Not only does M5 have MTE, it has an "enhanced" version of it.
"We conducted a deep evaluation and research process to determine whether MTE, as designed, would meet our goals for hardware-assisted memory safety. Our analysis found that, when employed as a real-time defensive measure, the original Arm MTE release exhibited weaknesses that were unacceptable to us, and we worked with Arm to address these shortcomings in the new Enhanced Memory Tagging Extension (EMTE) specification, released in 2022."[1]
Thank you for posting that. I was pretty sure the M5 was going to ship with MTE, but the last time I checked the documents, they still hadn't updated them (nor any mention of M5 having Apple10 in the metal feature tables). Some big features there that makes me want to upgrade!
"We conducted a deep evaluation and research process to determine whether MTE, as designed, would meet our goals for hardware-assisted memory safety. Our analysis found that, when employed as a real-time defensive measure, the original Arm MTE release exhibited weaknesses that were unacceptable to us, and we worked with Arm to address these shortcomings in the new Enhanced Memory Tagging Extension (EMTE) specification, released in 2022."[1]
The enhancements add:[2]
* Canonical tag checking
* Reporting of all non-address bits on a fault
* Store-only Tag checking
* Memory tagging with Address tagging disabled
[1] https://security.apple.com/blog/memory-integrity-enforcement...
[2] https://developer.arm.com/documentation/109697/0100/Feature-...