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/

diff --git a/arch/mips/include/asm/smp-ops.h b/arch/mips/include/asm/smp-ops.h
index 9e09af3..48b03ff 100644 (file)
--- a/arch/mips/include/asm/smp-ops.h
+++ b/arch/mips/include/asm/smp-ops.h
@@ -56,8 +56,43 @@ static inline void register_smp_ops(struct plat_smp_ops *ops)
 
 #endif /* !CONFIG_SMP */
 
-extern struct plat_smp_ops up_smp_ops;
-extern struct plat_smp_ops cmp_smp_ops;
-extern struct plat_smp_ops vsmp_smp_ops;
+static inline int register_up_smp_ops(void)
+{
+#ifdef CONFIG_SMP_UP
+       extern struct plat_smp_ops up_smp_ops;
+
+       register_smp_ops(&up_smp_ops);
+
+       return 0;
+#else
+       return -ENODEV;
+#endif
+}
+
+static inline int register_cmp_smp_ops(void)
+{
+#ifdef CONFIG_MIPS_CMP
+       extern struct plat_smp_ops cmp_smp_ops;
+
+       register_smp_ops(&cmp_smp_ops);
+
+       return 0;
+#else
+       return -ENODEV;
+#endif
+}
+
+static inline int register_vsmp_smp_ops(void)
+{
+#ifdef CONFIG_MIPS_MT_SMP
+       extern struct plat_smp_ops vsmp_smp_ops;
+
+       register_smp_ops(&vsmp_smp_ops);
+
+       return 0;
+#else
+       return -ENODEV;
+#endif
+}
 
 #endif /* __ASM_SMP_OPS_H */

diff --git a/arch/mips/mipssim/sim_setup.c b/arch/mips/mipssim/sim_setup.c
index 55f22a3..1970069 100644 (file)
--- 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)

diff --git a/arch/mips/mti-malta/malta-init.c b/arch/mips/mti-malta/malta-init.c
index 31180c3..4b988b9 100644 (file)
--- a/arch/mips/mti-malta/malta-init.c
+++ b/arch/mips/mti-malta/malta-init.c
@@ -28,6 +28,7 @@
 #include <asm/io.h>
 #include <asm/system.h>
 #include <asm/cacheflush.h>
+#include <asm/smp-ops.h>
 #include <asm/traps.h>
 
 #include <asm/gcmpregs.h>
@@ -358,15 +359,14 @@ void __init prom_init(void)
 #ifdef CONFIG_SERIAL_8250_CONSOLE
        console_config();
 #endif
-#ifdef CONFIG_MIPS_CMP
        /* Early detection of CMP support */
        if (gcmp_probe(GCMP_BASE_ADDR, GCMP_ADDRSPACE_SZ))
-               register_smp_ops(&cmp_smp_ops);
-       else
-#endif
-#ifdef CONFIG_MIPS_MT_SMP
-               register_smp_ops(&vsmp_smp_ops);
-#endif
+               if (!register_cmp_smp_ops())
+                       return;
+
+       if (!register_vsmp_smp_ops())
+               return;
+
 #ifdef CONFIG_MIPS_MT_SMTC
        register_smp_ops(&msmtc_smp_ops);
 #endif

diff --git a/arch/mips/pmc-sierra/msp71xx/msp_setup.c b/arch/mips/pmc-sierra/msp71xx/msp_setup.c
index 2413ea6..0abfbe0 100644 (file)
--- a/arch/mips/pmc-sierra/msp71xx/msp_setup.c
+++ b/arch/mips/pmc-sierra/msp71xx/msp_setup.c
@@ -228,13 +228,11 @@ void __init prom_init(void)
         */
        msp_serial_setup();
 
-#ifdef CONFIG_MIPS_MT_SMP
-       register_smp_ops(&vsmp_smp_ops);
-#endif
-
+       if (register_vsmp_smp_ops()) {
 #ifdef CONFIG_MIPS_MT_SMTC
-       register_smp_ops(&msp_smtc_smp_ops);
+               register_smp_ops(&msp_smtc_smp_ops);
 #endif
+       }
 
 #ifdef CONFIG_PMCTWILED
        /*