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Subject[PATCH] perf/x86/intel/uncore: Add Node ID mask
From: Kan Liang <>

Some PCI uncore PMUs cannot be registered on a 8-socket system (HPE
Superdome Flex).

To understand which Socket the PCI uncore PMUs belong to, perf retrieves
the local Node ID of the uncore device from CPUNODEID(0xC0) of the PCI
configuration space, and the mapping between Socket ID and Node ID from
GIDNIDMAP(0xD4). The Socket ID can be calculated accordingly.
The local Node ID is only available at bit 2:0, but current code doesn't
mask it. If a BIOS doesn't clear the rest of the bits, a wrong Node ID
will be fetched.

Filter the Node ID by adding a mask.

Fixes: 7c94ee2e0917 ("perf/x86: Add Intel Nehalem and Sandy Bridge-EP uncore support")
Reported-by: Song Liu <>
Tested-by: Song Liu <>
Signed-off-by: Kan Liang <>
arch/x86/events/intel/uncore_snbep.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c
index c07bee3..b10e043 100644
--- a/arch/x86/events/intel/uncore_snbep.c
+++ b/arch/x86/events/intel/uncore_snbep.c
@@ -1222,6 +1222,8 @@ static struct pci_driver snbep_uncore_pci_driver = {
.id_table = snbep_uncore_pci_ids,

+#define NODE_ID_MASK 0x7
* build pci bus to socket mapping
@@ -1243,7 +1245,7 @@ static int snbep_pci2phy_map_init(int devid, int nodeid_loc, int idmap_loc, bool
err = pci_read_config_dword(ubox_dev, nodeid_loc, &config);
if (err)
- nodeid = config;
+ nodeid = config & NODE_ID_MASK;
/* get the Node ID mapping */
err = pci_read_config_dword(ubox_dev, idmap_loc, &config);
if (err)
 \ /
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