[PATCH 11/13] Time: x86-64 Conversion to Generic Timekeeping

john stultz
2005-11-12T04:50:15Z

All,
This patch converts the x86-64 arch to use the generic timeofday
infrastructure. It applies on top of my timeofday-core patch. This is a
full conversion, so most of this patch is subtractions removing the
existing arch specific time keeping code. This patch does not provide
any x86-64 clocksourcs, so using this patch alone on top of the
timeofday-core patch will only give you the jiffies clocksource. To get
full replacements for the code being removed here, the following
timeofday-clocks-i386 patch (x86-64 shares the same clocksources as
i386) will need to be applied.

thanks
-john

Signed-off-by: John Stultz <johnstul@us.ibm.com>

arch/x86_64/kernel/pmtimer.c | 101 -------
b/arch/i386/kernel/acpi/boot.c | 9
b/arch/x86_64/Kconfig | 8
b/arch/x86_64/kernel/Makefile | 1
b/arch/x86_64/kernel/time.c | 527 ++++++++++++++-----------------------
b/arch/x86_64/kernel/vmlinux.lds.S | 12
b/arch/x86_64/kernel/vsyscall.c | 126 ++++++--
b/include/asm-generic/div64.h | 9
b/include/asm-x86_64/hpet.h | 3
b/include/asm-x86_64/timeofday.h | 4
b/include/asm-x86_64/timex.h | 2
b/include/asm-x86_64/vsyscall.h | 8
12 files changed, 353 insertions(+), 457 deletions(-)

linux-2.6.14_timeofday-arch-x86-64_B10.patch
============================================
diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index bb9ecdc..972d66f 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -570,7 +570,7 @@ static int __init acpi_parse_sbf(unsigne
}

#ifdef CONFIG_HPET_TIMER
-
+#include <asm/hpet.h>
static int __init acpi_parse_hpet(unsigned long phys, unsigned long size)
{
struct acpi_table_hpet *hpet_tbl;
@@ -592,6 +592,7 @@ static int __init acpi_parse_hpet(unsign
#ifdef CONFIG_X86_64
vxtime.hpet_address = hpet_tbl->addr.addrl |
((long)hpet_tbl->addr.addrh << 32);
+ hpet_address = vxtime.hpet_address;

printk(KERN_INFO PREFIX "HPET id: %#x base: %#lx\n",
hpet_tbl->id, vxtime.hpet_address);
@@ -600,10 +601,10 @@ static int __init acpi_parse_hpet(unsign
extern unsigned long hpet_address;

hpet_address = hpet_tbl->addr.addrl;
- printk(KERN_INFO PREFIX "HPET id: %#x base: %#lx\n",
- hpet_tbl->id, hpet_address);
}
-#endif /* X86 */
+#endif /* X86 */
+ printk(KERN_INFO PREFIX "HPET id: %#x base: %#lx\n",
+ hpet_tbl->id, hpet_address);

return 0;
}
diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
index 4cce2f6..19b113e 100644
--- a/arch/x86_64/Kconfig
+++ b/arch/x86_64/Kconfig
@@ -24,6 +24,14 @@ config X86
bool
default y

+config GENERIC_TIME
+ bool
+ default y
+
+config GENERIC_TIME_VSYSCALL
+ bool
+ default y
+
config SEMAPHORE_SLEEPERS
bool
default y
diff --git a/arch/x86_64/kernel/Makefile b/arch/x86_64/kernel/Makefile
index 14328ca..0dd7b86 100644
--- a/arch/x86_64/kernel/Makefile
+++ b/arch/x86_64/kernel/Makefile
@@ -28,7 +28,6 @@ obj-$(CONFIG_EARLY_PRINTK) += early_prin
obj-$(CONFIG_GART_IOMMU) += pci-gart.o aperture.o
obj-$(CONFIG_DUMMY_IOMMU) += pci-nommu.o pci-dma.o
obj-$(CONFIG_KPROBES) += kprobes.o
-obj-$(CONFIG_X86_PM_TIMER) += pmtimer.o

obj-$(CONFIG_MODULES) += module.o

diff --git a/arch/x86_64/kernel/pmtimer.c b/arch/x86_64/kernel/pmtimer.c
deleted file mode 100644
index feb5f10..0000000
--- a/arch/x86_64/kernel/pmtimer.c
+++ /dev/null
@@ -1,101 +0,0 @@
-/* Ported over from i386 by AK, original copyright was:
- *
- * (C) Dominik Brodowski <linux@brodo.de> 2003
- *
- * Driver to use the Power Management Timer (PMTMR) available in some
- * southbridges as primary timing source for the Linux kernel.
- *
- * Based on parts of linux/drivers/acpi/hardware/hwtimer.c, timer_pit.c,
- * timer_hpet.c, and on Arjan van de Ven's implementation for 2.4.
- *
- * This file is licensed under the GPL v2.
- *
- * Dropped all the hardware bug workarounds for now. Hopefully they
- * are not needed on 64bit chipsets.
- */
-
-#include <linux/jiffies.h>
-#include <linux/kernel.h>
-#include <linux/time.h>
-#include <linux/init.h>
-#include <linux/cpumask.h>
-#include <asm/io.h>
-#include <asm/proto.h>
-#include <asm/msr.h>
-#include <asm/vsyscall.h>
-
-/* The I/O port the PMTMR resides at.
- * The location is detected during setup_arch(),
- * in arch/i386/kernel/acpi/boot.c */
-u32 pmtmr_ioport;
-
-/* value of the Power timer at last timer interrupt */
-static u32 offset_delay;
-static u32 last_pmtmr_tick;
-
-#define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */
-
-static inline u32 cyc2us(u32 cycles)
-{
- /* The Power Management Timer ticks at 3.579545 ticks per microsecond.
- * 1 / PM_TIMER_FREQUENCY == 0.27936511 =~ 286/1024 [error: 0.024%]
- *
- * Even with HZ = 100, delta is at maximum 35796 ticks, so it can
- * easily be multiplied with 286 (=0x11E) without having to fear
- * u32 overflows.
- */
- cycles *= 286;
- return (cycles >> 10);
-}
-
-int pmtimer_mark_offset(void)
-{
- static int first_run = 1;
- unsigned long tsc;
- u32 lost;
-
- u32 tick = inl(pmtmr_ioport);
- u32 delta;
-
- delta = cyc2us((tick - last_pmtmr_tick) & ACPI_PM_MASK);
-
- last_pmtmr_tick = tick;
- monotonic_base += delta * NSEC_PER_USEC;
-
- delta += offset_delay;
-
- lost = delta / (USEC_PER_SEC / HZ);
- offset_delay = delta % (USEC_PER_SEC / HZ);
-
- rdtscll(tsc);
- vxtime.last_tsc = tsc - offset_delay * cpu_khz;
-
- /* don't calculate delay for first run,
- or if we've got less then a tick */
- if (first_run || (lost < 1)) {
- first_run = 0;
- offset_delay = 0;
- }
-
- return lost - 1;
-}
-
-unsigned int do_gettimeoffset_pm(void)
-{
- u32 now, offset, delta = 0;
-
- offset = last_pmtmr_tick;
- now = inl(pmtmr_ioport);
- delta = (now - offset) & ACPI_PM_MASK;
-
- return offset_delay + cyc2us(delta);
-}
-
-
-static int __init nopmtimer_setup(char *s)
-{
- pmtmr_ioport = 0;
- return 0;
-}
-
-__setup("nopmtimer", nopmtimer_setup);
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 4b80b4a..3a44861 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -38,13 +38,11 @@
#include <asm/sections.h>
#include <linux/cpufreq.h>
#include <linux/hpet.h>
+#include <linux/timeofday.h>
#ifdef CONFIG_X86_LOCAL_APIC
#include <asm/apic.h>
#endif

-#ifdef CONFIG_CPU_FREQ
-static void cpufreq_delayed_get(void);
-#endif
extern void i8254_timer_resume(void);
extern int using_apic_timer;

@@ -56,7 +54,9 @@ static int notsc __initdata = 0;

#undef HPET_HACK_ENABLE_DANGEROUS

-unsigned int cpu_khz; /* TSC clocks / usec, not used here */
+unsigned int cpu_khz; /* CPU clocks / usec, not used here */
+unsigned int tsc_khz; /* TSC clocks / usec, not used here */
+unsigned long hpet_address;
static unsigned long hpet_period; /* fsecs / HPET clock */
unsigned long hpet_tick; /* HPET clocks / interrupt */
static int hpet_use_timer;
@@ -79,112 +79,6 @@ static inline void rdtscll_sync(unsigned
rdtscll(*tsc);
}

-static inline unsigned long fixed_hpet_tick(void)
-{
- return hpet_tick ? hpet_tick : 1;
-}
-
-/*
- * do_gettimeoffset() returns microseconds since last timer interrupt was
- * triggered by hardware. A memory read of HPET is slower than a register read
- * of TSC, but much more reliable. It's also synchronized to the timer
- * interrupt. Note that do_gettimeoffset() may return more than hpet_tick, if a
- * timer interrupt has happened already, but vxtime.trigger wasn't updated yet.
- * This is not a problem, because jiffies hasn't updated either. They are bound
- * together by xtime_lock.
- */
-
-static inline unsigned int do_gettimeoffset_tsc(void)
-{
- unsigned long t;
- unsigned long x;
- rdtscll_sync(&t);
- if (t < vxtime.last_tsc) t = vxtime.last_tsc; /* hack */
- x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> 32;
- return x;
-}
-
-static inline unsigned int do_gettimeoffset_hpet(void)
-{
- /* cap counter read to one tick to avoid inconsistencies */
- unsigned long counter = hpet_readl(HPET_COUNTER) - vxtime.last;
- return (min(counter,hpet_tick) * vxtime.quot) >> 32;
-}
-
-unsigned int (*do_gettimeoffset)(void) = do_gettimeoffset_tsc;
-
-/*
- * This version of gettimeofday() has microsecond resolution and better than
- * microsecond precision, as we're using at least a 10 MHz (usually 14.31818
- * MHz) HPET timer.
- */
-
-void do_gettimeofday(struct timeval *tv)
-{
- unsigned long seq, t;
- unsigned int sec, usec;
-
- do {
- seq = read_seqbegin(&xtime_lock);
-
- sec = xtime.tv_sec;
- usec = xtime.tv_nsec / 1000;
-
- /* i386 does some correction here to keep the clock
- monotonous even when ntpd is fixing drift.
- But they didn't work for me, there is a non monotonic
- clock anyways with ntp.
- I dropped all corrections now until a real solution can
- be found. Note when you fix it here you need to do the same
- in arch/x86_64/kernel/vsyscall.c and export all needed
- variables in vmlinux.lds. -AK */
-
- t = (jiffies - wall_jiffies) * (1000000L / HZ) +
- do_gettimeoffset();
- usec += t;
-
- } while (read_seqretry(&xtime_lock, seq));
-
- tv->tv_sec = sec + usec / 1000000;
- tv->tv_usec = usec % 1000000;
-}
-
-EXPORT_SYMBOL(do_gettimeofday);
-
-/*
- * settimeofday() first undoes the correction that gettimeofday would do
- * on the time, and then saves it. This is ugly, but has been like this for
- * ages already.
- */
-
-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);
-
- nsec -= do_gettimeoffset() * 1000 +
- (jiffies - wall_jiffies) * (NSEC_PER_SEC/HZ);
-
- 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);
-
- ntp_clear();
-
- write_sequnlock_irq(&xtime_lock);
- clock_was_set();
- return 0;
-}
-
-EXPORT_SYMBOL(do_settimeofday);
-
unsigned long profile_pc(struct pt_regs *regs)
{
unsigned long pc = instruction_pointer(regs);
@@ -284,90 +178,8 @@ static void set_rtc_mmss(unsigned long n
spin_unlock(&rtc_lock);
}

-
-/* monotonic_clock(): returns # of nanoseconds passed since time_init()
- * Note: This function is required to return accurate
- * time even in the absence of multiple timer ticks.
- */
-unsigned long long monotonic_clock(void)
-{
- unsigned long seq;
- u32 last_offset, this_offset, offset;
- unsigned long long base;
-
- if (vxtime.mode == VXTIME_HPET) {
- do {
- seq = read_seqbegin(&xtime_lock);
-
- last_offset = vxtime.last;
- base = monotonic_base;
- this_offset = hpet_readl(HPET_COUNTER);
-
- } while (read_seqretry(&xtime_lock, seq));
- offset = (this_offset - last_offset);
- offset *=(NSEC_PER_SEC/HZ)/fixed_hpet_tick();
- return base + offset;
- }else{
- do {
- seq = read_seqbegin(&xtime_lock);
-
- last_offset = vxtime.last_tsc;
- base = monotonic_base;
- } while (read_seqretry(&xtime_lock, seq));
- sync_core();
- rdtscll(this_offset);
- offset = (this_offset - last_offset)*1000/cpu_khz;
- return base + offset;
- }
-
-
-}
-EXPORT_SYMBOL(monotonic_clock);
-
-static noinline void handle_lost_ticks(int lost, struct pt_regs *regs)
-{
- static long lost_count;
- static int warned;
-
- if (report_lost_ticks) {
- printk(KERN_WARNING "time.c: Lost %d timer "
- "tick(s)! ", lost);
- print_symbol("rip %s)\n", regs->rip);
- }
-
- if (lost_count == 1000 && !warned) {
- printk(KERN_WARNING
- "warning: many lost ticks.\n"
- KERN_WARNING "Your time source seems to be instable or "
- "some driver is hogging interupts\n");
- print_symbol("rip %s\n", regs->rip);
- if (vxtime.mode == VXTIME_TSC && vxtime.hpet_address) {
- printk(KERN_WARNING "Falling back to HPET\n");
- vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
- vxtime.mode = VXTIME_HPET;
- do_gettimeoffset = do_gettimeoffset_hpet;
- }
- /* else should fall back to PIT, but code missing. */
- warned = 1;
- } else
- lost_count++;
-
-#ifdef CONFIG_CPU_FREQ
- /* In some cases the CPU can change frequency without us noticing
- (like going into thermal throttle)
- Give cpufreq a change to catch up. */
- if ((lost_count+1) % 25 == 0) {
- cpufreq_delayed_get();
- }
-#endif
-}
-
static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
- static unsigned long rtc_update = 0;
- unsigned long tsc;
- int delay, offset = 0, lost = 0;
-
/*
* Here we are in the timer irq handler. We have irqs locally disabled (so we
* don't need spin_lock_irqsave()) but we don't know if the timer_bh is running
@@ -377,67 +189,6 @@ static irqreturn_t timer_interrupt(int i

write_seqlock(&xtime_lock);

- if (vxtime.hpet_address)
- offset = hpet_readl(HPET_COUNTER);
-
- if (hpet_use_timer) {
- /* if we're using the hpet timer functionality,
- * we can more accurately know the counter value
- * when the timer interrupt occured.
- */
- offset = hpet_readl(HPET_T0_CMP) - hpet_tick;
- delay = hpet_readl(HPET_COUNTER) - offset;
- } else {
- spin_lock(&i8253_lock);
- outb_p(0x00, 0x43);
- delay = inb_p(0x40);
- delay |= inb(0x40) << 8;
- spin_unlock(&i8253_lock);
- delay = LATCH - 1 - delay;
- }
-
- rdtscll_sync(&tsc);
-
- if (vxtime.mode == VXTIME_HPET) {
- if (offset - vxtime.last > hpet_tick) {
- lost = (offset - vxtime.last) / fixed_hpet_tick() - 1;
- }
-
- monotonic_base += (offset - vxtime.last)*(NSEC_PER_SEC/HZ) /
- fixed_hpet_tick();
-
- vxtime.last = offset;
-#ifdef CONFIG_X86_PM_TIMER
- } else if (vxtime.mode == VXTIME_PMTMR) {
- lost = pmtimer_mark_offset();
-#endif
- } else {
- offset = (((tsc - vxtime.last_tsc) *
- vxtime.tsc_quot) >> 32) - (USEC_PER_SEC / HZ);
-
- if (offset < 0)
- offset = 0;
-
- if (offset > (USEC_PER_SEC / HZ)) {
- lost = offset / (USEC_PER_SEC / HZ);
- offset %= (USEC_PER_SEC / HZ);
- }
-
- monotonic_base += (tsc - vxtime.last_tsc)*1000000/cpu_khz ;
-
- vxtime.last_tsc = tsc - vxtime.quot * delay / vxtime.tsc_quot;
-
- if ((((tsc - vxtime.last_tsc) *
- vxtime.tsc_quot) >> 32) < offset)
- vxtime.last_tsc = tsc -
- (((long) offset << 32) / vxtime.tsc_quot) - 1;
- }
-
- if (lost > 0) {
- handle_lost_ticks(lost, regs);
- jiffies += lost;
- }
-
/*
* Do the timer stuff.
*/
@@ -460,20 +211,6 @@ static irqreturn_t timer_interrupt(int i
smp_local_timer_interrupt(regs);
#endif

-/*
- * If we have an externally synchronized Linux clock, then update CMOS clock
- * accordingly every ~11 minutes. set_rtc_mmss() will be called in the jiffy
- * closest to exactly 500 ms before the next second. If the update fails, we
- * don't care, as it'll be updated on the next turn, and the problem (time way
- * off) isn't likely to go away much sooner anyway.
- */
-
- if (ntp_synced() && xtime.tv_sec > rtc_update &&
- abs(xtime.tv_nsec - 500000000) <= tick_nsec / 2) {
- set_rtc_mmss(xtime.tv_sec);
- rtc_update = xtime.tv_sec + 660;
- }
-
write_sequnlock(&xtime_lock);

return IRQ_HANDLED;
@@ -514,6 +251,29 @@ unsigned long long sched_clock(void)
return cycles_2_ns(a);
}

+/* Code to compensate for TSC C3 stalls */
+static u64 tsc_c3_offset;
+static int tsc_unstable;
+static inline int check_tsc_unstable(void)
+{
+ return tsc_unstable;
+}
+static inline void mark_tsc_unstable(void)
+{
+ tsc_unstable = 1;;
+}
+
+void tsc_c3_compensate(unsigned long nsecs)
+{
+ u64 cycles = ((u64)nsecs * tsc_khz)/1000000;
+ tsc_c3_offset += cycles;
+}
+
+static inline u64 tsc_read_c3_time(void)
+{
+ return tsc_c3_offset;
+}
+
unsigned long get_cmos_time(void)
{
unsigned int timeout, year, mon, day, hour, min, sec;
@@ -574,6 +334,30 @@ unsigned long get_cmos_time(void)
return mktime(year, mon, day, hour, min, sec);
}

+/* arch specific timeofday hooks */
+u64 read_persistent_clock(void)
+{
+ return (u64)get_cmos_time() * NSEC_PER_SEC;
+}
+
+void sync_persistent_clock(struct timespec ts)
+{
+ static unsigned long rtc_update = 0;
+ /*
+ * If we have an externally synchronized Linux clock, then update
+ * CMOS clock accordingly every ~11 minutes. set_rtc_mmss() will
+ * be called in the jiffy closest to exactly 500 ms before the
+ * next second. If the update fails, we don't care, as it'll be
+ * updated on the next turn, and the problem (time way off) isn't
+ * likely to go away much sooner anyway.
+ */
+ if (ts.tv_sec > rtc_update &&
+ abs(ts.tv_nsec - 500000000) <= tick_nsec / 2) {
+ set_rtc_mmss(xtime.tv_sec);
+ rtc_update = xtime.tv_sec + 660;
+ }
+}
+
#ifdef CONFIG_CPU_FREQ

/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
@@ -601,23 +385,6 @@ static void handle_cpufreq_delayed_get(v
cpufreq_delayed_issched = 0;
}

-/* if we notice lost ticks, schedule a call to cpufreq_get() as it tries
- * to verify the CPU frequency the timing core thinks the CPU is running
- * at is still correct.
- */
-static void cpufreq_delayed_get(void)
-{
- static int warned;
- if (cpufreq_init && !cpufreq_delayed_issched) {
- cpufreq_delayed_issched = 1;
- if (!warned) {
- warned = 1;
- printk(KERN_DEBUG "Losing some ticks... checking if CPU frequency changed.\n");
- }
- schedule_work(&cpufreq_delayed_get_work);
- }
-}
-
static unsigned int ref_freq = 0;
static unsigned long loops_per_jiffy_ref = 0;

@@ -652,8 +419,11 @@ static int time_cpufreq_notifier(struct
cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);

cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
- if (!(freq->flags & CPUFREQ_CONST_LOOPS))
+ if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
vxtime.tsc_quot = (1000L << 32) / cpu_khz;
+ tsc_khz = cpu_khz;
+ }
+
}

set_cyc2ns_scale(cpu_khz_ref);
@@ -917,18 +687,12 @@ void __init time_init(void)
if (hpet_use_timer) {
cpu_khz = hpet_calibrate_tsc();
timename = "HPET";
-#ifdef CONFIG_X86_PM_TIMER
- } else if (pmtmr_ioport) {
- vxtime_hz = PM_TIMER_FREQUENCY;
- timename = "PM";
- pit_init();
- cpu_khz = pit_calibrate_tsc();
-#endif
} else {
pit_init();
cpu_khz = pit_calibrate_tsc();
timename = "PIT";
}
+ tsc_khz = cpu_khz;

printk(KERN_INFO "time.c: Using %ld.%06ld MHz %s timer.\n",
vxtime_hz / 1000000, vxtime_hz % 1000000, timename);
@@ -970,31 +734,8 @@ static __init int unsynchronized_tsc(voi
*/
void __init time_init_gtod(void)
{
- char *timetype;
-
if (unsynchronized_tsc())
- notsc = 1;
- if (vxtime.hpet_address && notsc) {
- timetype = hpet_use_timer ? "HPET" : "PIT/HPET";
- vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
- vxtime.mode = VXTIME_HPET;
- do_gettimeoffset = do_gettimeoffset_hpet;
-#ifdef CONFIG_X86_PM_TIMER
- /* Using PM for gettimeofday is quite slow, but we have no other
- choice because the TSC is too unreliable on some systems. */
- } else if (pmtmr_ioport && !vxtime.hpet_address && notsc) {
- timetype = "PM";
- do_gettimeoffset = do_gettimeoffset_pm;
- vxtime.mode = VXTIME_PMTMR;
- sysctl_vsyscall = 0;
- printk(KERN_INFO "Disabling vsyscall due to use of PM timer\n");
-#endif
- } else {
- timetype = hpet_use_timer ? "HPET/TSC" : "PIT/TSC";
- vxtime.mode = VXTIME_TSC;
- }
-
- printk(KERN_INFO "time.c: Using %s based timekeeping.\n", timetype);
+ mark_tsc_unstable();
}

__setup("report_lost_ticks", time_setup);
@@ -1017,7 +758,6 @@ static int timer_suspend(struct sys_devi

static int timer_resume(struct sys_device *dev)
{
- unsigned long flags;
unsigned long sec;
unsigned long ctime = get_cmos_time();
unsigned long sleep_length = (ctime - sleep_start) * HZ;
@@ -1028,10 +768,6 @@ static int timer_resume(struct sys_devic
i8254_timer_resume();

sec = ctime + clock_cmos_diff;
- write_seqlock_irqsave(&xtime_lock,flags);
- xtime.tv_sec = sec;
- xtime.tv_nsec = 0;
- write_sequnlock_irqrestore(&xtime_lock,flags);
jiffies += sleep_length;
wall_jiffies += sleep_length;
touch_softlockup_watchdog();
@@ -1308,3 +1044,152 @@ static int __init notsc_setup(char *s)
__setup("notsc", notsc_setup);

+/* Clock source code */
+#include <linux/clocksource.h>
+#include <asm/vsyscall.h>
+
+static unsigned long current_tsc_khz = 0;
+static int tsc_update_callback(void);
+
+static cycle_t read_tsc(void)
+{
+ cycle_t ret;
+ rdtscll(ret);
+ return ret;
+}
+
+static cycle_t __vsyscall_fn vread_tsc(void* unused)
+{
+ cycle_t ret;
+ rdtscll(ret);
+ return ret;
+}
+
+static cycle_t read_tsc_c3(void)
+{
+ cycle_t ret;
+ rdtscll(ret);
+ return ret + tsc_read_c3_time();
+}
+
+static struct clocksource clocksource_tsc = {
+ .name = "tsc",
+ .rating = 300,
+ .read = read_tsc,
+ .vread = vread_tsc,
+ .mask = (cycle_t)-1,
+ .mult = 0, /* to be set */
+ .shift = 22,
+ .update_callback = tsc_update_callback,
+ .is_continuous = 1,
+};
+
+
+static int tsc_update_callback(void)
+{
+ int change = 0;
+ /* check to see if we should switch to the safe clocksource */
+ if (tsc_read_c3_time() &&
+ strncmp(clocksource_tsc.name, "c3tsc", 5)) {
+ printk("Falling back to C3 safe TSC\n");
+ clocksource_tsc.read = read_tsc_c3;
+ clocksource_tsc.vread = 0;
+ clocksource_tsc.name = "c3tsc";
+ change = 1;
+ }
+
+ if (clocksource_tsc.rating != 50 && check_tsc_unstable()) {
+ clocksource_tsc.rating = 50;
+ reselect_clocksource();
+ change = 1;
+ }
+ /* only update if tsc_khz has changed */
+ if (current_tsc_khz != tsc_khz){
+ current_tsc_khz = tsc_khz;
+ clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+ clocksource_tsc.shift);
+ change = 1;
+ }
+ return change;
+}
+
+static int __init init_tsc_clocksource(void)
+{
+ if (!notsc && tsc_khz) {
+ current_tsc_khz = tsc_khz;
+ clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+ clocksource_tsc.shift);
+ register_clocksource(&clocksource_tsc);
+ }
+ return 0;
+}
+
+module_init(init_tsc_clocksource);
+
+
+#define HPET_MASK (0xFFFFFFFF)
+#define HPET_SHIFT 22
+
+/* FSEC = 10^-15 NSEC = 10^-9 */
+#define FSEC_PER_NSEC 1000000
+
+
+static void *hpet_ptr;
+
+static cycle_t read_hpet(void)
+{
+ return (cycle_t)readl(hpet_ptr);
+}
+
+static cycle_t __vsyscall_fn vread_hpet(void* ptr)
+{
+ return (cycle_t)readl((void *)fix_to_virt(VSYSCALL_HPET) + 0xf0);
+}
+
+struct clocksource clocksource_hpet = {
+ .name = "hpet",
+ .rating = 250,
+ .read = read_hpet,
+ .vread = vread_hpet,
+ .mask = (cycle_t)HPET_MASK,
+ .mult = 0, /* set below */
+ .shift = HPET_SHIFT,
+ .is_continuous = 1,
+};
+
+static int __init init_hpet_clocksource(void)
+{
+ unsigned long hpet_period;
+ void __iomem* hpet_base;
+ u64 tmp;
+
+ if (!hpet_address)
+ return -ENODEV;
+
+ /* calculate the hpet address */
+ hpet_base =
+ (void __iomem*)ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
+ hpet_ptr = hpet_base + HPET_COUNTER;
+
+ /* calculate the frequency */
+ hpet_period = readl(hpet_base + HPET_PERIOD);
+
+
+ /* hpet period is in femto seconds per cycle
+ * so we need to convert this to ns/cyc units
+ * aproximated by mult/2^shift
+ *
+ * fsec/cyc * 1nsec/1000000fsec = nsec/cyc = mult/2^shift
+ * fsec/cyc * 1ns/1000000fsec * 2^shift = mult
+ * fsec/cyc * 2^shift * 1nsec/1000000fsec = mult
+ * (fsec/cyc << shift)/1000000 = mult
+ * (hpet_period << shift)/FSEC_PER_NSEC = mult
+ */
+ tmp = (u64)hpet_period << HPET_SHIFT;
+ do_div(tmp, FSEC_PER_NSEC);
+ clocksource_hpet.mult = (u32)tmp;
+
+ register_clocksource(&clocksource_hpet);
+ return 0;
+}
+module_init(init_hpet_clocksource);
diff --git a/arch/x86_64/kernel/vmlinux.lds.S b/arch/x86_64/kernel/vmlinux.lds.S
index 6dd642c..7559b94 100644
--- a/arch/x86_64/kernel/vmlinux.lds.S
+++ b/arch/x86_64/kernel/vmlinux.lds.S
@@ -99,6 +99,18 @@ SECTIONS
.jiffies : AT(VLOAD(.jiffies)) { *(.jiffies) }
jiffies = VVIRT(.jiffies);

+ .vsyscall_fn : AT(VLOAD(.vsyscall_fn)) { *(.vsyscall_fn) }
+ .vsyscall_data : AT(VLOAD(.vsyscall_data)) { *(.vsyscall_data) }
+
+ .vsyscall_gtod_data : AT(VLOAD(.vsyscall_gtod_data)) { *(.vsyscall_gtod_data) }
+ vsyscall_gtod_data = VVIRT(.vsyscall_gtod_data);
+
+ .vsyscall_gtod_lock : AT(VLOAD(.vsyscall_gtod_lock)) { *(.vsyscall_gtod_lock) }
+ vsyscall_gtod_lock = VVIRT(.vsyscall_gtod_lock);
+
+ .vsyscall_fn : AT(VLOAD(.vsyscall_fn)) { *(.vsyscall_fn) }
+ .vsyscall_data : AT(VLOAD(.vsyscall_data)) { *(.vsyscall_data) }
+
.vsyscall_1 ADDR(.vsyscall_0) + 1024: AT(VLOAD(.vsyscall_1)) { *(.vsyscall_1) }
.vsyscall_2 ADDR(.vsyscall_0) + 2048: AT(VLOAD(.vsyscall_2)) { *(.vsyscall_2) }
.vsyscall_3 ADDR(.vsyscall_0) + 3072: AT(VLOAD(.vsyscall_3)) { *(.vsyscall_3) }
diff --git a/arch/x86_64/kernel/vsyscall.c b/arch/x86_64/kernel/vsyscall.c
index 70a0bd1..5b5d337 100644
--- a/arch/x86_64/kernel/vsyscall.c
+++ b/arch/x86_64/kernel/vsyscall.c
@@ -19,6 +19,8 @@
* want per guest time just set the kernel.vsyscall64 sysctl to 0.
*/

+#include <linux/timeofday.h>
+#include <linux/clocksource.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/kernel.h>
@@ -40,6 +42,21 @@
int __sysctl_vsyscall __section_sysctl_vsyscall = 1;
seqlock_t __xtime_lock __section_xtime_lock = SEQLOCK_UNLOCKED;

+
+struct vsyscall_gtod_data_t {
+ struct timeval wall_time_tv;
+ struct timezone sys_tz;
+ cycle_t offset_base;
+ struct clocksource clock;
+};
+
+extern struct vsyscall_gtod_data_t vsyscall_gtod_data;
+struct vsyscall_gtod_data_t __vsyscall_gtod_data __section_vsyscall_gtod_data;
+
+extern seqlock_t vsyscall_gtod_lock;
+seqlock_t __vsyscall_gtod_lock __section_vsyscall_gtod_lock = SEQLOCK_UNLOCKED;
+
+
#include <asm/unistd.h>

static force_inline void timeval_normalize(struct timeval * tv)
@@ -53,40 +70,56 @@ static force_inline void timeval_normali
}
}

-static force_inline void do_vgettimeofday(struct timeval * tv)
+/* XXX - this is ugly. gettimeofday() has a label in it so we can't
+ call it twice.
+ */
+static force_inline int syscall_gtod(struct timeval *tv, struct timezone *tz)
{
- long sequence, t;
- unsigned long sec, usec;
-
+ int ret;
+ asm volatile("syscall"
+ : "=a" (ret)
+ : "0" (__NR_gettimeofday),"D" (tv),"S" (tz) : __syscall_clobber );
+ return ret;
+}
+static force_inline void do_vgettimeofday(struct timeval* tv)
+{
+ cycle_t now, cycle_delta;
+ nsec_t nsec_delta;
+ unsigned long seq;
do {
- sequence = read_seqbegin(&__xtime_lock);
-
- sec = __xtime.tv_sec;
- usec = (__xtime.tv_nsec / 1000) +
- (__jiffies - __wall_jiffies) * (1000000 / HZ);
-
- if (__vxtime.mode != VXTIME_HPET) {
- sync_core();
- rdtscll(t);
- if (t < __vxtime.last_tsc)
- t = __vxtime.last_tsc;
- usec += ((t - __vxtime.last_tsc) *
- __vxtime.tsc_quot) >> 32;
- /* See comment in x86_64 do_gettimeofday. */
- } else {
- usec += ((readl((void *)fix_to_virt(VSYSCALL_HPET) + 0xf0) -
- __vxtime.last) * __vxtime.quot) >> 32;
+ seq = read_seqbegin(&__vsyscall_gtod_lock);
+
+ if (!__vsyscall_gtod_data.clock.vread) {
+ syscall_gtod(tv, NULL);
+ return;
}
- } while (read_seqretry(&__xtime_lock, sequence));

- tv->tv_sec = sec + usec / 1000000;
- tv->tv_usec = usec % 1000000;
+ /* read the timeosurce and calc cycle_delta */
+ now = __vsyscall_gtod_data.clock.vread(
+ __vsyscall_gtod_data.clock.vdata);
+
+ cycle_delta = (now - __vsyscall_gtod_data.offset_base)
+ & __vsyscall_gtod_data.clock.mask;
+
+ /* convert cycles to nsecs */
+ nsec_delta = cycle_delta * __vsyscall_gtod_data.clock.mult;
+ nsec_delta = nsec_delta >> __vsyscall_gtod_data.clock.shift;
+
+ /* add nsec offset to wall_time_tv */
+ *tv = __vsyscall_gtod_data.wall_time_tv;
+ do_div(nsec_delta, NSEC_PER_USEC);
+ tv->tv_usec += (unsigned long) nsec_delta;
+ while (tv->tv_usec > USEC_PER_SEC) {
+ tv->tv_sec += 1;
+ tv->tv_usec -= USEC_PER_SEC;
+ }
+ } while (read_seqretry(&__vsyscall_gtod_lock, seq));
}

/* RED-PEN may want to readd seq locking, but then the variable should be write-once. */
static force_inline void do_get_tz(struct timezone * tz)
{
- *tz = __sys_tz;
+ *tz = __vsyscall_gtod_data.sys_tz;
}

static force_inline int gettimeofday(struct timeval *tv, struct timezone *tz)
@@ -122,11 +155,13 @@ int __vsyscall(0) vgettimeofday(struct t
* unlikely */
time_t __vsyscall(1) vtime(time_t *t)
{
+ struct timeval tv;
if (unlikely(!__sysctl_vsyscall))
return time_syscall(t);
- else if (t)
- *t = __xtime.tv_sec;
- return __xtime.tv_sec;
+ vgettimeofday(&tv, 0);
+ if (t)
+ *t = tv.tv_sec;
+ return tv.tv_sec;
}

long __vsyscall(2) venosys_0(void)
@@ -139,6 +174,40 @@ long __vsyscall(3) venosys_1(void)
return -ENOSYS;
}

+struct clocksource* curr_clock;
+
+void arch_update_vsyscall_gtod(struct timespec wall_time, cycle_t offset_base,
+ struct clocksource *clock, int ntp_adj)
+{
+ unsigned long flags;
+
+ write_seqlock_irqsave(&vsyscall_gtod_lock, flags);
+
+ /* XXX - hackitty hack hack. this is terrible! */
+ if (curr_clock != clock) {
+ curr_clock = clock;
+ }
+
+ /* save off wall time as timeval */
+ vsyscall_gtod_data.wall_time_tv.tv_sec = wall_time.tv_sec;
+ vsyscall_gtod_data.wall_time_tv.tv_usec = wall_time.tv_nsec/1000;
+
+ /* save offset_base */
+ vsyscall_gtod_data.offset_base = offset_base;
+
+ /* copy current clocksource */
+ vsyscall_gtod_data.clock = *clock;
+
+ /* apply ntp adjustment to clocksource mult */
+ vsyscall_gtod_data.clock.mult += ntp_adj;
+
+ /* save off current timezone */
+ vsyscall_gtod_data.sys_tz = sys_tz;
+
+ write_sequnlock_irqrestore(&vsyscall_gtod_lock, flags);
+
+}
+
#ifdef CONFIG_SYSCTL

#define SYSCALL 0x050f
@@ -217,6 +286,7 @@ static int __init vsyscall_init(void)
BUG_ON((unsigned long) &vtime != VSYSCALL_ADDR(__NR_vtime));
BUG_ON((VSYSCALL_ADDR(0) != __fix_to_virt(VSYSCALL_FIRST_PAGE)));
map_vsyscall();
+ sysctl_vsyscall = 1;
#ifdef CONFIG_SYSCTL
register_sysctl_table(kernel_root_table2, 0);
#endif
diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
index 8f4e319..910a0fe 100644
--- a/include/asm-generic/div64.h
+++ b/include/asm-generic/div64.h
@@ -55,4 +55,13 @@ extern uint32_t __div64_32(uint64_t *div

#endif /* BITS_PER_LONG */

+#ifndef div_long_long_rem
+#define div_long_long_rem(dividend,divisor,remainder) \
+({ \
+ u64 result = dividend; \
+ *remainder = do_div(result,divisor); \
+ result; \
+})
+#endif
+
#endif /* _ASM_GENERIC_DIV64_H */
diff --git a/include/asm-x86_64/hpet.h b/include/asm-x86_64/hpet.h
index a3877f5..c8420bb 100644
--- a/include/asm-x86_64/hpet.h
+++ b/include/asm-x86_64/hpet.h
@@ -1,6 +1,6 @@
#ifndef _ASM_X8664_HPET_H
#define _ASM_X8664_HPET_H 1
-
+#include <asm/fixmap.h>
/*
* Documentation on HPET can be found at:
* http://www.intel.com/ial/home/sp/pcmmspec.htm
@@ -44,6 +44,7 @@
#define HPET_TN_SETVAL 0x040
#define HPET_TN_32BIT 0x100

+extern unsigned long hpet_address; /* hpet memory map physical address */
extern int is_hpet_enabled(void);
extern int hpet_rtc_timer_init(void);
extern int oem_force_hpet_timer(void);
diff --git a/include/asm-x86_64/timeofday.h b/include/asm-x86_64/timeofday.h
new file mode 100644
index 0000000..b344c0e
--- /dev/null
+++ b/include/asm-x86_64/timeofday.h
@@ -0,0 +1,4 @@
+#ifndef _ASM_X86_64_TIMEOFDAY_H
+#define _ASM_X86_64_TIMEOFDAY_H
+#include <asm-generic/timeofday.h>
+#endif
diff --git a/include/asm-x86_64/timex.h b/include/asm-x86_64/timex.h
index f971f45..a2da183 100644
--- a/include/asm-x86_64/timex.h
+++ b/include/asm-x86_64/timex.h
@@ -24,6 +24,8 @@ static inline cycles_t get_cycles (void)
}

extern unsigned int cpu_khz;
+extern unsigned int tsc_khz;
+extern void tsc_c3_compensate(unsigned long usecs);

extern int read_current_timer(unsigned long *timer_value);
#define ARCH_HAS_READ_CURRENT_TIMER 1
diff --git a/include/asm-x86_64/vsyscall.h b/include/asm-x86_64/vsyscall.h
index 438a3f5..2fe714c 100644
--- a/include/asm-x86_64/vsyscall.h
+++ b/include/asm-x86_64/vsyscall.h
@@ -14,7 +14,7 @@ enum vsyscall_num {
#define VSYSCALL_ADDR(vsyscall_nr) (VSYSCALL_START+VSYSCALL_SIZE*(vsyscall_nr))

#ifdef __KERNEL__
-
+/* XXX - All of these are unused w/ CONFIG_GENERIC_TIME and should be removed */
#define __section_vxtime __attribute__ ((unused, __section__ (".vxtime"), aligned(16)))
#define __section_wall_jiffies __attribute__ ((unused, __section__ (".wall_jiffies"), aligned(16)))
#define __section_jiffies __attribute__ ((unused, __section__ (".jiffies"), aligned(16)))
@@ -23,6 +23,12 @@ enum vsyscall_num {
#define __section_xtime __attribute__ ((unused, __section__ (".xtime"), aligned(16)))
#define __section_xtime_lock __attribute__ ((unused, __section__ (".xtime_lock"), aligned(16)))

+/* Definitions for CONFIG_GENERIC_TIME definitions */
+#define __section_vsyscall_gtod_data __attribute__ ((unused, __section__ (".vsyscall_gtod_data"),aligned(16)))
+#define __section_vsyscall_gtod_lock __attribute__ ((unused, __section__ (".vsyscall_gtod_lock"),aligned(16)))
+#define __vsyscall_fn __attribute__ ((unused,__section__(".vsyscall_fn")))
+#define __vsyscall_data __attribute__ ((unused,__section__(".vsyscall_data")))
+
#define VXTIME_TSC 1
#define VXTIME_HPET 2
#define VXTIME_PMTMR 3