Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754061Ab2FFVWK (ORCPT ); Wed, 6 Jun 2012 17:22:10 -0400 Received: from smp.if.uj.edu.pl ([149.156.82.206]:46850 "EHLO smp.if.uj.edu.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750703Ab2FFVWH (ORCPT ); Wed, 6 Jun 2012 17:22:07 -0400 Date: Wed, 6 Jun 2012 23:22:01 +0200 From: Witold Baryluk To: Don Zickus Cc: x86@kernel.org, LKML , Jan Beulich Subject: Re: [PATCH] x86,nmi: Fix section mismatch warnings on 32-bit Message-ID: <20120606212201.GH5511@smp.if.uj.edu.pl> References: <1338991542-23000-1-git-send-email-dzickus@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline In-Reply-To: <1338991542-23000-1-git-send-email-dzickus@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4157 Lines: 107 On 06-06 10:05, Don Zickus wrote: > It was reported that compiling for 32-bit caused a bunch of section > mismatch warnings: > > VDSOSYM arch/x86/vdso/vdso32-syms.lds > LD arch/x86/vdso/built-in.o > LD arch/x86/built-in.o > WARNING: arch/x86/built-in.o(.data+0x5af0): Section mismatch in reference from the variable > test_nmi_ipi_callback_na.10451 to the function .init.text:test_nmi_ipi_callback() > The variable test_nmi_ipi_callback_na.10451 references > the function __init test_nmi_ipi_callback() > If the reference is valid then annotate the > variable with __init* or __refdata (see linux/init.h) or name the variable: > *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console > > WARNING: arch/x86/built-in.o(.data+0x5b04): Section mismatch in reference from the variable > nmi_unk_cb_na.10399 to the function .init.text:nmi_unk_cb() > The variable nmi_unk_cb_na.10399 references > the function __init nmi_unk_cb() > If the reference is valid then annotate the > variable with __init* or __refdata (see linux/init.h) or name the variable: > *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console > > Both of these are attributed to the internal representation of the nmiaction > struct created during register_nmi_handler. The reason for this is that those > structs are not defined in the init section whereas the rest of the code in > nmi_selftest.c is. > > To resolve this, I created a new #define, register_nmi_handler_initonly, that > tags the struct as __initdata to resolve the mismatch. This #define should > only be used in rare situations where the register/unregister is called during > init of the kernel. > > Big thanks to Jan Beulich for decoding this for me as I didn't have a clue > what was going on. > > Reported-by: Witold Baryluk > Cc: Jan Beulich > Signed-off-by: Don Zickus > --- > arch/x86/include/asm/nmi.h | 14 ++++++++++++++ > arch/x86/kernel/nmi_selftest.c | 4 ++-- > 2 files changed, 16 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h > index 0e3793b..dc580c4 100644 > --- a/arch/x86/include/asm/nmi.h > +++ b/arch/x86/include/asm/nmi.h > @@ -54,6 +54,20 @@ struct nmiaction { > __register_nmi_handler((t), &fn##_na); \ > }) > > +/* > + * For special handlers that register/unregister in the > + * init section only. This should be considered rare. > + */ > +#define register_nmi_handler_initonly(t, fn, fg, n) \ > +({ \ > + static struct nmiaction fn##_na __initdata = { \ > + .handler = (fn), \ > + .name = (n), \ > + .flags = (fg), \ > + }; \ > + __register_nmi_handler((t), &fn##_na); \ > +}) > + > int __register_nmi_handler(unsigned int, struct nmiaction *); > > void unregister_nmi_handler(unsigned int, const char *); > diff --git a/arch/x86/kernel/nmi_selftest.c b/arch/x86/kernel/nmi_selftest.c > index e31bf8d..149b8d9 100644 > --- a/arch/x86/kernel/nmi_selftest.c > +++ b/arch/x86/kernel/nmi_selftest.c > @@ -42,7 +42,7 @@ static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs) > static void __init init_nmi_testsuite(void) > { > /* trap all the unknown NMIs we may generate */ > - register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk"); > + register_nmi_handler_initonly(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk"); > } > > static void __init cleanup_nmi_testsuite(void) > @@ -64,7 +64,7 @@ static void __init test_nmi_ipi(struct cpumask *mask) > { > unsigned long timeout; > > - if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback, > + if (register_nmi_handler_initonly(NMI_LOCAL, test_nmi_ipi_callback, > NMI_FLAG_FIRST, "nmi_selftest")) { > nmi_fail = FAILURE; > return; > -- > 1.7.7.6 > Works for me. Tested-by: Witold Baryluk -- Witold Baryluk -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/