x86/platform/UV: Fix incorrect nodes and pnodes for cpuless and memoryless nodes

This patch fixes the problem of incorrect nodes and pnodes being returned
when referring to nodes that either have no cpus (AKA "headless") or no
memory.

Tested-by: John Estabrook <estabrook@sgi.com>
Tested-by: Gary Kroening <gfk@sgi.com>
Tested-by: Nathan Zimmer <nzimmer@sgi.com>
Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <rja@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160429215406.192644884@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/apic/x2apic_uv_x.c

@@ -1232,8 +1232,7 @@ static void __init decode_uv_systab(void)
  */
 static __init void boot_init_possible_blades(struct uv_hub_info_s *hub_info)
 {
-	size_t bytes;
-	int blade, i, j, uv_pb = 0, num_nodes = num_possible_nodes();
+	int i, uv_pb = 0;
 
 	pr_info("UV: NODE_PRESENT_DEPTH = %d\n", UVH_NODE_PRESENT_TABLE_DEPTH);
 	for (i = 0; i < UVH_NODE_PRESENT_TABLE_DEPTH; i++) {
@@ -1247,28 +1246,6 @@ static __init void boot_init_possible_blades(struct uv_hub_info_s *hub_info)
 	}
 	if (uv_possible_blades != uv_pb)
 		uv_possible_blades = uv_pb;
-
-	bytes = num_nodes * sizeof(_node_to_pnode[0]);
-	_node_to_pnode = kmalloc(bytes, GFP_KERNEL);
-	BUG_ON(!_node_to_pnode);
-
-	for (blade = 0, i = 0; i < UVH_NODE_PRESENT_TABLE_DEPTH; i++) {
-		unsigned short pnode;
-		unsigned long present =
-			uv_read_local_mmr(UVH_NODE_PRESENT_TABLE + i * 8);
-
-		for (j = 0; j < 64; j++) {
-			if (!test_bit(j, &present))
-				continue;
-			pnode = (i * 64 + j) & hub_info->pnode_mask;
-			_node_to_pnode[blade++] = pnode;
-		}
-		if (blade > num_nodes) {
-			pr_err("UV: blade count(%d) exceeds node count(%d)!\n",
-				blade, num_nodes);
-			BUG();
-		}
-	}
 }
 
 static void __init build_socket_tables(void)
@@ -1449,7 +1426,6 @@ void __init uv_system_init(void)
 	bytes = sizeof(struct uv_hub_info_s);
 	for_each_node(nodeid) {
 		struct uv_hub_info_s *new_hub;
-		unsigned short pnode;
 
 		if (__uv_hub_info_list[nodeid]) {
 			pr_err("UV: Node %d UV HUB already initialized!?\n",
@@ -1467,10 +1443,11 @@ void __init uv_system_init(void)
 		BUG_ON(!new_hub);
 		*new_hub = hub_info;
 
-		pnode = _node_to_pnode[nodeid];
-		min_pnode = min(pnode, min_pnode);
-		max_pnode = max(pnode, max_pnode);
-		new_hub->pnode = pnode;
+		/* Use information from GAM table if available */
+		if (_node_to_pnode)
+			new_hub->pnode = _node_to_pnode[nodeid];
+		else	/* Fill in during cpu loop */
+			new_hub->pnode = 0xffff;
 		new_hub->numa_blade_id = uv_node_to_blade_id(nodeid);
 		new_hub->memory_nid = -1;
 		new_hub->nr_possible_cpus = 0;
@@ -1480,18 +1457,39 @@ void __init uv_system_init(void)
 	/* Initialize per cpu info */
 	for_each_possible_cpu(cpu) {
 		int apicid = per_cpu(x86_cpu_to_apicid, cpu);
+		int numa_node_id;
+		unsigned short pnode;
 
 		nodeid = cpu_to_node(cpu);
+		numa_node_id = numa_cpu_node(cpu);
+		pnode = uv_apicid_to_pnode(apicid);
+
 		uv_cpu_info_per(cpu)->p_uv_hub_info = uv_hub_info_list(nodeid);
 		uv_cpu_info_per(cpu)->blade_cpu_id =
 			uv_cpu_hub_info(cpu)->nr_possible_cpus++;
 		if (uv_cpu_hub_info(cpu)->memory_nid == -1)
 			uv_cpu_hub_info(cpu)->memory_nid = cpu_to_node(cpu);
+		if (nodeid != numa_node_id &&	/* init memoryless node */
+		    uv_hub_info_list(numa_node_id)->pnode == 0xffff)
+			uv_hub_info_list(numa_node_id)->pnode = pnode;
+		else if (uv_cpu_hub_info(cpu)->pnode == 0xffff)
+			uv_cpu_hub_info(cpu)->pnode = pnode;
 		uv_cpu_scir_info(cpu)->offset = uv_scir_offset(apicid);
 	}
 
-	/* Display per node info */
 	for_each_node(nodeid) {
+		unsigned short pnode = uv_hub_info_list(nodeid)->pnode;
+
+		/* Add pnode info for pre-GAM list nodes without cpus */
+		if (pnode == 0xffff) {
+			unsigned long paddr;
+
+			paddr = node_start_pfn(nodeid) << PAGE_SHIFT;
+			pnode = uv_gpa_to_pnode(uv_soc_phys_ram_to_gpa(paddr));
+			uv_hub_info_list(nodeid)->pnode = pnode;
+		}
+		min_pnode = min(pnode, min_pnode);
+		max_pnode = max(pnode, max_pnode);
 		pr_info("UV: UVHUB node:%2d pn:%02x nrcpus:%d\n",
 			nodeid,
 			uv_hub_info_list(nodeid)->pnode,