Which 32-bit features are still vulnerable to "Retbleed" in the Linux kernel?

I'm updating my kernel to protect my system against the "Retbleed" exploit, and I know that affected 32-bit things haven't received the necessary mitigations . I'm wondering which 32-bit features I need to disable in the Linux kernel to be fully protected. I've found CONFIG_X86_X32_ABI and CONFIG_IA32_EMULATION so far. I'd like to maintain the ability to execute 32-bit binaries with reduced performance, if possible. **Which (or both) of these config options enable the exploit? Are there any other features I need to disable?** I'm aware that some older CPUs must disable SMT to be fully protected , but my CPU is not one of them.