path: root/Makefile
diff options
authorDaniel Wagner <>2016-03-08 09:29:09 +0100
committerMichal Marek <>2016-03-15 21:51:54 +0100
commitea8daa7b97842aab8507b5b5b1e3226cf2d514a6 (patch)
tree84e32b711078fc17dfa3c5bb1798d48023d51887 /Makefile
parent2aedcd098a9448b11eab895ee79acf519686555a (diff)
kbuild: Add option to turn incompatible pointer check into error
With the introduction of the simple wait API we have two very similar APIs in the kernel. For example wake_up() and swake_up() is only one character away. Although the compiler will warn happily the wrong usage it keeps on going an even links the kernel. Thomas and Peter would rather like to see early missuses reported as error early on. In a first attempt we tried to wrap all swait and wait calls into a macro which has an compile time type assertion. The result was pretty ugly and wasn't able to catch all wrong usages. woken_wake_function(), autoremove_wake_function() and wake_bit_function() are assigned as function pointers. Wrapping them with a macro around is not possible. Prefixing them with '_' was also not a real option because there some users in the kernel which do use them as well. All in all this attempt looked to intrusive and too ugly. An alternative is to turn the pointer type check into an error which catches wrong type uses. Obviously not only the swait/wait ones. That isn't a bad thing either. Signed-off-by: Daniel Wagner <> Acked-by: Peter Zijlstra (Intel) <> Acked-by: Thomas Gleixner <> Acked-by: Ingo Molnar <> Signed-off-by: Michal Marek <>
Diffstat (limited to 'Makefile')
1 files changed, 3 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index c65fe37c99e5..453fe00b1132 100644
--- a/Makefile
+++ b/Makefile
@@ -773,6 +773,9 @@ KBUILD_CFLAGS += $(call cc-option,-Werror=strict-prototypes)
# Prohibit date/time macros, which would make the build non-deterministic
KBUILD_CFLAGS += $(call cc-option,-Werror=date-time)
+# enforce correct pointer usage
+KBUILD_CFLAGS += $(call cc-option,-Werror=incompatible-pointer-types)
# use the deterministic mode of AR if available
KBUILD_ARFLAGS := $(call ar-option,D)