Clang's -Wpointer-to-int-cast deviates from GCC in that it warns when casting to enums. The kernel does this in certain places, such as device tree matches to set the version of the device being used, which allows the kernel to avoid using a gigantic union. https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L428 https://elixir.bootlin.com/linux/v5.5.8/source/drivers/ata/ahci_brcm.c#L402 https://elixir.bootlin.com/linux/v5.5.8/source/include/linux/mod_devicetable.h#L264 To avoid a ton of false positive warnings, disable this particular part of the warning, which has been split off into a separate diagnostic so that the entire warning does not need to be turned off for clang. Cc: stable@xxxxxxxxxxxxxxx Link: https://github.com/ClangBuiltLinux/linux/issues/887 Link: https://github.com/llvm/llvm-project/commit/2a41b31fcdfcb67ab7038fc2ffb606fd50b83a84 Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx> --- Makefile | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/Makefile b/Makefile index 86035d866f2c..90e56d5657c9 100644 --- a/Makefile +++ b/Makefile @@ -748,6 +748,10 @@ KBUILD_CFLAGS += -Wno-tautological-compare # source of a reference will be _MergedGlobals and not on of the whitelisted names. # See modpost pattern 2 KBUILD_CFLAGS += -mno-global-merge +# clang's -Wpointer-to-int-cast warns when casting to enums, which does not match GCC. +# Disable that part of the warning because it is very noisy across the kernel and does +# not point out any real bugs. +KBUILD_CFLAGS += $(call cc-disable-warning, pointer-to-enum-cast) else # These warnings generated too much noise in a regular build. -- 2.25.1
