[PATCH v4 01/11] x86/topology: Introduce topology_logical_core_id()

Dhananjay Ugwekar
2024-07-11T10:27:10Z

From: K Prateek Nayak <kprateek.nayak@amd.com>

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 per-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>
Reviewed-by: Zhang Rui <rui.zhang@intel.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 7352ab89a55a..c12837e61bda 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 cb4f6c513c48..1ffe4260bef6 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 abe3a8f22cbd..2a6dbf965d92 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -137,6 +137,7 @@ 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 3baf3e435834..b1eb6d7828db 100644
--- a/arch/x86/kernel/cpu/debugfs.c
+++ b/arch/x86/kernel/cpu/debugfs.c
@@ -24,6 +24,7 @@ static int cpu_debug_show(struct seq_file *m, void *p)
seq_printf(m, "core_id: %u\n", c->topo.core_id);
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 9a6069e7133c..23722aa21e2f 100644
--- a/arch/x86/kernel/cpu/topology_common.c
+++ b/arch/x86/kernel/cpu/topology_common.c
@@ -151,6 +151,7 @@ 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 */
--
2.34.1