BMC/Intel-BMC/linux.git/arch/x86/kernel/smpboot.c, branch dev-4.17

x86/CPU/AMD: Have smp_num_siblings and cpu_llc_id always be present

2018-08-15T16:11:09+00:00

commit f8b64d08dde2714c62751d18ba77f4aeceb161d3 upstream. Move smp_num_siblings and cpu_llc_id to cpu/common.c so that they're always present as symbols and not only in the CONFIG_SMP case. Then, other code using them doesn't need ugly ifdeffery anymore. Get rid of some ifdeffery. Signed-off-by: Borislav Petkov Signed-off-by: Suravee Suthikulpanit Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Link: http://lkml.kernel.org/r/1524864877-111962-2-git-send-email-suravee.suthikulpanit@amd.com Signed-off-by: Guenter Roeck Signed-off-by: Greg Kroah-Hartman

x86: Don't include linux/irq.h from asm/hardirq.h

2018-08-15T16:11:07+00:00

commit 447ae316670230d7d29430e2cbf1f5db4f49d14c upstream The next patch in this series will have to make the definition of irq_cpustat_t available to entering_irq(). Inclusion of asm/hardirq.h into asm/apic.h would cause circular header dependencies like asm/smp.h asm/apic.h asm/hardirq.h linux/irq.h linux/topology.h linux/smp.h asm/smp.h or linux/gfp.h linux/mmzone.h asm/mmzone.h asm/mmzone_64.h asm/smp.h asm/apic.h asm/hardirq.h linux/irq.h linux/irqdesc.h linux/kobject.h linux/sysfs.h linux/kernfs.h linux/idr.h linux/gfp.h and others. This causes compilation errors because of the header guards becoming effective in the second inclusion: symbols/macros that had been defined before wouldn't be available to intermediate headers in the #include chain anymore. A possible workaround would be to move the definition of irq_cpustat_t into its own header and include that from both, asm/hardirq.h and asm/apic.h. However, this wouldn't solve the real problem, namely asm/harirq.h unnecessarily pulling in all the linux/irq.h cruft: nothing in asm/hardirq.h itself requires it. Also, note that there are some other archs, like e.g. arm64, which don't have that #include in their asm/hardirq.h. Remove the linux/irq.h #include from x86' asm/hardirq.h. Fix resulting compilation errors by adding appropriate #includes to *.c files as needed. Note that some of these *.c files could be cleaned up a bit wrt. to their set of #includes, but that should better be done from separate patches, if at all. Signed-off-by: Nicolai Stange Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

x86/topology: Provide topology_smt_supported()

2018-08-15T16:11:00+00:00

commit f048c399e0f7490ab7296bc2c255d37eb14a9675 upstream Provide information whether SMT is supoorted by the CPUs. Preparatory patch for SMT control mechanism. Suggested-by: Dave Hansen Signed-off-by: Thomas Gleixner Acked-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/smp: Provide topology_is_primary_thread()

2018-08-15T16:11:00+00:00

commit 6a4d2657e048f096c7ffcad254010bd94891c8c0 upstream If the CPU is supporting SMT then the primary thread can be found by checking the lower APIC ID bits for zero. smp_num_siblings is used to build the mask for the APIC ID bits which need to be taken into account. This uses the MPTABLE or ACPI/MADT supplied APIC ID, which can be different than the initial APIC ID in CPUID. But according to AMD the lower bits have to be consistent. Intel gave a tentative confirmation as well. Preparatory patch to support disabling SMT at boot/runtime. Signed-off-by: Thomas Gleixner Reviewed-by: Konrad Rzeszutek Wilk Acked-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/speculation: Handle HT correctly on AMD

2018-05-17T15:09:18+00:00

The AMD64_LS_CFG MSR is a per core MSR on Family 17H CPUs. That means when hyperthreading is enabled the SSBD bit toggle needs to take both cores into account. Otherwise the following situation can happen: CPU0 CPU1 disable SSB disable SSB enable SSB <- Enables it for the Core, i.e. for CPU0 as well So after the SSB enable on CPU1 the task on CPU0 runs with SSB enabled again. On Intel the SSBD control is per core as well, but the synchronization logic is implemented behind the per thread SPEC_CTRL MSR. It works like this: CORE_SPEC_CTRL = THREAD0_SPEC_CTRL | THREAD1_SPEC_CTRL i.e. if one of the threads enables a mitigation then this affects both and the mitigation is only disabled in the core when both threads disabled it. Add the necessary synchronization logic for AMD family 17H. Unfortunately that requires a spinlock to serialize the access to the MSR, but the locks are only shared between siblings. Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Reviewed-by: Konrad Rzeszutek Wilk

x86/smpboot: Don't use mwait_play_dead() on AMD systems

2018-04-26T14:06:19+00:00

Recent AMD systems support using MWAIT for C1 state. However, MWAIT will not allow deeper cstates than C1 on current systems. play_dead() expects to use the deepest state available. The deepest state available on AMD systems is reached through SystemIO or HALT. If MWAIT is available, it is preferred over the other methods, so the CPU never reaches the deepest possible state. Don't try to use MWAIT to play_dead() on AMD systems. Instead, use CPUIDLE to enter the deepest state advertised by firmware. If CPUIDLE is not available then fallback to HALT. Signed-off-by: Yazen Ghannam Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: stable@vger.kernel.org Cc: Yazen Ghannam Link: https://lkml.kernel.org/r/20180403140228.58540-1-Yazen.Ghannam@amd.com

x86,sched: Allow topologies where NUMA nodes share an LLC

2018-04-17T13:39:55+00:00

Intel's Skylake Server CPUs have a different LLC topology than previous generations. When in Sub-NUMA-Clustering (SNC) mode, the package is divided into two "slices", each containing half the cores, half the LLC, and one memory controller and each slice is enumerated to Linux as a NUMA node. This is similar to how the cores and LLC were arranged for the Cluster-On-Die (CoD) feature. CoD allowed the same cache line to be present in each half of the LLC. But, with SNC, each line is only ever present in *one* slice. This means that the portion of the LLC *available* to a CPU depends on the data being accessed: Remote socket: entire package LLC is shared Local socket->local slice: data goes into local slice LLC Local socket->remote slice: data goes into remote-slice LLC. Slightly higher latency than local slice LLC. The biggest implication from this is that a process accessing all NUMA-local memory only sees half the LLC capacity. The CPU describes its cache hierarchy with the CPUID instruction. One of the CPUID leaves enumerates the "logical processors sharing this cache". This information is used for scheduling decisions so that tasks move more freely between CPUs sharing the cache. But, the CPUID for the SNC configuration discussed above enumerates the LLC as being shared by the entire package. This is not 100% precise because the entire cache is not usable by all accesses. But, it *is* the way the hardware enumerates itself, and this is not likely to change. The userspace visible impact of all the above is that the sysfs info reports the entire LLC as being available to the entire package. As noted above, this is not true for local socket accesses. This patch does not correct the sysfs info. It is the same, pre and post patch. The current code emits the following warning: sched: CPU #3's llc-sibling CPU #0 is not on the same node! [node: 1 != 0]. Ignoring dependency. The warning is coming from the topology_sane() check in smpboot.c because the topology is not matching the expectations of the model for obvious reasons. To fix this, add a vendor and model specific check to never call topology_sane() for these systems. Also, just like "Cluster-on-Die" disable the "coregroup" sched_domain_topology_level and use NUMA information from the SRAT alone. This is OK at least on the hardware we are immediately concerned about because the LLC sharing happens at both the slice and at the package level, which are also NUMA boundaries. Signed-off-by: Alison Schofield Signed-off-by: Thomas Gleixner Reviewed-by: Borislav Petkov Cc: Prarit Bhargava Cc: Tony Luck Cc: Peter Zijlstra (Intel) Cc: brice.goglin@gmail.com Cc: Dave Hansen Cc: Borislav Petkov Cc: David Rientjes Cc: Igor Mammedov Cc: "H. Peter Anvin" Cc: Tim Chen Link: https://lkml.kernel.org/r/20180407002130.GA18984@alison-desk.jf.intel.com

x86/topology: Update the 'cpu cores' field in /proc/cpuinfo correctly across CPU hotplug operations

2018-02-23T07:47:47+00:00

Without this fix, /proc/cpuinfo will display an incorrect amount of CPU cores, after bringing them offline and online again, as exemplified below: $ cat /proc/cpuinfo | grep cores cpu cores : 4 cpu cores : 8 cpu cores : 8 cpu cores : 20 cpu cores : 4 cpu cores : 3 cpu cores : 2 cpu cores : 2 This patch fixes this by always zeroing the booted_cores variable upon turning off a logical CPU. Tested-by: Dou Liyang Signed-off-by: Samuel Neves Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: jgross@suse.com Cc: luto@kernel.org Cc: prarit@redhat.com Cc: vkuznets@redhat.com Link: http://lkml.kernel.org/r/20180221205036.5244-1-sneves@dei.uc.pt Signed-off-by: Ingo Molnar

x86/xen: Calculate __max_logical_packages on PV domains

2018-02-17T08:40:45+00:00

The kernel panics on PV domains because native_smp_cpus_done() is only called for HVM domains. Calculate __max_logical_packages for PV domains. Fixes: b4c0a7326f5d ("x86/smpboot: Fix __max_logical_packages estimate") Signed-off-by: Prarit Bhargava Tested-and-reported-by: Simon Gaiser Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: Boris Ostrovsky Cc: Juergen Gross Cc: Dou Liyang Cc: Prarit Bhargava Cc: Kate Stewart Cc: Greg Kroah-Hartman Cc: Andy Lutomirski Cc: Andi Kleen Cc: Vitaly Kuznetsov Cc: xen-devel@lists.xenproject.org Reviewed-by: Boris Ostrovsky Signed-off-by: Juergen Gross

x86/smpboot: Fix uncore_pci_remove() indexing bug when hot-removing a physical CPU

2018-02-13T11:47:28+00:00

When a physical CPU is hot-removed, the following warning messages are shown while the uncore device is removed in uncore_pci_remove(): WARNING: CPU: 120 PID: 5 at arch/x86/events/intel/uncore.c:988 uncore_pci_remove+0xf1/0x110 ... CPU: 120 PID: 5 Comm: kworker/u1024:0 Not tainted 4.15.0-rc8 #1 Workqueue: kacpi_hotplug acpi_hotplug_work_fn ... Call Trace: pci_device_remove+0x36/0xb0 device_release_driver_internal+0x145/0x210 pci_stop_bus_device+0x76/0xa0 pci_stop_root_bus+0x44/0x60 acpi_pci_root_remove+0x1f/0x80 acpi_bus_trim+0x54/0x90 acpi_bus_trim+0x2e/0x90 acpi_device_hotplug+0x2bc/0x4b0 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x141/0x340 worker_thread+0x47/0x3e0 kthread+0xf5/0x130 When uncore_pci_remove() runs, it tries to get the package ID to clear the value of uncore_extra_pci_dev[].dev[] by using topology_phys_to_logical_pkg(). The warning messesages are shown because topology_phys_to_logical_pkg() returns -1. arch/x86/events/intel/uncore.c: static void uncore_pci_remove(struct pci_dev *pdev) { ... phys_id = uncore_pcibus_to_physid(pdev->bus); ... pkg = topology_phys_to_logical_pkg(phys_id); // returns -1 for (i = 0; i < UNCORE_EXTRA_PCI_DEV_MAX; i++) { if (uncore_extra_pci_dev[pkg].dev[i] == pdev) { uncore_extra_pci_dev[pkg].dev[i] = NULL; break; } } WARN_ON_ONCE(i >= UNCORE_EXTRA_PCI_DEV_MAX); // <=========== HERE!! topology_phys_to_logical_pkg() tries to find cpuinfo_x86->phys_proc_id that matches the phys_pkg argument. arch/x86/kernel/smpboot.c: int topology_phys_to_logical_pkg(unsigned int phys_pkg) { int cpu; for_each_possible_cpu(cpu) { struct cpuinfo_x86 *c = &cpu_data(cpu); if (c->initialized && c->phys_proc_id == phys_pkg) return c->logical_proc_id; } return -1; } However, the phys_proc_id was already set to 0 by remove_siblinginfo() when the CPU was offlined. So, topology_phys_to_logical_pkg() cannot find the correct logical_proc_id and always returns -1. As the result, uncore_pci_remove() calls WARN_ON_ONCE() and the warning messages are shown. What is worse is that the bogus 'pkg' index results in two bugs: - We dereference uncore_extra_pci_dev[] with a negative index - We fail to clean up a stale pointer in uncore_extra_pci_dev[][] To fix these bugs, remove the clearing of ->phys_proc_id from remove_siblinginfo(). This should not cause any problems, because ->phys_proc_id is not used after it is hot-removed and it is re-set while hot-adding. Signed-off-by: Masayoshi Mizuma Acked-by: Thomas Gleixner Cc: Linus Torvalds Cc: Peter Zijlstra Cc: yasu.isimatu@gmail.com Cc: Fixes: 30bb9811856f ("x86/topology: Avoid wasting 128k for package id array") Link: http://lkml.kernel.org/r/ed738d54-0f01-b38b-b794-c31dc118c207@gmail.com Signed-off-by: Ingo Molnar