Hi,
When using newer kernels on my Ultra 60 with dual 450MHz UltraSPARC-II
CPUs, I noticed that only CPU 0 comes up, while older kernels (including
4.7) are working fine with both CPUs.
I bisected the failure to this commit:
9b2f753ec23710aa32c0d837d2499db92fe9115b is the first bad commit
commit 9b2f753ec23710aa32c0d837d2499db92fe9115b
Author: Atish Patra <atish.patra@xxxxxxxxxx>
Date: Thu Sep 15 14:54:40 2016 -0600
sparc64: Fix cpu_possible_mask if nr_cpus is set
This is a small change that reverts very easily on top of 5.18: there is
just one trivial conflict. Once reverted, both CPUs work again.
Maybe this is related to the fact that the CPUs on this system are
numbered CPU0 and CPU2 (there is no CPU1)?
Here is /proc/cpuinfo on a working kernel:
% cat /proc/cpuinfo
cpu : TI UltraSparc II (BlackBird)
fpu : UltraSparc II integrated FPU
pmu : ultra12
prom : OBP 3.23.1 1999/07/16 12:08
type : sun4u
ncpus probed : 2
ncpus active : 2
D$ parity tl1 : 0
I$ parity tl1 : 0
cpucaps : flush,stbar,swap,muldiv,v9,mul32,div32,v8plus,vis
Cpu0ClkTck : 000000001ad31b4f
Cpu2ClkTck : 000000001ad31b4f
MMU Type : Spitfire
MMU PGSZs : 8K,64K,512K,4MB
State:
CPU0: online
CPU2: online
And on a broken kernel:
% cat /proc/cpuinfo
cpu : TI UltraSparc II (BlackBird)
fpu : UltraSparc II integrated FPU
pmu : ultra12
prom : OBP 3.23.1 1999/07/16 12:08
type : sun4u
ncpus probed : 2
ncpus active : 1
D$ parity tl1 : 0
I$ parity tl1 : 0
cpucaps : flush,stbar,swap,muldiv,v9,mul32,div32,v8plus,vis
Cpu0ClkTck : 000000001ad31861
MMU Type : Spitfire
MMU PGSZs : 8K,64K,512K,4MB
State:
CPU0: online
Let me know if you need any more info.
Thanks,
Nick
