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Date: Tue, 23 Jan 2018 17:03:50 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Josh Poimboeuf <jpoimboe@redhat.com>, linux-kernel@vger.kernel.org,
	Dave Hansen <dave.hansen@intel.com>,
	Ashok Raj <ashok.raj@intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andi Kleen <ak@linux.intel.com>,
	Arjan Van De Ven <arjan.van.de.ven@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Jun Nakajima <jun.nakajima@intel.com>,
	Asit Mallick <asit.k.mallick@intel.com>,
	Jason Baron <jbaron@akamai.com>
Subject: Re: [PATCH 00/24] objtool: retpoline and asm-goto validation
Message-ID: <20180123160350.GK2228@hirez.programming.kicks-ass.net>
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On Tue, Jan 23, 2018 at 03:57:39PM +0000, David Woodhouse wrote:
> On Tue, 2018-01-23 at 16:42 +0100, Peter Zijlstra wrote:
> > drivers/watchdog/.tmp_hpwdt.o: warning: objtool: .text+0x24: indirect call found in RETPOLINE build
> 
> You're calling into BIOS there. Not a lot of point in protecting that
> one. This is one of the cases where we were saying you needed to turn
> on IBRS to have complete protection, even with retpoline.
> 

That code looked entirely dodgy, which is why I left it. I can easily
add the ANNOTATE_RETPOLINE_SAFE thing to shut it up, but given it is an
actual problem, maybe we should just keep it?