Re: [PATCH] x86,nmi: Fix section mismatch warnings on 32-bit

[Li Zhong <zhong@linux.vnet.ibm.com>]

On Wed, 2012-06-06 at 10:03 -0400, Don Zickus wrote:
> On Wed, Jun 06, 2012 at 12:14:33PM +0100, Jan Beulich wrote:
> > > I didn't think it would be compiler dependent as I do not know what
> > > compiler the reporter was using.  I used a RHEL-6 4.4.4 compiler (which
> > > you probably don't have :^) ).
> > 
> > Indeed, somehow I failed to see the obvious - it's commit
> > 72b3fb24713755cf9740b403e95aa67ceedf3509 that causes
> > these problems. Instantiating static data like this just doesn't
> > play with any of the pointers passed being into .init.*.
> > 
> > I'd suggest either open coding register_nmi_handler() (with
> > the static data put into __initdata), or further abstracting it
> > by allowing an optional fifth argument (specifying the section
> > annotation if needed).
> 
> Ah.  Thanks for figuring that out!!  I will post a patch opencoding it.
> 

Hi Don, 

How about the following patch, adding an optional fifth argument as Jan
mentioned? We don't need change other users of register_nmi_handler(). 

Thanks, 
Zhong

Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com>
---
diff --git a/arch/x86/include/asm/nmi.h b/arch/x86/include/asm/nmi.h
index 0e3793b..c0fa356 100644
--- a/arch/x86/include/asm/nmi.h
+++ b/arch/x86/include/asm/nmi.h
@@ -44,14 +44,14 @@ struct nmiaction {
 	const char		*name;
 };
 
-#define register_nmi_handler(t, fn, fg, n)		\
+#define register_nmi_handler(t, fn, fg, n, init...)	\
 ({							\
-	static struct nmiaction fn##_na = {		\
+	static struct nmiaction init fn##_na = {	\
 		.handler = (fn),			\
 		.name = (n),				\
 		.flags = (fg),				\
 	};						\
-	__register_nmi_handler((t), &fn##_na);	\
+	__register_nmi_handler((t), &fn##_na);		\
 })
 
 int __register_nmi_handler(unsigned int, struct nmiaction *);
diff --git a/arch/x86/kernel/nmi_selftest.c
b/arch/x86/kernel/nmi_selftest.c
index e31bf8d..6d9582e 100644
--- a/arch/x86/kernel/nmi_selftest.c
+++ b/arch/x86/kernel/nmi_selftest.c
@@ -42,7 +42,8 @@ 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(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk",
+			__initdata);
 }
 
 static void __init cleanup_nmi_testsuite(void)
@@ -65,7 +66,7 @@ static void __init test_nmi_ipi(struct cpumask *mask)
 	unsigned long timeout;
 
 	if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback,
-				 NMI_FLAG_FIRST, "nmi_selftest")) {
+				 NMI_FLAG_FIRST, "nmi_selftest", __initdata)) {
 		nmi_fail = FAILURE;
 		return;
 	}