linux-kernel - [PATCH 2/2] perf/x86/intel/uncore: Fix SBOX support for Broadwell CPUs.

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Message-Id: <1479228970-15245-2-git-send-email-osk@google.com>
Date:   Tue, 15 Nov 2016 11:56:10 -0500
From:   Oskar Senft <osk@...gle.com>
To:     linux-kernel@...r.kernel.org
Cc:     kan.liang@...el.com, mark@...dzero.net,
        Oskar Senft <osk@...gle.com>
Subject: [PATCH 2/2] perf/x86/intel/uncore: Fix SBOX support for Broadwell CPUs.

This fixes SBOX support for Broadwell CPUs by checking the Power Control
Unit CAPID4 register to determine the number of available SBOXes on the
particular CPU before trying to enable them.

This patch has been tested on E5-2620 v4 (no SBOXes) and E5-2697 v4 (4
SBOXes).

Signed-off-by: Oskar Senft <osk@...gle.com>
Tested-by: Mark van Dijk <mark@...dzero.net>
Fixes: 3b94a891667c30fb4624221497d77fc65d950345
---
 arch/x86/events/intel/uncore_snbep.c | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index bcb54d7..6f4f67e 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -3054,13 +3054,26 @@ static struct intel_uncore_type *bdx_msr_uncores[] = {
 
 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)
-		uncore_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
+		bdx_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
+	/* Detect systems with no SBOXes */
+	else if (uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3]) {
+		u32 capid4;
+
+		pci_read_config_dword(
+			uncore_extra_pci_dev[pkg].dev[HSWEP_PCI_PCU_3],
+			0x94, &capid4);
+		if (((capid4 >> 6) & 0x3) == 0)
+			bdx_msr_uncores[BDX_MSR_UNCORE_SBOX] = NULL;
+	}
+
+	uncore_msr_uncores = bdx_msr_uncores;
 }
 
 static struct intel_uncore_type bdx_uncore_ha = {
@@ -3277,6 +3290,11 @@ 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 */ }
 };
 
-- 
2.8.0.rc3.226.g39d4020