1 files changed, 187 insertions, 136 deletions

diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 3fb09359eda6..234a0ba30510 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  *    Virtual cpu timer based timer functions.
  *
@@ -6,49 +7,43 @@
  */
 
 #include <linux/kernel_stat.h>
-#include <linux/notifier.h>
-#include <linux/kprobes.h>
 #include <linux/export.h>
 #include <linux/kernel.h>
 #include <linux/timex.h>
 #include <linux/types.h>
 #include <linux/time.h>
-#include <linux/cpu.h>
-#include <linux/smp.h>
-
-#include <asm/irq_regs.h>
+#include <asm/alternative.h>
 #include <asm/cputime.h>
 #include <asm/vtimer.h>
-#include <asm/irq.h>
+#include <asm/vtime.h>
+#include <asm/cpu_mf.h>
+#include <asm/smp.h>
+
 #include "entry.h"
 
 static void virt_timer_expire(void);
 
-DEFINE_PER_CPU(struct s390_idle_data, s390_idle);
-
 static LIST_HEAD(virt_timer_list);
 static DEFINE_SPINLOCK(virt_timer_lock);
 static atomic64_t virt_timer_current;
 static atomic64_t virt_timer_elapsed;
 
-static inline u64 get_vtimer(void)
-{
-	u64 timer;
-
-	asm volatile("stpt %0" : "=m" (timer));
-	return timer;
-}
+DEFINE_PER_CPU(u64, mt_cycles[8]);
+static DEFINE_PER_CPU(u64, mt_scaling_mult) = { 1 };
+static DEFINE_PER_CPU(u64, mt_scaling_div) = { 1 };
+static DEFINE_PER_CPU(u64, mt_scaling_jiffies);
 
 static inline void set_vtimer(u64 expires)
 {
+	struct lowcore *lc = get_lowcore();
 	u64 timer;
 
 	asm volatile(
 		"	stpt	%0\n"	/* Store current cpu timer value */
 		"	spt	%1"	/* Set new value imm. afterwards */
-		: "=m" (timer) : "m" (expires));
-	S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
-	S390_lowcore.last_update_timer = expires;
+		: "=Q" (timer) : "Q" (expires));
+	lc->system_timer += lc->last_update_timer - timer;
+	lc->last_update_timer = expires;
 }
 
 static inline int virt_timer_forward(u64 elapsed)
@@ -61,55 +56,141 @@ static inline int virt_timer_forward(u64 elapsed)
 	return elapsed >= atomic64_read(&virt_timer_current);
 }
 
+static void update_mt_scaling(void)
+{
+	u64 cycles_new[8], *cycles_old;
+	u64 delta, fac, mult, div;
+	int i;
+
+	stcctm(MT_DIAG, smp_cpu_mtid + 1, cycles_new);
+	cycles_old = this_cpu_ptr(mt_cycles);
+	fac = 1;
+	mult = div = 0;
+	for (i = 0; i <= smp_cpu_mtid; i++) {
+		delta = cycles_new[i] - cycles_old[i];
+		div += delta;
+		mult *= i + 1;
+		mult += delta * fac;
+		fac *= i + 1;
+	}
+	div *= fac;
+	if (div > 0) {
+		/* Update scaling factor */
+		__this_cpu_write(mt_scaling_mult, mult);
+		__this_cpu_write(mt_scaling_div, div);
+		memcpy(cycles_old, cycles_new,
+		       sizeof(u64) * (smp_cpu_mtid + 1));
+	}
+	__this_cpu_write(mt_scaling_jiffies, jiffies_64);
+}
+
+static inline u64 update_tsk_timer(unsigned long *tsk_vtime, u64 new)
+{
+	u64 delta;
+
+	delta = new - *tsk_vtime;
+	*tsk_vtime = new;
+	return delta;
+}
+
+
+static inline u64 scale_vtime(u64 vtime)
+{
+	u64 mult = __this_cpu_read(mt_scaling_mult);
+	u64 div = __this_cpu_read(mt_scaling_div);
+
+	if (smp_cpu_mtid)
+		return vtime * mult / div;
+	return vtime;
+}
+
+static void account_system_index_scaled(struct task_struct *p, u64 cputime,
+					enum cpu_usage_stat index)
+{
+	p->stimescaled += cputime_to_nsecs(scale_vtime(cputime));
+	account_system_index_time(p, cputime_to_nsecs(cputime), index);
+}
+
 /*
  * Update process times based on virtual cpu times stored by entry.S
  * to the lowcore fields user_timer, system_timer & steal_clock.
  */
-static int do_account_vtime(struct task_struct *tsk, int hardirq_offset)
+static int do_account_vtime(struct task_struct *tsk)
 {
-	struct thread_info *ti = task_thread_info(tsk);
-	u64 timer, clock, user, system, steal;
+	u64 timer, clock, user, guest, system, hardirq, softirq;
+	struct lowcore *lc = get_lowcore();
 
-	timer = S390_lowcore.last_update_timer;
-	clock = S390_lowcore.last_update_clock;
+	timer = lc->last_update_timer;
+	clock = lc->last_update_clock;
 	asm volatile(
 		"	stpt	%0\n"	/* Store current cpu timer value */
-		"	stck	%1"	/* Store current tod clock value */
-		: "=m" (S390_lowcore.last_update_timer),
-		  "=m" (S390_lowcore.last_update_clock));
-	S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
-	S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock;
-
-	user = S390_lowcore.user_timer - ti->user_timer;
-	S390_lowcore.steal_timer -= user;
-	ti->user_timer = S390_lowcore.user_timer;
-	account_user_time(tsk, user, user);
-
-	system = S390_lowcore.system_timer - ti->system_timer;
-	S390_lowcore.steal_timer -= system;
-	ti->system_timer = S390_lowcore.system_timer;
-	account_system_time(tsk, hardirq_offset, system, system);
-
-	steal = S390_lowcore.steal_timer;
-	if ((s64) steal > 0) {
-		S390_lowcore.steal_timer = 0;
-		account_steal_time(steal);
+		"	stckf	%1"	/* Store current tod clock value */
+		: "=Q" (lc->last_update_timer),
+		  "=Q" (lc->last_update_clock)
+		: : "cc");
+	clock = lc->last_update_clock - clock;
+	timer -= lc->last_update_timer;
+
+	if (hardirq_count())
+		lc->hardirq_timer += timer;
+	else
+		lc->system_timer += timer;
+
+	/* Update MT utilization calculation */
+	if (smp_cpu_mtid &&
+	    time_after64(jiffies_64, this_cpu_read(mt_scaling_jiffies)))
+		update_mt_scaling();
+
+	/* Calculate cputime delta */
+	user = update_tsk_timer(&tsk->thread.user_timer,
+				READ_ONCE(lc->user_timer));
+	guest = update_tsk_timer(&tsk->thread.guest_timer,
+				 READ_ONCE(lc->guest_timer));
+	system = update_tsk_timer(&tsk->thread.system_timer,
+				  READ_ONCE(lc->system_timer));
+	hardirq = update_tsk_timer(&tsk->thread.hardirq_timer,
+				   READ_ONCE(lc->hardirq_timer));
+	softirq = update_tsk_timer(&tsk->thread.softirq_timer,
+				   READ_ONCE(lc->softirq_timer));
+	lc->steal_timer +=
+		clock - user - guest - system - hardirq - softirq;
+
+	/* Push account value */
+	if (user) {
+		account_user_time(tsk, cputime_to_nsecs(user));
+		tsk->utimescaled += cputime_to_nsecs(scale_vtime(user));
 	}
 
-	return virt_timer_forward(user + system);
+	if (guest) {
+		account_guest_time(tsk, cputime_to_nsecs(guest));
+		tsk->utimescaled += cputime_to_nsecs(scale_vtime(guest));
+	}
+
+	if (system)
+		account_system_index_scaled(tsk, system, CPUTIME_SYSTEM);
+	if (hardirq)
+		account_system_index_scaled(tsk, hardirq, CPUTIME_IRQ);
+	if (softirq)
+		account_system_index_scaled(tsk, softirq, CPUTIME_SOFTIRQ);
+
+	return virt_timer_forward(user + guest + system + hardirq + softirq);
 }
 
 void vtime_task_switch(struct task_struct *prev)
 {
-	struct thread_info *ti;
-
-	do_account_vtime(prev, 0);
-	ti = task_thread_info(prev);
-	ti->user_timer = S390_lowcore.user_timer;
-	ti->system_timer = S390_lowcore.system_timer;
-	ti = task_thread_info(current);
-	S390_lowcore.user_timer = ti->user_timer;
-	S390_lowcore.system_timer = ti->system_timer;
+	struct lowcore *lc = get_lowcore();
+
+	do_account_vtime(prev);
+	prev->thread.user_timer = lc->user_timer;
+	prev->thread.guest_timer = lc->guest_timer;
+	prev->thread.system_timer = lc->system_timer;
+	prev->thread.hardirq_timer = lc->hardirq_timer;
+	prev->thread.softirq_timer = lc->softirq_timer;
+	lc->user_timer = current->thread.user_timer;
+	lc->guest_timer = current->thread.guest_timer;
+	lc->system_timer = current->thread.system_timer;
+	lc->hardirq_timer = current->thread.hardirq_timer;
+	lc->softirq_timer = current->thread.softirq_timer;
 }
 
 /*
@@ -117,81 +198,67 @@ void vtime_task_switch(struct task_struct *prev)
  * accounting system time in order to correctly compute
  * the stolen time accounting.
  */
-void vtime_account_user(struct task_struct *tsk)
+void vtime_flush(struct task_struct *tsk)
 {
-	if (do_account_vtime(tsk, HARDIRQ_OFFSET))
+	struct lowcore *lc = get_lowcore();
+	u64 steal, avg_steal;
+
+	if (do_account_vtime(tsk))
 		virt_timer_expire();
+
+	steal = lc->steal_timer;
+	avg_steal = lc->avg_steal_timer;
+	if ((s64) steal > 0) {
+		lc->steal_timer = 0;
+		account_steal_time(cputime_to_nsecs(steal));
+		avg_steal += steal;
+	}
+	lc->avg_steal_timer = avg_steal / 2;
+}
+
+static u64 vtime_delta(void)
+{
+	struct lowcore *lc = get_lowcore();
+	u64 timer = lc->last_update_timer;
+
+	lc->last_update_timer = get_cpu_timer();
+	return timer - lc->last_update_timer;
 }
 
 /*
  * Update process times based on virtual cpu times stored by entry.S
  * to the lowcore fields user_timer, system_timer & steal_clock.
  */
-void vtime_account_irq_enter(struct task_struct *tsk)
+void vtime_account_kernel(struct task_struct *tsk)
 {
-	struct thread_info *ti = task_thread_info(tsk);
-	u64 timer, system;
-
-	WARN_ON_ONCE(!irqs_disabled());
+	struct lowcore *lc = get_lowcore();
+	u64 delta = vtime_delta();
 
-	timer = S390_lowcore.last_update_timer;
-	S390_lowcore.last_update_timer = get_vtimer();
-	S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
+	if (tsk->flags & PF_VCPU)
+		lc->guest_timer += delta;
+	else
+		lc->system_timer += delta;
 
-	system = S390_lowcore.system_timer - ti->system_timer;
-	S390_lowcore.steal_timer -= system;
-	ti->system_timer = S390_lowcore.system_timer;
-	account_system_time(tsk, 0, system, system);
-
-	virt_timer_forward(system);
+	virt_timer_forward(delta);
 }
-EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
-
-void vtime_account_system(struct task_struct *tsk)
-__attribute__((alias("vtime_account_irq_enter")));
-EXPORT_SYMBOL_GPL(vtime_account_system);
+EXPORT_SYMBOL_GPL(vtime_account_kernel);
 
-void __kprobes vtime_stop_cpu(void)
+void vtime_account_softirq(struct task_struct *tsk)
 {
-	struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
-	unsigned long long idle_time;
-	unsigned long psw_mask;
-
-	trace_hardirqs_on();
-
-	/* Wait for external, I/O or machine check interrupt. */
-	psw_mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_DAT |
-		PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
-	idle->nohz_delay = 0;
-
-	/* Call the assembler magic in entry.S */
-	psw_idle(idle, psw_mask);
-
-	/* Account time spent with enabled wait psw loaded as idle time. */
-	idle->sequence++;
-	smp_wmb();
-	idle_time = idle->clock_idle_exit - idle->clock_idle_enter;
-	idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
-	idle->idle_time += idle_time;
-	idle->idle_count++;
-	account_idle_time(idle_time);
-	smp_wmb();
-	idle->sequence++;
+	u64 delta = vtime_delta();
+
+	get_lowcore()->softirq_timer += delta;
+
+	virt_timer_forward(delta);
 }
 
-cputime64_t s390_get_idle_time(int cpu)
+void vtime_account_hardirq(struct task_struct *tsk)
 {
-	struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
-	unsigned long long now, idle_enter, idle_exit;
-	unsigned int sequence;
-
-	do {
-		now = get_tod_clock();
-		sequence = ACCESS_ONCE(idle->sequence);
-		idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
-		idle_exit = ACCESS_ONCE(idle->clock_idle_exit);
-	} while ((sequence & 1) || (idle->sequence != sequence));
-	return idle_enter ? ((idle_exit ?: now) - idle_enter) : 0;
+	u64 delta = vtime_delta();
+
+	get_lowcore()->hardirq_timer += delta;
+
+	virt_timer_forward(delta);
 }
 
 /*
@@ -295,7 +362,7 @@ static void __add_vtimer(struct vtimer_list *timer, int periodic)
 }
 
 /*
- * add_virt_timer - add an oneshot virtual CPU timer
+ * add_virt_timer - add a oneshot virtual CPU timer
  */
 void add_virt_timer(struct vtimer_list *timer)
 {
@@ -371,31 +438,15 @@ EXPORT_SYMBOL(del_virt_timer);
 /*
  * Start the virtual CPU timer on the current CPU.
  */
-void __cpuinit init_cpu_vtimer(void)
+void vtime_init(void)
 {
 	/* set initial cpu timer */
 	set_vtimer(VTIMER_MAX_SLICE);
-}
-
-static int __cpuinit s390_nohz_notify(struct notifier_block *self,
-				      unsigned long action, void *hcpu)
-{
-	struct s390_idle_data *idle;
-	long cpu = (long) hcpu;
-
-	idle = &per_cpu(s390_idle, cpu);
-	switch (action & ~CPU_TASKS_FROZEN) {
-	case CPU_DYING:
-		idle->nohz_delay = 0;
-	default:
-		break;
+	/* Setup initial MT scaling values */
+	if (smp_cpu_mtid) {
+		__this_cpu_write(mt_scaling_jiffies, jiffies);
+		__this_cpu_write(mt_scaling_mult, 1);
+		__this_cpu_write(mt_scaling_div, 1);
+		stcctm(MT_DIAG, smp_cpu_mtid + 1, this_cpu_ptr(mt_cycles));
 	}
-	return NOTIFY_OK;
-}
-
-void __init vtime_init(void)
-{
-	/* Enable cpu timer interrupts on the boot cpu. */
-	init_cpu_vtimer();
-	cpu_notifier(s390_nohz_notify, 0);
 }