Arnd Bergmann <a...@kernel.org> writes: > From: Arnd Bergmann <a...@arndb.de> > > Calling inb()/outb() on powerpc when CONFIG_PCI is disabled causes > a NULL pointer dereference, which is bad for a number of reasons. > > After my patch to turn on -Werror in linux-next, this caused a > compiler-time warning with clang: > > In file included from arch/powerpc/include/asm/io.h:672: > arch/powerpc/include/asm/io-defs.h:43:1: error: performing pointer > arithmetic on a null pointer has undefined behavior > [-Werror,-Wnull-pointer-arithmetic] > 43 | DEF_PCI_AC_NORET(insb, (unsigned long p, void *b, unsigned long c), > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 44 | (p, b, c), pio, p) > | ~~~~~~~~~~~~~~~~~~ > > In this configuration, CONFIG_HAS_IOPORT is already disabled, and all > drivers that use inb()/outb() should now depend on that (some patches are > still in the process of getting marged). > > Hide all references to inb()/outb() in the powerpc code and the definitions > when HAS_IOPORT is disabled to remove the possible NULL pointer access. > The same should happin in asm-generic in the near future, but for now > the empty inb() macros are still defined to ensure the generic version > does not get pulled in. > > Signed-off-by: Arnd Bergmann <a...@arndb.de> > Reported-by: Naresh Kamboju <naresh.kamb...@linaro.org> > --
This needs a small fixup: diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h index 86c212fcbc0c..60c80d0baf40 100644 --- a/arch/powerpc/include/asm/io.h +++ b/arch/powerpc/include/asm/io.h @@ -692,6 +692,7 @@ static inline void name at \ #define writesw writesw #define writesl writesl +#ifdef CONFIG_HAS_IOPORT #define inb inb #define inw inw #define inl inl @@ -704,6 +705,8 @@ static inline void name at \ #define outsb outsb #define outsw outsw #define outsl outsl +#endif // CONFIG_HAS_IOPORT + #ifdef __powerpc64__ #define readq readq #define writeq writeq I'm running it through some randconfig builds now. cheers