Pull ia64-clocksource into release branch

24 files changed, 335 insertions, 566 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 854744bde224..5fbe07706ae9 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1154,6 +1154,8 @@ and is between 256 and 4096 characters. It is defined in the file
 
         nointroute      [IA-64]
 
+        nojitter        [IA64] Disables jitter checking for ITC timers.
+
         nolapic         [IA-32,APIC] Do not enable or use the local APIC.
 
         nolapic_timer   [IA-32,APIC] Do not use the local APIC timer.
diff --git a/Documentation/time_interpolators.txt b/Documentation/time_interpolators.txt
deleted file mode 100644
index e3b60854fbc2..000000000000
--- a/Documentation/time_interpolators.txt
+++ /dev/null
@@ -1,41 +0,0 @@
-Time Interpolators
-------------------
-
-Time interpolators are a base of time calculation between timer ticks and
-allow an accurate determination of time down to the accuracy of the time
-source in nanoseconds.
-
-The architecture specific code typically provides gettimeofday and
-settimeofday under Linux. The time interpolator provides both if an arch
-defines CONFIG_TIME_INTERPOLATION. The arch still must set up timer tick
-operations and call the necessary functions to advance the clock.
-
-With the time interpolator a standardized interface exists for time
-interpolation between ticks. The provided logic is highly scalable
-and has been tested in SMP situations of up to 512 CPUs.
-
-If CONFIG_TIME_INTERPOLATION is defined then the architecture specific code
-(or the device drivers - like HPET) may register time interpolators.
-These are typically defined in the following way:
-
-static struct time_interpolator my_interpolator {
-        .frequency = MY_FREQUENCY,
-        .source = TIME_SOURCE_MMIO32,
-        .shift = 8,             /* scaling for higher accuracy */
-        .drift = -1,            /* Unknown drift */
-        .jitter = 0             /* time source is stable */
-};
-
-void time_init(void)
-{
-        ....
-        /* Initialization of the timer *.
-        my_interpolator.address = &my_timer;
-        register_time_interpolator(&my_interpolator);
-        ....
-}
-
-For more details see include/linux/timex.h and kernel/timer.c.
-
-Christoph Lameter <christoph@lameter.com>, October 31, 2004
-
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 616c96e73483..36c7b9682aa6 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -62,7 +62,11 @@ config GENERIC_CALIBRATE_DELAY
         bool
         default y
 
-config TIME_INTERPOLATION
+config GENERIC_TIME
+        bool
+        default y
+
+config GENERIC_TIME_VSYSCALL
         bool
         default y
 
diff --git a/arch/ia64/configs/bigsur_defconfig b/arch/ia64/configs/bigsur_defconfig
index 90e9c2e61bf4..9eb48c0927b0 100644
--- a/arch/ia64/configs/bigsur_defconfig
+++ b/arch/ia64/configs/bigsur_defconfig
@@ -85,7 +85,7 @@ CONFIG_MMU=y
 CONFIG_SWIOTLB=y
 CONFIG_RWSEM_XCHGADD_ALGORITHM=y
 CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
 CONFIG_EFI=y
 CONFIG_GENERIC_IOMAP=y
 CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y
diff --git a/arch/ia64/configs/gensparse_defconfig b/arch/ia64/configs/gensparse_defconfig
index 0d29aa2066b3..3a9ed951db08 100644
--- a/arch/ia64/configs/gensparse_defconfig
+++ b/arch/ia64/configs/gensparse_defconfig
@@ -86,7 +86,7 @@ CONFIG_MMU=y
 CONFIG_SWIOTLB=y
 CONFIG_RWSEM_XCHGADD_ALGORITHM=y
 CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
 CONFIG_EFI=y
 CONFIG_GENERIC_IOMAP=y
 CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y
diff --git a/arch/ia64/configs/sim_defconfig b/arch/ia64/configs/sim_defconfig
index d9146c31ea13..c420d9f3df98 100644
--- a/arch/ia64/configs/sim_defconfig
+++ b/arch/ia64/configs/sim_defconfig
@@ -86,7 +86,7 @@ CONFIG_MMU=y
 CONFIG_SWIOTLB=y
 CONFIG_RWSEM_XCHGADD_ALGORITHM=y
 CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
 CONFIG_EFI=y
 CONFIG_GENERIC_IOMAP=y
 CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y
diff --git a/arch/ia64/configs/sn2_defconfig b/arch/ia64/configs/sn2_defconfig
index 64e951de4e57..4c9ffc47bc7a 100644
--- a/arch/ia64/configs/sn2_defconfig
+++ b/arch/ia64/configs/sn2_defconfig
@@ -93,7 +93,7 @@ CONFIG_SWIOTLB=y
 CONFIG_RWSEM_XCHGADD_ALGORITHM=y
 CONFIG_GENERIC_FIND_NEXT_BIT=y
 CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
 CONFIG_DMI=y
 CONFIG_EFI=y
 CONFIG_GENERIC_IOMAP=y
diff --git a/arch/ia64/configs/tiger_defconfig b/arch/ia64/configs/tiger_defconfig
index 205bbc30b0d0..3dbb3987df27 100644
--- a/arch/ia64/configs/tiger_defconfig
+++ b/arch/ia64/configs/tiger_defconfig
@@ -97,7 +97,7 @@ CONFIG_RWSEM_XCHGADD_ALGORITHM=y
 # CONFIG_ARCH_HAS_ILOG2_U64 is not set
 CONFIG_GENERIC_FIND_NEXT_BIT=y
 CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
 CONFIG_DMI=y
 CONFIG_EFI=y
 CONFIG_GENERIC_IOMAP=y
diff --git a/arch/ia64/configs/zx1_defconfig b/arch/ia64/configs/zx1_defconfig
index 1c7955c16358..4a060fc39934 100644
--- a/arch/ia64/configs/zx1_defconfig
+++ b/arch/ia64/configs/zx1_defconfig
@@ -96,7 +96,7 @@ CONFIG_RWSEM_XCHGADD_ALGORITHM=y
 # CONFIG_ARCH_HAS_ILOG2_U64 is not set
 CONFIG_GENERIC_FIND_NEXT_BIT=y
 CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
 CONFIG_DMI=y
 CONFIG_EFI=y
 CONFIG_GENERIC_IOMAP=y
diff --git a/arch/ia64/defconfig b/arch/ia64/defconfig
index 80298ef905eb..03172dc8c403 100644
--- a/arch/ia64/defconfig
+++ b/arch/ia64/defconfig
@@ -97,7 +97,7 @@ CONFIG_RWSEM_XCHGADD_ALGORITHM=y
 # CONFIG_ARCH_HAS_ILOG2_U64 is not set
 CONFIG_GENERIC_FIND_NEXT_BIT=y
 CONFIG_GENERIC_CALIBRATE_DELAY=y
-CONFIG_TIME_INTERPOLATION=y
+CONFIG_GENERIC_TIME=y
 CONFIG_DMI=y
 CONFIG_EFI=y
 CONFIG_GENERIC_IOMAP=y
diff --git a/arch/ia64/kernel/asm-offsets.c b/arch/ia64/kernel/asm-offsets.c
index 2236fabbb3c6..0aebc6f79e95 100644
--- a/arch/ia64/kernel/asm-offsets.c
+++ b/arch/ia64/kernel/asm-offsets.c
@@ -7,6 +7,7 @@
 #define ASM_OFFSETS_C 1
 
 #include <linux/sched.h>
+#include <linux/clocksource.h>
 
 #include <asm-ia64/processor.h>
 #include <asm-ia64/ptrace.h>
@@ -15,6 +16,7 @@
 #include <asm-ia64/mca.h>
 
 #include "../kernel/sigframe.h"
+#include "../kernel/fsyscall_gtod_data.h"
 
 #define DEFINE(sym, val) \
         asm volatile("\n->" #sym " %0 " #val : : "i" (val))
@@ -256,17 +258,24 @@ void foo(void)
         BLANK();
 
         /* used by fsys_gettimeofday in arch/ia64/kernel/fsys.S */
-        DEFINE(IA64_TIME_INTERPOLATOR_ADDRESS_OFFSET, offsetof (struct time_interpolator, addr));
-        DEFINE(IA64_TIME_INTERPOLATOR_SOURCE_OFFSET, offsetof (struct time_interpolator, source));
-        DEFINE(IA64_TIME_INTERPOLATOR_SHIFT_OFFSET, offsetof (struct time_interpolator, shift));
-        DEFINE(IA64_TIME_INTERPOLATOR_NSEC_OFFSET, offsetof (struct time_interpolator, nsec_per_cyc));
-        DEFINE(IA64_TIME_INTERPOLATOR_OFFSET_OFFSET, offsetof (struct time_interpolator, offset));
-        DEFINE(IA64_TIME_INTERPOLATOR_LAST_CYCLE_OFFSET, offsetof (struct time_interpolator, last_cycle));
-        DEFINE(IA64_TIME_INTERPOLATOR_LAST_COUNTER_OFFSET, offsetof (struct time_interpolator, last_counter));
-        DEFINE(IA64_TIME_INTERPOLATOR_JITTER_OFFSET, offsetof (struct time_interpolator, jitter));
-        DEFINE(IA64_TIME_INTERPOLATOR_MASK_OFFSET, offsetof (struct time_interpolator, mask));
-        DEFINE(IA64_TIME_SOURCE_CPU, TIME_SOURCE_CPU);
-        DEFINE(IA64_TIME_SOURCE_MMIO64, TIME_SOURCE_MMIO64);
-        DEFINE(IA64_TIME_SOURCE_MMIO32, TIME_SOURCE_MMIO32);
-        DEFINE(IA64_TIMESPEC_TV_NSEC_OFFSET, offsetof (struct timespec, tv_nsec));
+        DEFINE(IA64_GTOD_LOCK_OFFSET,
+                offsetof (struct fsyscall_gtod_data_t, lock));
+        DEFINE(IA64_GTOD_WALL_TIME_OFFSET,
+                offsetof (struct fsyscall_gtod_data_t, wall_time));
+        DEFINE(IA64_GTOD_MONO_TIME_OFFSET,
+                offsetof (struct fsyscall_gtod_data_t, monotonic_time));
+        DEFINE(IA64_CLKSRC_MASK_OFFSET,
+                offsetof (struct fsyscall_gtod_data_t, clk_mask));
+        DEFINE(IA64_CLKSRC_MULT_OFFSET,
+                offsetof (struct fsyscall_gtod_data_t, clk_mult));
+        DEFINE(IA64_CLKSRC_SHIFT_OFFSET,
+                offsetof (struct fsyscall_gtod_data_t, clk_shift));
+        DEFINE(IA64_CLKSRC_MMIO_OFFSET,
+                offsetof (struct fsyscall_gtod_data_t, clk_fsys_mmio));
+        DEFINE(IA64_CLKSRC_CYCLE_LAST_OFFSET,
+                offsetof (struct fsyscall_gtod_data_t, clk_cycle_last));
+        DEFINE(IA64_ITC_JITTER_OFFSET,
+                offsetof (struct itc_jitter_data_t, itc_jitter));
+        DEFINE(IA64_ITC_LASTCYCLE_OFFSET,
+                offsetof (struct itc_jitter_data_t, itc_lastcycle));
 }
diff --git a/arch/ia64/kernel/cyclone.c b/arch/ia64/kernel/cyclone.c
index e00b21514f7c..2fd96d9062a1 100644
--- a/arch/ia64/kernel/cyclone.c
+++ b/arch/ia64/kernel/cyclone.c
@@ -3,6 +3,7 @@
 #include <linux/time.h>
 #include <linux/errno.h>
 #include <linux/timex.h>
+#include <linux/clocksource.h>
 #include <asm/io.h>
 
 /* IBM Summit (EXA) Cyclone counter code*/
@@ -18,13 +19,21 @@ void __init cyclone_setup(void)
         use_cyclone = 1;
 }
 
+static void __iomem *cyclone_mc;
 
-struct time_interpolator cyclone_interpolator = {
-        .source =       TIME_SOURCE_MMIO64,
-        .shift =        16,
-        .frequency =    CYCLONE_TIMER_FREQ,
-        .drift =        -100,
-        .mask =         (1LL << 40) - 1
+static cycle_t read_cyclone(void)
+{
+        return (cycle_t)readq((void __iomem *)cyclone_mc);
+}
+
+static struct clocksource clocksource_cyclone = {
+        .name           = "cyclone",
+        .rating         = 300,
+        .read           = read_cyclone,
+        .mask           = (1LL << 40) - 1,
+        .mult           = 0, /*to be caluclated*/
+        .shift          = 16,
+        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 int __init init_cyclone_clock(void)
@@ -44,13 +53,15 @@ int __init init_cyclone_clock(void)
         offset = (CYCLONE_CBAR_ADDR);
         reg = (u64*)ioremap_nocache(offset, sizeof(u64));
         if(!reg){
-                printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
+                printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
+                                " register.\n");
                 use_cyclone = 0;
                 return -ENODEV;
         }
         base = readq(reg);
         if(!base){
-                printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
+                printk(KERN_ERR "Summit chipset: Could not find valid CBAR"
+                                " value.\n");
                 use_cyclone = 0;
                 return -ENODEV;
         }
@@ -60,7 +71,8 @@ int __init init_cyclone_clock(void)
         offset = (base + CYCLONE_PMCC_OFFSET);
         reg = (u64*)ioremap_nocache(offset, sizeof(u64));
         if(!reg){
-                printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
+                printk(KERN_ERR "Summit chipset: Could not find valid PMCC"
+                                " register.\n");
                 use_cyclone = 0;
                 return -ENODEV;
         }
@@ -71,7 +83,8 @@ int __init init_cyclone_clock(void)
         offset = (base + CYCLONE_MPCS_OFFSET);
         reg = (u64*)ioremap_nocache(offset, sizeof(u64));
         if(!reg){
-                printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
+                printk(KERN_ERR "Summit chipset: Could not find valid MPCS"
+                                " register.\n");
                 use_cyclone = 0;
                 return -ENODEV;
         }
@@ -82,7 +95,8 @@ int __init init_cyclone_clock(void)
         offset = (base + CYCLONE_MPMC_OFFSET);
         cyclone_timer = (u32*)ioremap_nocache(offset, sizeof(u32));
         if(!cyclone_timer){
-                printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
+                printk(KERN_ERR "Summit chipset: Could not find valid MPMC"
+                                " register.\n");
                 use_cyclone = 0;
                 return -ENODEV;
         }
@@ -93,7 +107,8 @@ int __init init_cyclone_clock(void)
                 int stall = 100;
                 while(stall--) barrier();
                 if(readl(cyclone_timer) == old){
-                        printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
+                        printk(KERN_ERR "Summit chipset: Counter not counting!"
+                                        " DISABLED\n");
                         iounmap(cyclone_timer);
                         cyclone_timer = 0;
                         use_cyclone = 0;
@@ -101,8 +116,11 @@ int __init init_cyclone_clock(void)
                 }
         }
         /* initialize last tick */
-        cyclone_interpolator.addr = cyclone_timer;
-        register_time_interpolator(&cyclone_interpolator);
+        cyclone_mc = cyclone_timer;
+        clocksource_cyclone.fsys_mmio = cyclone_timer;
+        clocksource_cyclone.mult = clocksource_hz2mult(CYCLONE_TIMER_FREQ,
+                                                clocksource_cyclone.shift);
+        clocksource_register(&clocksource_cyclone);
 
         return 0;
 }
diff --git a/arch/ia64/kernel/fsys.S b/arch/ia64/kernel/fsys.S
index 3f926c2dc708..44841971f077 100644
--- a/arch/ia64/kernel/fsys.S
+++ b/arch/ia64/kernel/fsys.S
@@ -147,12 +147,11 @@ ENTRY(fsys_set_tid_address)
         FSYS_RETURN
 END(fsys_set_tid_address)
 
-/*
- * Ensure that the time interpolator structure is compatible with the asm code
- */
-#if IA64_TIME_INTERPOLATOR_SOURCE_OFFSET !=0 || IA64_TIME_INTERPOLATOR_SHIFT_OFFSET != 2 \
-        || IA64_TIME_INTERPOLATOR_JITTER_OFFSET != 3 || IA64_TIME_INTERPOLATOR_NSEC_OFFSET != 4
-#error fsys_gettimeofday incompatible with changes to struct time_interpolator
+#if IA64_GTOD_LOCK_OFFSET !=0
+#error fsys_gettimeofday incompatible with changes to struct fsyscall_gtod_data_t
+#endif
+#if IA64_ITC_JITTER_OFFSET !=0
+#error fsys_gettimeofday incompatible with changes to struct itc_jitter_data_t
 #endif
 #define CLOCK_REALTIME 0
 #define CLOCK_MONOTONIC 1
@@ -179,126 +178,124 @@ ENTRY(fsys_gettimeofday)
         // r11 = preserved: saved ar.pfs
         // r12 = preserved: memory stack
         // r13 = preserved: thread pointer
-        // r14 = address of mask / mask
+        // r14 = address of mask / mask value
         // r15 = preserved: system call number
         // r16 = preserved: current task pointer
-        // r17 = wall to monotonic use
-        // r18 = time_interpolator->offset
-        // r19 = address of wall_to_monotonic
-        // r20 = pointer to struct time_interpolator / pointer to time_interpolator->address
-        // r21 = shift factor
-        // r22 = address of time interpolator->last_counter
-        // r23 = address of time_interpolator->last_cycle
-        // r24 = adress of time_interpolator->offset
-        // r25 = last_cycle value
-        // r26 = last_counter value
-        // r27 = pointer to xtime
+        // r17 = (not used)
+        // r18 = (not used)
+        // r19 = address of itc_lastcycle
+        // r20 = struct fsyscall_gtod_data (= address of gtod_lock.sequence)
+        // r21 = address of mmio_ptr
+        // r22 = address of wall_time or monotonic_time
+        // r23 = address of shift / value
+        // r24 = address mult factor / cycle_last value
+        // r25 = itc_lastcycle value
+        // r26 = address clocksource cycle_last
+        // r27 = (not used)
         // r28 = sequence number at the beginning of critcal section
-        // r29 = address of seqlock
+        // r29 = address of itc_jitter
         // r30 = time processing flags / memory address
         // r31 = pointer to result
         // Predicates
         // p6,p7 short term use
         // p8 = timesource ar.itc
         // p9 = timesource mmio64
-        // p10 = timesource mmio32
+        // p10 = timesource mmio32 - not used
         // p11 = timesource not to be handled by asm code
-        // p12 = memory time source ( = p9 | p10)
-        // p13 = do cmpxchg with time_interpolator_last_cycle
+        // p12 = memory time source ( = p9 | p10) - not used
+        // p13 = do cmpxchg with itc_lastcycle
         // p14 = Divide by 1000
         // p15 = Add monotonic
         //
-        // Note that instructions are optimized for McKinley. McKinley can process two
-        // bundles simultaneously and therefore we continuously try to feed the CPU
-        // two bundles and then a stop.
-        tnat.nz p6,p0 = r31     // branch deferred since it does not fit into bundle structure
+        // Note that instructions are optimized for McKinley. McKinley can
+        // process two bundles simultaneously and therefore we continuously
+        // try to feed the CPU two bundles and then a stop.
+        //
+        // Additional note that code has changed a lot. Optimization is TBD.
+        // Comments begin with "?" are maybe outdated.
+        tnat.nz p6,p0 = r31     // ? branch deferred to fit later bundle
         mov pr = r30,0xc000     // Set predicates according to function
         add r2 = TI_FLAGS+IA64_TASK_SIZE,r16
-        movl r20 = time_interpolator
+        movl r20 = fsyscall_gtod_data // load fsyscall gettimeofday data address
         ;;
-        ld8 r20 = [r20]         // get pointer to time_interpolator structure
-        movl r29 = xtime_lock
+        movl r29 = itc_jitter_data      // itc_jitter
+        add r22 = IA64_GTOD_WALL_TIME_OFFSET,r20        // wall_time
         ld4 r2 = [r2]           // process work pending flags
-        movl r27 = xtime
-        ;;      // only one bundle here
-        ld8 r21 = [r20]         // first quad with control information
+        ;;
+(p15)   add r22 = IA64_GTOD_MONO_TIME_OFFSET,r20        // monotonic_time
+        add r21 = IA64_CLKSRC_MMIO_OFFSET,r20
+        add r19 = IA64_ITC_LASTCYCLE_OFFSET,r29
         and r2 = TIF_ALLWORK_MASK,r2
-(p6)    br.cond.spnt.few .fail_einval   // deferred branch
+(p6)    br.cond.spnt.few .fail_einval   // ? deferred branch
         ;;
-        add r10 = IA64_TIME_INTERPOLATOR_ADDRESS_OFFSET,r20
-        extr r3 = r21,32,32     // time_interpolator->nsec_per_cyc
-        extr r8 = r21,0,16      // time_interpolator->source
+        add r26 = IA64_CLKSRC_CYCLE_LAST_OFFSET,r20 // clksrc_cycle_last
         cmp.ne p6, p0 = 0, r2   // Fallback if work is scheduled
 (p6)    br.cond.spnt.many fsys_fallback_syscall
         ;;
-        cmp.eq p8,p12 = 0,r8    // Check for cpu timer
-        cmp.eq p9,p0 = 1,r8     // MMIO64 ?
-        extr r2 = r21,24,8      // time_interpolator->jitter
-        cmp.eq p10,p0 = 2,r8    // MMIO32 ?
-        cmp.ltu p11,p0 = 2,r8   // function or other clock
-(p11)   br.cond.spnt.many fsys_fallback_syscall
+        // Begin critical section
+.time_redo:
+        ld4.acq r28 = [r20]     // gtod_lock.sequence, Must take first
+        ;;
+        and r28 = ~1,r28        // And make sequence even to force retry if odd
         ;;
-        setf.sig f7 = r3        // Setup for scaling of counter
-(p15)   movl r19 = wall_to_monotonic
-(p12)   ld8 r30 = [r10]
-        cmp.ne p13,p0 = r2,r0   // need jitter compensation?
-        extr r21 = r21,16,8     // shift factor
+        ld8 r30 = [r21]         // clocksource->mmio_ptr
+        add r24 = IA64_CLKSRC_MULT_OFFSET,r20
+        ld4 r2 = [r29]          // itc_jitter value
+        add r23 = IA64_CLKSRC_SHIFT_OFFSET,r20
+        add r14 = IA64_CLKSRC_MASK_OFFSET,r20
         ;;
-.time_redo:
-        .pred.rel.mutex p8,p9,p10
-        ld4.acq r28 = [r29]     // xtime_lock.sequence. Must come first for locking purposes
+        ld4 r3 = [r24]          // clocksource mult value
+        ld8 r14 = [r14]         // clocksource mask value
+        cmp.eq p8,p9 = 0,r30    // use cpu timer if no mmio_ptr
         ;;
-        and r28 = ~1,r28        // Make sequence even to force retry if odd
+        setf.sig f7 = r3        // Setup for mult scaling of counter
+(p8)    cmp.ne p13,p0 = r2,r0   // need itc_jitter compensation, set p13
+        ld4 r23 = [r23]         // clocksource shift value
+        ld8 r24 = [r26]         // get clksrc_cycle_last value
+(p9)    cmp.eq p13,p0 = 0,r30   // if mmio_ptr, clear p13 jitter control
         ;;
+        .pred.rel.mutex p8,p9
 (p8)    mov r2 = ar.itc         // CPU_TIMER. 36 clocks latency!!!
-        add r22 = IA64_TIME_INTERPOLATOR_LAST_COUNTER_OFFSET,r20
-(p9)    ld8 r2 = [r30]          // readq(ti->address). Could also have latency issues..
-(p10)   ld4 r2 = [r30]          // readw(ti->address)
-(p13)   add r23 = IA64_TIME_INTERPOLATOR_LAST_CYCLE_OFFSET,r20
-        ;;                      // could be removed by moving the last add upward
-        ld8 r26 = [r22]         // time_interpolator->last_counter
-(p13)   ld8 r25 = [r23]         // time interpolator->last_cycle
-        add r24 = IA64_TIME_INTERPOLATOR_OFFSET_OFFSET,r20
-(p15)   ld8 r17 = [r19],IA64_TIMESPEC_TV_NSEC_OFFSET
-        ld8 r9 = [r27],IA64_TIMESPEC_TV_NSEC_OFFSET
-        add r14 = IA64_TIME_INTERPOLATOR_MASK_OFFSET, r20
-        ;;
-        ld8 r18 = [r24]         // time_interpolator->offset
-        ld8 r8 = [r27],-IA64_TIMESPEC_TV_NSEC_OFFSET    // xtime.tv_nsec
-(p13)   sub r3 = r25,r2 // Diff needed before comparison (thanks davidm)
-        ;;
-        ld8 r14 = [r14]         // time_interpolator->mask
-(p13)   cmp.gt.unc p6,p7 = r3,r0        // check if it is less than last. p6,p7 cleared
-        sub r10 = r2,r26        // current_counter - last_counter
-        ;;
-(p6)    sub r10 = r25,r26       // time we got was less than last_cycle
+(p9)    ld8 r2 = [r30]          // MMIO_TIMER. Could also have latency issues..
+(p13)   ld8 r25 = [r19]         // get itc_lastcycle value
+        ;;              // ? could be removed by moving the last add upward
+        ld8 r9 = [r22],IA64_TIMESPEC_TV_NSEC_OFFSET     // tv_sec
+        ;;
+        ld8 r8 = [r22],-IA64_TIMESPEC_TV_NSEC_OFFSET    // tv_nsec
+(p13)   sub r3 = r25,r2         // Diff needed before comparison (thanks davidm)
+        ;;
+(p13)   cmp.gt.unc p6,p7 = r3,r0 // check if it is less than last. p6,p7 cleared
+        sub r10 = r2,r24        // current_cycle - last_cycle
+        ;;
+(p6)    sub r10 = r25,r24       // time we got was less than last_cycle
 (p7)    mov ar.ccv = r25        // more than last_cycle. Prep for cmpxchg
         ;;
+(p7)    cmpxchg8.rel r3 = [r19],r2,ar.ccv
+        ;;
+(p7)    cmp.ne p7,p0 = r25,r3   // if cmpxchg not successful
+        ;;
+(p7)    sub r10 = r3,r24        // then use new last_cycle instead
+        ;;
         and r10 = r10,r14       // Apply mask
         ;;
         setf.sig f8 = r10
         nop.i 123
         ;;
-(p7)    cmpxchg8.rel r3 = [r23],r2,ar.ccv
-EX(.fail_efault, probe.w.fault r31, 3)  // This takes 5 cycles and we have spare time
+        // fault check takes 5 cycles and we have spare time
+EX(.fail_efault, probe.w.fault r31, 3)
         xmpy.l f8 = f8,f7       // nsec_per_cyc*(counter-last_counter)
-(p15)   add r9 = r9,r17         // Add wall to monotonic.secs to result secs
         ;;
-(p15)   ld8 r17 = [r19],-IA64_TIMESPEC_TV_NSEC_OFFSET
-(p7)    cmp.ne p7,p0 = r25,r3   // if cmpxchg not successful redo
-        // simulate tbit.nz.or p7,p0 = r28,0
+        // ? simulate tbit.nz.or p7,p0 = r28,0
         getf.sig r2 = f8
         mf
-        add r8 = r8,r18         // Add time interpolator offset
         ;;
-        ld4 r10 = [r29]         // xtime_lock.sequence
-(p15)   add r8 = r8, r17        // Add monotonic.nsecs to nsecs
-        shr.u r2 = r2,r21
-        ;;              // overloaded 3 bundles!
-        // End critical section.
+        ld4 r10 = [r20]         // gtod_lock.sequence
+        shr.u r2 = r2,r23       // shift by factor
+        ;;              // ? overloaded 3 bundles!
         add r8 = r8,r2          // Add xtime.nsecs
-        cmp4.ne.or p7,p0 = r28,r10
-(p7)    br.cond.dpnt.few .time_redo     // sequence number changed ?
+        cmp4.ne p7,p0 = r28,r10
+(p7)    br.cond.dpnt.few .time_redo     // sequence number changed, redo
+        // End critical section.
         // Now r8=tv->tv_nsec and r9=tv->tv_sec
         mov r10 = r0
         movl r2 = 1000000000
@@ -308,19 +305,19 @@ EX(.fail_efault, probe.w.fault r31, 3)	// This takes 5 cycles and we have spare
 .time_normalize:
         mov r21 = r8
         cmp.ge p6,p0 = r8,r2
-(p14)   shr.u r20 = r8, 3               // We can repeat this if necessary just wasting some time
+(p14)   shr.u r20 = r8, 3 // We can repeat this if necessary just wasting time
         ;;
 (p14)   setf.sig f8 = r20
 (p6)    sub r8 = r8,r2
-(p6)    add r9 = 1,r9                   // two nops before the branch.
-(p14)   setf.sig f7 = r3                // Chances for repeats are 1 in 10000 for gettod
+(p6)    add r9 = 1,r9           // two nops before the branch.
+(p14)   setf.sig f7 = r3        // Chances for repeats are 1 in 10000 for gettod
 (p6)    br.cond.dpnt.few .time_normalize
         ;;
         // Divided by 8 though shift. Now divide by 125
         // The compiler was able to do that with a multiply
         // and a shift and we do the same
-EX(.fail_efault, probe.w.fault r23, 3)          // This also costs 5 cycles
-(p14)   xmpy.hu f8 = f8, f7                     // xmpy has 5 cycles latency so use it...
+EX(.fail_efault, probe.w.fault r23, 3)  // This also costs 5 cycles
+(p14)   xmpy.hu f8 = f8, f7             // xmpy has 5 cycles latency so use it
         ;;
         mov r8 = r0
 (p14)   getf.sig r2 = f8
diff --git a/arch/ia64/kernel/fsyscall_gtod_data.h b/arch/ia64/kernel/fsyscall_gtod_data.h
new file mode 100644
index 000000000000..490dab55fba3
--- /dev/null
+++ b/arch/ia64/kernel/fsyscall_gtod_data.h
@@ -0,0 +1,23 @@
+/*
+ * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
+ *        Contributed by Peter Keilty <peter.keilty@hp.com>
+ *
+ * fsyscall gettimeofday data
+ */
+
+struct fsyscall_gtod_data_t {
+        seqlock_t       lock;
+        struct timespec wall_time;
+        struct timespec monotonic_time;
+        cycle_t         clk_mask;
+        u32             clk_mult;
+        u32             clk_shift;
+        void            *clk_fsys_mmio;
+        cycle_t         clk_cycle_last;
+} __attribute__ ((aligned (L1_CACHE_BYTES)));
+
+struct itc_jitter_data_t {
+        int             itc_jitter;
+        cycle_t         itc_lastcycle;
+} __attribute__ ((aligned (L1_CACHE_BYTES)));
+
diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index 3486fe7d6e65..627785c48ea9 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -19,6 +19,7 @@
 #include <linux/interrupt.h>
 #include <linux/efi.h>
 #include <linux/timex.h>
+#include <linux/clocksource.h>
 
 #include <asm/machvec.h>
 #include <asm/delay.h>
@@ -28,6 +29,16 @@
 #include <asm/sections.h>
 #include <asm/system.h>
 
+#include "fsyscall_gtod_data.h"
+
+static cycle_t itc_get_cycles(void);
+
+struct fsyscall_gtod_data_t fsyscall_gtod_data = {
+        .lock = SEQLOCK_UNLOCKED,
+};
+
+struct itc_jitter_data_t itc_jitter_data;
+
 volatile int time_keeper_id = 0; /* smp_processor_id() of time-keeper */
 
 #ifdef CONFIG_IA64_DEBUG_IRQ
@@ -37,11 +48,16 @@ EXPORT_SYMBOL(last_cli_ip);
 
 #endif
 
-static struct time_interpolator itc_interpolator = {
-        .shift = 16,
-        .mask = 0xffffffffffffffffLL,
-        .source = TIME_SOURCE_CPU
+static struct clocksource clocksource_itc = {
+        .name           = "itc",
+        .rating         = 350,
+        .read           = itc_get_cycles,
+        .mask           = 0xffffffffffffffff,
+        .mult           = 0, /*to be caluclated*/
+        .shift          = 16,
+        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };
+static struct clocksource *itc_clocksource;
 
 static irqreturn_t
 timer_interrupt (int irq, void *dev_id)
@@ -210,8 +226,6 @@ ia64_init_itm (void)
                                         + itc_freq/2)/itc_freq;
 
         if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT)) {
-                itc_interpolator.frequency = local_cpu_data->itc_freq;
-                itc_interpolator.drift = itc_drift;
 #ifdef CONFIG_SMP
                 /* On IA64 in an SMP configuration ITCs are never accurately synchronized.
                  * Jitter compensation requires a cmpxchg which may limit
@@ -223,15 +237,50 @@ ia64_init_itm (void)
                  * even going backward) if the ITC offsets between the individual CPUs
                  * are too large.
                  */
-                if (!nojitter) itc_interpolator.jitter = 1;
+                if (!nojitter)
+                        itc_jitter_data.itc_jitter = 1;
 #endif
-                register_time_interpolator(&itc_interpolator);
         }
 
         /* Setup the CPU local timer tick */
         ia64_cpu_local_tick();
+
+        if (!itc_clocksource) {
+                /* Sort out mult/shift values: */
+                clocksource_itc.mult =
+                        clocksource_hz2mult(local_cpu_data->itc_freq,
+                                                clocksource_itc.shift);
+                clocksource_register(&clocksource_itc);
+                itc_clocksource = &clocksource_itc;
+        }
 }
 
+static cycle_t itc_get_cycles()
+{
+        u64 lcycle, now, ret;
+
+        if (!itc_jitter_data.itc_jitter)
+                return get_cycles();
+
+        lcycle = itc_jitter_data.itc_lastcycle;
+        now = get_cycles();
+        if (lcycle && time_after(lcycle, now))
+                return lcycle;
+
+        /*
+         * Keep track of the last timer value returned.
+         * In an SMP environment, you could lose out in contention of
+         * cmpxchg. If so, your cmpxchg returns new value which the
+         * winner of contention updated to. Use the new value instead.
+         */
+        ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, now);
+        if (unlikely(ret != lcycle))
+                return ret;
+
+        return now;
+}
+
+
 static struct irqaction timer_irqaction = {
         .handler =      timer_interrupt,
         .flags =        IRQF_DISABLED | IRQF_IRQPOLL,
@@ -307,3 +356,34 @@ ia64_setup_printk_clock(void)
         if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT))
                 ia64_printk_clock = ia64_itc_printk_clock;
 }
+
+void update_vsyscall(struct timespec *wall, struct clocksource *c)
+{
+        unsigned long flags;
+
+        write_seqlock_irqsave(&fsyscall_gtod_data.lock, flags);
+
+        /* copy fsyscall clock data */
+        fsyscall_gtod_data.clk_mask = c->mask;
+        fsyscall_gtod_data.clk_mult = c->mult;
+        fsyscall_gtod_data.clk_shift = c->shift;
+        fsyscall_gtod_data.clk_fsys_mmio = c->fsys_mmio;
+        fsyscall_gtod_data.clk_cycle_last = c->cycle_last;
+
+        /* 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
+                                                        + wall->tv_sec;
+        fsyscall_gtod_data.monotonic_time.tv_nsec = wall_to_monotonic.tv_nsec
+                                                        + wall->tv_nsec;
+
+        /* normalize */
+        while (fsyscall_gtod_data.monotonic_time.tv_nsec >= NSEC_PER_SEC) {
+                fsyscall_gtod_data.monotonic_time.tv_nsec -= NSEC_PER_SEC;
+                fsyscall_gtod_data.monotonic_time.tv_sec++;
+        }
+
+        write_sequnlock_irqrestore(&fsyscall_gtod_data.lock, flags);
+}
+
diff --git a/arch/ia64/sn/kernel/sn2/timer.c b/arch/ia64/sn/kernel/sn2/timer.c
index 56a88b6df4b4..19e25d2b64fc 100644
--- a/arch/ia64/sn/kernel/sn2/timer.c
+++ b/arch/ia64/sn/kernel/sn2/timer.c
@@ -11,6 +11,7 @@
 #include <linux/sched.h>
 #include <linux/time.h>
 #include <linux/interrupt.h>
+#include <linux/clocksource.h>
 
 #include <asm/hw_irq.h>
 #include <asm/system.h>
@@ -22,11 +23,21 @@
 
 extern unsigned long sn_rtc_cycles_per_second;
 
-static struct time_interpolator sn2_interpolator = {
-        .drift = -1,
-        .shift = 10,
-        .mask = (1LL << 55) - 1,
-        .source = TIME_SOURCE_MMIO64
+static void __iomem *sn2_mc;
+
+static cycle_t read_sn2(void)
+{
+        return (cycle_t)readq(sn2_mc);
+}
+
+static struct clocksource clocksource_sn2 = {
+        .name           = "sn2_rtc",
+        .rating         = 300,
+        .read           = read_sn2,
+        .mask           = (1LL << 55) - 1,
+        .mult           = 0,
+        .shift          = 10,
+        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
 /*
@@ -47,9 +58,11 @@ ia64_sn_udelay (unsigned long usecs)
 
 void __init sn_timer_init(void)
 {
-        sn2_interpolator.frequency = sn_rtc_cycles_per_second;
-        sn2_interpolator.addr = RTC_COUNTER_ADDR;
-        register_time_interpolator(&sn2_interpolator);
+        sn2_mc = RTC_COUNTER_ADDR;
+        clocksource_sn2.fsys_mmio = RTC_COUNTER_ADDR;
+        clocksource_sn2.mult = clocksource_hz2mult(sn_rtc_cycles_per_second,
+                                                        clocksource_sn2.shift);
+        clocksource_register(&clocksource_sn2);
 
         ia64_udelay = &ia64_sn_udelay;
 }
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 80ffc7829916..bb5d23be4260 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -475,7 +475,7 @@ static void acpi_processor_idle(void)
                 /* Get end time (ticks) */
                 t2 = inl(acpi_gbl_FADT.xpm_timer_block.address);
 
-#ifdef CONFIG_GENERIC_TIME
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
                 /* TSC halts in C2, so notify users */
                 mark_tsc_unstable("possible TSC halt in C2");
 #endif
@@ -517,7 +517,7 @@ static void acpi_processor_idle(void)
                         acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0);
                 }
 
-#ifdef CONFIG_GENERIC_TIME
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
                 /* TSC halts in C3, so notify users */
                 mark_tsc_unstable("TSC halts in C3");
 #endif
diff --git a/drivers/char/hpet.c b/drivers/char/hpet.c
index 0be700f4e8fd..ba0e74ad74bb 100644
--- a/drivers/char/hpet.c
+++ b/drivers/char/hpet.c
@@ -29,6 +29,7 @@
 #include <linux/bcd.h>
 #include <linux/seq_file.h>
 #include <linux/bitops.h>
+#include <linux/clocksource.h>
 
 #include <asm/current.h>
 #include <asm/uaccess.h>
@@ -51,8 +52,34 @@
 
 #define HPET_RANGE_SIZE         1024    /* from HPET spec */
 
+#if BITS_PER_LONG == 64
+#define write_counter(V, MC)    writeq(V, MC)
+#define read_counter(MC)        readq(MC)
+#else
+#define write_counter(V, MC)    writel(V, MC)
+#define read_counter(MC)        readl(MC)
+#endif
+
 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
 
+static void __iomem *hpet_mctr;
+
+static cycle_t read_hpet(void)
+{
+        return (cycle_t)read_counter((void __iomem *)hpet_mctr);
+}
+
+static struct clocksource clocksource_hpet = {
+        .name           = "hpet",
+        .rating         = 250,
+        .read           = read_hpet,
+        .mask           = 0xffffffffffffffff,
+        .mult           = 0, /*to be caluclated*/
+        .shift          = 10,
+        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
+};
+static struct clocksource *hpet_clocksource;
+
 /* A lock for concurrent access by app and isr hpet activity. */
 static DEFINE_SPINLOCK(hpet_lock);
 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
@@ -79,7 +106,7 @@ struct hpets {
         struct hpets *hp_next;
         struct hpet __iomem *hp_hpet;
         unsigned long hp_hpet_phys;
-        struct time_interpolator *hp_interpolator;
+        struct clocksource *hp_clocksource;
         unsigned long long hp_tick_freq;
         unsigned long hp_delta;
         unsigned int hp_ntimer;
@@ -94,13 +121,6 @@ static struct hpets *hpets;
 #define HPET_PERIODIC           0x0004
 #define HPET_SHARED_IRQ         0x0008
 
-#if BITS_PER_LONG == 64
-#define write_counter(V, MC)    writeq(V, MC)
-#define read_counter(MC)        readq(MC)
-#else
-#define write_counter(V, MC)    writel(V, MC)
-#define read_counter(MC)        readl(MC)
-#endif
 
 #ifndef readq
 static inline unsigned long long readq(void __iomem *addr)
@@ -737,27 +757,6 @@ static ctl_table dev_root[] = {
 
 static struct ctl_table_header *sysctl_header;
 
-static void hpet_register_interpolator(struct hpets *hpetp)
-{
-#ifdef  CONFIG_TIME_INTERPOLATION
-        struct time_interpolator *ti;
-
-        ti = kzalloc(sizeof(*ti), GFP_KERNEL);
-        if (!ti)
-                return;
-
-        ti->source = TIME_SOURCE_MMIO64;
-        ti->shift = 10;
-        ti->addr = &hpetp->hp_hpet->hpet_mc;
-        ti->frequency = hpetp->hp_tick_freq;
-        ti->drift = HPET_DRIFT;
-        ti->mask = -1;
-
-        hpetp->hp_interpolator = ti;
-        register_time_interpolator(ti);
-#endif
-}
-
 /*
  * Adjustment for when arming the timer with
  * initial conditions.  That is, main counter
@@ -909,7 +908,16 @@ int hpet_alloc(struct hpet_data *hdp)
         }
 
         hpetp->hp_delta = hpet_calibrate(hpetp);
-        hpet_register_interpolator(hpetp);
+
+        if (!hpet_clocksource) {
+                hpet_mctr = (void __iomem *)&hpetp->hp_hpet->hpet_mc;
+                CLKSRC_FSYS_MMIO_SET(clocksource_hpet.fsys_mmio, hpet_mctr);
+                clocksource_hpet.mult = clocksource_hz2mult(hpetp->hp_tick_freq,
+                                                clocksource_hpet.shift);
+                clocksource_register(&clocksource_hpet);
+                hpetp->hp_clocksource = &clocksource_hpet;
+                hpet_clocksource = &clocksource_hpet;
+        }
 
         return 0;
 }
@@ -995,7 +1003,7 @@ static int hpet_acpi_add(struct acpi_device *device)
 
 static int hpet_acpi_remove(struct acpi_device *device, int type)
 {
-        /* XXX need to unregister interpolator, dealloc mem, etc */
+        /* XXX need to unregister clocksource, dealloc mem, etc */
         return -EINVAL;
 }
 
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index bf297b03a4e4..16ea3374dddf 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -67,6 +67,12 @@ struct clocksource {
         unsigned long flags;
         cycle_t (*vread)(void);
         void (*resume)(void);
+#ifdef CONFIG_IA64
+        void *fsys_mmio;        /* used by fsyscall asm code */
+#define CLKSRC_FSYS_MMIO_SET(mmio, addr)      ((mmio) = (addr))
+#else
+#define CLKSRC_FSYS_MMIO_SET(mmio, addr)      do { } while (0)
+#endif
 
         /* timekeeping specific data, ignore */
         cycle_t cycle_interval;
diff --git a/include/linux/timex.h b/include/linux/timex.h
index da929dbbea2a..37ac3ff90faf 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -224,66 +224,6 @@ static inline int ntp_synced(void)
         __x < 0 ? -(-__x >> __s) : __x >> __s;  \
 })
 
-
-#ifdef CONFIG_TIME_INTERPOLATION
-
-#define TIME_SOURCE_CPU 0
-#define TIME_SOURCE_MMIO64 1
-#define TIME_SOURCE_MMIO32 2
-#define TIME_SOURCE_FUNCTION 3
-
-/* For proper operations time_interpolator clocks must run slightly slower
- * than the standard clock since the interpolator may only correct by having
- * time jump forward during a tick. A slower clock is usually a side effect
- * of the integer divide of the nanoseconds in a second by the frequency.
- * The accuracy of the division can be increased by specifying a shift.
- * However, this may cause the clock not to be slow enough.
- * The interpolator will self-tune the clock by slowing down if no
- * resets occur or speeding up if the time jumps per analysis cycle
- * become too high.
- *
- * Setting jitter compensates for a fluctuating timesource by comparing
- * to the last value read from the timesource to insure that an earlier value
- * is not returned by a later call. The price to pay
- * for the compensation is that the timer routines are not as scalable anymore.
- */
-
-struct time_interpolator {
-        u16 source;                     /* time source flags */
-        u8 shift;                       /* increases accuracy of multiply by shifting. */
-                                /* Note that bits may be lost if shift is set too high */
-        u8 jitter;                      /* if set compensate for fluctuations */
-        u32 nsec_per_cyc;               /* set by register_time_interpolator() */
-        void *addr;                     /* address of counter or function */
-        cycles_t mask;                  /* mask the valid bits of the counter */
-        unsigned long offset;           /* nsec offset at last update of interpolator */
-        u64 last_counter;               /* counter value in units of the counter at last update */
-        cycles_t last_cycle;            /* Last timer value if TIME_SOURCE_JITTER is set */
-        u64 frequency;                  /* frequency in counts/second */
-        long drift;                     /* drift in parts-per-million (or -1) */
-        unsigned long skips;            /* skips forward */
-        unsigned long ns_skipped;       /* nanoseconds skipped */
-        struct time_interpolator *next;
-};
-
-extern void register_time_interpolator(struct time_interpolator *);
-extern void unregister_time_interpolator(struct time_interpolator *);
-extern void time_interpolator_reset(void);
-extern unsigned long time_interpolator_get_offset(void);
-extern void time_interpolator_update(long delta_nsec);
-
-#else /* !CONFIG_TIME_INTERPOLATION */
-
-static inline void time_interpolator_reset(void)
-{
-}
-
-static inline void time_interpolator_update(long delta_nsec)
-{
-}
-
-#endif /* !CONFIG_TIME_INTERPOLATION */
-
 #define TICK_LENGTH_SHIFT       32
 
 #ifdef CONFIG_NO_HZ
diff --git a/kernel/time.c b/kernel/time.c
index ffe19149d770..e325597f5bf5 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -136,7 +136,6 @@ static inline void warp_clock(void)
         write_seqlock_irq(&xtime_lock);
         wall_to_monotonic.tv_sec -= sys_tz.tz_minuteswest * 60;
         xtime.tv_sec += sys_tz.tz_minuteswest * 60;
-        time_interpolator_reset();
         write_sequnlock_irq(&xtime_lock);
         clock_was_set();
 }
@@ -309,92 +308,6 @@ struct timespec timespec_trunc(struct timespec t, unsigned gran)
 }
 EXPORT_SYMBOL(timespec_trunc);
 
-#ifdef CONFIG_TIME_INTERPOLATION
-void getnstimeofday (struct timespec *tv)
-{
-        unsigned long seq,sec,nsec;
-
-        do {
-                seq = read_seqbegin(&xtime_lock);
-                sec = xtime.tv_sec;
-                nsec = xtime.tv_nsec+time_interpolator_get_offset();
-        } while (unlikely(read_seqretry(&xtime_lock, seq)));
-
-        while (unlikely(nsec >= NSEC_PER_SEC)) {
-                nsec -= NSEC_PER_SEC;
-                ++sec;
-        }
-        tv->tv_sec = sec;
-        tv->tv_nsec = nsec;
-}
-EXPORT_SYMBOL_GPL(getnstimeofday);
-
-int do_settimeofday (struct timespec *tv)
-{
-        time_t wtm_sec, sec = tv->tv_sec;
-        long wtm_nsec, nsec = tv->tv_nsec;
-
-        if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
-                return -EINVAL;
-
-        write_seqlock_irq(&xtime_lock);
-        {
-                wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
-                wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
-
-                set_normalized_timespec(&xtime, sec, nsec);
-                set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-
-                time_adjust = 0;                /* stop active adjtime() */
-                time_status |= STA_UNSYNC;
-                time_maxerror = NTP_PHASE_LIMIT;
-                time_esterror = NTP_PHASE_LIMIT;
-                time_interpolator_reset();
-        }
-        write_sequnlock_irq(&xtime_lock);
-        clock_was_set();
-        return 0;
-}
-EXPORT_SYMBOL(do_settimeofday);
-
-void do_gettimeofday (struct timeval *tv)
-{
-        unsigned long seq, nsec, usec, sec, offset;
-        do {
-                seq = read_seqbegin(&xtime_lock);
-                offset = time_interpolator_get_offset();
-                sec = xtime.tv_sec;
-                nsec = xtime.tv_nsec;
-        } while (unlikely(read_seqretry(&xtime_lock, seq)));
-
-        usec = (nsec + offset) / 1000;
-
-        while (unlikely(usec >= USEC_PER_SEC)) {
-                usec -= USEC_PER_SEC;
-                ++sec;
-        }
-
-        tv->tv_sec = sec;
-        tv->tv_usec = usec;
-
-        /*
-         * Make sure xtime.tv_sec [returned by sys_time()] always
-         * follows the gettimeofday() result precisely. This
-         * condition is extremely unlikely, it can hit at most
-         * once per second:
-         */
-        if (unlikely(xtime.tv_sec != tv->tv_sec)) {
-                unsigned long flags;
-
-                write_seqlock_irqsave(&xtime_lock, flags);
-                update_wall_time();
-                write_sequnlock_irqrestore(&xtime_lock, flags);
-        }
-}
-EXPORT_SYMBOL(do_gettimeofday);
-
-#else   /* CONFIG_TIME_INTERPOLATION */
-
 #ifndef CONFIG_GENERIC_TIME
 /*
  * Simulate gettimeofday using do_gettimeofday which only allows a timeval
@@ -410,7 +323,6 @@ void getnstimeofday(struct timespec *tv)
 }
 EXPORT_SYMBOL_GPL(getnstimeofday);
 #endif
-#endif  /* CONFIG_TIME_INTERPOLATION */
 
 /* 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
diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c
index 438c6b723ee2..b5e352597cbb 100644
--- a/kernel/time/ntp.c
+++ b/kernel/time/ntp.c
@@ -116,11 +116,6 @@ void second_overflow(void)
                 if (xtime.tv_sec % 86400 == 0) {
                         xtime.tv_sec--;
                         wall_to_monotonic.tv_sec++;
-                        /*
-                         * The timer interpolator will make time change
-                         * gradually instead of an immediate jump by one second
-                         */
-                        time_interpolator_update(-NSEC_PER_SEC);
                         time_state = TIME_OOP;
                         printk(KERN_NOTICE "Clock: inserting leap second "
                                         "23:59:60 UTC\n");
@@ -130,11 +125,6 @@ void second_overflow(void)
                 if ((xtime.tv_sec + 1) % 86400 == 0) {
                         xtime.tv_sec++;
                         wall_to_monotonic.tv_sec--;
-                        /*
-                         * Use of time interpolator for a gradual change of
-                         * time
-                         */
-                        time_interpolator_update(NSEC_PER_SEC);
                         time_state = TIME_WAIT;
                         printk(KERN_NOTICE "Clock: deleting leap second "
                                         "23:59:59 UTC\n");
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 89698776613e..88c81026e003 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -466,10 +466,6 @@ void update_wall_time(void)
                         second_overflow();
                 }
 
-                /* interpolator bits */
-                time_interpolator_update(clock->xtime_interval
-                                                >> clock->shift);
-
                 /* accumulate error between NTP and clock interval */
                 clock->error += current_tick_length();
                 clock->error -= clock->xtime_interval << (TICK_LENGTH_SHIFT - clock->shift);
diff --git a/kernel/timer.c b/kernel/timer.c
index d1e8b975c7ae..6ce1952eea7d 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1349,194 +1349,6 @@ void __init init_timers(void)
         open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
 }
 
-#ifdef CONFIG_TIME_INTERPOLATION
-
-struct time_interpolator *time_interpolator __read_mostly;
-static struct time_interpolator *time_interpolator_list __read_mostly;
-static DEFINE_SPINLOCK(time_interpolator_lock);
-
-static inline cycles_t time_interpolator_get_cycles(unsigned int src)
-{
-        unsigned long (*x)(void);
-
-        switch (src)
-        {
-                case TIME_SOURCE_FUNCTION:
-                        x = time_interpolator->addr;
-                        return x();
-
-                case TIME_SOURCE_MMIO64 :
-                        return readq_relaxed((void __iomem *)time_interpolator->addr);
-
-                case TIME_SOURCE_MMIO32 :
-                        return readl_relaxed((void __iomem *)time_interpolator->addr);
-
-                default: return get_cycles();
-        }
-}
-
-static inline u64 time_interpolator_get_counter(int writelock)
-{
-        unsigned int src = time_interpolator->source;
-
-        if (time_interpolator->jitter)
-        {
-                cycles_t lcycle;
-                cycles_t now;
-
-                do {
-                        lcycle = time_interpolator->last_cycle;
-                        now = time_interpolator_get_cycles(src);
-                        if (lcycle && time_after(lcycle, now))
-                                return lcycle;
-
-                        /* When holding the xtime write lock, there's no need
-                         * to add the overhead of the cmpxchg.  Readers are
-                         * force to retry until the write lock is released.
-                         */
-                        if (writelock) {
-                                time_interpolator->last_cycle = now;
-                                return now;
-                        }
-                        /* Keep track of the last timer value returned. The use of cmpxchg here
-                         * will cause contention in an SMP environment.
-                         */
-                } while (unlikely(cmpxchg(&time_interpolator->last_cycle, lcycle, now) != lcycle));
-                return now;
-        }
-        else
-                return time_interpolator_get_cycles(src);
-}
-
-void time_interpolator_reset(void)
-{
-        time_interpolator->offset = 0;
-        time_interpolator->last_counter = time_interpolator_get_counter(1);
-}
-
-#define GET_TI_NSECS(count,i) (((((count) - i->last_counter) & (i)->mask) * (i)->nsec_per_cyc) >> (i)->shift)
-
-unsigned long time_interpolator_get_offset(void)
-{
-        /* If we do not have a time interpolator set up then just return zero */
-        if (!time_interpolator)
-                return 0;
-
-        return time_interpolator->offset +
-                GET_TI_NSECS(time_interpolator_get_counter(0), time_interpolator);
-}
-
-#define INTERPOLATOR_ADJUST 65536
-#define INTERPOLATOR_MAX_SKIP 10*INTERPOLATOR_ADJUST
-
-void time_interpolator_update(long delta_nsec)
-{
-        u64 counter;
-        unsigned long offset;
-
-        /* If there is no time interpolator set up then do nothing */
-        if (!time_interpolator)
-                return;
-
-        /*
-         * The interpolator compensates for late ticks by accumulating the late
-         * time in time_interpolator->offset. A tick earlier than expected will
-         * lead to a reset of the offset and a corresponding jump of the clock
-         * forward. Again this only works if the interpolator clock is running
-         * slightly slower than the regular clock and the tuning logic insures
-         * that.
-         */
-
-        counter = time_interpolator_get_counter(1);
-        offset = time_interpolator->offset +
-                        GET_TI_NSECS(counter, time_interpolator);
-
-        if (delta_nsec < 0 || (unsigned long) delta_nsec < offset)
-                time_interpolator->offset = offset - delta_nsec;
-        else {
-                time_interpolator->skips++;
-                time_interpolator->ns_skipped += delta_nsec - offset;
-                time_interpolator->offset = 0;
-        }
-        time_interpolator->last_counter = counter;
-
-        /* Tuning logic for time interpolator invoked every minute or so.
-         * Decrease interpolator clock speed if no skips occurred and an offset is carried.
-         * Increase interpolator clock speed if we skip too much time.
-         */
-        if (jiffies % INTERPOLATOR_ADJUST == 0)
-        {
-                if (time_interpolator->skips == 0 && time_interpolator->offset > tick_nsec)
-                        time_interpolator->nsec_per_cyc--;
-                if (time_interpolator->ns_skipped > INTERPOLATOR_MAX_SKIP && time_interpolator->offset == 0)
-                        time_interpolator->nsec_per_cyc++;
-                time_interpolator->skips = 0;
-                time_interpolator->ns_skipped = 0;
-        }
-}
-
-static inline int
-is_better_time_interpolator(struct time_interpolator *new)
-{
-        if (!time_interpolator)
-                return 1;
-        return new->frequency > 2*time_interpolator->frequency ||
-            (unsigned long)new->drift < (unsigned long)time_interpolator->drift;
-}
-
-void
-register_time_interpolator(struct time_interpolator *ti)
-{
-        unsigned long flags;
-
-        /* Sanity check */
-        BUG_ON(ti->frequency == 0 || ti->mask == 0);
-
-        ti->nsec_per_cyc = ((u64)NSEC_PER_SEC << ti->shift) / ti->frequency;
-        spin_lock(&time_interpolator_lock);
-        write_seqlock_irqsave(&xtime_lock, flags);
-        if (is_better_time_interpolator(ti)) {
-                time_interpolator = ti;
-                time_interpolator_reset();
-        }
-        write_sequnlock_irqrestore(&xtime_lock, flags);
-
-        ti->next = time_interpolator_list;
-        time_interpolator_list = ti;
-        spin_unlock(&time_interpolator_lock);
-}
-
-void
-unregister_time_interpolator(struct time_interpolator *ti)
-{
-        struct time_interpolator *curr, **prev;
-        unsigned long flags;
-
-        spin_lock(&time_interpolator_lock);
-        prev = &time_interpolator_list;
-        for (curr = *prev; curr; curr = curr->next) {
-                if (curr == ti) {
-                        *prev = curr->next;
-                        break;
-                }
-                prev = &curr->next;
-        }
-
-        write_seqlock_irqsave(&xtime_lock, flags);
-        if (ti == time_interpolator) {
-                /* we lost the best time-interpolator: */
-                time_interpolator = NULL;
-                /* find the next-best interpolator */
-                for (curr = time_interpolator_list; curr; curr = curr->next)
-                        if (is_better_time_interpolator(curr))
-                                time_interpolator = curr;
-                time_interpolator_reset();
-        }
-        write_sequnlock_irqrestore(&xtime_lock, flags);
-        spin_unlock(&time_interpolator_lock);
-}
-#endif /* CONFIG_TIME_INTERPOLATION */
-
 /**
  * msleep - sleep safely even with waitqueue interruptions
  * @msecs: Time in milliseconds to sleep for