Kernel/arch/x86/proc.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * proc.c
   4  */
   5 #include <acess.h>
   6 #include <proc.h>
   7 #include <desctab.h>
   8 #include <mm_virt.h>
   9 #include <errno.h>
  10 #if USE_MP
  11 # include <mp.h>
  12 #endif
  13
  14 // === FLAGS ===
  15 #define DEBUG_TRACE_SWITCH      0
  16
  17 // === CONSTANTS ===
  18 #define SWITCH_MAGIC    0xFFFACE55      // There is no code in this area
  19 // Base is 1193182
  20 #define TIMER_DIVISOR   11931   //~100Hz
  21
  22 // === TYPES ===
  23 #if USE_MP
  24 typedef struct sCPU
  25 {
  26         Uint8   APICID;
  27         Uint8   State;  // 0: Unavaliable, 1: Idle, 2: Active
  28         Uint16  Resvd;
  29         tThread *Current;
  30 }       tCPU;
  31 #endif
  32
  33 // === IMPORTS ===
  34 extern tGDT     gGDT[];
  35 extern tIDT     gIDT[];
  36 extern void APWait(void);       // 16-bit AP pause code
  37 extern void APStartup(void);    // 16-bit AP startup code
  38 extern Uint     GetEIP(void);   // start.asm
  39 extern int      GetCPUNum(void);        // start.asm
  40 extern Uint32   gaInitPageDir[1024];    // start.asm
  41 extern void     Kernel_Stack_Top;
  42 extern tSpinlock        glThreadListLock;
  43 extern int      giNumCPUs;
  44 extern int      giNextTID;
  45 extern int      giTotalTickets;
  46 extern int      giNumActiveThreads;
  47 extern tThread  gThreadZero;
  48 extern tThread  *gActiveThreads;
  49 extern tThread  *gSleepingThreads;
  50 extern tThread  *gDeleteThreads;
  51 extern tThread  *Threads_GetNextToRun(int CPU);
  52 extern void     Threads_Dump(void);
  53 extern tThread  *Threads_CloneTCB(Uint *Err, Uint Flags);
  54 extern void     Isr8(void);     // Double Fault
  55 extern void     Proc_ReturnToUser(void);
  56
  57 // === PROTOTYPES ===
  58 void    ArchThreads_Init(void);
  59 #if USE_MP
  60 void    MP_StartAP(int CPU);
  61 void    MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode);
  62 #endif
  63 void    Proc_Start(void);
  64 tThread *Proc_GetCurThread(void);
  65 void    Proc_ChangeStack(void);
  66  int    Proc_Clone(Uint *Err, Uint Flags);
  67 void    Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
  68 void    Proc_CallFaultHandler(tThread *Thread);
  69 void    Proc_Scheduler(int CPU);
  70
  71 // === GLOBALS ===
  72 // --- Multiprocessing ---
  73 #if USE_MP
  74 volatile int    giNumInitingCPUs = 0;
  75 tMPInfo *gMPFloatPtr = NULL;
  76 tAPIC   *gpMP_LocalAPIC = NULL;
  77 Uint8   gaAPIC_to_CPU[256] = {0};
  78 tCPU    gaCPUs[MAX_CPUS];
  79 tTSS    gaTSSs[MAX_CPUS];       // TSS Array
  80  int    giProc_BootProcessorID = 0;
  81 #else
  82 tThread *gCurrentThread = NULL;
  83 #endif
  84 #if USE_PAE
  85 Uint32  *gPML4s[4] = NULL;
  86 #endif
  87 tTSS    *gTSSs = NULL;  // Pointer to TSS array
  88 tTSS    gTSS0 = {0};
  89 // --- Error Recovery ---
  90 char    gaDoubleFaultStack[1024];
  91 tTSS    gDoubleFault_TSS = {
  92         .ESP0 = (Uint)&gaDoubleFaultStack[1023],
  93         .SS0 = 0x10,
  94         .CR3 = (Uint)gaInitPageDir - KERNEL_BASE,
  95         .EIP = (Uint)Isr8,
  96         .ESP = (Uint)&gaDoubleFaultStack[1023],
  97         .CS = 0x08,     .SS = 0x10,
  98         .DS = 0x10,     .ES = 0x10,
  99         .FS = 0x10,     .GS = 0x10,
 100 };
 101
 102 // === CODE ===
 103 /**
 104  * \fn void ArchThreads_Init(void)
 105  * \brief Starts the process scheduler
 106  */
 107 void ArchThreads_Init(void)
 108 {
 109         Uint    pos = 0;
 110
 111         #if USE_MP
 112         tMPTable        *mptable;
 113
 114         // Mark BSP as active
 115         gaCPUs[0].State = 2;
 116
 117         // -- Initialise Multiprocessing
 118         // Find MP Floating Table
 119         // - EBDA/Last 1Kib (640KiB)
 120         for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
 121                 if( *(Uint*)(pos) == MPPTR_IDENT ) {
 122                         Log("Possible %p", pos);
 123                         if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 124                         gMPFloatPtr = (void*)pos;
 125                         break;
 126                 }
 127         }
 128         // - Last KiB (512KiB base mem)
 129         if(!gMPFloatPtr) {
 130                 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
 131                         if( *(Uint*)(pos) == MPPTR_IDENT ) {
 132                                 Log("Possible %p", pos);
 133                                 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 134                                 gMPFloatPtr = (void*)pos;
 135                                 break;
 136                         }
 137                 }
 138         }
 139         // - BIOS ROM
 140         if(!gMPFloatPtr) {
 141                 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
 142                         if( *(Uint*)(pos) == MPPTR_IDENT ) {
 143                                 Log("Possible %p", pos);
 144                                 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 145                                 gMPFloatPtr = (void*)pos;
 146                                 break;
 147                         }
 148                 }
 149         }
 150
 151         // If the MP Table Exists, parse it
 152         if(gMPFloatPtr)
 153         {
 154                  int    i;
 155                 tMPTable_Ent    *ents;
 156                 Log("gMPFloatPtr = %p", gMPFloatPtr);
 157                 Log("*gMPFloatPtr = {");
 158                 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
 159                 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
 160                 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
 161                 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
 162                 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
 163                 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
 164                         gMPFloatPtr->Features[0],       gMPFloatPtr->Features[1],
 165                         gMPFloatPtr->Features[2],       gMPFloatPtr->Features[3],
 166                         gMPFloatPtr->Features[4]
 167                         );
 168                 Log("}");
 169
 170                 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
 171                 Log("mptable = %p", mptable);
 172                 Log("*mptable = {");
 173                 Log("\t.Sig = 0x%08x", mptable->Sig);
 174                 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
 175                 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
 176                 Log("\t.Checksum = 0x%02x", mptable->Checksum);
 177                 Log("\t.OEMID = '%8c'", mptable->OemID);
 178                 Log("\t.ProductID = '%8c'", mptable->ProductID);
 179                 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
 180                 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
 181                 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
 182                 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
 183                 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
 184                 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
 185                 Log("}");
 186
 187                 gpMP_LocalAPIC = (void*)MM_MapHWPages(mptable->LocalAPICMemMap, 1);
 188
 189                 ents = mptable->Entries;
 190                 giNumCPUs = 0;
 191
 192                 for( i = 0; i < mptable->EntryCount; i ++ )
 193                 {
 194                          int    entSize = 0;
 195                         switch( ents->Type )
 196                         {
 197                         case 0: // Processor
 198                                 entSize = 20;
 199                                 Log("%i: Processor", i);
 200                                 Log("\t.APICID = %i", ents->Proc.APICID);
 201                                 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
 202                                 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
 203                                 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
 204                                 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
 205
 206
 207                                 if( !(ents->Proc.CPUFlags & 1) ) {
 208                                         Log("DISABLED");
 209                                         break;
 210                                 }
 211
 212                                 // Check if there is too many processors
 213                                 if(giNumCPUs >= MAX_CPUS) {
 214                                         giNumCPUs ++;   // If `giNumCPUs` > MAX_CPUS later, it will be clipped
 215                                         break;
 216                                 }
 217
 218                                 // Initialise CPU Info
 219                                 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
 220                                 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
 221                                 gaCPUs[giNumCPUs].State = 0;
 222                                 giNumCPUs ++;
 223
 224                                 // Set BSP Variable
 225                                 if( ents->Proc.CPUFlags & 2 ) {
 226                                         giProc_BootProcessorID = giNumCPUs-1;
 227                                 }
 228
 229                                 break;
 230                         case 1: // Bus
 231                                 entSize = 8;
 232                                 Log("%i: Bus", i);
 233                                 Log("\t.ID = %i", ents->Bus.ID);
 234                                 Log("\t.TypeString = '%6C'", ents->Bus.TypeString);
 235                                 break;
 236                         case 2: // I/O APIC
 237                                 entSize = 8;
 238                                 Log("%i: I/O APIC", i);
 239                                 Log("\t.ID = %i", ents->IOAPIC.ID);
 240                                 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
 241                                 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
 242                                 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
 243                                 break;
 244                         case 3: // I/O Interrupt Assignment
 245                                 entSize = 8;
 246                                 Log("%i: I/O Interrupt Assignment", i);
 247                                 Log("\t.IntType = %i", ents->IOInt.IntType);
 248                                 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
 249                                 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
 250                                 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
 251                                 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
 252                                 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
 253                                 break;
 254                         case 4: // Local Interrupt Assignment
 255                                 entSize = 8;
 256                                 Log("%i: Local Interrupt Assignment", i);
 257                                 Log("\t.IntType = %i", ents->LocalInt.IntType);
 258                                 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
 259                                 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
 260                                 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
 261                                 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
 262                                 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
 263                                 break;
 264                         default:
 265                                 Log("%i: Unknown (%i)", i, ents->Type);
 266                                 break;
 267                         }
 268                         ents = (void*)( (Uint)ents + entSize );
 269                 }
 270
 271                 if( giNumCPUs > MAX_CPUS ) {
 272                         Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
 273                         giNumCPUs = MAX_CPUS;
 274                 }
 275                 gTSSs = gaTSSs;
 276         }
 277         else {
 278                 Log("No MP Table was found, assuming uniprocessor\n");
 279                 giNumCPUs = 1;
 280                 gTSSs = &gTSS0;
 281         }
 282         #else
 283         giNumCPUs = 1;
 284         gTSSs = &gTSS0;
 285         MM_FinishVirtualInit();
 286         #endif
 287
 288         // Initialise Double Fault TSS
 289         gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
 290         gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
 291         gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
 292
 293         // Set double fault IDT to use the new TSS
 294         gIDT[8].OffsetLo = 0;
 295         gIDT[8].CS = 5<<3;
 296         gIDT[8].Flags = 0x8500;
 297         gIDT[8].OffsetHi = 0;
 298
 299         #if USE_MP
 300         // Initialise Normal TSS(s)
 301         for(pos=0;pos<giNumCPUs;pos++)
 302         {
 303         #else
 304         pos = 0;
 305         #endif
 306                 gTSSs[pos].SS0 = 0x10;
 307                 gTSSs[pos].ESP0 = 0;    // Set properly by scheduler
 308                 gGDT[6+pos].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
 309                 gGDT[6+pos].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
 310                 gGDT[6+pos].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
 311         #if USE_MP
 312         }
 313
 314         // Start APs
 315         for( pos = 0; pos < giNumCPUs; pos ++ )
 316         {
 317                 gaCPUs[pos].Current = NULL;
 318                 if( pos != giProc_BootProcessorID ) {
 319                         Log("Starting AP %i, (APIC %i)\n", pos, gaCPUs[pos].APICID);
 320                         MP_StartAP( pos );
 321                 }
 322         }
 323
 324         Log("Waiting for APs to come up\n");
 325         while( giNumInitingCPUs )       __asm__ __volatile__ ("hlt");
 326         MM_FinishVirtualInit();
 327         //Panic("Uh oh... MP Table Parsing is unimplemented\n");
 328         #endif
 329
 330         // Load the BSP's TSS
 331         __asm__ __volatile__ ("ltr %%ax"::"a"(0x30));
 332
 333         #if USE_MP
 334         gaCPUs[0].Current = &gThreadZero;
 335         #else
 336         gCurrentThread = &gThreadZero;
 337         #endif
 338
 339         #if USE_PAE
 340         gThreadZero.MemState.PDP[0] = 0;
 341         gThreadZero.MemState.PDP[1] = 0;
 342         gThreadZero.MemState.PDP[2] = 0;
 343         #else
 344         gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
 345         #endif
 346
 347         // Set timer frequency
 348         outb(0x43, 0x34);       // Set Channel 0, Low/High, Rate Generator
 349         outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
 350         outb(0x40, (TIMER_DIVISOR>>8)&0xFF);    // High Byte
 351
 352         // Create Per-Process Data Block
 353         MM_Allocate(MM_PPD_CFG);
 354
 355         // Change Stacks
 356         Proc_ChangeStack();
 357 }
 358
 359 #if USE_MP
 360 void MP_StartAP(int CPU)
 361 {
 362         Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
 363
 364         // Set location of AP startup code and mark for a warm restart
 365         *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APWait - (KERNEL_BASE|0xFFFF0);
 366         *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
 367         outb(0x70, 0x0F);       outb(0x71, 0x0A);       // Warm Reset
 368         MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);   // Init IPI
 369
 370         // Delay
 371         inb(0x80); inb(0x80); inb(0x80); inb(0x80);
 372
 373         // Create a far jump
 374         *(Uint8*)(KERNEL_BASE|0x11000) = 0xEA;  // Far JMP
 375         *(Uint16*)(KERNEL_BASE|0x11001) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);     // IP
 376         *(Uint16*)(KERNEL_BASE|0x11003) = 0xFFFF;       // CS
 377         // Send a Startup-IPI to make the CPU execute at 0x11000 (which we
 378         // just filled)
 379         MP_SendIPI(gaCPUs[CPU].APICID, 0x11, 6);        // StartupIPI
 380
 381         giNumInitingCPUs ++;
 382 }
 383
 384 /**
 385  * \brief Send an Inter-Processor Interrupt
 386  * \param APICID        Processor's Local APIC ID
 387  * \param Vector        Argument of some kind
 388  * \param DeliveryMode  Type of signal?
 389  */
 390 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
 391 {
 392         Uint32  addr = (Uint)gpMP_LocalAPIC + 0x300;
 393         Uint32  val;
 394
 395         // Hi
 396         val = (Uint)APICID << 24;
 397         Log("*%p = 0x%08x", addr+0x10, val);
 398         *(Uint32*)(addr+0x10) = val;
 399
 400         // Low (and send)
 401         val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
 402         Log("*%p = 0x%08x", addr, val);
 403         *(Uint32*)addr = val;
 404 }
 405 #endif
 406
 407 /**
 408  * \fn void Proc_Start(void)
 409  * \brief Start process scheduler
 410  */
 411 void Proc_Start(void)
 412 {
 413         // Start Interrupts (and hence scheduler)
 414         __asm__ __volatile__("sti");
 415 }
 416
 417 /**
 418  * \fn tThread *Proc_GetCurThread(void)
 419  * \brief Gets the current thread
 420  */
 421 tThread *Proc_GetCurThread(void)
 422 {
 423         #if USE_MP
 424         //return gaCPUs[ gaAPIC_to_CPU[gpMP_LocalAPIC->ID.Val&0xFF] ].Current;
 425         return gaCPUs[ GetCPUNum() ].Current;
 426         #else
 427         return gCurrentThread;
 428         #endif
 429 }
 430
 431 /**
 432  * \fn void Proc_ChangeStack(void)
 433  * \brief Swaps the current stack for a new one (in the proper stack reigon)
 434  */
 435 void Proc_ChangeStack(void)
 436 {
 437         Uint    esp, ebp;
 438         Uint    tmpEbp, oldEsp;
 439         Uint    curBase, newBase;
 440
 441         __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
 442         __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
 443
 444         oldEsp = esp;
 445
 446         // Create new KStack
 447         newBase = MM_NewKStack();
 448         // Check for errors
 449         if(newBase == 0) {
 450                 Panic("What the?? Unable to allocate space for initial kernel stack");
 451                 return;
 452         }
 453
 454         curBase = (Uint)&Kernel_Stack_Top;
 455
 456         LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
 457
 458         // Get ESP as a used size
 459         esp = curBase - esp;
 460         LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
 461         // Copy used stack
 462         memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
 463         // Get ESP as an offset in the new stack
 464         esp = newBase - esp;
 465         // Adjust EBP
 466         ebp = newBase - (curBase - ebp);
 467
 468         // Repair EBPs & Stack Addresses
 469         // Catches arguments also, but may trash stack-address-like values
 470         for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
 471         {
 472                 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
 473                         *(Uint*)tmpEbp += newBase - curBase;
 474         }
 475
 476         Proc_GetCurThread()->KernelStack = newBase;
 477
 478         __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
 479         __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
 480 }
 481
 482 /**
 483  * \fn int Proc_Clone(Uint *Err, Uint Flags)
 484  * \brief Clone the current process
 485  */
 486 int Proc_Clone(Uint *Err, Uint Flags)
 487 {
 488         tThread *newThread;
 489         tThread *cur = Proc_GetCurThread();
 490         Uint    eip, esp, ebp;
 491
 492         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 493         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 494
 495         newThread = Threads_CloneTCB(Err, Flags);
 496         if(!newThread)  return -1;
 497
 498         // Initialise Memory Space (New Addr space or kernel stack)
 499         if(Flags & CLONE_VM) {
 500                 newThread->MemState.CR3 = MM_Clone();
 501                 newThread->KernelStack = cur->KernelStack;
 502         } else {
 503                 Uint    tmpEbp, oldEsp = esp;
 504
 505                 // Set CR3
 506                 newThread->MemState.CR3 = cur->MemState.CR3;
 507
 508                 // Create new KStack
 509                 newThread->KernelStack = MM_NewKStack();
 510                 // Check for errors
 511                 if(newThread->KernelStack == 0) {
 512                         free(newThread);
 513                         return -1;
 514                 }
 515
 516                 // Get ESP as a used size
 517                 esp = cur->KernelStack - esp;
 518                 // Copy used stack
 519                 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
 520                 // Get ESP as an offset in the new stack
 521                 esp = newThread->KernelStack - esp;
 522                 // Adjust EBP
 523                 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
 524
 525                 // Repair EBPs & Stack Addresses
 526                 // Catches arguments also, but may trash stack-address-like values
 527                 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
 528                 {
 529                         if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
 530                                 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
 531                 }
 532         }
 533
 534         // Save core machine state
 535         newThread->SavedState.ESP = esp;
 536         newThread->SavedState.EBP = ebp;
 537         eip = GetEIP();
 538         if(eip == SWITCH_MAGIC) {
 539                 outb(0x20, 0x20);       // ACK Timer and return as child
 540                 return 0;
 541         }
 542
 543         // Set EIP as parent
 544         newThread->SavedState.EIP = eip;
 545
 546         // Lock list and add to active
 547         Threads_AddActive(newThread);
 548
 549         return newThread->TID;
 550 }
 551
 552 /**
 553  * \fn int Proc_SpawnWorker(void)
 554  * \brief Spawns a new worker thread
 555  */
 556 int Proc_SpawnWorker(void)
 557 {
 558         tThread *new, *cur;
 559         Uint    eip, esp, ebp;
 560
 561         cur = Proc_GetCurThread();
 562
 563         // Create new thread
 564         new = malloc( sizeof(tThread) );
 565         if(!new) {
 566                 Warning("Proc_SpawnWorker - Out of heap space!\n");
 567                 return -1;
 568         }
 569         memcpy(new, &gThreadZero, sizeof(tThread));
 570         // Set Thread ID
 571         new->TID = giNextTID++;
 572         // Create a new worker stack (in PID0's address space)
 573         // The stack is relocated by this code
 574         new->KernelStack = MM_NewWorkerStack();
 575
 576         // Get ESP and EBP based in the new stack
 577         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 578         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 579         esp = new->KernelStack - (cur->KernelStack - esp);
 580         ebp = new->KernelStack - (cur->KernelStack - ebp);
 581
 582         // Save core machine state
 583         new->SavedState.ESP = esp;
 584         new->SavedState.EBP = ebp;
 585         eip = GetEIP();
 586         if(eip == SWITCH_MAGIC) {
 587                 outb(0x20, 0x20);       // ACK Timer and return as child
 588                 return 0;
 589         }
 590
 591         // Set EIP as parent
 592         new->SavedState.EIP = eip;
 593         // Mark as active
 594         new->Status = THREAD_STAT_ACTIVE;
 595         Threads_AddActive( new );
 596
 597         return new->TID;
 598 }
 599
 600 /**
 601  * \fn Uint Proc_MakeUserStack(void)
 602  * \brief Creates a new user stack
 603  */
 604 Uint Proc_MakeUserStack(void)
 605 {
 606          int    i;
 607         Uint    base = USER_STACK_TOP - USER_STACK_SZ;
 608
 609         // Check Prospective Space
 610         for( i = USER_STACK_SZ >> 12; i--; )
 611                 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
 612                         break;
 613
 614         if(i != -1)     return 0;
 615
 616         // Allocate Stack - Allocate incrementally to clean up MM_Dump output
 617         for( i = 0; i < USER_STACK_SZ/0x1000; i++ )
 618                 MM_Allocate( base + (i<<12) );
 619
 620         return base + USER_STACK_SZ;
 621 }
 622
 623 /**
 624  * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
 625  * \brief Starts a user task
 626  */
 627 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
 628 {
 629         Uint    *stack = (void*)Proc_MakeUserStack();
 630          int    i;
 631         Uint    delta;
 632         Uint16  ss, cs;
 633
 634         //Log("stack = %p", stack);
 635
 636         // Copy Arguments
 637         stack -= DataSize/sizeof(*stack);
 638         memcpy( stack, ArgV, DataSize );
 639
 640         //Log("stack = %p", stack);
 641
 642         if( DataSize )
 643         {
 644                 // Adjust Arguments and environment
 645                 delta = (Uint)stack - (Uint)ArgV;
 646                 ArgV = (char**)stack;
 647                 for( i = 0; ArgV[i]; i++ )
 648                         ArgV[i] += delta;
 649                 i ++;
 650
 651                 // Do we care about EnvP?
 652                 if( EnvP ) {
 653                         EnvP = &ArgV[i];
 654                         for( i = 0; EnvP[i]; i++ )
 655                                 EnvP[i] += delta;
 656                 }
 657         }
 658
 659         // User Mode Segments
 660         ss = 0x23;      cs = 0x1B;
 661
 662         // Arguments
 663         *--stack = (Uint)EnvP;
 664         *--stack = (Uint)ArgV;
 665         *--stack = (Uint)ArgC;
 666         while(*Bases)
 667                 *--stack = *Bases++;
 668         *--stack = 0;   // Return Address
 669
 670         Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
 671 }
 672
 673 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
 674 {
 675         Uint    *stack = (void*)Stack;
 676         *--stack = SS;          //Stack Segment
 677         *--stack = Stack;       //Stack Pointer
 678         *--stack = Flags;       //EFLAGS (Resvd (0x2) and IF (0x20))
 679         *--stack = CS;          //Code Segment
 680         *--stack = IP;  //EIP
 681         //PUSHAD
 682         *--stack = 0xAAAAAAAA;  // eax
 683         *--stack = 0xCCCCCCCC;  // ecx
 684         *--stack = 0xDDDDDDDD;  // edx
 685         *--stack = 0xBBBBBBBB;  // ebx
 686         *--stack = 0xD1D1D1D1;  // edi
 687         *--stack = 0x54545454;  // esp - NOT POPED
 688         *--stack = 0x51515151;  // esi
 689         *--stack = 0xB4B4B4B4;  // ebp
 690         //Individual PUSHs
 691         *--stack = SS;  // ds
 692         *--stack = SS;  // es
 693         *--stack = SS;  // fs
 694         *--stack = SS;  // gs
 695
 696         __asm__ __volatile__ (
 697         "mov %%eax,%%esp;\n\t"  // Set stack pointer
 698         "pop %%gs;\n\t"
 699         "pop %%fs;\n\t"
 700         "pop %%es;\n\t"
 701         "pop %%ds;\n\t"
 702         "popa;\n\t"
 703         "iret;\n\t" : : "a" (stack));
 704         for(;;);
 705 }
 706
 707 /**
 708  * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
 709  * \brief Demotes a process to a lower permission level
 710  * \param Err   Pointer to user's errno
 711  * \param Dest  New Permission Level
 712  * \param Regs  Pointer to user's register structure
 713  */
 714 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
 715 {
 716          int    cpl = Regs->cs & 3;
 717         // Sanity Check
 718         if(Dest > 3 || Dest < 0) {
 719                 *Err = -EINVAL;
 720                 return -1;
 721         }
 722
 723         // Permission Check
 724         if(cpl > Dest) {
 725                 *Err = -EACCES;
 726                 return -1;
 727         }
 728
 729         // Change the Segment Registers
 730         Regs->cs = (((Dest+1)<<4) | Dest) - 8;
 731         Regs->ss = ((Dest+1)<<4) | Dest;
 732         // Check if the GP Segs are GDT, then change them
 733         if(!(Regs->ds & 4))     Regs->ds = ((Dest+1)<<4) | Dest;
 734         if(!(Regs->es & 4))     Regs->es = ((Dest+1)<<4) | Dest;
 735         if(!(Regs->fs & 4))     Regs->fs = ((Dest+1)<<4) | Dest;
 736         if(!(Regs->gs & 4))     Regs->gs = ((Dest+1)<<4) | Dest;
 737
 738         return 0;
 739 }
 740
 741 /**
 742  * \brief Calls a signal handler in user mode
 743  * \note Used for signals
 744  */
 745 void Proc_CallFaultHandler(tThread *Thread)
 746 {
 747         // Rewinds the stack and calls the user function
 748         // Never returns
 749         __asm__ __volatile__ ("mov %0, %%ebp;\n\tcall Proc_ReturnToUser" :: "r"(Thread->FaultHandler));
 750         for(;;);
 751 }
 752
 753 /**
 754  * \fn void Proc_Scheduler(int CPU)
 755  * \brief Swap current thread and clears dead threads
 756  */
 757 void Proc_Scheduler(int CPU)
 758 {
 759         Uint    esp, ebp, eip;
 760         tThread *thread;
 761
 762         // If the spinlock is set, let it complete
 763         if(IS_LOCKED(&glThreadListLock))        return;
 764
 765         // Clear Delete Queue
 766         while(gDeleteThreads)
 767         {
 768                 thread = gDeleteThreads->Next;
 769                 if(gDeleteThreads->IsLocked) {  // Only free if structure is unused
 770                         gDeleteThreads->Status = THREAD_STAT_NULL;
 771                         free( gDeleteThreads );
 772                 }
 773                 gDeleteThreads = thread;
 774         }
 775
 776         // Check if there is any tasks running
 777         if(giNumActiveThreads == 0) {
 778                 Log("No Active threads, sleeping");
 779                 __asm__ __volatile__ ("hlt");
 780                 return;
 781         }
 782
 783         // Get current thread
 784         #if USE_MP
 785         thread = gaCPUs[CPU].Current;
 786         #else
 787         thread = gCurrentThread;
 788         #endif
 789
 790         // Reduce remaining quantum and continue timeslice if non-zero
 791         if(thread->Remaining--) return;
 792         // Reset quantum for next call
 793         thread->Remaining = thread->Quantum;
 794
 795         // Get machine state
 796         __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
 797         __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
 798         eip = GetEIP();
 799         if(eip == SWITCH_MAGIC) return; // Check if a switch happened
 800
 801         // Save machine state
 802         thread->SavedState.ESP = esp;
 803         thread->SavedState.EBP = ebp;
 804         thread->SavedState.EIP = eip;
 805
 806         // Get next thread
 807         thread = Threads_GetNextToRun(CPU);
 808
 809         // Error Check
 810         if(thread == NULL) {
 811                 Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
 812                 return;
 813         }
 814
 815         #if DEBUG_TRACE_SWITCH
 816         Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
 817                 thread->TID,
 818                 thread->MemState.CR3,
 819                 thread->SavedState.EIP
 820                 );
 821         #endif
 822
 823         // Set current thread
 824         #if USE_MP
 825         gaCPUs[CPU].Current = thread;
 826         #else
 827         gCurrentThread = thread;
 828         #endif
 829
 830         //Log("CPU = %i", CPU);
 831
 832         // Update Kernel Stack pointer
 833         gTSSs[CPU].ESP0 = thread->KernelStack-4;
 834
 835         // Set address space
 836         #if USE_PAE
 837         # error "Todo: Implement PAE Address space switching"
 838         #else
 839                 __asm__ __volatile__ ("mov %0, %%cr3"::"a"(thread->MemState.CR3));
 840         #endif
 841
 842         #if 0
 843         if(thread->SavedState.ESP > 0xC0000000
 844         && thread->SavedState.ESP < thread->KernelStack-0x2000) {
 845                 Log_Warning("Proc", "Possible bad ESP %p (PID %i)", thread->SavedState.ESP);
 846         }
 847         #endif
 848
 849         // Switch threads
 850         __asm__ __volatile__ (
 851                 "mov %1, %%esp\n\t"     // Restore ESP
 852                 "mov %2, %%ebp\n\t"     // and EBP
 853                 "jmp *%3" : :   // And return to where we saved state (Proc_Clone or Proc_Scheduler)
 854                 "a"(SWITCH_MAGIC), "b"(thread->SavedState.ESP),
 855                 "d"(thread->SavedState.EBP), "c"(thread->SavedState.EIP)
 856                 );
 857         for(;;);        // Shouldn't reach here
 858 }
 859
 860 // === EXPORTS ===
 861 EXPORT(Proc_SpawnWorker);