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Date: Fri, 19 Jan 2018 00:36:52 +0900
From: Masami Hiramatsu <mhiramat@kernel.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: mhiramat@kernel.org, Ingo Molnar <mingo@kernel.org>, David Woodhouse
 <dwmw@amazon.co.uk>, linux-kernel@vger.kernel.org, Greg Kroah-Hartman
 <gregkh@linux-foundation.org>, Arjan van de Ven <arjan@linux.intel.com>,
 Peter Zijlstra <peterz@infradead.org>, Ananth N Mavinakayanahalli
 <ananth@linux.vnet.ibm.com>, Thomas Gleixner <tglx@linutronix.de>,
 "H . Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH v1 tip/master 0/3] kprobes/x86: retpoline: Fix kprobes
 for retpoline
Message-Id: <20180119003652.9842ce209b3b4aa72eb0c79e@kernel.org>
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	<20180118130157.GE7844@tassilo.jf.intel.com>
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On Thu, 18 Jan 2018 05:01:57 -0800
Andi Kleen <ak@linux.intel.com> wrote:

> > Side effect: [1/3] will move __x86_indirect_thunk_* functions
> > in kernel text area. Of course those functions were in the
> > .text area, but placed in right after _etext. This just moves
> > it right before the _etext.
> 
> I assume you tested that with page table isolation on?
> 
> The thunks need to be accessible from the trampoline.

Yes, I've tested the kernel with CONFIG_PAGE_TABLE_ISOLATION=y.
As David pointed, maybe all those points are using JMP/CALL_NOSPEC macro directly?

Thanks,

> 
> -Andi


-- 
Masami Hiramatsu <mhiramat@kernel.org>