The following commit has been merged into the perf/core branch of tip:

Commit-ID:     2eb2802a41a222bf8d78a88f193ce665071c869e
Gitweb:        https://git.kernel.org/tip/2eb2802a41a222bf8d78a88f193ce665071c869e
Author:        Dapeng Mi <dapeng1.mi@linux.intel.com>
AuthorDate:    Tue, 20 Aug 2024 07:38:51 
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 07 Oct 2024 09:28:43 +02:00

x86/cpu/intel: Define helper to get CPU core native ID

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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lkml.kernel.org/r/20240820073853.1974746-3-dapeng1.mi@linux.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 aa30fd8..5af69b5 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 e7656cb..624397e 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1299,3 +1299,18 @@ 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);
+}