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Subject: Re: [PATCH 33/33] x86, pkeys: execute-only support
To: Andy Lutomirski <luto@amacapital.net>, Kees Cook <keescook@google.com>
References: <20160212210152.9CAD15B0@viggo.jf.intel.com>
 <20160212210240.CB4BB5CA@viggo.jf.intel.com>
 <CAGXu5j+L6W17wkKNdheUQQ01bJE4ZXLDiG=5JBaNWju2j9NB2Q@mail.gmail.com>
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Cc: Dave Hansen <dave.hansen@linux.intel.com>, X86 ML <x86@kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>
From: Dave Hansen <dave@sr71.net>
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Date: Wed, 17 Feb 2016 14:53:53 -0800
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On 02/17/2016 02:17 PM, Andy Lutomirski wrote:
>> > Is there a way to detect this feature's availability without userspace
>> > having to set up a segv handler and attempting to read a
>> > PROT_EXEC-only region? (i.e. cpu flag for protection keys, or a way to
>> > check the protection to see if PROT_READ got added automatically,
>> > etc?)
>> >
> We could add an HWCAP.

I'll bite.  What's an HWCAP?