[PATCH 1/2] arm: hwcap: add new hwcap for identifying PXN bits

[Russell King - ARM Linux]

On Fri, Oct 24, 2014 at 06:57:34PM +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.
> 
> This patch adds new HWCAP defines to describe new feature.
> On an implementation that does not include the LPAE, PXN is
> optionally supported.

Why does userspace need to know about this?

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