Re: [PING] PCI/sysfs: Prohibit unaligned access to I/O port

[duziming <duziming2@huawei.com>]

> Unaligned access is harmful for non-x86 archs such as arm64. When we
> use pwrite or pread to access the I/O port resources with unaligned
> offset, system will crash as follows:
>
> Unable to handle kernel paging request at virtual address fffffbfffe8010c1
> Internal error: Oops: 0000000096000061 [#1] SMP
> Call trace:
>   _outw include/asm-generic/io.h:594 [inline]
>   logic_outw+0x54/0x218 lib/logic_pio.c:305
>   pci_resource_io drivers/pci/pci-sysfs.c:1157 [inline]
>   pci_write_resource_io drivers/pci/pci-sysfs.c:1191 [inline]
>   pci_write_resource_io+0x208/0x260 drivers/pci/pci-sysfs.c:1181
>   sysfs_kf_bin_write+0x188/0x210 fs/sysfs/file.c:158
>   kernfs_fop_write_iter+0x2e8/0x4b0 fs/kernfs/file.c:338
>   vfs_write+0x7bc/0xac8 fs/read_write.c:586
>   ksys_write+0x12c/0x270 fs/read_write.c:639
>   __arm64_sys_write+0x78/0xb8 fs/read_write.c:648
>
> Although x86 might handle unaligned I/O accesses by splitting cycles,
> this approach is still limited because PCI device registers typically
> expect natural alignment. A global prohibition of unaligned accesses
> ensures consistent behavior across all architectures and prevents
> unexpected hardware side effects.
Hi Bjorn,


Just a gentle ping on this patch. We have received Reviewed-by tags 
from  Ilpo Järvinen and Krzysztof.
Could you please let us know if this is queued for the upcoming merge 
window, or if you need any further action from our side?


Thank you!

ziming