Re: [PATCH 3/3] x86: Disable running 32bit processes if ia32_disabled is passed

From: Jiri Slaby
Date: Thu Jun 08 2023 - 02:29:13 EST


On 08. 06. 23, 2:25, Thomas Gleixner wrote:
For usecases where there ought not to be any 32bit code at all (and
there absolutely are), it would be lovely if this could be enforced,
rather than relying on blind hope that it doesn't happen.

I think it's rather clear what needs to be done here to achieve that,
but that's completely orthogonal to the intent of the patch series in
question which aims to make CONFIG_IA32_EMULATION a boot time decision.

Agreed. The original intent was only to disable the 32bit paths in the kernel. I.e. set CONFIG_IA32_EMULATION=n by a runtime switch.

Then we came up with idea to disallow loading 32bit binaries to WARN people as the bins won't (mostly) work anyway. (We are/were aware this doesn't forbid running 32bit code.)

But now, when we are doing that, I think we should disable 32 bits completely by the switch. I.e. don't provide 32bit segments and whatever. And make that clear and documented in the series. Because as it stands now, it's half-way. Agreed? This whole attempt served as a call for opinions which we got and which is perfect.

thanks,
--
js
suse labs