From mboxrd@z Thu Jan  1 00:00:00 1970
From: rostedt@goodmis.org (Steven Rostedt)
Date: Tue, 23 Feb 2010 13:03:05 -0500
Subject: [PATCH 04/10] ARM: ftrace: allow building without frame pointers
In-Reply-To: <20100223175807.GB5836@debian>
References: <1266090518-31120-1-git-send-email-rabin@rab.in>
	<1266090518-31120-5-git-send-email-rabin@rab.in>
	<20100222190516.GJ5055@nowhere> <1266931113.19540.5.camel@frodo>
	<20100223171112.GC5357@nowhere>  <20100223175807.GB5836@debian>
Message-ID: <1266948185.24271.6079.camel@gandalf.stny.rr.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

On Tue, 2010-02-23 at 23:28 +0530, Rabin Vincent wrote:

> The easiest option to have a more obvious message than a linker error
> would be to add something like this in entry-common.S:
> 
>   #if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4)) \
> 	&& !defined(OLD_MCOUNT)
>   #warning Ftrace on GCC < 4.4 requires frame pointers
>   #endif
> 
> Messages like this are also present in other places in ARM (for example
> arch/arm/kernel/unwind.c), so this wouldn't be this first.
> 
> Note that the above message would help in all cases except the one where
> someone builds the kernel with !fp and GCC 4.4+, and then builds a
> module with an older GCC.  That would still be only a linker error.

I was going to recommend the #if above. But shouldn't it be a #error
instead of a #warning?

-- Steve