Intel's Linux Shadow Stack Patches Should Work Fine With AMD CPUs

[phoronix]

Phoronix: Intel's Linux Shadow Stack Patches Should Work Fine With AMD CPUs

Intel has for a while been posting Linux kernel patches for implementing Control Flow Enforcement (CET) technology, both for the Indirect Branch Tracking and Shadow Stack features. However, as written about earlier this week, Intel is focusing on the shadow stack support for user-space. The patches posted this past week by Intel for Linux Shadow Stack for User-Space support was limited to their own processors but fortunately it's appearing to be work out fine for AMD CPUs too...

https://www.phoronix.com/scan.php?page=news_item&px=Shadow-Stacks-Linux-AMD

[schmidtbag]

This is one of those moments that makes me want to shake companies like Nvidia by the shoulder and slap them. Intel is knowingly helping AMD with this, and yet, they release it anyway.
If your hardware is good enough, you don't have to worry about your open-source efforts from helping the competition. This is especially true when the competition is also releasing stuff that helps you too.

[sinepgib]

This kinda reminds me of the Harvard architecture.

[Vorpal]

Is there any measurable performance overhead? After all the cpu will no be accessing two locations in memory on every call and ret instruction. This could possibly also result in evicting some other page that could have been in cache instead.

Michael I think you need to test this.

[mhalano]

I don't think this is not full enabled yet. I think just IBT is supported in Linux kernel today. Furthermore, I couldn't find any trace of support for Shadow Stack. I have a Intel i7-11800H CPU and it should support CET (according Intel's website) but I don't have the CPU flag SHSTK, just the IBT one.