Detect MIPS CPU options

[michael-roe]

A commit to the Linux kernel on 24 October 2021 extended /proc/cpuinfo on MIPS to include information about CPU options.

The CPU options include nan2008 (I.e. whether the FPU is supporting the 2008 version of the IEEE 754 standard or the earlier version). User space software sometimes needs to know this, so that it can use a math library appropriate for the floating point hardware.

To facilitate this, cpu_features should check for nan2008 in /proc/cpuinfo and set a flag in the options structure.

(if I have time, I'll write this and submit a pull request).

[gchatelet]

Patch welcome if you have a bit of time.

[jculpon]

xoogler who is subscribed to this bug: has this been merged into cpu_features public?

I don't see it as so on GitHub, but want to make sure I'm pulling latest source from here or Google official while recompiling things related to RedBleed.

[gchatelet]

I don't see how this patch could be related to RetBleed since it targets x86 cpus (Intel/AMD). That being said, #241 adds some additional detection options but not the one about nan2008.

Also what do you mean by Google official? Can you provide a link?

[jculpon]

Bonjour, @gchatelet! I am up too early in USA/ARIZONA TZ to know what CPU cores are and ARM-not x86_64(AMD) vs x86_64(INTEL) vs ARMvFoo. By @google official I just mean the vendored version of this library that is distributed via nightly builds, not chromium/WebKit or via KHTML-LIKE-GECKO browsers on tablets running INTEL ATOM or AMD LOW POWER MODE devices.

If it’s not adding the one about nan2008, I’m not concerned with this as a NETWORK/SECURITY issue, but I’m trying to “repackage” a few indie games (see @jculpon vs. Punch Elvis GAMES here at GitHub) in reaction to critical vulnerabilities on x86/x86_64 jouex électronique.

Si vous voudrais, email a jculpon+security @ GitHub email for more infos/warn.