From: Mike Rapoport <rppt@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
mm-commits@vger.kernel.org, will@kernel.org, vgupta@kernel.org,
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andreas@gaisler.com
Subject: Re: [merged mm-stable] x86-module-prepare-module-loading-for-rox-allocations-of-text.patch removed from -mm tree
Date: Fri, 6 Dec 2024 12:39:32 +0200 [thread overview]
Message-ID: <Z1LUZJdsDHrSV6oE@kernel.org> (raw)
In-Reply-To: <20241205084128.GH8562@noisy.programming.kicks-ass.net>
Hi Peter,
On Thu, Dec 05, 2024 at 09:41:28AM +0100, Peter Zijlstra wrote:
> On Wed, Nov 06, 2024 at 08:50:41AM +0200, Mike Rapoport wrote:
>
> Anyway, while noodling with all that, I think there's a fairly
> fundamental error in all of this. The mem->rw_copy should not be a whole
> second allocation, it should be a (page granular) RW alias of the
> (large) ROX map.
I've made mem->rw_copy an allocation because Andy raised a concern [1] that
we'll have an executable mapping of semi-formed code.
With an actual copy rather than an alias the ROX pages contain invalid
instructions up to the point we're through with relocations and
alternatives patching and the actual code appears in ROX mappings in one
go.
[1] https://lore.kernel.org/all/a17c65c6-863f-4026-9c6f-a04b659e9ab4@app.fastmail.com
> That also gets rid of that whole copy operation.
>
> I'm having to chase a few regressions of my own first, but after that
> I'll look at reworking all this.
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2024-12-06 10:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-11-06 1:00 [merged mm-stable] x86-module-prepare-module-loading-for-rox-allocations-of-text.patch removed from -mm tree Andrew Morton
2024-11-06 6:50 ` Mike Rapoport
2024-11-06 21:30 ` Andrew Morton
2024-12-05 8:41 ` Peter Zijlstra
2024-12-06 10:39 ` Mike Rapoport [this message]
2024-12-09 8:38 ` Peter Zijlstra
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