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         0       // Break into bochs debugger on a task switch
  21
  22 // === CONSTANTS ===
  23
  24 // === TYPES ===
  25 typedef struct sCPU
  26 {
  27         Uint8   APICID;
  28         Uint8   State;  // 0: Unavaliable, 1: Idle, 2: Active
  29         Uint16  Resvd;
  30         tThread *Current;
  31         tThread *IdleThread;
  32 }       tCPU;
  33
  34 // === IMPORTS ===
  35 extern tGDT     gGDT[];
  36 extern void     APStartup(void);        // 16-bit AP startup code
  37
  38 extern Uint     GetRIP(void);   // start.asm
  39 extern Uint     SaveState(Uint *RSP, Uint *Regs);
  40 extern Uint     Proc_CloneInt(Uint *RSP, Uint *CR3);
  41 extern void     NewTaskHeader(void);    // Actually takes cdecl args
  42
  43 extern Uint64   gInitialPML4[512];      // start.asm
  44 extern int      giNumCPUs;
  45 extern int      giNextTID;
  46 extern int      giTotalTickets;
  47 extern int      giNumActiveThreads;
  48 extern tThread  gThreadZero;
  49 extern void     Threads_Dump(void);
  50 extern void     Proc_ReturnToUser(tVAddr Handler, tVAddr KStackTop, int Argument);
  51 extern void     Time_UpdateTimestamp(void);
  52 extern void     SwitchTasks(Uint NewSP, Uint *OldSP, Uint NewIP, Uint *OldIO, Uint CR3);
  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_IdleTask(void *unused);
  61 //void  Proc_Start(void);
  62 //tThread       *Proc_GetCurThread(void);
  63 // int  Proc_NewKThread(void (*Fcn)(void*), void *Data);
  64 // int  Proc_Clone(Uint *Err, Uint Flags);
  65 // int  Proc_SpawnWorker(void);
  66 Uint    Proc_MakeUserStack(void);
  67 //void  Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize);
  68 void    Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP) NORETURN;
  69  int    Proc_Demote(Uint *Err, int Dest, tRegs *Regs);
  70 //void  Proc_CallFaultHandler(tThread *Thread);
  71 //void  Proc_DumpThreadCPUState(tThread *Thread);
  72 //void  Proc_Reschedule(void);
  73 void    Proc_Scheduler(int CPU, Uint RSP, Uint RIP);
  74
  75 // === GLOBALS ===
  76 //!\brief Used by desctab.asm in SyscallStub
  77 const int ci_offsetof_tThread_KernelStack = offsetof(tThread, KernelStack);
  78 // --- Multiprocessing ---
  79 #if USE_MP
  80 volatile int    giNumInitingCPUs = 0;
  81 tMPInfo *gMPFloatPtr = NULL;
  82 tAPIC   *gpMP_LocalAPIC = NULL;
  83 Uint8   gaAPIC_to_CPU[256] = {0};
  84 #endif
  85 tCPU    gaCPUs[MAX_CPUS];
  86 tTSS    *gTSSs = NULL;
  87 tTSS    gTSS0 = {0};
  88 // --- Error Recovery ---
  89 Uint32  gaDoubleFaultStack[1024];
  90
  91 // === CODE ===
  92 /**
  93  * \fn void ArchThreads_Init(void)
  94  * \brief Starts the process scheduler
  95  */
  96 void ArchThreads_Init(void)
  97 {
  98         Uint    pos = 0;
  99
 100         #if USE_MP
 101         tMPTable        *mptable;
 102
 103         // Mark BSP as active
 104         gaCPUs[0].State = 2;
 105
 106         // -- Initialise Multiprocessing
 107         // Find MP Floating Table
 108         // - EBDA/Last 1Kib (640KiB)
 109         for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
 110                 if( *(Uint*)(pos) == MPPTR_IDENT ) {
 111                         Log("Possible %p", pos);
 112                         if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 113                         gMPFloatPtr = (void*)pos;
 114                         break;
 115                 }
 116         }
 117         // - Last KiB (512KiB base mem)
 118         if(!gMPFloatPtr) {
 119                 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); 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         }
 128         // - BIOS ROM
 129         if(!gMPFloatPtr) {
 130                 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); 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
 140         // If the MP Table Exists, parse it
 141         if(gMPFloatPtr)
 142         {
 143                  int    i;
 144                 tMPTable_Ent    *ents;
 145                 Log("gMPFloatPtr = %p", gMPFloatPtr);
 146                 Log("*gMPFloatPtr = {");
 147                 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
 148                 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
 149                 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
 150                 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
 151                 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
 152                 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
 153                         gMPFloatPtr->Features[0],       gMPFloatPtr->Features[1],
 154                         gMPFloatPtr->Features[2],       gMPFloatPtr->Features[3],
 155                         gMPFloatPtr->Features[4]
 156                         );
 157                 Log("}");
 158
 159                 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
 160                 Log("mptable = %p", mptable);
 161                 Log("*mptable = {");
 162                 Log("\t.Sig = 0x%08x", mptable->Sig);
 163                 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
 164                 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
 165                 Log("\t.Checksum = 0x%02x", mptable->Checksum);
 166                 Log("\t.OEMID = '%8c'", mptable->OemID);
 167                 Log("\t.ProductID = '%8c'", mptable->ProductID);
 168                 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
 169                 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
 170                 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
 171                 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
 172                 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
 173                 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
 174                 Log("}");
 175
 176                 gpMP_LocalAPIC = (void*)MM_MapHWPage(mptable->LocalAPICMemMap, 1);
 177
 178                 ents = mptable->Entries;
 179                 giNumCPUs = 0;
 180
 181                 for( i = 0; i < mptable->EntryCount; i ++ )
 182                 {
 183                          int    entSize = 0;
 184                         switch( ents->Type )
 185                         {
 186                         case 0: // Processor
 187                                 entSize = 20;
 188                                 Log("%i: Processor", i);
 189                                 Log("\t.APICID = %i", ents->Proc.APICID);
 190                                 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
 191                                 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
 192                                 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
 193                                 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
 194
 195
 196                                 if( !(ents->Proc.CPUFlags & 1) ) {
 197                                         Log("DISABLED");
 198                                         break;
 199                                 }
 200
 201                                 // Check if there is too many processors
 202                                 if(giNumCPUs >= MAX_CPUS) {
 203                                         giNumCPUs ++;   // If `giNumCPUs` > MAX_CPUS later, it will be clipped
 204                                         break;
 205                                 }
 206
 207                                 // Initialise CPU Info
 208                                 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
 209                                 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
 210                                 gaCPUs[giNumCPUs].State = 0;
 211                                 giNumCPUs ++;
 212
 213                                 // Send IPI
 214                                 if( !(ents->Proc.CPUFlags & 2) )
 215                                 {
 216                                         MP_StartAP( giNumCPUs-1 );
 217                                 }
 218
 219                                 break;
 220                         case 1: // Bus
 221                                 entSize = 8;
 222                                 Log("%i: Bus", i);
 223                                 Log("\t.ID = %i", ents->Bus.ID);
 224                                 Log("\t.TypeString = '%6c'", ents->Bus.TypeString);
 225                                 break;
 226                         case 2: // I/O APIC
 227                                 entSize = 8;
 228                                 Log("%i: I/O APIC", i);
 229                                 Log("\t.ID = %i", ents->IOAPIC.ID);
 230                                 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
 231                                 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
 232                                 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
 233                                 break;
 234                         case 3: // I/O Interrupt Assignment
 235                                 entSize = 8;
 236                                 Log("%i: I/O Interrupt Assignment", i);
 237                                 Log("\t.IntType = %i", ents->IOInt.IntType);
 238                                 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
 239                                 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
 240                                 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
 241                                 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
 242                                 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
 243                                 break;
 244                         case 4: // Local Interrupt Assignment
 245                                 entSize = 8;
 246                                 Log("%i: Local Interrupt Assignment", i);
 247                                 Log("\t.IntType = %i", ents->LocalInt.IntType);
 248                                 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
 249                                 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
 250                                 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
 251                                 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
 252                                 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
 253                                 break;
 254                         default:
 255                                 Log("%i: Unknown (%i)", i, ents->Type);
 256                                 break;
 257                         }
 258                         ents = (void*)( (Uint)ents + entSize );
 259                 }
 260
 261                 if( giNumCPUs > MAX_CPUS ) {
 262                         Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
 263                         giNumCPUs = MAX_CPUS;
 264                 }
 265
 266                 while( giNumInitingCPUs )
 267                         MM_FinishVirtualInit();
 268
 269                 Panic("Uh oh... MP Table Parsing is unimplemented\n");
 270         }
 271         else {
 272                 Log("No MP Table was found, assuming uniprocessor\n");
 273                 giNumCPUs = 1;
 274                 gTSSs = &gTSS0;
 275         }
 276         #else
 277         giNumCPUs = 1;
 278         gTSSs = &gTSS0;
 279         MM_FinishVirtualInit();
 280         #endif
 281
 282         #if USE_MP
 283         // Initialise Normal TSS(s)
 284         for(pos=0;pos<giNumCPUs;pos++)
 285         {
 286         #else
 287         pos = 0;
 288         #endif
 289                 gTSSs[pos].RSP0 = 0;    // Set properly by scheduler
 290                 gGDT[7+pos*2].LimitLow = sizeof(tTSS) & 0xFFFF;
 291                 gGDT[7+pos*2].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
 292                 gGDT[7+pos*2].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
 293                 gGDT[7+pos*2].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
 294                 gGDT[7+pos*2+1].DWord[0] = ((Uint)(&gTSSs[pos])) >> 32;
 295         #if USE_MP
 296         }
 297         for(pos=0;pos<giNumCPUs;pos++) {
 298                 __asm__ __volatile__ ("ltr %%ax"::"a"(0x38+pos*16));
 299         }
 300         #else
 301         __asm__ __volatile__ ("ltr %%ax"::"a"(0x38));
 302         #endif
 303
 304         // Set Debug registers
 305         __asm__ __volatile__ ("mov %0, %%db0" : : "r"(&gThreadZero));
 306         __asm__ __volatile__ ("mov %%rax, %%db1" : : "a"(0));
 307
 308         gaCPUs[0].Current = &gThreadZero;
 309
 310         gThreadZero.MemState.CR3 = (Uint)gInitialPML4 - KERNEL_BASE;
 311         gThreadZero.CurCPU = 0;
 312         gThreadZero.KernelStack = 0xFFFFA00000000000 + KERNEL_STACK_SIZE;
 313
 314         // Set timer frequency
 315         outb(0x43, 0x34);       // Set Channel 0, Low/High, Rate Generator
 316         outb(0x40, PIT_TIMER_DIVISOR&0xFF);     // Low Byte of Divisor
 317         outb(0x40, (PIT_TIMER_DIVISOR>>8)&0xFF);        // High Byte
 318
 319         // Create Per-Process Data Block
 320         if( !MM_Allocate(MM_PPD_CFG) )
 321         {
 322                 Warning("Oh, hell, Unable to allocate PPD for Thread#0");
 323         }
 324
 325         Log_Log("Proc", "Multithreading initialised");
 326 }
 327
 328 #if USE_MP
 329 void MP_StartAP(int CPU)
 330 {
 331         Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
 332         // Set location of AP startup code and mark for a warm restart
 333         *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);
 334         *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
 335         outb(0x70, 0x0F);       outb(0x71, 0x0A);       // Warm Reset
 336         MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);
 337         giNumInitingCPUs ++;
 338 }
 339
 340 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
 341 {
 342         Uint32  addr = (Uint)gpMP_LocalAPIC + 0x300;
 343         Uint32  val;
 344
 345         // High
 346         val = (Uint)APICID << 24;
 347         Log("*%p = 0x%08x", addr+0x10, val);
 348         *(Uint32*)(addr+0x10) = val;
 349         // Low (and send)
 350         val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
 351         Log("*%p = 0x%08x", addr, val);
 352         *(Uint32*)addr = val;
 353 }
 354 #endif
 355
 356 /**
 357  * \brief Idle task
 358  */
 359 void Proc_IdleTask(void *ptr)
 360 {
 361         tCPU    *cpu = ptr;
 362         cpu->IdleThread = Proc_GetCurThread();
 363         cpu->IdleThread->ThreadName = (char*)"Idle Thread";
 364         Threads_SetPriority( cpu->IdleThread, -1 );     // Never called randomly
 365         cpu->IdleThread->Quantum = 1;   // 1 slice quantum
 366         for(;;) {
 367                 HALT(); // Just yeilds
 368                 Threads_Yield();
 369         }
 370 }
 371
 372 /**
 373  * \fn void Proc_Start(void)
 374  * \brief Start process scheduler
 375  */
 376 void Proc_Start(void)
 377 {
 378         #if USE_MP
 379          int    i;
 380         #endif
 381
 382         #if USE_MP
 383         // Start APs
 384         for( i = 0; i < giNumCPUs; i ++ )
 385         {
 386                  int    tid;
 387                 if(i)   gaCPUs[i].Current = NULL;
 388
 389                 Proc_NewKThread(Proc_IdleTask, &gaCPUs[i]);
 390
 391                 // Create Idle Task
 392                 gaCPUs[i].IdleThread = Threads_GetThread(tid);
 393
 394
 395                 // Start the AP
 396                 if( i != giProc_BootProcessorID ) {
 397                         MP_StartAP( i );
 398                 }
 399         }
 400
 401         // BSP still should run the current task
 402         gaCPUs[0].Current = &gThreadZero;
 403
 404         // Start interrupts and wait for APs to come up
 405         Log("Waiting for APs to come up\n");
 406         __asm__ __volatile__ ("sti");
 407         while( giNumInitingCPUs )       __asm__ __volatile__ ("hlt");
 408         #else
 409         Proc_NewKThread(Proc_IdleTask, &gaCPUs[0]);
 410
 411         // Start Interrupts (and hence scheduler)
 412         __asm__ __volatile__("sti");
 413         #endif
 414         MM_FinishVirtualInit();
 415         Log_Log("Proc", "Multithreading started");
 416 }
 417
 418 /**
 419  * \fn tThread *Proc_GetCurThread(void)
 420  * \brief Gets the current thread
 421  */
 422 tThread *Proc_GetCurThread(void)
 423 {
 424         #if USE_MP
 425         return gaCPUs[ GetCPUNum() ].Current;
 426         #else
 427         return gaCPUs[ 0 ].Current;
 428         #endif
 429 }
 430
 431 /*
 432  *
 433  */
 434 void Proc_ClearThread(tThread *Thread)
 435 {
 436         Log_Warning("Proc", "TODO: Nuke address space etc");
 437 }
 438
 439 /**
 440  * \brief Create a new kernel thread
 441  */
 442 int Proc_NewKThread(void (*Fcn)(void*), void *Data)
 443 {
 444         Uint    rsp;
 445         tThread *newThread, *cur;
 446
 447         cur = Proc_GetCurThread();
 448         newThread = Threads_CloneTCB(0);
 449         if(!newThread)  return -1;
 450
 451         // Set CR3
 452         newThread->MemState.CR3 = cur->MemState.CR3;
 453
 454         // Create new KStack
 455         newThread->KernelStack = MM_NewKStack();
 456         // Check for errors
 457         if(newThread->KernelStack == 0) {
 458                 free(newThread);
 459                 return -1;
 460         }
 461
 462         rsp = newThread->KernelStack;
 463         *(Uint*)(rsp-=8) = (Uint)Data;  // Data (shadowed)
 464         *(Uint*)(rsp-=8) = 1;   // Number of params
 465         *(Uint*)(rsp-=8) = (Uint)Fcn;   // Function to call
 466         *(Uint*)(rsp-=8) = (Uint)newThread;     // Thread ID
 467
 468         newThread->SavedState.RSP = rsp;
 469         newThread->SavedState.RIP = (Uint)&NewTaskHeader;
 470 //      Log("New (KThread) %p, rsp = %p\n", newThread->SavedState.RIP, newThread->SavedState.RSP);
 471
 472 //      MAGIC_BREAK();
 473         Threads_AddActive(newThread);
 474
 475         return newThread->TID;
 476 }
 477
 478 /**
 479  * \fn int Proc_Clone(Uint Flags)
 480  * \brief Clone the current process
 481  */
 482 int Proc_Clone(Uint Flags)
 483 {
 484         tThread *newThread, *cur = Proc_GetCurThread();
 485         Uint    rip;
 486
 487         // Sanity check
 488         if( !(Flags & CLONE_VM) ) {
 489                 Log_Error("Proc", "Proc_Clone: Don't leave CLONE_VM unset, use Proc_NewKThread instead");
 490                 return -1;
 491         }
 492
 493         // Create new TCB
 494         newThread = Threads_CloneTCB(Flags);
 495         if(!newThread)  return -1;
 496
 497         // Save core machine state
 498         rip = Proc_CloneInt(&newThread->SavedState.RSP, &newThread->MemState.CR3);
 499         if(rip == 0)    return 0;       // Child
 500         newThread->KernelStack = cur->KernelStack;
 501         newThread->SavedState.RIP = rip;
 502
 503         // DEBUG
 504         #if 0
 505         Log("New (Clone) %p, rsp = %p, cr3 = %p", rip, newThread->SavedState.RSP, newThread->MemState.CR3);
 506         {
 507                 Uint cr3;
 508                 __asm__ __volatile__ ("mov %%cr3, %0" : "=r" (cr3));
 509                 Log("Current CR3 = 0x%x, PADDR(RSP) = 0x%x", cr3, MM_GetPhysAddr(newThread->SavedState.RSP));
 510         }
 511         #endif
 512         // /DEBUG
 513
 514         // Lock list and add to active
 515         Threads_AddActive(newThread);
 516
 517         return newThread->TID;
 518 }
 519
 520 /**
 521  * \fn int Proc_SpawnWorker(void)
 522  * \brief Spawns a new worker thread
 523  */
 524 int Proc_SpawnWorker(void (*Fcn)(void*), void *Data)
 525 {
 526         tThread *new, *cur;
 527         Uint    stack_contents[4];
 528
 529         cur = Proc_GetCurThread();
 530
 531         // Create new thread
 532         new = malloc( sizeof(tThread) );
 533         if(!new) {
 534                 Warning("Proc_SpawnWorker - Out of heap space!\n");
 535                 return -1;
 536         }
 537         memcpy(new, &gThreadZero, sizeof(tThread));
 538         // Set Thread ID
 539         new->TID = giNextTID++;
 540
 541         // Create the stack contents
 542         stack_contents[3] = (Uint)Data;
 543         stack_contents[2] = 1;
 544         stack_contents[1] = (Uint)Fcn;
 545         stack_contents[0] = (Uint)new;
 546
 547         // Create a new worker stack (in PID0's address space)
 548         // The stack is relocated by this code
 549         new->KernelStack = MM_NewWorkerStack(stack_contents, sizeof(stack_contents));
 550
 551         new->SavedState.RSP = new->KernelStack - sizeof(stack_contents);
 552         new->SavedState.RIP = (Uint)&NewTaskHeader;
 553
 554 //      Log("New (Worker) %p, rsp = %p\n", new->SavedState.RIP, new->SavedState.RSP);
 555
 556         // Mark as active
 557         new->Status = THREAD_STAT_PREINIT;
 558         Threads_AddActive( new );
 559
 560         return new->TID;
 561 }
 562
 563 /**
 564  * \brief Creates a new user stack
 565  */
 566 Uint Proc_MakeUserStack(void)
 567 {
 568          int    i;
 569         Uint    base = USER_STACK_TOP - USER_STACK_SZ;
 570
 571         // Check Prospective Space
 572         for( i = USER_STACK_SZ >> 12; i--; )
 573         {
 574                 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
 575                         break;
 576         }
 577
 578         if(i != -1)     return 0;
 579
 580         // Allocate Stack - Allocate incrementally to clean up MM_Dump output
 581         for( i = 0; i < (USER_STACK_SZ-USER_STACK_PREALLOC)/0x1000; i++ )
 582         {
 583                 MM_AllocateZero( base + (i<<12) );
 584         }
 585         for( ; i < USER_STACK_SZ/0x1000; i++ )
 586         {
 587                 tPAddr  alloc = MM_Allocate( base + (i<<12) );
 588                 if( !alloc )
 589                 {
 590                         // Error
 591                         Log_Error("Proc", "Unable to allocate user stack (%i pages requested)", USER_STACK_SZ/0x1000);
 592                         while( i -- )
 593                                 MM_Deallocate( base + (i<<12) );
 594                         return 0;
 595                 }
 596         }
 597
 598         return base + USER_STACK_SZ;
 599 }
 600
 601
 602 void Proc_StartUser(Uint Entrypoint, Uint Base, int ArgC, char **ArgV, int DataSize)
 603 {
 604         Uint    *stack;
 605         char    **envp;
 606          int    i;
 607         Uint    delta;
 608         Uint16  ss, cs;
 609
 610
 611         // Copy Arguments
 612         stack = (void*)Proc_MakeUserStack();
 613         if(!stack) {
 614                 Log_Error("Proc", "Unable to create user stack!");
 615                 Threads_Exit(0, -1);
 616         }
 617         stack -= (DataSize+7)/8;
 618         LOG("stack = 0x%x", stack);
 619         Log("stack = %p, DataSize = %i", stack, DataSize);
 620         memcpy( stack, ArgV, DataSize );
 621         free(ArgV);
 622
 623         // Adjust Arguments and environment
 624         delta = (Uint)stack - (Uint)ArgV;
 625         ArgV = (char**)stack;
 626         for( i = 0; ArgV[i]; i++ )      ArgV[i] += delta;
 627         envp = &ArgV[i+1];
 628         for( i = 0; envp[i]; i++ )      envp[i] += delta;
 629
 630         // User Mode Segments
 631         // 0x2B = 64-bit
 632         ss = 0x23;      cs = 0x2B;
 633
 634         // Arguments
 635         *--stack = (Uint)envp;
 636         *--stack = (Uint)ArgV;
 637         *--stack = (Uint)ArgC;
 638         *--stack = Base;
 639
 640         Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
 641 }
 642
 643 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
 644 {
 645         if( !(CS == 0x1B || CS == 0x2B) || SS != 0x23 ) {
 646                 Log_Error("Proc", "Proc_StartProcess: CS / SS are not valid (%x, %x)",
 647                         CS, SS);
 648                 Threads_Exit(0, -1);
 649         }
 650 //      Log("Proc_StartProcess: (SS=%x, Stack=%p, Flags=%x, CS=%x, IP=%p)", SS, Stack, Flags, CS, IP);
 651 //      MM_DumpTables(0, USER_MAX);
 652         if(CS == 0x1B)
 653         {
 654                 // 32-bit return
 655                 __asm__ __volatile__ (
 656                         "mov %0, %%rsp;\n\t"    // Set stack pointer
 657                         "mov %2, %%r11;\n\t"    // Set RFLAGS
 658                         "sysret;\n\t"
 659                         : : "r" (Stack), "c" (IP), "r" (Flags)
 660                         );
 661         }
 662         else
 663         {
 664                 // 64-bit return
 665                 __asm__ __volatile__ (
 666                         "mov %0, %%rsp;\n\t"    // Set stack pointer
 667                         "mov %2, %%r11;\n\t"    // Set RFLAGS
 668                         "sysretq;\n\t"
 669                         : : "r" (Stack), "c" (IP), "r" (Flags)
 670                         );
 671         }
 672         for(;;);
 673 }
 674
 675 /**
 676  * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
 677  * \brief Demotes a process to a lower permission level
 678  * \param Err   Pointer to user's errno
 679  * \param Dest  New Permission Level
 680  * \param Regs  Pointer to user's register structure
 681  */
 682 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
 683 {
 684          int    cpl = Regs->CS & 3;
 685         // Sanity Check
 686         if(Dest > 3 || Dest < 0) {
 687                 *Err = -EINVAL;
 688                 return -1;
 689         }
 690
 691         // Permission Check
 692         if(cpl > Dest) {
 693                 *Err = -EACCES;
 694                 return -1;
 695         }
 696
 697         // Change the Segment Registers
 698         Regs->CS = (((Dest+1)<<4) | Dest) - 8;
 699         Regs->SS = ((Dest+1)<<4) | Dest;
 700
 701         return 0;
 702 }
 703
 704 /**
 705  * \brief Calls a signal handler in user mode
 706  * \note Used for signals
 707  */
 708 void Proc_CallFaultHandler(tThread *Thread)
 709 {
 710         // Never returns
 711         Proc_ReturnToUser(Thread->FaultHandler, Thread->KernelStack, Thread->CurFaultNum);
 712         for(;;);
 713 }
 714
 715 void Proc_DumpThreadCPUState(tThread *Thread)
 716 {
 717         Log("  At %04x:%016llx", Thread->SavedState.UserCS, Thread->SavedState.UserRIP);
 718 }
 719
 720 void Proc_Reschedule(void)
 721 {
 722         tThread *nextthread, *curthread;
 723          int    cpu = GetCPUNum();
 724
 725         // TODO: Wait for it?
 726         if(IS_LOCKED(&glThreadListLock))        return;
 727
 728         curthread = gaCPUs[cpu].Current;
 729
 730         nextthread = Threads_GetNextToRun(cpu, curthread);
 731
 732         if(nextthread == curthread)     return ;
 733         if(!nextthread)
 734                 nextthread = gaCPUs[cpu].IdleThread;
 735         if(!nextthread)
 736                 return ;
 737
 738         #if DEBUG_TRACE_SWITCH
 739         LogF("\nSwitching to task CR3 = 0x%x, RIP = %p, RSP = %p - %i (%s)\n",
 740                 nextthread->MemState.CR3,
 741                 nextthread->SavedState.RIP,
 742                 nextthread->SavedState.RSP,
 743                 nextthread->TID,
 744                 nextthread->ThreadName
 745                 );
 746         #endif
 747
 748         // Update CPU state
 749         gaCPUs[cpu].Current = nextthread;
 750         gTSSs[cpu].RSP0 = nextthread->KernelStack-4;
 751         __asm__ __volatile__ ("mov %0, %%db0" : : "r" (nextthread));
 752
 753         SwitchTasks(
 754                 nextthread->SavedState.RSP, &curthread->SavedState.RSP,
 755                 nextthread->SavedState.RIP, &curthread->SavedState.RIP,
 756                 nextthread->MemState.CR3
 757                 );
 758         return ;
 759 }
 760
 761 /**
 762  * \fn void Proc_Scheduler(int CPU)
 763  * \brief Swap current thread and clears dead threads
 764  */
 765 void Proc_Scheduler(int CPU, Uint RSP, Uint RIP)
 766 {
 767 #if 0
 768         {
 769         tThread *thread;
 770
 771         // If the spinlock is set, let it complete
 772         if(IS_LOCKED(&glThreadListLock))        return;
 773
 774         // Get current thread
 775         thread = gaCPUs[CPU].Current;
 776
 777         if( thread )
 778         {
 779                 tRegs   *regs;
 780                 // Reduce remaining quantum and continue timeslice if non-zero
 781                 if(thread->Remaining--) return;
 782                 // Reset quantum for next call
 783                 thread->Remaining = thread->Quantum;
 784
 785                 // TODO: Make this more stable somehow
 786                 {
 787                         regs = (tRegs*)(RSP+(1)*8);     // CurThread
 788                         thread->SavedState.UserCS = regs->CS;
 789                         thread->SavedState.UserRIP = regs->RIP;
 790                 }
 791         }
 792
 793         // ACK Timer here?
 794
 795         Proc_Reschedule();
 796         }
 797 #endif
 798 }
 799
 800 // === EXPORTS ===
 801 EXPORT(Proc_SpawnWorker);