[S390] Convert monitor calls to function calls.

Remove the program check generating monitor calls and use function
calls instead. Theres is no real advantage in using monitor calls,
but they do make debugging harder, because of all the program checks
it generates.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

arch/s390/kernel/process.c

@@ -76,6 +76,7 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
  * Need to know about CPUs going idle?
  */
 static ATOMIC_NOTIFIER_HEAD(idle_chain);
+DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
 
 int register_idle_notifier(struct notifier_block *nb)
 {
@@ -89,9 +90,33 @@ int unregister_idle_notifier(struct notifier_block *nb)
 }
 EXPORT_SYMBOL(unregister_idle_notifier);
 
-void do_monitor_call(struct pt_regs *regs, long interruption_code)
+static int s390_idle_enter(void)
+{
+	struct s390_idle_data *idle;
+	int nr_calls = 0;
+	void *hcpu;
+	int rc;
+
+	hcpu = (void *)(long)smp_processor_id();
+	rc = __atomic_notifier_call_chain(&idle_chain, S390_CPU_IDLE, hcpu, -1,
+					  &nr_calls);
+	if (rc == NOTIFY_BAD) {
+		nr_calls--;
+		__atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
+					     hcpu, nr_calls, NULL);
+		return rc;
+	}
+	idle = &__get_cpu_var(s390_idle);
+	spin_lock(&idle->lock);
+	idle->idle_count++;
+	idle->in_idle = 1;
+	idle->idle_enter = get_clock();
+	spin_unlock(&idle->lock);
+	return NOTIFY_OK;
+}
+
+void s390_idle_leave(void)
 {
-#ifdef CONFIG_SMP
 	struct s390_idle_data *idle;
 
 	idle = &__get_cpu_var(s390_idle);
@@ -99,10 +124,6 @@ void do_monitor_call(struct pt_regs *regs, long interruption_code)
 	idle->idle_time += get_clock() - idle->idle_enter;
 	idle->in_idle = 0;
 	spin_unlock(&idle->lock);
-#endif
-	/* disable monitor call class 0 */
-	__ctl_clear_bit(8, 15);
-
 	atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
 				   (void *)(long) smp_processor_id());
 }
@@ -113,61 +134,30 @@ extern void s390_handle_mcck(void);
  */
 static void default_idle(void)
 {
-	int cpu, rc;
-	int nr_calls = 0;
-	void *hcpu;
-#ifdef CONFIG_SMP
-	struct s390_idle_data *idle;
-#endif
-
 	/* CPU is going idle. */
-	cpu = smp_processor_id();
-	hcpu = (void *)(long)cpu;
 	local_irq_disable();
 	if (need_resched()) {
 		local_irq_enable();
 		return;
 	}
-
-	rc = __atomic_notifier_call_chain(&idle_chain, S390_CPU_IDLE, hcpu, -1,
-					  &nr_calls);
-	if (rc == NOTIFY_BAD) {
-		nr_calls--;
-		__atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
-					     hcpu, nr_calls, NULL);
+	if (s390_idle_enter() == NOTIFY_BAD) {
 		local_irq_enable();
 		return;
 	}
-
-	/* enable monitor call class 0 */
-	__ctl_set_bit(8, 15);
-
 #ifdef CONFIG_HOTPLUG_CPU
-	if (cpu_is_offline(cpu)) {
+	if (cpu_is_offline(smp_processor_id())) {
 		preempt_enable_no_resched();
 		cpu_die();
 	}
 #endif
-
 	local_mcck_disable();
 	if (test_thread_flag(TIF_MCCK_PENDING)) {
 		local_mcck_enable();
-		/* disable monitor call class 0 */
-		__ctl_clear_bit(8, 15);
-		atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
-					   hcpu);
+		s390_idle_leave();
 		local_irq_enable();
 		s390_handle_mcck();
 		return;
 	}
-#ifdef CONFIG_SMP
-	idle = &__get_cpu_var(s390_idle);
-	spin_lock(&idle->lock);
-	idle->idle_count++;
-	idle->in_idle = 1;
-	idle->idle_enter = get_clock();
-	spin_unlock(&idle->lock);
-#endif
 	trace_hardirqs_on();
 	/* Wait for external, I/O or machine check interrupt. */
 	__load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |

arch/s390/kernel/s390_ext.c

@@ -13,7 +13,7 @@
 #include <linux/errno.h>
 #include <linux/kernel_stat.h>
 #include <linux/interrupt.h>
-
+#include <asm/cpu.h>
 #include <asm/lowcore.h>
 #include <asm/s390_ext.h>
 #include <asm/irq_regs.h>
@@ -119,7 +119,7 @@ void do_extint(struct pt_regs *regs, unsigned short code)
 
 	old_regs = set_irq_regs(regs);
 	irq_enter();
-	asm volatile ("mc 0,0");
+	s390_idle_check();
 	if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 		/**
 		 * Make sure that the i/o interrupt did not "overtake"

arch/s390/kernel/smp.c

@@ -73,7 +73,6 @@ static int smp_cpu_state[NR_CPUS];
 static int cpu_management;
 
 static DEFINE_PER_CPU(struct cpu, cpu_devices);
-DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
 
 static void smp_ext_bitcall(int, ec_bit_sig);
 

arch/s390/kernel/traps.c

@@ -59,7 +59,6 @@ int sysctl_userprocess_debug = 0;
 
 extern pgm_check_handler_t do_protection_exception;
 extern pgm_check_handler_t do_dat_exception;
-extern pgm_check_handler_t do_monitor_call;
 extern pgm_check_handler_t do_asce_exception;
 
 #define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
@@ -739,6 +738,5 @@ void __init trap_init(void)
         pgm_check_table[0x15] = &operand_exception;
         pgm_check_table[0x1C] = &space_switch_exception;
         pgm_check_table[0x1D] = &hfp_sqrt_exception;
-	pgm_check_table[0x40] = &do_monitor_call;
 	pfault_irq_init();
 }

drivers/s390/cio/cio.c

@@ -24,6 +24,7 @@
 #include <asm/ipl.h>
 #include <asm/chpid.h>
 #include <asm/airq.h>
+#include <asm/cpu.h>
 #include "cio.h"
 #include "css.h"
 #include "chsc.h"
@@ -649,7 +650,7 @@ do_IRQ (struct pt_regs *regs)
 
 	old_regs = set_irq_regs(regs);
 	irq_enter();
-	asm volatile ("mc 0,0");
+	s390_idle_check();
 	if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 		/**
 		 * Make sure that the i/o interrupt did not "overtake"

include/asm-s390/cpu.h

@@ -22,4 +22,12 @@ struct s390_idle_data {
 
 DECLARE_PER_CPU(struct s390_idle_data, s390_idle);
 
+void s390_idle_leave(void);
+
+static inline void s390_idle_check(void)
+{
+	if ((&__get_cpu_var(s390_idle))->in_idle)
+		s390_idle_leave();
+}
+
 #endif /* _ASM_S390_CPU_H_ */