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Intel MPX had both hardware support for "bounds tables" and bounds checks[0], along with a "memory key" system[1] more similar to CHERI for memory tagging (only
by chc4 2y ago
Intel MPX had both hardware support for "bounds tables" and bounds checks[0], along with a "memory key" system[1] more similar to CHERI for memory tagging (only at page granularity, however). Both were massive failures and they are no longer supporting the extensions on new chips going forward.
0: https://www.kernel.org/doc/html/v5.5/x86/intel_mpx.html https://www.kernel.org/doc/html/v5.5/x86/intel_mpx.html
1: https://lwn.net/Articles/643797/ https://lwn.net/Articles/643797/
- pjmlp 2y agoMeanwhile Solaris Sparc is doing it since 2015, we have ongoing ARM MTE, Apple's PAC, and Microsoft with CherIoT and Pluton. Yet another example of Intel's failure to deliver.
- aseipp 2y agoMPX is dead, but memory protection keys are a distinct feature and work fine (with some limitations); I haven't seen anything about them being removed at all and Intel doesn't note them in their deprecated features list. AMD even added support for them in Zen3.
- chc4 2y agoOh, TIL. I was under the impression they were both removed , and didn't know AMD had it either.