Cleaning up and adding page fault handler

diff --git a/Kernel/arch/x86_64/errors.c b/Kernel/arch/x86_64/errors.c
index 361ccb0..c73ac0f 100644 (file)
--- a/Kernel/arch/x86_64/errors.c
+++ b/Kernel/arch/x86_64/errors.c
@@ -5,6 +5,9 @@
 #include <acess.h>
 #include <proc.h>
 
+// === IMPORTS ===
+void   MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
+
 // === PROTOTYPES ===
 void   Error_Handler(tRegs *Regs);
 
@@ -25,6 +28,12 @@ void Error_Handler(tRegs *Regs)
 {
        Uint    cr;
        
+       if( Regs->IntNum == 14 ) {
+               __asm__ __volatile__ ("mov %%cr2, %0":"=r"(cr));
+               MM_PageFault(cr, Regs->ErrorCode, Regs);
+               return ;
+       }
+       
        Debug_KernelPanic();
        
        Log("CPU Error %x, Code: 0x%x", Regs->IntNum, Regs->ErrorCode);

diff --git a/Kernel/arch/x86_64/mm_virt.c b/Kernel/arch/x86_64/mm_virt.c
index 1993fab..f6e798c 100644 (file)
--- a/Kernel/arch/x86_64/mm_virt.c
+++ b/Kernel/arch/x86_64/mm_virt.c
@@ -5,6 +5,7 @@
  */
 #include <acess.h>
 #include <mm_virt.h>
+#include <proc.h>
 
 // === CONSTANTS ===
 #define PML4_SHIFT     39
@@ -31,17 +32,153 @@
 #define PAGEDIRPTR(idx)        PAGEDIR((MM_FRACTAL_BASE>>21)+((idx)&PDP_MASK))
 #define PAGEMAPLVL4(idx)       PAGEDIRPTR((MM_FRACTAL_BASE>>30)+((idx)&PML4_MASK))
 
+// === PROTOTYPES ===
+void   MM_InitVirt(void);
+void   MM_FinishVirtualInit(void);
+void   MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
+void   MM_DumpTables(tVAddr Start, tVAddr End);
+ int   MM_Map(tVAddr VAddr, tPAddr PAddr);
+
 // === GLOBALS ===
 
 // === CODE ===
 void MM_InitVirt(void)
 {
-       
 }
 
 void MM_FinishVirtualInit(void)
 {
+}
+
+/**
+ * \brief Called on a page fault
+ */
+void MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
+{
+       // TODO: Copy on Write
+       #if 0
+       if( gaPageDir  [Addr>>22] & PF_PRESENT
+        && gaPageTable[Addr>>12] & PF_PRESENT
+        && gaPageTable[Addr>>12] & PF_COW )
+       {
+               tPAddr  paddr;
+               if(MM_GetRefCount( gaPageTable[Addr>>12] & ~0xFFF ) == 1)
+               {
+                       gaPageTable[Addr>>12] &= ~PF_COW;
+                       gaPageTable[Addr>>12] |= PF_PRESENT|PF_WRITE;
+               }
+               else
+               {
+                       //Log("MM_PageFault: COW - MM_DuplicatePage(0x%x)", Addr);
+                       paddr = MM_DuplicatePage( Addr );
+                       MM_DerefPhys( gaPageTable[Addr>>12] & ~0xFFF );
+                       gaPageTable[Addr>>12] &= PF_USER;
+                       gaPageTable[Addr>>12] |= paddr|PF_PRESENT|PF_WRITE;
+               }
+               
+               INVLPG( Addr & ~0xFFF );
+               return;
+       }
+       #endif
+       
+       // If it was a user, tell the thread handler
+       if(ErrorCode & 4) {
+               Warning("%s %s %s memory%s",
+                       (ErrorCode&4?"User":"Kernel"),
+                       (ErrorCode&2?"write to":"read from"),
+                       (ErrorCode&1?"bad/locked":"non-present"),
+                       (ErrorCode&16?" (Instruction Fetch)":"")
+                       );
+               Warning("User Pagefault: Instruction at %04x:%08x accessed %p",
+                       Regs->CS, Regs->RIP, Addr);
+               __asm__ __volatile__ ("sti");   // Restart IRQs
+//             Threads_SegFault(Addr);
+               return ;
+       }
+       
+       // Kernel #PF
+       Debug_KernelPanic();
+       // -- Check Error Code --
+       if(ErrorCode & 8)
+               Warning("Reserved Bits Trashed!");
+       else
+       {
+               Warning("%s %s %s memory%s",
+                       (ErrorCode&4?"User":"Kernel"),
+                       (ErrorCode&2?"write to":"read from"),
+                       (ErrorCode&1?"bad/locked":"non-present"),
+                       (ErrorCode&16?" (Instruction Fetch)":"")
+                       );
+       }
+       
+       Log("Code at %p accessed %p", Regs->RIP, Addr);
+       // Print Stack Backtrace
+//     Error_Backtrace(Regs->RIP, Regs->RBP);
+       
+       MM_DumpTables(0, -1);
+}
+
+/**
+ * \brief Dumps the layout of the page tables
+ */
+void MM_DumpTables(tVAddr Start, tVAddr End)
+{
+       tVAddr  rangeStart = 0;
+       tPAddr  expected = 0;
+       tVAddr  curPos;
+       Uint    page;
+       const tPAddr    MASK = ~0xF98;  // Physical address and access bits
        
+       Start >>= 12;   End >>= 12;
+       
+       Log("Table Entries:");
+       for(page = Start, curPos = Start<<12;
+               page < (End & (((tVAddr)1 << 48)-1));
+               curPos += 0x1000, page++)
+       {
+               // End of a range
+               if(
+                       !(PAGEMAPLVL4(page>>27) & PF_PRESENT)
+               ||      !(PAGEDIRPTR(page>>18) & PF_PRESENT)
+               ||      !(PAGEDIR(page>>9) & PF_PRESENT)
+               ||  !(PAGETABLE(page) & PF_PRESENT)
+               ||  (PAGETABLE(page) & MASK) != expected)
+               {
+                       if(expected) {
+                               Log(" 0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
+                                       rangeStart, curPos - 1,
+                                       PAGETABLE(rangeStart>>12) & ~0xFFF,
+                                       (expected & ~0xFFF) - 1,
+                                       (expected & PF_PAGED ? "p" : "-"),
+                                       (expected & PF_COW ? "C" : "-"),
+                                       (expected & PF_USER ? "U" : "-"),
+                                       (expected & PF_WRITE ? "W" : "-")
+                                       );
+                               expected = 0;
+                       }
+                       if( !(PAGEMAPLVL4(page>>27) & PF_PRESENT) )     continue;
+                       if( !(PAGEDIRPTR(page>>18) & PF_PRESENT) )      continue;
+                       if( !(PAGEDIR(page>>9) & PF_PRESENT) )  continue;
+                       if( !(PAGETABLE(page) & PF_PRESENT) )   continue;
+                       
+                       expected = (PAGETABLE(page) & MASK);
+                       rangeStart = curPos;
+               }
+               if(expected)    expected += 0x1000;
+       }
+       
+       if(expected) {
+               Log("0x%08x-0x%08x => 0x%08x-0x%08x (%s%s%s%s)",
+                       rangeStart, curPos - 1,
+                       PAGETABLE(rangeStart>>12) & ~0xFFF,
+                       (expected & ~0xFFF) - 1,
+                       (expected & PF_PAGED ? "p" : "-"),
+                       (expected & PF_COW ? "C" : "-"),
+                       (expected & PF_USER ? "U" : "-"),
+                       (expected & PF_WRITE ? "W" : "-")
+                       );
+               expected = 0;
+       }
 }
 
 /**
@@ -54,11 +191,11 @@ int MM_Map(tVAddr VAddr, tPAddr PAddr)
        Log("MM_Map: (VAddr=0x%x, PAddr=0x%x)", VAddr, PAddr);
        
        // Check PML4
-       Log(" MM_Map: &PAGEMAPLVL4(%x) = %x", VAddr >> 39, &PAGEMAPLVL4(VAddr >> 39));
-       Log(" MM_Map: &PAGEDIRPTR(%x) = %x", VAddr >> 30, &PAGEDIRPTR(VAddr >> 30));
-       Log(" MM_Map: &PAGEDIR(%x) = %x", VAddr >> 21, &PAGEDIR(VAddr >> 21));
-       Log(" MM_Map: &PAGETABLE(%x) = %x", VAddr >> 12, &PAGETABLE(VAddr >> 12));
-       Log(" MM_Map: &PAGETABLE(0) = %x", &PAGETABLE(0));
+       //Log(" MM_Map: &PAGEMAPLVL4(%x) = %x", VAddr >> 39, &PAGEMAPLVL4(VAddr >> 39));
+       //Log(" MM_Map: &PAGEDIRPTR(%x) = %x", VAddr >> 30, &PAGEDIRPTR(VAddr >> 30));
+       //Log(" MM_Map: &PAGEDIR(%x) = %x", VAddr >> 21, &PAGEDIR(VAddr >> 21));
+       //Log(" MM_Map: &PAGETABLE(%x) = %x", VAddr >> 12, &PAGETABLE(VAddr >> 12));
+       //Log(" MM_Map: &PAGETABLE(0) = %x", &PAGETABLE(0));
        if( !(PAGEMAPLVL4(VAddr >> 39) & 1) )
        {
                tmp = MM_AllocPhys();