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authorDan Williams <dan.j.williams@intel.com>2018-06-08 15:16:44 -0700
committerDan Williams <dan.j.williams@intel.com>2018-06-08 15:16:44 -0700
commit930218affeadd1325ea17e053f0dcecf218f5a4f (patch)
tree203c293668a88e03b9f292cf4d5a294ca8a4275a /arch/x86/lib/usercopy_64.c
parentb56845794e1e93121acb74ca325db965035d5545 (diff)
parent5d8beee20d89e34ff1dcb0da84adf7607858c59d (diff)
Merge branch 'for-4.18/mcsafe' into libnvdimm-for-nextlibnvdimm-for-4.18
Diffstat (limited to 'arch/x86/lib/usercopy_64.c')
-rw-r--r--arch/x86/lib/usercopy_64.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c
index 75d3776123cc..7ebc9901dd05 100644
--- a/arch/x86/lib/usercopy_64.c
+++ b/arch/x86/lib/usercopy_64.c
@@ -75,6 +75,27 @@ copy_user_handle_tail(char *to, char *from, unsigned len)
return len;
}
+/*
+ * Similar to copy_user_handle_tail, probe for the write fault point,
+ * but reuse __memcpy_mcsafe in case a new read error is encountered.
+ * clac() is handled in _copy_to_iter_mcsafe().
+ */
+__visible unsigned long
+mcsafe_handle_tail(char *to, char *from, unsigned len)
+{
+ for (; len; --len, to++, from++) {
+ /*
+ * Call the assembly routine back directly since
+ * memcpy_mcsafe() may silently fallback to memcpy.
+ */
+ unsigned long rem = __memcpy_mcsafe(to, from, 1);
+
+ if (rem)
+ break;
+ }
+ return len;
+}
+
#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
/**
* clean_cache_range - write back a cache range with CLWB