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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2025-09-26 13:44:21 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2025-09-26 13:44:21 -0700 |
| commit | d4df17482e963e5424da63f22010976d1656a4b0 (patch) | |
| tree | 9bf58c2bf3c2fa25335a94afcdf4e85e33381dd7 | |
| parent | 083fc6d7fa0d974a3663b97c8b0466737a544236 (diff) | |
| parent | 2066f00e5b2dc061fb6d8c88fadaebc97f11feaa (diff) | |
Merge tag 'x86-urgent-2025-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"Fix a CPU topology code regression that caused the mishandling of
certain boot command line options, and re-enable CONFIG_PTDUMP on i386
that was mistakenly turned off in the Kconfig"
* tag 'x86-urgent-2025-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/topology: Implement topology_is_core_online() to address SMT regression
x86/Kconfig: Reenable PTDUMP on i386
| -rw-r--r-- | arch/x86/Kconfig | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/topology.h | 10 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/topology.c | 13 |
3 files changed, 24 insertions, 1 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 52c8910ba2ef..05880301212e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -26,7 +26,6 @@ config X86_64 depends on 64BIT # Options that are inherently 64-bit kernel only: select ARCH_HAS_GIGANTIC_PAGE - select ARCH_HAS_PTDUMP select ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS select ARCH_SUPPORTS_INT128 if CC_HAS_INT128 select ARCH_SUPPORTS_PER_VMA_LOCK @@ -99,6 +98,7 @@ config X86 select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_PMEM_API if X86_64 select ARCH_HAS_PREEMPT_LAZY + select ARCH_HAS_PTDUMP select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_HW_PTE_YOUNG select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2 diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h index 6c79ee7c0957..21041898157a 100644 --- a/arch/x86/include/asm/topology.h +++ b/arch/x86/include/asm/topology.h @@ -231,6 +231,16 @@ static inline bool topology_is_primary_thread(unsigned int cpu) } #define topology_is_primary_thread topology_is_primary_thread +int topology_get_primary_thread(unsigned int cpu); + +static inline bool topology_is_core_online(unsigned int cpu) +{ + int pcpu = topology_get_primary_thread(cpu); + + return pcpu >= 0 ? cpu_online(pcpu) : false; +} +#define topology_is_core_online topology_is_core_online + #else /* CONFIG_SMP */ static inline int topology_phys_to_logical_pkg(unsigned int pkg) { return 0; } static inline int topology_max_smt_threads(void) { return 1; } diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c index e35ccdc84910..6073a16628f9 100644 --- a/arch/x86/kernel/cpu/topology.c +++ b/arch/x86/kernel/cpu/topology.c @@ -372,6 +372,19 @@ unsigned int topology_unit_count(u32 apicid, enum x86_topology_domains which_uni return topo_unit_count(lvlid, at_level, apic_maps[which_units].map); } +#ifdef CONFIG_SMP +int topology_get_primary_thread(unsigned int cpu) +{ + u32 apic_id = cpuid_to_apicid[cpu]; + + /* + * Get the core domain level APIC id, which is the primary thread + * and return the CPU number assigned to it. + */ + return topo_lookup_cpuid(topo_apicid(apic_id, TOPO_CORE_DOMAIN)); +} +#endif + #ifdef CONFIG_ACPI_HOTPLUG_CPU /** * topology_hotplug_apic - Handle a physical hotplugged APIC after boot |