Kernel/arch/x86_64/proc.c

   1 /*
   2  * Acess2 x86_64 port
   3  * proc.c
   4  */
   5 #include <acess.h>
   6 #include <proc.h>
   7 #include <threads.h>
   8 #include <threads_int.h>
   9 #include <desctab.h>
  10 #include <mm_virt.h>
  11 #include <errno.h>
  12 #if USE_MP
  13 # include <mp.h>
  14 #endif
  15 #include <arch_config.h>
  16 #include <hal_proc.h>
  17
  18 // === FLAGS ===
  19 #define DEBUG_TRACE_SWITCH      0
  20 //#define BREAK_ON_SWITCH       1       // Break into bochs debugger on a task switch
  21
  22 // === CONSTANTS ===
  23 #define SWITCH_MAGIC    0x55ECAFFF##FFFACE55    // There is no code in this area
  24
  25 // === TYPES ===
  26 typedef struct sCPU
  27 {
  28         Uint8   APICID;
  29         Uint8   State;  // 0: Unavaliable, 1: Idle, 2: Active
  30         Uint16  Resvd;
  31         tThread *Current;
  32         tThread *IdleThread;
  33 }       tCPU;
  34
  35 // === IMPORTS ===
  36 extern tGDT     gGDT[];
  37 extern void     APStartup(void);        // 16-bit AP startup code
  38 extern Uint     GetRIP(void);   // start.asm
  39 extern Uint64   gInitialPML4[512];      // start.asm
  40 extern char     gInitialKernelStack[];
  41 extern tShortSpinlock   glThreadListLock;
  42 extern int      giNumCPUs;
  43 extern int      giNextTID;
  44 extern int      giTotalTickets;
  45 extern int      giNumActiveThreads;
  46 extern tThread  gThreadZero;
  47 extern void     Threads_Dump(void);
  48 extern void     Proc_ReturnToUser(void);
  49 extern void     Time_UpdateTimestamp(void);
  50
  51 // === PROTOTYPES ===
  52 //void  ArchThreads_Init(void);
  53 #if USE_MP
  54 void    MP_StartAP(int CPU);
  55 void    MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode);
  56 #endif
  57 //void  Proc_Start(void);
  58 //tThread       *Proc_GetCurThread(void);
  59 void    Proc_ChangeStack(void);
  60 // int  Proc_Clone(Uint *Err, Uint Flags);
  61 // int  Proc_SpawnWorker(void);
  62 Uint    Proc_MakeUserStack(void);
  63 //void  Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize);
  64 void    Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
  65  int    Proc_Demote(Uint *Err, int Dest, tRegs *Regs);
  66 //void  Proc_CallFaultHandler(tThread *Thread);
  67 //void  Proc_DumpThreadCPUState(tThread *Thread);
  68 void    Proc_Scheduler(int CPU);
  69
  70 // === GLOBALS ===
  71 // --- Multiprocessing ---
  72 #if USE_MP
  73 volatile int    giNumInitingCPUs = 0;
  74 tMPInfo *gMPFloatPtr = NULL;
  75 tAPIC   *gpMP_LocalAPIC = NULL;
  76 Uint8   gaAPIC_to_CPU[256] = {0};
  77 #endif
  78 tCPU    gaCPUs[MAX_CPUS];
  79 tTSS    *gTSSs = NULL;
  80 tTSS    gTSS0 = {0};
  81 // --- Error Recovery ---
  82 Uint32  gaDoubleFaultStack[1024];
  83
  84 // === CODE ===
  85 /**
  86  * \fn void ArchThreads_Init(void)
  87  * \brief Starts the process scheduler
  88  */
  89 void ArchThreads_Init(void)
  90 {
  91         Uint    pos = 0;
  92
  93         #if USE_MP
  94         tMPTable        *mptable;
  95
  96         // Mark BSP as active
  97         gaCPUs[0].State = 2;
  98
  99         // -- Initialise Multiprocessing
 100         // Find MP Floating Table
 101         // - EBDA/Last 1Kib (640KiB)
 102         for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
 103                 if( *(Uint*)(pos) == MPPTR_IDENT ) {
 104                         Log("Possible %p", pos);
 105                         if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 106                         gMPFloatPtr = (void*)pos;
 107                         break;
 108                 }
 109         }
 110         // - Last KiB (512KiB base mem)
 111         if(!gMPFloatPtr) {
 112                 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
 113                         if( *(Uint*)(pos) == MPPTR_IDENT ) {
 114                                 Log("Possible %p", pos);
 115                                 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 116                                 gMPFloatPtr = (void*)pos;
 117                                 break;
 118                         }
 119                 }
 120         }
 121         // - BIOS ROM
 122         if(!gMPFloatPtr) {
 123                 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
 124                         if( *(Uint*)(pos) == MPPTR_IDENT ) {
 125                                 Log("Possible %p", pos);
 126                                 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 127                                 gMPFloatPtr = (void*)pos;
 128                                 break;
 129                         }
 130                 }
 131         }
 132
 133         // If the MP Table Exists, parse it
 134         if(gMPFloatPtr)
 135         {
 136                  int    i;
 137                 tMPTable_Ent    *ents;
 138                 Log("gMPFloatPtr = %p", gMPFloatPtr);
 139                 Log("*gMPFloatPtr = {");
 140                 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
 141                 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
 142                 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
 143                 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
 144                 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
 145                 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
 146                         gMPFloatPtr->Features[0],       gMPFloatPtr->Features[1],
 147                         gMPFloatPtr->Features[2],       gMPFloatPtr->Features[3],
 148                         gMPFloatPtr->Features[4]
 149                         );
 150                 Log("}");
 151
 152                 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
 153                 Log("mptable = %p", mptable);
 154                 Log("*mptable = {");
 155                 Log("\t.Sig = 0x%08x", mptable->Sig);
 156                 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
 157                 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
 158                 Log("\t.Checksum = 0x%02x", mptable->Checksum);
 159                 Log("\t.OEMID = '%8c'", mptable->OemID);
 160                 Log("\t.ProductID = '%8c'", mptable->ProductID);
 161                 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
 162                 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
 163                 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
 164                 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
 165                 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
 166                 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
 167                 Log("}");
 168
 169                 gpMP_LocalAPIC = (void*)MM_MapHWPage(mptable->LocalAPICMemMap, 1);
 170
 171                 ents = mptable->Entries;
 172                 giNumCPUs = 0;
 173
 174                 for( i = 0; i < mptable->EntryCount; i ++ )
 175                 {
 176                          int    entSize = 0;
 177                         switch( ents->Type )
 178                         {
 179                         case 0: // Processor
 180                                 entSize = 20;
 181                                 Log("%i: Processor", i);
 182                                 Log("\t.APICID = %i", ents->Proc.APICID);
 183                                 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
 184                                 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
 185                                 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
 186                                 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
 187
 188
 189                                 if( !(ents->Proc.CPUFlags & 1) ) {
 190                                         Log("DISABLED");
 191                                         break;
 192                                 }
 193
 194                                 // Check if there is too many processors
 195                                 if(giNumCPUs >= MAX_CPUS) {
 196                                         giNumCPUs ++;   // If `giNumCPUs` > MAX_CPUS later, it will be clipped
 197                                         break;
 198                                 }
 199
 200                                 // Initialise CPU Info
 201                                 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
 202                                 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
 203                                 gaCPUs[giNumCPUs].State = 0;
 204                                 giNumCPUs ++;
 205
 206                                 // Send IPI
 207                                 if( !(ents->Proc.CPUFlags & 2) )
 208                                 {
 209                                         MP_StartAP( giNumCPUs-1 );
 210                                 }
 211
 212                                 break;
 213                         case 1: // Bus
 214                                 entSize = 8;
 215                                 Log("%i: Bus", i);
 216                                 Log("\t.ID = %i", ents->Bus.ID);
 217                                 Log("\t.TypeString = '%6c'", ents->Bus.TypeString);
 218                                 break;
 219                         case 2: // I/O APIC
 220                                 entSize = 8;
 221                                 Log("%i: I/O APIC", i);
 222                                 Log("\t.ID = %i", ents->IOAPIC.ID);
 223                                 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
 224                                 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
 225                                 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
 226                                 break;
 227                         case 3: // I/O Interrupt Assignment
 228                                 entSize = 8;
 229                                 Log("%i: I/O Interrupt Assignment", i);
 230                                 Log("\t.IntType = %i", ents->IOInt.IntType);
 231                                 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
 232                                 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
 233                                 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
 234                                 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
 235                                 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
 236                                 break;
 237                         case 4: // Local Interrupt Assignment
 238                                 entSize = 8;
 239                                 Log("%i: Local Interrupt Assignment", i);
 240                                 Log("\t.IntType = %i", ents->LocalInt.IntType);
 241                                 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
 242                                 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
 243                                 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
 244                                 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
 245                                 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
 246                                 break;
 247                         default:
 248                                 Log("%i: Unknown (%i)", i, ents->Type);
 249                                 break;
 250                         }
 251                         ents = (void*)( (Uint)ents + entSize );
 252                 }
 253
 254                 if( giNumCPUs > MAX_CPUS ) {
 255                         Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
 256                         giNumCPUs = MAX_CPUS;
 257                 }
 258
 259                 while( giNumInitingCPUs )
 260                         MM_FinishVirtualInit();
 261
 262                 Panic("Uh oh... MP Table Parsing is unimplemented\n");
 263         }
 264         else {
 265                 Log("No MP Table was found, assuming uniprocessor\n");
 266                 giNumCPUs = 1;
 267                 gTSSs = &gTSS0;
 268         }
 269         #else
 270         giNumCPUs = 1;
 271         gTSSs = &gTSS0;
 272         MM_FinishVirtualInit();
 273         #endif
 274
 275         #if USE_MP
 276         // Initialise Normal TSS(s)
 277         for(pos=0;pos<giNumCPUs;pos++)
 278         {
 279         #else
 280         pos = 0;
 281         #endif
 282                 gTSSs[pos].RSP0 = 0;    // Set properly by scheduler
 283                 gGDT[7+pos*2].LimitLow = sizeof(tTSS) & 0xFFFF;
 284                 gGDT[7+pos*2].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
 285                 gGDT[7+pos*2].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
 286                 gGDT[7+pos*2].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
 287                 gGDT[7+pos*2+1].DWord[0] = ((Uint)(&gTSSs[pos])) >> 32;
 288         #if USE_MP
 289         }
 290         for(pos=0;pos<giNumCPUs;pos++) {
 291                 __asm__ __volatile__ ("ltr %%ax"::"a"(0x38+pos*16));
 292         }
 293         #else
 294         __asm__ __volatile__ ("ltr %%ax"::"a"(0x38));
 295         #endif
 296
 297         // Set Debug registers
 298         __asm__ __volatile__ ("mov %0, %%db0" : : "r"(&gThreadZero));
 299         __asm__ __volatile__ ("mov %%rax, %%db1" : : "a"(0));
 300
 301         gaCPUs[0].Current = &gThreadZero;
 302
 303         gThreadZero.MemState.CR3 = (Uint)gInitialPML4 - KERNEL_BASE;
 304         gThreadZero.CurCPU = 0;
 305
 306         // Set timer frequency
 307         outb(0x43, 0x34);       // Set Channel 0, Low/High, Rate Generator
 308         outb(0x40, PIT_TIMER_DIVISOR&0xFF);     // Low Byte of Divisor
 309         outb(0x40, (PIT_TIMER_DIVISOR>>8)&0xFF);        // High Byte
 310
 311         // Create Per-Process Data Block
 312         if( !MM_Allocate(MM_PPD_CFG) )
 313         {
 314                 Warning("Oh, hell, Unable to allocate PPD for Thread#0");
 315         }
 316
 317         // Change Stacks
 318         Proc_ChangeStack();
 319
 320         Log("Multithreading initialised");
 321 }
 322
 323 #if USE_MP
 324 void MP_StartAP(int CPU)
 325 {
 326         Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
 327         // Set location of AP startup code and mark for a warm restart
 328         *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);
 329         *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
 330         outb(0x70, 0x0F);       outb(0x71, 0x0A);       // Warm Reset
 331         MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);
 332         giNumInitingCPUs ++;
 333 }
 334
 335 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
 336 {
 337         Uint32  addr = (Uint)gpMP_LocalAPIC + 0x300;
 338         Uint32  val;
 339
 340         // High
 341         val = (Uint)APICID << 24;
 342         Log("*%p = 0x%08x", addr+0x10, val);
 343         *(Uint32*)(addr+0x10) = val;
 344         // Low (and send)
 345         val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
 346         Log("*%p = 0x%08x", addr, val);
 347         *(Uint32*)addr = val;
 348 }
 349 #endif
 350
 351 /**
 352  * \fn void Proc_Start(void)
 353  * \brief Start process scheduler
 354  */
 355 void Proc_Start(void)
 356 {
 357         #if USE_MP
 358          int    i;
 359         #endif
 360
 361         #if USE_MP
 362         // Start APs
 363         for( i = 0; i < giNumCPUs; i ++ )
 364         {
 365                  int    tid;
 366                 if(i)   gaCPUs[i].Current = NULL;
 367
 368                 // Create Idle Task
 369                 if( (tid = Proc_Clone(0, 0)) == 0)
 370                 {
 371                         for(;;) HALT(); // Just yeilds
 372                 }
 373                 gaCPUs[i].IdleThread = Threads_GetThread(tid);
 374                 gaCPUs[i].IdleThread->ThreadName = "Idle Thread";
 375                 Threads_SetTickets( gaCPUs[i].IdleThread, 0 );  // Never called randomly
 376                 gaCPUs[i].IdleThread->Quantum = 1;      // 1 slice quantum
 377
 378
 379                 // Start the AP
 380                 if( i != giProc_BootProcessorID ) {
 381                         MP_StartAP( i );
 382                 }
 383         }
 384
 385         // BSP still should run the current task
 386         gaCPUs[0].Current = &gThreadZero;
 387
 388         // Start interrupts and wait for APs to come up
 389         Log("Waiting for APs to come up\n");
 390         __asm__ __volatile__ ("sti");
 391         while( giNumInitingCPUs )       __asm__ __volatile__ ("hlt");
 392         #else
 393         // Create Idle Task
 394         if(Proc_Clone(0) == 0)
 395         {
 396                 gaCPUs[0].IdleThread = Proc_GetCurThread();
 397                 gaCPUs[0].IdleThread->ThreadName = (char*)"Idle Thread";
 398                 Threads_SetPriority( gaCPUs[0].IdleThread, -1 );        // Never called randomly
 399                 gaCPUs[0].IdleThread->Quantum = 1;      // 1 slice quantum
 400                 for(;;) HALT(); // Just yeilds
 401         }
 402
 403         // Set current task
 404         gaCPUs[0].Current = &gThreadZero;
 405         gaCPUs[0].Current->CurCPU = 0;
 406
 407         // Start Interrupts (and hence scheduler)
 408         __asm__ __volatile__("sti");
 409         #endif
 410         MM_FinishVirtualInit();
 411         Log("Multithreading started");
 412 }
 413
 414 /**
 415  * \fn tThread *Proc_GetCurThread(void)
 416  * \brief Gets the current thread
 417  */
 418 tThread *Proc_GetCurThread(void)
 419 {
 420         #if USE_MP
 421         return gaCPUs[ GetCPUNum() ].Current;
 422         #else
 423         return gaCPUs[ 0 ].Current;
 424         #endif
 425 }
 426
 427 /**
 428  * \fn void Proc_ChangeStack(void)
 429  * \brief Swaps the current stack for a new one (in the proper stack reigon)
 430  */
 431 void Proc_ChangeStack(void)
 432 {
 433         Uint    rsp, rbp;
 434         Uint    tmp_rbp, old_rsp;
 435         Uint    curBase, newBase;
 436
 437         __asm__ __volatile__ ("mov %%rsp, %0":"=r"(rsp));
 438         __asm__ __volatile__ ("mov %%rbp, %0":"=r"(rbp));
 439
 440         old_rsp = rsp;
 441
 442         // Create new KStack
 443         newBase = MM_NewKStack();
 444         // Check for errors
 445         if(newBase == 0) {
 446                 Panic("What the?? Unable to allocate space for initial kernel stack");
 447                 return;
 448         }
 449
 450         curBase = (Uint)&gInitialKernelStack;
 451
 452         Log("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
 453
 454         // Get ESP as a used size
 455         rsp = curBase - rsp;
 456         Log("memcpy( %p, %p, 0x%x )", (void*)(newBase - rsp), (void*)(curBase - rsp), rsp );
 457         // Copy used stack
 458         memcpy( (void*)(newBase - rsp), (void*)(curBase - rsp), rsp );
 459         // Get ESP as an offset in the new stack
 460         rsp = newBase - rsp;
 461         // Adjust EBP
 462         rbp = newBase - (curBase - rbp);
 463
 464         Log("Update stack");
 465         // Repair EBPs & Stack Addresses
 466         // Catches arguments also, but may trash stack-address-like values
 467         for(tmp_rbp = rsp; tmp_rbp < newBase; tmp_rbp += sizeof(Uint))
 468         {
 469                 if(old_rsp < *(Uint*)tmp_rbp && *(Uint*)tmp_rbp < curBase)
 470                         *(Uint*)tmp_rbp += newBase - curBase;
 471         }
 472
 473         Log("Applying Changes");
 474         Proc_GetCurThread()->KernelStack = newBase;
 475         __asm__ __volatile__ ("mov %0, %%rsp"::"r"(rsp));
 476         __asm__ __volatile__ ("mov %0, %%rbp"::"r"(rbp));
 477 }
 478
 479 /**
 480  * \fn int Proc_Clone(Uint Flags)
 481  * \brief Clone the current process
 482  */
 483 int Proc_Clone(Uint Flags)
 484 {
 485         tThread *newThread;
 486         tThread *cur = Proc_GetCurThread();
 487         Uint    rip, rsp, rbp;
 488
 489         __asm__ __volatile__ ("mov %%rsp, %0": "=r"(rsp));
 490         __asm__ __volatile__ ("mov %%rbp, %0": "=r"(rbp));
 491
 492         newThread = Threads_CloneTCB(NULL, Flags);
 493         if(!newThread)  return -1;
 494
 495         Log("Proc_Clone: newThread = %p", newThread);
 496
 497         // Initialise Memory Space (New Addr space or kernel stack)
 498         if(Flags & CLONE_VM) {
 499                 Log("Proc_Clone: Cloning VM");
 500                 newThread->MemState.CR3 = MM_Clone();
 501                 newThread->KernelStack = cur->KernelStack;
 502 //              MAGIC_BREAK();
 503         } else {
 504                 Uint    tmp_rbp, old_rsp = rsp;
 505
 506                 // Set CR3
 507                 newThread->MemState.CR3 = cur->MemState.CR3;
 508
 509                 // Create new KStack
 510                 newThread->KernelStack = MM_NewKStack();
 511                 Log("Proc_Clone: newKStack = %p", newThread->KernelStack);
 512                 // Check for errors
 513                 if(newThread->KernelStack == 0) {
 514                         free(newThread);
 515                         return -1;
 516                 }
 517
 518                 // Get ESP as a used size
 519                 rsp = cur->KernelStack - rsp;
 520                 // Copy used stack
 521                 memcpy(
 522                         (void*)(newThread->KernelStack - rsp),
 523                         (void*)(cur->KernelStack - rsp),
 524                         rsp
 525                         );
 526                 // Get ESP as an offset in the new stack
 527                 rsp = newThread->KernelStack - rsp;
 528                 // Adjust EBP
 529                 rbp = newThread->KernelStack - (cur->KernelStack - rbp);
 530
 531                 // Repair EBPs & Stack Addresses
 532                 // Catches arguments also, but may trash stack-address-like values
 533                 for(tmp_rbp = rsp; tmp_rbp < newThread->KernelStack; tmp_rbp += sizeof(Uint))
 534                 {
 535                         if(old_rsp < *(Uint*)tmp_rbp && *(Uint*)tmp_rbp < cur->KernelStack)
 536                                 *(Uint*)tmp_rbp += newThread->KernelStack - cur->KernelStack;
 537                 }
 538         }
 539
 540         // Save core machine state
 541         newThread->SavedState.RSP = rsp;
 542         newThread->SavedState.RBP = rbp;
 543         rip = GetRIP();
 544         if(rip == SWITCH_MAGIC) {
 545                 outb(0x20, 0x20);       // ACK Timer and return as child
 546                 __asm__ __volatile__ ("sti");
 547 //              MAGIC_BREAK();
 548                 return 0;
 549         }
 550
 551         // Set EIP as parent
 552         newThread->SavedState.RIP = rip;
 553
 554         // Lock list and add to active
 555         Threads_AddActive(newThread);
 556
 557         return newThread->TID;
 558 }
 559
 560 /**
 561  * \fn int Proc_SpawnWorker(void)
 562  * \brief Spawns a new worker thread
 563  */
 564 int Proc_SpawnWorker(void)
 565 {
 566         tThread *new, *cur;
 567         Uint    rip, rsp, rbp;
 568
 569         cur = Proc_GetCurThread();
 570
 571         // Create new thread
 572         new = malloc( sizeof(tThread) );
 573         if(!new) {
 574                 Warning("Proc_SpawnWorker - Out of heap space!\n");
 575                 return -1;
 576         }
 577         memcpy(new, &gThreadZero, sizeof(tThread));
 578         // Set Thread ID
 579         new->TID = giNextTID++;
 580         // Create a new worker stack (in PID0's address space)
 581         // The stack is relocated by this code
 582         new->KernelStack = MM_NewWorkerStack();
 583
 584         // Get ESP and EBP based in the new stack
 585         __asm__ __volatile__ ("mov %%rsp, %0": "=r"(rsp));
 586         __asm__ __volatile__ ("mov %%rbp, %0": "=r"(rbp));
 587         rsp = new->KernelStack - (cur->KernelStack - rsp);
 588         rbp = new->KernelStack - (cur->KernelStack - rbp);
 589
 590         // Save core machine state
 591         new->SavedState.RSP = rsp;
 592         new->SavedState.RBP = rbp;
 593         rip = GetRIP();
 594         if(rip == SWITCH_MAGIC) {
 595                 outb(0x20, 0x20);       // ACK Timer and return as child
 596                 __asm__ __volatile__ ("sti");
 597                 return 0;
 598         }
 599
 600         // Set EIP as parent
 601         new->SavedState.RIP = rip;
 602         // Mark as active
 603         new->Status = THREAD_STAT_PREINIT;
 604         Threads_AddActive( new );
 605
 606         return new->TID;
 607 }
 608
 609 /**
 610  * \fn Uint Proc_MakeUserStack(void)
 611  * \brief Creates a new user stack
 612  */
 613 Uint Proc_MakeUserStack(void)
 614 {
 615          int    i;
 616         Uint    base = USER_STACK_TOP - USER_STACK_SZ;
 617
 618         // Check Prospective Space
 619         for( i = USER_STACK_SZ >> 12; i--; )
 620                 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
 621                         break;
 622
 623         if(i != -1)     return 0;
 624
 625         // Allocate Stack - Allocate incrementally to clean up MM_Dump output
 626         for( i = 0; i < USER_STACK_SZ/0x1000; i++ )
 627         {
 628                 if( !MM_Allocate( base + (i<<12) ) )
 629                 {
 630                         // Error
 631                         Log_Error("Proc", "Unable to allocate user stack (%i pages requested)", USER_STACK_SZ/0x1000);
 632                         while( i -- )
 633                                 MM_Deallocate( base + (i<<12) );
 634                         return 0;
 635                 }
 636         }
 637
 638         return base + USER_STACK_SZ;
 639 }
 640
 641
 642 /**
 643  * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
 644  * \brief Starts a user task
 645  */
 646 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
 647 {
 648         Uint    *stack = (void*)Proc_MakeUserStack();
 649          int    i;
 650         Uint    delta;
 651         Uint16  ss, cs;
 652
 653         LOG("stack = 0x%x", stack);
 654
 655         // Copy Arguments
 656         stack = (void*)( (Uint)stack - DataSize );
 657         memcpy( stack, ArgV, DataSize );
 658
 659         // Adjust Arguments and environment
 660         delta = (Uint)stack - (Uint)ArgV;
 661         ArgV = (char**)stack;
 662         for( i = 0; ArgV[i]; i++ )      ArgV[i] += delta;
 663         i ++;
 664         EnvP = &ArgV[i];
 665         for( i = 0; EnvP[i]; i++ )      EnvP[i] += delta;
 666
 667         // User Mode Segments
 668         ss = 0x23;      cs = 0x1B;
 669
 670         // Arguments
 671         *--stack = (Uint)EnvP;
 672         *--stack = (Uint)ArgV;
 673         *--stack = (Uint)ArgC;
 674         while(*Bases)
 675                 *--stack = *Bases++;
 676         *--stack = 0;   // Return Address
 677
 678         Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
 679 }
 680
 681 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
 682 {
 683         Uint    *stack = (void*)Stack;
 684         *--stack = SS;          //Stack Segment
 685         *--stack = Stack;       //Stack Pointer
 686         *--stack = Flags;       //EFLAGS (Resvd (0x2) and IF (0x20))
 687         *--stack = CS;          //Code Segment
 688         *--stack = IP;  //EIP
 689         //PUSHAD
 690         *--stack = 0xAAAAAAAA;  // eax
 691         *--stack = 0xCCCCCCCC;  // ecx
 692         *--stack = 0xDDDDDDDD;  // edx
 693         *--stack = 0xBBBBBBBB;  // ebx
 694         *--stack = 0xD1D1D1D1;  // edi
 695         *--stack = 0x54545454;  // rsp - NOT POPED
 696         *--stack = 0x51515151;  // esi
 697         *--stack = 0xB4B4B4B4;  // rbp
 698         //Individual PUSHs
 699         *--stack = SS;  // ds
 700
 701         __asm__ __volatile__ (
 702         "mov %%rax,%%rsp;\n\t"  // Set stack pointer
 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
 733         return 0;
 734 }
 735
 736 /**
 737  * \brief Calls a signal handler in user mode
 738  * \note Used for signals
 739  */
 740 void Proc_CallFaultHandler(tThread *Thread)
 741 {
 742         // Rewinds the stack and calls the user function
 743         // Never returns
 744         __asm__ __volatile__ ("mov %0, %%rbp;\n\tcall Proc_ReturnToUser" :: "r"(Thread->FaultHandler));
 745         for(;;);
 746 }
 747
 748 void Proc_DumpThreadCPUState(tThread *Thread)
 749 {
 750         Log("  At %04x:%016llx", Thread->SavedState.UserCS, Thread->SavedState.UserRIP);
 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    rsp, rbp, rip;
 760         tThread *thread;
 761
 762         if( CPU == 0 )
 763                 Time_UpdateTimestamp();
 764
 765         // If the spinlock is set, let it complete
 766         if(IS_LOCKED(&glThreadListLock))        return;
 767
 768         // Get current thread
 769         thread = gaCPUs[CPU].Current;
 770
 771         if( thread )
 772         {
 773                 tRegs   *regs;
 774                 // Reduce remaining quantum and continue timeslice if non-zero
 775                 if(thread->Remaining--) return;
 776                 // Reset quantum for next call
 777                 thread->Remaining = thread->Quantum;
 778
 779                 // Get machine state
 780                 __asm__ __volatile__ ("mov %%rsp, %0":"=r"(rsp));
 781                 __asm__ __volatile__ ("mov %%rbp, %0":"=r"(rbp));
 782                 rip = GetRIP();
 783                 if(rip == SWITCH_MAGIC) return; // Check if a switch happened
 784
 785                 // Save machine state
 786                 thread->SavedState.RSP = rsp;
 787                 thread->SavedState.RBP = rbp;
 788                 thread->SavedState.RIP = rip;
 789
 790                 // TODO: Make this more stable somehow
 791                 regs = (tRegs*)(rbp+(2+1)*8);   // RBP,Ret + CurThread
 792                 thread->SavedState.UserCS = regs->CS;
 793                 thread->SavedState.UserRIP = regs->RIP;
 794         }
 795
 796         #if BREAK_ON_SWITCH
 797         {
 798         tThread *oldthread = thread;
 799         #endif
 800
 801         // Get next thread
 802         thread = Threads_GetNextToRun(CPU, thread);
 803
 804         // Error Check
 805         if(thread == NULL) {
 806                 thread = gaCPUs[CPU].IdleThread;
 807                 //Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
 808 //              LogF("Zzzzz.\n");
 809                 //return;
 810         }
 811         if(thread == NULL ) {
 812                 return ;
 813         }
 814         #if BREAK_ON_SWITCH
 815         if( thread != oldthread ) {
 816                 MAGIC_BREAK();
 817         }
 818         }
 819         #endif
 820
 821         #if DEBUG_TRACE_SWITCH
 822         LogF("Switching to task %i, CR3 = 0x%x, RIP = %p",
 823                 thread->TID,
 824                 thread->MemState.CR3,
 825                 thread->SavedState.RIP
 826                 );
 827         #endif
 828
 829
 830         if(CPU > MAX_CPUS)
 831                 LogF("CPU = %i", CPU);
 832         // Set current thread
 833         gaCPUs[CPU].Current = thread;
 834
 835         // Update Kernel Stack pointer
 836         gTSSs[CPU].RSP0 = thread->KernelStack-4;
 837
 838         // Switch threads
 839         __asm__ __volatile__ (
 840                 "mov %4, %%cr3\n\t"
 841                 "mov %1, %%rsp\n\t"     // Restore RSP
 842                 "mov %2, %%rbp\n\t"     // and RBP
 843                 "jmp *%3" : :   // And return to where we saved state (Proc_Clone or Proc_Scheduler)
 844                 "a"(SWITCH_MAGIC), "r"(thread->SavedState.RSP),
 845                 "r"(thread->SavedState.RBP), "r"(thread->SavedState.RIP),
 846                 "r"(thread->MemState.CR3)
 847                 );
 848         for(;;);        // Shouldn't reach here
 849 }
 850
 851 // === EXPORTS ===
 852 EXPORT(Proc_SpawnWorker);