perf/x86/intel/uncore: Fix SBOX support for Broadwell CPUs

SBOX on some Broadwell CPUs is broken because it's enabled unconditionally
despite the fact that there are no SBOXes available.

Check the Power Control Unit CAPID4 register to determine the number of
available SBOXes on the particular CPU before trying to enable them. If
there are none, nullify the SBOX descriptor so it isn't tried to be
initialized.

Signed-off-by: Oskar Senft <osk@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Mark van Dijk <mark@voidzero.net>
Reviewed-by: Kan Liang <kan.liang@intel.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: ak@linux.intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Link: https://lkml.kernel.org/r/1521810690-2576-2-git-send-email-kan.liang@linux.intel.com

arch/x86/events/intel/uncore_snbep.c

@@ -3060,14 +3060,25 @@ static struct event_constraint bdx_uncore_pcu_constraints[] = {
 
 void bdx_uncore_cpu_init(void)
 {
+	int pkg = topology_phys_to_logical_pkg(0);
+
 	if (bdx_uncore_cbox.num_boxes > boot_cpu_data.x86_max_cores)
 		bdx_uncore_cbox.num_boxes = boot_cpu_data.x86_max_cores;
 	uncore_msr_uncores = bdx_msr_uncores;
 
 	/* BDX-DE doesn't have SBOX */
-	if (boot_cpu_data.x86_model == 86)
+	if (boot_cpu_data.x86_model == 86) {
 		uncore_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
+	/* Detect systems with no SBOXes */
+	} else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
+		struct pci_dev *pdev;
+		u32 capid4;
 
+		pdev = uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3];
+		pci_read_config_dword(pdev, 0x94, &capid4);
+		if (((capid4 >> 6) & 0x3) == 0)
+			bdx_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
+	}
 	hswep_uncore_pcu.constraints = bdx_uncore_pcu_constraints;
 }
 
@@ -3285,6 +3296,11 @@ static const struct pci_device_id bdx_uncore_pci_ids[] = {
 		PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x6f46),
 		.driver_data = UNCORE_PCI_DEV_DATA(UNCORE_EXTRA_PCI_DEV, 2),
 	},
+	{ /* PCU.3 (for Capability registers) */
+		PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x6fc0),
+		.driver_data = UNCORE_PCI_DEV_DATA(UNCORE_EXTRA_PCI_DEV,
+						   HSWEP_PCI_PCU_3),
+	},
 	{ /* end: all zeroes */ }
 };