[PATCH] RISC-V: io: Don't have a void* PCI_IOBASE

[Andreas Schwab]

On Mai 26 2024, Palmer Dabbelt wrote:

> I recently started noticing warnings along the lines of
>
>     include/asm-generic/io.h:752:2: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
>             insw(addr, buffer, count);
>             ^~~~~~~~~~~~~~~~~~~~~~~~~
>     arch/riscv/include/asm/io.h:105:53: note: expanded from macro 'insw'
>     #define insw(addr, buffer, count) __insw(PCI_IOBASE + (addr), buffer, count)
>
> which are triggered by having PCI_IOBASE be a "void __iomem *".  I'm not
> quite sure what the right thing to do is here: having it as u8 to make
> the pointer arithmetic work seems reasonable to me,

A u8 null pointer is still a null pointer.  Are you sure you are quoting
the right warning?  AFAICS, PCI_IOBASE is not a null pointer.

-- 
Andreas Schwab, SUSE Labs, schwab at suse.de
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