreads_Init()
90 // -- Initialise Multiprocessing
91 // Find MP Floating Table
92 // - EBDA/Last 1Kib (640KiB)
93 for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
94 if( *(Uint*)(pos) == MPPTR_IDENT ) {
95 Log("Possible %p", pos);
96 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
97 gMPFloatPtr = (void*)pos;
101 // - Last KiB (512KiB base mem)
103 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
104 if( *(Uint*)(pos) == MPPTR_IDENT ) {
105 Log("Possible %p", pos);
106 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
107 gMPFloatPtr = (void*)pos;
114 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
115 if( *(Uint*)(pos) == MPPTR_IDENT ) {
116 Log("Possible %p", pos);
117 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
118 gMPFloatPtr = (void*)pos;
124 // If the MP Table Exists, parse it
129 Log("gMPFloatPtr = %p", gMPFloatPtr);
130 Log("*gMPFloatPtr = {");
131 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
132 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
133 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
134 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
135 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
136 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
137 gMPFloatPtr->Features[0], gMPFloatPtr->Features[1],
138 gMPFloatPtr->Features[2], gMPFloatPtr->Features[3],
139 gMPFloatPtr->Features[4]
143 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
144 Log("mptable = %p", mptable);
146 Log("\t.Sig = 0x%08x", mptable->Sig);
147 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
148 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
149 Log("\t.Checksum = 0x%02x", mptable->Checksum);
150 Log("\t.OEMID = '%8c'", mptable->OemID);
151 Log("\t.ProductID = '%8c'", mptable->ProductID);
152 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
153 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
154 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
155 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
156 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
157 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
160 gpMP_LocalAPIC = (void*)MM_MapHWPage(mptable->LocalAPICMemMap, 1);
162 ents = mptable->Entries;
165 for( i = 0; i < mptable->EntryCount; i ++ )
172 Log("%i: Processor", i);
173 Log("\t.APICID = %i", ents->Proc.APICID);
174 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
175 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
176 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
177 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
179 // Check if there is too many processors
180 if(giNumCPUs >= MAX_CPUS) {
181 giNumCPUs ++; // If `giNumCPUs` > MAX_CPUS later, it will be clipped
185 // Initialise CPU Info
186 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
187 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
188 gaCPUs[giNumCPUs].State = 0;
192 MP_StartAP( giNumCPUs-1 );
198 Log("\t.ID = %i", ents->Bus.ID);
199 Log("\t.TypeString = '%6c'", ents->Bus.TypeString);
203 Log("%i: I/O APIC", i);
204 Log("\t.ID = %i", ents->IOAPIC.ID);
205 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
206 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
207 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
209 case 3: // I/O Interrupt Assignment
211 Log("%i: I/O Interrupt Assignment", i);
212 Log("\t.IntType = %i", ents->IOInt.IntType);
213 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
214 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
215 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
216 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
217 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
219 case 4: // Local Interrupt Assignment
221 Log("%i: Local Interrupt Assignment", i);
222 Log("\t.IntType = %i", ents->LocalInt.IntType);
223 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
224 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
225 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
226 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
227 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
230 Log("%i: Unknown (%i)", i, ents->Type);
233 ents = (void*)( (Uint)ents + entSize );
236 if( giNumCPUs > MAX_CPUS ) {
237 Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
240 Panic("Uh oh... MP Table Parsing is unimplemented\n");
243 Log("No MP Table was found, assuming uniprocessor\n");
252 // Initialise Double Fault TSS
254 gGDT[5].LimitLow = sizeof(tTSS);
256 gGDT[5].Access = 0x89; // Type
259 gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
260 gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
261 gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
264 // Initialise Normal TSS(s)
265 for(pos=0;pos<giNumCPUs;pos++)
270 gTSSs[pos].SS0 = 0x10;
271 gTSSs[pos].ESP0 = 0; // Set properly by scheduler
272 gGDT[6+pos].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
273 gGDT[6+pos].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
274 gGDT[6+pos].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
277 for(pos=0;pos<giNumCPUs;pos++) {
279 __asm__ __volatile__ ("ltr %%ax"::"a"(0x30+pos*8));
285 gaCPUs[0].Current = &gThreadZero;
287 gCurrentThread = &gThreadZero;
291 gThreadZero.MemState.PDP[0] = 0;
292 gThreadZero.MemState.PDP[1] = 0;
293 gThreadZero.MemState.PDP[2] = 0;
295 gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
298 // Set timer frequency
299 outb(0x43, 0x34); // Set Channel 0, Low/High, Rate Generator
300 outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
301 outb(0x40, (TIMER_DIVISOR>>8)&0xFF); // High Byte
303 // Create Per-Process Data Block
304 MM_Allocate(MM_PPD_CFG);
311 void MP_StartAP(int CPU)
313 Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
314 // Set location of AP startup code and mark for a warm restart
315 *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);
316 *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
317 outb(0x70, 0x0F); outb(0x71, 0x0A); // Warm Reset
318 MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);
321 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
323 Uint32 addr = (Uint)gpMP_LocalAPIC + 0x20 + (APICID<<3);
325 *(Uint32*)addr = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
330 * \fn void Proc_Start()
331 * \brief Start process scheduler
335 // Start Interrupts (and hence scheduler)
336 __asm__ __volatile__("sti");
340 * \fn tThread *Proc_GetCurThread()
341 * \brief Gets the current thread
343 tThread *Proc_GetCurThread()
346 gpMP_LocalAPIC->Addr = 0;
347 return gaCPUs[ gaAPIC_to_CPU[gpMP_LocalAPIC->Value.Byte] ].Current;
349 return gCurrentThread;
354 * \fn void Proc_ChangeStack()
355 * \brief Swaps the current stack for a new one (in the proper stack reigon)
357 void Proc_ChangeStack()
361 Uint curBase, newBase;
363 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
364 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
369 newBase = MM_NewKStack();
372 Panic("What the?? Unable to allocate space for initial kernel stack");
376 curBase = (Uint)&Kernel_Stack_Top;
378 LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
380 // Get ESP as a used size
382 LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
384 memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
385 // Get ESP as an offset in the new stack
388 ebp = newBase - (curBase - ebp);
390 // Repair EBPs & Stack Addresses
391 // Catches arguments also, but may trash stack-address-like values
392 for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
394 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
395 *(Uint*)tmpEbp += newBase - curBase;
398 Proc_GetCurThread()->KernelStack = newBase;
400 __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
401 __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
405 * \fn int Proc_Clone(Uint *Err, Uint Flags)
406 * \brief Clone the current process
408 int Proc_Clone(Uint *Err, Uint Flags)
411 tThread *cur = Proc_GetCurThread();
414 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
415 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
417 newThread = Threads_CloneTCB(Err, Flags);
418 if(!newThread) return -1;
420 // Initialise Memory Space (New Addr space or kernel stack)
421 if(Flags & CLONE_VM) {
422 newThread->MemState.CR3 = MM_Clone();
423 newThread->KernelStack = cur->KernelStack;
425 Uint tmpEbp, oldEsp = esp;
428 newThread->MemState.CR3 = cur->MemState.CR3;
431 newThread->KernelStack = MM_NewKStack();
433 if(newThread->KernelStack == 0) {
438 // Get ESP as a used size
439 esp = cur->KernelStack - esp;
441 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
442 // Get ESP as an offset in the new stack
443 esp = newThread->KernelStack - esp;
445 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
447 // Repair EBPs & Stack Addresses
448 // Catches arguments also, but may trash stack-address-like values
449 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
451 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
452 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
456 // Save core machine state
457 newThread->SavedState.ESP = esp;
458 newThread->SavedState.EBP = ebp;
460 if(eip == SWITCH_MAGIC) {
461 outb(0x20, 0x20); // ACK Timer and return as child
466 newThread->SavedState.EIP = eip;
468 // Lock list and add to active
469 Threads_AddActive(newThread);
471 return newThread->TID;
475 * \fn int Proc_SpawnWorker()
476 * \brief Spawns a new worker thread
478 int Proc_SpawnWorker()
483 cur = Proc_GetCurThread();
486 new = malloc( sizeof(tThread) );
488 Warning("Proc_SpawnWorker - Out of heap space!\n");
491 memcpy(new, &gThreadZero, sizeof(tThread));
493 new->TID = giNextTID++;
494 // Create a new worker stack (in PID0's address space)
495 // The stack is relocated by this code
496 new->KernelStack = MM_NewWorkerStack();
498 // Get ESP and EBP based in the new stack
499 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
500 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
501 esp = new->KernelStack - (cur->KernelStack - esp);
502 ebp = new->KernelStack - (cur->KernelStack - ebp);
504 // Save core machine state
505 new->SavedState.ESP = esp;
506 new->SavedState.EBP = ebp;
508 if(eip == SWITCH_MAGIC) {
509 outb(0x20, 0x20); // ACK Timer and return as child
514 new->SavedState.EIP = eip;
516 new->Status = THREAD_STAT_ACTIVE;
517 Threads_AddActive( new );
523 * \fn Uint Proc_MakeUserStack()
524 * \brief Creates a new user stack
526 Uint Proc_MakeUserStack()
529 Uint base = USER_STACK_TOP - USER_STACK_SZ;
531 // Check Prospective Space
532 for( i = USER_STACK_SZ >> 12; i--; )
533 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
536 if(i != -1) return 0;
538 // Allocate Stack - Allocate incrementally to clean up MM_Dump output
539 for( i = 0; i < USER_STACK_SZ/4069; i++ )
540 MM_Allocate( base + (i<<12) );
542 return base + USER_STACK_SZ;
547 * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
548 * \brief Starts a user task
550 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
552 Uint *stack = (void*)Proc_MakeUserStack();
557 LOG("stack = 0x%x", stack);
560 stack = (void*)( (Uint)stack - DataSize );
561 memcpy( stack, ArgV, DataSize );
563 // Adjust Arguments and environment
564 delta = (Uint)stack - (Uint)ArgV;
565 ArgV = (char**)stack;
566 for( i = 0; ArgV[i]; i++ ) ArgV[i] += delta;
569 for( i = 0; EnvP[i]; i++ ) EnvP[i] += delta;
571 // User Mode Segments
572 ss = 0x23; cs = 0x1B;
575 *--stack = (Uint)EnvP;
576 *--stack = (Uint)ArgV;
577 *--stack = (Uint)ArgC;
580 *--stack = 0; // Return Address
581 delta = (Uint)stack; // Reuse delta to save SP
583 *--stack = ss; //Stack Segment
584 *--stack = delta; //Stack Pointer
585 *--stack = 0x0202; //EFLAGS (Resvd (0x2) and IF (0x20))
586 *--stack = cs; //Code Segment
587 *--stack = Entrypoint; //EIP
589 *--stack = 0xAAAAAAAA; // eax
590 *--stack = 0xCCCCCCCC; // ecx
591 *--stack = 0xDDDDDDDD; // edx
592 *--stack = 0xBBBBBBBB; // ebx
593 *--stack = 0xD1D1D1D1; // edi
594 *--stack = 0x54545454; // esp - NOT POPED
595 *--stack = 0x51515151; // esi
596 *--stack = 0xB4B4B4B4; // ebp
603 __asm__ __volatile__ (
604 "mov %%eax,%%esp;\n\t" // Set stack pointer
610 "iret;\n\t" : : "a" (stack));
615 * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
616 * \brief Demotes a process to a lower permission level
617 * \param Err Pointer to user's errno
618 * \param Dest New Permission Level
619 * \param Regs Pointer to user's register structure
621 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
623 int cpl = Regs->cs & 3;
625 if(Dest > 3 || Dest < 0) {
636 // Change the Segment Registers
637 Regs->cs = (((Dest+1)<<4) | Dest) - 8;
638 Regs->ss = ((Dest+1)<<4) | Dest;
639 // Check if the GP Segs are GDT, then change them
640 if(!(Regs->ds & 4)) Regs->ds = ((Dest+1)<<4) | Dest;
641 if(!(Regs->es & 4)) Regs->es = ((Dest+1)<<4) | Dest;
642 if(!(Regs->fs & 4)) Regs->fs = ((Dest+1)<<4) | Dest;
643 if(!(Regs->gs & 4)) Regs->gs = ((Dest+1)<<4) | Dest;
649 * \fn void Proc_Scheduler(int CPU)
650 * \brief Swap current thread and clears dead threads
652 void Proc_Scheduler(int CPU)
657 // If the spinlock is set, let it complete
658 if(giThreadListLock) return;
660 // Clear Delete Queue
661 while(gDeleteThreads)
663 thread = gDeleteThreads->Next;
664 if(gDeleteThreads->IsLocked) { // Only free if structure is unused
665 gDeleteThreads->Status = THREAD_STAT_NULL;
666 free( gDeleteThreads );
668 gDeleteThreads = thread;
671 // Check if there is any tasks running
672 if(giNumActiveThreads == 0) {
673 Log("No Active threads, sleeping");
674 __asm__ __volatile__ ("hlt");
678 // Get current thread
680 thread = gaCPUs[CPU].Current;
682 curThread = gCurrentThread;
685 // Reduce remaining quantum and continue timeslice if non-zero
686 if(thread->Remaining--) return;
687 // Reset quantum for next call
688 thread->Remaining = thread->Quantum;
691 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
692 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
694 if(eip == SWITCH_MAGIC) return; // Check if a switch happened
696 // Save machine state
697 thread->SavedState.ESP = esp;
698 thread->SavedState.EBP = ebp;
699 thread->SavedState.EIP = eip;
702 thread = Threads_GetNextToRun(CPU);
706 Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
710 #if DEBUG_TRACE_SWITCH
711 Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
713 thread->MemState.CR3,
714 thread->SavedState.EIP
718 // Set current thread
720 gaCPUs[CPU].Current = thread;
722 gCurrentThread = thread;
725 // Update Kernel Stack pointer
726 gTSSs[CPU].ESP0 = thread->KernelStack;
730 # error "Todo: Implement PAE Address space switching"
732 __asm__ __volatile__ ("mov %0, %%cr3"::"a"(thread->MemState.CR3));
735 __asm__ __volatile__ (
736 "mov %1, %%esp\n\t" // Restore ESP
737 "mov %2, %%ebp\n\t" // and EBP
738 "jmp *%3" : : // And return to where we saved state (Proc_Clone or Proc_Scheduler)
739 "a"(SWITCH_MAGIC), "b"(thread->SavedState.ESP),
740 "d"(thread->SavedState.EBP), "c"(thread->SavedState.EIP)
742 for(;;); // Shouldn't reach here
746 EXPORT(Proc_SpawnWorker);