powerpc: Get merged kernel to compile and run on 32-bit SMP powermac.

This updates the powermac SMP code to use the mpic driver instead of
the openpic driver and fixes the SMP-dependent context switch code.
We had a subtle bug where we were using interrupt numbers 256-259 for
IPIs, but ppc32 had NR_IRQS = 256.  Moved the IPIs down to use interrupt
numbers 252-255 instead.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 12 insertions, 5 deletions

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index e3946769dd8e..ae316e9ed581 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -272,11 +272,6 @@ struct task_struct *__switch_to(struct task_struct *prev,
          */
         if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
                 giveup_altivec(prev);
-        /* Avoid the trap.  On smp this this never happens since
-         * we don't set last_task_used_altivec -- Cort
-         */
-        if (new->thread.regs && last_task_used_altivec == new)
-                new->thread.regs->msr |= MSR_VEC;
 #endif /* CONFIG_ALTIVEC */
 #ifdef CONFIG_SPE
         /*
@@ -288,12 +283,24 @@ struct task_struct *__switch_to(struct task_struct *prev,
          */
         if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
                 giveup_spe(prev);
+#endif /* CONFIG_SPE */
+
+#else  /* CONFIG_SMP */
+#ifdef CONFIG_ALTIVEC
+        /* Avoid the trap.  On smp this this never happens since
+         * we don't set last_task_used_altivec -- Cort
+         */
+        if (new->thread.regs && last_task_used_altivec == new)
+                new->thread.regs->msr |= MSR_VEC;
+#endif /* CONFIG_ALTIVEC */
+#ifdef CONFIG_SPE
         /* Avoid the trap.  On smp this this never happens since
          * we don't set last_task_used_spe
          */
         if (new->thread.regs && last_task_used_spe == new)
                 new->thread.regs->msr |= MSR_SPE;
 #endif /* CONFIG_SPE */
+
 #endif /* CONFIG_SMP */
 
 #ifdef CONFIG_PPC64     /* for now */