Message-ID: <52012229.2020707@linux.intel.com>
Date: Tue, 06 Aug 2013 09:19:53 -0700
From: "H. Peter Anvin" <hpa@linux.intel.com>
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To: Steven Rostedt <rostedt@goodmis.org>
CC: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>, gcc <gcc@gcc.gnu.org>,
        Ingo Molnar <mingo@kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
        David Daney <ddaney.cavm@gmail.com>,
        Behan Webster <behanw@converseincode.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Herbert Xu <herbert@gondor.hengli.com.au>
Subject: Re: [RFC] gcc feature request: Moving blocks into sections
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On 08/06/2013 09:15 AM, Steven Rostedt wrote:
> On Mon, 2013-08-05 at 14:43 -0700, H. Peter Anvin wrote:
> 
>> For unconditional jmp that should be pretty safe barring any fundamental
>> changes to the instruction set, in which case we can enable it as
>> needed, but for extra robustness it probably should skip prefix bytes.
> 
> Would the assembler add prefix bytes to:
> 
> 	jmp 1f
> 

No, but if we ever end up doing MPX in the kernel, for example, we would
have to put an MPX prefix on the jmp.

	-hpa


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