[PATCH 04/11] cpu topology: export die_id

[Len Brown]

From: Len Brown <len.br...@intel.com>

Export die_id in cpu topology, for the benefit of hardware that
has multiple die per package.  die_id is quite similar to core_id,
in that it holds multiple CPUs, but is inside a package.

This needed by topology-aware user-space.  In particular,
an application, such as turbostat(8), which needs to know
the actual scope of "package-scope" MSRs.

Signed-off-by: Len Brown <len.br...@intel.com>
Cc: linux-...@vger.kernel.org
Signed-off-by: Len Brown <len.br...@intel.com>
---
 Documentation/cputopology.txt   | 10 ++++++++--
 arch/x86/include/asm/topology.h |  1 +
 drivers/base/topology.c         |  4 ++++
 include/linux/topology.h        |  3 +++
 4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt
index 2698da7e4f49..287213b4517b 100644
--- a/Documentation/cputopology.txt
+++ b/Documentation/cputopology.txt
@@ -12,6 +12,12 @@ physical_package_id:
        socket number, but the actual value is architecture and platform
        dependent.
 
+die_id:
+
+       the CPU die ID of cpuX. Typically it is the hardware platform's
+       identifier (rather than the kernel's).  The actual value is
+       architecture and platform dependent.
+
 core_id:
 
        the CPU core ID of cpuX. Typically it is the hardware platform's
@@ -43,12 +49,12 @@ thread_siblings_list:
 core_siblings:
 
        internal kernel map of cpuX's hardware threads within the same
-       physical_package_id.
+       die_id.
 
 core_siblings_list:
 
        human-readable list of cpuX's hardware threads within the same
-       physical_package_id.
+       die_id.
 
 book_siblings:
 
diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 453cf38a1c33..281be6bbc80d 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -106,6 +106,7 @@ extern const struct cpumask *cpu_coregroup_mask(int cpu);
 
 #define topology_logical_package_id(cpu)       (cpu_data(cpu).logical_proc_id)
 #define topology_physical_package_id(cpu)      (cpu_data(cpu).phys_proc_id)
+#define topology_die_id(cpu)                   (cpu_data(cpu).cpu_die_id)
 #define topology_core_id(cpu)                  (cpu_data(cpu).cpu_core_id)
 
 #ifdef CONFIG_SMP
diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index 5fd9f167ecc1..50352cf96f85 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -43,6 +43,9 @@ static ssize_t name##_list_show(struct device *dev,           
        \
 define_id_show_func(physical_package_id);
 static DEVICE_ATTR_RO(physical_package_id);
 
+define_id_show_func(die_id);
+static DEVICE_ATTR_RO(die_id);
+
 define_id_show_func(core_id);
 static DEVICE_ATTR_RO(core_id);
 
@@ -72,6 +75,7 @@ static DEVICE_ATTR_RO(drawer_siblings_list);
 
 static struct attribute *default_attrs[] = {
        &dev_attr_physical_package_id.attr,
+       &dev_attr_die_id.attr,
        &dev_attr_core_id.attr,
        &dev_attr_thread_siblings.attr,
        &dev_attr_thread_siblings_list.attr,
diff --git a/include/linux/topology.h b/include/linux/topology.h
index cb0775e1ee4b..5cc8595dd0e4 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -184,6 +184,9 @@ static inline int cpu_to_mem(int cpu)
 #ifndef topology_physical_package_id
 #define topology_physical_package_id(cpu)      ((void)(cpu), -1)
 #endif
+#ifndef topology_die_id
+#define topology_die_id(cpu)                   ((void)(cpu), -1)
+#endif
 #ifndef topology_core_id
 #define topology_core_id(cpu)                  ((void)(cpu), 0)
 #endif
-- 
2.18.0-rc0