Modules/UHCI - Fixed edge case NULL dereference

[tpg/acess2.git] / Kernel / arch / x86_64 / mm_virt.c

diff --git a/Kernel/arch/x86_64/mm_virt.c b/Kernel/arch/x86_64/mm_virt.c
index 9367a4f..511803c 100644 (file)
--- a/Kernel/arch/x86_64/mm_virt.c
+++ b/Kernel/arch/x86_64/mm_virt.c
@@ -8,6 +8,7 @@
 #include <mm_virt.h>
 #include <threads_int.h>
 #include <proc.h>
+#include <hal_proc.h>
 
 // === CONSTANTS ===
 #define PHYS_BITS      52      // TODO: Move out
@@ -64,13 +65,13 @@ void        MM_InitVirt(void);
 void   MM_int_ClonePageEnt( Uint64 *Ent, void *NextLevel, tVAddr Addr, int bTable );
  int   MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs);
 void   MM_int_DumpTablesEnt(tVAddr RangeStart, size_t Length, tPAddr Expected);
-void   MM_DumpTables(tVAddr Start, tVAddr End);
+//void MM_DumpTables(tVAddr Start, tVAddr End);
  int   MM_GetPageEntryPtr(tVAddr Addr, BOOL bTemp, BOOL bAllocate, BOOL bLargePage, tPAddr **Pointer);
  int   MM_MapEx(tVAddr VAddr, tPAddr PAddr, BOOL bTemp, BOOL bLarge);
 // int MM_Map(tVAddr VAddr, tPAddr PAddr);
 void   MM_Unmap(tVAddr VAddr);
 void   MM_int_ClearTableLevel(tVAddr VAddr, int LevelBits, int MaxEnts);
-void   MM_ClearUser(void);
+//void MM_ClearUser(void);
  int   MM_GetPageEntry(tVAddr Addr, tPAddr *Phys, Uint *Flags);
 
 // === GLOBALS ===
@@ -99,6 +100,8 @@ void MM_FinishVirtualInit(void)
 void MM_int_ClonePageEnt( Uint64 *Ent, void *NextLevel, tVAddr Addr, int bTable )
 {
        tPAddr  curpage = *Ent & PADDR_MASK; 
+        int    bCopied = 0;
+       
        if( MM_GetRefCount( curpage ) <= 0 ) {
                Log_KernelPanic("MMVirt", "Page %P still marked COW, but unreferenced", curpage);
        }
@@ -106,7 +109,7 @@ void MM_int_ClonePageEnt( Uint64 *Ent, void *NextLevel, tVAddr Addr, int bTable
        {
                *Ent &= ~PF_COW;
                *Ent |= PF_PRESENT|PF_WRITE;
-//             Log_Debug("MMVirt", "COW ent at %p (%p) only %P", Ent, NextLevel, curpage);
+               Log_Debug("MMVirt", "COW ent at %p (%p) only %P", Ent, NextLevel, curpage);
        }
        else
        {
@@ -124,23 +127,28 @@ void MM_int_ClonePageEnt( Uint64 *Ent, void *NextLevel, tVAddr Addr, int bTable
                memcpy( tmp, NextLevel, 0x1000 );
                MM_FreeTemp( (tVAddr)tmp );
                
-//             Log_Debug("MMVirt", "COW ent at %p (%p) from %P to %P", Ent, NextLevel, curpage, paddr);
+               Log_Debug("MMVirt", "COW ent at %p (%p) from %P to %P", Ent, NextLevel, curpage, paddr);
 
                MM_DerefPhys( curpage );
                *Ent &= PF_USER;
                *Ent |= paddr|PF_PRESENT|PF_WRITE;
+               
+               bCopied = 1;
        }
        INVLPG( (tVAddr)NextLevel );
        
-       // Mark COW on pages
+       // Mark COW on contents if it's a PDPT, Dir or Table
        if(bTable) 
        {
                Uint64  *dp = NextLevel;
                 int    i;
                for( i = 0; i < 512; i ++ )
                {
-                       if( !(dp[i] & PF_PRESENT) )     continue;
-                       MM_RefPhys( dp[i] & PADDR_MASK );
+                       if( !(dp[i] & PF_PRESENT) )
+                               continue;
+                       
+                       if( bCopied )
+                               MM_RefPhys( dp[i] & PADDR_MASK );
                        if( dp[i] & PF_WRITE ) {
                                dp[i] &= ~PF_WRITE;
                                dp[i] |= PF_COW;
@@ -154,6 +162,25 @@ void MM_int_ClonePageEnt( Uint64 *Ent, void *NextLevel, tVAddr Addr, int bTable
  */
 int MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
 {
+//     Log_Debug("MMVirt", "Addr = %p, ErrorCode = %x", Addr, ErrorCode);
+
+       // Catch reserved bits first
+       if( ErrorCode & 0x8 )
+       {
+               Log_Warning("MMVirt", "Reserved bits trashed!");
+               Log_Warning("MMVirt", "PML4 Ent   = %P", PAGEMAPLVL4(Addr>>39));
+               if( !(PAGEMAPLVL4(Addr>>39) & PF_PRESENT) )     goto print_done;
+               Log_Warning("MMVirt", "PDP Ent    = %P", PAGEDIRPTR(Addr>>30));
+               if( !(PAGEDIRPTR(Addr>>30) & PF_PRESENT) )      goto print_done;
+               Log_Warning("MMVirt", "PDir Ent   = %P", PAGEDIR(Addr>>21));
+               if( !(PAGEDIR(Addr>>21) & PF_PRESENT) ) goto print_done;
+               Log_Warning("MMVirt", "PTable Ent = %P", PAGETABLE(Addr>>12));
+               if( !(PAGETABLE(Addr>>12) & PF_PRESENT) )       goto print_done;
+       print_done:
+               
+               for(;;);
+       }
+
        // TODO: Implement Copy-on-Write
        #if 1
        if( PAGEMAPLVL4(Addr>>39) & PF_PRESENT
@@ -202,6 +229,7 @@ int MM_PageFault(tVAddr Addr, Uint ErrorCode, tRegs *Regs)
                Warning("User Pagefault: Instruction at %04x:%p accessed %p",
                        Regs->CS, Regs->RIP, Addr);
                __asm__ __volatile__ ("sti");   // Restart IRQs
+               Error_Backtrace(Regs->RIP, Regs->RBP);
                Threads_SegFault(Addr);
                return 0;
        }
@@ -649,6 +677,58 @@ Uint MM_GetFlags(tVAddr VAddr)
        return ret;
 }
 
+/**
+ * \brief Check if the provided buffer is valid
+ * \return Boolean valid
+ */
+int MM_IsValidBuffer(tVAddr Addr, size_t Size)
+{
+        int    bIsUser;
+       Uint64  pml4, pdp, dir, tab;
+
+       Size += Addr & (PAGE_SIZE-1);
+       Addr &= ~(PAGE_SIZE-1);
+       Addr &= ((1UL << 48)-1);        // Clap to address space
+
+       pml4 = Addr >> 39;
+       pdp = Addr >> 30;
+       dir = Addr >> 21;
+       tab = Addr >> 12;
+
+       if( !(PAGEMAPLVL4(pml4) & 1) )  return 0;
+       if( !(PAGEDIRPTR(pdp) & 1) )    return 0;
+       if( !(PAGEDIR(dir) & 1) )       return 0;
+       if( !(PAGETABLE(tab) & 1) )     return 0;
+       
+       bIsUser = !!(PAGETABLE(tab) & PF_USER);
+
+       while( Size >= PAGE_SIZE )
+       {
+               if( (tab & 511) == 0 )
+               {
+                       dir ++;
+                       if( ((dir >> 9) & 511) == 0 )
+                       {
+                               pdp ++;
+                               if( ((pdp >> 18) & 511) == 0 )
+                               {
+                                       pml4 ++;
+                                       if( !(PAGEMAPLVL4(pml4) & 1) )  return 0;
+                               }
+                               if( !(PAGEDIRPTR(pdp) & 1) )    return 0;
+                       }
+                       if( !(PAGEDIR(dir) & 1) )       return 0;
+               }
+               
+               if( !(PAGETABLE(tab) & 1) )   return 0;
+               if( bIsUser && !(PAGETABLE(tab) & PF_USER) )    return 0;
+
+               tab ++;
+               Size -= PAGE_SIZE;
+       }
+       return 1;
+}
+
 // --- Hardware Mappings ---
 /**
  * \brief Map a range of hardware pages
@@ -814,11 +894,11 @@ tPAddr MM_Clone(void)
        {
                // Skip addresses:
                // 320 0xFFFFA....      - Kernel Stacks
-               if( i == 320 )  continue;
+               if( i == MM_KSTACK_BASE>>39 )   continue;
                // 509 0xFFFFFE0..      - Fractal mapping
-               if( i == 508 )  continue;
+               if( i == MM_FRACTAL_BASE>>39 )  continue;
                // 510 0xFFFFFE8..      - Temp fractal mapping
-               if( i == 509 )  continue;
+               if( i == MM_TMPFRAC_BASE>>39 )  continue;
                
                TMPMAPLVL4(i) = PAGEMAPLVL4(i);
                if( TMPMAPLVL4(i) & 1 )