1 files changed, 24 insertions, 1 deletions
diff --git a/mm/maccess.c b/mm/maccess.c
index 2d3c3d01064c..3ca8d97e5010 100644
--- a/mm/maccess.c
+++ b/mm/maccess.c
@@ -43,11 +43,20 @@ probe_write_common(void __user *dst, const void *src, size_t size)
  * do_page_fault() doesn't attempt to take mmap_sem.  This makes
  * probe_kernel_read() suitable for use within regions where the caller
  * already holds mmap_sem, or other locks which nest inside mmap_sem.
+ *
+ * probe_kernel_read_strict() is the same as probe_kernel_read() except for
+ * the case where architectures have non-overlapping user and kernel address
+ * ranges: probe_kernel_read_strict() will additionally return -EFAULT for
+ * probing memory on a user address range where probe_user_read() is supposed
+ * to be used instead.
  */
 
 long __weak probe_kernel_read(void *dst, const void *src, size_t size)
     __attribute__((alias("__probe_kernel_read")));
 
+long __weak probe_kernel_read_strict(void *dst, const void *src, size_t size)
+    __attribute__((alias("__probe_kernel_read")));
+
 long __probe_kernel_read(void *dst, const void *src, size_t size)
 {
 	long ret;
@@ -157,8 +166,22 @@ EXPORT_SYMBOL_GPL(probe_user_write);
  *
  * If @count is smaller than the length of the string, copies @count-1 bytes,
  * sets the last byte of @dst buffer to NUL and returns @count.
+ *
+ * strncpy_from_unsafe_strict() is the same as strncpy_from_unsafe() except
+ * for the case where architectures have non-overlapping user and kernel address
+ * ranges: strncpy_from_unsafe_strict() will additionally return -EFAULT for
+ * probing memory on a user address range where strncpy_from_unsafe_user() is
+ * supposed to be used instead.
  */
-long strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
+
+long __weak strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
+    __attribute__((alias("__strncpy_from_unsafe")));
+
+long __weak strncpy_from_unsafe_strict(char *dst, const void *unsafe_addr,
+				       long count)
+    __attribute__((alias("__strncpy_from_unsafe")));
+
+long __strncpy_from_unsafe(char *dst, const void *unsafe_addr, long count)
 {
 	mm_segment_t old_fs = get_fs();
 	const void *src = unsafe_addr;