ARM: call machine_shutdown() from machine_halt(), etc

x86 calls machine_shutdown() from the various machine_*() calls which
take the machine down ready for halting, restarting, etc, and uses
this to bring the system safely to a point where those actions can be
performed.  Such actions are stopping the secondary CPUs.

So, change the ARM implementation of these to reflect what x86 does.

This solves kexec problems on ARM SMP platforms, where the secondary
CPUs were left running across the kexec call.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

3 files changed, 18 insertions, 9 deletions

diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
index 3b4872c2da8e..df5958f6864f 100644
--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -37,10 +37,6 @@ void machine_kexec_cleanup(struct kimage *image)
 {
 }
 
-void machine_shutdown(void)
-{
-}
-
 void machine_crash_shutdown(struct pt_regs *regs)
 {
 }
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index aaf51159203a..2e2ec97cc50c 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -198,19 +198,29 @@ int __init reboot_setup(char *str)
 
 __setup("reboot=", reboot_setup);
 
-void machine_halt(void)
+void machine_shutdown(void)
 {
+#ifdef CONFIG_SMP
+        smp_send_stop();
+#endif
 }
 
+void machine_halt(void)
+{
+        machine_shutdown();
+        while (1);
+}
 
 void machine_power_off(void)
 {
+        machine_shutdown();
         if (pm_power_off)
                 pm_power_off();
 }
 
 void machine_restart(char *cmd)
 {
+        machine_shutdown();
         arm_pm_restart(reboot_mode, cmd);
 }
 
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 0170e248a1dd..40dc74f2b27f 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -471,10 +471,13 @@ static DEFINE_SPINLOCK(stop_lock);
  */
 static void ipi_cpu_stop(unsigned int cpu)
 {
-        spin_lock(&stop_lock);
-        printk(KERN_CRIT "CPU%u: stopping\n", cpu);
-        dump_stack();
-        spin_unlock(&stop_lock);
+        if (system_state == SYSTEM_BOOTING ||
+            system_state == SYSTEM_RUNNING) {
+                spin_lock(&stop_lock);
+                printk(KERN_CRIT "CPU%u: stopping\n", cpu);
+                dump_stack();
+                spin_unlock(&stop_lock);
+        }
 
         set_cpu_online(cpu, false);