linux/arch/alpha
Brian Uhrain says 917b1f78a9 [PATCH] alpha: SMP boot fixes
I've encountered two problems with 2.6.16 and newer kernels on my API CS20
(dual 833MHz Alpha 21264b processors).  The first is the kernel OOPSing
because of a NULL pointer dereference while trying to populate SysFS with the
CPU information.  The other is that only one processor was being brought up.
I've included a small Alpha-specific patch that fixes both problems.

The first problem was caused by the CPUs never being properly registered using
register_cpu(), the way it's done on other architectures.

The second problem has to do with the removal of hwrpb_cpu_present_mask in
arch/alpha/kernel/smp.c.  In setup_smp() in the 2.6.15 kernel sources,
hwrpb_cpu_present_mask has a bit set for each processor that is probed, and
afterwards cpu_present_mask is set to the cpumask for the boot CPU.  In the
same function of the same file in the 2.6.16 sources, instead of
hwrpb_cpu_present_mask being set, cpu_possible_map is updated for each probed
CPU.  cpu_present_mask is still set to the cpumask of the boot CPU afterwards.
 The problem lies in include/asm-alpha/smp.h, where cpu_possible_map is
#define'd to be cpu_present_mask.

Cleanups from: Ivan Kokshaysky <ink@jurassic.park.msu.ru>

 - cpu_present_mask and cpu_possible_map are essentially the same thing
   on alpha, as it doesn't support CPU hotplug;
 - allocate "struct cpu" only for present CPUs, like sparc64 does.
   Static array of "struct cpu" is just a waste of memory.

Signed-off-by: Brian Uhrain <buhrain@rosettastone.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-11 06:18:34 -07:00
..
boot
kernel [PATCH] alpha: SMP boot fixes 2006-04-11 06:18:34 -07:00
lib [PATCH] bitops: alpha: use config options instead of __alpha_fix__ and __alpha_cix__ 2006-03-26 08:57:09 -08:00
math-emu
mm [PATCH] unify PFN_* macros 2006-03-27 08:44:48 -08:00
oprofile [PATCH] alpha gcc4 warnings 2005-08-23 18:43:43 -07:00
Kconfig [PATCH] bitops: alpha: use generic bitops 2006-03-26 08:57:11 -08:00
Kconfig.debug
Makefile kbuild: alpha,x86_64 use generic asm-offsets.h support 2005-09-09 21:28:48 +02:00
defconfig [PATCH] update all defconfigs for ARCH_DISCONTIGMEM_ENABLE 2005-06-23 09:45:02 -07:00