kfence: add test suite

Add KFENCE test suite, testing various error detection scenarios. Makes
use of KUnit for test organization. Since KFENCE's interface to obtain
error reports is via the console, the test verifies that KFENCE outputs
expected reports to the console.

[[email protected]: fix typo in test]
  Link: https://lkml.kernel.org/r/[email protected]
[[email protected]: show access type in report]
  Link: https://lkml.kernel.org/r/[email protected]

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Alexander Potapenko <[email protected]>
Signed-off-by: Marco Elver <[email protected]>
Reviewed-by: Dmitry Vyukov <[email protected]>
Co-developed-by: Alexander Potapenko <[email protected]>
Reviewed-by: Jann Horn <[email protected]>
Cc: Andrey Konovalov <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Christopher Lameter <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Hillf Danton <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Joern Engel <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: SeongJae Park <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 7 insertions, 2 deletions

diff --git a/include/linux/kfence.h b/include/linux/kfence.h
index 5a56bcf5606c..a70d1ea03532 100644
--- a/include/linux/kfence.h
+++ b/include/linux/kfence.h
@@ -186,6 +186,7 @@ static __always_inline __must_check bool kfence_free(void *addr)
 /**
  * kfence_handle_page_fault() - perform page fault handling for KFENCE pages
  * @addr: faulting address
+ * @is_write: is access a write
  * @regs: current struct pt_regs (can be NULL, but shows full stack trace)
  *
  * Return:
@@ -197,7 +198,7 @@ static __always_inline __must_check bool kfence_free(void *addr)
  * cases KFENCE prints an error message and marks the offending page as
  * present, so that the kernel can proceed.
  */
-bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs);
+bool __must_check kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs *regs);
 
 #else /* CONFIG_KFENCE */
 
@@ -210,7 +211,11 @@ static inline size_t kfence_ksize(const void *addr) { return 0; }
 static inline void *kfence_object_start(const void *addr) { return NULL; }
 static inline void __kfence_free(void *addr) { }
 static inline bool __must_check kfence_free(void *addr) { return false; }
-static inline bool __must_check kfence_handle_page_fault(unsigned long addr, struct pt_regs *regs) { return false; }
+static inline bool __must_check kfence_handle_page_fault(unsigned long addr, bool is_write,
+							 struct pt_regs *regs)
+{
+	return false;
+}
 
 #endif