[PATCH 2/4] x86/cpu/intel: Define helper to get CPU core native ID

Dapeng Mi
2024-08-08T07:47:58Z

Define helper get_this_hybrid_cpu_native_id() to return the CPU core
native ID. This core native ID combining with core type can be used to
figure out the CPU core uarch uniquely.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
---
arch/x86/include/asm/cpu.h | 6 ++++++
arch/x86/kernel/cpu/intel.c | 15 +++++++++++++++
2 files changed, 21 insertions(+)

diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index aa30fd8cad7f..5af69b5be2fb 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -32,6 +32,7 @@ extern bool handle_user_split_lock(struct pt_regs *regs, long error_code);
extern bool handle_guest_split_lock(unsigned long ip);
extern void handle_bus_lock(struct pt_regs *regs);
u8 get_this_hybrid_cpu_type(void);
+u32 get_this_hybrid_cpu_native_id(void);
#else
static inline void __init sld_setup(struct cpuinfo_x86 *c) {}
static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code)
@@ -50,6 +51,11 @@ static inline u8 get_this_hybrid_cpu_type(void)
{
return 0;
}
+
+static inline u32 get_this_hybrid_cpu_native_id(void)
+{
+ return 0;
+}
#endif
#ifdef CONFIG_IA32_FEAT_CTL
void init_ia32_feat_ctl(struct cpuinfo_x86 *c);
diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index 08b95a35b5cb..dbc457626207 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1297,3 +1297,18 @@ u8 get_this_hybrid_cpu_type(void)

return cpuid_eax(0x0000001a) >> X86_HYBRID_CPU_TYPE_ID_SHIFT;
}
+
+/**
+ * get_this_hybrid_cpu_native_id() - Get the native id of this hybrid CPU
+ *
+ * Returns the uarch native ID [23:0] of a CPU in a hybrid processor.
+ * If the processor is not hybrid, returns 0.
+ */
+u32 get_this_hybrid_cpu_native_id(void)
+{
+ if (!cpu_feature_enabled(X86_FEATURE_HYBRID_CPU))
+ return 0;
+
+ return cpuid_eax(0x0000001a) &
+ (BIT_ULL(X86_HYBRID_CPU_TYPE_ID_SHIFT) - 1);
+}
--
2.40.1