kernel/time/tick-legacy.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Timer tick function for architectures that lack generic clockevents,
   4  * consolidated here from m68k/ia64/parisc/arm.
   5  */
   6
   7 #include <linux/irq.h>
   8 #include <linux/profile.h>
   9 #include <linux/timekeeper_internal.h>
  10
  11 #include "tick-internal.h"
  12
  13 /**
  14  * legacy_timer_tick() - advances the timekeeping infrastructure
  15  * @ticks:      number of ticks, that have elapsed since the last call.
  16  *
  17  * This is used by platforms that have not been converted to
  18  * generic clockevents.
  19  *
  20  * If 'ticks' is zero, the CPU is not handling timekeeping, so
  21  * only perform process accounting and profiling.
  22  *
  23  * Must be called with interrupts disabled.
  24  */
  25 void legacy_timer_tick(unsigned long ticks)
  26 {
  27         if (ticks) {
  28                 raw_spin_lock(&jiffies_lock);
  29                 write_seqcount_begin(&jiffies_seq);
  30                 do_timer(ticks);
  31                 write_seqcount_end(&jiffies_seq);
  32                 raw_spin_unlock(&jiffies_lock);
  33                 update_wall_time();
  34         }
  35         update_process_times(user_mode(get_irq_regs()));
  36         profile_tick(CPU_PROFILING);
  37 }