powerpc/smp: smp_ops->kick_cpu() should be able to fail

When we start a cpu we use smp_ops->kick_cpu(), which currently
returns void, it should be able to fail. Convert it to return
int, and update all uses.

Convert all the current error cases to return -ENOENT, which is
what would eventually be returned by __cpu_up() currently when
it doesn't detect the cpu as coming up in time.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index cbdbb14be4b..b6083f4f39b 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -95,7 +95,7 @@ int smt_enabled_at_boot = 1;
 static void (*crash_ipi_function_ptr)(struct pt_regs *) = NULL;
 
 #ifdef CONFIG_PPC64
-void __devinit smp_generic_kick_cpu(int nr)
+int __devinit smp_generic_kick_cpu(int nr)
 {
         BUG_ON(nr < 0 || nr >= NR_CPUS);
 
@@ -106,6 +106,8 @@ void __devinit smp_generic_kick_cpu(int nr)
          */
         paca[nr].cpu_start = 1;
         smp_mb();
+
+        return 0;
 }
 #endif
 
@@ -434,7 +436,11 @@ int __cpuinit __cpu_up(unsigned int cpu)
 
         /* wake up cpus */
         DBG("smp: kicking cpu %d\n", cpu);
-        smp_ops->kick_cpu(cpu);
+        rc = smp_ops->kick_cpu(cpu);
+        if (rc) {
+                pr_err("smp: failed starting cpu %d (rc %d)\n", cpu, rc);
+                return rc;
+        }
 
         /*
          * wait to see if the cpu made a callin (is actually up).