x86/platform/uv: Save OEM_ID from ACPI MADT probe

Save the OEM_ID and OEM_TABLE_ID passed to the apic driver probe function
for later use.  Also, convert the char list arg passed from the kernel
to a true null-terminated string.
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/20190910145839.732237241@stormcage.eag.rdlabs.hpecorp.netSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/apic/x2apic_uv_x.c

@@ -14,6 +14,7 @@
 #include <linux/memory.h>
 #include <linux/export.h>
 #include <linux/pci.h>
+#include <linux/acpi.h>
 
 #include <asm/e820/api.h>
 #include <asm/uv/uv_mmrs.h>
@@ -31,6 +32,10 @@ static u64			gru_dist_base, gru_first_node_paddr = -1LL, gru_last_node_paddr;
 static u64			gru_dist_lmask, gru_dist_umask;
 static union uvh_apicid		uvh_apicid;
 
+/* Unpack OEM/TABLE ID's to be NULL terminated strings */
+static u8 oem_id[ACPI_OEM_ID_SIZE + 1];
+static u8 oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
+
 /* Information derived from CPUID: */
 static struct {
 	unsigned int apicid_shift;
@@ -248,11 +253,20 @@ static void __init uv_set_apicid_hibit(void)
 	}
 }
 
-static int __init uv_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
+static void __init uv_stringify(int len, char *to, char *from)
+{
+	/* Relies on 'to' being NULL chars so result will be NULL terminated */
+	strncpy(to, from, len-1);
+}
+
+static int __init uv_acpi_madt_oem_check(char *_oem_id, char *_oem_table_id)
 {
 	int pnodeid;
 	int uv_apic;
 
+	uv_stringify(sizeof(oem_id), oem_id, _oem_id);
+	uv_stringify(sizeof(oem_table_id), oem_table_id, _oem_table_id);
+
 	if (strncmp(oem_id, "SGI", 3) != 0) {
 		if (strncmp(oem_id, "NSGI", 4) == 0) {
 			uv_hubless_system = true;