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Commit d1737fdb authored by Andi Kleen's avatar Andi Kleen Committed by Andi Kleen
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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: default avatarAndi Kleen <ak@linux.intel.com>
parent ad5fa913

include/linux/mm.h

+2 −1
Original line number Diff line number Diff line
@@ -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.

mm/memory.c

+15 −3
Original line number Diff line number Diff line
@@ -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 (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);