linux-kernel - Re: [PATCH 0/7] objtool: retpoline validation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20180201193644.GM2295@hirez.programming.kicks-ass.net>
Date:   Thu, 1 Feb 2018 20:36:44 +0100
From:   Peter Zijlstra <peterz@...radead.org>
To:     Josh Poimboeuf <jpoimboe@...hat.com>
Cc:     David Woodhouse <dwmw2@...radead.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        linux-kernel@...r.kernel.org, Dave Hansen <dave.hansen@...el.com>,
        Ashok Raj <ashok.raj@...el.com>,
        Tim Chen <tim.c.chen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        Greg KH <gregkh@...uxfoundation.org>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Arjan Van De Ven <arjan.van.de.ven@...el.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Jun Nakajima <jun.nakajima@...el.com>,
        Asit Mallick <asit.k.mallick@...el.com>
Subject: Re: [PATCH 0/7] objtool: retpoline validation

On Thu, Feb 01, 2018 at 04:32:35PM +0100, Peter Zijlstra wrote:
> 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.

I think I finally got something that works there... Damn I hate
makefiles..


--- a/Makefile
+++ b/Makefile
@@ -486,6 +486,11 @@ KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG
 KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC)
 endif
 
+ifneq ($(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register),)
+  CC_HAS_RETPOLINE := 1
+endif
+export CC_HAS_RETPOLINE
+
 ifeq ($(config-targets),1)
 # ===========================================================================
 # *config targets only - make sure prerequisites are updated, and descend
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -267,8 +267,10 @@ else
 objtool_args += $(call cc-ifversion, -lt, 0405, --no-unreachable)
 endif
 ifdef CONFIG_RETPOLINE
+ifdef CC_HAS_RETPOLINE
   objtool_args += --retpoline
 endif
+endif
 
 
 ifdef CONFIG_MODVERSIONS