Re: [RFC] gcc feature request: Moving blocks into sections

From: Steven Rostedt <rostedt@goodmis.org>
To: "H. Peter Anvin" <hpa@linux.intel.com>
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
Date: Tue, 06 Aug 2013 12:26:53 -0400	[thread overview]
Message-ID: <1375806413.25420.36.camel@gandalf.local.home> (raw)
In-Reply-To: <52012229.2020707@linux.intel.com>

On Tue, 2013-08-06 at 09:19 -0700, H. Peter Anvin wrote:
> 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.

Well then we just have to update the rest of the jump label code :-)

-- Steve