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Venkat Reported a boot kernel panic next-20260522. Git bisect pointed tob5ea300a17("sched/cache: Make LLC id continuous") Stacktrace points to llc_mask being null. NIP [c000000000e58504] _find_first_bit+0x44/0x130 LR [c000000000e58500] _find_first_bit+0x40/0x130 Call Trace: build_sched_domains+0xad8/0xe50 sched_init_smp+0xa8/0x164 kernel_init_freeable+0x250/0x370 ret_from_kernel_user_thread+0x14/0x1c On powerpc, cpu_coregroup_mask is available only when the underlying hardware support coregroup. In shared LPAR, QEMU guest or power9 etc coregroup isn't supported. In such cases llc_mask was being referenced when it was null leading to panic. On powerpc, LLC is at SMT core level. So assumption that coregroup(MC) domain point to LLC is wrong. Provide a way for archs to say where its LLC is if it not at MC domain. Fixes:b5ea300a17("sched/cache: Make LLC id continuous") Closes: https://lore.kernel.org/all/51154de7-3700-4cb4-82f2-1b3a8fa427f7@linux.ibm.com/ Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com> Co-developed-by: Chen, Yu C <yu.c.chen@intel.com> Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Chen Yu <yu.c.chen@intel.com> Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com> Tested-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com> Link: https://patch.msgid.link/20260529075712.1181039-1-sshegde@linux.ibm.com
189 lines
4.6 KiB
C
189 lines
4.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_TOPOLOGY_H
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#define _ASM_POWERPC_TOPOLOGY_H
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#ifdef __KERNEL__
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struct device;
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struct device_node;
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struct drmem_lmb;
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#ifdef CONFIG_NUMA
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/*
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* If zone_reclaim_mode is enabled, a RECLAIM_DISTANCE of 10 will mean that
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* all zones on all nodes will be eligible for zone_reclaim().
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*/
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#define RECLAIM_DISTANCE 10
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#include <asm/mmzone.h>
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#define cpumask_of_node(node) ((node) == -1 ? \
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cpu_all_mask : \
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node_to_cpumask_map[node])
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struct pci_bus;
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#ifdef CONFIG_PCI
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extern int pcibus_to_node(struct pci_bus *bus);
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#else
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static inline int pcibus_to_node(struct pci_bus *bus)
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{
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return -1;
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}
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#endif
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#define cpumask_of_pcibus(bus) (pcibus_to_node(bus) == -1 ? \
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cpu_all_mask : \
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cpumask_of_node(pcibus_to_node(bus)))
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int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc);
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extern int __node_distance(int, int);
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#define node_distance(a, b) __node_distance(a, b)
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extern void __init dump_numa_cpu_topology(void);
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extern int sysfs_add_device_to_node(struct device *dev, int nid);
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extern void sysfs_remove_device_from_node(struct device *dev, int nid);
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static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node)
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{
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numa_cpu_lookup_table[cpu] = node;
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}
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static inline int early_cpu_to_node(int cpu)
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{
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int nid;
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nid = numa_cpu_lookup_table[cpu];
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/*
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* Fall back to node 0 if nid is unset (it should be, except bugs).
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* This allows callers to safely do NODE_DATA(early_cpu_to_node(cpu)).
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*/
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return (nid < 0) ? 0 : nid;
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}
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int of_drconf_to_nid_single(struct drmem_lmb *lmb);
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void update_numa_distance(struct device_node *node);
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extern void map_cpu_to_node(int cpu, int node);
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#ifdef CONFIG_HOTPLUG_CPU
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extern void unmap_cpu_from_node(unsigned long cpu);
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#endif /* CONFIG_HOTPLUG_CPU */
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#else
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static inline int early_cpu_to_node(int cpu) { return 0; }
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static inline void dump_numa_cpu_topology(void) {}
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static inline int sysfs_add_device_to_node(struct device *dev, int nid)
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{
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return 0;
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}
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static inline void sysfs_remove_device_from_node(struct device *dev,
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int nid)
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{
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}
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static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node) {}
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static inline int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
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{
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return 0;
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}
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static inline int of_drconf_to_nid_single(struct drmem_lmb *lmb)
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{
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return first_online_node;
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}
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static inline void update_numa_distance(struct device_node *node) {}
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#ifdef CONFIG_SMP
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static inline void map_cpu_to_node(int cpu, int node) {}
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#ifdef CONFIG_HOTPLUG_CPU
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static inline void unmap_cpu_from_node(unsigned long cpu) {}
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#endif /* CONFIG_HOTPLUG_CPU */
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#endif /* CONFIG_SMP */
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#endif /* CONFIG_NUMA */
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#if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
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void find_and_update_cpu_nid(int cpu);
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extern int cpu_to_coregroup_id(int cpu);
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#else
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static inline void find_and_update_cpu_nid(int cpu) {}
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static inline int cpu_to_coregroup_id(int cpu)
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{
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#ifdef CONFIG_SMP
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return cpu_to_core_id(cpu);
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#else
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return 0;
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#endif
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}
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#endif /* CONFIG_NUMA && CONFIG_PPC_SPLPAR */
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#include <asm-generic/topology.h>
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#ifdef CONFIG_SMP
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#include <asm/cputable.h>
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struct cpumask *cpu_coregroup_mask(int cpu);
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const struct cpumask *cpu_die_mask(int cpu);
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int cpu_die_id(int cpu);
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/*
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* Points to where the LLC is. On power9 this will point at CACHE
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* domain, On others it will point to SMT domain. In all cases
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* cpu_l2_cache_mask points to where LLC is
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*/
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#define arch_llc_mask(cpu) cpu_l2_cache_mask(cpu)
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#ifdef CONFIG_PPC64
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#include <asm/smp.h>
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#define topology_physical_package_id(cpu) (cpu_to_chip_id(cpu))
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#define topology_sibling_cpumask(cpu) (per_cpu(cpu_sibling_map, cpu))
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#define topology_core_cpumask(cpu) (per_cpu(cpu_core_map, cpu))
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#define topology_core_id(cpu) (cpu_to_core_id(cpu))
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#define topology_die_id(cpu) (cpu_die_id(cpu))
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#define topology_die_cpumask(cpu) (cpu_die_mask(cpu))
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#endif
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#endif
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#ifdef CONFIG_HOTPLUG_SMT
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#include <linux/cpu_smt.h>
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#include <linux/cpumask.h>
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#include <asm/cputhreads.h>
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static inline bool topology_is_primary_thread(unsigned int cpu)
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{
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return cpu == cpu_first_thread_sibling(cpu);
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}
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#define topology_is_primary_thread topology_is_primary_thread
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static inline bool topology_smt_thread_allowed(unsigned int cpu)
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{
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return cpu_thread_in_core(cpu) < cpu_smt_num_threads;
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}
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#define topology_is_core_online topology_is_core_online
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static inline bool topology_is_core_online(unsigned int cpu)
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{
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int i, first_cpu = cpu_first_thread_sibling(cpu);
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for (i = first_cpu; i < first_cpu + threads_per_core; ++i) {
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if (cpu_online(i))
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return true;
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}
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return false;
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}
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#endif
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_TOPOLOGY_H */
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