Fixes to error handling and User text mappings

[tpg/acess2.git] / Kernel / arch / x86 / proc.c

diff --git a/Kernel/arch/x86/proc.c b/Kernel/arch/x86/proc.c
index a66a540..e988416 100644 (file)
--- a/Kernel/arch/x86/proc.c
+++ b/Kernel/arch/x86/proc.c
@@ -4,6 +4,7 @@
  */
 #include <acess.h>
 #include <proc.h>
+#include <desctab.h>
 #include <mm_virt.h>
 #include <errno.h>
 #if USE_MP
@@ -15,10 +16,12 @@
 
 // === CONSTANTS ===
 #define        SWITCH_MAGIC    0xFFFACE55      // There is no code in this area
+// Base is 1193182
 #define TIMER_DIVISOR  11931   //~100Hz
 
 // === IMPORTS ===
 extern tGDT    gGDT[];
+extern tIDT    gIDT[];
 extern void APStartup();       // 16-bit AP startup code
 extern Uint    GetEIP();       // start.asm
 extern Uint32  gaInitPageDir[1024];    // start.asm
@@ -35,7 +38,8 @@ extern tThread        *gDeleteThreads;
 extern tThread *Threads_GetNextToRun(int CPU);
 extern void    Threads_Dump();
 extern tThread *Threads_CloneTCB(Uint *Err, Uint Flags);
-extern void    Isr7();
+extern void    Isr8(); // Double Fault
+extern void    Proc_AlterUserReturnAddr();
 
 // === PROTOTYPES ===
 void   ArchThreads_Init();
@@ -47,6 +51,8 @@ void  Proc_Start();
 tThread        *Proc_GetCurThread();
 void   Proc_ChangeStack();
  int   Proc_Clone(Uint *Err, Uint Flags);
+void   Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP);
+void   Proc_CallFaultHandler(tThread *Thread);
 void   Proc_Scheduler();
 
 // === GLOBALS ===
@@ -70,7 +76,12 @@ char gaDoubleFaultStack[1024];
 tTSS   gDoubleFault_TSS = {
        .ESP0 = (Uint)&gaDoubleFaultStack[1023],
        .SS0 = 0x10,
-       .EIP = (Uint)Isr7
+       .CR3 = (Uint)gaInitPageDir - KERNEL_BASE,
+       .EIP = (Uint)Isr8,
+       .ESP = (Uint)&gaDoubleFaultStack[1023],
+       .CS = 0x08,     .SS = 0x10,
+       .DS = 0x10,     .ES = 0x10,
+       .FS = 0x10,     .GS = 0x10,
 };
 
 // === CODE ===
@@ -275,6 +286,17 @@ void ArchThreads_Init()
        gGDT[5].BaseMid = (Uint)&gDoubleFault_TSS >> 16;
        gGDT[5].BaseHi = (Uint)&gDoubleFault_TSS >> 24;
        
+       Log_Debug("Proc", "gIDT[8] = {OffsetLo:%04x, CS:%04x, Flags:%04x, OffsetHi:%04x}", 
+               gIDT[8].OffsetLo, gIDT[8].CS, gIDT[8].Flags, gIDT[8].OffsetHi);
+       gIDT[8].OffsetLo = 0;
+       gIDT[8].CS = 5<<3;
+       gIDT[8].Flags = 0x8500;
+       gIDT[8].OffsetHi = 0;
+       Log_Debug("Proc", "gIDT[8] = {OffsetLo:%04x, CS:%04x, Flags:%04x, OffsetHi:%04x}", 
+               gIDT[8].OffsetLo, gIDT[8].CS, gIDT[8].Flags, gIDT[8].OffsetHi);
+       
+       //__asm__ __volatile__ ("xchg %bx, %bx");
+       
        #if USE_MP
        // Initialise Normal TSS(s)
        for(pos=0;pos<giNumCPUs;pos++)
@@ -601,13 +623,18 @@ void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **
        while(*Bases)
                *--stack = *Bases++;
        *--stack = 0;   // Return Address
-       delta = (Uint)stack;    // Reuse delta to save SP
        
-       *--stack = ss;          //Stack Segment
-       *--stack = delta;       //Stack Pointer
-       *--stack = 0x0202;      //EFLAGS (Resvd (0x2) and IF (0x20))
-       *--stack = cs;          //Code Segment
-       *--stack = Entrypoint;  //EIP
+       Proc_StartProcess(ss, (Uint)stack, 0x202, cs, Entrypoint);
+}
+
+void Proc_StartProcess(Uint16 SS, Uint Stack, Uint Flags, Uint16 CS, Uint IP)
+{
+       Uint    *stack = (void*)Stack;
+       *--stack = SS;          //Stack Segment
+       *--stack = Stack;       //Stack Pointer
+       *--stack = Flags;       //EFLAGS (Resvd (0x2) and IF (0x20))
+       *--stack = CS;          //Code Segment
+       *--stack = IP;  //EIP
        //PUSHAD
        *--stack = 0xAAAAAAAA;  // eax
        *--stack = 0xCCCCCCCC;  // ecx
@@ -618,10 +645,10 @@ void Proc_StartUser(Uint Entrypoint, Uint *Bases, int ArgC, char **ArgV, char **
        *--stack = 0x51515151;  // esi
        *--stack = 0xB4B4B4B4;  // ebp
        //Individual PUSHs
-       *--stack = ss;  // ds
-       *--stack = ss;  // es
-       *--stack = ss;  // fs
-       *--stack = ss;  // gs
+       *--stack = SS;  // ds
+       *--stack = SS;  // es
+       *--stack = SS;  // fs
+       *--stack = SS;  // gs
        
        __asm__ __volatile__ (
        "mov %%eax,%%esp;\n\t"  // Set stack pointer
@@ -668,6 +695,18 @@ int Proc_Demote(Uint *Err, int Dest, tRegs *Regs)
        return 0;
 }
 
+/**
+ * \brief Calls a signal handler in user mode
+ * \note Used for signals
+ */
+void Proc_CallFaultHandler(tThread *Thread)
+{
+       // Rewinds the stack and calls the user function
+       // Never returns
+       __asm__ __volatile__ ("mov %0, %%ebp;\n\tcall Proc_AlterUserReturnAddr" :: "r"(Thread->FaultHandler));
+       for(;;);
+}
+
 /**
  * \fn void Proc_Scheduler(int CPU)
  * \brief Swap current thread and clears dead threads
@@ -754,6 +793,14 @@ void Proc_Scheduler(int CPU)
        #else
                __asm__ __volatile__ ("mov %0, %%cr3"::"a"(thread->MemState.CR3));
        #endif
+       
+       #if 0
+       if(thread->SavedState.ESP > 0xC0000000
+       && thread->SavedState.ESP < thread->KernelStack-0x2000) {
+               Log_Warning("Proc", "Possible bad ESP %p (PID %i)", thread->SavedState.ESP);
+       }
+       #endif
+       
        // Switch threads
        __asm__ __volatile__ (
                "mov %1, %%esp\n\t"     // Restore ESP