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

From: Li Zhong
Date: Thu Jun 07 2012 - 03:43:35 EST


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@xxxxxxxxxxxxxxxxxx>
---
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;
}


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