[ Upstream commit fd636b6a9bc6034f2e5bb869658898a2b472c037 ] Some of Nano series processors will lead GP when accessing PMC fixed counter. Meanwhile, their hardware support for PMC has not announced externally. So exclude Nano CPUs from ZXC by checking stepping information. This is an unambiguous way to differentiate between ZXC and Nano CPUs. Following are Nano and ZXC FMS information: Nano FMS: Family=6, Model=F, Stepping=[0-A][C-D] ZXC FMS: Family=6, Model=F, Stepping=E-F OR Family=6, Model=0x19, Stepping=0-3 Fixes: 3a4ac121c2ca ("x86/perf: Add hardware performance events support for Zhaoxin CPU.") Reported-by: Arjan <8vvbbqzo567a@nospam.xutrox.com> Reported-by: Kevin Brace <kevinbrace@gmx.com> Signed-off-by: silviazhao <silviazhao-oc@zhaoxin.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://bugzilla.kernel.org/show_bug.cgi?id=212389 Signed-off-by: Sasha Levin <sashal@kernel.org>