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 <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
  18 // === CONSTANTS ===
  19 #define SWITCH_MAGIC    0x55ECAFFF##FFFACE55    // There is no code in this area
  20 // Base is 1193182
  21 #define TIMER_DIVISOR   11931   //~100Hz
  22
  23 // === TYPES ===
  24 typedef struct sCPU
  25 {
  26         Uint8   APICID;
  27         Uint8   State;  // 0: Unavaliable, 1: Idle, 2: Active
  28         Uint16  Resvd;
  29         tThread *Current;
  30         tThread *IdleThread;
  31 }       tCPU;
  32
  33 // === IMPORTS ===
  34 extern tGDT     gGDT[];
  35 extern void     APStartup(void);        // 16-bit AP startup code
  36 extern Uint     GetRIP(void);   // start.asm
  37 extern Uint64   gInitialPML4[512];      // start.asm
  38 extern char     gInitialKernelStack[];
  39 extern tSpinlock        glThreadListLock;
  40 extern int      giNumCPUs;
  41 extern int      giNextTID;
  42 extern int      giTotalTickets;
  43 extern int      giNumActiveThreads;
  44 extern tThread  gThreadZero;
  45 //extern tThread        *Threads_GetNextToRun(int CPU);
  46 extern void     Threads_Dump(void);
  47 extern tThread  *Threads_CloneTCB(Uint *Err, Uint Flags);
  48 extern void     Proc_ReturnToUser(void);
  49 extern int      GetCPUNum(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 void    Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
  62 void    Proc_CallFaultHandler(tThread *Thread);
  63 void    Proc_Scheduler(int CPU);
  64
  65 // === GLOBALS ===
  66 // --- Multiprocessing ---
  67 #if USE_MP
  68 volatile int    giNumInitingCPUs = 0;
  69 tMPInfo *gMPFloatPtr = NULL;
  70 tAPIC   *gpMP_LocalAPIC = NULL;
  71 Uint8   gaAPIC_to_CPU[256] = {0};
  72 #endif
  73 tCPU    gaCPUs[MAX_CPUS];
  74 tTSS    *gTSSs = NULL;
  75 tTSS    gTSS0 = {0};
  76 // --- Error Recovery ---
  77 Uint32  gaDoubleFaultStack[1024];
  78
  79 // === CODE ===
  80 /**
  81  * \fn void ArchThreads_Init(void)
  82  * \brief Starts the process scheduler
  83  */
  84 void ArchThreads_Init(void)
  85 {
  86         Uint    pos = 0;
  87
  88         #if USE_MP
  89         tMPTable        *mptable;
  90
  91         // Mark BSP as active
  92         gaCPUs[0].State = 2;
  93
  94         // -- Initialise Multiprocessing
  95         // Find MP Floating Table
  96         // - EBDA/Last 1Kib (640KiB)
  97         for(pos = KERNEL_BASE|0x9F000; pos < (KERNEL_BASE|0xA0000); pos += 16) {
  98                 if( *(Uint*)(pos) == MPPTR_IDENT ) {
  99                         Log("Possible %p", pos);
 100                         if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 101                         gMPFloatPtr = (void*)pos;
 102                         break;
 103                 }
 104         }
 105         // - Last KiB (512KiB base mem)
 106         if(!gMPFloatPtr) {
 107                 for(pos = KERNEL_BASE|0x7F000; pos < (KERNEL_BASE|0x80000); pos += 16) {
 108                         if( *(Uint*)(pos) == MPPTR_IDENT ) {
 109                                 Log("Possible %p", pos);
 110                                 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 111                                 gMPFloatPtr = (void*)pos;
 112                                 break;
 113                         }
 114                 }
 115         }
 116         // - BIOS ROM
 117         if(!gMPFloatPtr) {
 118                 for(pos = KERNEL_BASE|0xE0000; pos < (KERNEL_BASE|0x100000); pos += 16) {
 119                         if( *(Uint*)(pos) == MPPTR_IDENT ) {
 120                                 Log("Possible %p", pos);
 121                                 if( ByteSum((void*)pos, sizeof(tMPInfo)) != 0 ) continue;
 122                                 gMPFloatPtr = (void*)pos;
 123                                 break;
 124                         }
 125                 }
 126         }
 127
 128         // If the MP Table Exists, parse it
 129         if(gMPFloatPtr)
 130         {
 131                  int    i;
 132                 tMPTable_Ent    *ents;
 133                 Log("gMPFloatPtr = %p", gMPFloatPtr);
 134                 Log("*gMPFloatPtr = {");
 135                 Log("\t.Sig = 0x%08x", gMPFloatPtr->Sig);
 136                 Log("\t.MPConfig = 0x%08x", gMPFloatPtr->MPConfig);
 137                 Log("\t.Length = 0x%02x", gMPFloatPtr->Length);
 138                 Log("\t.Version = 0x%02x", gMPFloatPtr->Version);
 139                 Log("\t.Checksum = 0x%02x", gMPFloatPtr->Checksum);
 140                 Log("\t.Features = [0x%02x,0x%02x,0x%02x,0x%02x,0x%02x]",
 141                         gMPFloatPtr->Features[0],       gMPFloatPtr->Features[1],
 142                         gMPFloatPtr->Features[2],       gMPFloatPtr->Features[3],
 143                         gMPFloatPtr->Features[4]
 144                         );
 145                 Log("}");
 146
 147                 mptable = (void*)( KERNEL_BASE|gMPFloatPtr->MPConfig );
 148                 Log("mptable = %p", mptable);
 149                 Log("*mptable = {");
 150                 Log("\t.Sig = 0x%08x", mptable->Sig);
 151                 Log("\t.BaseTableLength = 0x%04x", mptable->BaseTableLength);
 152                 Log("\t.SpecRev = 0x%02x", mptable->SpecRev);
 153                 Log("\t.Checksum = 0x%02x", mptable->Checksum);
 154                 Log("\t.OEMID = '%8c'", mptable->OemID);
 155                 Log("\t.ProductID = '%8c'", mptable->ProductID);
 156                 Log("\t.OEMTablePtr = %p'", mptable->OEMTablePtr);
 157                 Log("\t.OEMTableSize = 0x%04x", mptable->OEMTableSize);
 158                 Log("\t.EntryCount = 0x%04x", mptable->EntryCount);
 159                 Log("\t.LocalAPICMemMap = 0x%08x", mptable->LocalAPICMemMap);
 160                 Log("\t.ExtendedTableLen = 0x%04x", mptable->ExtendedTableLen);
 161                 Log("\t.ExtendedTableChecksum = 0x%02x", mptable->ExtendedTableChecksum);
 162                 Log("}");
 163
 164                 gpMP_LocalAPIC = (void*)MM_MapHWPage(mptable->LocalAPICMemMap, 1);
 165
 166                 ents = mptable->Entries;
 167                 giNumCPUs = 0;
 168
 169                 for( i = 0; i < mptable->EntryCount; i ++ )
 170                 {
 171                          int    entSize = 0;
 172                         switch( ents->Type )
 173                         {
 174                         case 0: // Processor
 175                                 entSize = 20;
 176                                 Log("%i: Processor", i);
 177                                 Log("\t.APICID = %i", ents->Proc.APICID);
 178                                 Log("\t.APICVer = 0x%02x", ents->Proc.APICVer);
 179                                 Log("\t.CPUFlags = 0x%02x", ents->Proc.CPUFlags);
 180                                 Log("\t.CPUSignature = 0x%08x", ents->Proc.CPUSignature);
 181                                 Log("\t.FeatureFlags = 0x%08x", ents->Proc.FeatureFlags);
 182
 183
 184                                 if( !(ents->Proc.CPUFlags & 1) ) {
 185                                         Log("DISABLED");
 186                                         break;
 187                                 }
 188
 189                                 // Check if there is too many processors
 190                                 if(giNumCPUs >= MAX_CPUS) {
 191                                         giNumCPUs ++;   // If `giNumCPUs` > MAX_CPUS later, it will be clipped
 192                                         break;
 193                                 }
 194
 195                                 // Initialise CPU Info
 196                                 gaAPIC_to_CPU[ents->Proc.APICID] = giNumCPUs;
 197                                 gaCPUs[giNumCPUs].APICID = ents->Proc.APICID;
 198                                 gaCPUs[giNumCPUs].State = 0;
 199                                 giNumCPUs ++;
 200
 201                                 // Send IPI
 202                                 if( !(ents->Proc.CPUFlags & 2) )
 203                                 {
 204                                         MP_StartAP( giNumCPUs-1 );
 205                                 }
 206
 207                                 break;
 208                         case 1: // Bus
 209                                 entSize = 8;
 210                                 Log("%i: Bus", i);
 211                                 Log("\t.ID = %i", ents->Bus.ID);
 212                                 Log("\t.TypeString = '%6c'", ents->Bus.TypeString);
 213                                 break;
 214                         case 2: // I/O APIC
 215                                 entSize = 8;
 216                                 Log("%i: I/O APIC", i);
 217                                 Log("\t.ID = %i", ents->IOAPIC.ID);
 218                                 Log("\t.Version = 0x%02x", ents->IOAPIC.Version);
 219                                 Log("\t.Flags = 0x%02x", ents->IOAPIC.Flags);
 220                                 Log("\t.Addr = 0x%08x", ents->IOAPIC.Addr);
 221                                 break;
 222                         case 3: // I/O Interrupt Assignment
 223                                 entSize = 8;
 224                                 Log("%i: I/O Interrupt Assignment", i);
 225                                 Log("\t.IntType = %i", ents->IOInt.IntType);
 226                                 Log("\t.Flags = 0x%04x", ents->IOInt.Flags);
 227                                 Log("\t.SourceBusID = 0x%02x", ents->IOInt.SourceBusID);
 228                                 Log("\t.SourceBusIRQ = 0x%02x", ents->IOInt.SourceBusIRQ);
 229                                 Log("\t.DestAPICID = 0x%02x", ents->IOInt.DestAPICID);
 230                                 Log("\t.DestAPICIRQ = 0x%02x", ents->IOInt.DestAPICIRQ);
 231                                 break;
 232                         case 4: // Local Interrupt Assignment
 233                                 entSize = 8;
 234                                 Log("%i: Local Interrupt Assignment", i);
 235                                 Log("\t.IntType = %i", ents->LocalInt.IntType);
 236                                 Log("\t.Flags = 0x%04x", ents->LocalInt.Flags);
 237                                 Log("\t.SourceBusID = 0x%02x", ents->LocalInt.SourceBusID);
 238                                 Log("\t.SourceBusIRQ = 0x%02x", ents->LocalInt.SourceBusIRQ);
 239                                 Log("\t.DestLocalAPICID = 0x%02x", ents->LocalInt.DestLocalAPICID);
 240                                 Log("\t.DestLocalAPICIRQ = 0x%02x", ents->LocalInt.DestLocalAPICIRQ);
 241                                 break;
 242                         default:
 243                                 Log("%i: Unknown (%i)", i, ents->Type);
 244                                 break;
 245                         }
 246                         ents = (void*)( (Uint)ents + entSize );
 247                 }
 248
 249                 if( giNumCPUs > MAX_CPUS ) {
 250                         Warning("Too many CPUs detected (%i), only using %i of them", giNumCPUs, MAX_CPUS);
 251                         giNumCPUs = MAX_CPUS;
 252                 }
 253
 254                 while( giNumInitingCPUs )
 255                         MM_FinishVirtualInit();
 256
 257                 Panic("Uh oh... MP Table Parsing is unimplemented\n");
 258         }
 259         else {
 260                 Log("No MP Table was found, assuming uniprocessor\n");
 261                 giNumCPUs = 1;
 262                 gTSSs = &gTSS0;
 263         }
 264         #else
 265         giNumCPUs = 1;
 266         gTSSs = &gTSS0;
 267         MM_FinishVirtualInit();
 268         #endif
 269
 270         #if USE_MP
 271         // Initialise Normal TSS(s)
 272         for(pos=0;pos<giNumCPUs;pos++)
 273         {
 274         #else
 275         pos = 0;
 276         #endif
 277                 gTSSs[pos].RSP0 = 0;    // Set properly by scheduler
 278                 gGDT[7+pos*2].LimitLow = sizeof(tTSS) & 0xFFFF;
 279                 gGDT[7+pos*2].BaseLow = ((Uint)(&gTSSs[pos])) & 0xFFFF;
 280                 gGDT[7+pos*2].BaseMid = ((Uint)(&gTSSs[pos])) >> 16;
 281                 gGDT[7+pos*2].BaseHi = ((Uint)(&gTSSs[pos])) >> 24;
 282                 gGDT[7+pos*2+1].DWord[0] = ((Uint)(&gTSSs[pos])) >> 32;
 283         #if USE_MP
 284         }
 285         for(pos=0;pos<giNumCPUs;pos++) {
 286         #endif
 287                 __asm__ __volatile__ ("ltr %%ax"::"a"(0x38+pos*16));
 288         #if USE_MP
 289         }
 290         #endif
 291
 292         gaCPUs[0].Current = &gThreadZero;
 293
 294         gThreadZero.MemState.CR3 = (Uint)gInitialPML4 - KERNEL_BASE;
 295
 296         // Set timer frequency
 297         outb(0x43, 0x34);       // Set Channel 0, Low/High, Rate Generator
 298         outb(0x40, TIMER_DIVISOR&0xFF); // Low Byte of Divisor
 299         outb(0x40, (TIMER_DIVISOR>>8)&0xFF);    // High Byte
 300
 301         // Create Per-Process Data Block
 302         MM_Allocate(MM_PPD_CFG);
 303
 304         // Change Stacks
 305         Proc_ChangeStack();
 306 }
 307
 308 #if USE_MP
 309 void MP_StartAP(int CPU)
 310 {
 311         Log("Starting AP %i (APIC %i)", CPU, gaCPUs[CPU].APICID);
 312         // Set location of AP startup code and mark for a warm restart
 313         *(Uint16*)(KERNEL_BASE|0x467) = (Uint)&APStartup - (KERNEL_BASE|0xFFFF0);
 314         *(Uint16*)(KERNEL_BASE|0x469) = 0xFFFF;
 315         outb(0x70, 0x0F);       outb(0x71, 0x0A);       // Warm Reset
 316         MP_SendIPI(gaCPUs[CPU].APICID, 0, 5);
 317         giNumInitingCPUs ++;
 318 }
 319
 320 void MP_SendIPI(Uint8 APICID, int Vector, int DeliveryMode)
 321 {
 322         Uint32  addr = (Uint)gpMP_LocalAPIC + 0x300;
 323         Uint32  val;
 324
 325         // High
 326         val = (Uint)APICID << 24;
 327         Log("*%p = 0x%08x", addr+0x10, val);
 328         *(Uint32*)(addr+0x10) = val;
 329         // Low (and send)
 330         val = ((DeliveryMode & 7) << 8) | (Vector & 0xFF);
 331         Log("*%p = 0x%08x", addr, val);
 332         *(Uint32*)addr = val;
 333 }
 334 #endif
 335
 336 /**
 337  * \fn void Proc_Start(void)
 338  * \brief Start process scheduler
 339  */
 340 void Proc_Start(void)
 341 {
 342         #if USE_MP
 343          int    i;
 344         #endif
 345
 346         #if USE_MP
 347         // Start APs
 348         for( i = 0; i < giNumCPUs; i ++ )
 349         {
 350                  int    tid;
 351                 if(i)   gaCPUs[i].Current = NULL;
 352
 353                 // Create Idle Task
 354                 if( (tid = Proc_Clone(0, 0)) == 0)
 355                 {
 356                         for(;;) HALT(); // Just yeilds
 357                 }
 358                 gaCPUs[i].IdleThread = Threads_GetThread(tid);
 359                 gaCPUs[i].IdleThread->ThreadName = "Idle Thread";
 360                 Threads_SetTickets( gaCPUs[i].IdleThread, 0 );  // Never called randomly
 361                 gaCPUs[i].IdleThread->Quantum = 1;      // 1 slice quantum
 362
 363
 364                 // Start the AP
 365                 if( i != giProc_BootProcessorID ) {
 366                         MP_StartAP( i );
 367                 }
 368         }
 369
 370         // BSP still should run the current task
 371         gaCPUs[0].Current = &gThreadZero;
 372
 373         // Start interrupts and wait for APs to come up
 374         Log("Waiting for APs to come up\n");
 375         __asm__ __volatile__ ("sti");
 376         while( giNumInitingCPUs )       __asm__ __volatile__ ("hlt");
 377         #else
 378         // Create Idle Task
 379         if(Proc_Clone(0, 0) == 0)
 380         {
 381                 gaCPUs[0].IdleThread = Proc_GetCurThread();
 382                 gaCPUs[0].IdleThread->ThreadName = "Idle Thread";
 383                 gaCPUs[0].IdleThread->NumTickets = 0;   // Never called randomly
 384                 gaCPUs[0].IdleThread->Quantum = 1;      // 1 slice quantum
 385                 for(;;) HALT(); // Just yeilds
 386         }
 387
 388         // Set current task
 389         gaCPUs[0].Current = &gThreadZero;
 390
 391         // Start Interrupts (and hence scheduler)
 392         __asm__ __volatile__("sti");
 393         #endif
 394         MM_FinishVirtualInit();
 395 }
 396
 397 /**
 398  * \fn tThread *Proc_GetCurThread(void)
 399  * \brief Gets the current thread
 400  */
 401 tThread *Proc_GetCurThread(void)
 402 {
 403         #if USE_MP
 404         return gaCPUs[ GetCPUNum() ].Current;
 405         #else
 406         return gaCPUs[ 0 ].Current;
 407         #endif
 408 }
 409
 410 /**
 411  * \fn void Proc_ChangeStack(void)
 412  * \brief Swaps the current stack for a new one (in the proper stack reigon)
 413  */
 414 void Proc_ChangeStack(void)
 415 {
 416         Uint    rsp, rbp;
 417         Uint    tmp_rbp, old_rsp;
 418         Uint    curBase, newBase;
 419
 420         __asm__ __volatile__ ("mov %%rsp, %0":"=r"(rsp));
 421         __asm__ __volatile__ ("mov %%rbp, %0":"=r"(rbp));
 422
 423         old_rsp = rsp;
 424
 425         // Create new KStack
 426         newBase = MM_NewKStack();
 427         // Check for errors
 428         if(newBase == 0) {
 429                 Panic("What the?? Unable to allocate space for initial kernel stack");
 430                 return;
 431         }
 432
 433         curBase = (Uint)&gInitialKernelStack;
 434
 435         Log("curBase = 0x%x, newBase = 0x%x", curBase, newBase);
 436
 437         // Get ESP as a used size
 438         rsp = curBase - rsp;
 439         Log("memcpy( %p, %p, 0x%x )", (void*)(newBase - rsp), (void*)(curBase - rsp), rsp );
 440         // Copy used stack
 441         memcpy( (void*)(newBase - rsp), (void*)(curBase - rsp), rsp );
 442         // Get ESP as an offset in the new stack
 443         rsp = newBase - rsp;
 444         // Adjust EBP
 445         rbp = newBase - (curBase - rbp);
 446
 447         Log("Update stack");
 448         // Repair EBPs & Stack Addresses
 449         // Catches arguments also, but may trash stack-address-like values
 450         for(tmp_rbp = rsp; tmp_rbp < newBase; tmp_rbp += sizeof(Uint))
 451         {
 452                 if(old_rsp < *(Uint*)tmp_rbp && *(Uint*)tmp_rbp < curBase)
 453                         *(Uint*)tmp_rbp += newBase - curBase;
 454         }
 455
 456         Log("Applying Changes");
 457         Proc_GetCurThread()->KernelStack = newBase;
 458         __asm__ __volatile__ ("mov %0, %%rsp"::"r"(rsp));
 459         __asm__ __volatile__ ("mov %0, %%rbp"::"r"(rbp));
 460 }
 461
 462 /**
 463  * \fn int Proc_Clone(Uint *Err, Uint Flags)
 464  * \brief Clone the current process
 465  */
 466 int Proc_Clone(Uint *Err, Uint Flags)
 467 {
 468         tThread *newThread;
 469         tThread *cur = Proc_GetCurThread();
 470         Uint    rip, rsp, rbp;
 471
 472         __asm__ __volatile__ ("mov %%rsp, %0": "=r"(rsp));
 473         __asm__ __volatile__ ("mov %%rbp, %0": "=r"(rbp));
 474
 475         newThread = Threads_CloneTCB(Err, Flags);
 476         if(!newThread)  return -1;
 477
 478         Log("Proc_Clone: newThread = %p", newThread);
 479
 480         // Initialise Memory Space (New Addr space or kernel stack)
 481         if(Flags & CLONE_VM) {
 482                 Log("Proc_Clone: Cloning VM");
 483                 newThread->MemState.CR3 = MM_Clone();
 484                 newThread->KernelStack = cur->KernelStack;
 485         } else {
 486                 Uint    tmp_rbp, old_rsp = rsp;
 487
 488                 // Set CR3
 489                 newThread->MemState.CR3 = cur->MemState.CR3;
 490
 491                 // Create new KStack
 492                 newThread->KernelStack = MM_NewKStack();
 493                 Log("Proc_Clone: newKStack = %p", newThread->KernelStack);
 494                 // Check for errors
 495                 if(newThread->KernelStack == 0) {
 496                         free(newThread);
 497                         return -1;
 498                 }
 499
 500                 // Get ESP as a used size
 501                 rsp = cur->KernelStack - rsp;
 502                 // Copy used stack
 503                 memcpy(
 504                         (void*)(newThread->KernelStack - rsp),
 505                         (void*)(cur->KernelStack - rsp),
 506                         rsp
 507                         );
 508                 // Get ESP as an offset in the new stack
 509                 rsp = newThread->KernelStack - rsp;
 510                 // Adjust EBP
 511                 rbp = newThread->KernelStack - (cur->KernelStack - rbp);
 512
 513                 // Repair EBPs & Stack Addresses
 514                 // Catches arguments also, but may trash stack-address-like values
 515                 for(tmp_rbp = rsp; tmp_rbp < newThread->KernelStack; tmp_rbp += sizeof(Uint))
 516                 {
 517                         if(old_rsp < *(Uint*)tmp_rbp && *(Uint*)tmp_rbp < cur->KernelStack)
 518                                 *(Uint*)tmp_rbp += newThread->KernelStack - cur->KernelStack;
 519                 }
 520         }
 521
 522         // Save core machine state
 523         newThread->SavedState.RSP = rsp;
 524         newThread->SavedState.RBP = rbp;
 525         rip = GetRIP();
 526         if(rip == SWITCH_MAGIC) {
 527                 outb(0x20, 0x20);       // ACK Timer and return as child
 528                 return 0;
 529         }
 530
 531         // Set EIP as parent
 532         newThread->SavedState.RIP = rip;
 533
 534         // Lock list and add to active
 535         Threads_AddActive(newThread);
 536
 537         return newThread->TID;
 538 }
 539
 540 /**
 541  * \fn int Proc_SpawnWorker(void)
 542  * \brief Spawns a new worker thread
 543  */
 544 int Proc_SpawnWorker(void)
 545 {
 546         tThread *new, *cur;
 547         Uint    rip, rsp, rbp;
 548
 549         cur = Proc_GetCurThread();
 550
 551         // Create new thread
 552         new = malloc( sizeof(tThread) );
 553         if(!new) {
 554                 Warning("Proc_SpawnWorker - Out of heap space!\n");
 555                 return -1;
 556         }
 557         memcpy(new, &gThreadZero, sizeof(tThread));
 558         // Set Thread ID
 559         new->TID = giNextTID++;
 560         // Create a new worker stack (in PID0's address space)
 561         // The stack is relocated by this code
 562         new->KernelStack = MM_NewWorkerStack();
 563
 564         // Get ESP and EBP based in the new stack
 565         __asm__ __volatile__ ("mov %%rsp, %0": "=r"(rsp));
 566         __asm__ __volatile__ ("mov %%rbp, %0": "=r"(rbp));
 567         rsp = new->KernelStack - (cur->KernelStack - rsp);
 568         rbp = new->KernelStack - (cur->KernelStack - rbp);
 569
 570         // Save core machine state
 571         new->SavedState.RSP = rsp;
 572         new->SavedState.RBP = rbp;
 573         rip = GetRIP();
 574         if(rip == SWITCH_MAGIC) {
 575                 outb(0x20, 0x20);       // ACK Timer and return as child
 576                 return 0;
 577         }
 578
 579         // Set EIP as parent
 580         new->SavedState.RIP = rip;
 581         // Mark as active
 582         new->Status = THREAD_STAT_ACTIVE;
 583         Threads_AddActive( new );
 584
 585         return new->TID;
 586 }
 587
 588 /**
 589  * \fn Uint Proc_MakeUserStack(void)
 590  * \brief Creates a new user stack
 591  */
 592 Uint Proc_MakeUserStack(void)
 593 {
 594          int    i;
 595         Uint    base = USER_STACK_TOP - USER_STACK_SZ;
 596
 597         // Check Prospective Space
 598         for( i = USER_STACK_SZ >> 12; i--; )
 599                 if( MM_GetPhysAddr( base + (i<<12) ) != 0 )
 600                         break;
 601
 602         if(i != -1)     return 0;
 603
 604         // Allocate Stack - Allocate incrementally to clean up MM_Dump output
 605         for( i = 0; i < USER_STACK_SZ/4069; i++ )
 606                 MM_Allocate( base + (i<<12) );
 607
 608         return base + USER_STACK_SZ;
 609 }
 610
 611
 612 /**
 613  * \fn void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
 614  * \brief Starts a user task
 615  */
 616 void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **EnvP, int DataSize)
 617 {
 618         Uint    *stack = (void*)Proc_MakeUserStack();
 619          int    i;
 620         Uint    delta;
 621         Uint16  ss, cs;
 622
 623         LOG("stack = 0x%x", stack);
 624
 625         // Copy Arguments
 626         stack = (void*)( (Uint)stack - DataSize );
 627         memcpy( stack, ArgV, DataSize );
 628
 629         // Adjust Arguments and environment
 630         delta = (Uint)stack - (Uint)ArgV;
 631         ArgV = (char**)stack;
 632         for( i = 0; ArgV[i]; i++ )      ArgV[i] += delta;
 633         i ++;
 634         EnvP = &ArgV[i];
 635         for( i = 0; EnvP[i]; i++ )      EnvP[i] += delta;
 636
 637         // User Mode Segments
 638         ss = 0x23;      cs = 0x1B;
 639
 640         // Arguments
 641         *--stack = (Uint)EnvP;
 642         *--stack = (Uint)ArgV;
 643         *--stack = (Uint)ArgC;
 644         while(*Bases)
 645                 *--stack = *Bases++;
 646         *--stack = 0;   // Return Address
 647
 648         Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
 649 }
 650
 651 void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
 652 {
 653         Uint    *stack = (void*)Stack;
 654         *--stack = SS;          //Stack Segment
 655         *--stack = Stack;       //Stack Pointer
 656         *--stack = Flags;       //EFLAGS (Resvd (0x2) and IF (0x20))
 657         *--stack = CS;          //Code Segment
 658         *--stack = IP;  //EIP
 659         //PUSHAD
 660         *--stack = 0xAAAAAAAA;  // eax
 661         *--stack = 0xCCCCCCCC;  // ecx
 662         *--stack = 0xDDDDDDDD;  // edx
 663         *--stack = 0xBBBBBBBB;  // ebx
 664         *--stack = 0xD1D1D1D1;  // edi
 665         *--stack = 0x54545454;  // rsp - NOT POPED
 666         *--stack = 0x51515151;  // esi
 667         *--stack = 0xB4B4B4B4;  // rbp
 668         //Individual PUSHs
 669         *--stack = SS;  // ds
 670
 671         __asm__ __volatile__ (
 672         "mov %%rax,%%rsp;\n\t"  // Set stack pointer
 673         "iret;\n\t" : : "a" (stack));
 674         for(;;);
 675 }
 676
 677 /**
 678  * \fn int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
 679  * \brief Demotes a process to a lower permission level
 680  * \param Err   Pointer to user's errno
 681  * \param Dest  New Permission Level
 682  * \param Regs  Pointer to user's register structure
 683  */
 684 int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
 685 {
 686          int    cpl = Regs->CS & 3;
 687         // Sanity Check
 688         if(Dest > 3 || Dest < 0) {
 689                 *Err = -EINVAL;
 690                 return -1;
 691         }
 692
 693         // Permission Check
 694         if(cpl > Dest) {
 695                 *Err = -EACCES;
 696                 return -1;
 697         }
 698
 699         // Change the Segment Registers
 700         Regs->CS = (((Dest+1)<<4) | Dest) - 8;
 701         Regs->SS = ((Dest+1)<<4) | Dest;
 702
 703         return 0;
 704 }
 705
 706 /**
 707  * \brief Calls a signal handler in user mode
 708  * \note Used for signals
 709  */
 710 void Proc_CallFaultHandler(tThread *Thread)
 711 {
 712         // Rewinds the stack and calls the user function
 713         // Never returns
 714         __asm__ __volatile__ ("mov %0, %%rbp;\n\tcall Proc_ReturnToUser" :: "r"(Thread->FaultHandler));
 715         for(;;);
 716 }
 717
 718 /**
 719  * \fn void Proc_Scheduler(int CPU)
 720  * \brief Swap current thread and clears dead threads
 721  */
 722 void Proc_Scheduler(int CPU)
 723 {
 724         Uint    rsp, rbp, rip;
 725         tThread *thread;
 726
 727         // If the spinlock is set, let it complete
 728         if(IS_LOCKED(&glThreadListLock))        return;
 729
 730         // Get current thread
 731         thread = gaCPUs[CPU].Current;
 732
 733         // Reduce remaining quantum and continue timeslice if non-zero
 734         if(thread->Remaining--) return;
 735         // Reset quantum for next call
 736         thread->Remaining = thread->Quantum;
 737
 738         // Get machine state
 739         __asm__ __volatile__ ("mov %%rsp, %0":"=r"(rsp));
 740         __asm__ __volatile__ ("mov %%rbp, %0":"=r"(rbp));
 741         rip = GetRIP();
 742         if(rip == SWITCH_MAGIC) return; // Check if a switch happened
 743
 744         // Save machine state
 745         thread->SavedState.RSP = rsp;
 746         thread->SavedState.RBP = rbp;
 747         thread->SavedState.RIP = rip;
 748
 749         // Get next thread
 750         thread = Threads_GetNextToRun(CPU, thread);
 751
 752         // Error Check
 753         if(thread == NULL) {
 754                 thread = gaCPUs[CPU].IdleThread;
 755                 Warning("Hmm... Threads_GetNextToRun returned NULL, I don't think this should happen.\n");
 756                 return;
 757         }
 758
 759         #if DEBUG_TRACE_SWITCH
 760         Log("Switching to task %i, CR3 = 0x%x, RIP = %p",
 761                 thread->TID,
 762                 thread->MemState.CR3,
 763                 thread->SavedState.RIP
 764                 );
 765         #endif
 766
 767         // Set current thread
 768         gaCPUs[CPU].Current = thread;
 769
 770         // Update Kernel Stack pointer
 771         gTSSs[CPU].RSP0 = thread->KernelStack-4;
 772
 773         // Set address space
 774         __asm__ __volatile__ ("mov %0, %%cr3"::"a"(thread->MemState.CR3));
 775
 776         // Switch threads
 777         __asm__ __volatile__ (
 778                 "mov %1, %%rsp\n\t"     // Restore RSP
 779                 "mov %2, %%rbp\n\t"     // and RBP
 780                 "jmp *%3" : :   // And return to where we saved state (Proc_Clone or Proc_Scheduler)
 781                 "a"(SWITCH_MAGIC), "b"(thread->SavedState.RSP),
 782                 "d"(thread->SavedState.RBP), "c"(thread->SavedState.RIP)
 783                 );
 784         for(;;);        // Shouldn't reach here
 785 }
 786
 787 // === EXPORTS ===
 788 EXPORT(Proc_SpawnWorker);