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author | Kan Liang <kan.liang@linux.intel.com> | 2021-05-26 06:58:47 -0700 |
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committer | Peter Zijlstra <peterz@infradead.org> | 2021-05-31 10:14:51 +0200 |
commit | 4a0e3ff30980b7601b13dd3b7ee275212b852843 (patch) | |
tree | 7db5c6ee03e8c8586205215ae9819a4af8c9403f /arch/x86/events | |
parent | 6c605f8371159432ec61cbb1488dcf7ad24ad19a (diff) | |
download | linux-stable-4a0e3ff30980b7601b13dd3b7ee275212b852843.tar.gz linux-stable-4a0e3ff30980b7601b13dd3b7ee275212b852843.tar.bz2 linux-stable-4a0e3ff30980b7601b13dd3b7ee275212b852843.zip |
perf/x86/intel/uncore: Fix a kernel WARNING triggered by maxcpus=1
A kernel WARNING may be triggered when setting maxcpus=1.
The uncore counters are Die-scope. When probing a PCI device, only the
BUS information can be retrieved. The uncore driver has to maintain a
mapping table used to calculate the logical Die ID from a given BUS#.
Before the patch ba9506be4e40, the mapping table stores the mapping
information from the BUS# -> a Physical Socket ID. To calculate the
logical die ID, perf does,
- In snbep_pci2phy_map_init(), retrieve the BUS# -> a Physical Socket ID
from the UBOX PCI configure space.
- Calculate the mapping information (a BUS# -> a Physical Socket ID) for
the other PCI BUS.
- In the uncore_pci_probe(), get the physical Socket ID from a given BUS
and the mapping table.
- Calculate the logical Die ID
Since only the logical Die ID is required, with the patch ba9506be4e40,
the mapping table stores the mapping information from the BUS# -> a
logical Die ID. Now perf does,
- In snbep_pci2phy_map_init(), retrieve the BUS# -> a Physical Socket ID
from the UBOX PCI configure space.
- Calculate the logical Die ID
- Calculate the mapping information (a BUS# -> a logical Die ID) for the
other PCI BUS.
- In the uncore_pci_probe(), get the logical die ID from a given BUS and
the mapping table.
When calculating the logical Die ID, -1 may be returned, especially when
maxcpus=1. Here, -1 means the logical Die ID is not found. But when
calculating the mapping information for the other PCI BUS, -1 indicates
that it's the other PCI BUS that requires the calculation of the
mapping. The driver will mistakenly do the calculation.
Uses the -ENODEV to indicate the case which the logical Die ID is not
found. The driver will not mess up the mapping table anymore.
Fixes: ba9506be4e40 ("perf/x86/intel/uncore: Store the logical die id instead of the physical die id.")
Reported-by: John Donnelly <john.p.donnelly@oracle.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Donnelly <john.p.donnelly@oracle.com>
Tested-by: John Donnelly <john.p.donnelly@oracle.com>
Link: https://lkml.kernel.org/r/1622037527-156028-1-git-send-email-kan.liang@linux.intel.com
Diffstat (limited to 'arch/x86/events')
-rw-r--r-- | arch/x86/events/intel/uncore_snbep.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c index 63f097289a84..1587d3289743 100644 --- a/arch/x86/events/intel/uncore_snbep.c +++ b/arch/x86/events/intel/uncore_snbep.c @@ -1406,6 +1406,8 @@ static int snbep_pci2phy_map_init(int devid, int nodeid_loc, int idmap_loc, bool die_id = i; else die_id = topology_phys_to_logical_pkg(i); + if (die_id < 0) + die_id = -ENODEV; map->pbus_to_dieid[bus] = die_id; break; } @@ -1452,14 +1454,14 @@ static int snbep_pci2phy_map_init(int devid, int nodeid_loc, int idmap_loc, bool i = -1; if (reverse) { for (bus = 255; bus >= 0; bus--) { - if (map->pbus_to_dieid[bus] >= 0) + if (map->pbus_to_dieid[bus] != -1) i = map->pbus_to_dieid[bus]; else map->pbus_to_dieid[bus] = i; } } else { for (bus = 0; bus <= 255; bus++) { - if (map->pbus_to_dieid[bus] >= 0) + if (map->pbus_to_dieid[bus] != -1) i = map->pbus_to_dieid[bus]; else map->pbus_to_dieid[bus] = i; |