Received-SPF: pass (google.com: domain of linux-kernel+bounces-173344-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249;
From: Michael Ellerman <patch-notifications@ellerman.id.au>
To: linuxppc-dev@lists.ozlabs.org, Michael Ellerman <mpe@ellerman.id.au>
Cc: arnd@arndb.de, naresh.kamboju@linaro.org, linux-kernel@vger.kernel.org, nathan@kernel.org
In-Reply-To: <20240503075619.394467-1-mpe@ellerman.id.au>
References: <20240503075619.394467-1-mpe@ellerman.id.au>
Subject: Re: [PATCH v2 1/2] powerpc/io: Avoid clang null pointer arithmetic warnings
Message-Id: <171517558549.165093.14013162517942082900.b4-ty@ellerman.id.au>
Date: Wed, 08 May 2024 23:39:45 +1000
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit

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