Re: [PATCH v3 3/4] include/asm-generic/io.h: remove performing pointer arithmetic on a null pointer

["Arnd Bergmann" <arnd@arndb.de>]

On Tue, Dec 6, 2022, at 07:01, Song Chen wrote:
> 在 2022/12/5 18:04, Arnd Bergmann 写道:
>> On Mon, Dec 5, 2022, at 09:30, Song Chen wrote:
>> 
>> We have discussed this bit multiple times, and Niklas Schnelle
>> last posted his series to fix this as an RFC in [1].
>> 
>
> Trace triggers the warning accidentally by including io.h indirectly 
> because of the absence of PCI_IOBASE in hexagon. So what trace can do in 
> this case is either to suppress warning or just ignore it, the warning 
> will go away as long as hexagon has put PCI_IOBASE in place or 
> implemented its own inb() etc, i think they will do it sooner or later.

hexagon/riscv/s390 should not implement inb(), there is no reason
for that because no hardware uses it. Half of the other architectures
that currently implement inb() should not do so either.

> Introducing HAS_IOPORT to trace seems no necessary and too much impact.

I don't think that trace has anything to do with it, the asm-generic
header should just not provde the inb() interface on architectures
that don't use it.

    Arnd