timekeeping: add CONFIG_LEGACY_TIMER_TICK

All platforms that currently do not use generic clockevents roughly call
the same set of functions in their timer interrupts: xtime_update(),
update_process_times() and profile_tick(), sometimes in a different
sequence.

Add a helper function that performs all three of them, to make the
callers more uniform and simplify the interface.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 19 insertions, 0 deletions

diff --git a/kernel/time/tick-legacy.c b/kernel/time/tick-legacy.c
new file mode 100644
index 00000000000000..73c5a0af474337
--- /dev/null
+++ b/kernel/time/tick-legacy.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Timer tick function for architectures that lack generic clockevents,
+ * consolidated here from m68k/ia64/parisc/arm.
+ */
+
+#include <linux/irq.h>
+#include <linux/profile.h>
+#include <linux/timekeeper_internal.h>
+
+#include "tick-internal.h"
+
+void legacy_timer_tick(unsigned long ticks)
+{
+	if (ticks)
+		xtime_update(ticks);
+	update_process_times(user_mode(get_irq_regs()));
+	profile_tick(CPU_PROFILING);
+}