Similar to how copy_mc_user_highpage is implemented for
copy_user_highpage on #MC supported architecture, introduce
the #MC handled version of copy_highpage.
This helper has immediate usage when khugepaged wants to copy
file-backed memory pages and tolerate #MC.
Signed-off-by: Jiaqi Yan <jiaqiyan@xxxxxxxxxx>
---
include/linux/highmem.h | 54 +++++++++++++++++++++++++++++++----------
1 file changed, 41 insertions(+), 13 deletions(-)
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 9c7cdaa3de8cd..4de1dbcd3ef64 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -315,7 +315,29 @@ static inline void copy_user_highpage(struct page *to, struct page *from,
#endif
+#ifndef __HAVE_ARCH_COPY_HIGHPAGE
+
+static inline void copy_highpage(struct page *to, struct page *from)
+{
+ char *vfrom, *vto;
+
+ vfrom = kmap_local_page(from);
+ vto = kmap_local_page(to);
+ copy_page(vto, vfrom);
+ kmsan_copy_page_meta(to, from);
+ kunmap_local(vto);
+ kunmap_local(vfrom);
+}
+
+#endif
+
#ifdef copy_mc_to_kernel
+/*
+ * If architecture supports machine check exception handling, define the
+ * #MC versions of copy_user_highpage and copy_highpage. They copy a memory
+ * page with #MC in source page (@from) handled, and return the number
+ * of bytes not copied if there was a #MC, otherwise 0 for success.
+ */
static inline int copy_mc_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma)
{
@@ -332,29 +354,35 @@ static inline int copy_mc_user_highpage(struct page *to, struct page *from,
return ret;
}
-#else
-static inline int copy_mc_user_highpage(struct page *to, struct page *from,
- unsigned long vaddr, struct vm_area_struct *vma)
-{
- copy_user_highpage(to, from, vaddr, vma);
- return 0;
-}
-#endif
-#ifndef __HAVE_ARCH_COPY_HIGHPAGE
-
-static inline void copy_highpage(struct page *to, struct page *from)
+static inline int copy_mc_highpage(struct page *to, struct page *from)
{
+ unsigned long ret;
char *vfrom, *vto;
vfrom = kmap_local_page(from);
vto = kmap_local_page(to);
- copy_page(vto, vfrom);
- kmsan_copy_page_meta(to, from);
+ ret = copy_mc_to_kernel(vto, vfrom, PAGE_SIZE);
+ if (!ret)
+ kmsan_copy_page_meta(to, from);
kunmap_local(vto);
kunmap_local(vfrom);
+
+ return ret;
+}
+#else
+static inline int copy_mc_user_highpage(struct page *to, struct page *from,
+ unsigned long vaddr, struct vm_area_struct *vma)
+{
+ copy_user_highpage(to, from, vaddr, vma);
+ return 0;
}
+static inline int copy_mc_highpage(struct page *to, struct page *from)
+{
+ copy_highpage(to, from);
+ return 0;
+}
#endif
static inline void memcpy_page(struct page *dst_page, size_t dst_off,
--
2.40.0.348.gf938b09366-goog
