Kernel/arch/armv7/proc.c

   1 /*
   2  * Acess2
   3  * - By John Hodge (thePowersGang)
   4  *
   5  * arch/arm7/proc.c
   6  * - ARM7 Process Switching
   7  */
   8 #include <acess.h>
   9 #include <threads_int.h>
  10 #include <hal_proc.h>
  11
  12 // === IMPORTS ===
  13 extern tThread  gThreadZero;
  14 extern void     SwitchTask(Uint32 NewSP, Uint32 *OldSP, Uint32 NewIP, Uint32 *OldIP, Uint32 MemPtr);
  15 extern void     KernelThreadHeader(void);       // Actually takes args on stack
  16 extern void     Proc_int_DropToUser(Uint32 IP, Uint32 SP) NORETURN;
  17 extern Uint32   Proc_int_SwapUserSP(Uint32 NewSP);
  18 extern Uint32   Proc_CloneInt(Uint32 *SP, Uint32 *MemPtr);
  19 extern tVAddr   MM_NewKStack(int bGlobal);      // TODO: Move out into a header
  20 extern tVAddr   MM_NewUserStack(void);
  21 extern char     kernel_table0[];
  22
  23 // === PROTOTYPES ===
  24 void    Proc_IdleThread(void *unused);
  25
  26 // === GLOBALS ===
  27 tThread *gpCurrentThread = &gThreadZero;
  28 tThread *gpIdleThread = NULL;
  29
  30 // === CODE ===
  31 void ArchThreads_Init(void)
  32 {
  33         gThreadZero.MemState.Base = (tPAddr)&kernel_table0 - KERNEL_BASE;
  34 }
  35
  36 void Proc_IdleThread(void *unused)
  37 {
  38         Threads_SetPriority(gpIdleThread, -1);
  39         for(;;) {
  40                 Proc_Reschedule();
  41                 __asm__ __volatile__ ("wfi");
  42         }
  43 }
  44
  45 void Proc_Start(void)
  46 {
  47         tTID    tid;
  48
  49         tid = Proc_NewKThread( Proc_IdleThread, NULL );
  50         gpIdleThread = Threads_GetThread(tid);
  51         gpIdleThread->ThreadName = (char*)"Idle Thread";
  52 }
  53
  54 int GetCPUNum(void)
  55 {
  56         return 0;
  57 }
  58
  59 tThread *Proc_GetCurThread(void)
  60 {
  61         return gpCurrentThread;
  62 }
  63
  64 void Proc_StartUser(Uint Entrypoint, Uint Base, int ArgC, char **ArgV, int DataSize)
  65 {
  66         Uint32  *usr_sp;
  67          int    i;
  68         char    **envp;
  69         tVAddr  delta;
  70
  71         Log_Debug("Proc", "Proc_StartUser: (Entrypoint=%p, Base=%p, ArgC=%i, ArgV=%p, DataSize=0x%x)",
  72                 Entrypoint, Base, ArgC, ArgV, DataSize);
  73
  74         // Write data to the user's stack
  75         usr_sp = (void*)MM_NewUserStack();
  76         usr_sp -= (DataSize+3)/4;
  77         memcpy(usr_sp, ArgV, DataSize);
  78         free(ArgV);
  79
  80         // Adjust user's copy of the arguments
  81         delta = (tVAddr)usr_sp -  (tVAddr)ArgV;
  82         Log("delta = %x", delta);
  83         ArgV = (void*)usr_sp;
  84         for(i = 0; ArgV[i]; i ++)       ArgV[i] += delta;
  85         envp = &ArgV[i+1];
  86         for(i = 0; envp[i]; i ++)       envp[i] += delta;
  87         Log("envp = %p", envp);
  88
  89         *--usr_sp = (Uint32)envp;
  90         *--usr_sp = (Uint32)ArgV;
  91         *--usr_sp = (Uint32)ArgC;
  92         *--usr_sp = Base;
  93
  94         // Drop to user code
  95         Log_Debug("Proc", "Proc_int_DropToUser(%p, %p)", Entrypoint, usr_sp);
  96
  97         // Needed to get around relocation truncation
  98         {
  99                 void    (*drop)(Uint32, Uint32) NORETURN = Proc_int_DropToUser;
 100                 drop(Entrypoint, (Uint32)usr_sp);
 101         }
 102 }
 103
 104 tTID Proc_Clone(Uint Flags)
 105 {
 106         tThread *new;
 107         Uint32  pc, sp, mem;
 108
 109         new = Threads_CloneTCB(Flags);
 110         if(!new)        return -1;
 111
 112         // Actual clone magic
 113         pc = Proc_CloneInt(&sp, &mem);
 114         if(pc == 0) {
 115                 Log("Proc_Clone: In child");
 116                 return 0;
 117         }
 118
 119         new->SavedState.IP = pc;
 120         new->SavedState.SP = sp;
 121         new->SavedState.UserSP = Proc_int_SwapUserSP(0);
 122         new->SavedState.UserIP = Proc_GetCurThread()->SavedState.UserIP;
 123         new->MemState.Base = mem;
 124
 125         Threads_AddActive(new);
 126
 127         return new->TID;
 128 }
 129
 130 tTID Proc_SpawnWorker( void (*Fnc)(void*), void *Ptr )
 131 {
 132         tThread *new;
 133         Uint32  sp;
 134
 135         new = Threads_CloneThreadZero();
 136         if(!new)        return -1;
 137         if(new->ThreadName)     free(new->ThreadName);
 138         new->ThreadName = NULL;
 139
 140         new->KernelStack = MM_NewKStack(1);
 141         if(!new->KernelStack) {
 142                 // TODO: Delete thread
 143                 Log_Error("Proc", "Unable to allocate kernel stack");
 144                 return -1;
 145         }
 146
 147         sp = new->KernelStack;
 148
 149         *(Uint32*)(sp -= 4) = (Uint)Ptr;
 150         *(Uint32*)(sp -= 4) = (Uint)Fnc;
 151         *(Uint32*)(sp -= 4) = (Uint)new;
 152
 153         new->SavedState.SP = sp;
 154         new->SavedState.IP = (Uint)KernelThreadHeader;
 155
 156         Threads_AddActive(new);
 157
 158         return new->TID;
 159 }
 160
 161 tTID Proc_NewKThread( void (*Fnc)(void*), void *Ptr )
 162 {
 163         tThread *new;
 164         Uint32  sp;
 165
 166         new = Threads_CloneTCB(0);
 167         if(!new)        return -1;
 168         free(new->ThreadName);
 169         new->ThreadName = NULL;
 170
 171         // TODO: Non-shared stack
 172         new->KernelStack = MM_NewKStack(1);
 173         if(!new->KernelStack) {
 174                 // TODO: Delete thread
 175                 Log_Error("Proc", "Unable to allocate kernel stack");
 176                 return -1;
 177         }
 178
 179         sp = new->KernelStack;
 180
 181         *(Uint32*)(sp -= 4) = (Uint)Ptr;
 182         *(Uint32*)(sp -= 4) = (Uint)Fnc;
 183         *(Uint32*)(sp -= 4) = (Uint)new;
 184
 185         new->SavedState.SP = sp;
 186         new->SavedState.IP = (Uint)KernelThreadHeader;
 187
 188         Threads_AddActive(new);
 189
 190         return new->TID;
 191 }
 192
 193 void Proc_CallFaultHandler(tThread *Thread)
 194 {
 195
 196 }
 197
 198 void Proc_Reschedule(void)
 199 {
 200         tThread *cur, *next;
 201
 202         cur = gpCurrentThread;
 203
 204         next = Threads_GetNextToRun(0, cur);
 205         if(!next)       next = gpIdleThread;
 206         if(!next || next == cur)        return;
 207
 208         Log("Switching to %p (%i %s) IP=%p SP=%p TTBR0=%p UsrSP=%p",
 209                 next, next->TID, next->ThreadName,
 210                 next->SavedState.IP, next->SavedState.SP, next->MemState.Base,
 211                 next->SavedState.UserSP
 212                 );
 213         Log("Requested by %p", __builtin_return_address(0));
 214
 215         gpCurrentThread = next;
 216
 217         cur->SavedState.UserSP = Proc_int_SwapUserSP( next->SavedState.UserSP );
 218
 219         SwitchTask(
 220                 next->SavedState.SP, &cur->SavedState.SP,
 221                 next->SavedState.IP, &cur->SavedState.IP,
 222                 next->MemState.Base
 223                 );
 224
 225 }
 226
 227 void Proc_DumpThreadCPUState(tThread *Thread)
 228 {
 229
 230 }
 231