[PATCH 0/7] RFC Memory tagging support

Richard Earnshaw Richard.Earnshaw@foss.arm.com
Mon Jun 15 17:09:08 GMT 2020


On 15/06/2020 18:04, DJ Delorie via Libc-alpha wrote:
> 
> Two immediate thoughts...
> 
> 1. Do we really want to add more environment variables as aliases for
>    new tunables?  I thought env support was for pre-tunable variable
>    support (compatibility) only.

That might depend on whether we want to try to share how this is enabled
with other C libraries - we can't expect them to copy all of glibcs
tunable API here.

That being said, this is easy enough to change if needed.

> 
> 2. Do we really need to lose the back pointer's word in allocated
>    memory?  Historically, the back pointer is *not* part of the malloc
>    internal data when the chunk is in 'allocated' state, and losing that
>    memory will make small allocations much less efficient.
> 

Yes, if you want to protect the back pointer against being trampled by
programs - it has to have a different tag colour to memory given to the
application.

R.


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