3 files changed, 28 insertions, 43 deletions

diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt
index b61cb9564023..bd699da24666 100644
--- a/Documentation/cputopology.txt
+++ b/Documentation/cputopology.txt
@@ -14,9 +14,8 @@ represent the thread siblings to cpu X in the same physical package;
 To implement it in an architecture-neutral way, a new source file,
 drivers/base/topology.c, is to export the 4 attributes.
 
-If one architecture wants to support this feature, it just needs to
-implement 4 defines, typically in file include/asm-XXX/topology.h.
-The 4 defines are:
+For an architecture to support this feature, it must define some of
+these macros in include/asm-XXX/topology.h:
 #define topology_physical_package_id(cpu)
 #define topology_core_id(cpu)
 #define topology_thread_siblings(cpu)
@@ -25,17 +24,10 @@ The 4 defines are:
 The type of **_id is int.
 The type of siblings is cpumask_t.
 
-To be consistent on all architectures, the 4 attributes should have
-default values if their values are unavailable. Below is the rule.
-1) physical_package_id: If cpu has no physical package id, -1 is the
-default value.
-2) core_id: If cpu doesn't support multi-core, its core id is 0.
-3) thread_siblings: Just include itself, if the cpu doesn't support
-HT/multi-thread.
-4) core_siblings: Just include itself, if the cpu doesn't support
-multi-core and HT/Multi-thread.
-
-So be careful when declaring the 4 defines in include/asm-XXX/topology.h.
-
-If an attribute isn't defined on an architecture, it won't be exported.
-
+To be consistent on all architectures, include/linux/topology.h
+provides default definitions for any of the above macros that are
+not defined by include/asm-XXX/topology.h:
+1) physical_package_id: -1
+2) core_id: 0
+3) thread_siblings: just the given CPU
+4) core_siblings: just the given CPU
diff --git a/drivers/base/topology.c b/drivers/base/topology.c
index 1efe162e16d7..3f6d9b0a6abe 100644
--- a/drivers/base/topology.c
+++ b/drivers/base/topology.c
@@ -93,47 +93,27 @@ static ssize_t show_##name##_list(struct sys_device *dev, char *buf) \
 #define define_siblings_show_func(name)         \
         define_siblings_show_map(name); define_siblings_show_list(name)
 
-#ifdef  topology_physical_package_id
 define_id_show_func(physical_package_id);
 define_one_ro(physical_package_id);
-#define ref_physical_package_id_attr    &attr_physical_package_id.attr,
-#else
-#define ref_physical_package_id_attr
-#endif
 
-#ifdef topology_core_id
 define_id_show_func(core_id);
 define_one_ro(core_id);
-#define ref_core_id_attr                &attr_core_id.attr,
-#else
-#define ref_core_id_attr
-#endif
 
-#ifdef topology_thread_siblings
 define_siblings_show_func(thread_siblings);
 define_one_ro(thread_siblings);
 define_one_ro(thread_siblings_list);
-#define ref_thread_siblings_attr        \
-                &attr_thread_siblings.attr, &attr_thread_siblings_list.attr,
-#else
-#define ref_thread_siblings_attr
-#endif
 
-#ifdef topology_core_siblings
 define_siblings_show_func(core_siblings);
 define_one_ro(core_siblings);
 define_one_ro(core_siblings_list);
-#define ref_core_siblings_attr          \
-                &attr_core_siblings.attr, &attr_core_siblings_list.attr,
-#else
-#define ref_core_siblings_attr
-#endif
 
 static struct attribute *default_attrs[] = {
-        ref_physical_package_id_attr
-        ref_core_id_attr
-        ref_thread_siblings_attr
-        ref_core_siblings_attr
+        &attr_physical_package_id.attr,
+        &attr_core_id.attr,
+        &attr_thread_siblings.attr,
+        &attr_thread_siblings_list.attr,
+        &attr_core_siblings.attr,
+        &attr_core_siblings_list.attr,
         NULL
 };
 
diff --git a/include/linux/topology.h b/include/linux/topology.h
index 24f3d2282e11..2158fc0d5a56 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -179,4 +179,17 @@ void arch_update_cpu_topology(void);
 #endif
 #endif /* CONFIG_NUMA */
 
+#ifndef topology_physical_package_id
+#define topology_physical_package_id(cpu)       ((void)(cpu), -1)
+#endif
+#ifndef topology_core_id
+#define topology_core_id(cpu)                   ((void)(cpu), 0)
+#endif
+#ifndef topology_thread_siblings
+#define topology_thread_siblings(cpu)           cpumask_of_cpu(cpu)
+#endif
+#ifndef topology_core_siblings
+#define topology_core_siblings(cpu)             cpumask_of_cpu(cpu)
+#endif
+
 #endif /* _LINUX_TOPOLOGY_H */