On Fri, 03 May 2024 17:56:18 +1000, Michael Ellerman wrote:
> With -Wextra clang warns about pointer arithmetic using a null pointer.
> When building with CONFIG_PCI=n, that triggers a warning in the IO
> accessors, eg:
>
> In file included from linux/arch/powerpc/include/asm/io.h:672:
> linux/arch/powerpc/include/asm/io-defs.h:23:1: warning: performing pointer
> arithmetic on a null pointer has undefined behavior
> [-Wnull-pointer-arithmetic]
> 23 | DEF_PCI_AC_RET(inb, u8, (unsigned long port), (port), pio, port)
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ...
> linux/arch/powerpc/include/asm/io.h:591:53: note: expanded from macro
> '__do_inb'
> 591 | #define __do_inb(port) readb((PCI_IO_ADDR)_IO_BASE + port);
> | ~~~~~~~~~~~~~~~~~~~~~ ^
>
> [...]
Applied to powerpc/next.
[1/2] powerpc/io: Avoid clang null pointer arithmetic warnings
https://git.kernel.org/powerpc/c/03c0f2c2b2220fc9cf8785cd7b61d3e71e24a366
[2/2] powerpc/64: Set _IO_BASE to POISON_POINTER_DELTA not 0 for CONFIG_PCI=n
https://git.kernel.org/powerpc/c/be140f1732b523947425aaafbe2e37b41b622d96
cheers
