From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH RESEND 1/2] arm: hwcap: add new hwcap for identifying PXN bits
Date: Fri, 24 Oct 2014 12:53:43 +0100 [thread overview]
Message-ID: <20141024115342.GQ27405@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1414151155-26890-1-git-send-email-js07.lee@gmail.com>
On Fri, Oct 24, 2014 at 08:45:54PM +0900, Jungseung Lee wrote:
> Modern ARMv7-A/R cores can optionally implement below new
> hardware feature:
>
> - PXN:
> Privileged execute-never(PXN) is a security feature. PXN bit
> determines whether the processor can execute software from
> the region. This is effective solution against ret2usr attack.
> On an implementation that does not include the LPAE, PXN is
> optionally supported.
>
> This patch adds new HWCAP defines to describe new feature.
>
> In ARM world, elf_hwcap is used both internally in the kernel and
> for user space to keep track of optional features.
> HWCAP_PXN is exceptionally not exposed to user space since the user
> doesn't need to know.
Still no good. Adding it into elf_hwcap always exposes it to the user.
Plus, these are a limited commodity, so we don't want to waste them.
--
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.
prev parent reply other threads:[~2014-10-24 11:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-24 11:45 [PATCH RESEND 1/2] arm: hwcap: add new hwcap for identifying PXN bits Jungseung Lee
2014-10-24 11:45 ` [PATCH RESEND 2/2] arm: Support for the PXN CPU feature on ARMv7 Jungseung Lee
2014-10-24 11:53 ` Russell King - ARM Linux [this message]
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