[PATCH] Linux/x86: Enable --rosegment by default

[Michael Matz]

Hello,

On Wed, 18 Mar 2026, hev wrote:

> This patch looks acceptable to me, and it’s good to see progress here.
> That said, in some cases, -z noseparate-code can be more helpful for
> THP. I explained the reasoning in another thread. [1][2]
> 
> Also, I’m a bit curious: GNU ld with --rosegment doesn’t seem to
> arrange segments as R, RE, RW. From a security perspective, it would
> make more sense to put R first so the ELF header is not executable.

I we'd continue to care for gadget avoidance, which Florian tells us is 
not a thing anymore (yippie! :) ).

> LLVM lld with --rosegment does this by default (R, RE, RW).

But your point in these mails is to align the E part to huge-page borders.  
Putting a read-only blob in front of it defeats that purpose.

> I wonder whether relying on the current GNU ld --rosegment layout is
> entirely stable, if it ever shifts towards a more security-driven
> layout, it might not behave the way we expect here.

Hmm?  Your proposal even was to completely merge the read-only and exec 
segment into one.  You cannot at the same time care and not care about the 
security implications of merging readonly data and code :)


Ciao,
Michael.