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");
117 // Initialise Double Fault TSS
118 gGDT[5].LimitLow = sizeof(tTSS);
120 gGDT[5].Access = 0x89; // Type
122 gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
123 gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
124 gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
127 for(pos=0;pos<giNumCPUs;pos++)
132 gTSSs[pos].SS0 = 0x10;
133 gTSSs[pos].ESP0 = 0; // Set properly by scheduler
134 gGDT[6+pos].LimitLow = sizeof(tTSS);
135 gGDT[6+pos].LimitHi = 0;
136 gGDT[6+pos].Access = 0x89; // Type
137 gGDT[6+pos].Flags = 0x4;
138 gGDT[6+pos].BaseLow = (Uint)&gTSSs[pos] & 0xFFFF;
139 gGDT[6+pos].BaseMid = (Uint)&gTSSs[pos] >> 16;
140 gGDT[6+pos].BaseHi = (Uint)&gTSSs[pos] >> 24;
143 for(pos=0;pos<giNumCPUs;pos++) {
145 __asm__ __volatile__ ("ltr %%ax"::"a"(0x30+pos*8));
151 gCurrentThread[0] = &gThreadZero;
153 gCurrentThread = &gThreadZero;
157 gThreadZero.MemState.PDP[0] = 0;
158 gThreadZero.MemState.PDP[1] = 0;
159 gThreadZero.MemState.PDP[2] = 0;
161 gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
164 // Set timer frequency
165 outb(0x43, 0x34); // Set Channel 0, Low/High, Rate Generator
166 outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
167 outb(0x40, (TIMER_DIVISOR>>8)&0xFF); // High Byte
169 // Create Per-Process Data Block
170 MM_Allocate(MM_PPD_CFG);
177 * \fn void Proc_Start()
178 * \brief Start process scheduler
182 // Start Interrupts (and hence scheduler)
183 __asm__ __volatile__("sti");
187 * \fn tThread *Proc_GetCurThread()
188 * \brief Gets the current thread
190 tThread *Proc_GetCurThread()
195 return gCurrentThread;
200 * \fn void Proc_ChangeStack()
201 * \brief Swaps the current stack for a new one (in the proper stack reigon)
203 void Proc_ChangeStack()
207 Uint curBase, newBase;
209 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
210 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
215 newBase = MM_NewKStack();
218 Panic("What the?? Unable to allocate space for initial kernel stack");
222 curBase = (Uint)&Kernel_Stack_Top;
224 LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
226 // Get ESP as a used size
228 LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
230 memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
231 // Get ESP as an offset in the new stack
234 ebp = newBase - (curBase - ebp);
236 // Repair EBPs & Stack Addresses
237 // Catches arguments also, but may trash stack-address-like values
238 for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
240 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
241 *(Uint*)tmpEbp += newBase - curBase;
244 gCurrentThread->KernelStack = newBase;
246 __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
247 __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
251 * \fn int Proc_Clone(Uint *Err, Uint Flags)
252 * \brief Clone the current process
254 int Proc_Clone(Uint *Err, Uint Flags)
257 tThread *cur = Proc_GetCurThread();
260 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
261 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
263 newThread = Threads_CloneTCB(Err, Flags);
264 if(!newThread) return -1;
266 // Initialise Memory Space (New Addr space or kernel stack)
267 if(Flags & CLONE_VM) {
268 newThread->MemState.CR3 = MM_Clone();
269 newThread->KernelStack = cur->KernelStack;
271 Uint tmpEbp, oldEsp = esp;
274 newThread->MemState.CR3 = cur->MemState.CR3;
277 newThread->KernelStack = MM_NewKStack();
279 if(newThread->KernelStack == 0) {
284 // Get ESP as a used size
285 esp = cur->KernelStack - esp;
287 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
288 // Get ESP as an offset in the new stack
289 esp = newThread->KernelStack - esp;
291 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
293 // Repair EBPs & Stack Addresses
294 // Catches arguments also, but may trash stack-address-like values
295 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
297 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
298 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
302 // Save core machine state
303 newThread->SavedState.ESP = esp;
304 newThread->SavedState.EBP = ebp;
306 if(eip == SWITCH_MAGIC) {
307 outb(0x20, 0x20); // ACK Timer and return as child
312 newThread->SavedState.EIP = eip;
314 // Lock list and add to active
315 Threads_AddActive(newThread);
317 return newThread->TID;
321 * \fn int Proc_SpawnWorker()
322 * \brief Spawns a new worker thread
324 int Proc_SpawnWorker()
329 cur = Proc_GetCurThread();
332 new = malloc( sizeof(tThread) );
334 Warning("Proc_SpawnWorker - Out of heap space!\n");
337 memcpy(new, &gThreadZero, sizeof(tThread));
339 new->TID = giNextTID++;
340 // Create a new worker stack (in PID0's address space)
341 // The stack is relocated by this code
342 new->KernelStack = MM_NewWorkerStack();
344 // Get ESP and EBP based in the new stack
345 __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
346 __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
347 esp = new->KernelStack - (cur->KernelStack - esp);
348 ebp = new->KernelStack - (cur->KernelStack - ebp);
350 // Save core machine state
351 new->SavedState.ESP = esp;
352 new->SavedState.EBP = ebp;
354 if(eip == SWITCH_MAGIC) {
355 outb(0x20, 0x20); // ACK Timer and return as child
360 new->SavedState.EIP = eip;
362 new->Status = THREAD_STAT_ACTIVE;
363 Threads_AddActive( new );
369 * \fn Uint Proc_MakeUserStack()
370 * \brief Creates a new user stack
372 Uint Proc_MakeUserStack()
375 Uint base = USER_STACK_TOP - USER_STACK_SZ;
377 // Check Prospective Space
378 for( i = USER_STACK_SZ >> 12; i--; )
379 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
382 if(i != -1) return 0;
384 // Allocate Stack - Allocate incrementally to clean up MM_Dump output
385 for( i = 0; i < USER_STACK_SZ/4069; i++ )
386 MM_Allocate( base + (i<<12) );
388 return base + USER_STACK_SZ;
393 * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
394 * \brief Starts a user task
396 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
398 Uint *stack = (void*)Proc_MakeUserStack();
403 LOG("stack = 0x%x", stack);
406 stack = (void*)( (Uint)stack - DataSize );
407 memcpy( stack, ArgV, DataSize );
409 // Adjust Arguments and environment
410 delta = (Uint)stack - (Uint)ArgV;
411 ArgV = (char**)stack;
412 for( i = 0; ArgV[i]; i++ ) ArgV[i] += delta;
415 for( i = 0; EnvP[i]; i++ ) EnvP[i] += delta;
417 // User Mode Segments
418 ss = 0x23; cs = 0x1B;
421 *--stack = (Uint)EnvP;
422 *--stack = (Uint)ArgV;
423 *--stack = (Uint)ArgC;
426 *--stack = 0; // Return Address
427 delta = (Uint)stack; // Reuse delta to save SP
429 *--stack = ss; //Stack Segment
430 *--stack = delta; //Stack Pointer
431 *--stack = 0x0202; //EFLAGS (Resvd (0x2) and IF (0x20))
432 *--stack = cs; //Code Segment
433 *--stack = Entrypoint; //EIP
435 *--stack = 0xAAAAAAAA; // eax
436 *--stack = 0xCCCCCCCC; // ecx
437 *--stack = 0xDDDDDDDD; // edx
438 *--stack = 0xBBBBBBBB; // ebx
439 *--stack = 0xD1D1D1D1; // edi
440 *--stack = 0x54545454; // esp - NOT POPED
441 *--stack = 0x51515151; // esi
442 *--stack = 0xB4B4B4B4; // ebp
449 __asm__ __volatile__ (
450 "mov %%eax,%%esp;\n\t" // Set stack pointer
456 "iret;\n\t" : : "a" (stack));
461 * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
462 * \brief Demotes a process to a lower permission level
463 * \param Err Pointer to user's errno
464 * \param Dest New Permission Level
465 * \param Regs Pointer to user's register structure
467 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
469 int cpl = Regs->cs & 3;
471 if(Dest > 3 || Dest < 0) {
482 // Change the Segment Registers
483 Regs->cs = (((Dest+1)<<4) | Dest) - 8;
484 Regs->ss = ((Dest+1)<<4) | Dest;
485 // Check if the GP Segs are GDT, then change them
486 if(!(Regs->ds & 4)) Regs->ds = ((Dest+1)<<4) | Dest;
487 if(!(Regs->es & 4)) Regs->es = ((Dest+1)<<4) | Dest;
488 if(!(Regs->fs & 4)) Regs->fs = ((Dest+1)<<4) | Dest;
489 if(!(Regs->gs & 4)) Regs->gs = ((Dest+1)<<4) | Dest;
495 * \fn void Proc_Scheduler(int CPU)
496 * \brief Swap current thread and clears dead threads
498 void Proc_Scheduler(int CPU)
503 // If the spinlock is set, let it complete
504 if(giThreadListLock) return;
506 // Clear Delete Queue
507 while(gDeleteThreads)
509 thread = gDeleteThreads->Next;
510 if(gDeleteThreads->IsLocked) { // Only free if structure is unused
511 gDeleteThreads->Status = THREAD_STAT_NULL;
512 free( gDeleteThreads );
514 gDeleteThreads = thread;
517 // Check if there is any tasks running
518 if(giNumActiveThreads == 0) {
519 Log("No Active threads, sleeping");
520 __asm__ __volatile__ ("hlt");
524 // Reduce remaining quantum and continue timeslice if non-zero
525 if(gCurrentThread->Remaining--) return;
526 // Reset quantum for next call
527 gCurrentThread->Remaining = gCurrentThread->Quantum;
530 __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
531 __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
533 if(eip == SWITCH_MAGIC) return; // Check if a switch happened
535 // Save machine state
536 gCurrentThread->SavedState.ESP = esp;
537 gCurrentThread->SavedState.EBP = ebp;
538 gCurrentThread->SavedState.EIP = eip;
541 thread = Threads_GetNextToRun(CPU);
545 Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
549 #if DEBUG_TRACE_SWITCH
550 Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
552 thread->MemState.CR3,
553 thread->SavedState.EIP
557 // Set current thread
558 gCurrentThread = thread;
560 // Update Kernel Stack pointer
561 gTSSs[CPU].ESP0 = thread->KernelStack;
564 if( gCurrentThread->MemState.CR3 != 0 )
565 __asm__ __volatile__ ("mov %0, %%cr3"::"a"(gCurrentThread->MemState.CR3));
567 __asm__ __volatile__ (
568 "mov %1, %%esp\n\t" // Restore ESP
569 "mov %2, %%ebp\n\t" // and EBP
570 "jmp *%3" : : // And return to where we saved state (Proc_Clone or Proc_Scheduler)
571 "a"(SWITCH_MAGIC), "b"(gCurrentThread->SavedState.ESP),
572 "d"(gCurrentThread->SavedState.EBP), "c"(gCurrentThread->SavedState.EIP)
574 for(;;); // Shouldn't reach here
578 EXPORT(Proc_SpawnWorker);