kmemcheck: use kmemcheck_pte_lookup() instead of open-coding it

Lets use kmemcheck_pte_lookup() in kmemcheck_fault() instead of
open-coding it there.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>

arch/x86/mm/kmemcheck/kmemcheck.c

diff --git a/arch/x86/mm/kmemcheck/kmemcheck.c b/arch/x86/mm/kmemcheck/kmemcheck.c
index a644f24..6931e51 100644
--- a/arch/x86/mm/kmemcheck/kmemcheck.c
+++ b/arch/x86/mm/kmemcheck/kmemcheck.c
@@ -611,7 +611,6 @@
 	unsigned long error_code)
 {
 	pte_t *pte;
-	unsigned int level;
 
 	/*
 	 * XXX: Is it safe to assume that memory accesses from virtual 86
@@ -624,13 +623,9 @@
 	if (regs->cs != __KERNEL_CS)
 		return false;
 
-	pte = lookup_address(address, &level);
+	pte = kmemcheck_pte_lookup(address);
 	if (!pte)
 		return false;
-	if (level != PG_LEVEL_4K)
-		return false;
-	if (!pte_hidden(*pte))
-		return false;
 
 	if (error_code & 2)
 		kmemcheck_access(regs, address, KMEMCHECK_WRITE);