Still, I get errors:

In file included from include/asm/smp.h:12,
from include/linux/smp.h:28,
from include/linux/topology.h:33,
from include/linux/mmzone.h:683,
from include/linux/gfp.h:4,
from include/linux/kmod.h:22,
from include/linux/module.h:13,
from /home/wenwei/temp/linuxppc_new/drivers/hello/hello.c:2:
include/asm/mpspec.h:9:25: error: mach_mpspec.h: No such file or directory
In file included from include/asm/smp.h:12,
from include/linux/smp.h:28,
from include/linux/topology.h:33,
from include/linux/mmzone.h:683,
from include/linux/gfp.h:4,
from include/linux/kmod.h:22,
from include/linux/module.h:13,
from /home/wenwei/temp/linuxppc_new/drivers/hello/hello.c:2:
include/asm/mpspec.h:36: error: 'MAX_MP_BUSSES' undeclared here (not in a function)
In file included from include/asm/smp.h:15,
from include/linux/smp.h:28,
from include/linux/topology.h:33,
from include/linux/mmzone.h:683,
from include/linux/gfp.h:4,
from include/linux/kmod.h:22,
from include/linux/module.h:13,
from /home/wenwei/temp/linuxppc_new/drivers/hello/hello.c:2:
include/asm/io_apic.h:149: error: 'MAX_IRQ_SOURCES' undeclared here (not in a function)
In file included from include/linux/smp.h:28,
from include/linux/topology.h:33,
from include/linux/mmzone.h:683,
from include/linux/gfp.h:4,
from include/linux/kmod.h:22,
from include/linux/module.h:13,
from /home/wenwei/temp/linuxppc_new/drivers/hello/hello.c:2:
include/asm/smp.h:187:28: error: mach_apicdef.h: No such file or directory
In file included from include/linux/smp.h:28,
from include/linux/topology.h:33,
from include/linux/mmzone.h:683,
from include/linux/gfp.h:4,
from include/linux/kmod.h:22,
from include/linux/module.h:13,
from /home/wenwei/temp/linuxppc_new/drivers/hello/hello.c:2:
include/asm/smp.h: In function 'hard_smp_processor_id':
include/asm/smp.h:191: error: implicit declaration of function 'GET_APIC_ID'
make[2]: *** [/home/wenwei/temp/linuxppc_new/drivers/hello/hello.o] Error 1
make[1]: *** [_module_/home/wenwei/temp/linuxppc_new/drivers/hello] Error 2

BTW, my kernel is: 2.6.27-14-generic.