From: John Hodge <tpg@mutabah.net>
Date: Sat, 29 Oct 2011 01:23:24 +0000 (+0800)
Subject: Kernel/x86_64 - Fixed recursive page fault, wasn't enabling the NX bit
X-Git-Tag: rel0.14~173
X-Git-Url: https://git.ucc.asn.au/?a=commitdiff_plain;h=4fc7ede122603881c8532ddda13dbc5dad7064e6;p=tpg%2Facess2.git

Kernel/x86_64 - Fixed recursive page fault, wasn't enabling the NX bit
---

diff --git a/Kernel/arch/x86_64/desctab.asm b/Kernel/arch/x86_64/desctab.asm
index 2ad44a0c..6e8aa639 100644
--- a/Kernel/arch/x86_64/desctab.asm
+++ b/Kernel/arch/x86_64/desctab.asm
@@ -104,12 +104,6 @@ Desctab_Init:
 	; Start interrupts
 	sti
 
-	; Initialise System Calls (SYSCALL/SYSRET)
-	; Set IA32_EFER.SCE
-	mov ecx, 0xC0000080
-	rdmsr
-	or eax, 1
-	wrmsr
 	; Set IA32_LSTAR (RIP of handler)
 	mov ecx, 0xC0000082	; IA32_LSTAR
 	mov eax, SyscallStub - 0xFFFFFFFF00000000
diff --git a/Kernel/arch/x86_64/mm_virt.c b/Kernel/arch/x86_64/mm_virt.c
index c04fcf3a..c7b7a224 100644
--- a/Kernel/arch/x86_64/mm_virt.c
+++ b/Kernel/arch/x86_64/mm_virt.c
@@ -154,6 +154,25 @@ 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
diff --git a/Kernel/arch/x86_64/start32.asm b/Kernel/arch/x86_64/start32.asm
index d38c993e..6b4f9403 100644
--- a/Kernel/arch/x86_64/start32.asm
+++ b/Kernel/arch/x86_64/start32.asm
@@ -58,6 +58,13 @@ start:
 	or eax, 0x80|0x20|0x10
 	mov cr4, eax
 
+	; Initialise System Calls (SYSCALL/SYSRET)
+	; Set IA32_EFER.(NXE|SCE)
+	mov ecx, 0xC0000080
+	rdmsr
+	or eax, (1 << 11)|(1 << 0)	; NXE, SCE
+	wrmsr
+
 	; Load PDP4
 	mov eax, gInitialPML4 - KERNEL_BASE
 	mov cr3, eax