From eeaaa96a3a2134a174100afd129bb0891d05f4b2 Mon Sep 17 00:00:00 2001 From: Don Zickus Date: Wed, 6 Jun 2012 10:05:42 -0400 Subject: [PATCH] x86/nmi: Fix section mismatch warnings on 32-bit 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() [...] 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() [...] 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 Tested-by: Witold Baryluk Cc: Jan Beulich Signed-off-by: Don Zickus Link: http://lkml.kernel.org/r/1338991542-23000-1-git-send-email-dzickus@redhat.com Signed-off-by: Ingo Molnar --- 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 0e3793b821ef..dc580c42851c 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 e31bf8d5c4d2..149b8d9c6ad4 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;