Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754408Ab2FFOGI (ORCPT ); Wed, 6 Jun 2012 10:06:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:8749 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752529Ab2FFOGG (ORCPT ); Wed, 6 Jun 2012 10:06:06 -0400 From: Don Zickus To: Cc: LKML , baryluk@smp.if.uj.edu.pl, Don Zickus , Jan Beulich Subject: [PATCH] x86,nmi: Fix section mismatch warnings on 32-bit Date: Wed, 6 Jun 2012 10:05:42 -0400 Message-Id: <1338991542-23000-1-git-send-email-dzickus@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3847 Lines: 98 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 -- 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/