[PATCH v2 1/2] powerpc/io: Avoid clang null pointer arithmetic warnings

[Michael Ellerman]

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