2.6.37 mainline kernel section mismatches

2.6.37 mainline kernel section mismatches

[Arvind R]

Hi,
Got 7 section mismatch warnings while compiling mainline 2.6.37 release kernel.

FILE                                   Caller Func
      Callled Func      Warnings
arch/x86/xen/enlighten.c    xen_hvm_init_shared_info    extend_brk          1
arch/x86/xen/mmu.c           xen_build_mfn_list_list
extend_brk          4

Column 2 functions need __init qualifiers; but these functions are
also called in
non __init functions in suspend.c

FILE                                   DATA
         INITIALISER        Warnings
drivers/xen/events.c           cpu_evtchn_mask_p
&init_evtchn_mask    2
Here init_evtchn_mask needs __initdata qualifier removed

Hope this is useful.
Arvind

Re: 2.6.37 mainline kernel section mismatches

[Stefano Stabellini]

On Sat, 22 Jan 2011, Arvind R wrote:
> Hi,
> Got 7 section mismatch warnings while compiling mainline 2.6.37 release kernel.
> 
> FILE                                   Caller Func
>       Callled Func      Warnings
> arch/x86/xen/enlighten.c    xen_hvm_init_shared_info    extend_brk          1
> arch/x86/xen/mmu.c           xen_build_mfn_list_list
> extend_brk          4
> 
> Column 2 functions need __init qualifiers; but these functions are
> also called in
> non __init functions in suspend.c
> 
> FILE                                   DATA
>          INITIALISER        Warnings
> drivers/xen/events.c           cpu_evtchn_mask_p
> &init_evtchn_mask    2
> Here init_evtchn_mask needs __initdata qualifier removed
> 

the appended patch by Stefan Assmann should fix the issue, I'll try to
upstream it in the next merge window.

---


From: Stefan Assmann <sassmann@redhat.com>

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@redhat.com>
---
 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;
@@ -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


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