Re: [Xen-devel] [PATCH] xen: fix section mismatch in reference from the function xen_hvm_init_shared_info()

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 30 Nov 2010, Stefan Assmann wrote:
> From: Stefan Assmann <sassmann@xxxxxxxxxx>
> 
> The following warning shows up when building the kernel with
> make CONFIG_DEBUG_SECTION_MISMATCH=y.
> 
> WARNING: arch/x86/built-in.o(.text+0x475): Section mismatch in reference from 
> the function xen_hvm_init_shared_info() to the function 
> .init.text:extend_brk()
> The function xen_hvm_init_shared_info() references
> the function __init extend_brk().
> This is often because xen_hvm_init_shared_info lacks a __init
> annotation or the annotation of extend_brk is wrong.
> 
> The problem is that xen_hvm_init_shared_info() calls extend_brk() which is
> an __init function. However xen_hvm_init_shared_info() cannot be an
> __init function as it's called on system resume as well. Easy fix by
> moving extend_brk() out of the function.
> 
> Signed-off-by: Stefan Assmann <sassmann@xxxxxxxxxx>
> ---
>  arch/x86/xen/enlighten.c |    8 ++++----
>  1 files changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
> index 02c710b..13b11fd 100644
> --- a/arch/x86/xen/enlighten.c
> +++ b/arch/x86/xen/enlighten.c
> @@ -83,6 +83,7 @@ EXPORT_SYMBOL(machine_to_phys_order);
>  struct start_info *xen_start_info;
>  EXPORT_SYMBOL_GPL(xen_start_info);
> 
> +struct shared_info *shared_info_page;
>  struct shared_info xen_dummy_shared_info;
> 
>  void *xen_initial_gdt;

why not static?


> @@ -1310,11 +1311,7 @@ void xen_hvm_init_shared_info(void)
>  {
>       int cpu;
>       struct xen_add_to_physmap xatp;
> -     static struct shared_info *shared_info_page = 0;
> 
> -     if (!shared_info_page)
> -             shared_info_page = (struct shared_info *)
> -                     extend_brk(PAGE_SIZE, PAGE_SIZE);
>       xatp.domid = DOMID_SELF;
>       xatp.idx = 0;
>       xatp.space = XENMAPSPACE_shared_info;
> @@ -1365,6 +1362,9 @@ static void __init xen_hvm_guest_init(void)
>       if (r < 0)
>               return;
> 
> +     shared_info_page = (struct shared_info *)
> +             extend_brk(PAGE_SIZE, PAGE_SIZE);
> +
>       xen_hvm_init_shared_info();
> 
>       if (xen_feature(XENFEAT_hvm_callback_vector))
> -- 
> 1.7.3.2
> 

thanks for the patch,

Stefano

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