[HN Gopher] ARM Memory Tagging: how it improves C/C++ memory saf...
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       ARM Memory Tagging: how it improves C/C++ memory safety (2018)
       [pdf]
        
       Author : fanf2
       Score  : 31 points
       Date   : 2025-10-25 20:42 UTC (2 hours ago)
        
 (HTM) web link (llvm.org)
 (TXT) w3m dump (llvm.org)
        
       | javierhonduco wrote:
       | I am incredibly happy that Apple has added MTE support to the
       | latest iPhones and perhaps the M5 chips as well (?). If that's
       | the case I don't think any other personal computers have anything
       | close to Apple machines in terms of memory safety and related
       | topics (Secure Enclave etc).
       | 
       | Hope other vendors will ship MTE in their laptop and desktop
       | chips soon enough. While I'm very positive about x86_64 adding
       | support for this (ChkTag), it'll definitely take a while...
       | 
       | In my opinion a worthwhile enough reason to upgrade but feels
       | like a waste given my current devices work great.
        
         | abalone wrote:
         | 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]
         | 
         | 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-...
        
           | commandersaki wrote:
           | Do you know if macos has the changes needed to make use of
           | MIE with M5? I assume that it has with iPadOS.
        
         | musicale wrote:
         | Compiler/runtime support via clang and llvm should help I hope.
         | 
         | I'd like to get to the point where web browsers (for example)
         | always run with memory-safe compilation and runtime features on
         | every platform. OS kernels would be nice as well.
         | 
         | It will be nice to see more OSes ship with memory safety on by
         | default for everything. Maybe OpenBSD is next?
        
       | a-dub wrote:
       | wouldn't it be like a crime against the crown to not have a cheri
       | like thing in arm?
        
         | commandersaki wrote:
         | I always see cheri brought up and admittedly I know very little
         | about it, except that the ergonomics appear poor requiring
         | twice the storage for each pointer and ground up rearchitecting
         | of the OS, making it quite unappealing from an engineering
         | standpoint.
        
       | qwertyuiop_ wrote:
       | Intel / AMD bringing this to x86 soon.
       | 
       | https://community.intel.com/t5/Blogs/Tech-Innovation/open-in...
        
       | tempaccount420 wrote:
       | Sooo, less reasons (more excuses) for people to move from C++ to
       | Rust?
        
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       (page generated 2025-10-25 23:00 UTC)