[patch V2 33/38] x86/topology: Store extended topology leaf information

Thomas Gleixner tglx at linutronix.de
Thu May 4 12:02:51 PDT 2023


From: Thomas Gleixner <tglx at linutronix.de>

Save the extended topology leaf number if it exists and is valid in
preparation of parallel CPU bringup.

Signed-off-by: Thomas Gleixner <tglx at linutronix.de>

---
 arch/x86/include/asm/topology.h |    1 +
 arch/x86/kernel/cpu/topology.c  |    3 +++
 2 files changed, 4 insertions(+)
---
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -121,6 +121,7 @@ extern unsigned int __max_die_per_packag
 #define topology_core_cpumask(cpu)		(per_cpu(cpu_core_map, cpu))
 #define topology_sibling_cpumask(cpu)		(per_cpu(cpu_sibling_map, cpu))
 
+extern unsigned int topology_extended_leaf;
 extern unsigned int __max_logical_packages;
 #define topology_max_packages()			(__max_logical_packages)
 
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -29,6 +29,8 @@ unsigned int __max_die_per_package __rea
 EXPORT_SYMBOL(__max_die_per_package);
 
 #ifdef CONFIG_SMP
+unsigned int topology_extended_leaf __read_mostly;
+
 /*
  * Check if given CPUID extended topology "leaf" is implemented
  */
@@ -72,6 +74,7 @@ int detect_extended_topology_early(struc
 	if (leaf < 0)
 		return -1;
 
+	topology_extended_leaf = leaf;
 	set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);
 
 	cpuid_count(leaf, SMT_LEVEL, &eax, &ebx, &ecx, &edx);




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