552 lines
14 KiB
C
552 lines
14 KiB
C
/*
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* arch/s390/kernel/vtime.c
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* Virtual cpu timer based timer functions.
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*
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* S390 version
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* Copyright (C) 2004 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Jan Glauber <jan.glauber@de.ibm.com>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/time.h>
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/smp.h>
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#include <linux/types.h>
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#include <linux/timex.h>
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#include <linux/notifier.h>
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#include <linux/kernel_stat.h>
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#include <linux/rcupdate.h>
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#include <linux/posix-timers.h>
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#include <asm/s390_ext.h>
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#include <asm/timer.h>
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#include <asm/irq_regs.h>
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#include <asm/cpu.h>
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static ext_int_info_t ext_int_info_timer;
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static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);
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DEFINE_PER_CPU(struct s390_idle_data, s390_idle) = {
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.lock = __SPIN_LOCK_UNLOCKED(s390_idle.lock)
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};
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static inline __u64 get_vtimer(void)
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{
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__u64 timer;
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asm volatile("STPT %0" : "=m" (timer));
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return timer;
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}
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static inline void set_vtimer(__u64 expires)
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{
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__u64 timer;
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asm volatile (" STPT %0\n" /* Store current cpu timer value */
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" SPT %1" /* Set new value immediatly afterwards */
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: "=m" (timer) : "m" (expires) );
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S390_lowcore.system_timer += S390_lowcore.last_update_timer - timer;
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S390_lowcore.last_update_timer = expires;
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}
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/*
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* Update process times based on virtual cpu times stored by entry.S
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* to the lowcore fields user_timer, system_timer & steal_clock.
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*/
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static void do_account_vtime(struct task_struct *tsk, int hardirq_offset)
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{
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struct thread_info *ti = task_thread_info(tsk);
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__u64 timer, clock, user, system, steal;
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timer = S390_lowcore.last_update_timer;
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clock = S390_lowcore.last_update_clock;
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asm volatile (" STPT %0\n" /* Store current cpu timer value */
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" STCK %1" /* Store current tod clock value */
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: "=m" (S390_lowcore.last_update_timer),
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"=m" (S390_lowcore.last_update_clock) );
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S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
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S390_lowcore.steal_timer += S390_lowcore.last_update_clock - clock;
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user = S390_lowcore.user_timer - ti->user_timer;
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S390_lowcore.steal_timer -= user;
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ti->user_timer = S390_lowcore.user_timer;
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account_user_time(tsk, user, user);
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system = S390_lowcore.system_timer - ti->system_timer;
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S390_lowcore.steal_timer -= system;
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ti->system_timer = S390_lowcore.system_timer;
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account_system_time(tsk, hardirq_offset, system, system);
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steal = S390_lowcore.steal_timer;
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if ((s64) steal > 0) {
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S390_lowcore.steal_timer = 0;
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account_steal_time(steal);
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}
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}
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void account_vtime(struct task_struct *prev, struct task_struct *next)
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{
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struct thread_info *ti;
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do_account_vtime(prev, 0);
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ti = task_thread_info(prev);
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ti->user_timer = S390_lowcore.user_timer;
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ti->system_timer = S390_lowcore.system_timer;
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ti = task_thread_info(next);
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S390_lowcore.user_timer = ti->user_timer;
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S390_lowcore.system_timer = ti->system_timer;
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}
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void account_process_tick(struct task_struct *tsk, int user_tick)
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{
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do_account_vtime(tsk, HARDIRQ_OFFSET);
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}
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/*
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* Update process times based on virtual cpu times stored by entry.S
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* to the lowcore fields user_timer, system_timer & steal_clock.
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*/
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void account_system_vtime(struct task_struct *tsk)
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{
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struct thread_info *ti = task_thread_info(tsk);
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__u64 timer, system;
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timer = S390_lowcore.last_update_timer;
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S390_lowcore.last_update_timer = get_vtimer();
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S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
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system = S390_lowcore.system_timer - ti->system_timer;
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S390_lowcore.steal_timer -= system;
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ti->system_timer = S390_lowcore.system_timer;
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account_system_time(tsk, 0, system, system);
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}
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EXPORT_SYMBOL_GPL(account_system_vtime);
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void vtime_start_cpu(void)
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{
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struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
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struct vtimer_queue *vq = &__get_cpu_var(virt_cpu_timer);
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__u64 idle_time, expires;
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/* Account time spent with enabled wait psw loaded as idle time. */
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idle_time = S390_lowcore.int_clock - idle->idle_enter;
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account_idle_time(idle_time);
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S390_lowcore.steal_timer +=
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idle->idle_enter - S390_lowcore.last_update_clock;
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S390_lowcore.last_update_clock = S390_lowcore.int_clock;
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/* Account system time spent going idle. */
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S390_lowcore.system_timer += S390_lowcore.last_update_timer - vq->idle;
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S390_lowcore.last_update_timer = S390_lowcore.async_enter_timer;
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/* Restart vtime CPU timer */
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if (vq->do_spt) {
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/* Program old expire value but first save progress. */
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expires = vq->idle - S390_lowcore.async_enter_timer;
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expires += get_vtimer();
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set_vtimer(expires);
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} else {
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/* Don't account the CPU timer delta while the cpu was idle. */
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vq->elapsed -= vq->idle - S390_lowcore.async_enter_timer;
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}
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spin_lock(&idle->lock);
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idle->idle_time += idle_time;
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idle->idle_enter = 0ULL;
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idle->idle_count++;
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spin_unlock(&idle->lock);
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}
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void vtime_stop_cpu(void)
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{
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struct s390_idle_data *idle = &__get_cpu_var(s390_idle);
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struct vtimer_queue *vq = &__get_cpu_var(virt_cpu_timer);
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psw_t psw;
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/* Wait for external, I/O or machine check interrupt. */
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psw.mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_IO | PSW_MASK_EXT;
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/* Check if the CPU timer needs to be reprogrammed. */
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if (vq->do_spt) {
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__u64 vmax = VTIMER_MAX_SLICE;
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/*
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* The inline assembly is equivalent to
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* vq->idle = get_cpu_timer();
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* set_cpu_timer(VTIMER_MAX_SLICE);
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* idle->idle_enter = get_clock();
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* __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
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* PSW_MASK_IO | PSW_MASK_EXT);
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* The difference is that the inline assembly makes sure that
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* the last three instruction are stpt, stck and lpsw in that
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* order. This is done to increase the precision.
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*/
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asm volatile(
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#ifndef CONFIG_64BIT
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" basr 1,0\n"
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"0: ahi 1,1f-0b\n"
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" st 1,4(%2)\n"
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#else /* CONFIG_64BIT */
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" larl 1,1f\n"
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" stg 1,8(%2)\n"
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#endif /* CONFIG_64BIT */
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" stpt 0(%4)\n"
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" spt 0(%5)\n"
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" stck 0(%3)\n"
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#ifndef CONFIG_64BIT
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" lpsw 0(%2)\n"
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#else /* CONFIG_64BIT */
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" lpswe 0(%2)\n"
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#endif /* CONFIG_64BIT */
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"1:"
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: "=m" (idle->idle_enter), "=m" (vq->idle)
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: "a" (&psw), "a" (&idle->idle_enter),
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"a" (&vq->idle), "a" (&vmax), "m" (vmax), "m" (psw)
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: "memory", "cc", "1");
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} else {
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/*
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* The inline assembly is equivalent to
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* vq->idle = get_cpu_timer();
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* idle->idle_enter = get_clock();
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* __load_psw_mask(psw_kernel_bits | PSW_MASK_WAIT |
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* PSW_MASK_IO | PSW_MASK_EXT);
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* The difference is that the inline assembly makes sure that
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* the last three instruction are stpt, stck and lpsw in that
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* order. This is done to increase the precision.
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*/
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asm volatile(
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#ifndef CONFIG_64BIT
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" basr 1,0\n"
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"0: ahi 1,1f-0b\n"
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" st 1,4(%2)\n"
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#else /* CONFIG_64BIT */
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" larl 1,1f\n"
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" stg 1,8(%2)\n"
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#endif /* CONFIG_64BIT */
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" stpt 0(%4)\n"
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" stck 0(%3)\n"
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#ifndef CONFIG_64BIT
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" lpsw 0(%2)\n"
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#else /* CONFIG_64BIT */
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" lpswe 0(%2)\n"
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#endif /* CONFIG_64BIT */
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"1:"
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: "=m" (idle->idle_enter), "=m" (vq->idle)
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: "a" (&psw), "a" (&idle->idle_enter),
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"a" (&vq->idle), "m" (psw)
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: "memory", "cc", "1");
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}
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}
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/*
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* Sorted add to a list. List is linear searched until first bigger
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* element is found.
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*/
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static void list_add_sorted(struct vtimer_list *timer, struct list_head *head)
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{
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struct vtimer_list *event;
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list_for_each_entry(event, head, entry) {
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if (event->expires > timer->expires) {
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list_add_tail(&timer->entry, &event->entry);
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return;
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}
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}
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list_add_tail(&timer->entry, head);
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}
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/*
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* Do the callback functions of expired vtimer events.
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* Called from within the interrupt handler.
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*/
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static void do_callbacks(struct list_head *cb_list)
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{
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struct vtimer_queue *vq;
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struct vtimer_list *event, *tmp;
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if (list_empty(cb_list))
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return;
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vq = &__get_cpu_var(virt_cpu_timer);
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list_for_each_entry_safe(event, tmp, cb_list, entry) {
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list_del_init(&event->entry);
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(event->function)(event->data);
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if (event->interval) {
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/* Recharge interval timer */
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event->expires = event->interval + vq->elapsed;
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spin_lock(&vq->lock);
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list_add_sorted(event, &vq->list);
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spin_unlock(&vq->lock);
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}
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}
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}
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/*
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* Handler for the virtual CPU timer.
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*/
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static void do_cpu_timer_interrupt(__u16 error_code)
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{
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struct vtimer_queue *vq;
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struct vtimer_list *event, *tmp;
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struct list_head cb_list; /* the callback queue */
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__u64 elapsed, next;
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INIT_LIST_HEAD(&cb_list);
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vq = &__get_cpu_var(virt_cpu_timer);
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/* walk timer list, fire all expired events */
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spin_lock(&vq->lock);
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elapsed = vq->elapsed + (vq->timer - S390_lowcore.async_enter_timer);
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BUG_ON((s64) elapsed < 0);
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vq->elapsed = 0;
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list_for_each_entry_safe(event, tmp, &vq->list, entry) {
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if (event->expires < elapsed)
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/* move expired timer to the callback queue */
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list_move_tail(&event->entry, &cb_list);
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else
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event->expires -= elapsed;
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}
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spin_unlock(&vq->lock);
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vq->do_spt = list_empty(&cb_list);
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do_callbacks(&cb_list);
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/* next event is first in list */
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next = VTIMER_MAX_SLICE;
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spin_lock(&vq->lock);
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if (!list_empty(&vq->list)) {
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event = list_first_entry(&vq->list, struct vtimer_list, entry);
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next = event->expires;
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} else
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vq->do_spt = 0;
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spin_unlock(&vq->lock);
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/*
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* To improve precision add the time spent by the
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* interrupt handler to the elapsed time.
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* Note: CPU timer counts down and we got an interrupt,
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* the current content is negative
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*/
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elapsed = S390_lowcore.async_enter_timer - get_vtimer();
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set_vtimer(next - elapsed);
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vq->timer = next - elapsed;
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vq->elapsed = elapsed;
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}
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void init_virt_timer(struct vtimer_list *timer)
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{
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timer->function = NULL;
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INIT_LIST_HEAD(&timer->entry);
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}
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EXPORT_SYMBOL(init_virt_timer);
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static inline int vtimer_pending(struct vtimer_list *timer)
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{
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return (!list_empty(&timer->entry));
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}
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/*
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* this function should only run on the specified CPU
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*/
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static void internal_add_vtimer(struct vtimer_list *timer)
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{
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struct vtimer_queue *vq;
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unsigned long flags;
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__u64 left, expires;
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vq = &per_cpu(virt_cpu_timer, timer->cpu);
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spin_lock_irqsave(&vq->lock, flags);
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BUG_ON(timer->cpu != smp_processor_id());
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if (list_empty(&vq->list)) {
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/* First timer on this cpu, just program it. */
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list_add(&timer->entry, &vq->list);
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set_vtimer(timer->expires);
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vq->timer = timer->expires;
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vq->elapsed = 0;
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} else {
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/* Check progress of old timers. */
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expires = timer->expires;
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left = get_vtimer();
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if (likely((s64) expires < (s64) left)) {
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/* The new timer expires before the current timer. */
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set_vtimer(expires);
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vq->elapsed += vq->timer - left;
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vq->timer = expires;
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} else {
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vq->elapsed += vq->timer - left;
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vq->timer = left;
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}
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/* Insert new timer into per cpu list. */
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timer->expires += vq->elapsed;
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list_add_sorted(timer, &vq->list);
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}
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spin_unlock_irqrestore(&vq->lock, flags);
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/* release CPU acquired in prepare_vtimer or mod_virt_timer() */
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put_cpu();
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}
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static inline void prepare_vtimer(struct vtimer_list *timer)
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{
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BUG_ON(!timer->function);
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BUG_ON(!timer->expires || timer->expires > VTIMER_MAX_SLICE);
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BUG_ON(vtimer_pending(timer));
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timer->cpu = get_cpu();
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}
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/*
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* add_virt_timer - add an oneshot virtual CPU timer
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*/
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void add_virt_timer(void *new)
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{
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struct vtimer_list *timer;
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timer = (struct vtimer_list *)new;
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prepare_vtimer(timer);
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timer->interval = 0;
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internal_add_vtimer(timer);
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}
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EXPORT_SYMBOL(add_virt_timer);
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/*
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* add_virt_timer_int - add an interval virtual CPU timer
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*/
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void add_virt_timer_periodic(void *new)
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{
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struct vtimer_list *timer;
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timer = (struct vtimer_list *)new;
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prepare_vtimer(timer);
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timer->interval = timer->expires;
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internal_add_vtimer(timer);
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}
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EXPORT_SYMBOL(add_virt_timer_periodic);
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int __mod_vtimer(struct vtimer_list *timer, __u64 expires, int periodic)
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{
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struct vtimer_queue *vq;
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unsigned long flags;
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int cpu;
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BUG_ON(!timer->function);
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BUG_ON(!expires || expires > VTIMER_MAX_SLICE);
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if (timer->expires == expires && vtimer_pending(timer))
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return 1;
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cpu = get_cpu();
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vq = &per_cpu(virt_cpu_timer, cpu);
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/* disable interrupts before test if timer is pending */
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spin_lock_irqsave(&vq->lock, flags);
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/* if timer isn't pending add it on the current CPU */
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if (!vtimer_pending(timer)) {
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spin_unlock_irqrestore(&vq->lock, flags);
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if (periodic)
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timer->interval = expires;
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else
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timer->interval = 0;
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timer->expires = expires;
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timer->cpu = cpu;
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internal_add_vtimer(timer);
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return 0;
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}
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/* check if we run on the right CPU */
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BUG_ON(timer->cpu != cpu);
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list_del_init(&timer->entry);
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timer->expires = expires;
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if (periodic)
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timer->interval = expires;
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/* the timer can't expire anymore so we can release the lock */
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spin_unlock_irqrestore(&vq->lock, flags);
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internal_add_vtimer(timer);
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return 1;
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}
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/*
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* If we change a pending timer the function must be called on the CPU
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* where the timer is running on.
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*
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* returns whether it has modified a pending timer (1) or not (0)
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*/
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int mod_virt_timer(struct vtimer_list *timer, __u64 expires)
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{
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return __mod_vtimer(timer, expires, 0);
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}
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EXPORT_SYMBOL(mod_virt_timer);
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/*
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* If we change a pending timer the function must be called on the CPU
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* where the timer is running on.
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*
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* returns whether it has modified a pending timer (1) or not (0)
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*/
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int mod_virt_timer_periodic(struct vtimer_list *timer, __u64 expires)
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{
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return __mod_vtimer(timer, expires, 1);
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}
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|
EXPORT_SYMBOL(mod_virt_timer_periodic);
|
|
|
|
/*
|
|
* delete a virtual timer
|
|
*
|
|
* returns whether the deleted timer was pending (1) or not (0)
|
|
*/
|
|
int del_virt_timer(struct vtimer_list *timer)
|
|
{
|
|
unsigned long flags;
|
|
struct vtimer_queue *vq;
|
|
|
|
/* check if timer is pending */
|
|
if (!vtimer_pending(timer))
|
|
return 0;
|
|
|
|
vq = &per_cpu(virt_cpu_timer, timer->cpu);
|
|
spin_lock_irqsave(&vq->lock, flags);
|
|
|
|
/* we don't interrupt a running timer, just let it expire! */
|
|
list_del_init(&timer->entry);
|
|
|
|
spin_unlock_irqrestore(&vq->lock, flags);
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(del_virt_timer);
|
|
|
|
/*
|
|
* Start the virtual CPU timer on the current CPU.
|
|
*/
|
|
void init_cpu_vtimer(void)
|
|
{
|
|
struct vtimer_queue *vq;
|
|
|
|
/* initialize per cpu vtimer structure */
|
|
vq = &__get_cpu_var(virt_cpu_timer);
|
|
INIT_LIST_HEAD(&vq->list);
|
|
spin_lock_init(&vq->lock);
|
|
|
|
/* enable cpu timer interrupts */
|
|
__ctl_set_bit(0,10);
|
|
}
|
|
|
|
void __init vtime_init(void)
|
|
{
|
|
/* request the cpu timer external interrupt */
|
|
if (register_early_external_interrupt(0x1005, do_cpu_timer_interrupt,
|
|
&ext_int_info_timer) != 0)
|
|
panic("Couldn't request external interrupt 0x1005");
|
|
|
|
/* Enable cpu timer interrupts on the boot cpu. */
|
|
init_cpu_vtimer();
|
|
}
|
|
|