MIPS: Malta: Fix crash in SMP kernel on non-CMP systems.

Since 6be63bbbdab66b9185dc6f67c8b1bacb6f37f946 (lmo) rsp.
af3a1f6f4813907e143f87030cde67a9971db533 (kernel.org) the Malta code does
no longer probe for presence of GCMP if CMP is not configured.  This means
that the variable gcmp_present well be left at its default value of -1
which normally is meant to indicate that GCMP has not yet been mmapped.
This non-zero value is now interpreted as GCMP being present resulting
in a write attempt to a GCMP register resulting in a crash.

Reported and a build fix on top of my fix by Rob Landley <rob@landley.net>.

Reported-by: Rob Landley <rob@landley.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/2413/

1 files changed, 8 insertions, 9 deletions

diff --git a/arch/mips/mipssim/sim_setup.c b/arch/mips/mipssim/sim_setup.c
index 55f22a3afe61..19700696a847 100644
--- a/arch/mips/mipssim/sim_setup.c
+++ b/arch/mips/mipssim/sim_setup.c
@@ -59,18 +59,17 @@ void __init prom_init(void)
 
         prom_meminit();
 
-#ifdef CONFIG_MIPS_MT_SMP
-        if (cpu_has_mipsmt)
-                register_smp_ops(&vsmp_smp_ops);
-        else
-                register_smp_ops(&up_smp_ops);
-#endif
+        if (cpu_has_mipsmt) {
+                if (!register_vsmp_smp_ops())
+                        return;
+
 #ifdef CONFIG_MIPS_MT_SMTC
-        if (cpu_has_mipsmt)
                 register_smp_ops(&ssmtc_smp_ops);
-        else
-                register_smp_ops(&up_smp_ops);
+                        return;
 #endif
+        }
+
+        register_up_smp_ops();
 }
 
 static void __init serial_init(void)