commit 98937707fe upstream.
Nick Bowler reported:
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:
9b2f753ec2 is the first bad commit
commit 9b2f753ec2
Author: Atish Patra <atish.patra@oracle.com>
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)?
The current code that adjust cpu_possible based on nr_cpu_ids do not
take into account that CPU's may not come one after each other.
Move the chech to the function that setup the cpu_possible mask
so there is no need to adjust it later.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Fixes: 9b2f753ec2 ("sparc64: Fix cpu_possible_mask if nr_cpus is set")
Reported-by: Nick Bowler <nbowler@draconx.ca>
Tested-by: Nick Bowler <nbowler@draconx.ca>
Link: https://lore.kernel.org/sparclinux/20201009161924.c8f031c079dd852941307870@gmx.de/
Link: https://lore.kernel.org/all/CADyTPEwt=ZNams+1bpMB1F9w_vUdPsGCt92DBQxxq_VtaLoTdw@mail.gmail.com/
Cc: stable@vger.kernel.org # v4.8+
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Atish Patra <atish.patra@oracle.com>
Cc: Bob Picco <bob.picco@oracle.com>
Cc: Vijay Kumar <vijay.ac.kumar@oracle.com>
Cc: David S. Miller <davem@davemloft.net>
Reviewed-by: Andreas Larsson <andreas@gaisler.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20240330-sparc64-warnings-v1-9-37201023ee2f@ravnborg.org
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
3e64c37fe3