[PATCH] pagemap: expose hwpoison entry

[Naoya Horiguchi]

not-signed-off-by-yet: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
---
 fs/proc/task_mmu.c      |  6 ++++++
 include/linux/swapops.h | 12 ++++++++++++
 tools/vm/page-types.c   |  5 ++++-
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 602e3a52884d..08cea209bae7 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1300,6 +1300,7 @@ struct pagemapread {
 #define PM_PFRAME_MASK		GENMASK_ULL(PM_PFRAME_BITS - 1, 0)
 #define PM_SOFT_DIRTY		BIT_ULL(55)
 #define PM_MMAP_EXCLUSIVE	BIT_ULL(56)
+#define PM_HWPOISON	       	BIT_ULL(60)
 #define PM_FILE			BIT_ULL(61)
 #define PM_SWAP			BIT_ULL(62)
 #define PM_PRESENT		BIT_ULL(63)
@@ -1385,6 +1386,11 @@ static pagemap_entry_t pte_to_pagemap_entry(struct p=
agemapread *pm,
 		if (is_migration_entry(entry))
 			page =3D migration_entry_to_page(entry);
=20
+		if (is_hwpoison_entry(entry)) {
+			page =3D hwpoison_entry_to_page(entry);
+			flags |=3D PM_HWPOISON;
+		}
+
 		if (is_device_private_entry(entry))
 			page =3D device_private_entry_to_page(entry);
 	}
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index d9b7c9132c2f..1b9dedbd06ab 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -323,6 +323,13 @@ static inline int is_hwpoison_entry(swp_entry_t entry)
 	return swp_type(entry) =3D=3D SWP_HWPOISON;
 }
=20
+static inline struct page *hwpoison_entry_to_page(swp_entry_t entry)
+{
+	struct page *p =3D pfn_to_page(swp_offset(entry));
+	WARN_ON(!PageHWPoison(p));
+	return p;
+}
+
 static inline void num_poisoned_pages_inc(void)
 {
 	atomic_long_inc(&num_poisoned_pages);
@@ -345,6 +352,11 @@ static inline int is_hwpoison_entry(swp_entry_t swp)
 	return 0;
 }
=20
+static inline struct page *hwpoison_entry_to_page(swp_entry_t entry)
+{
+	return NULL;
+}
+
 static inline void num_poisoned_pages_inc(void)
 {
 }
diff --git a/tools/vm/page-types.c b/tools/vm/page-types.c
index 0517c744b04e..1160d5a14955 100644
--- a/tools/vm/page-types.c
+++ b/tools/vm/page-types.c
@@ -53,6 +53,7 @@
 #define PM_SWAP_OFFSET(x)	(((x) & PM_PFRAME_MASK) >> MAX_SWAPFILES_SHIFT)
 #define PM_SOFT_DIRTY		(1ULL << 55)
 #define PM_MMAP_EXCLUSIVE	(1ULL << 56)
+#define PM_HWPOISON		(1ULL << 60)
 #define PM_FILE			(1ULL << 61)
 #define PM_SWAP			(1ULL << 62)
 #define PM_PRESENT		(1ULL << 63)
@@ -311,6 +312,8 @@ static unsigned long pagemap_pfn(uint64_t val)
=20
 	if (val & PM_PRESENT)
 		pfn =3D PM_PFRAME(val);
+	else if (val & PM_HWPOISON)
+		pfn =3D PM_SWAP_OFFSET(val);
 	else
 		pfn =3D 0;
=20
@@ -742,7 +745,7 @@ static void walk_vma(unsigned long index, unsigned long=
 count)
 			pfn =3D pagemap_pfn(buf[i]);
 			if (pfn)
 				walk_pfn(index + i, pfn, 1, buf[i]);
-			if (buf[i] & PM_SWAP)
+			else if (buf[i] & PM_SWAP)
 				walk_swap(index + i, buf[i]);
 		}
=20
--=20
2.25.1