HWPOISON: Add basic support for poisoned pages in fault handler v3

- Add a new VM_FAULT_HWPOISON error code to handle_mm_fault. Right now
architectures have to explicitely enable poison page support, so
this is forward compatible to all architectures. They only need
to add it when they enable poison page support.
- Add poison page handling in swap in fault code

v2: Add missing delayacct_clear_flag (Hidehiro Kawai)
v3: Really use delayacct_clear_flag (Hidehiro Kawai)

Signed-off-by: Andi Kleen <ak@linux.intel.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9a72cc78e6b8..082b68cb5ffe 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -685,11 +685,12 @@ static inline int page_mapped(struct page *page)
 #define VM_FAULT_SIGBUS 0x0002
 #define VM_FAULT_MAJOR  0x0004
 #define VM_FAULT_WRITE  0x0008  /* Special case for get_user_pages */
+#define VM_FAULT_HWPOISON 0x0010        /* Hit poisoned page */
 
 #define VM_FAULT_NOPAGE 0x0100  /* ->fault installed the pte, not return page */
 #define VM_FAULT_LOCKED 0x0200  /* ->fault locked the returned page */
 
-#define VM_FAULT_ERROR  (VM_FAULT_OOM | VM_FAULT_SIGBUS)
+#define VM_FAULT_ERROR  (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_HWPOISON)
 
 /*
  * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.