From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: 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 15:19:42 -0500 [thread overview]
Message-ID: <20170418201942.ohybixihlk36it4t@treble> (raw)
In-Reply-To: <87lgqxtuo6.fsf@firstfloor.org>
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.
Any ideas?
BTW, I think it will only break randconfigs for old versions of gcc,
before 4.6.0. The error message isn't quite right. I just noticed the
FUNCTION_GRAPH_TRACER config has:
depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
which means that X86_32 and CC_OPTIMIZE_FOR_SIZE can never be set with
FUNCTION_GRAPH_TRACER. So the error message could be simplified to:
#error The following combination is not supported: (compiler missing -mfentry) && CONFIG_FUNCTION_GRAPH_TRACER && CONFIG_CC_OPTIMIZE_FOR_SIZE
--
Josh
next prev parent reply other threads:[~2017-04-18 20:19 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 [this message]
2017-04-18 20:25 ` Andi Kleen
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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