From: Zide Chen Date: Tue, 2 Jun 2026 14:49:07 +0000 (-0700) Subject: perf/x86/intel/uncore: Fix uncore_die_to_cpu() for offline dies X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=2aa7dacf8a3d928303df9c770c1bd7f50d1f8f2a;p=thirdparty%2Fkernel%2Flinux.git perf/x86/intel/uncore: Fix uncore_die_to_cpu() for offline dies If the die is offline when uncore_die_to_cpu() is called, it silently returns 0, which is misleading. Return -1 in this case to indicate that all CPUs on the die are offline and the caller can take care of it accordingly. Opportunistically, replace -EPERM with -ENODEV, as -ENODEV is the appropriate error when no CPUs are online across all dies. Signed-off-by: Zide Chen Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Dapeng Mi Link: https://patch.msgid.link/20260602144908.263680-7-zide.chen@intel.com --- diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c index 22256ded2d67..4b3a1fa5b41b 100644 --- a/arch/x86/events/intel/uncore.c +++ b/arch/x86/events/intel/uncore.c @@ -91,7 +91,7 @@ int uncore_device_to_die(struct pci_dev *dev) */ int uncore_die_to_cpu(int die) { - int res = 0, cpu; + int res = -1, cpu; for_each_online_cpu(cpu) { if (topology_logical_die_id(cpu) == die) { diff --git a/arch/x86/events/intel/uncore_snbep.c b/arch/x86/events/intel/uncore_snbep.c index 772b78237424..334dc384b5b9 100644 --- a/arch/x86/events/intel/uncore_snbep.c +++ b/arch/x86/events/intel/uncore_snbep.c @@ -3772,12 +3772,17 @@ static void pmu_free_topology(struct intel_uncore_type *type) static int skx_pmu_get_topology(struct intel_uncore_type *type, int (*topology_cb)(struct intel_uncore_type*, int, int, u64)) { - int die, ret = -EPERM; + int die, ret = -ENODEV; u64 cpu_bus_msr; + int cpu; cpus_read_lock(); for (die = 0; die < uncore_max_dies(); die++) { - ret = skx_msr_cpu_bus_read(uncore_die_to_cpu(die), &cpu_bus_msr); + cpu = uncore_die_to_cpu(die); + if (cpu == -1) + continue; + + ret = skx_msr_cpu_bus_read(cpu, &cpu_bus_msr); if (ret) break;