x86: call machine_shutdown and stop all CPUs in native_machine_halt

Impact: really halt all CPUs on halt

Function machine_halt (resp. native_machine_halt) is empty for x86
architectures. When command 'halt -f' is invoked, the message "System
halted." is displayed but this is not really true because all CPUs are
still running.

There are also similar inconsistencies for other arches (some uses
power-off for halt or forever-loop with IRQs enabled/disabled).

IMO there should be used the same approach for all architectures OR
what does the message "System halted" really mean?

This patch fixes it for x86.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c622772744d8..a4da7c4b3129 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -8,6 +8,7 @@
 #include <linux/pm.h>
 #include <linux/clockchips.h>
 #include <asm/system.h>
+#include <asm/apic.h>
 
 unsigned long idle_halt;
 EXPORT_SYMBOL(idle_halt);
@@ -122,6 +123,21 @@ void default_idle(void)
 EXPORT_SYMBOL(default_idle);
 #endif
 
+void stop_this_cpu(void *dummy)
+{
+        local_irq_disable();
+        /*
+         * Remove this CPU:
+         */
+        cpu_clear(smp_processor_id(), cpu_online_map);
+        disable_local_APIC();
+
+        for (;;) {
+                if (hlt_works(smp_processor_id()))
+                        halt();
+        }
+}
+
 static void do_nothing(void *unused)
 {
 }