[PATCH] ppc64: Fix UP kernel build

CONFIG_KEXEC breaks UP builds because of a misspelled smp_release_cpus().
Also, the function isn't defined unless built with CONFIG_SMP but it is
needed if we are to go from a UP to SMP kernel.  Enable it and document it.

Thanks to Steven Winiecki for reporting this and to Milton for remembering
how it's supposed to work and why.

Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 6 insertions, 2 deletions

diff --git a/arch/ppc64/kernel/head.S b/arch/ppc64/kernel/head.S
index 74fc3bc6860..784f56d4684 100644
--- a/arch/ppc64/kernel/head.S
+++ b/arch/ppc64/kernel/head.S
@@ -2071,7 +2071,7 @@ _GLOBAL(hmt_start_secondary)
         blr
 #endif
 
-#if defined(CONFIG_SMP) && !defined(CONFIG_PPC_ISERIES)
+#if defined(CONFIG_KEXEC) || (defined(CONFIG_SMP) && !defined(CONFIG_PPC_ISERIES))
 _GLOBAL(smp_release_cpus)
         /* All secondary cpus are spinning on a common
          * spinloop, release them all now so they can start
diff --git a/arch/ppc64/kernel/machine_kexec.c b/arch/ppc64/kernel/machine_kexec.c
index fdb2fc649d7..5c40bb6788d 100644
--- a/arch/ppc64/kernel/machine_kexec.c
+++ b/arch/ppc64/kernel/machine_kexec.c
@@ -243,13 +243,17 @@ static void kexec_prepare_cpus(void)
 
 static void kexec_prepare_cpus(void)
 {
+        extern void smp_release_cpus(void);
         /*
          * move the secondarys to us so that we can copy
          * the new kernel 0-0x100 safely
          *
          * do this if kexec in setup.c ?
+         *
+         * We need to release the cpus if we are ever going from an
+         * UP to an SMP kernel.
          */
-        smp_relase_cpus();
+        smp_release_cpus();
         if (ppc_md.cpu_irq_down)
                 ppc_md.cpu_irq_down();
         local_irq_disable();