From: Andi Kleen <andi@firstfloor.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>,
kbuild test robot <fengguang.wu@intel.com>,
kbuild-all@01.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: arch/x86//kernel/ftrace.c:35:3: error: #error The following combination is not supported: ((compiler missing -mfentry) || (CONFIG_X86_32 and !CONFIG_DYNAMIC_FTRACE)) && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE
Date: Tue, 18 Apr 2017 13:25:19 -0700 [thread overview]
Message-ID: <20170418202519.GI22592@two.firstfloor.org> (raw)
In-Reply-To: <20170418201942.ohybixihlk36it4t@treble>
On Tue, Apr 18, 2017 at 03:19:42PM -0500, Josh Poimboeuf wrote:
> On Tue, Apr 18, 2017 at 11:52:41AM -0700, Andi Kleen wrote:
> > Josh Poimboeuf <jpoimboe@redhat.com> writes:
> > >
> > > The error is working as designed. gcc < 4.6.0 doesn't have -mfentry, so
> > > it fails the above check on x86. Can you add a skip rule? It should
> > > skip building the following case:
> > >
> > > x86 && ((gcc < 4.6.0) || (CONFIG_X86_32 and !CONFIG_DYNAMIC_FTRACE))
> > > && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE
> >
> > This will also break everyone's randconfig builds. The better way
> > would be to check this in the Makefile and disable one of the options
>
> I don't know how to disable a config option from the Makefile like that.
You just don't do something in the Makefile, e.g. don't set the -Os
For an example see the LTO Makefile here
https://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-misc.git/tree/scripts/Makefile.lto?h=lto-411-1
-Andi
next prev parent reply other threads:[~2017-04-18 20:25 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-16 1:20 arch/x86//kernel/ftrace.c:35:3: error: #error The following combination is not supported: ((compiler missing -mfentry) || (CONFIG_X86_32 and !CONFIG_DYNAMIC_FTRACE)) && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE kbuild test robot
2017-04-17 13:33 ` Josh Poimboeuf
2017-04-18 18:52 ` Andi Kleen
2017-04-18 20:19 ` Josh Poimboeuf
2017-04-18 20:25 ` Andi Kleen [this message]
2017-04-18 21:44 ` [PATCH] x86/build: convert function graph '-Os' error to warning Josh Poimboeuf
2017-04-19 8:07 ` [tip:x86/urgent] " tip-bot for Josh Poimboeuf
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