From: Shiju Jose <shiju.jose@huawei.com>

In the numa_memblks, a lookup facility is required to retrieve the
physical address range of memory in a NUMA node. ACPI RAS2 memory
features are among the use cases.

Suggested-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Signed-off-by: Shiju Jose <shiju.jose@huawei.com>
---
 include/linux/numa.h         |  9 +++++++++
 include/linux/numa_memblks.h |  2 ++
 mm/numa.c                    | 10 ++++++++++
 mm/numa_memblks.c            | 37 ++++++++++++++++++++++++++++++++++++
 4 files changed, 58 insertions(+)

diff --git a/include/linux/numa.h b/include/linux/numa.h
index e6baaf6051bc..1d1aabebd26b 100644
--- a/include/linux/numa.h
+++ b/include/linux/numa.h
@@ -41,6 +41,10 @@ int memory_add_physaddr_to_nid(u64 start);
 int phys_to_target_node(u64 start);
 #endif
 
+#ifndef nid_get_mem_physaddr_range
+int nid_get_mem_physaddr_range(int nid, u64 *start, u64 *end);
+#endif
+
 int numa_fill_memblks(u64 start, u64 end);
 
 #else /* !CONFIG_NUMA */
@@ -63,6 +67,11 @@ static inline int phys_to_target_node(u64 start)
 	return 0;
 }
 
+static inline int nid_get_mem_physaddr_range(int nid, u64 *start, u64 *end)
+{
+	return 0;
+}
+
 static inline void alloc_offline_node_data(int nid) {}
 #endif
 
diff --git a/include/linux/numa_memblks.h b/include/linux/numa_memblks.h
index 991076cba7c5..7b32d96d0134 100644
--- a/include/linux/numa_memblks.h
+++ b/include/linux/numa_memblks.h
@@ -55,6 +55,8 @@ extern int phys_to_target_node(u64 start);
 #define phys_to_target_node phys_to_target_node
 extern int memory_add_physaddr_to_nid(u64 start);
 #define memory_add_physaddr_to_nid memory_add_physaddr_to_nid
+extern int nid_get_mem_physaddr_range(int nid, u64 *start, u64 *end);
+#define nid_get_mem_physaddr_range nid_get_mem_physaddr_range
 #endif /* CONFIG_NUMA_KEEP_MEMINFO */
 
 #endif /* CONFIG_NUMA_MEMBLKS */
diff --git a/mm/numa.c b/mm/numa.c
index 7d5e06fe5bd4..5335af1fefee 100644
--- a/mm/numa.c
+++ b/mm/numa.c
@@ -59,3 +59,13 @@ int phys_to_target_node(u64 start)
 }
 EXPORT_SYMBOL_GPL(phys_to_target_node);
 #endif
+
+#ifndef nid_get_mem_physaddr_range
+int nid_get_mem_physaddr_range(int nid, u64 *start, u64 *end)
+{
+	pr_info_once("Unknown target phys addr range for node=%d\n", nid);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nid_get_mem_physaddr_range);
+#endif
diff --git a/mm/numa_memblks.c b/mm/numa_memblks.c
index 541a99c4071a..e1e56b7a3499 100644
--- a/mm/numa_memblks.c
+++ b/mm/numa_memblks.c
@@ -590,4 +590,41 @@ int memory_add_physaddr_to_nid(u64 start)
 }
 EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
 
+/**
+ * nid_get_mem_physaddr_range - Get the physical address range
+ *				of the memblk in the NUMA node.
+ * @nid: NUMA node ID of the memblk
+ * @start: Start address of the memblk
+ * @end: End address of the memblk
+ *
+ * Find the lowest contiguous physical memory address range of the memblk
+ * in the NUMA node with the given nid and return the start and end
+ * addresses.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int nid_get_mem_physaddr_range(int nid, u64 *start, u64 *end)
+{
+	struct numa_meminfo *mi = &numa_meminfo;
+	int i;
+
+	if (!numa_valid_node(nid))
+		return -EINVAL;
+
+	for (i = 0; i < mi->nr_blks; i++) {
+		if (mi->blk[i].nid == nid) {
+			*start = mi->blk[i].start;
+			/*
+			 * Assumption: mi->blk[i].end is the last address
+			 * in the range + 1.
+			 */
+			*end = mi->blk[i].end;
+			return 0;
+		}
+	}
+
+	return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(nid_get_mem_physaddr_range);
 #endif /* CONFIG_NUMA_KEEP_MEMINFO */
-- 
2.43.0