2 files changed, 18 insertions, 0 deletions

diff --git a/arch/x86/include/asm/uv/uv_hub.h b/arch/x86/include/asm/uv/uv_hub.h
index bc54fa965af3..40be813fefb1 100644
--- a/arch/x86/include/asm/uv/uv_hub.h
+++ b/arch/x86/include/asm/uv/uv_hub.h
@@ -495,5 +495,17 @@ static inline void uv_hub_send_ipi(int pnode, int apicid, int vector)
         uv_write_global_mmr64(pnode, UVH_IPI_INT, val);
 }
 
+/*
+ * Get the minimum revision number of the hub chips within the partition.
+ *     1 - initial rev 1.0 silicon
+ *     2 - rev 2.0 production silicon
+ */
+static inline int uv_get_min_hub_revision_id(void)
+{
+        extern int uv_min_hub_revision_id;
+
+        return uv_min_hub_revision_id;
+}
+
 #endif /* CONFIG_X86_64 */
 #endif /* _ASM_X86_UV_UV_HUB_H */
diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
index b8bb869a6618..0e48de9ff864 100644
--- a/arch/x86/kernel/apic/x2apic_uv_x.c
+++ b/arch/x86/kernel/apic/x2apic_uv_x.c
@@ -36,6 +36,8 @@ DEFINE_PER_CPU(int, x2apic_extra_bits);
 
 static enum uv_system_type uv_system_type;
 static u64 gru_start_paddr, gru_end_paddr;
+int uv_min_hub_revision_id;
+EXPORT_SYMBOL_GPL(uv_min_hub_revision_id);
 
 static inline bool is_GRU_range(u64 start, u64 end)
 {
@@ -55,6 +57,10 @@ static int early_get_nodeid(void)
         mmr = early_ioremap(UV_LOCAL_MMR_BASE | UVH_NODE_ID, sizeof(*mmr));
         node_id.v = *mmr;
         early_iounmap(mmr, sizeof(*mmr));
+
+        /* Currently, all blades have same revision number */
+        uv_min_hub_revision_id = node_id.s.revision;
+
         return node_id.s.node_id;
 }