Revert "x86 PAT: remove CPA WARN_ON for zero pte"
This reverts commit 58dab916dfb57328d50deb0aa9b3fc92efa248ff, which
makes my Nehalem come to a nasty crawling almost-halt. It looks like it
turns off caching of regular kernel RAM, with the understandable
slowdown of a few orders of magnitude as a result.
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 4cf30de..e89d248 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -555,12 +555,10 @@
if (!pte_val(old_pte)) {
if (!primary)
return 0;
-
- /*
- * Special error value returned, indicating that the mapping
- * did not exist at this address.
- */
- return -EFAULT;
+ WARN(1, KERN_WARNING "CPA: called for zero pte. "
+ "vaddr = %lx cpa->vaddr = %lx\n", address,
+ *cpa->vaddr);
+ return -EINVAL;
}
if (level == PG_LEVEL_4K) {