ia64: Use generic idle loop

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Link: http://lkml.kernel.org/r/20130321215234.406851909@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

4 files changed, 23 insertions, 72 deletions

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 9a02f71c6b1f..e0b39c3cb789 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -35,6 +35,7 @@ config IA64
         select ARCH_HAVE_NMI_SAFE_CMPXCHG
         select GENERIC_IOMAP
         select GENERIC_SMP_IDLE_THREAD
+        select GENERIC_IDLE_LOOP
         select ARCH_INIT_TASK
         select ARCH_TASK_STRUCT_ALLOCATOR
         select ARCH_THREAD_INFO_ALLOCATOR
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 2eda28414abb..9ea25fce06d5 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -42,6 +42,7 @@
 #include <linux/completion.h>
 #include <linux/tracehook.h>
 #include <linux/slab.h>
+#include <linux/cpu.h>
 
 #include <asm/errno.h>
 #include <asm/intrinsics.h>
@@ -1322,8 +1323,6 @@ out:
 }
 EXPORT_SYMBOL(pfm_unregister_buffer_fmt);
 
-extern void update_pal_halt_status(int);
-
 static int
 pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
 {
@@ -1371,9 +1370,9 @@ pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
                 cpu));
 
         /*
-         * disable default_idle() to go to PAL_HALT
+         * Force idle() into poll mode
          */
-        update_pal_halt_status(0);
+        cpu_idle_poll_ctrl(true);
 
         UNLOCK_PFS(flags);
 
@@ -1430,11 +1429,8 @@ pfm_unreserve_session(pfm_context_t *ctx, int is_syswide, unsigned int cpu)
                 is_syswide,
                 cpu));
 
-        /*
-         * if possible, enable default_idle() to go into PAL_HALT
-         */
-        if (pfm_sessions.pfs_task_sessions == 0 && pfm_sessions.pfs_sys_sessions == 0)
-                update_pal_halt_status(1);
+        /* Undo forced polling. Last session reenables pal_halt */
+        cpu_idle_poll_ctrl(false);
 
         UNLOCK_PFS(flags);
 
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 6f7dc8b7b35c..a26fc640e4ce 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -209,41 +209,13 @@ do_notify_resume_user(sigset_t *unused, struct sigscratch *scr, long in_syscall)
         local_irq_disable();    /* force interrupt disable */
 }
 
-static int pal_halt        = 1;
-static int can_do_pal_halt = 1;
-
 static int __init nohalt_setup(char * str)
 {
-        pal_halt = can_do_pal_halt = 0;
+        cpu_idle_poll_ctrl(true);
         return 1;
 }
 __setup("nohalt", nohalt_setup);
 
-void
-update_pal_halt_status(int status)
-{
-        can_do_pal_halt = pal_halt && status;
-}
-
-/*
- * We use this if we don't have any better idle routine..
- */
-void
-default_idle (void)
-{
-        local_irq_enable();
-        while (!need_resched()) {
-                if (can_do_pal_halt) {
-                        local_irq_disable();
-                        if (!need_resched()) {
-                                safe_halt();
-                        }
-                        local_irq_enable();
-                } else
-                        cpu_relax();
-        }
-}
-
 #ifdef CONFIG_HOTPLUG_CPU
 /* We don't actually take CPU down, just spin without interrupts. */
 static inline void play_dead(void)
@@ -270,47 +242,29 @@ static inline void play_dead(void)
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
-void __attribute__((noreturn))
-cpu_idle (void)
+void arch_cpu_idle_dead(void)
+{
+        play_dead();
+}
+
+void arch_cpu_idle(void)
 {
         void (*mark_idle)(int) = ia64_mark_idle;
-        int cpu = smp_processor_id();
-
-        /* endless idle loop with no priority at all */
-        while (1) {
-                rcu_idle_enter();
-                if (can_do_pal_halt) {
-                        current_thread_info()->status &= ~TS_POLLING;
-                        /*
-                         * TS_POLLING-cleared state must be visible before we
-                         * test NEED_RESCHED:
-                         */
-                        smp_mb();
-                } else {
-                        current_thread_info()->status |= TS_POLLING;
-                }
 
-                if (!need_resched()) {
 #ifdef CONFIG_SMP
-                        min_xtp();
+        min_xtp();
 #endif
-                        rmb();
-                        if (mark_idle)
-                                (*mark_idle)(1);
+        rmb();
+        if (mark_idle)
+                (*mark_idle)(1);
+
+        safe_halt();
 
-                        default_idle();
-                        if (mark_idle)
-                                (*mark_idle)(0);
+        if (mark_idle)
+                (*mark_idle)(0);
 #ifdef CONFIG_SMP
-                        normal_xtp();
+        normal_xtp();
 #endif
-                }
-                rcu_idle_exit();
-                schedule_preempt_disabled();
-                check_pgt_cache();
-                if (cpu_is_offline(cpu))
-                        play_dead();
-        }
 }
 
 void
diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index 500f1e4d9f9d..8d87168d218d 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -455,7 +455,7 @@ start_secondary (void *unused)
         preempt_disable();
         smp_callin();
 
-        cpu_idle();
+        cpu_startup_entry(CPUHP_ONLINE);
         return 0;
 }