[PATCH 01/13] timekeeping: add CONFIG_LEGACY_TIMER_TICK

From: Arnd Bergmann <arnd@arndb.de>
To: linux-kernel@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>,
	Russell King <linux@armlinux.org.uk>,
	Tony Luck <tony.luck@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Greg Ungerer <gerg@linux-m68k.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Finn Thain <fthain@telegraphics.com.au>,
	Philip Blundell <philb@gnu.org>,
	Joshua Thompson <funaho@jurai.org>, Sam Creasey <sammy@sammy.net>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Daniel Lezcano <daniel.lezcano@linaro.org>,
	John Stultz <john.stultz@linaro.org>,
	Stephen Boyd <sboyd@kernel.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org,
	linux-m68k@lists.linux-m68k.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH 01/13] timekeeping: add CONFIG_LEGACY_TIMER_TICK
Date: Thu,  8 Oct 2020 17:46:39 +0200	[thread overview]
Message-ID: <20201008154651.1901126-2-arnd@arndb.de> (raw)
In-Reply-To: <20201008154651.1901126-1-arnd@arndb.de>

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.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 include/linux/timekeeping.h |  1 +
 kernel/time/Kconfig         |  7 +++++++
 kernel/time/Makefile        |  1 +
 kernel/time/tick-legacy.c   | 19 +++++++++++++++++++
 4 files changed, 28 insertions(+)
 create mode 100644 kernel/time/tick-legacy.c

diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index 7f7e4a3f4394..3670cb1670ff 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -12,6 +12,7 @@ extern int timekeeping_suspended;
 /* Architecture timer tick functions: */
 extern void update_process_times(int user);
 extern void xtime_update(unsigned long ticks);
+extern void legacy_timer_tick(unsigned long ticks);
 
 /*
  * Get and set timeofday
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index a09b1d61df6a..f2b0cfeade47 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -61,6 +61,13 @@ config POSIX_CPU_TIMERS_TASK_WORK
 	bool
 	default y if POSIX_TIMERS && HAVE_POSIX_CPU_TIMERS_TASK_WORK
 
+config LEGACY_TIMER_TICK
+	bool
+	help
+	  The legacy timer tick helper is used by platforms that
+	  lack support for the generic clockevent framework.
+	  New platforms should use generic clockevents instead.
+
 if GENERIC_CLOCKEVENTS
 menu "Timers subsystem"
 
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index c8f00168afe8..1fb1c1ef6a19 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -16,6 +16,7 @@ ifeq ($(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST),y)
 endif
 obj-$(CONFIG_GENERIC_SCHED_CLOCK)		+= sched_clock.o
 obj-$(CONFIG_TICK_ONESHOT)			+= tick-oneshot.o tick-sched.o
+obj-$(CONFIG_LEGACY_TIMER_TICK)			+= tick-legacy.o
 obj-$(CONFIG_HAVE_GENERIC_VDSO)			+= vsyscall.o
 obj-$(CONFIG_DEBUG_FS)				+= timekeeping_debug.o
 obj-$(CONFIG_TEST_UDELAY)			+= test_udelay.o
diff --git a/kernel/time/tick-legacy.c b/kernel/time/tick-legacy.c
new file mode 100644
index 000000000000..73c5a0af4743
--- /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);
+}
-- 
2.27.0

