2 * AcessOS Microkernel Version
14 #define DEBUG_TRACE_SWITCH 0
17 #define SWITCH_MAGIC 0xFFFACE55 // There is no code in this area
19 #define TIMER_DIVISOR 11931 //~100Hz
23 extern void APStartup(); // 16-bit AP startup code
24 extern Uint GetEIP(); // start.asm
25 extern Uint32 gaInitPageDir[1024]; // start.asm
26 extern void Kernel_Stack_Top;
27 extern volatile int giThreadListLock;
30 extern int giTotalTickets;
31 extern int giNumActiveThreads;
32 extern tThread gThreadZero;
33 extern tThread *gActiveThreads;
34 extern tThread *gSleepingThreads;
35 extern tThread *gDeleteThreads;
36 extern tThread *Threads_GetNextToRun(int CPU);
37 extern void Threads_Dump();
38 extern tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
42 void ArchThreads_Init();
44 void MP_StartAP(int CPU);
45 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode);
48 tThread *Proc_GetCurThread();
49 void Proc_ChangeStack();
50 int Proc_Clone(Uint *Err, Uint Flags);
51 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
52 void Proc_Scheduler();
55 // --- Multiprocessing ---
57 volatile int giNumInitingCPUs = 0;
58 tMPInfo *gMPFloatPtr = NULL;
59 tAPIC *gpMP_LocalAPIC = NULL;
60 Uint8 gaAPIC_to_CPU[256] = {0};
61 tCPU gaCPUs[MAX_CPUS];
63 tThread *gCurrentThread = NULL;
66 Uint32 *gPML4s[4] = NULL;
70 // --- Error Recovery ---
71 char gaDoubleFaultStack[1024];
72 tTSS gDoubleFault_TSS = {
73 .ESP0 = (Uint)&gaDoubleFaultStack[1023],
80 * \fn void ArchThreads_Init()
81 * \brief Starts the process scheduler
83 void ArchThreads_Init()
93 // -- Initialise Multiprocessing
94 // Find MP Floating Table
95 // - EBDA/Last 1Kib (640KiB)
96 for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
97 if( *(Uint*)(pos) == MPPTR_IDENT ) {
98 Log("Possible %p", pos);
99 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
100 gMPFloatPtr = (void*)pos;
104 // - Last KiB (512KiB base mem)
106 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
107 if( *(Uint*)(pos) == MPPTR_IDENT ) {
108 Log("Possible %p", pos);
109 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
110 gMPFloatPtr = (void*)pos;
117 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
118 if( *(Uint*)(pos) == MPPTR_IDENT ) {
119 Log("Possible %p", pos);
120 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
121 gMPFloatPtr = (void*)pos;
127 // If the MP Table Exists, parse it
132 Log("gMPFloatPtr = %p", gMPFloatPtr);
133 Log("*gMPFloatPtr = {");
134 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
135 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
136 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
137 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
138 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
139 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
140 gMPFloatPtr->Features[0], gMPFloatPtr->Features[1],
141 gMPFloatPtr->Features[2], gMPFloatPtr->Features[3],
142 gMPFloatPtr->Features[4]
146 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
147 Log("mptable = %p", mptable);
149 Log("\t.Sig = 0x%08x", mptable->Sig);
150 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
151 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
152 Log("\t.Checksum = 0x%02x", mptable->Checksum);
153 Log("\t.OEMID = '%8c'", mptable->OemID);
154 Log("\t.ProductID = '%8c'", mptable->ProductID);
155 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
156 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
157 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
158 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
159 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
160 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
163 gpMP_LocalAPIC = (void*)MM_MapHWPage(mptable->LocalAPICMemMap, 1);
165 ents = mptable->Entries;
168 for( i = 0; i < mptable->EntryCount; i ++ )
175 Log("%i: Processor", i);
176 Log("\t.APICID = %i", ents->Proc.APICID);
177 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
178 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
179 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
180 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
183 if( !(ents->Proc.CPUFlags & 1) ) {
188 // Check if there is too many processors
189 if(giNumCPUs >= MAX_CPUS) {
190 giNumCPUs ++; // If `giNumCPUs` > MAX_CPUS later, it will be clipped
194 // Initialise CPU Info
195 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
196 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
197 gaCPUs[giNumCPUs].State = 0;
201 if( !(ents->Proc.CPUFlags & 2) )
203 MP_StartAP( giNumCPUs-1 );
210 Log("\t.ID = %i", ents->Bus.ID);
211 Log("\t.TypeString = '%6c'", ents->Bus.TypeString);
215 Log("%i: I/O APIC", i);
216 Log("\t.ID = %i", ents->IOAPIC.ID);
217 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
218 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
219 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
221 case 3: // I/O Interrupt Assignment
223 Log("%i: I/O Interrupt Assignment", i);
224 Log("\t.IntType = %i", ents->IOInt.IntType);
225 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
226 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
227 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
228 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
229 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
231 case 4: // Local Interrupt Assignment
233 Log("%i: Local Interrupt Assignment", i);
234 Log("\t.IntType = %i", ents->LocalInt.IntType);
235 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
236 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
237 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
238 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
239 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
242 Log("%i: Unknown (%i)", i, ents->Type);
245 ents = (void*)( (Uint)ents + entSize );
248 if( giNumCPUs > MAX_CPUS ) {
249 Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
250 giNumCPUs = MAX_CPUS;
253 while( giNumInitingCPUs )
254 MM_FinishVirtualInit();
256 Panic("Uh oh... MP Table Parsing is unimplemented\n");
259 Log("No MP Table was found, assuming uniprocessor\n");
266 MM_FinishVirtualInit();
269 // Initialise Double Fault TSS
271 gGDT[5].LimitLow = sizeof(tTSS);
273 gGDT[5].Access = 0x89; // Type
276 gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
277 gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
278 gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
281 // Initialise Normal TSS(s)
282 for(pos=0;pos<giNumCPUs;pos++)
287 gTSSs[pos].SS0 = 0x10;
288 gTSSs[pos].ESP0 = 0; // Set properly by scheduler
289 gGDT[6+pos].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
290 gGDT[6+pos].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
291 gGDT[6+pos].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
294 for(pos=0;pos<giNumCPUs;pos++) {
296 __asm__ __volatile__ ("ltr %%ax"::"a"(0x30+pos*8));
302 gaCPUs[0].Current = &gThreadZero;
304 gCurrentThread = &gThreadZero;
308 gThreadZero.MemState.PDP[0] = 0;
309 gThreadZero.MemState.PDP[1] = 0;
310 gThreadZero.MemState.PDP[2] = 0;
312 gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
315 // Set timer frequency
316 outb(0x43, 0x34); // Set Channel 0, Low/High, Rate Generator
317 outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
318 outb(0x40, (TIMER_DIVISOR>>8)&0xFF); // High Byte
320 // Create Per-Process Data Block
321 MM_Allocate(MM_PPD_CFG);
328 void MP_StartAP(int CPU)
330 Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
331 // Set location of AP startup code and mark for a warm restart
332 *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);
333 *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
334 outb(0x70, 0x0F); outb(0x71, 0x0A); // Warm Reset
335 MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);
339 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
341 Uint32 addr = (Uint)gpMP_LocalAPIC + 0x300;
345 val = (Uint)APICID << 24;
346 Log("*%p = 0x%08x", addr+0x10, val);
347 *(Uint32*)(addr+0x10) = val;
349 val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
350 Log("*%p = 0x%08x", addr, val);
351 *(Uint32*)addr = val;
356 * \fn void Proc_Start()
357 * \brief Start process scheduler
361 // Start Interrupts (and hence scheduler)
362 __asm__ __volatile__("sti");
366 * \fn tThread *Proc_GetCurThread()
367 * \brief Gets the current thread
369 tThread *Proc_GetCurThread()
372 return gaCPUs[ gaAPIC_to_CPU[gpMP_LocalAPIC->ID.Val&0xFF] ].Current;
374 return gCurrentThread;
379 * \fn void Proc_ChangeStack()
380 * \brief Swaps the current stack for a new one (in the proper stack reigon)
382 void Proc_ChangeStack()
386 Uint curBase, newBase;
388 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
389 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
394 newBase = MM_NewKStack();
397 Panic("What the?? Unable to allocate space for initial kernel stack");
401 curBase = (Uint)&Kernel_Stack_Top;
403 LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
405 // Get ESP as a used size
407 LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
409 memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
410 // Get ESP as an offset in the new stack
413 ebp = newBase - (curBase - ebp);
415 // Repair EBPs & Stack Addresses
416 // Catches arguments also, but may trash stack-address-like values
417 for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
419 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
420 *(Uint*)tmpEbp += newBase - curBase;
423 Proc_GetCurThread()->KernelStack = newBase;
425 __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
426 __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
430 * \fn int Proc_Clone(Uint *Err, Uint Flags)
431 * \brief Clone the current process
433 int Proc_Clone(Uint *Err, Uint Flags)
436 tThread *cur = Proc_GetCurThread();
439 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
440 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
442 newThread = Threads_CloneTCB(Err, Flags);
443 if(!newThread) return -1;
445 // Initialise Memory Space (New Addr space or kernel stack)
446 if(Flags & CLONE_VM) {
447 newThread->MemState.CR3 = MM_Clone();
448 newThread->KernelStack = cur->KernelStack;
450 Uint tmpEbp, oldEsp = esp;
453 newThread->MemState.CR3 = cur->MemState.CR3;
456 newThread->KernelStack = MM_NewKStack();
458 if(newThread->KernelStack == 0) {
463 // Get ESP as a used size
464 esp = cur->KernelStack - esp;
466 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
467 // Get ESP as an offset in the new stack
468 esp = newThread->KernelStack - esp;
470 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
472 // Repair EBPs & Stack Addresses
473 // Catches arguments also, but may trash stack-address-like values
474 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
476 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
477 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
481 // Save core machine state
482 newThread->SavedState.ESP = esp;
483 newThread->SavedState.EBP = ebp;
485 if(eip == SWITCH_MAGIC) {
486 outb(0x20, 0x20); // ACK Timer and return as child
491 newThread->SavedState.EIP = eip;
493 // Lock list and add to active
494 Threads_AddActive(newThread);
496 return newThread->TID;
500 * \fn int Proc_SpawnWorker()
501 * \brief Spawns a new worker thread
503 int Proc_SpawnWorker()
508 cur = Proc_GetCurThread();
511 new = malloc( sizeof(tThread) );
513 Warning("Proc_SpawnWorker - Out of heap space!\n");
516 memcpy(new, &gThreadZero, sizeof(tThread));
518 new->TID = giNextTID++;
519 // Create a new worker stack (in PID0's address space)
520 // The stack is relocated by this code
521 new->KernelStack = MM_NewWorkerStack();
523 // Get ESP and EBP based in the new stack
524 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
525 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
526 esp = new->KernelStack - (cur->KernelStack - esp);
527 ebp = new->KernelStack - (cur->KernelStack - ebp);
529 // Save core machine state
530 new->SavedState.ESP = esp;
531 new->SavedState.EBP = ebp;
533 if(eip == SWITCH_MAGIC) {
534 outb(0x20, 0x20); // ACK Timer and return as child
539 new->SavedState.EIP = eip;
541 new->Status = THREAD_STAT_ACTIVE;
542 Threads_AddActive( new );
548 * \fn Uint Proc_MakeUserStack()
549 * \brief Creates a new user stack
551 Uint Proc_MakeUserStack()
554 Uint base = USER_STACK_TOP - USER_STACK_SZ;
556 // Check Prospective Space
557 for( i = USER_STACK_SZ >> 12; i--; )
558 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
561 if(i != -1) return 0;
563 // Allocate Stack - Allocate incrementally to clean up MM_Dump output
564 for( i = 0; i < USER_STACK_SZ/4069; i++ )
565 MM_Allocate( base + (i<<12) );
567 return base + USER_STACK_SZ;
572 * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
573 * \brief Starts a user task
575 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
577 Uint *stack = (void*)Proc_MakeUserStack();
582 LOG("stack = 0x%x", stack);
585 stack = (void*)( (Uint)stack - DataSize );
586 memcpy( stack, ArgV, DataSize );
588 // Adjust Arguments and environment
589 delta = (Uint)stack - (Uint)ArgV;
590 ArgV = (char**)stack;
591 for( i = 0; ArgV[i]; i++ ) ArgV[i] += delta;
594 for( i = 0; EnvP[i]; i++ ) EnvP[i] += delta;
596 // User Mode Segments
597 ss = 0x23; cs = 0x1B;
600 *--stack = (Uint)EnvP;
601 *--stack = (Uint)ArgV;
602 *--stack = (Uint)ArgC;
605 *--stack = 0; // Return Address
607 Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
610 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
612 Uint *stack = (void*)Stack;
613 *--stack = SS; //Stack Segment
614 *--stack = Stack; //Stack Pointer
615 *--stack = Flags; //EFLAGS (Resvd (0x2) and IF (0x20))
616 *--stack = CS; //Code Segment
619 *--stack = 0xAAAAAAAA; // eax
620 *--stack = 0xCCCCCCCC; // ecx
621 *--stack = 0xDDDDDDDD; // edx
622 *--stack = 0xBBBBBBBB; // ebx
623 *--stack = 0xD1D1D1D1; // edi
624 *--stack = 0x54545454; // esp - NOT POPED
625 *--stack = 0x51515151; // esi
626 *--stack = 0xB4B4B4B4; // ebp
633 __asm__ __volatile__ (
634 "mov %%eax,%%esp;\n\t" // Set stack pointer
640 "iret;\n\t" : : "a" (stack));
645 * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
646 * \brief Demotes a process to a lower permission level
647 * \param Err Pointer to user's errno
648 * \param Dest New Permission Level
649 * \param Regs Pointer to user's register structure
651 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
653 int cpl = Regs->cs & 3;
655 if(Dest > 3 || Dest < 0) {
666 // Change the Segment Registers
667 Regs->cs = (((Dest+1)<<4) | Dest) - 8;
668 Regs->ss = ((Dest+1)<<4) | Dest;
669 // Check if the GP Segs are GDT, then change them
670 if(!(Regs->ds & 4)) Regs->ds = ((Dest+1)<<4) | Dest;
671 if(!(Regs->es & 4)) Regs->es = ((Dest+1)<<4) | Dest;
672 if(!(Regs->fs & 4)) Regs->fs = ((Dest+1)<<4) | Dest;
673 if(!(Regs->gs & 4)) Regs->gs = ((Dest+1)<<4) | Dest;
679 * \fn void Proc_Scheduler(int CPU)
680 * \brief Swap current thread and clears dead threads
682 void Proc_Scheduler(int CPU)
687 // If the spinlock is set, let it complete
688 if(giThreadListLock) return;
690 // Clear Delete Queue
691 while(gDeleteThreads)
693 thread = gDeleteThreads->Next;
694 if(gDeleteThreads->IsLocked) { // Only free if structure is unused
695 gDeleteThreads->Status = THREAD_STAT_NULL;
696 free( gDeleteThreads );
698 gDeleteThreads = thread;
701 // Check if there is any tasks running
702 if(giNumActiveThreads == 0) {
703 Log("No Active threads, sleeping");
704 __asm__ __volatile__ ("hlt");
708 // Get current thread
710 thread = gaCPUs[CPU].Current;
712 thread = gCurrentThread;
715 // Reduce remaining quantum and continue timeslice if non-zero
716 if(thread->Remaining--) return;
717 // Reset quantum for next call
718 thread->Remaining = thread->Quantum;
721 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
722 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
724 if(eip == SWITCH_MAGIC) return; // Check if a switch happened
726 // Save machine state
727 thread->SavedState.ESP = esp;
728 thread->SavedState.EBP = ebp;
729 thread->SavedState.EIP = eip;
732 thread = Threads_GetNextToRun(CPU);
736 Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
740 #if DEBUG_TRACE_SWITCH
741 Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
743 thread->MemState.CR3,
744 thread->SavedState.EIP
748 // Set current thread
750 gaCPUs[CPU].Current = thread;
752 gCurrentThread = thread;
755 // Update Kernel Stack pointer
756 gTSSs[CPU].ESP0 = thread->KernelStack-4;
760 # error "Todo: Implement PAE Address space switching"
762 __asm__ __volatile__ ("mov %0, %%cr3"::"a"(thread->MemState.CR3));
765 __asm__ __volatile__ (
766 "mov %1, %%esp\n\t" // Restore ESP
767 "mov %2, %%ebp\n\t" // and EBP
768 "jmp *%3" : : // And return to where we saved state (Proc_Clone or Proc_Scheduler)
769 "a"(SWITCH_MAGIC), "b"(thread->SavedState.ESP),
770 "d"(thread->SavedState.EBP), "c"(thread->SavedState.EIP)
772 for(;;); // Shouldn't reach here
776 EXPORT(Proc_SpawnWorker);