[PATCH] x86_64: remove kernel_physical_mapping_init() from init section

[PATCH] x86_64: remove kernel_physical_mapping_init() from init section

[Gary Hade]

kernel_physical_mapping_init() is called during memory hotplug
so it does not belong in the init section.

If the kernel is built with CONFIG_DEBUG_SECTION_MISMATCH=y on
the make command line, arch/x86/mm/init_64.c is compiled with
the -fno-inline-functions-called-once gcc option defeating
inlining of kernel_physical_mapping_init() within init_memory_mapping().
When kernel_physical_mapping_init() is not inlined it is placed
in the .init.text section according to the __init in it's current
declaration.  A later call to kernel_physical_mapping_init() during
a memory hotplug operation encounters an int3 trap because the
.init.text section memory has been freed.  This patch eliminates
the crash caused by the int3 trap by moving the non-inlined
kernel_physical_mapping_init() from .init.text to .meminit.text.

Signed-off-by: Gary Hade <garyhade@us.ibm.com>

---

--- linux-2.6.29-rc2/arch/x86/mm/init_64.c.orig	2009-01-16 14:38:34.000000000 -0800
+++ linux-2.6.29-rc2/arch/x86/mm/init_64.c	2009-01-16 14:39:21.000000000 -0800
@@ -596,7 +596,7 @@ static void __init init_gbpages(void)
 		direct_gbpages = 0;
 }
 
-static unsigned long __init kernel_physical_mapping_init(unsigned long start,
+static unsigned long __meminit kernel_physical_mapping_init(unsigned long start,
 						unsigned long end,
 						unsigned long page_size_mask)
 {

Re: [PATCH] x86_64: remove kernel_physical_mapping_init() from init section

[Ingo Molnar]

* Gary Hade <garyhade@us.ibm.com> wrote:

> kernel_physical_mapping_init() is called during memory hotplug so it 
> does not belong in the init section.
> 
> If the kernel is built with CONFIG_DEBUG_SECTION_MISMATCH=y on the make 
> command line, arch/x86/mm/init_64.c is compiled with the 
> -fno-inline-functions-called-once gcc option defeating inlining of 
> kernel_physical_mapping_init() within init_memory_mapping(). When 
> kernel_physical_mapping_init() is not inlined it is placed in the 
> .init.text section according to the __init in it's current declaration.  
> A later call to kernel_physical_mapping_init() during a memory hotplug 
> operation encounters an int3 trap because the .init.text section memory 
> has been freed.  This patch eliminates the crash caused by the int3 trap 
> by moving the non-inlined kernel_physical_mapping_init() from .init.text 
> to .meminit.text.
> 
> Signed-off-by: Gary Hade <garyhade@us.ibm.com>

applied to tip/x86/urgent, thanks Gary!

	Ingo