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x86/topology: Add TOPO_CPU_TYPE_LOW_POWER

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AMD heterogeneous parts report a third core type via CPUID Fn0x80000026
EBX[31:28] (Extended CPU Topology, Core Type):

  0 - Performance
  1 - Efficiency
  2 - Low Power

get_topology_cpu_type() only translates the first two, so on parts that ship
low-power cores the third type falls through to TOPO_CPU_TYPE_UNKNOWN.

Add TOPO_CPU_TYPE_LOW_POWER which takes care of this new type.

  [ bp: Massage commit message, zap the "what" explanation. ]

Signed-off-by: Vishal Badole <Vishal.Badole@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://patch.msgid.link/20260721154514.2506972-4-Vishal.Badole@amd.com
This commit is contained in:
Vishal Badole 2026-07-21 21:15:14 +05:30 committed by Borislav Petkov (AMD)
parent bdb1b1f03b
commit 924be9d673
3 changed files with 6 additions and 1 deletions
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1
arch/x86/include/asm/processor.h
View File

@ -73,6 +73,7 @@ enum x86_topology_cpu_type {
TOPO_CPU_TYPE_ANY = 0,
TOPO_CPU_TYPE_PERFORMANCE,
TOPO_CPU_TYPE_EFFICIENCY,
TOPO_CPU_TYPE_LOW_POWER,
TOPO_CPU_TYPE_UNKNOWN,
};

3
arch/x86/kernel/acpi/cppc.c
View File

@ -281,8 +281,9 @@ int amd_get_boost_ratio_numerator(unsigned int cpu, u64 *numerator)
/* use the max scale for performance cores */
*numerator = CPPC_HIGHEST_PERF_PERFORMANCE;
return 0;
case TOPO_CPU_TYPE_LOW_POWER:
case TOPO_CPU_TYPE_EFFICIENCY:
/* use the highest perf value for efficiency cores */
/* use the highest perf value for efficiency and low-power cores */
ret = amd_get_highest_perf(cpu, &tmp);
if (ret)
return ret;

3
arch/x86/kernel/cpu/topology_common.c
View File

@ -44,6 +44,7 @@ enum x86_topology_cpu_type get_topology_cpu_type(struct cpuinfo_x86 *c)
switch (c->topo.amd_type) {
case AMD_CPU_TYPE_PERFORMANCE: return TOPO_CPU_TYPE_PERFORMANCE;
case AMD_CPU_TYPE_EFFICIENCY: return TOPO_CPU_TYPE_EFFICIENCY;
case AMD_CPU_TYPE_LOW_POWER: return TOPO_CPU_TYPE_LOW_POWER;
}
}
@ -57,6 +58,8 @@ const char *get_topology_cpu_type_name(struct cpuinfo_x86 *c)
return "performance";
case TOPO_CPU_TYPE_EFFICIENCY:
return "efficiency";
case TOPO_CPU_TYPE_LOW_POWER:
return "low_power";
default:
return "unknown";
}