perf/x86/intel: Handle new arch perfmon v4 status bits

ArchPerfmon v4 has some new status bits in GLOBAL_STATUS.

These need to be ignored when deciding whether a NMI
was an NMI, to avoid eating all NMIs when they
stay set, see:

    b292d7a1 ("perf/x86/intel: ignore CondChgd bit to avoid false NMI handling")

This patch ignores the new ASIF bit, which indicates
that SGX interfered with the PMU, and also the new
LBR freezing bits, which are set when the LBRs get
frozen, plus the existing CondChange (set by JTAG
debuggers and some buggy BIOSes)
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1431285767-27027-8-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

arch/x86/kernel/cpu/perf_event_intel.c

@@ -1611,13 +1611,14 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 	intel_pmu_lbr_read();
 
 	/*
-	 * CondChgd bit 63 doesn't mean any overflow status. Ignore
-	 * and clear the bit.
+	 * Ignore a range of extra bits in status that do not indicate
+	 * overflow by themselves.
 	 */
-	if (__test_and_clear_bit(63, (unsigned long *)&status)) {
-		if (!status)
-			goto done;
-	}
+	status &= ~(GLOBAL_STATUS_COND_CHG |
+		    GLOBAL_STATUS_ASIF |
+		    GLOBAL_STATUS_LBRS_FROZEN);
+	if (!status)
+		goto done;
 
 	/*
 	 * PEBS overflow sets bit 62 in the global status register