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>

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>
Andi Kleen · Andi Kleen
1 parent ad5fa91399
Showing 2 changed files with 17 additions and 4 deletions Side-by-side Diff
include/linux/mm.h
mm/memory.c
@@ -685,11 +685,12 @@
 #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.
@@ -1319,7 +1319,8 @@
 				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 @@
 		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 @@
 		/* 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);
...	...	@@ -685,11 +685,12 @@
685	685	#define VM_FAULT_SIGBUS 0x0002
686	686	#define VM_FAULT_MAJOR 0x0004
687	687	#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */
	688	+#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned page */
688	689
689	690	#define VM_FAULT_NOPAGE 0x0100 /* ->fault installed the pte, not return page */
690	691	#define VM_FAULT_LOCKED 0x0200 /* ->fault locked the returned page */
691	692
692		-#define VM_FAULT_ERROR (VM_FAULT_OOM \| VM_FAULT_SIGBUS)
	693	+#define VM_FAULT_ERROR (VM_FAULT_OOM \| VM_FAULT_SIGBUS \| VM_FAULT_HWPOISON)
693	694
694	695	/*
695	696	* Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
...	...	@@ -1319,7 +1319,8 @@
1319	1319	if (ret & VM_FAULT_ERROR) {
1320	1320	if (ret & VM_FAULT_OOM)
1321	1321	return i ? i : -ENOMEM;
1322		- else if (ret & VM_FAULT_SIGBUS)
	1322	+ if (ret &
	1323	+ (VM_FAULT_HWPOISON\|VM_FAULT_SIGBUS))
1323	1324	return i ? i : -EFAULT;
1324	1325	BUG();
1325	1326	}
...	...	@@ -2511,8 +2512,15 @@
2511	2512	goto out;
2512	2513
2513	2514	entry = pte_to_swp_entry(orig_pte);
2514		- if (is_migration_entry(entry)) {
2515		- migration_entry_wait(mm, pmd, address);
	2515	+ if (unlikely(non_swap_entry(entry))) {
	2516	+ if (is_migration_entry(entry)) {
	2517	+ migration_entry_wait(mm, pmd, address);
	2518	+ } else if (is_hwpoison_entry(entry)) {
	2519	+ ret = VM_FAULT_HWPOISON;
	2520	+ } else {
	2521	+ print_bad_pte(vma, address, orig_pte, NULL);
	2522	+ ret = VM_FAULT_OOM;
	2523	+ }
2516	2524	goto out;
2517	2525	}
2518	2526	delayacct_set_flag(DELAYACCT_PF_SWAPIN);
...	...	@@ -2536,6 +2544,10 @@
2536	2544	/* Had to read the page from swap area: Major fault */
2537	2545	ret = VM_FAULT_MAJOR;
2538	2546	count_vm_event(PGMAJFAULT);
	2547	+ } else if (PageHWPoison(page)) {
	2548	+ ret = VM_FAULT_HWPOISON;
	2549	+ delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
	2550	+ goto out;
2539	2551	}
2540	2552
2541	2553	lock_page(page);