Re: [PATCH 1/1] fs: debugfs: fix build error at powerpc platform

[Arnd Bergmann]

On Sun, Oct 1, 2023, at 07:22, Baoquan He wrote:
> On 09/29/23 at 12:49pm, Frank Li wrote:
>>    ld: fs/debugfs/file.o: in function `debugfs_print_regs':
>>    file.c:(.text+0x95a): undefined reference to `ioread64be'
>> >> ld: file.c:(.text+0x9dd): undefined reference to `ioread64'
>
> From your reproducer, on x86_64, GENERIC_IOMAP is selected. So the
> default version of ioread64 and ioread64be in asm-generic/io.h are
> bypassed. Except of those arch where ioread64 and ioread64be are
> implemented specifically like alpha, arm64, parisc, power, we may need
> include include/linux/io-64-nonatomic-hi-lo.h or
> include/linux/io-64-nonatomic-lo-hi.h to fix above linking issue?
>
> From my side, below change can fix the issue. However, I am not quite
> sure which one is chosen between io-64-nonatomic-hi-lo.h and 
> io-64-nonatomic-hi-lo.h.

It looks like the latest version of the patch only calls
it for 64-bit targets, so this question should not come up.

On 32-bit targets, it is driver specific which one you need,
so having it generic code would require passing a flag from
a driver, but I think that adds more complexity than it help.

     Arnd