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Date: Thu, 1 Feb 2018 16:32:35 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: David Woodhouse <dwmw2@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>, 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>
Subject: Re: [PATCH 0/7] objtool: retpoline validation
Message-ID: <20180201153235.GZ2249@hirez.programming.kicks-ass.net>
References: <20180201143421.088202488@infradead.org>
 <20180201152856.okzhqvdlledykzps@treble>
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On Thu, Feb 01, 2018 at 09:28:56AM -0600, Josh Poimboeuf wrote:
> On Thu, Feb 01, 2018 at 03:34:21PM +0100, Peter Zijlstra wrote:
> > There are the retpoline validation patches; they work with the __noretpoline
> > thing from David.
> 
> Have you run this through 0-day bot yet? 

Yes, it complains a _lot_ because no retpoline supported compiler.

> A manual awk/sed found another
> one, which objtool confirms:
> 
>   drivers/watchdog/.tmp_hpwdt.o: warning: objtool: .text+0x24: indirect call found in RETPOLINE build

That is the only known one left. It calls into BIOS code, so its not
safe and using a retpoline for it is pointless since nobody audited the
BIOS code.