fix compilation on 6.5 and shift op

[joshwyant]

reuse the patch from #151 and fix "shift exponent 32 is too large for 32-bit type 'int'" when loading the isgx module

[joshwyant]

This commit from ticapix@2f69bc4 fixes the issue #152, see #152 (comment)

[andyzyb]

It is better to use in-kernel driver instead of this one since kernel 5.11.

[joshwyant]

It is better to use in-kernel driver instead of this one since kernel 5.11.

@andyzyb In the install guide, revision 1.1 from earlier this week 4/22/24, it says, "The Out-of-Tree Driver is recommended for use on platforms that do not support or are not configured for Flexible Launch Control."

My machines don't have Flexible Launch Control.

According to the documentation, the in-kernel driver only supports /dev/sgx_enclave and /dev/sgx_provision, but not /dev/isgx; that's why I need the OOT driver. Also, it looks like I need it in order to use Rust Fortanix Enclave Development Platform as well.

[andyzyb]

Then it can only use this driver if no FLC support.

But I think Rust Fortanix EDP should also support other types of drivers as well.

[joshwyant]

Thanks! Yes, this PR will fix the driver again for us. I've tested with my setup. Before the fix it was only working for Ubuntu 16.04 and 18.04. I think this is the only driver that exists for /dev/isgx though.

[JunjunGu1]

@joshwyant I think this patch only works for the kernel which introduce vma wrapper functions.
It will fail when kernel doesn't have vma wrapper functions.