From 44e5e7e0533ba2544f2d37f8e051a0422966bd9b Mon Sep 17 00:00:00 2001 From: Tim Harris Date: Mon, 7 Feb 2011 15:18:52 -0800 Subject: X86: Obey the wp bit of CR0. If cr0.wp ("write protect" bit) is clear then do not generate page faults when writing to write-protected pages in kernel mode. --- src/arch/x86/tlb.cc | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'src') diff --git a/src/arch/x86/tlb.cc b/src/arch/x86/tlb.cc index a02c5e6a3..7b7af3288 100644 --- a/src/arch/x86/tlb.cc +++ b/src/arch/x86/tlb.cc @@ -634,14 +634,15 @@ TLB::translate(RequestPtr req, ThreadContext *tc, Translation *translation, // Do paging protection checks. bool inUser = (m5Reg.cpl == 3 && !(flags & (CPL0FlagBit << FlagShift))); - if ((inUser && !entry->user) || - (mode == Write && !entry->writable)) { + CR0 cr0 = tc->readMiscRegNoEffect(MISCREG_CR0); + bool badWrite = (!entry->writable && (inUser || cr0.wp)); + if ((inUser && !entry->user) || (mode == Write && badWrite)) { // The page must have been present to get into the TLB in // the first place. We'll assume the reserved bits are // fine even though we're not checking them. return new PageFault(vaddr, true, mode, inUser, false); } - if (storeCheck && !entry->writable) { + if (storeCheck && badWrite) { // This would fault if this were a write, so return a page // fault that reflects that happening. return new PageFault(vaddr, true, Write, inUser, false); -- cgit v1.2.3