From: dave.martin@linaro.org (Dave Martin)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] [ARM] Use AT() in the linker script to create correct program headers
Date: Wed, 10 Oct 2012 10:18:29 +0100 [thread overview]
Message-ID: <20121010091829.GA2131@linaro.org> (raw)
In-Reply-To: <20121009173706.GE4124@obsidianresearch.com>
On Tue, Oct 09, 2012 at 11:37:06AM -0600, Jason Gunthorpe wrote:
> On Mon, Oct 08, 2012 at 11:24:13AM +0100, Dave Martin wrote:
>
> > Partly this came from some side speculation about whether we could do
> > things like privileged read-only permissions on newer CPUs, for preventing
> > unintended or undesired writes to the kernel's code or read-only data.
>
> Some other arches page protect the kernel, but that tends to be at
> odds with the desire to use huge pages for the kernel mapping, and
> independent of the load headers..
This wasn't so much about that headers themselves as about fragmentation
of the page permissions which makes it difficult to map everything using
huge pages / sections. But as you say, there are conflicting concerns
here, and it seems not to be a priority.
Privileged write-protect is nice to have if non-disruptive, but not
essential.
Cheers
---Dave
WARNING: multiple messages have this Message-ID (diff)
From: Dave Martin <dave.martin@linaro.org>
To: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Russell King - ARM Linux <linux@arm.linux.org.uk>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] [ARM] Use AT() in the linker script to create correct program headers
Date: Wed, 10 Oct 2012 10:18:29 +0100 [thread overview]
Message-ID: <20121010091829.GA2131@linaro.org> (raw)
In-Reply-To: <20121009173706.GE4124@obsidianresearch.com>
On Tue, Oct 09, 2012 at 11:37:06AM -0600, Jason Gunthorpe wrote:
> On Mon, Oct 08, 2012 at 11:24:13AM +0100, Dave Martin wrote:
>
> > Partly this came from some side speculation about whether we could do
> > things like privileged read-only permissions on newer CPUs, for preventing
> > unintended or undesired writes to the kernel's code or read-only data.
>
> Some other arches page protect the kernel, but that tends to be at
> odds with the desire to use huge pages for the kernel mapping, and
> independent of the load headers..
This wasn't so much about that headers themselves as about fragmentation
of the page permissions which makes it difficult to map everything using
huge pages / sections. But as you say, there are conflicting concerns
here, and it seems not to be a priority.
Privileged write-protect is nice to have if non-disruptive, but not
essential.
Cheers
---Dave
next prev parent reply other threads:[~2012-10-10 9:18 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-30 23:21 [PATCH] [ARM] Use AT() in the linker script to create correct program headers Jason Gunthorpe
2012-09-30 23:21 ` Jason Gunthorpe
2012-10-01 15:39 ` Dave Martin
2012-10-01 15:39 ` Dave Martin
2012-10-01 16:06 ` Jason Gunthorpe
2012-10-01 16:06 ` Jason Gunthorpe
2012-10-01 17:56 ` Dave Martin
2012-10-01 17:56 ` Dave Martin
2012-10-01 18:35 ` Jason Gunthorpe
2012-10-01 18:35 ` Jason Gunthorpe
2012-10-02 10:23 ` Dave Martin
2012-10-02 10:23 ` Dave Martin
2012-10-02 17:47 ` Jason Gunthorpe
2012-10-02 17:47 ` Jason Gunthorpe
2012-10-03 10:43 ` Dave Martin
2012-10-03 10:43 ` Dave Martin
2012-10-03 18:44 ` Jason Gunthorpe
2012-10-03 18:44 ` Jason Gunthorpe
2012-10-04 11:36 ` Dave Martin
2012-10-04 11:36 ` Dave Martin
2012-10-04 17:59 ` Jason Gunthorpe
2012-10-04 17:59 ` Jason Gunthorpe
2012-10-08 10:46 ` Dave Martin
2012-10-08 10:46 ` Dave Martin
2012-10-09 18:25 ` Jason Gunthorpe
2012-10-09 18:25 ` Jason Gunthorpe
2012-10-10 9:55 ` Dave Martin
2012-10-10 9:55 ` Dave Martin
2012-10-12 21:24 ` Jason Gunthorpe
2012-10-12 21:24 ` Jason Gunthorpe
2012-10-05 8:45 ` Russell King - ARM Linux
2012-10-05 8:45 ` Russell King - ARM Linux
2012-10-08 10:24 ` Dave Martin
2012-10-08 10:24 ` Dave Martin
2012-10-09 17:37 ` Jason Gunthorpe
2012-10-09 17:37 ` Jason Gunthorpe
2012-10-10 9:18 ` Dave Martin [this message]
2012-10-10 9:18 ` Dave Martin
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