[tip: perf/core] x86/topology: Introduce topology_logical_core_id()

["tip-bot2 for K Prateek Nayak" <tip-bot2@linutronix.de>]

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

Commit-ID:     e4b444347795a1ecc083895582bc2e7f288a22e4
Gitweb:        https://git.kernel.org/tip/e4b444347795a1ecc083895582bc2e7f288a22e4
Author:        K Prateek Nayak <kprateek.nayak@amd.com>
AuthorDate:    Fri, 15 Nov 2024 06:07:58 
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 02 Dec 2024 12:01:35 +01:00

x86/topology: Introduce topology_logical_core_id()

On x86, topology_core_id() returns a unique core ID within the PKG
domain. Looking at match_smt() suggests that a core ID just needs to be
unique within a LLC domain. For use cases such as the core RAPL PMU,
there exists a need for a unique core ID across the entire system with
multiple PKG domains. Introduce topology_logical_core_id() to derive a
unique core ID across the system.

Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Dhananjay Ugwekar <Dhananjay.Ugwekar@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: "Gautham R. Shenoy" <gautham.shenoy@amd.com>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Link: https://lore.kernel.org/r/20241115060805.447565-3-Dhananjay.Ugwekar@amd.com
---
 Documentation/arch/x86/topology.rst   | 4 ++++
 arch/x86/include/asm/processor.h      | 1 +
 arch/x86/include/asm/topology.h       | 1 +
 arch/x86/kernel/cpu/debugfs.c         | 1 +
 arch/x86/kernel/cpu/topology_common.c | 1 +
 5 files changed, 8 insertions(+)

diff --git a/Documentation/arch/x86/topology.rst b/Documentation/arch/x86/topology.rst
index 7352ab8..c12837e 100644
--- a/Documentation/arch/x86/topology.rst
+++ b/Documentation/arch/x86/topology.rst
@@ -135,6 +135,10 @@ Thread-related topology information in the kernel:
     The ID of the core to which a thread belongs. It is also printed in /proc/cpuinfo
     "core_id."
 
+  - topology_logical_core_id();
+
+    The logical core ID to which a thread belongs.
+
 
 
 System topology examples
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index c097581..cfd8a55 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -98,6 +98,7 @@ struct cpuinfo_topology {
 	// Logical ID mappings
 	u32			logical_pkg_id;
 	u32			logical_die_id;
+	u32			logical_core_id;
 
 	// AMD Node ID and Nodes per Package info
 	u32			amd_node_id;
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index fd41103..3973cb9 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -143,6 +143,7 @@ extern const struct cpumask *cpu_clustergroup_mask(int cpu);
 #define topology_logical_package_id(cpu)	(cpu_data(cpu).topo.logical_pkg_id)
 #define topology_physical_package_id(cpu)	(cpu_data(cpu).topo.pkg_id)
 #define topology_logical_die_id(cpu)		(cpu_data(cpu).topo.logical_die_id)
+#define topology_logical_core_id(cpu)		(cpu_data(cpu).topo.logical_core_id)
 #define topology_die_id(cpu)			(cpu_data(cpu).topo.die_id)
 #define topology_core_id(cpu)			(cpu_data(cpu).topo.core_id)
 #define topology_ppin(cpu)			(cpu_data(cpu).ppin)
diff --git a/arch/x86/kernel/cpu/debugfs.c b/arch/x86/kernel/cpu/debugfs.c
index 10719ab..cacfd3f 100644
--- a/arch/x86/kernel/cpu/debugfs.c
+++ b/arch/x86/kernel/cpu/debugfs.c
@@ -25,6 +25,7 @@ static int cpu_debug_show(struct seq_file *m, void *p)
 	seq_printf(m, "cpu_type:            %s\n", get_topology_cpu_type_name(c));
 	seq_printf(m, "logical_pkg_id:      %u\n", c->topo.logical_pkg_id);
 	seq_printf(m, "logical_die_id:      %u\n", c->topo.logical_die_id);
+	seq_printf(m, "logical_core_id:     %u\n", c->topo.logical_core_id);
 	seq_printf(m, "llc_id:              %u\n", c->topo.llc_id);
 	seq_printf(m, "l2c_id:              %u\n", c->topo.l2c_id);
 	seq_printf(m, "amd_node_id:         %u\n", c->topo.amd_node_id);
diff --git a/arch/x86/kernel/cpu/topology_common.c b/arch/x86/kernel/cpu/topology_common.c
index 8277c64..b5a5e14 100644
--- a/arch/x86/kernel/cpu/topology_common.c
+++ b/arch/x86/kernel/cpu/topology_common.c
@@ -185,6 +185,7 @@ static void topo_set_ids(struct topo_scan *tscan, bool early)
 	if (!early) {
 		c->topo.logical_pkg_id = topology_get_logical_id(apicid, TOPO_PKG_DOMAIN);
 		c->topo.logical_die_id = topology_get_logical_id(apicid, TOPO_DIE_DOMAIN);
+		c->topo.logical_core_id = topology_get_logical_id(apicid, TOPO_CORE_DOMAIN);
 	}
 
 	/* Package relative core ID */