adding 32 bit compatibility layer in custom kernel module

[Pradeepa Kumar]

Please see inline below

On Wed, Jan 4, 2017 at 11:07 AM, Anish Kumar <anish198519851985 at gmail.com>
wrote:

>
>
> On Jan 3, 2017, at 8:04 PM, Pradeepa Kumar <cdpradeepa at gmail.com> wrote:
>
> Hi experts
>
> down votefavorite
> <http://stackoverflow.com/questions/41455943/adding-32-bit-compatibility-layer-in-custom-kernel-module#>
>
> in my 64 bit kernel, I have a custom kernel module providing new protocol
> and providing socket system calls.
>
> it works fine when 64 bit app runs.
>
> i am seeing issues when 32 bit app runs (for exp recvmsg() call does not
> work if msg has cmsghdrs as struct size of cmsghdr is different in 32 bit
> and 64 bit).
>
> This is because my custom kernel module does not have 32 bit compatibility
> layer ( but linux kernel has this in compat.c etc).
>
>    -
>
>    is it simple to add compatibility layer to my custom kernel module
>
>
>    All you have to do is add compat_ioctl call to your driver.
>
> my kernel module provides recvmsg() but i dont see any 'compat_recvmsg' in
struct proto_ops.
had there been  'compat_recvmsg' it would have been possible for me to
define recvmsg() for 32 bit apps.
please let me know if i am missing anything


>    -
>
>    how do i do this (any links ?)
>
>
>    You can see many drivers supports compat call.
>
> Thanks
>
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