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From: "H. Peter Anvin" <hpa@linux.intel.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Randy Dunlap <rdunlap@xenotime.net>,
	Andy Lutomirski <luto@mit.edu>,
	x86@kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3.1-rc2] x86: fix mm/fault.c build
Date: Mon, 15 Aug 2011 22:27:16 -0700	[thread overview]
Message-ID: <4E49FFB4.8070601@linux.intel.com> (raw)
In-Reply-To: <CA+55aFxsOMc9=p02r8-QhJ=h=Mqwckk4_Pnx9LQt5+fqMp_exQ@mail.gmail.com>

On 08/15/2011 07:09 PM, Linus Torvalds wrote:
> On Mon, Aug 15, 2011 at 10:18 AM, Randy Dunlap <rdunlap@xenotime.net> wrote:
>> From: Randy Dunlap <rdunlap@xenotime.net>
>>
>> arch/x86/mm/fault.c needs to include asm/vsyscall.h to fix a
>> build error:
>>
>> arch/x86/mm/fault.c: In function '__bad_area_nosemaphore':
>> arch/x86/mm/fault.c:728: error: 'VSYSCALL_START' undeclared (first use in this function)
> 
> Grr. This seems to be one of those "under certain configurations
> only". I can trigger it with "allnoconfig", but not with my common
> configuration or "allmodconfig"
> 
> I just don't see *why* it ends up being config-related. Can anybody
> fill me in? It looks like some header file does a conditional include
> of fixmap.h or something. Urgh. I *hate* those kinds of "some configs
> work" cases.
> 

It's due to the following in <asm/smp.h>:

#ifdef CONFIG_X86_LOCAL_APIC
# include <asm/mpspec.h>
# include <asm/apic.h>
# ifdef CONFIG_X86_IO_APIC
#  include <asm/io_apic.h>
# endif
#endif

<asm/apic.h> pulls in <asm/fixmap.h> which pulls in <asm/vsyscall.h>,
bypassing the fact that arch/x86/mm/fault.c is missing <asm/vsyscall.h>.

I'll have a patch for it shortly.

	-hpa

  reply	other threads:[~2011-08-16  5:27 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-14 22:45 Linux 3.1-rc2 Linus Torvalds
2011-08-14 23:38 ` Linus Torvalds
2011-08-15  9:58 ` Paul Rolland
2011-08-15 17:18 ` [PATCH 3.1-rc2] x86: fix mm/fault.c build Randy Dunlap
2011-08-16  2:09   ` Linus Torvalds
2011-08-16  5:27     ` H. Peter Anvin [this message]
2011-08-16  6:00     ` Rule 1 (Was: Re: [PATCH 3.1-rc2] x86: fix mm/fault.c build) Stephen Rothwell
2011-08-16  6:20     ` [tip:x86/vdso] x86, vsyscall: Add missing <asm/fixmap.h> to arch/x86/mm/fault.c tip-bot for H. Peter Anvin
2011-08-16  6:43       ` Pekka Enberg
2011-08-16 15:02         ` H. Peter Anvin
2011-08-16 15:27     ` tip-bot for H. Peter Anvin
2011-08-16 17:23       ` Randy Dunlap
2011-08-16  4:41 ` [PATCH 3.1-rc2] xen: self-balloon needs module.h Randy Dunlap
2011-08-16  5:11   ` Konrad Rzeszutek Wilk

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