Kernel/arch/x86/proc.c

   1 /*
   2  * AcessOS Microkernel Version
   3  * proc.c
   4  */
   5 #include <acess.h>
   6 #include <threads.h>
   7 #include <proc.h>
   8 #include <desctab.h>
   9 #include <mm_virt.h>
  10 #include <errno.h>
  11 #if USE_MP
  12 # include <mp.h>
  13 #endif
  14
  15 // === FLAGS ===
  16 #define DEBUG_TRACE_SWITCH      0
  17 #define DEBUG_DISABLE_DOUBLEFAULT       1
  18
  19 // === CONSTANTS ===
  20 #define SWITCH_MAGIC    0xFF5317C8      // FF SWITCH - There is no code in this area
  21 // Base is 1193182
  22 #define TIMER_BASE      1193182
  23 #define TIMER_DIVISOR   11932   //~100Hz
  24
  25 // === TYPES ===
  26 #if USE_MP
  27 typedef struct sCPU
  28 {
  29         Uint8   APICID;
  30         Uint8   State;  // 0: Unavaliable, 1: Idle, 2: Active
  31         Uint16  Resvd;
  32         tThread *Current;
  33         tThread *IdleThread;
  34 }       tCPU;
  35 #endif
  36
  37 // === IMPORTS ===
  38 extern tGDT     gGDT[];
  39 extern tIDT     gIDT[];
  40 extern void APWait(void);       // 16-bit AP pause code
  41 extern void APStartup(void);    // 16-bit AP startup code
  42 extern Uint     GetEIP(void);   // start.asm
  43 extern int      GetCPUNum(void);        // start.asm
  44 extern Uint32   gaInitPageDir[1024];    // start.asm
  45 extern char     Kernel_Stack_Top[];
  46 extern tShortSpinlock   glThreadListLock;
  47 extern int      giNumCPUs;
  48 extern int      giNextTID;
  49 extern tThread  gThreadZero;
  50 extern tThread  *Threads_CloneTCB(Uint *Err, Uint Flags);
  51 extern void     Isr8(void);     // Double Fault
  52 extern void     Proc_ReturnToUser(tVAddr Handler, Uint Argument, tVAddr KernelStack);
  53
  54 // === PROTOTYPES ===
  55 void    ArchThreads_Init(void);
  56 #if USE_MP
  57 void    MP_StartAP(int CPU);
  58 void    MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode);
  59 #endif
  60 void    Proc_Start(void);
  61 tThread *Proc_GetCurThread(void);
  62 void    Proc_ChangeStack(void);
  63  int    Proc_Clone(Uint *Err, Uint Flags);
  64 void    Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
  65 void    Proc_CallFaultHandler(tThread *Thread);
  66 void    Proc_Scheduler(int CPU);
  67
  68 // === GLOBALS ===
  69 // --- Multiprocessing ---
  70 #if USE_MP
  71 volatile int    giNumInitingCPUs = 0;
  72 tMPInfo *gMPFloatPtr = NULL;
  73 volatile Uint32 giMP_TimerCount;        // Start Count for Local APIC Timer
  74 tAPIC   *gpMP_LocalAPIC = NULL;
  75 Uint8   gaAPIC_to_CPU[256] = {0};
  76 tCPU    gaCPUs[MAX_CPUS];
  77 tTSS    gaTSSs[MAX_CPUS];       // TSS Array
  78  int    giProc_BootProcessorID = 0;
  79 #else
  80 tThread *gCurrentThread = NULL;
  81 tThread *gpIdleThread = NULL;
  82 #endif
  83 #if USE_PAE
  84 Uint32  *gPML4s[4] = NULL;
  85 #endif
  86 tTSS    *gTSSs = NULL;  // Pointer to TSS array
  87 tTSS    gTSS0 = {0};
  88 // --- Error Recovery ---
  89 char    gaDoubleFaultStack[1024] __attribute__ ((section(".padata")));
  90 tTSS    gDoubleFault_TSS = {
  91         .ESP0 = (Uint)&gaDoubleFaultStack[1024],
  92         .SS0 = 0x10,
  93         .CR3 = (Uint)gaInitPageDir - KERNEL_BASE,
  94         .EIP = (Uint)Isr8,
  95         .ESP = (Uint)&gaDoubleFaultStack[1024],
  96         .CS = 0x08,     .SS = 0x10,
  97         .DS = 0x10,     .ES = 0x10,
  98         .FS = 0x10,     .GS = 0x10,
  99 };
 100
 101 // === CODE ===
 102 /**
 103  * \fn void ArchThreads_Init(void)
 104  * \brief Starts the process scheduler
 105  */
 106 void ArchThreads_Init(void)
 107 {
 108         Uint    pos = 0;
 109
 110         #if USE_MP
 111         tMPTable        *mptable;
 112
 113         // Mark BSP as active
 114         gaCPUs[0].State = 2;
 115
 116         // -- Initialise Multiprocessing
 117         // Find MP Floating Table
 118         // - EBDA/Last 1Kib (640KiB)
 119         for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
 120                 if( *(Uint*)(pos) == MPPTR_IDENT ) {
 121                         Log("Possible %p", pos);
 122                         if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 123                         gMPFloatPtr = (void*)pos;
 124                         break;
 125                 }
 126         }
 127         // - Last KiB (512KiB base mem)
 128         if(!gMPFloatPtr) {
 129                 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
 130                         if( *(Uint*)(pos) == MPPTR_IDENT ) {
 131                                 Log("Possible %p", pos);
 132                                 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 133                                 gMPFloatPtr = (void*)pos;
 134                                 break;
 135                         }
 136                 }
 137         }
 138         // - BIOS ROM
 139         if(!gMPFloatPtr) {
 140                 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
 141                         if( *(Uint*)(pos) == MPPTR_IDENT ) {
 142                                 Log("Possible %p", pos);
 143                                 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 144                                 gMPFloatPtr = (void*)pos;
 145                                 break;
 146                         }
 147                 }
 148         }
 149
 150         // If the MP Table Exists, parse it
 151         if(gMPFloatPtr)
 152         {
 153                  int    i;
 154                 tMPTable_Ent    *ents;
 155                 Log("gMPFloatPtr = %p", gMPFloatPtr);
 156                 Log("*gMPFloatPtr = {");
 157                 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
 158                 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
 159                 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
 160                 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
 161                 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
 162                 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
 163                         gMPFloatPtr->Features[0],       gMPFloatPtr->Features[1],
 164                         gMPFloatPtr->Features[2],       gMPFloatPtr->Features[3],
 165                         gMPFloatPtr->Features[4]
 166                         );
 167                 Log("}");
 168
 169                 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
 170                 Log("mptable = %p", mptable);
 171                 Log("*mptable = {");
 172                 Log("\t.Sig = 0x%08x", mptable->Sig);
 173                 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
 174                 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
 175                 Log("\t.Checksum = 0x%02x", mptable->Checksum);
 176                 Log("\t.OEMID = '%8c'", mptable->OemID);
 177                 Log("\t.ProductID = '%8c'", mptable->ProductID);
 178                 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
 179                 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
 180                 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
 181                 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
 182                 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
 183                 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
 184                 Log("}");
 185
 186                 gpMP_LocalAPIC = (void*)MM_MapHWPages(mptable->LocalAPICMemMap, 1);
 187
 188                 ents = mptable->Entries;
 189                 giNumCPUs = 0;
 190
 191                 for( i = 0; i < mptable->EntryCount; i ++ )
 192                 {
 193                          int    entSize = 0;
 194                         switch( ents->Type )
 195                         {
 196                         case 0: // Processor
 197                                 entSize = 20;
 198                                 Log("%i: Processor", i);
 199                                 Log("\t.APICID = %i", ents->Proc.APICID);
 200                                 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
 201                                 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
 202                                 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
 203                                 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
 204
 205
 206                                 if( !(ents->Proc.CPUFlags & 1) ) {
 207                                         Log("DISABLED");
 208                                         break;
 209                                 }
 210
 211                                 // Check if there is too many processors
 212                                 if(giNumCPUs >= MAX_CPUS) {
 213                                         giNumCPUs ++;   // If `giNumCPUs` > MAX_CPUS later, it will be clipped
 214                                         break;
 215                                 }
 216
 217                                 // Initialise CPU Info
 218                                 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
 219                                 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
 220                                 gaCPUs[giNumCPUs].State = 0;
 221                                 giNumCPUs ++;
 222
 223                                 // Set BSP Variable
 224                                 if( ents->Proc.CPUFlags & 2 ) {
 225                                         giProc_BootProcessorID = giNumCPUs-1;
 226                                 }
 227
 228                                 break;
 229
 230                         #if DUMP_MP_TABLES
 231                         case 1: // Bus
 232                                 entSize = 8;
 233                                 Log("%i: Bus", i);
 234                                 Log("\t.ID = %i", ents->Bus.ID);
 235                                 Log("\t.TypeString = '%6C'", ents->Bus.TypeString);
 236                                 break;
 237                         case 2: // I/O APIC
 238                                 entSize = 8;
 239                                 Log("%i: I/O APIC", i);
 240                                 Log("\t.ID = %i", ents->IOAPIC.ID);
 241                                 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
 242                                 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
 243                                 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
 244                                 break;
 245                         case 3: // I/O Interrupt Assignment
 246                                 entSize = 8;
 247                                 Log("%i: I/O Interrupt Assignment", i);
 248                                 Log("\t.IntType = %i", ents->IOInt.IntType);
 249                                 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
 250                                 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
 251                                 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
 252                                 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
 253                                 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
 254                                 break;
 255                         case 4: // Local Interrupt Assignment
 256                                 entSize = 8;
 257                                 Log("%i: Local Interrupt Assignment", i);
 258                                 Log("\t.IntType = %i", ents->LocalInt.IntType);
 259                                 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
 260                                 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
 261                                 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
 262                                 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
 263                                 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
 264                                 break;
 265                         default:
 266                                 Log("%i: Unknown (%i)", i, ents->Type);
 267                                 break;
 268                         #endif
 269                         }
 270                         ents = (void*)( (Uint)ents + entSize );
 271                 }
 272
 273                 if( giNumCPUs > MAX_CPUS ) {
 274                         Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
 275                         giNumCPUs = MAX_CPUS;
 276                 }
 277                 gTSSs = gaTSSs;
 278         }
 279         else {
 280                 Log("No MP Table was found, assuming uniprocessor\n");
 281                 giNumCPUs = 1;
 282                 gTSSs = &gTSS0;
 283         }
 284         #else
 285         giNumCPUs = 1;
 286         gTSSs = &gTSS0;
 287         MM_FinishVirtualInit();
 288         #endif
 289
 290         #if !DEBUG_DISABLE_DOUBLEFAULT
 291         // Initialise Double Fault TSS
 292         gGDT[5].BaseLow = (Uint)&gDoubleFault_TSS & 0xFFFF;
 293         gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
 294         gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
 295
 296         // Set double fault IDT to use the new TSS
 297         gIDT[8].OffsetLo = 0;
 298         gIDT[8].CS = 5<<3;
 299         gIDT[8].Flags = 0x8500;
 300         gIDT[8].OffsetHi = 0;
 301         #endif
 302
 303         // Set timer frequency
 304         outb(0x43, 0x34);       // Set Channel 0, Low/High, Rate Generator
 305         outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
 306         outb(0x40, (TIMER_DIVISOR>>8)&0xFF);    // High Byte
 307
 308         Log("Timer Frequency %i.%03i Hz",
 309                 TIMER_BASE/TIMER_DIVISOR,
 310                 ((Uint64)TIMER_BASE*1000/TIMER_DIVISOR)%1000
 311                 );
 312
 313         #if USE_MP
 314         // Get the count setting for APIC timer
 315         Log("Determining APIC Count");
 316         __asm__ __volatile__ ("sti");
 317         while( giMP_TimerCount == 0 )   __asm__ __volatile__ ("hlt");
 318         __asm__ __volatile__ ("cli");
 319         Log("APIC Count %i", giMP_TimerCount);
 320         {
 321                 Uint64  freq = giMP_TimerCount;
 322                 freq /= TIMER_DIVISOR;
 323                 freq *= TIMER_BASE;
 324                 if( (freq /= 1000) < 2*1000)
 325                         Log("Bus Frequency %i KHz", freq);
 326                 else if( (freq /= 1000) < 2*1000)
 327                         Log("Bus Frequency %i MHz", freq);
 328                 else if( (freq /= 1000) < 2*1000)
 329                         Log("Bus Frequency %i GHz", freq);
 330                 else
 331                         Log("Bus Frequency %i THz", freq);
 332         }
 333
 334         // Initialise Normal TSS(s)
 335         for(pos=0;pos<giNumCPUs;pos++)
 336         {
 337         #else
 338         pos = 0;
 339         #endif
 340                 gTSSs[pos].SS0 = 0x10;
 341                 gTSSs[pos].ESP0 = 0;    // Set properly by scheduler
 342                 gGDT[6+pos].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
 343                 gGDT[6+pos].BaseMid = ((Uint)(&gTSSs[pos]) >> 16) & 0xFFFF;
 344                 gGDT[6+pos].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
 345         #if USE_MP
 346         }
 347         #endif
 348
 349         // Load the BSP's TSS
 350         __asm__ __volatile__ ("ltr %%ax"::"a"(0x30));
 351         // Set Current Thread and CPU Number in DR0 and DR1
 352         __asm__ __volatile__ ("mov %0, %%db0"::"r"(&gThreadZero));
 353         __asm__ __volatile__ ("mov %0, %%db1"::"r"(0));
 354
 355         #if USE_MP
 356         gaCPUs[0].Current = &gThreadZero;
 357         #else
 358         gCurrentThread = &gThreadZero;
 359         #endif
 360         gThreadZero.CurCPU = 0;
 361
 362         #if USE_PAE
 363         gThreadZero.MemState.PDP[0] = 0;
 364         gThreadZero.MemState.PDP[1] = 0;
 365         gThreadZero.MemState.PDP[2] = 0;
 366         #else
 367         gThreadZero.MemState.CR3 = (Uint)gaInitPageDir - KERNEL_BASE;
 368         #endif
 369
 370         // Create Per-Process Data Block
 371         if( !MM_Allocate(MM_PPD_CFG) )
 372         {
 373                 Panic("OOM - No space for initiali Per-Process Config");
 374         }
 375
 376         // Change Stacks
 377         Proc_ChangeStack();
 378 }
 379
 380 #if USE_MP
 381 void MP_StartAP(int CPU)
 382 {
 383         Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
 384
 385         // Set location of AP startup code and mark for a warm restart
 386         *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APWait - (KERNEL_BASE|0xFFFF0);
 387         *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
 388         outb(0x70, 0x0F);       outb(0x71, 0x0A);       // Set warm reset flag
 389         MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);   // Init IPI
 390
 391         // Delay
 392         inb(0x80); inb(0x80); inb(0x80); inb(0x80);
 393
 394         // TODO: Use a better address, preferably registered with the MM
 395         // - MM_AllocDMA mabye?
 396         // Create a far jump
 397         *(Uint8*)(KERNEL_BASE|0x11000) = 0xEA;  // Far JMP
 398         *(Uint16*)(KERNEL_BASE|0x11001) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);     // IP
 399         *(Uint16*)(KERNEL_BASE|0x11003) = 0xFFFF;       // CS
 400         // Send a Startup-IPI to make the CPU execute at 0x11000 (which we
 401         // just filled)
 402         MP_SendIPI(gaCPUs[CPU].APICID, 0x11, 6);        // StartupIPI
 403
 404         giNumInitingCPUs ++;
 405 }
 406
 407 /**
 408  * \brief Send an Inter-Processor Interrupt
 409  * \param APICID        Processor's Local APIC ID
 410  * \param Vector        Argument of some kind
 411  * \param DeliveryMode  Type of signal?
 412  */
 413 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
 414 {
 415         Uint32  val;
 416
 417         // Hi
 418         val = (Uint)APICID << 24;
 419         Log("*%p = 0x%08x", &gpMP_LocalAPIC->ICR[1], val);
 420         gpMP_LocalAPIC->ICR[1].Val = val;
 421         // Low (and send)
 422         val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
 423         Log("*%p = 0x%08x", &gpMP_LocalAPIC->ICR[0], val);
 424         gpMP_LocalAPIC->ICR[0].Val = val;
 425 }
 426 #endif
 427
 428 /**
 429  * \fn void Proc_Start(void)
 430  * \brief Start process scheduler
 431  */
 432 void Proc_Start(void)
 433 {
 434         #if USE_MP
 435          int    i;
 436         #endif
 437
 438         #if USE_MP
 439         // Start APs
 440         for( i = 0; i < giNumCPUs; i ++ )
 441         {
 442                  int    tid;
 443                 if(i)   gaCPUs[i].Current = NULL;
 444
 445                 // Create Idle Task
 446                 if( (tid = Proc_Clone(0, 0)) == 0)
 447                 {
 448                         for(;;) HALT(); // Just yeilds
 449                 }
 450                 gaCPUs[i].IdleThread = Threads_GetThread(tid);
 451                 gaCPUs[i].IdleThread->ThreadName = "Idle Thread";
 452                 Threads_SetPriority( gaCPUs[i].IdleThread, -1 );        // Never called randomly
 453                 gaCPUs[i].IdleThread->Quantum = 1;      // 1 slice quantum
 454
 455
 456                 // Start the AP
 457                 if( i != giProc_BootProcessorID ) {
 458                         MP_StartAP( i );
 459                 }
 460         }
 461
 462         // BSP still should run the current task
 463         gaCPUs[0].Current = &gThreadZero;
 464
 465         // Start interrupts and wait for APs to come up
 466         Log("Waiting for APs to come up\n");
 467         __asm__ __volatile__ ("sti");
 468         while( giNumInitingCPUs )       __asm__ __volatile__ ("hlt");
 469         #else
 470         // Create Idle Task
 471         if(Proc_Clone(0, 0) == 0)
 472         {
 473                 gpIdleThread = Proc_GetCurThread();
 474                 gpIdleThread->ThreadName = "Idle Thread";
 475                 Threads_SetPriority( gpIdleThread, -1 );        // Never called randomly
 476                 gpIdleThread->Quantum = 1;      // 1 slice quantum
 477                 for(;;) HALT(); // Just yeilds
 478         }
 479
 480         // Set current task
 481         gCurrentThread = &gThreadZero;
 482
 483         // Start Interrupts (and hence scheduler)
 484         __asm__ __volatile__("sti");
 485         #endif
 486         MM_FinishVirtualInit();
 487 }
 488
 489 /**
 490  * \fn tThread *Proc_GetCurThread(void)
 491  * \brief Gets the current thread
 492  */
 493 tThread *Proc_GetCurThread(void)
 494 {
 495         #if USE_MP
 496         return gaCPUs[ GetCPUNum() ].Current;
 497         #else
 498         return gCurrentThread;
 499         #endif
 500 }
 501
 502 /**
 503  * \fn void Proc_ChangeStack(void)
 504  * \brief Swaps the current stack for a new one (in the proper stack reigon)
 505  */
 506 void Proc_ChangeStack(void)
 507 {
 508         Uint    esp, ebp;
 509         Uint    tmpEbp, oldEsp;
 510         Uint    curBase, newBase;
 511
 512         __asm__ __volatile__ ("mov %%esp, %0":"=r"(esp));
 513         __asm__ __volatile__ ("mov %%ebp, %0":"=r"(ebp));
 514
 515         oldEsp = esp;
 516
 517         // Create new KStack
 518         newBase = MM_NewKStack();
 519         // Check for errors
 520         if(newBase == 0) {
 521                 Panic("What the?? Unable to allocate space for initial kernel stack");
 522                 return;
 523         }
 524
 525         curBase = (Uint)&Kernel_Stack_Top;
 526
 527         LOG("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
 528
 529         // Get ESP as a used size
 530         esp = curBase - esp;
 531         LOG("memcpy( %p, %p, 0x%x )", (void*)(newBase - esp), (void*)(curBase - esp), esp );
 532         // Copy used stack
 533         memcpy( (void*)(newBase - esp), (void*)(curBase - esp), esp );
 534         // Get ESP as an offset in the new stack
 535         esp = newBase - esp;
 536         // Adjust EBP
 537         ebp = newBase - (curBase - ebp);
 538
 539         // Repair EBPs & Stack Addresses
 540         // Catches arguments also, but may trash stack-address-like values
 541         for(tmpEbp = esp; tmpEbp < newBase; tmpEbp += 4)
 542         {
 543                 if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < curBase)
 544                         *(Uint*)tmpEbp += newBase - curBase;
 545         }
 546
 547         Proc_GetCurThread()->KernelStack = newBase;
 548
 549         __asm__ __volatile__ ("mov %0, %%esp"::"r"(esp));
 550         __asm__ __volatile__ ("mov %0, %%ebp"::"r"(ebp));
 551 }
 552
 553 /**
 554  * \fn int Proc_Clone(Uint *Err, Uint Flags)
 555  * \brief Clone the current process
 556  */
 557 int Proc_Clone(Uint *Err, Uint Flags)
 558 {
 559         tThread *newThread;
 560         tThread *cur = Proc_GetCurThread();
 561         Uint    eip, esp, ebp;
 562
 563         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 564         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 565
 566         newThread = Threads_CloneTCB(Err, Flags);
 567         if(!newThread)  return -1;
 568
 569         // Initialise Memory Space (New Addr space or kernel stack)
 570         if(Flags & CLONE_VM) {
 571                 newThread->MemState.CR3 = MM_Clone();
 572                 // Check for errors
 573                 if(newThread->MemState.CR3 == 0) {
 574                         Threads_Kill(newThread, -2);
 575                         return -1;
 576                 }
 577                 newThread->KernelStack = cur->KernelStack;
 578         } else {
 579                 Uint    tmpEbp, oldEsp = esp;
 580
 581                 // Set CR3
 582                 #if USE_PAE
 583                 # warning "PAE Unimplemented"
 584                 #else
 585                 newThread->MemState.CR3 = cur->MemState.CR3;
 586                 #endif
 587
 588                 // Create new KStack
 589                 newThread->KernelStack = MM_NewKStack();
 590                 // Check for errors
 591                 if(newThread->KernelStack == 0) {
 592                         Threads_Kill(newThread, -2);
 593                         return -1;
 594                 }
 595
 596                 // Get ESP as a used size
 597                 esp = cur->KernelStack - esp;
 598                 // Copy used stack
 599                 memcpy( (void*)(newThread->KernelStack - esp), (void*)(cur->KernelStack - esp), esp );
 600                 // Get ESP as an offset in the new stack
 601                 esp = newThread->KernelStack - esp;
 602                 // Adjust EBP
 603                 ebp = newThread->KernelStack - (cur->KernelStack - ebp);
 604
 605                 // Repair EBPs & Stack Addresses
 606                 // Catches arguments also, but may trash stack-address-like values
 607                 for(tmpEbp = esp; tmpEbp < newThread->KernelStack; tmpEbp += 4)
 608                 {
 609                         if(oldEsp < *(Uint*)tmpEbp && *(Uint*)tmpEbp < cur->KernelStack)
 610                                 *(Uint*)tmpEbp += newThread->KernelStack - cur->KernelStack;
 611                 }
 612         }
 613
 614         // Save core machine state
 615         newThread->SavedState.ESP = esp;
 616         newThread->SavedState.EBP = ebp;
 617         eip = GetEIP();
 618         if(eip == SWITCH_MAGIC) {
 619                 __asm__ __volatile__ ("mov %0, %%db0" : : "r" (newThread) );
 620                 #if USE_MP
 621                 // ACK the interrupt
 622                 if( GetCPUNum() )
 623                         gpMP_LocalAPIC->EOI.Val = 0;
 624                 else
 625                 #endif
 626                         outb(0x20, 0x20);       // ACK Timer and return as child
 627                 __asm__ __volatile__ ("sti");   // Restart interrupts
 628                 return 0;
 629         }
 630
 631         // Set EIP as parent
 632         newThread->SavedState.EIP = eip;
 633
 634         // Lock list and add to active
 635         Threads_AddActive(newThread);
 636
 637         return newThread->TID;
 638 }
 639
 640 /**
 641  * \fn int Proc_SpawnWorker(void)
 642  * \brief Spawns a new worker thread
 643  */
 644 int Proc_SpawnWorker(void)
 645 {
 646         tThread *new, *cur;
 647         Uint    eip, esp, ebp;
 648
 649         cur = Proc_GetCurThread();
 650
 651         // Create new thread
 652         new = malloc( sizeof(tThread) );
 653         if(!new) {
 654                 Warning("Proc_SpawnWorker - Out of heap space!\n");
 655                 return -1;
 656         }
 657         memcpy(new, &gThreadZero, sizeof(tThread));
 658         // Set Thread ID
 659         new->TID = giNextTID++;
 660         // Create a new worker stack (in PID0's address space)
 661         // - The stack is relocated by this function
 662         new->KernelStack = MM_NewWorkerStack();
 663
 664         // Get ESP and EBP based in the new stack
 665         __asm__ __volatile__ ("mov %%esp, %0": "=r"(esp));
 666         __asm__ __volatile__ ("mov %%ebp, %0": "=r"(ebp));
 667         esp = new->KernelStack - (cur->KernelStack - esp);
 668         ebp = new->KernelStack - (cur->KernelStack - ebp);
 669
 670         // Save core machine state
 671         new->SavedState.ESP = esp;
 672         new->SavedState.EBP = ebp;
 673         eip = GetEIP();
 674         if(eip == SWITCH_MAGIC) {
 675                 __asm__ __volatile__ ("mov %0, %%db0" : : "r"(new));
 676                 #if USE_MP
 677                 // ACK the interrupt
 678                 if(GetCPUNum())
 679                         gpMP_LocalAPIC->EOI.Val = 0;
 680                 else
 681                 #endif
 682                         outb(0x20, 0x20);       // ACK Timer and return as child
 683                 __asm__ __volatile__ ("sti");   // Restart interrupts
 684                 return 0;
 685         }
 686
 687         // Set EIP as parent
 688         new->SavedState.EIP = eip;
 689         // Mark as active
 690         Threads_AddActive( new );
 691
 692         return new->TID;
 693 }
 694
 695 /**
 696  * \fn Uint Proc_MakeUserStack(void)
 697  * \brief Creates a new user stack
 698  */
 699 Uint Proc_MakeUserStack(void)
 700 {
 701          int    i;
 702         Uint    base = USER_STACK_TOP - USER_STACK_SZ;
 703
 704         // Check Prospective Space
 705         for( i = USER_STACK_SZ >> 12; i--; )
 706                 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
 707                         break;
 708
 709         if(i != -1)     return 0;
 710
 711         // Allocate Stack - Allocate incrementally to clean up MM_Dump output
 712         for( i = 0; i < USER_STACK_SZ/0x1000; i++ )
 713         {
 714                 if( !MM_Allocate( base + (i<<12) ) )
 715                 {
 716                         Warning("OOM: Proc_MakeUserStack");
 717                         return 0;
 718                 }
 719         }
 720
 721         return base + USER_STACK_SZ;
 722 }
 723
 724 /**
 725  * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
 726  * \brief Starts a user task
 727  */
 728 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
 729 {
 730         Uint    *stack = (void*)Proc_MakeUserStack();
 731          int    i;
 732         Uint    delta;
 733         Uint16  ss, cs;
 734
 735         //Log("stack = %p", stack);
 736
 737         // Copy Arguments
 738         stack -= DataSize/sizeof(*stack);
 739         memcpy( stack, ArgV, DataSize );
 740
 741         //Log("stack = %p", stack);
 742
 743         if( DataSize )
 744         {
 745                 // Adjust Arguments and environment
 746                 delta = (Uint)stack - (Uint)ArgV;
 747                 ArgV = (char**)stack;
 748                 for( i = 0; ArgV[i]; i++ )
 749                         ArgV[i] += delta;
 750                 i ++;
 751
 752                 // Do we care about EnvP?
 753                 if( EnvP ) {
 754                         EnvP = &ArgV[i];
 755                         for( i = 0; EnvP[i]; i++ )
 756                                 EnvP[i] += delta;
 757                 }
 758         }
 759
 760         // User Mode Segments
 761         ss = 0x23;      cs = 0x1B;
 762
 763         // Arguments
 764         *--stack = (Uint)EnvP;
 765         *--stack = (Uint)ArgV;
 766         *--stack = (Uint)ArgC;
 767         while(*Bases)
 768                 *--stack = *Bases++;
 769         *--stack = 0;   // Return Address
 770
 771         Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
 772 }
 773
 774 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
 775 {
 776         Uint    *stack = (void*)Stack;
 777         *--stack = SS;          //Stack Segment
 778         *--stack = Stack;       //Stack Pointer
 779         *--stack = Flags;       //EFLAGS (Resvd (0x2) and IF (0x20))
 780         *--stack = CS;          //Code Segment
 781         *--stack = IP;  //EIP
 782         //PUSHAD
 783         *--stack = 0xAAAAAAAA;  // eax
 784         *--stack = 0xCCCCCCCC;  // ecx
 785         *--stack = 0xDDDDDDDD;  // edx
 786         *--stack = 0xBBBBBBBB;  // ebx
 787         *--stack = 0xD1D1D1D1;  // edi
 788         *--stack = 0x54545454;  // esp - NOT POPED
 789         *--stack = 0x51515151;  // esi
 790         *--stack = 0xB4B4B4B4;  // ebp
 791         //Individual PUSHs
 792         *--stack = SS;  // ds
 793         *--stack = SS;  // es
 794         *--stack = SS;  // fs
 795         *--stack = SS;  // gs
 796
 797         __asm__ __volatile__ (
 798         "mov %%eax,%%esp;\n\t"  // Set stack pointer
 799         "pop %%gs;\n\t"
 800         "pop %%fs;\n\t"
 801         "pop %%es;\n\t"
 802         "pop %%ds;\n\t"
 803         "popa;\n\t"
 804         "iret;\n\t" : : "a" (stack));
 805         for(;;);
 806 }
 807
 808 /**
 809  * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
 810  * \brief Demotes a process to a lower permission level
 811  * \param Err   Pointer to user's errno
 812  * \param Dest  New Permission Level
 813  * \param Regs  Pointer to user's register structure
 814  */
 815 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
 816 {
 817          int    cpl = Regs->cs & 3;
 818         // Sanity Check
 819         if(Dest > 3 || Dest < 0) {
 820                 *Err = -EINVAL;
 821                 return -1;
 822         }
 823
 824         // Permission Check
 825         if(cpl > Dest) {
 826                 *Err = -EACCES;
 827                 return -1;
 828         }
 829
 830         // Change the Segment Registers
 831         Regs->cs = (((Dest+1)<<4) | Dest) - 8;
 832         Regs->ss = ((Dest+1)<<4) | Dest;
 833         // Check if the GP Segs are GDT, then change them
 834         if(!(Regs->ds & 4))     Regs->ds = ((Dest+1)<<4) | Dest;
 835         if(!(Regs->es & 4))     Regs->es = ((Dest+1)<<4) | Dest;
 836         if(!(Regs->fs & 4))     Regs->fs = ((Dest+1)<<4) | Dest;
 837         if(!(Regs->gs & 4))     Regs->gs = ((Dest+1)<<4) | Dest;
 838
 839         return 0;
 840 }
 841
 842 /**
 843  * \brief Calls a signal handler in user mode
 844  * \note Used for signals
 845  */
 846 void Proc_CallFaultHandler(tThread *Thread)
 847 {
 848         // Rewinds the stack and calls the user function
 849         // Never returns
 850         Proc_ReturnToUser( Thread->FaultHandler, Thread->CurFaultNum, Thread->KernelStack );
 851         for(;;);
 852 }
 853
 854 /**
 855  * \fn void Proc_Scheduler(int CPU)
 856  * \brief Swap current thread and clears dead threads
 857  */
 858 void Proc_Scheduler(int CPU)
 859 {
 860         Uint    esp, ebp, eip;
 861         tThread *thread;
 862
 863         // If the spinlock is set, let it complete
 864         if(IS_LOCKED(&glThreadListLock))        return;
 865
 866         // Get current thread
 867         #if USE_MP
 868         thread = gaCPUs[CPU].Current;
 869         #else
 870         thread = gCurrentThread;
 871         #endif
 872
 873         if( thread )
 874         {
 875                 // Reduce remaining quantum and continue timeslice if non-zero
 876                 if( thread->Remaining-- )
 877                         return;
 878                 // Reset quantum for next call
 879                 thread->Remaining = thread->Quantum;
 880
 881                 // Get machine state
 882                 __asm__ __volatile__ ( "mov %%esp, %0" : "=r" (esp) );
 883                 __asm__ __volatile__ ( "mov %%ebp, %0" : "=r" (ebp) );
 884                 eip = GetEIP();
 885                 if(eip == SWITCH_MAGIC) return; // Check if a switch happened
 886
 887                 // Save machine state
 888                 thread->SavedState.ESP = esp;
 889                 thread->SavedState.EBP = ebp;
 890                 thread->SavedState.EIP = eip;
 891         }
 892
 893         // Get next thread to run
 894         thread = Threads_GetNextToRun(CPU, thread);
 895
 896         // No avaliable tasks, just go into low power mode (idle thread)
 897         if(thread == NULL) {
 898                 #if USE_MP
 899                 thread = gaCPUs[CPU].IdleThread;
 900                 Log("CPU %i Running Idle Thread", CPU);
 901                 #else
 902                 thread = gpIdleThread;
 903                 #endif
 904         }
 905
 906         // Set current thread
 907         #if USE_MP
 908         gaCPUs[CPU].Current = thread;
 909         #else
 910         gCurrentThread = thread;
 911         #endif
 912
 913         #if DEBUG_TRACE_SWITCH
 914         Log("Switching to task %i, CR3 = 0x%x, EIP = %p",
 915                 thread->TID,
 916                 thread->MemState.CR3,
 917                 thread->SavedState.EIP
 918                 );
 919         #endif
 920
 921         #if USE_MP      // MP Debug
 922         Log("CPU = %i, Thread %p", CPU, thread);
 923         #endif
 924
 925         // Update Kernel Stack pointer
 926         gTSSs[CPU].ESP0 = thread->KernelStack-4;
 927
 928         // Set address space
 929         #if USE_PAE
 930         # error "Todo: Implement PAE Address space switching"
 931         #else
 932         __asm__ __volatile__ ("mov %0, %%cr3" : : "a" (thread->MemState.CR3));
 933         #endif
 934
 935         #if 0
 936         if(thread->SavedState.ESP > 0xC0000000
 937         && thread->SavedState.ESP < thread->KernelStack-0x2000) {
 938                 Log_Warning("Proc", "Possible bad ESP %p (PID %i)", thread->SavedState.ESP);
 939         }
 940         #endif
 941
 942         // Switch threads
 943         __asm__ __volatile__ (
 944                 "mov %1, %%esp\n\t"     // Restore ESP
 945                 "mov %2, %%ebp\n\t"     // and EBP
 946                 "jmp *%3" : :   // And return to where we saved state (Proc_Clone or Proc_Scheduler)
 947                 "a"(SWITCH_MAGIC), "b"(thread->SavedState.ESP),
 948                 "d"(thread->SavedState.EBP), "c"(thread->SavedState.EIP)
 949                 );
 950         for(;;);        // Shouldn't reach here
 951 }
 952
 953 // === EXPORTS ===
 954 EXPORT(Proc_SpawnWorker);