Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "Nothing exciting, just the usual pile of fixes, updates and cleanups:

   - A bunch of clocksource driver updates

   - Removal of CONFIG_TIMER_STATS and the related /proc file

   - More posix timer slim down work

   - A scalability enhancement in the tick broadcast code

   - Math cleanups"

* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  hrtimer: Catch invalid clockids again
  math64, tile: Fix build failure
  clocksource/drivers/arm_arch_timer:: Mark cyclecounter __ro_after_init
  timerfd: Protect the might cancel mechanism proper
  timer_list: Remove useless cast when printing
  time: Remove CONFIG_TIMER_STATS
  clocksource/drivers/arm_arch_timer: Work around Hisilicon erratum 161010101
  clocksource/drivers/arm_arch_timer: Introduce generic errata handling infrastructure
  clocksource/drivers/arm_arch_timer: Remove fsl-a008585 parameter
  clocksource/drivers/arm_arch_timer: Add dt binding for hisilicon-161010101 erratum
  clocksource/drivers/ostm: Add renesas-ostm timer driver
  clocksource/drivers/ostm: Document renesas-ostm timer DT bindings
  clocksource/drivers/tcb_clksrc: Use 32 bit tcb as sched_clock
  clocksource/drivers/gemini: Add driver for the Cortina Gemini
  clocksource: add DT bindings for Cortina Gemini
  clockevents: Add a clkevt-of mechanism like clksrc-of
  tick/broadcast: Reduce lock cacheline contention
  timers: Omit POSIX timer stuff from task_struct when disabled
  x86/timer: Make delay() work during early bootup
  delay: Add explanation of udelay() inaccuracy
  ...

8 files changed, 79 insertions, 83 deletions

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index 0d442e34c349..5d3053c34fb3 100644
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -224,4 +224,13 @@ static inline void tick_setup_hrtimer_broadcast(void) { }
 
 #endif /* !CONFIG_GENERIC_CLOCKEVENTS */
 
+#define CLOCKEVENT_OF_DECLARE(name, compat, fn) \
+	OF_DECLARE_1_RET(clkevt, name, compat, fn)
+
+#ifdef CONFIG_CLKEVT_PROBE
+extern int clockevent_probe(void);
+#els
+static inline int clockevent_probe(void) { return 0; }
+#endif
+
 #endif /* _LINUX_CLOCKCHIPS_H */
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index b3d2c1a89ac4..96f1e88b767c 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -649,11 +649,15 @@ static inline size_t cpumask_size(void)
  * used. Please use this_cpu_cpumask_var_t in those cases. The direct use
  * of this_cpu_ptr() or this_cpu_read() will lead to failures when the
  * other type of cpumask_var_t implementation is configured.
+ *
+ * Please also note that __cpumask_var_read_mostly can be used to declare
+ * a cpumask_var_t variable itself (not its content) as read mostly.
  */
 #ifdef CONFIG_CPUMASK_OFFSTACK
 typedef struct cpumask *cpumask_var_t;
 
-#define this_cpu_cpumask_var_ptr(x) this_cpu_read(x)
+#define this_cpu_cpumask_var_ptr(x)	this_cpu_read(x)
+#define __cpumask_var_read_mostly	__read_mostly
 
 bool alloc_cpumask_var_node(cpumask_var_t *mask, gfp_t flags, int node);
 bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags);
@@ -667,6 +671,7 @@ void free_bootmem_cpumask_var(cpumask_var_t mask);
 typedef struct cpumask cpumask_var_t[1];
 
 #define this_cpu_cpumask_var_ptr(x) this_cpu_ptr(x)
+#define __cpumask_var_read_mostly
 
 static inline bool alloc_cpumask_var(cpumask_var_t *mask, gfp_t flags)
 {
diff --git a/include/linux/delay.h b/include/linux/delay.h
index a6ecb34cf547..2ecb3c46b20a 100644
--- a/include/linux/delay.h
+++ b/include/linux/delay.h
@@ -5,6 +5,17 @@
  * Copyright (C) 1993 Linus Torvalds
  *
  * Delay routines, using a pre-computed "loops_per_jiffy" value.
+ *
+ * Please note that ndelay(), udelay() and mdelay() may return early for
+ * several reasons:
+ *  1. computed loops_per_jiffy too low (due to the time taken to
+ *     execute the timer interrupt.)
+ *  2. cache behaviour affecting the time it takes to execute the
+ *     loop function.
+ *  3. CPU clock rate changes.
+ *
+ * Please see this thread:
+ *   http://lists.openwall.net/linux-kernel/2011/01/09/56
  */
 
 #include <linux/kernel.h>
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index cdab81ba29f8..e52b427223ba 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -88,12 +88,6 @@ enum hrtimer_restart {
  * @base:	pointer to the timer base (per cpu and per clock)
  * @state:	state information (See bit values above)
  * @is_rel:	Set if the timer was armed relative
- * @start_pid:  timer statistics field to store the pid of the task which
- *		started the timer
- * @start_site:	timer statistics field to store the site where the timer
- *		was started
- * @start_comm: timer statistics field to store the name of the process which
- *		started the timer
  *
  * The hrtimer structure must be initialized by hrtimer_init()
  */
@@ -104,11 +98,6 @@ struct hrtimer {
 	struct hrtimer_clock_base	*base;
 	u8				state;
 	u8				is_rel;
-#ifdef CONFIG_TIMER_STATS
-	int				start_pid;
-	void				*start_site;
-	char				start_comm[16];
-#endif
 };
 
 /**
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 325f649d77ff..3a85d61f7614 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -42,6 +42,27 @@ extern struct fs_struct init_fs;
 #define INIT_PREV_CPUTIME(x)
 #endif
 
+#ifdef CONFIG_POSIX_TIMERS
+#define INIT_POSIX_TIMERS(s)						\
+	.posix_timers = LIST_HEAD_INIT(s.posix_timers),
+#define INIT_CPU_TIMERS(s)						\
+	.cpu_timers = {							\
+		LIST_HEAD_INIT(s.cpu_timers[0]),			\
+		LIST_HEAD_INIT(s.cpu_timers[1]),			\
+		LIST_HEAD_INIT(s.cpu_timers[2]),								\
+	},
+#define INIT_CPUTIMER(s)						\
+	.cputimer	= { 						\
+		.cputime_atomic	= INIT_CPUTIME_ATOMIC,			\
+		.running	= false,				\
+		.checking_timer = false,				\
+	},
+#else
+#define INIT_POSIX_TIMERS(s)
+#define INIT_CPU_TIMERS(s)
+#define INIT_CPUTIMER(s)
+#endif
+
 #define INIT_SIGNALS(sig) {						\
 	.nr_threads	= 1,						\
 	.thread_head	= LIST_HEAD_INIT(init_task.thread_node),	\
@@ -49,14 +70,10 @@ extern struct fs_struct init_fs;
 	.shared_pending	= { 						\
 		.list = LIST_HEAD_INIT(sig.shared_pending.list),	\
 		.signal =  {{0}}},					\
-	.posix_timers	 = LIST_HEAD_INIT(sig.posix_timers),		\
-	.cpu_timers	= INIT_CPU_TIMERS(sig.cpu_timers),		\
+	INIT_POSIX_TIMERS(sig)						\
+	INIT_CPU_TIMERS(sig)						\
 	.rlim		= INIT_RLIMITS,					\
-	.cputimer	= { 						\
-		.cputime_atomic	= INIT_CPUTIME_ATOMIC,			\
-		.running	= false,				\
-		.checking_timer = false,				\
-	},								\
+	INIT_CPUTIMER(sig)						\
 	INIT_PREV_CPUTIME(sig)						\
 	.cred_guard_mutex =						\
 		 __MUTEX_INITIALIZER(sig.cred_guard_mutex),		\
@@ -247,7 +264,7 @@ extern struct task_group root_task_group;
 	.blocked	= {{0}},					\
 	.alloc_lock	= __SPIN_LOCK_UNLOCKED(tsk.alloc_lock),		\
 	.journal_info	= NULL,						\
-	.cpu_timers	= INIT_CPU_TIMERS(tsk.cpu_timers),		\
+	INIT_CPU_TIMERS(tsk)						\
 	.pi_lock	= __RAW_SPIN_LOCK_UNLOCKED(tsk.pi_lock),	\
 	.timer_slack_ns = 50000, /* 50 usec default slack */		\
 	.pids = {							\
@@ -274,13 +291,6 @@ extern struct task_group root_task_group;
 }
 
 
-#define INIT_CPU_TIMERS(cpu_timers)					\
-{									\
-	LIST_HEAD_INIT(cpu_timers[0]),					\
-	LIST_HEAD_INIT(cpu_timers[1]),					\
-	LIST_HEAD_INIT(cpu_timers[2]),					\
-}
-
 /* Attach to the init_task data structure for proper alignment */
 #define __init_task_data __attribute__((__section__(".data..init_task")))
 
diff --git a/include/linux/math64.h b/include/linux/math64.h
index 6e8b5b270ffe..80690c96c734 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -133,6 +133,16 @@ __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
 	return ret;
 }
 
+#ifndef mul_u32_u32
+/*
+ * Many a GCC version messes this up and generates a 64x64 mult :-(
+ */
+static inline u64 mul_u32_u32(u32 a, u32 b)
+{
+	return (u64)a * b;
+}
+#endif
+
 #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
 
 #ifndef mul_u64_u32_shr
@@ -160,9 +170,9 @@ static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift)
 	al = a;
 	ah = a >> 32;
 
-	ret = ((u64)al * mul) >> shift;
+	ret = mul_u32_u32(al, mul) >> shift;
 	if (ah)
-		ret += ((u64)ah * mul) << (32 - shift);
+		ret += mul_u32_u32(ah, mul) << (32 - shift);
 
 	return ret;
 }
@@ -186,10 +196,10 @@ static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift)
 	a0.ll = a;
 	b0.ll = b;
 
-	rl.ll = (u64)a0.l.low * b0.l.low;
-	rm.ll = (u64)a0.l.low * b0.l.high;
-	rn.ll = (u64)a0.l.high * b0.l.low;
-	rh.ll = (u64)a0.l.high * b0.l.high;
+	rl.ll = mul_u32_u32(a0.l.low, b0.l.low);
+	rm.ll = mul_u32_u32(a0.l.low, b0.l.high);
+	rn.ll = mul_u32_u32(a0.l.high, b0.l.low);
+	rh.ll = mul_u32_u32(a0.l.high, b0.l.high);
 
 	/*
 	 * Each of these lines computes a 64-bit intermediate result into "c",
@@ -229,8 +239,8 @@ static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor)
 	} u, rl, rh;
 
 	u.ll = a;
-	rl.ll = (u64)u.l.low * mul;
-	rh.ll = (u64)u.l.high * mul + rl.l.high;
+	rl.ll = mul_u32_u32(u.l.low, mul);
+	rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high;
 
 	/* Bits 32-63 of the result will be in rh.l.low. */
 	rl.l.high = do_div(rh.ll, divisor);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ad3ec9ec61f7..6e4782eae076 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -734,13 +734,14 @@ struct signal_struct {
 	unsigned int		is_child_subreaper:1;
 	unsigned int		has_child_subreaper:1;
 
+#ifdef CONFIG_POSIX_TIMERS
+
 	/* POSIX.1b Interval Timers */
 	int			posix_timer_id;
 	struct list_head	posix_timers;
 
 	/* ITIMER_REAL timer for the process */
 	struct hrtimer real_timer;
-	struct pid *leader_pid;
 	ktime_t it_real_incr;
 
 	/*
@@ -759,12 +760,16 @@ struct signal_struct {
 	/* Earliest-expiration cache. */
 	struct task_cputime cputime_expires;
 
+	struct list_head cpu_timers[3];
+
+#endif
+
+	struct pid *leader_pid;
+
 #ifdef CONFIG_NO_HZ_FULL
 	atomic_t tick_dep_mask;
 #endif
 
-	struct list_head cpu_timers[3];
-
 	struct pid *tty_old_pgrp;
 
 	/* boolean value for session group leader */
@@ -1691,8 +1696,10 @@ struct task_struct {
 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
 	unsigned long min_flt, maj_flt;
 
+#ifdef CONFIG_POSIX_TIMERS
 	struct task_cputime cputime_expires;
 	struct list_head cpu_timers[3];
+#endif
 
 /* process credentials */
 	const struct cred __rcu *ptracer_cred; /* Tracer's credentials at attach */
diff --git a/include/linux/timer.h b/include/linux/timer.h
index 51d601f192d4..5a209b84fd9e 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -20,11 +20,6 @@ struct timer_list {
 	unsigned long		data;
 	u32			flags;
 
-#ifdef CONFIG_TIMER_STATS
-	int			start_pid;
-	void			*start_site;
-	char			start_comm[16];
-#endif
 #ifdef CONFIG_LOCKDEP
 	struct lockdep_map	lockdep_map;
 #endif
@@ -197,46 +192,6 @@ extern int mod_timer_pending(struct timer_list *timer, unsigned long expires);
  */
 #define NEXT_TIMER_MAX_DELTA	((1UL << 30) - 1)
 
-/*
- * Timer-statistics info:
- */
-#ifdef CONFIG_TIMER_STATS
-
-extern int timer_stats_active;
-
-extern void init_timer_stats(void);
-
-extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
-				     void *timerf, char *comm, u32 flags);
-
-extern void __timer_stats_timer_set_start_info(struct timer_list *timer,
-					       void *addr);
-
-static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
-{
-	if (likely(!timer_stats_active))
-		return;
-	__timer_stats_timer_set_start_info(timer, __builtin_return_address(0));
-}
-
-static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
-{
-	timer->start_site = NULL;
-}
-#else
-static inline void init_timer_stats(void)
-{
-}
-
-static inline void timer_stats_timer_set_start_info(struct timer_list *timer)
-{
-}
-
-static inline void timer_stats_timer_clear_start_info(struct timer_list *timer)
-{
-}
-#endif
-
 extern void add_timer(struct timer_list *timer);
 
 extern int try_to_del_timer_sync(struct timer_list *timer);