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 tAPIC *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);
180 if( !(ents->Proc.CPUFlags & 1) ) {
185 // Check if there is too many processors
186 if(giNumCPUs >= MAX_CPUS) {
187 giNumCPUs ++; // If `giNumCPUs` > MAX_CPUS later, it will be clipped
191 // Initialise CPU Info
192 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
193 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
194 gaCPUs[giNumCPUs].State = 0;
198 if( !(ents->Proc.CPUFlags & 2) )
200 MP_StartAP( giNumCPUs-1 );
207 Log("\t.ID = %i", ents->Bus.ID);
208 Log("\t.TypeString = '%6c'", ents->Bus.TypeString);
212 Log("%i: I/O APIC", i);
213 Log("\t.ID = %i", ents->IOAPIC.ID);
214 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
215 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
216 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
218 case 3: // I/O Interrupt Assignment
220 Log("%i: I/O Interrupt Assignment", i);
221 Log("\t.IntType = %i", ents->IOInt.IntType);
222 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
223 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
224 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
225 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
226 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
228 case 4: // Local Interrupt Assignment
230 Log("%i: Local Interrupt Assignment", i);
231 Log("\t.IntType = %i", ents->LocalInt.IntType);
232 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
233 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
234 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
235 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
236 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
239 Log("%i: Unknown (%i)", i, ents->Type);
242 ents = (void*)( (Uint)ents + entSize );
245 if( giNumCPUs > MAX_CPUS ) {
246 Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
249 Panic("Uh oh... MP Table Parsing is unimplemented\n");
252 Log("No MP Table was found, assuming uniprocessor\n");
261 // Initialise Double Fault TSS
263 gGDT[5].LimitLow = sizeof(tTSS);
265 gGDT[5].Access = 0x89; // Type
268 gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
269 gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
270 gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
273 // Initialise Normal TSS(s)
274 for(pos=0;pos<giNumCPUs;pos++)
279 gTSSs[pos].SS0 = 0x10;
280 gTSSs[pos].ESP0 = 0; // Set properly by scheduler
281 gGDT[6+pos].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
282 gGDT[6+pos].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
283 gGDT[6+pos].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
286 for(pos=0;pos<giNumCPUs;pos++) {
288 __asm__ __volatile__ ("ltr %%ax"::"a"(0x30+pos*8));
294 gaCPUs[0].Current = &gThreadZero;
296 gCurrentThread = &gThreadZero;
300 gThreadZero.MemState.PDP[0] = 0;
301 gThreadZero.MemState.PDP[1] = 0;
302 gThreadZero.MemState.PDP[2] = 0;
304 gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
307 // Set timer frequency
308 outb(0x43, 0x34); // Set Channel 0, Low/High, Rate Generator
309 outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
310 outb(0x40, (TIMER_DIVISOR>>8)&0xFF); // High Byte
312 // Create Per-Process Data Block
313 MM_Allocate(MM_PPD_CFG);
320 void MP_StartAP(int CPU)
322 Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
323 // Set location of AP startup code and mark for a warm restart
324 *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);
325 *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
326 outb(0x70, 0x0F); outb(0x71, 0x0A); // Warm Reset
327 MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);
330 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
332 Uint32 addr = (Uint)gpMP_LocalAPIC + 0x300;
336 val = (Uint)APICID << 24;
337 Log("*%p = 0x%08x", addr+0x10, val);
338 *(Uint32*)(addr+0x10) = val;
340 val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
341 Log("*%p = 0x%08x", addr, val);
342 *(Uint32*)addr = val;
347 * \fn void Proc_Start()
348 * \brief Start process scheduler
352 // Start Interrupts (and hence scheduler)
353 __asm__ __volatile__("sti");
357 * \fn tThread *Proc_GetCurThread()
358 * \brief Gets the current thread
360 tThread *Proc_GetCurThread()
363 return gaCPUs[ gaAPIC_to_CPU[gpMP_LocalAPIC->ID.Val&0xFF] ].Current;
365 return gCurrentThread;
370 * \fn void Proc_ChangeStack()
371 * \brief Swaps the current stack for a new one (in the proper stack reigon)
373 void Proc_ChangeStack()
377 Uint curBase, newBase;
379 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
380 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
385 newBase = MM_NewKStack();
388 Panic("What the?? Unable to allocate space for initial kernel stack");
392 curBase = (Uint)&Kernel_Stack_Top;
394 LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
396 // Get ESP as a used size
398 LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
400 memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
401 // Get ESP as an offset in the new stack
404 ebp = newBase - (curBase - ebp);
406 // Repair EBPs & Stack Addresses
407 // Catches arguments also, but may trash stack-address-like values
408 for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
410 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
411 *(Uint*)tmpEbp += newBase - curBase;
414 Proc_GetCurThread()->KernelStack = newBase;
416 __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
417 __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
421 * \fn int Proc_Clone(Uint *Err, Uint Flags)
422 * \brief Clone the current process
424 int Proc_Clone(Uint *Err, Uint Flags)
427 tThread *cur = Proc_GetCurThread();
430 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
431 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
433 newThread = Threads_CloneTCB(Err, Flags);
434 if(!newThread) return -1;
436 // Initialise Memory Space (New Addr space or kernel stack)
437 if(Flags & CLONE_VM) {
438 newThread->MemState.CR3 = MM_Clone();
439 newThread->KernelStack = cur->KernelStack;
441 Uint tmpEbp, oldEsp = esp;
444 newThread->MemState.CR3 = cur->MemState.CR3;
447 newThread->KernelStack = MM_NewKStack();
449 if(newThread->KernelStack == 0) {
454 // Get ESP as a used size
455 esp = cur->KernelStack - esp;
457 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
458 // Get ESP as an offset in the new stack
459 esp = newThread->KernelStack - esp;
461 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
463 // Repair EBPs & Stack Addresses
464 // Catches arguments also, but may trash stack-address-like values
465 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
467 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
468 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
472 // Save core machine state
473 newThread->SavedState.ESP = esp;
474 newThread->SavedState.EBP = ebp;
476 if(eip == SWITCH_MAGIC) {
477 outb(0x20, 0x20); // ACK Timer and return as child
482 newThread->SavedState.EIP = eip;
484 // Lock list and add to active
485 Threads_AddActive(newThread);
487 return newThread->TID;
491 * \fn int Proc_SpawnWorker()
492 * \brief Spawns a new worker thread
494 int Proc_SpawnWorker()
499 cur = Proc_GetCurThread();
502 new = malloc( sizeof(tThread) );
504 Warning("Proc_SpawnWorker - Out of heap space!\n");
507 memcpy(new, &gThreadZero, sizeof(tThread));
509 new->TID = giNextTID++;
510 // Create a new worker stack (in PID0's address space)
511 // The stack is relocated by this code
512 new->KernelStack = MM_NewWorkerStack();
514 // Get ESP and EBP based in the new stack
515 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
516 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
517 esp = new->KernelStack - (cur->KernelStack - esp);
518 ebp = new->KernelStack - (cur->KernelStack - ebp);
520 // Save core machine state
521 new->SavedState.ESP = esp;
522 new->SavedState.EBP = ebp;
524 if(eip == SWITCH_MAGIC) {
525 outb(0x20, 0x20); // ACK Timer and return as child
530 new->SavedState.EIP = eip;
532 new->Status = THREAD_STAT_ACTIVE;
533 Threads_AddActive( new );
539 * \fn Uint Proc_MakeUserStack()
540 * \brief Creates a new user stack
542 Uint Proc_MakeUserStack()
545 Uint base = USER_STACK_TOP - USER_STACK_SZ;
547 // Check Prospective Space
548 for( i = USER_STACK_SZ >> 12; i--; )
549 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
552 if(i != -1) return 0;
554 // Allocate Stack - Allocate incrementally to clean up MM_Dump output
555 for( i = 0; i < USER_STACK_SZ/4069; i++ )
556 MM_Allocate( base + (i<<12) );
558 return base + USER_STACK_SZ;
563 * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
564 * \brief Starts a user task
566 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
568 Uint *stack = (void*)Proc_MakeUserStack();
573 LOG("stack = 0x%x", stack);
576 stack = (void*)( (Uint)stack - DataSize );
577 memcpy( stack, ArgV, DataSize );
579 // Adjust Arguments and environment
580 delta = (Uint)stack - (Uint)ArgV;
581 ArgV = (char**)stack;
582 for( i = 0; ArgV[i]; i++ ) ArgV[i] += delta;
585 for( i = 0; EnvP[i]; i++ ) EnvP[i] += delta;
587 // User Mode Segments
588 ss = 0x23; cs = 0x1B;
591 *--stack = (Uint)EnvP;
592 *--stack = (Uint)ArgV;
593 *--stack = (Uint)ArgC;
596 *--stack = 0; // Return Address
597 delta = (Uint)stack; // Reuse delta to save SP
599 *--stack = ss; //Stack Segment
600 *--stack = delta; //Stack Pointer
601 *--stack = 0x0202; //EFLAGS (Resvd (0x2) and IF (0x20))
602 *--stack = cs; //Code Segment
603 *--stack = Entrypoint; //EIP
605 *--stack = 0xAAAAAAAA; // eax
606 *--stack = 0xCCCCCCCC; // ecx
607 *--stack = 0xDDDDDDDD; // edx
608 *--stack = 0xBBBBBBBB; // ebx
609 *--stack = 0xD1D1D1D1; // edi
610 *--stack = 0x54545454; // esp - NOT POPED
611 *--stack = 0x51515151; // esi
612 *--stack = 0xB4B4B4B4; // ebp
619 __asm__ __volatile__ (
620 "mov %%eax,%%esp;\n\t" // Set stack pointer
626 "iret;\n\t" : : "a" (stack));
631 * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
632 * \brief Demotes a process to a lower permission level
633 * \param Err Pointer to user's errno
634 * \param Dest New Permission Level
635 * \param Regs Pointer to user's register structure
637 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
639 int cpl = Regs->cs & 3;
641 if(Dest > 3 || Dest < 0) {
652 // Change the Segment Registers
653 Regs->cs = (((Dest+1)<<4) | Dest) - 8;
654 Regs->ss = ((Dest+1)<<4) | Dest;
655 // Check if the GP Segs are GDT, then change them
656 if(!(Regs->ds & 4)) Regs->ds = ((Dest+1)<<4) | Dest;
657 if(!(Regs->es & 4)) Regs->es = ((Dest+1)<<4) | Dest;
658 if(!(Regs->fs & 4)) Regs->fs = ((Dest+1)<<4) | Dest;
659 if(!(Regs->gs & 4)) Regs->gs = ((Dest+1)<<4) | Dest;
665 * \fn void Proc_Scheduler(int CPU)
666 * \brief Swap current thread and clears dead threads
668 void Proc_Scheduler(int CPU)
673 // If the spinlock is set, let it complete
674 if(giThreadListLock) return;
676 // Clear Delete Queue
677 while(gDeleteThreads)
679 thread = gDeleteThreads->Next;
680 if(gDeleteThreads->IsLocked) { // Only free if structure is unused
681 gDeleteThreads->Status = THREAD_STAT_NULL;
682 free( gDeleteThreads );
684 gDeleteThreads = thread;
687 // Check if there is any tasks running
688 if(giNumActiveThreads == 0) {
689 Log("No Active threads, sleeping");
690 __asm__ __volatile__ ("hlt");
694 // Get current thread
696 thread = gaCPUs[CPU].Current;
698 thread = gCurrentThread;
701 // Reduce remaining quantum and continue timeslice if non-zero
702 if(thread->Remaining--) return;
703 // Reset quantum for next call
704 thread->Remaining = thread->Quantum;
707 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
708 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
710 if(eip == SWITCH_MAGIC) return; // Check if a switch happened
712 // Save machine state
713 thread->SavedState.ESP = esp;
714 thread->SavedState.EBP = ebp;
715 thread->SavedState.EIP = eip;
718 thread = Threads_GetNextToRun(CPU);
722 Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
726 #if DEBUG_TRACE_SWITCH
727 Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
729 thread->MemState.CR3,
730 thread->SavedState.EIP
734 // Set current thread
736 gaCPUs[CPU].Current = thread;
738 gCurrentThread = thread;
741 // Update Kernel Stack pointer
742 gTSSs[CPU].ESP0 = thread->KernelStack;
746 # error "Todo: Implement PAE Address space switching"
748 __asm__ __volatile__ ("mov %0, %%cr3"::"a"(thread->MemState.CR3));
751 __asm__ __volatile__ (
752 "mov %1, %%esp\n\t" // Restore ESP
753 "mov %2, %%ebp\n\t" // and EBP
754 "jmp *%3" : : // And return to where we saved state (Proc_Clone or Proc_Scheduler)
755 "a"(SWITCH_MAGIC), "b"(thread->SavedState.ESP),
756 "d"(thread->SavedState.EBP), "c"(thread->SavedState.EIP)
758 for(;;); // Shouldn't reach here
762 EXPORT(Proc_SpawnWorker);