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 Uint GetEIP(); // start.asm
23 extern Uint32 gaInitPageDir[1024]; // start.asm
24 extern void Kernel_Stack_Top;
25 extern volatile int giThreadListLock;
28 extern int giTotalTickets;
29 extern int giNumActiveThreads;
30 extern tThread gThreadZero;
31 extern tThread *gActiveThreads;
32 extern tThread *gSleepingThreads;
33 extern tThread *gDeleteThreads;
34 extern tThread *Threads_GetNextToRun(int CPU);
35 extern void Threads_Dump();
36 extern tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
40 void ArchThreads_Init();
41 tThread *Proc_GetCurThread();
42 void Proc_ChangeStack();
43 int Proc_Clone(Uint *Err, Uint Flags);
44 void Proc_Scheduler();
47 // --- Current State ---
49 tThread *gCurrentThread[MAX_CPUS] = {NULL};
51 tThread *gCurrentThread = NULL;
53 // --- Multiprocessing ---
55 tMPInfo *gMPTable = NULL;
58 Uint32 *gPML4s[4] = NULL;
64 // --- Error Recovery ---
65 char gaDoubleFaultStack[1024];
66 tTSS gDoubleFault_TSS = {
67 .ESP0 = (Uint)&gaDoubleFaultStack[1023],
74 * \fn void ArchThreads_Init()
75 * \brief Starts the process scheduler
77 void ArchThreads_Init()
81 // -- Initialise Multiprocessing
82 // Find MP Floating Table
84 for(pos = KERNEL_BASE|0x9FC00; pos < (KERNEL_BASE|0xA0000); pos += 16) {
85 if( *(Uint*)(pos) == MPTABLE_IDENT ) {
86 if(ByteSum( (void*)pos, sizeof(tMPInfo) ) != 0) continue;
87 gMPTable = (void*)pos;
97 for(pos = KERNEL_BASE|0xF0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
98 if( *(Uint*)(pos) == MPTABLE_IDENT ) {
99 if(ByteSum( (void*)pos, sizeof(tMPInfo) ) != 0) continue;
100 gMPTable = (void*)pos;
106 // If the MP Table Exists, parse it
109 Panic("Uh oh... MP Table Parsing is unimplemented\n");
118 // Initialise Double Fault TSS
119 gGDT[5].LimitLow = sizeof(tTSS);
121 gGDT[5].Access = 0x89; // Type
123 gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
124 gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
125 gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
128 // Initialise Normal TSS(s)
129 for(pos=0;pos<giNumCPUs;pos++)
134 gTSSs[pos].SS0 = 0x10;
135 gTSSs[pos].ESP0 = 0; // Set properly by scheduler
136 gGDT[6+pos].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
137 gGDT[6+pos].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
138 gGDT[6+pos].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
139 gGDT[6+pos].LimitLow = sizeof(tTSS);
140 gGDT[6+pos].LimitHi = 0;
141 gGDT[6+pos].Access = 0x89; // Type
142 gGDT[6+pos].Flags = 0x4;
145 for(pos=0;pos<giNumCPUs;pos++) {
147 __asm__ __volatile__ ("ltr %%ax"::"a"(0x30+pos*8));
153 gCurrentThread[0] = &gThreadZero;
155 gCurrentThread = &gThreadZero;
159 gThreadZero.MemState.PDP[0] = 0;
160 gThreadZero.MemState.PDP[1] = 0;
161 gThreadZero.MemState.PDP[2] = 0;
163 gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
166 // Set timer frequency
167 outb(0x43, 0x34); // Set Channel 0, Low/High, Rate Generator
168 outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
169 outb(0x40, (TIMER_DIVISOR>>8)&0xFF); // High Byte
171 // Create Per-Process Data Block
172 MM_Allocate(MM_PPD_CFG);
179 * \fn void Proc_Start()
180 * \brief Start process scheduler
184 // Start Interrupts (and hence scheduler)
185 __asm__ __volatile__("sti");
189 * \fn tThread *Proc_GetCurThread()
190 * \brief Gets the current thread
192 tThread *Proc_GetCurThread()
197 return gCurrentThread;
202 * \fn void Proc_ChangeStack()
203 * \brief Swaps the current stack for a new one (in the proper stack reigon)
205 void Proc_ChangeStack()
209 Uint curBase, newBase;
211 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
212 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
217 newBase = MM_NewKStack();
220 Panic("What the?? Unable to allocate space for initial kernel stack");
224 curBase = (Uint)&Kernel_Stack_Top;
226 LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
228 // Get ESP as a used size
230 LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
232 memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
233 // Get ESP as an offset in the new stack
236 ebp = newBase - (curBase - ebp);
238 // Repair EBPs & Stack Addresses
239 // Catches arguments also, but may trash stack-address-like values
240 for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
242 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
243 *(Uint*)tmpEbp += newBase - curBase;
246 gCurrentThread->KernelStack = newBase;
248 __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
249 __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
253 * \fn int Proc_Clone(Uint *Err, Uint Flags)
254 * \brief Clone the current process
256 int Proc_Clone(Uint *Err, Uint Flags)
259 tThread *cur = Proc_GetCurThread();
262 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
263 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
265 newThread = Threads_CloneTCB(Err, Flags);
266 if(!newThread) return -1;
268 // Initialise Memory Space (New Addr space or kernel stack)
269 if(Flags & CLONE_VM) {
270 newThread->MemState.CR3 = MM_Clone();
271 newThread->KernelStack = cur->KernelStack;
273 Uint tmpEbp, oldEsp = esp;
276 newThread->MemState.CR3 = cur->MemState.CR3;
279 newThread->KernelStack = MM_NewKStack();
281 if(newThread->KernelStack == 0) {
286 // Get ESP as a used size
287 esp = cur->KernelStack - esp;
289 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
290 // Get ESP as an offset in the new stack
291 esp = newThread->KernelStack - esp;
293 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
295 // Repair EBPs & Stack Addresses
296 // Catches arguments also, but may trash stack-address-like values
297 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
299 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
300 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
304 // Save core machine state
305 newThread->SavedState.ESP = esp;
306 newThread->SavedState.EBP = ebp;
308 if(eip == SWITCH_MAGIC) {
309 outb(0x20, 0x20); // ACK Timer and return as child
314 newThread->SavedState.EIP = eip;
316 // Lock list and add to active
317 Threads_AddActive(newThread);
319 return newThread->TID;
323 * \fn int Proc_SpawnWorker()
324 * \brief Spawns a new worker thread
326 int Proc_SpawnWorker()
331 cur = Proc_GetCurThread();
334 new = malloc( sizeof(tThread) );
336 Warning("Proc_SpawnWorker - Out of heap space!\n");
339 memcpy(new, &gThreadZero, sizeof(tThread));
341 new->TID = giNextTID++;
342 // Create a new worker stack (in PID0's address space)
343 // The stack is relocated by this code
344 new->KernelStack = MM_NewWorkerStack();
346 // Get ESP and EBP based in the new stack
347 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
348 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
349 esp = new->KernelStack - (cur->KernelStack - esp);
350 ebp = new->KernelStack - (cur->KernelStack - ebp);
352 // Save core machine state
353 new->SavedState.ESP = esp;
354 new->SavedState.EBP = ebp;
356 if(eip == SWITCH_MAGIC) {
357 outb(0x20, 0x20); // ACK Timer and return as child
362 new->SavedState.EIP = eip;
364 new->Status = THREAD_STAT_ACTIVE;
365 Threads_AddActive( new );
371 * \fn Uint Proc_MakeUserStack()
372 * \brief Creates a new user stack
374 Uint Proc_MakeUserStack()
377 Uint base = USER_STACK_TOP - USER_STACK_SZ;
379 // Check Prospective Space
380 for( i = USER_STACK_SZ >> 12; i--; )
381 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
384 if(i != -1) return 0;
386 // Allocate Stack - Allocate incrementally to clean up MM_Dump output
387 for( i = 0; i < USER_STACK_SZ/4069; i++ )
388 MM_Allocate( base + (i<<12) );
390 return base + USER_STACK_SZ;
395 * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
396 * \brief Starts a user task
398 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
400 Uint *stack = (void*)Proc_MakeUserStack();
405 LOG("stack = 0x%x", stack);
408 stack = (void*)( (Uint)stack - DataSize );
409 memcpy( stack, ArgV, DataSize );
411 // Adjust Arguments and environment
412 delta = (Uint)stack - (Uint)ArgV;
413 ArgV = (char**)stack;
414 for( i = 0; ArgV[i]; i++ ) ArgV[i] += delta;
417 for( i = 0; EnvP[i]; i++ ) EnvP[i] += delta;
419 // User Mode Segments
420 ss = 0x23; cs = 0x1B;
423 *--stack = (Uint)EnvP;
424 *--stack = (Uint)ArgV;
425 *--stack = (Uint)ArgC;
428 *--stack = 0; // Return Address
429 delta = (Uint)stack; // Reuse delta to save SP
431 *--stack = ss; //Stack Segment
432 *--stack = delta; //Stack Pointer
433 *--stack = 0x0202; //EFLAGS (Resvd (0x2) and IF (0x20))
434 *--stack = cs; //Code Segment
435 *--stack = Entrypoint; //EIP
437 *--stack = 0xAAAAAAAA; // eax
438 *--stack = 0xCCCCCCCC; // ecx
439 *--stack = 0xDDDDDDDD; // edx
440 *--stack = 0xBBBBBBBB; // ebx
441 *--stack = 0xD1D1D1D1; // edi
442 *--stack = 0x54545454; // esp - NOT POPED
443 *--stack = 0x51515151; // esi
444 *--stack = 0xB4B4B4B4; // ebp
451 __asm__ __volatile__ (
452 "mov %%eax,%%esp;\n\t" // Set stack pointer
458 "iret;\n\t" : : "a" (stack));
463 * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
464 * \brief Demotes a process to a lower permission level
465 * \param Err Pointer to user's errno
466 * \param Dest New Permission Level
467 * \param Regs Pointer to user's register structure
469 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
471 int cpl = Regs->cs & 3;
473 if(Dest > 3 || Dest < 0) {
484 // Change the Segment Registers
485 Regs->cs = (((Dest+1)<<4) | Dest) - 8;
486 Regs->ss = ((Dest+1)<<4) | Dest;
487 // Check if the GP Segs are GDT, then change them
488 if(!(Regs->ds & 4)) Regs->ds = ((Dest+1)<<4) | Dest;
489 if(!(Regs->es & 4)) Regs->es = ((Dest+1)<<4) | Dest;
490 if(!(Regs->fs & 4)) Regs->fs = ((Dest+1)<<4) | Dest;
491 if(!(Regs->gs & 4)) Regs->gs = ((Dest+1)<<4) | Dest;
497 * \fn void Proc_Scheduler(int CPU)
498 * \brief Swap current thread and clears dead threads
500 void Proc_Scheduler(int CPU)
505 // If the spinlock is set, let it complete
506 if(giThreadListLock) return;
508 // Clear Delete Queue
509 while(gDeleteThreads)
511 thread = gDeleteThreads->Next;
512 if(gDeleteThreads->IsLocked) { // Only free if structure is unused
513 gDeleteThreads->Status = THREAD_STAT_NULL;
514 free( gDeleteThreads );
516 gDeleteThreads = thread;
519 // Check if there is any tasks running
520 if(giNumActiveThreads == 0) {
521 Log("No Active threads, sleeping");
522 __asm__ __volatile__ ("hlt");
526 // Reduce remaining quantum and continue timeslice if non-zero
527 if(gCurrentThread->Remaining--) return;
528 // Reset quantum for next call
529 gCurrentThread->Remaining = gCurrentThread->Quantum;
532 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
533 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
535 if(eip == SWITCH_MAGIC) return; // Check if a switch happened
537 // Save machine state
538 gCurrentThread->SavedState.ESP = esp;
539 gCurrentThread->SavedState.EBP = ebp;
540 gCurrentThread->SavedState.EIP = eip;
543 thread = Threads_GetNextToRun(CPU);
547 Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
551 #if DEBUG_TRACE_SWITCH
552 Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
554 thread->MemState.CR3,
555 thread->SavedState.EIP
559 // Set current thread
560 gCurrentThread = thread;
562 // Update Kernel Stack pointer
563 gTSSs[CPU].ESP0 = thread->KernelStack;
566 if( gCurrentThread->MemState.CR3 != 0 )
567 __asm__ __volatile__ ("mov %0, %%cr3"::"a"(gCurrentThread->MemState.CR3));
569 __asm__ __volatile__ (
570 "mov %1, %%esp\n\t" // Restore ESP
571 "mov %2, %%ebp\n\t" // and EBP
572 "jmp *%3" : : // And return to where we saved state (Proc_Clone or Proc_Scheduler)
573 "a"(SWITCH_MAGIC), "b"(gCurrentThread->SavedState.ESP),
574 "d"(gCurrentThread->SavedState.EBP), "c"(gCurrentThread->SavedState.EIP)
576 for(;;); // Shouldn't reach here
580 EXPORT(Proc_SpawnWorker);