Merge branch 'timers-timekeeping-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'timers-timekeeping-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  um: Fix read_persistent_clock fallout
  kgdb: Do not access xtime directly
  powerpc: Clean up obsolete code relating to decrementer and timebase
  powerpc: Rework VDSO gettimeofday to prevent time going backwards
  clocksource: Add __clocksource_updatefreq_hz/khz methods
  x86: Convert common clocksources to use clocksource_register_hz/khz
  timekeeping: Make xtime and wall_to_monotonic static
  hrtimer: Cleanup direct access to wall_to_monotonic
  um: Convert to use read_persistent_clock
  timkeeping: Fix update_vsyscall to provide wall_to_monotonic offset
  powerpc: Cleanup xtime usage
  powerpc: Simplify update_vsyscall
  time: Kill off CONFIG_GENERIC_TIME
  time: Implement timespec_add
  x86: Fix vtime/file timestamp inconsistencies

Trivial conflicts in Documentation/feature-removal-schedule.txt

Much less trivial conflicts in arch/powerpc/kernel/time.c resolved as
per Thomas' earlier merge commit 47916be4e28c ("Merge branch
'powerpc.cherry-picks' into timers/clocksource")

Documentation/feature-removal-schedule.txt

@@ -445,16 +445,6 @@ Who:	Jan Kiszka <jan.kiszka@web.de>
 
 ----------------------------
 
-What:	xtime, wall_to_monotonic
-When:	2.6.36+
-Files:	kernel/time/timekeeping.c include/linux/time.h
-Why:	Cleaning up timekeeping internal values. Please use
-	existing timekeeping accessor functions to access
-	the equivalent functionality.
-Who:	John Stultz <johnstul@us.ibm.com>
-
-----------------------------
-
 What:	KVM paravirt mmu host support
 When:	January 2011
 Why:	The paravirt mmu host support is slower than non-paravirt mmu, both

Documentation/kernel-parameters.txt

@@ -73,7 +73,6 @@ parameter is applicable:
 	MTD	MTD (Memory Technology Device) support is enabled.
 	NET	Appropriate network support is enabled.
 	NUMA	NUMA support is enabled.
-	GENERIC_TIME The generic timeofday code is enabled.
 	NFS	Appropriate NFS support is enabled.
 	OSS	OSS sound support is enabled.
 	PV_OPS	A paravirtualized kernel is enabled.
@@ -470,7 +469,7 @@ and is between 256 and 4096 characters. It is defined in the file
 			clocksource is not available, it defaults to PIT.
 			Format: { pit | tsc | cyclone | pmtmr }
 
-	clocksource=	[GENERIC_TIME] Override the default clocksource
+	clocksource=	Override the default clocksource
 			Format: <string>
 			Override the default clocksource and use the clocksource
 			with the name specified.

arch/alpha/Kconfig

@@ -47,10 +47,6 @@ config GENERIC_CALIBRATE_DELAY
 	bool
 	default y
 
-config GENERIC_TIME
-	bool
-	default y
-
 config GENERIC_CMOS_UPDATE
         def_bool y
 

arch/arm/Kconfig

@@ -43,10 +43,6 @@ config SYS_SUPPORTS_APM_EMULATION
 config GENERIC_GPIO
 	bool
 
-config GENERIC_TIME
-	bool
-	default y
-
 config ARCH_USES_GETTIMEOFFSET
 	bool
 	default n

arch/avr32/Kconfig

@@ -45,9 +45,6 @@ config GENERIC_IRQ_PROBE
 config RWSEM_GENERIC_SPINLOCK
 	def_bool y
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_CLOCKEVENTS
 	def_bool y
 

arch/blackfin/Kconfig

@@ -614,9 +614,6 @@ comment "Kernel Timer/Scheduler"
 
 source kernel/Kconfig.hz
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_CLOCKEVENTS
 	bool "Generic clock events"
 	default y

arch/cris/Kconfig

@@ -20,9 +20,6 @@ config RWSEM_GENERIC_SPINLOCK
 config RWSEM_XCHGADD_ALGORITHM
 	bool
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_CMOS_UPDATE
 	def_bool y
 

arch/frv/Kconfig

@@ -40,10 +40,6 @@ config GENERIC_HARDIRQS_NO__DO_IRQ
 	bool
 	default y
 
-config GENERIC_TIME
-	bool
-	default y
-
 config TIME_LOW_RES
 	bool
 	default y

arch/h8300/Kconfig

@@ -62,10 +62,6 @@ config GENERIC_CALIBRATE_DELAY
 	bool
 	default y
 
-config GENERIC_TIME
-	bool
-	default y
-
 config GENERIC_BUG
         bool
         depends on BUG

arch/ia64/Kconfig

@@ -82,10 +82,6 @@ config GENERIC_CALIBRATE_DELAY
 	bool
 	default y
 
-config GENERIC_TIME
-	bool
-	default y
-
 config GENERIC_TIME_VSYSCALL
 	bool
 	default y

arch/ia64/kernel/time.c

@@ -471,7 +471,8 @@ void update_vsyscall_tz(void)
 {
 }
 
-void update_vsyscall(struct timespec *wall, struct clocksource *c, u32 mult)
+void update_vsyscall(struct timespec *wall, struct timespec *wtm,
+			struct clocksource *c, u32 mult)
 {
         unsigned long flags;
 
@@ -487,9 +488,9 @@ void update_vsyscall(struct timespec *wall, struct clocksource *c, u32 mult)
 	/* copy kernel time structures */
         fsyscall_gtod_data.wall_time.tv_sec = wall->tv_sec;
         fsyscall_gtod_data.wall_time.tv_nsec = wall->tv_nsec;
-        fsyscall_gtod_data.monotonic_time.tv_sec = wall_to_monotonic.tv_sec
+	fsyscall_gtod_data.monotonic_time.tv_sec = wtm->tv_sec
 							+ wall->tv_sec;
-        fsyscall_gtod_data.monotonic_time.tv_nsec = wall_to_monotonic.tv_nsec
+	fsyscall_gtod_data.monotonic_time.tv_nsec = wtm->tv_nsec
 							+ wall->tv_nsec;
 
 	/* normalize */

arch/m32r/Kconfig

@@ -44,9 +44,6 @@ config HZ
 	int
 	default 100
 
-config GENERIC_TIME
-	def_bool y
-
 config ARCH_USES_GETTIMEOFFSET
 	def_bool y
 

arch/m68k/Kconfig

@@ -59,9 +59,6 @@ config HZ
 	int
 	default 100
 
-config GENERIC_TIME
-	def_bool y
-
 config ARCH_USES_GETTIMEOFFSET
 	def_bool y
 

arch/m68knommu/Kconfig

@@ -63,10 +63,6 @@ config GENERIC_CALIBRATE_DELAY
 	bool
 	default y
 
-config GENERIC_TIME
-	bool
-	default y
-
 config GENERIC_CMOS_UPDATE
 	bool
 	default y

arch/microblaze/Kconfig

@@ -51,9 +51,6 @@ config GENERIC_IRQ_PROBE
 config GENERIC_CALIBRATE_DELAY
 	def_bool y
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_TIME_VSYSCALL
 	def_bool n
 

arch/mips/Kconfig

@@ -758,10 +758,6 @@ config GENERIC_CLOCKEVENTS
 	bool
 	default y
 
-config GENERIC_TIME
-	bool
-	default y
-
 config GENERIC_CMOS_UPDATE
 	bool
 	default y

arch/mn10300/Kconfig

@@ -46,9 +46,6 @@ config GENERIC_FIND_NEXT_BIT
 config GENERIC_HWEIGHT
 	def_bool y
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_BUG
 	def_bool y
 

arch/parisc/Kconfig

@@ -66,10 +66,6 @@ config GENERIC_CALIBRATE_DELAY
 	bool
 	default y
 
-config GENERIC_TIME
-	bool
-	default y
-
 config TIME_LOW_RES
 	bool
 	depends on SMP

arch/powerpc/Kconfig

@@ -29,9 +29,6 @@ config MMU
 config GENERIC_CMOS_UPDATE
 	def_bool y
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_TIME_VSYSCALL
 	def_bool y
 

arch/powerpc/kernel/time.c

@@ -796,10 +796,30 @@ static cycle_t timebase_read(struct clocksource *cs)
 	return (cycle_t)get_tb();
 }
 
-static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
-			       u64 new_tb_to_xs, struct timespec *now,
-			       u32 frac_sec)
+void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
+			struct clocksource *clock, u32 mult)
 {
+	u64 new_tb_to_xs, new_stamp_xsec;
+	u32 frac_sec;
+
+	if (clock != &clocksource_timebase)
+		return;
+
+	/* Make userspace gettimeofday spin until we're done. */
+	++vdso_data->tb_update_count;
+	smp_mb();
+
+	/* XXX this assumes clock->shift == 22 */
+	/* 4611686018 ~= 2^(20+64-22) / 1e9 */
+	new_tb_to_xs = (u64) mult * 4611686018ULL;
+	new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
+	do_div(new_stamp_xsec, 1000000000);
+	new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
+
+	BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
+	/* this is tv_nsec / 1e9 as a 0.32 fraction */
+	frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
+
 	/*
 	 * tb_update_count is used to allow the userspace gettimeofday code
 	 * to assure itself that it sees a consistent view of the tb_to_xs and
@@ -811,43 +831,17 @@ static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
 	 * We expect the caller to have done the first increment of
 	 * vdso_data->tb_update_count already.
 	 */
-	vdso_data->tb_orig_stamp = new_tb_stamp;
+	vdso_data->tb_orig_stamp = clock->cycle_last;
 	vdso_data->stamp_xsec = new_stamp_xsec;
 	vdso_data->tb_to_xs = new_tb_to_xs;
-	vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
-	vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
-	vdso_data->stamp_xtime = *now;
+	vdso_data->wtom_clock_sec = wtm->tv_sec;
+	vdso_data->wtom_clock_nsec = wtm->tv_nsec;
+	vdso_data->stamp_xtime = *wall_time;
 	vdso_data->stamp_sec_fraction = frac_sec;
 	smp_wmb();
 	++(vdso_data->tb_update_count);
 }
 
-void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
-		     u32 mult)
-{
-	u64 t2x, stamp_xsec;
-	u32 frac_sec;
-
-	if (clock != &clocksource_timebase)
-		return;
-
-	/* Make userspace gettimeofday spin until we're done. */
-	++vdso_data->tb_update_count;
-	smp_mb();
-
-	/* XXX this assumes clock->shift == 22 */
-	/* 4611686018 ~= 2^(20+64-22) / 1e9 */
-	t2x = (u64) mult * 4611686018ULL;
-	stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
-	do_div(stamp_xsec, 1000000000);
-	stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
-
-	BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
-	/* this is tv_nsec / 1e9 as a 0.32 fraction */
-	frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
-	update_gtod(clock->cycle_last, stamp_xsec, t2x, wall_time, frac_sec);
-}
-
 void update_vsyscall_tz(void)
 {
 	/* Make userspace gettimeofday spin until we're done. */

arch/s390/Kconfig

@@ -40,9 +40,6 @@ config ARCH_HAS_ILOG2_U64
 config GENERIC_HWEIGHT
 	def_bool y
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_TIME_VSYSCALL
 	def_bool y
 

arch/s390/kernel/time.c

@@ -207,8 +207,8 @@ struct clocksource * __init clocksource_default_clock(void)
 	return &clocksource_tod;
 }
 
-void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
-		     u32 mult)
+void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
+			struct clocksource *clock, u32 mult)
 {
 	if (clock != &clocksource_tod)
 		return;
@@ -219,8 +219,8 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
 	vdso_data->xtime_tod_stamp = clock->cycle_last;
 	vdso_data->xtime_clock_sec = wall_time->tv_sec;
 	vdso_data->xtime_clock_nsec = wall_time->tv_nsec;
-	vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
-	vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
+	vdso_data->wtom_clock_sec = wtm->tv_sec;
+	vdso_data->wtom_clock_nsec = wtm->tv_nsec;
 	vdso_data->ntp_mult = mult;
 	smp_wmb();
 	++vdso_data->tb_update_count;

arch/score/Kconfig

@@ -55,9 +55,6 @@ config GENERIC_CALIBRATE_DELAY
 config GENERIC_CLOCKEVENTS
 	def_bool y
 
-config GENERIC_TIME
-	def_bool y
-
 config SCHED_NO_NO_OMIT_FRAME_POINTER
 	def_bool y
 

arch/sh/Kconfig

@@ -98,9 +98,6 @@ config GENERIC_CALIBRATE_DELAY
 config GENERIC_IOMAP
 	bool
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_CLOCKEVENTS
 	def_bool y
 

arch/sparc/Kconfig

@@ -67,9 +67,6 @@ config BITS
 	default 32 if SPARC32
 	default 64 if SPARC64
 
-config GENERIC_TIME
-	def_bool y
-
 config ARCH_USES_GETTIMEOFFSET
 	bool
 	default y if SPARC32

arch/um/Kconfig.common

@@ -55,10 +55,6 @@ config GENERIC_BUG
 	default y
 	depends on BUG
 
-config GENERIC_TIME
-	bool
-	default y
-
 config GENERIC_CLOCKEVENTS
 	bool
 	default y

arch/um/kernel/time.c

@@ -102,16 +102,16 @@ static void __init setup_itimer(void)
 	clockevents_register_device(&itimer_clockevent);
 }
 
-void __init time_init(void)
+void read_persistent_clock(struct timespec *ts)
 {
-	long long nsecs;
-
-	timer_init();
+	long long nsecs = os_nsecs();
 
-	nsecs = os_nsecs();
-	set_normalized_timespec(&wall_to_monotonic, -nsecs / NSEC_PER_SEC,
-				-nsecs % NSEC_PER_SEC);
-	set_normalized_timespec(&xtime, nsecs / NSEC_PER_SEC,
+	set_normalized_timespec(ts, nsecs / NSEC_PER_SEC,
 				nsecs % NSEC_PER_SEC);
+}
+
+void __init time_init(void)
+{
+	timer_init();
 	late_time_init = setup_itimer;
 }

arch/x86/Kconfig

@@ -73,9 +73,6 @@ config ARCH_DEFCONFIG
 	default "arch/x86/configs/i386_defconfig" if X86_32
 	default "arch/x86/configs/x86_64_defconfig" if X86_64
 
-config GENERIC_TIME
-	def_bool y
-
 config GENERIC_CMOS_UPDATE
 	def_bool y
 
@@ -2047,7 +2044,7 @@ config SCx200
 
 config SCx200HR_TIMER
 	tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
-	depends on SCx200 && GENERIC_TIME
+	depends on SCx200
 	default y
 	---help---
 	  This driver provides a clocksource built upon the on-chip

arch/x86/kernel/hpet.c

@@ -16,7 +16,6 @@
 #include <asm/hpet.h>
 
 #define HPET_MASK			CLOCKSOURCE_MASK(32)
-#define HPET_SHIFT			22
 
 /* FSEC = 10^-15
    NSEC = 10^-9 */
@@ -787,7 +786,6 @@ static struct clocksource clocksource_hpet = {
 	.rating		= 250,
 	.read		= read_hpet,
 	.mask		= HPET_MASK,
-	.shift		= HPET_SHIFT,
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
 	.resume		= hpet_resume_counter,
 #ifdef CONFIG_X86_64
@@ -798,6 +796,7 @@ static struct clocksource clocksource_hpet = {
 static int hpet_clocksource_register(void)
 {
 	u64 start, now;
+	u64 hpet_freq;
 	cycle_t t1;
 
 	/* Start the counter */
@@ -832,9 +831,15 @@ static int hpet_clocksource_register(void)
 	 *  mult = (hpet_period * 2^shift)/10^6
 	 *  mult = (hpet_period << shift)/FSEC_PER_NSEC
 	 */
-	clocksource_hpet.mult = div_sc(hpet_period, FSEC_PER_NSEC, HPET_SHIFT);
 
-	clocksource_register(&clocksource_hpet);
+	/* Need to convert hpet_period (fsec/cyc) to cyc/sec:
+	 *
+	 * cyc/sec = FSEC_PER_SEC/hpet_period(fsec/cyc)
+	 * cyc/sec = (FSEC_PER_NSEC * NSEC_PER_SEC)/hpet_period
+	 */
+	hpet_freq = FSEC_PER_NSEC * NSEC_PER_SEC;
+	do_div(hpet_freq, hpet_period);
+	clocksource_register_hz(&clocksource_hpet, (u32)hpet_freq);
 
 	return 0;
 }

arch/x86/kernel/tsc.c

@@ -751,7 +751,6 @@ static struct clocksource clocksource_tsc = {
 	.read                   = read_tsc,
 	.resume			= resume_tsc,
 	.mask                   = CLOCKSOURCE_MASK(64),
-	.shift                  = 22,
 	.flags                  = CLOCK_SOURCE_IS_CONTINUOUS |
 				  CLOCK_SOURCE_MUST_VERIFY,
 #ifdef CONFIG_X86_64
@@ -845,8 +844,6 @@ __cpuinit int unsynchronized_tsc(void)
 
 static void __init init_tsc_clocksource(void)
 {
-	clocksource_tsc.mult = clocksource_khz2mult(tsc_khz,
-			clocksource_tsc.shift);
 	if (tsc_clocksource_reliable)
 		clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
 	/* lower the rating if we already know its unstable: */
@@ -854,7 +851,7 @@ static void __init init_tsc_clocksource(void)
 		clocksource_tsc.rating = 0;
 		clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
 	}
-	clocksource_register(&clocksource_tsc);
+	clocksource_register_khz(&clocksource_tsc, tsc_khz);
 }
 
 #ifdef CONFIG_X86_64

arch/x86/kernel/vsyscall_64.c

@@ -73,8 +73,8 @@ void update_vsyscall_tz(void)
 	write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
 }
 
-void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
-		     u32 mult)
+void update_vsyscall(struct timespec *wall_time, struct timespec *wtm,
+			struct clocksource *clock, u32 mult)
 {
 	unsigned long flags;
 
@@ -87,7 +87,7 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
 	vsyscall_gtod_data.clock.shift = clock->shift;
 	vsyscall_gtod_data.wall_time_sec = wall_time->tv_sec;
 	vsyscall_gtod_data.wall_time_nsec = wall_time->tv_nsec;
-	vsyscall_gtod_data.wall_to_monotonic = wall_to_monotonic;
+	vsyscall_gtod_data.wall_to_monotonic = *wtm;
 	vsyscall_gtod_data.wall_time_coarse = __current_kernel_time();
 	write_sequnlock_irqrestore(&vsyscall_gtod_data.lock, flags);
 }
@@ -169,13 +169,18 @@ int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz)
  * unlikely */
 time_t __vsyscall(1) vtime(time_t *t)
 {
-	struct timeval tv;
+	unsigned seq;
 	time_t result;
 	if (unlikely(!__vsyscall_gtod_data.sysctl_enabled))
 		return time_syscall(t);
 
-	vgettimeofday(&tv, NULL);
-	result = tv.tv_sec;
+	do {
+		seq = read_seqbegin(&__vsyscall_gtod_data.lock);
+
+		result = __vsyscall_gtod_data.wall_time_sec;
+
+	} while (read_seqretry(&__vsyscall_gtod_data.lock, seq));
+
 	if (t)
 		*t = result;
 	return result;

arch/xtensa/Kconfig

@@ -48,9 +48,6 @@ config HZ
 	int
 	default 100
 
-config GENERIC_TIME
-	def_bool y
-
 source "init/Kconfig"
 source "kernel/Kconfig.freezer"
 

drivers/Makefile

@@ -101,7 +101,9 @@ obj-y				+= firmware/
 obj-$(CONFIG_CRYPTO)		+= crypto/
 obj-$(CONFIG_SUPERH)		+= sh/
 obj-$(CONFIG_ARCH_SHMOBILE)	+= sh/
-obj-$(CONFIG_GENERIC_TIME)	+= clocksource/
+ifndef CONFIG_ARCH_USES_GETTIMEOFFSET
+obj-y				+= clocksource/
+endif
 obj-$(CONFIG_DMA_ENGINE)	+= dma/
 obj-$(CONFIG_DCA)		+= dca/
 obj-$(CONFIG_HID)		+= hid/

drivers/acpi/acpi_pad.c

@@ -77,7 +77,7 @@ static void power_saving_mwait_init(void)
 	power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
 		(highest_subcstate - 1);
 
-#if defined(CONFIG_GENERIC_TIME) && defined(CONFIG_X86)
+#if defined(CONFIG_X86)
 	switch (boot_cpu_data.x86_vendor) {
 	case X86_VENDOR_AMD:
 	case X86_VENDOR_INTEL:

drivers/acpi/processor_idle.c

@@ -264,7 +264,7 @@ int acpi_processor_resume(struct acpi_device * device)
 	return 0;
 }
 
-#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86)
+#if defined(CONFIG_X86)
 static void tsc_check_state(int state)
 {
 	switch (boot_cpu_data.x86_vendor) {

drivers/clocksource/acpi_pm.c

@@ -68,10 +68,7 @@ static struct clocksource clocksource_acpi_pm = {
 	.rating		= 200,
 	.read		= acpi_pm_read,
 	.mask		= (cycle_t)ACPI_PM_MASK,
-	.mult		= 0, /*to be calculated*/
-	.shift		= 22,
 	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
-
 };
 
 
@@ -190,9 +187,6 @@ static int __init init_acpi_pm_clocksource(void)
 	if (!pmtmr_ioport)
 		return -ENODEV;
 
-	clocksource_acpi_pm.mult = clocksource_hz2mult(PMTMR_TICKS_PER_SEC,
-						clocksource_acpi_pm.shift);
-
 	/* "verify" this timing source: */
 	for (j = 0; j < ACPI_PM_MONOTONICITY_CHECKS; j++) {
 		udelay(100 * j);
@@ -220,7 +214,8 @@ static int __init init_acpi_pm_clocksource(void)
 	if (verify_pmtmr_rate() != 0)
 		return -ENODEV;
 
-	return clocksource_register(&clocksource_acpi_pm);
+	return clocksource_register_hz(&clocksource_acpi_pm,
+						PMTMR_TICKS_PER_SEC);
 }
 
 /* We use fs_initcall because we want the PCI fixups to have run

drivers/misc/Kconfig

@@ -72,7 +72,7 @@ config ATMEL_TCLIB
 
 config ATMEL_TCB_CLKSRC
 	bool "TC Block Clocksource"
-	depends on ATMEL_TCLIB && GENERIC_TIME
+	depends on ATMEL_TCLIB
 	default y
 	help
 	  Select this to get a high precision clocksource based on a
@@ -240,7 +240,7 @@ config CS5535_MFGPT_DEFAULT_IRQ
 
 config CS5535_CLOCK_EVENT_SRC
 	tristate "CS5535/CS5536 high-res timer (MFGPT) events"
-	depends on GENERIC_TIME && GENERIC_CLOCKEVENTS && CS5535_MFGPT
+	depends on GENERIC_CLOCKEVENTS && CS5535_MFGPT
 	help
 	  This driver provides a clock event source based on the MFGPT
 	  timer(s) in the CS5535 and CS5536 companion chips.

include/linux/clocksource.h

@@ -292,6 +292,8 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec);
  */
 extern int
 __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq);
+extern void
+__clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq);
 
 static inline int clocksource_register_hz(struct clocksource *cs, u32 hz)
 {
@@ -303,6 +305,15 @@ static inline int clocksource_register_khz(struct clocksource *cs, u32 khz)
 	return __clocksource_register_scale(cs, 1000, khz);
 }
 
+static inline void __clocksource_updatefreq_hz(struct clocksource *cs, u32 hz)
+{
+	__clocksource_updatefreq_scale(cs, 1, hz);
+}
+
+static inline void __clocksource_updatefreq_khz(struct clocksource *cs, u32 khz)
+{
+	__clocksource_updatefreq_scale(cs, 1000, khz);
+}
 
 static inline void
 clocksource_calc_mult_shift(struct clocksource *cs, u32 freq, u32 minsec)
@@ -313,11 +324,13 @@ clocksource_calc_mult_shift(struct clocksource *cs, u32 freq, u32 minsec)
 
 #ifdef CONFIG_GENERIC_TIME_VSYSCALL
 extern void
-update_vsyscall(struct timespec *ts, struct clocksource *c, u32 mult);
+update_vsyscall(struct timespec *ts, struct timespec *wtm,
+			struct clocksource *c, u32 mult);
 extern void update_vsyscall_tz(void);
 #else
 static inline void
-update_vsyscall(struct timespec *ts, struct clocksource *c, u32 mult)
+update_vsyscall(struct timespec *ts, struct timespec *wtm,
+			struct clocksource *c, u32 mult)
 {
 }
 

include/linux/time.h

@@ -76,9 +76,25 @@ extern unsigned long mktime(const unsigned int year, const unsigned int mon,
 			    const unsigned int min, const unsigned int sec);
 
 extern void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec);
+
+/*
+ * timespec_add_safe assumes both values are positive and checks
+ * for overflow. It will return TIME_T_MAX if the reutrn would be
+ * smaller then either of the arguments.
+ */
 extern struct timespec timespec_add_safe(const struct timespec lhs,
 					 const struct timespec rhs);
 
+
+static inline struct timespec timespec_add(struct timespec lhs,
+						struct timespec rhs)
+{
+	struct timespec ts_delta;
+	set_normalized_timespec(&ts_delta, lhs.tv_sec + rhs.tv_sec,
+				lhs.tv_nsec + rhs.tv_nsec);
+	return ts_delta;
+}
+
 /*
  * sub = lhs - rhs, in normalized form
  */
@@ -97,8 +113,6 @@ static inline struct timespec timespec_sub(struct timespec lhs,
 #define timespec_valid(ts) \
 	(((ts)->tv_sec >= 0) && (((unsigned long) (ts)->tv_nsec) < NSEC_PER_SEC))
 
-extern struct timespec xtime;
-extern struct timespec wall_to_monotonic;
 extern seqlock_t xtime_lock;
 
 extern void read_persistent_clock(struct timespec *ts);
@@ -110,7 +124,8 @@ extern int timekeeping_suspended;
 
 unsigned long get_seconds(void);
 struct timespec current_kernel_time(void);
-struct timespec __current_kernel_time(void); /* does not hold xtime_lock */
+struct timespec __current_kernel_time(void); /* does not take xtime_lock */
+struct timespec __get_wall_to_monotonic(void); /* does not take xtime_lock */
 struct timespec get_monotonic_coarse(void);
 
 #define CURRENT_TIME		(current_kernel_time())

kernel/debug/kdb/kdb_main.c

@@ -2548,6 +2548,7 @@ static void kdb_sysinfo(struct sysinfo *val)
  */
 static int kdb_summary(int argc, const char **argv)
 {
+	struct timespec now;
 	struct kdb_tm tm;
 	struct sysinfo val;
 
@@ -2562,7 +2563,8 @@ static int kdb_summary(int argc, const char **argv)
 	kdb_printf("domainname %s\n", init_uts_ns.name.domainname);
 	kdb_printf("ccversion  %s\n", __stringify(CCVERSION));
 
-	kdb_gmtime(&xtime, &tm);
+	now = __current_kernel_time();
+	kdb_gmtime(&now, &tm);
 	kdb_printf("date       %04d-%02d-%02d %02d:%02d:%02d "
 		   "tz_minuteswest %d\n",
 		1900+tm.tm_year, tm.tm_mon+1, tm.tm_mday,

kernel/hrtimer.c

@@ -90,7 +90,7 @@ static void hrtimer_get_softirq_time(struct hrtimer_cpu_base *base)
 	do {
 		seq = read_seqbegin(&xtime_lock);
 		xts = __current_kernel_time();
-		tom = wall_to_monotonic;
+		tom = __get_wall_to_monotonic();
 	} while (read_seqretry(&xtime_lock, seq));
 
 	xtim = timespec_to_ktime(xts);
@@ -608,7 +608,7 @@ static int hrtimer_reprogram(struct hrtimer *timer,
 static void retrigger_next_event(void *arg)
 {
 	struct hrtimer_cpu_base *base;
-	struct timespec realtime_offset;
+	struct timespec realtime_offset, wtm;
 	unsigned long seq;
 
 	if (!hrtimer_hres_active())
@@ -616,10 +616,9 @@ static void retrigger_next_event(void *arg)
 
 	do {
 		seq = read_seqbegin(&xtime_lock);
-		set_normalized_timespec(&realtime_offset,
-					-wall_to_monotonic.tv_sec,
-					-wall_to_monotonic.tv_nsec);
+		wtm = __get_wall_to_monotonic();
 	} while (read_seqretry(&xtime_lock, seq));
+	set_normalized_timespec(&realtime_offset, -wtm.tv_sec, -wtm.tv_nsec);
 
 	base = &__get_cpu_var(hrtimer_bases);
 

kernel/time.c

@@ -300,22 +300,6 @@ struct timespec timespec_trunc(struct timespec t, unsigned gran)
 }
 EXPORT_SYMBOL(timespec_trunc);
 
-#ifndef CONFIG_GENERIC_TIME
-/*
- * Simulate gettimeofday using do_gettimeofday which only allows a timeval
- * and therefore only yields usec accuracy
- */
-void getnstimeofday(struct timespec *tv)
-{
-	struct timeval x;
-
-	do_gettimeofday(&x);
-	tv->tv_sec = x.tv_sec;
-	tv->tv_nsec = x.tv_usec * NSEC_PER_USEC;
-}
-EXPORT_SYMBOL_GPL(getnstimeofday);
-#endif
-
 /* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
  * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
  * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.

kernel/time/Kconfig

@@ -6,7 +6,7 @@ config TICK_ONESHOT
 
 config NO_HZ
 	bool "Tickless System (Dynamic Ticks)"
-	depends on GENERIC_TIME && GENERIC_CLOCKEVENTS
+	depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
 	select TICK_ONESHOT
 	help
 	  This option enables a tickless system: timer interrupts will
@@ -15,7 +15,7 @@ config NO_HZ
 
 config HIGH_RES_TIMERS
 	bool "High Resolution Timer Support"
-	depends on GENERIC_TIME && GENERIC_CLOCKEVENTS
+	depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
 	select TICK_ONESHOT
 	help
 	  This option enables high resolution timer support. If your

kernel/time/clocksource.c

@@ -531,7 +531,7 @@ static u64 clocksource_max_deferment(struct clocksource *cs)
 	return max_nsecs - (max_nsecs >> 5);
 }
 
-#ifdef CONFIG_GENERIC_TIME
+#ifndef CONFIG_ARCH_USES_GETTIMEOFFSET
 
 /**
  * clocksource_select - Select the best clocksource available
@@ -577,7 +577,7 @@ static void clocksource_select(void)
 	}
 }
 
-#else /* CONFIG_GENERIC_TIME */
+#else /* !CONFIG_ARCH_USES_GETTIMEOFFSET */
 
 static inline void clocksource_select(void) { }
 
@@ -639,19 +639,18 @@ static void clocksource_enqueue(struct clocksource *cs)
 #define MAX_UPDATE_LENGTH 5 /* Seconds */
 
 /**
- * __clocksource_register_scale - Used to install new clocksources
+ * __clocksource_updatefreq_scale - Used update clocksource with new freq
  * @t:		clocksource to be registered
  * @scale:	Scale factor multiplied against freq to get clocksource hz
  * @freq:	clocksource frequency (cycles per second) divided by scale
  *
- * Returns -EBUSY if registration fails, zero otherwise.
+ * This should only be called from the clocksource->enable() method.
  *
  * This *SHOULD NOT* be called directly! Please use the
- * clocksource_register_hz() or clocksource_register_khz helper functions.
+ * clocksource_updatefreq_hz() or clocksource_updatefreq_khz helper functions.
  */
-int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
+void __clocksource_updatefreq_scale(struct clocksource *cs, u32 scale, u32 freq)
 {
-
 	/*
 	 * Ideally we want to use  some of the limits used in
 	 * clocksource_max_deferment, to provide a more informed
@@ -662,7 +661,27 @@ int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
 				      NSEC_PER_SEC/scale,
 				      MAX_UPDATE_LENGTH*scale);
 	cs->max_idle_ns = clocksource_max_deferment(cs);
+}
+EXPORT_SYMBOL_GPL(__clocksource_updatefreq_scale);
+
+/**
+ * __clocksource_register_scale - Used to install new clocksources
+ * @t:		clocksource to be registered
+ * @scale:	Scale factor multiplied against freq to get clocksource hz
+ * @freq:	clocksource frequency (cycles per second) divided by scale
+ *
+ * Returns -EBUSY if registration fails, zero otherwise.
+ *
+ * This *SHOULD NOT* be called directly! Please use the
+ * clocksource_register_hz() or clocksource_register_khz helper functions.
+ */
+int __clocksource_register_scale(struct clocksource *cs, u32 scale, u32 freq)
+{
+
+	/* Intialize mult/shift and max_idle_ns */
+	__clocksource_updatefreq_scale(cs, scale, freq);
 
+	/* Add clocksource to the clcoksource list */
 	mutex_lock(&clocksource_mutex);
 	clocksource_enqueue(cs);
 	clocksource_select();

kernel/time/timekeeping.c

@@ -153,8 +153,8 @@ __cacheline_aligned_in_smp DEFINE_SEQLOCK(xtime_lock);
  * - wall_to_monotonic is no longer the boot time, getboottime must be
  * used instead.
  */
-struct timespec xtime __attribute__ ((aligned (16)));
-struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
+static struct timespec xtime __attribute__ ((aligned (16)));
+static struct timespec wall_to_monotonic __attribute__ ((aligned (16)));
 static struct timespec total_sleep_time;
 
 /*
@@ -170,11 +170,10 @@ void timekeeping_leap_insert(int leapsecond)
 {
 	xtime.tv_sec += leapsecond;
 	wall_to_monotonic.tv_sec -= leapsecond;
-	update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult);
+	update_vsyscall(&xtime, &wall_to_monotonic, timekeeper.clock,
+			timekeeper.mult);
 }
 
-#ifdef CONFIG_GENERIC_TIME
-
 /**
  * timekeeping_forward_now - update clock to the current time
  *
@@ -328,7 +327,8 @@ int do_settimeofday(struct timespec *tv)
 	timekeeper.ntp_error = 0;
 	ntp_clear();
 
-	update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult);
+	update_vsyscall(&xtime, &wall_to_monotonic, timekeeper.clock,
+				timekeeper.mult);
 
 	write_sequnlock_irqrestore(&xtime_lock, flags);
 
@@ -376,52 +376,6 @@ void timekeeping_notify(struct clocksource *clock)
 	tick_clock_notify();
 }
 
-#else /* GENERIC_TIME */
-
-static inline void timekeeping_forward_now(void) { }
-
-/**
- * ktime_get - get the monotonic time in ktime_t format
- *
- * returns the time in ktime_t format
- */
-ktime_t ktime_get(void)
-{
-	struct timespec now;
-
-	ktime_get_ts(&now);
-
-	return timespec_to_ktime(now);
-}
-EXPORT_SYMBOL_GPL(ktime_get);
-
-/**
- * ktime_get_ts - get the monotonic clock in timespec format
- * @ts:		pointer to timespec variable
- *
- * The function calculates the monotonic clock from the realtime
- * clock and the wall_to_monotonic offset and stores the result
- * in normalized timespec format in the variable pointed to by @ts.
- */
-void ktime_get_ts(struct timespec *ts)
-{
-	struct timespec tomono;
-	unsigned long seq;
-
-	do {
-		seq = read_seqbegin(&xtime_lock);
-		getnstimeofday(ts);
-		tomono = wall_to_monotonic;
-
-	} while (read_seqretry(&xtime_lock, seq));
-
-	set_normalized_timespec(ts, ts->tv_sec + tomono.tv_sec,
-				ts->tv_nsec + tomono.tv_nsec);
-}
-EXPORT_SYMBOL_GPL(ktime_get_ts);
-
-#endif /* !GENERIC_TIME */
-
 /**
  * ktime_get_real - get the real (wall-) time in ktime_t format
  *
@@ -579,9 +533,9 @@ static int timekeeping_resume(struct sys_device *dev)
 
 	if (timespec_compare(&ts, &timekeeping_suspend_time) > 0) {
 		ts = timespec_sub(ts, timekeeping_suspend_time);
-		xtime = timespec_add_safe(xtime, ts);
+		xtime = timespec_add(xtime, ts);
 		wall_to_monotonic = timespec_sub(wall_to_monotonic, ts);
-		total_sleep_time = timespec_add_safe(total_sleep_time, ts);
+		total_sleep_time = timespec_add(total_sleep_time, ts);
 	}
 	/* re-base the last cycle value */
 	timekeeper.clock->cycle_last = timekeeper.clock->read(timekeeper.clock);
@@ -784,10 +738,11 @@ void update_wall_time(void)
 		return;
 
 	clock = timekeeper.clock;
-#ifdef CONFIG_GENERIC_TIME
-	offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
-#else
+
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
 	offset = timekeeper.cycle_interval;
+#else
+	offset = (clock->read(clock) - clock->cycle_last) & clock->mask;
 #endif
 	timekeeper.xtime_nsec = (s64)xtime.tv_nsec << timekeeper.shift;
 
@@ -856,7 +811,8 @@ void update_wall_time(void)
 	}
 
 	/* check to see if there is a new clocksource to use */
-	update_vsyscall(&xtime, timekeeper.clock, timekeeper.mult);
+	update_vsyscall(&xtime, &wall_to_monotonic, timekeeper.clock,
+				timekeeper.mult);
 }
 
 /**
@@ -887,7 +843,7 @@ EXPORT_SYMBOL_GPL(getboottime);
  */
 void monotonic_to_bootbased(struct timespec *ts)
 {
-	*ts = timespec_add_safe(*ts, total_sleep_time);
+	*ts = timespec_add(*ts, total_sleep_time);
 }
 EXPORT_SYMBOL_GPL(monotonic_to_bootbased);
 
@@ -902,6 +858,11 @@ struct timespec __current_kernel_time(void)
 	return xtime;
 }
 
+struct timespec __get_wall_to_monotonic(void)
+{
+	return wall_to_monotonic;
+}
+
 struct timespec current_kernel_time(void)
 {
 	struct timespec now;

kernel/trace/Kconfig

@@ -153,7 +153,7 @@ config IRQSOFF_TRACER
 	bool "Interrupts-off Latency Tracer"
 	default n
 	depends on TRACE_IRQFLAGS_SUPPORT
-	depends on GENERIC_TIME
+	depends on !ARCH_USES_GETTIMEOFFSET
 	select TRACE_IRQFLAGS
 	select GENERIC_TRACER
 	select TRACER_MAX_TRACE
@@ -175,7 +175,7 @@ config IRQSOFF_TRACER
 config PREEMPT_TRACER
 	bool "Preemption-off Latency Tracer"
 	default n
-	depends on GENERIC_TIME
+	depends on !ARCH_USES_GETTIMEOFFSET
 	depends on PREEMPT
 	select GENERIC_TRACER
 	select TRACER_MAX_TRACE