perf/x86/intel/cqm: Check cqm/mbm enabled state in event init

Yanqiu Zhang reported kernel panic when using mbm event
on system where CQM is detected but without mbm event
support, like with perf:

  # perf stat -e 'intel_cqm/event=3/' -a

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
  IP: [<ffffffff8100d64c>] update_sample+0xbc/0xe0
  ...
   <IRQ>
   [<ffffffff8100d688>] __intel_mbm_event_init+0x18/0x20
   [<ffffffff81113d6b>] flush_smp_call_function_queue+0x7b/0x160
   [<ffffffff81114853>] generic_smp_call_function_single_interrupt+0x13/0x60
   [<ffffffff81052017>] smp_call_function_interrupt+0x27/0x40
   [<ffffffff816fb06c>] call_function_interrupt+0x8c/0xa0
  ...

The reason is that we currently allow to init mbm event
even if mbm support is not detected.  Adding checks for
both cqm and mbm events and support into cqm's event_init.

Fixes: 33c3cc7acfd9 ("perf/x86/mbm: Add Intel Memory B/W Monitoring enumeration and init")
Reported-by: Yanqiu Zhang <[email protected]>
Signed-off-by: Jiri Olsa <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
Cc: Vikas Shivappa <[email protected]>
Cc: Tony Luck <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Thomas Gleixner <[email protected]>

0 files changed, 0 insertions, 0 deletions