I'm running amd64 UP. I get this message when I compile:
LD vmlinux.o
MODPOST vmlinux.o
WARNING: modpost: Found 3541 section mismatch(es).
To see full details build your kernel with:
'make CONFIG_DEBUG_SECTION_MISMATCH=y'
GEN .version
CHK include/linux/compile.h
UPD include/linux/compile.h
CC init/version.o
LD init/built-in.o
LD vmlinux
arch/x86/kernel/built-in.o: In function `debug':
(.kprobes.text+0x83): undefined reference to `per_cpu__cpu_number'
arch/x86/kernel/built-in.o: In function `int3':
(.kprobes.text+0xc3): undefined reference to `per_cpu__cpu_number'
make[1]: *** [vmlinux] Error 1
make[1]: Leaving directory `/usr/src/linux-2.6.30'
make: *** [debian/stamp/build/kernel] Error 2