x86/smp: Factor out parts of native_smp_prepare_cpus()

mainline inclusion
from mainline-v5.16-rc1
commit ce2612b6
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I8LVOX


CVE: N/A

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Intel-SIG: commit ce2612b6 x86/smp: Factor out parts of
native_smp_prepare_cpus().
Cluster scheduler feature backport.

--------------------------------

Commit 66558b73 ("sched: Add cluster scheduler level for x86")
introduced cpu_l2c_shared_map mask which is expected to be initialized
by smp_op.smp_prepare_cpus(). That commit only updated
native_smp_prepare_cpus() version but not xen_pv_smp_prepare_cpus().
As result Xen PV guests crash in set_cpu_sibling_map().

While the new mask can be allocated in xen_pv_smp_prepare_cpus() one can
see that both versions of smp_prepare_cpus ops share a number of common
operations that can be factored out. So do that instead.

Fixes: 66558b73 ("sched: Add cluster scheduler level for x86")
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lkml.kernel.org/r/1635896196-18961-1-git-send-email-boris.ostrovsky@oracle.com


Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>