summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/process.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/process.c')
-rw-r--r--arch/x86/kernel/process.c28
1 files changed, 27 insertions, 1 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 7dceea947232..4d629c62f4f8 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -7,6 +7,12 @@
#include <linux/module.h>
#include <linux/pm.h>
#include <linux/clockchips.h>
+#include <asm/system.h>
+
+unsigned long idle_halt;
+EXPORT_SYMBOL(idle_halt);
+unsigned long idle_nomwait;
+EXPORT_SYMBOL(idle_nomwait);
struct kmem_cache *task_xstate_cachep;
@@ -325,7 +331,27 @@ static int __init idle_setup(char *str)
pm_idle = poll_idle;
} else if (!strcmp(str, "mwait"))
force_mwait = 1;
- else
+ else if (!strcmp(str, "halt")) {
+ /*
+ * When the boot option of idle=halt is added, halt is
+ * forced to be used for CPU idle. In such case CPU C2/C3
+ * won't be used again.
+ * To continue to load the CPU idle driver, don't touch
+ * the boot_option_idle_override.
+ */
+ pm_idle = default_idle;
+ idle_halt = 1;
+ return 0;
+ } else if (!strcmp(str, "nomwait")) {
+ /*
+ * If the boot option of "idle=nomwait" is added,
+ * it means that mwait will be disabled for CPU C2/C3
+ * states. In such case it won't touch the variable
+ * of boot_option_idle_override.
+ */
+ idle_nomwait = 1;
+ return 0;
+ } else
return -1;
boot_option_idle_override = 1;