Commit d4df1748 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 083fc6d7 2066f00e

arch/x86/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/x86/include/asm/topology.h

+10 −0
Original line number Diff line number Diff line
@@ -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; }

arch/x86/kernel/cpu/topology.c

+13 −0
Original line number Diff line number Diff line
@@ -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