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

From: Don Zickus
Date: Thu Jun 07 2012 - 08:48:05 EST


On Thu, Jun 07, 2012 at 03:43:25PM +0800, Li Zhong wrote:
> 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().

Ah, ok. I forgot about the variable args syntax. That works too. I give
a quick test.

Thanks,
Don

>
> 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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