[RFC PATCH 3/4] mm: introduce __ptent sparse attribute

Introduce a new __ptent sparse attribute to enable type checking for
page table entries. This attribute would mark architecture-specific
pte_t type, whose pointers should only be accessed through proper
accessors, such like ptep_get(), set_pte() etc.

The corresponding sparse tool rework for this attribute is required
to cause the "dereference of PTE pointer" warning.

Signed-off-by: Alexander Gordeev <[email protected]>
---
 include/linux/compiler_types.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/compiler_types.h b/include/linux/compiler_type=
s.h
index c5921f139007..472af4fb2546 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -58,6 +58,7 @@ static inline void __chk_io_ptr(const volatile void __i=
omem *ptr) { }
 # define __nocast	__attribute__((nocast))
 # define __safe		__attribute__((safe))
 # define __private	__attribute__((noderef))
+# define __ptent	__attribute__((ptent))
 # define ACCESS_PRIVATE(p, member) (*((typeof((p)->member) __force *) &(=
p)->member))
 #else /* __CHECKER__ */
 /* address spaces */
@@ -78,6 +79,7 @@ static inline void __chk_io_ptr(const volatile void __i=
omem *ptr) { }
 # define __nocast
 # define __safe
 # define __private
+# define __ptent
 # define ACCESS_PRIVATE(p, member) ((p)->member)
 # define __builtin_warning(x, y...) (1)
 #endif /* __CHECKER__ */
--=20
2.53.0