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x86/cpu/topology: Retrieve cores per package from topology bitmaps

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Similar to other sizing information the number of cores per package can be
established from the topology bitmap.

Provide a function for retrieving that information and replace the buggy
hack in the CPUID evaluation with it.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20240213210252.956858282@linutronix.de
This commit is contained in:
Thomas Gleixner 2024-02-13 22:06:10 +01:00
parent 380414be78
commit 3205c9833d
3 changed files with 57 additions and 15 deletions
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43
arch/x86/kernel/cpu/topology.c
View File

@ -257,6 +257,49 @@ int topology_get_logical_id(u32 apicid, enum x86_topology_domains at_level)
}
EXPORT_SYMBOL_GPL(topology_get_logical_id);
/**
* topology_unit_count - Retrieve the count of specified units at a given topology domain level
* @apicid: The APIC ID which specifies the search range
* @which_units: The domain level specifying the units to count
* @at_level: The domain level at which @which_units have to be counted
*
* This returns the number of possible units according to the enumerated
* information.
*
* E.g. topology_count_units(apicid, TOPO_CORE_DOMAIN, TOPO_PKG_DOMAIN)
* counts the number of possible cores in the package to which @apicid
* belongs.
*
* @at_level must obviously be greater than @which_level to produce useful
* results. If @at_level is equal to @which_units the result is
* unsurprisingly 1. If @at_level is less than @which_units the results
* is by definition undefined and the function returns 0.
*/
unsigned int topology_unit_count(u32 apicid, enum x86_topology_domains which_units,
enum x86_topology_domains at_level)
{
/* Remove the bits below @at_level to get the proper level ID of @apicid */
unsigned int lvlid = topo_apicid(apicid, at_level);
unsigned int id, end, cnt = 0;
if (lvlid >= MAX_LOCAL_APIC)
return 0;
if (!test_bit(lvlid, apic_maps[at_level].map))
return 0;
if (which_units > at_level)
return 0;
if (which_units == at_level)
return 1;
/* Calculate the exclusive end */
end = lvlid + (1U << x86_topo_system.dom_shifts[at_level]);
/* Unfortunately there is no bitmap_weight_range() */
for (id = find_next_bit(apic_maps[which_units].map, end, lvlid);
id < end; id = find_next_bit(apic_maps[which_units].map, end, ++id))
cnt++;
return cnt;
}
#ifdef CONFIG_ACPI_HOTPLUG_CPU
/**
* topology_hotplug_apic - Handle a physical hotplugged APIC after boot

11
arch/x86/kernel/cpu/topology.h
View File

@ -53,4 +53,15 @@ static inline void topology_update_dom(struct topo_scan *tscan, enum x86_topolog
tscan->dom_ncpus[dom] = ncpus;
}
#ifdef CONFIG_X86_LOCAL_APIC
unsigned int topology_unit_count(u32 apicid, enum x86_topology_domains which_units,
enum x86_topology_domains at_level);
#else
static inline unsigned int topology_unit_count(u32 apicid, enum x86_topology_domains which_units,
enum x86_topology_domains at_level)
{
return 1;
}
#endif
#endif /* ARCH_X86_TOPOLOGY_H */

18
arch/x86/kernel/cpu/topology_common.c
View File

@ -155,25 +155,15 @@ static void topo_set_ids(struct topo_scan *tscan)
c->topo.core_id = (apicid & topo_domain_mask(TOPO_PKG_DOMAIN)) >>
x86_topo_system.dom_shifts[TOPO_SMT_DOMAIN];
/* Maximum number of cores on this package */
c->x86_max_cores = topology_unit_count(apicid, TOPO_CORE_DOMAIN, TOPO_PKG_DOMAIN);
c->topo.amd_node_id = tscan->amd_node_id;
if (c->x86_vendor == X86_VENDOR_AMD)
cpu_topology_fixup_amd(tscan);
}
static void topo_set_max_cores(struct topo_scan *tscan)
{
/*
* Bug compatible for now. This is broken on hybrid systems:
* 8 cores SMT + 8 cores w/o SMT
* tscan.dom_ncpus[TOPO_DIEGRP_DOMAIN] = 24; 24 / 2 = 12 !!
*
* Cannot be fixed without further topology enumeration changes.
*/
tscan->c->x86_max_cores = tscan->dom_ncpus[TOPO_DIEGRP_DOMAIN] >>
x86_topo_system.dom_shifts[TOPO_SMT_DOMAIN];
}
void cpu_parse_topology(struct cpuinfo_x86 *c)
{
unsigned int dom, cpu = smp_processor_id();
@ -201,7 +191,6 @@ void cpu_parse_topology(struct cpuinfo_x86 *c)
}
topo_set_ids(&tscan);
topo_set_max_cores(&tscan);
}
void __init cpu_init_topology(struct cpuinfo_x86 *c)
@ -223,7 +212,6 @@ void __init cpu_init_topology(struct cpuinfo_x86 *c)
}
topo_set_ids(&tscan);
topo_set_max_cores(&tscan);
/*
* AMD systems have Nodes per package which cannot be mapped to