x86/platform/uv: Setup UV functions for Hubless UV Systems

Add more support for UV systems that do not contain a UV Hub (AKA
"hubless").  This update adds support for additional functions required:

    Use PCH NMI handler instead of a UV Hub NMI handler.

    Initialize the UV BIOS callback interface used to support specific
    UV functions.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hedi Berriche <hedi.berriche@hpe.com>
Cc: Justin Ernst <justin.ernst@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russ Anderson <russ.anderson@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190910145839.975787119@stormcage.eag.rdlabs.hpecorp.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/apic/x2apic_uv_x.c

@@ -1457,6 +1457,20 @@ static void __init build_socket_tables(void)
 	}
 }
 
+/* Initialize UV hubless systems */
+static __init int uv_system_init_hubless(void)
+{
+	int rc;
+
+	/* Setup PCH NMI handler */
+	uv_nmi_setup_hubless();
+
+	/* Init kernel/BIOS interface */
+	rc = uv_bios_init();
+
+	return rc;
+}
+
 static void __init uv_system_init_hub(void)
 {
 	struct uv_hub_info_s hub_info = {0};
@@ -1596,8 +1610,8 @@ static void __init uv_system_init_hub(void)
 }
 
 /*
- * There is a small amount of UV specific code needed to initialize a
- * UV system that does not have a "UV HUB" (referred to as "hubless").
+ * There is a different code path needed to initialize a UV system that does
+ * not have a "UV HUB" (referred to as "hubless").
  */
 void __init uv_system_init(void)
 {
@@ -1607,7 +1621,7 @@ void __init uv_system_init(void)
 	if (is_uv_system())
 		uv_system_init_hub();
 	else
-		uv_nmi_setup_hubless();
+		uv_system_init_hubless();
 }
 
 apic_driver(apic_x2apic_uv_x);