A change to include/asm-alpha/smp.h went in during 2.6.1-rc1-mm1 which
appears to have broken compilation on Alpha.  Specifically, the addition
of:
#define cpu_possible_map       cpu_present_map
seems to have caused a problem, since cpu_present_map doesn't appear to
be declared anywhere.


CC      init/main.o
In file included from init/main.c:33:
include/linux/kernel_stat.h: In function `kstat_irqs':
include/linux/kernel_stat.h:47: error: `cpu_present_map' undeclared (first use in this function)
include/linux/kernel_stat.h:47: error: (Each undeclared identifier is reported only once
include/linux/kernel_stat.h:47: error: for each function it appears in.)
init/main.c: In function `smp_init':
init/main.c:348: error: `cpu_present_map' undeclared (first use in this function)
make[1]: *** [init/main.o] Error 1
make: *** [init] Error 2


-- 
Nathan Poznick <kraken@drunkmonkey.org>

Retribution often means that we eventually do to ourselves what we have
done unto others. - Eric Hoffer