+/*
+ * Machine check exception handled version of copy_highpage.
+ * Return true if copying page content failed; otherwise false.
+ * Note handling #MC requires arch opt-in.
+ */
+static inline bool copy_highpage_mc(struct page *to, struct page *from)
+{
+ char *vfrom, *vto;
+ unsigned long ret;
+
+ vfrom = kmap_local_page(from);
+ vto = kmap_local_page(to);
+ ret = copy_mc_to_kernel(vto, vfrom, PAGE_SIZE);
+ kunmap_local(vto);
+ kunmap_local(vfrom);
+
+ return ret > 0;
+}
Andrew Morton took my patches to recover from copy-on-write faults
into the -mm tree. They are now sitting in linux-next (hopefully) ready
for the next merge window.
I had copied this function from an earlier version of your patch, but
there was a suggestion that copy_mc_user_highpage() would be a
more consistent name with other copy code that can handle machine
checks. There was also an upstream change to copy_highpage()
that needed to be reflected here.
Net result, this version is already in flight:
static inline int copy_mc_user_highpage(struct page *to, struct page *from,
unsigned long vaddr, struct vm_area_struct *vma)
{
unsigned long ret;
char *vfrom, *vto;
vfrom = kmap_local_page(from);
vto = kmap_local_page(to);
ret = copy_mc_to_kernel(vto, vfrom, PAGE_SIZE);
if (!ret)
kmsan_unpoison_memory(page_address(to), PAGE_SIZE);
kunmap_local(vto);
kunmap_local(vfrom);
return ret;
}
-Tony
