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>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9a72cc7..082b68c 100644 (file)
--- 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.

diff --git a/mm/memory.c b/mm/memory.c
index aede2ce..02bae2d 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1319,7 +1319,8 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                if (ret & VM_FAULT_ERROR) {
                                        if (ret & VM_FAULT_OOM)
                                                return i ? i : -ENOMEM;
-                                       else if (ret & VM_FAULT_SIGBUS)
+                                       if (ret &
+                                           (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
                                                return i ? i : -EFAULT;
                                        BUG();
                                }
@@ -2511,8 +2512,15 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
                goto out;
 
        entry = pte_to_swp_entry(orig_pte);
-       if (is_migration_entry(entry)) {
-               migration_entry_wait(mm, pmd, address);
+       if (unlikely(non_swap_entry(entry))) {
+               if (is_migration_entry(entry)) {
+                       migration_entry_wait(mm, pmd, address);
+               } else if (is_hwpoison_entry(entry)) {
+                       ret = VM_FAULT_HWPOISON;
+               } else {
+                       print_bad_pte(vma, address, orig_pte, NULL);
+                       ret = VM_FAULT_OOM;
+               }
                goto out;
        }
        delayacct_set_flag(DELAYACCT_PF_SWAPIN);
@@ -2536,6 +2544,10 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
                /* Had to read the page from swap area: Major fault */
                ret = VM_FAULT_MAJOR;
                count_vm_event(PGMAJFAULT);
+       } else if (PageHWPoison(page)) {
+               ret = VM_FAULT_HWPOISON;
+               delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
+               goto out;
        }
 
        lock_page(page);