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Date: Wed, 4 Dec 2013 17:48:17 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>, Peter Zijlstra <peterz@infradead.org>,
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        Andi Kleen <ak@linux.intel.com>, Ingo Molnar <mingo@kernel.org>,
        Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH?] uprobes: change uprobe_write_opcode() to modify the
	page directly
Message-ID: <20131204164817.GA5271@redhat.com>
References: <CA+55aFw3N=iNW2Ej6w7oksX5JDVis7QL=9X9D7JB_tKZhrjsLw@mail.gmail.com> <529E2F0C.8070405@zytor.com> <20131203200147.GB19083@redhat.com> <529E3D4C.9070403@zytor.com> <20131203203826.GA24812@redhat.com> <e6082bc4-c910-4a36-9e40-624b9319f5fb@email.android.com> <20131203205400.GA25735@redhat.com> <CA+55aFxKk+O4e51sq6iqunVWAwKfNAnZ-3=aZT-VuRpDAZUnzQ@mail.gmail.com> <20131204111125.GA26552@redhat.com> <529F51D9.7010001@zytor.com>
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On 12/04, H. Peter Anvin wrote:
>
> On 12/04/2013 03:11 AM, Oleg Nesterov wrote:
> >
> > It is still not clear to me if we can simply change a single byte on
> > x86 or not, but at least on powerpc we need to update 4 bytes. Perhaps
> > we can conditionalize these pte games later.
> >
>
> But 4 aligned bytes can be written as a single transaction.

Ah yes, this is true.

Oleg.