Re: [PATCH] New x86_64 time code for 2.5.70

[Vojtech Pavlik <vojtech@ucw.cz>]

On Thu, Jun 12, 2003 at 10:47:10AM -0700, Bryan O'Sullivan wrote:
> On Wed, 2003-06-11 at 17:33, john stultz wrote:
> 
> > Let me know if you have any issues with this patch. 
> 
> Thanks, John.  Your updated patch has survived some beating on my test
> systems.  I've also applied Vojtech's fix to hpet_tick.
> 
> The latest grand unified x86_64 time patch against 2.5.70 is attached.

This one looks very good indeed. Andi?

> 
> 	<b
> 
>  arch/x86_64/Kconfig              |   12 +
>  arch/x86_64/kernel/acpi/boot.c   |    6
>  arch/x86_64/kernel/apic.c        |   84 +++++-----
>  arch/x86_64/kernel/smpboot.c     |   11 +
>  arch/x86_64/kernel/time.c        |  306 +++++++++++++++++++++++++++++++-------- arch/x86_64/kernel/vsyscall.c    |   28 ++-
>  arch/x86_64/vmlinux.lds.S        |    6
>  include/asm-x86_64/fixmap.h      |    2
>  include/asm-x86_64/mc146818rtc.h |    5
>  include/asm-x86_64/timex.h       |   30 +++
>  include/asm-x86_64/vsyscall.h    |   18 +-
>  11 files changed, 384 insertions(+), 124 deletions(-)
> 

> # This is a BitKeeper generated patch for the following project:
> # Project Name: Linux kernel tree
> # This patch format is intended for GNU patch command version 2.5 or higher.
> # This patch includes the following deltas:
> #	           ChangeSet	1.1436  -> 1.1440 
> #	arch/x86_64/vmlinux.lds.S	1.16    -> 1.17   
> #	arch/x86_64/kernel/apic.c	1.20    -> 1.21   
> #	include/asm-x86_64/fixmap.h	1.3     -> 1.4    
> #	arch/x86_64/kernel/acpi/boot.c	1.1     -> 1.2    
> #	include/asm-x86_64/mc146818rtc.h	1.1     -> 1.2    
> #	include/asm-x86_64/timex.h	1.6     -> 1.7    
> #	arch/x86_64/kernel/time.c	1.15    -> 1.18   
> #	arch/x86_64/kernel/vsyscall.c	1.10    -> 1.11   
> #	 arch/x86_64/Kconfig	1.22    -> 1.23   
> #	include/asm-x86_64/vsyscall.h	1.5     -> 1.6    
> #	arch/x86_64/kernel/smpboot.c	1.19    -> 1.20   
> #
> # The following is the BitKeeper ChangeSet Log
> # --------------------------------------------
> # 03/06/11	bos@serpentine.com	1.1437
> # Forward port 2.4 time code.  Optionally uses HPET instead of PIT/RTC for
> # gettimeofday calculations.  Far more stable than the current 2.5 code.
> # 
> # Current caveat: this code doesn't track lost interrupts properly, so we
> # can very slowly lose a jiffy here or there.
> # --------------------------------------------
> # 03/06/11	bos@serpentine.com	1.1438
> # Fix residual bogons.
> # 03/06/12	bos@serpentine.com	1.1440
> # Further fixes to 2.5 time code.
> # --------------------------------------------
> #
> diff -Nru a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
> --- a/arch/x86_64/Kconfig	Thu Jun 12 10:44:01 2003
> +++ b/arch/x86_64/Kconfig	Thu Jun 12 10:44:01 2003
> @@ -52,6 +52,18 @@
>  	  klogd/syslogd or the X server. You should normally N here, unless
>  	  you want to debug such a crash.
>  	  
> +config HPET_TIMER
> +	bool
> +	default y
> +	help
> +	  Use the IA-PC HPET (High Precision Event Timer) to manage
> +	  time in preference to the PIT and RTC, if a HPET is
> +	  present.  The HPET provides a stable time base on SMP
> +	  systems, unlike the RTC, but it is more expensive to access,
> +	  as it is off-chip.  You can find the HPET spec at
> +	  <http://www.intel.com/labs/platcomp/hpet/hpetspec.htm>.
> +
> +	  If unsure, say Y.
>  
>  config GENERIC_ISA_DMA
>  	bool
> diff -Nru a/arch/x86_64/kernel/acpi/boot.c b/arch/x86_64/kernel/acpi/boot.c
> --- a/arch/x86_64/kernel/acpi/boot.c	Thu Jun 12 10:44:01 2003
> +++ b/arch/x86_64/kernel/acpi/boot.c	Thu Jun 12 10:44:01 2003
> @@ -244,9 +244,11 @@
>  		return -1;
>  	}
>  
> -	hpet.address = hpet_tbl->addr.addrl | ((long) hpet_tbl->addr.addrh << 32);
> +	vxtime.hpet_address = hpet_tbl->addr.addrl |
> +		((long) hpet_tbl->addr.addrh << 32);
>  
> -	printk(KERN_INFO "acpi: HPET id: %#x base: %#lx\n", hpet_tbl->id, hpet.address);
> +	printk(KERN_INFO "acpi: HPET id: %#x base: %#lx\n",
> +	       hpet_tbl->id, vxtime.hpet_address);
>  
>  	return 0;
>  } 
> diff -Nru a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
> --- a/arch/x86_64/kernel/apic.c	Thu Jun 12 10:44:01 2003
> +++ b/arch/x86_64/kernel/apic.c	Thu Jun 12 10:44:01 2003
> @@ -46,7 +46,7 @@
>  void enable_NMI_through_LVT0 (void * dummy)
>  {
>  	unsigned int v, ver;
> -	
> +
>  	ver = apic_read(APIC_LVR);
>  	ver = GET_APIC_VERSION(ver);
>  	v = APIC_DM_NMI;                        /* unmask and set to NMI */
> @@ -297,7 +297,7 @@
>  	 * Double-check whether this APIC is really registered.
>  	 * This is meaningless in clustered apic mode, so we skip it.
>  	 */
> -	if (!clustered_apic_mode && 
> +	if (!clustered_apic_mode &&
>  	    !test_bit(GET_APIC_ID(apic_read(APIC_ID)), &phys_cpu_present_map))
>  		BUG();
>  
> @@ -309,7 +309,7 @@
>  
>  	if (!clustered_apic_mode) {
>  		/*
> -		 * In clustered apic mode, the firmware does this for us 
> +		 * In clustered apic mode, the firmware does this for us
>  		 * Put the APIC into flat delivery mode.
>  		 * Must be "all ones" explicitly for 82489DX.
>  		 */
> @@ -422,15 +422,15 @@
>  		value = apic_read(APIC_ESR);
>  		Dprintk("ESR value after enabling vector: %08x\n", value);
>  	} else {
> -		if (esr_disable)	
> -			/* 
> -			 * Something untraceble is creating bad interrupts on 
> +		if (esr_disable)
> +			/*
> +			 * Something untraceble is creating bad interrupts on
>  			 * secondary quads ... for the moment, just leave the
>  			 * ESR disabled - we can't do anything useful with the
>  			 * errors anyway - mbligh
>  			 */
>  			printk("Leaving ESR disabled.\n");
> -		else 
> +		else
>  			printk("No ESR for 82489DX.\n");
>  	}
>  
> @@ -580,7 +580,7 @@
>   * Detect and enable local APICs on non-SMP boards.
>   * Original code written by Keir Fraser.
>   * On AMD64 we trust the BIOS - if it says no APIC it is likely
> - * not correctly set up (usually the APIC timer won't work etc.) 
> + * not correctly set up (usually the APIC timer won't work etc.)
>   */
>  
>  static int __init detect_init_APIC (void)
> @@ -683,19 +683,25 @@
>  
>  	local_irq_save(flags);
>  
> -	/* For some reasons this doesn't work on Simics, so fake it for now */ 
> -	if (!strstr(boot_cpu_data.x86_model_id, "Screwdriver")) { 
> +	/* For some reasons this doesn't work on Simics, so fake it for now */
> +	if (!strstr(boot_cpu_data.x86_model_id, "Screwdriver")) {
>  	__setup_APIC_LVTT(clocks);
>  		return;
> -	} 
> +	}
>  
>  	/* wait for irq slice */
> -	{
> +	if (vxtime.hpet_address) {
> +		int trigger = hpet_readl(HPET_T0_CMP);
> +		while (hpet_readl(HPET_COUNTER) >= trigger)
> +			/* do nothing */ ;
> +		while (hpet_readl(HPET_COUNTER) <  trigger)
> +			/* do nothing */ ;
> +	} else {
>  		int c1, c2;
>  		outb_p(0x00, 0x43);
>  		c2 = inb_p(0x40);
>  		c2 |= inb_p(0x40) << 8;
> -	do {
> +		do {
>  			c1 = c2;
>  			outb_p(0x00, 0x43);
>  			c2 = inb_p(0x40);
> @@ -754,10 +760,10 @@
>  
>  void __init setup_boot_APIC_clock (void)
>  {
> -	if (disable_apic_timer) { 
> -		printk(KERN_INFO "Disabling APIC timer\n"); 
> -		return; 
> -	} 
> +	if (disable_apic_timer) {
> +		printk(KERN_INFO "Disabling APIC timer\n");
> +		return;
> +	}
>  
>  	printk(KERN_INFO "Using local APIC timer interrupts.\n");
>  	using_apic_timer = 1;
> @@ -816,7 +822,7 @@
>  	if ( (!multiplier) || (calibration_result/multiplier < 500))
>  		return -EINVAL;
>  
> -	/* 
> +	/*
>  	 * Set the new multiplier for each CPU. CPUs don't start using the
>  	 * new values until the next timer interrupt in which they do process
>  	 * accounting. At that time they also adjust their APIC timers
> @@ -856,7 +862,7 @@
>  		 * Interrupts are already masked off at this point.
>  		 */
>  		per_cpu(prof_counter, cpu) = per_cpu(prof_multiplier, cpu);
> -		if (per_cpu(prof_counter, cpu) != 
> +		if (per_cpu(prof_counter, cpu) !=
>  		    per_cpu(prof_old_multiplier, cpu)) {
>  			__setup_APIC_LVTT(calibration_result/
>  					per_cpu(prof_counter, cpu));
> @@ -928,19 +934,19 @@
>  		ack_APIC_irq();
>  
>  #if 0
> -	static unsigned long last_warning; 
> -	static unsigned long skipped; 
> +	static unsigned long last_warning;
> +	static unsigned long skipped;
>  
>  	/* see sw-dev-man vol 3, chapter 7.4.13.5 */
> -	if (time_before(last_warning+30*HZ,jiffies)) { 
> +	if (time_before(last_warning+30*HZ,jiffies)) {
>  		printk(KERN_INFO "spurious APIC interrupt on CPU#%d, %ld skipped.\n",
>  		       smp_processor_id(), skipped);
> -		last_warning = jiffies; 
> +		last_warning = jiffies;
>  		skipped = 0;
> -	} else { 
> -		skipped++; 
> -	} 
> -#endif 
> +	} else {
> +		skipped++;
> +	}
> +#endif
>  	irq_exit();
>  }
>  
> @@ -975,7 +981,7 @@
>  	irq_exit();
>  }
>  
> -int disable_apic; 
> +int disable_apic;
>  
>  /*
>   * This initializes the IO-APIC and APIC hardware if this is
> @@ -983,11 +989,11 @@
>   */
>  int __init APIC_init_uniprocessor (void)
>  {
> -	if (disable_apic) { 
> +	if (disable_apic) {
>  		printk(KERN_INFO "Apic disabled\n");
> -		return -1; 
> +		return -1;
>  	}
> -	if (!cpu_has_apic) { 
> +	if (!cpu_has_apic) {
>  		disable_apic = 1;
>  		printk(KERN_INFO "Apic disabled by BIOS\n");
>  		return -1;
> @@ -1015,18 +1021,18 @@
>  	return 0;
>  }
>  
> -static __init int setup_disableapic(char *str) 
> -{ 
> +static __init int setup_disableapic(char *str)
> +{
>  	disable_apic = 1;
>  	return 0;
> -} 
> +}
>  
> -static __init int setup_noapictimer(char *str) 
> -{ 
> +static __init int setup_noapictimer(char *str)
> +{
>  	disable_apic_timer = 1;
>  	return 0;
> -} 
> +}
>  
> -__setup("disableapic", setup_disableapic); 
> -__setup("noapictimer", setup_noapictimer); 
> +__setup("disableapic", setup_disableapic);
> +__setup("noapictimer", setup_noapictimer);
>  
> diff -Nru a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
> --- a/arch/x86_64/kernel/smpboot.c	Thu Jun 12 10:44:01 2003
> +++ b/arch/x86_64/kernel/smpboot.c	Thu Jun 12 10:44:01 2003
> @@ -67,6 +67,8 @@
>  /* Set when the idlers are all forked */
>  int smp_threads_ready;
>  
> +extern void time_init_smp(void);
> +
>  /*
>   * Trampoline 80x86 program as an array.
>   */
> @@ -760,7 +762,7 @@
>  		if (APIC_init_uniprocessor())
>  			printk(KERN_NOTICE "Local APIC not detected."
>  					   " Using dummy APIC emulation.\n");
> -		return;
> +		goto smp_done;
>  	}
>  
>  	/*
> @@ -784,7 +786,7 @@
>  		cpu_online_map = phys_cpu_present_map = 1;
>  		phys_cpu_present_map = 1;
>  		disable_apic = 1;
> -		return;
> +		goto smp_done;
>  	}
>  
>  	verify_local_APIC();
> @@ -799,7 +801,7 @@
>  		cpu_online_map = phys_cpu_present_map = 1;
>  		phys_cpu_present_map = 1;
>  		disable_apic = 1;
> -		return;
> +		goto smp_done;
>  	}
>  
>  	connect_bsp_APIC();
> @@ -883,6 +885,9 @@
>  	 */
>  	if (cpu_has_tsc && cpucount)
>  		synchronize_tsc_bp();
> +
> + smp_done:
> +	time_init_smp();
>  }
>  
>  /* These are wrappers to interface to the new boot process.  Someone
> diff -Nru a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
> --- a/arch/x86_64/kernel/time.c	Thu Jun 12 10:44:01 2003
> +++ b/arch/x86_64/kernel/time.c	Thu Jun 12 10:44:01 2003
> @@ -24,6 +24,7 @@
>  #include <linux/module.h>
>  #include <linux/device.h>
>  #include <linux/bcd.h>
> +#include <asm/pgtable.h>
>  #include <asm/vsyscall.h>
>  #include <asm/timex.h>
>  #ifdef CONFIG_X86_LOCAL_APIC
> @@ -35,41 +36,61 @@
>  extern int using_apic_timer;
>  
>  spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
> +spinlock_t i8253_lock = SPIN_LOCK_UNLOCKED;
>  
>  extern int using_apic_timer;
>  extern void smp_local_timer_interrupt(struct pt_regs * regs);
>  
> +#undef HPET_HACK_ENABLE_DANGEROUS
>  
> -unsigned int cpu_khz;					/* TSC clocks / usec, not used here */
> -unsigned long hpet_period;				/* fsecs / HPET clock */
> -unsigned long hpet_tick;				/* HPET clocks / interrupt */
> -int hpet_report_lost_ticks;				/* command line option */
>  
> -struct hpet_data __hpet __section_hpet;			/* address, quotient, trigger, hz */
> +unsigned int cpu_khz;				/* TSC clocks / usec, not used here */
> +unsigned long hpet_period;			/* fsecs / HPET clock */
> +unsigned long hpet_tick;			/* HPET clocks / interrupt */
> +unsigned long vxtime_hz = 1193182;
> +int report_lost_ticks;				/* command line option */
> +
> +struct vxtime_data __vxtime __section_vxtime;	/* for vsyscalls */
>  
>  volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
>  unsigned long __wall_jiffies __section_wall_jiffies = INITIAL_JIFFIES;
>  struct timespec __xtime __section_xtime;
>  struct timezone __sys_tz __section_sys_tz;
>  
> +static inline void rdtscll_sync(unsigned long *tsc)
> +{
> +#ifdef CONFIG_SMP
> +	sync_core();
> +#endif
> +	rdtscll(*tsc);
> +}
> +
>  /*
>   * 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 hpet.trigger wasn't updated yet.
> + * 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.
> -         */
> + */
>  
> -inline unsigned int do_gettimeoffset(void)
> +static inline unsigned int do_gettimeoffset_tsc(void)
>  {
>  	unsigned long t;
> -	sync_core();
> -	rdtscll(t);	
> -	return (t  - hpet.last_tsc) * (1000000L / HZ) / hpet.ticks + hpet.offset;
> +	unsigned long x;
> +	rdtscll_sync(&t);
> +	x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> 32;
> +	return x;
> +}
> +
> +static inline unsigned int do_gettimeoffset_hpet(void)
> +{
> +	return ((hpet_readl(HPET_COUNTER) - vxtime.last) * 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
> @@ -87,7 +108,8 @@
>  		sec = xtime.tv_sec;
>  		usec = xtime.tv_nsec / 1000;
>  
> -		t = (jiffies - wall_jiffies) * (1000000L / HZ) + do_gettimeoffset();
> +		t = (jiffies - wall_jiffies) * (1000000L / HZ) +
> +			do_gettimeoffset();
>  		usec += t;
>  
>  	} while (read_seqretry(&xtime_lock, seq));
> @@ -169,17 +191,17 @@
>  	real_seconds = nowtime % 60;
>  	real_minutes = nowtime / 60;
>  	if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
> -		real_minutes += 30;		/* correct for half hour time zone */
> +		real_minutes += 30;	/* correct for half hour time zone */
>  	real_minutes %= 60;
>  
>  	if (abs(real_minutes - cmos_minutes) < 30) {
> -			BIN_TO_BCD(real_seconds);
> -			BIN_TO_BCD(real_minutes);
> +		BIN_TO_BCD(real_seconds);
> +		BIN_TO_BCD(real_minutes);
>  		CMOS_WRITE(real_seconds, RTC_SECONDS);
>  		CMOS_WRITE(real_minutes, RTC_MINUTES);
>  	} else
> -		printk(KERN_WARNING "time.c: can't update CMOS clock from %d to %d\n",
> -		       cmos_minutes, real_minutes);
> +		printk(KERN_WARNING "time.c: can't update CMOS clock "
> +		       "from %d to %d\n", cmos_minutes, real_minutes);
>  
>  /*
>   * The following flags have to be released exactly in this order, otherwise the
> @@ -198,27 +220,65 @@
>  static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
>  {
>  	static unsigned long rtc_update = 0;
> +	unsigned long tsc, lost = 0;
> +	int delay, offset = 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
>   * on the other CPU, so we need a lock. We also need to lock the vsyscall
>   * variables, because both do_timer() and us change them -arca+vojtech
> -	 */
> + */
>  
>  	write_seqlock(&xtime_lock);
>  
> -	{
> -		unsigned long t;
> +	if (vxtime.hpet_address) {
> +		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);
>  
> -		sync_core();
> -		rdtscll(t);
> -		hpet.offset = (t  - hpet.last_tsc) * (1000000L / HZ) / hpet.ticks + hpet.offset - 1000000L / HZ;
> -		if (hpet.offset >= 1000000L / HZ)
> -			hpet.offset = 0;
> -		hpet.ticks = min_t(long, max_t(long, (t  - hpet.last_tsc) * (1000000L / HZ) / (1000000L / HZ - hpet.offset),
> -				cpu_khz * 1000/HZ * 15 / 16), cpu_khz * 1000/HZ * 16 / 15); 
> -		hpet.last_tsc = t;
> +	if (vxtime.mode == VXTIME_HPET) {
> +		if (offset - vxtime.last > hpet_tick) {
> +			lost = (offset - vxtime.last) / hpet_tick - 1;
> +		}
> +
> +		vxtime.last = offset;
> +	} else {
> +		offset = (((tsc - vxtime.last_tsc) *
> +			   vxtime.tsc_quot) >> 32) - tick_usec;
> +
> +		if (offset < 0)
> +			offset = 0;
> +
> +		if (offset > (USEC_PER_SEC / HZ)) {
> +			lost = offset / (USEC_PER_SEC / HZ);
> +			offset %= (USEC_PER_SEC / HZ);
> +		}
> +
> +		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) {
> +		if (report_lost_ticks)
> +			printk(KERN_WARNING "time.c: Lost %ld timer "
> +			       "tick(s)! (rip %016lx)\n",
> +			       (offset - vxtime.last) / hpet_tick - 1,
> +			       regs->rip);
> +		jiffies += lost;
>  	}
>  
>  /*
> @@ -244,16 +304,16 @@
>   * 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'tcare, as it'll be updated on the next turn, and the problem (time way
> + * 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 ((~time_status & STA_UNSYNC) && xtime.tv_sec > rtc_update &&
> -		abs(xtime.tv_nsec - 500000000) <= tick_nsec / 2) {
> +	    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;
> @@ -263,6 +323,7 @@
>  {
>  	unsigned int timeout, year, mon, day, hour, min, sec;
>  	unsigned char last, this;
> +	unsigned long flags;
>  
>  /*
>   * The Linux interpretation of the CMOS clock register contents: When the
> @@ -272,7 +333,7 @@
>   * standard 8.3 MHz ISA bus.
>   */
>  
> -	spin_lock(&rtc_lock); 
> +	spin_lock_irqsave(&rtc_lock, flags);
>  
>  	timeout = 1000000;
>  	last = this = 0;
> @@ -286,28 +347,28 @@
>  /*
>   * Here we are safe to assume the registers won't change for a whole second, so
>   * we just go ahead and read them.
> -	 */
> + */
>  
> -		sec = CMOS_READ(RTC_SECONDS);
> -		min = CMOS_READ(RTC_MINUTES);
> -		hour = CMOS_READ(RTC_HOURS);
> -		day = CMOS_READ(RTC_DAY_OF_MONTH);
> -		mon = CMOS_READ(RTC_MONTH);
> -		year = CMOS_READ(RTC_YEAR);
> +	sec = CMOS_READ(RTC_SECONDS);
> +	min = CMOS_READ(RTC_MINUTES);
> +	hour = CMOS_READ(RTC_HOURS);
> +	day = CMOS_READ(RTC_DAY_OF_MONTH);
> +	mon = CMOS_READ(RTC_MONTH);
> +	year = CMOS_READ(RTC_YEAR);
>  
> -	spin_unlock(&rtc_lock);
> +	spin_unlock_irqrestore(&rtc_lock, flags);
>  
>  /*
>   * We know that x86-64 always uses BCD format, no need to check the config
>   * register.
>   */
>  
> -	    BCD_TO_BIN(sec);
> -	    BCD_TO_BIN(min);
> -	    BCD_TO_BIN(hour);
> -	    BCD_TO_BIN(day);
> -	    BCD_TO_BIN(mon);
> -	    BCD_TO_BIN(year);
> +	BCD_TO_BIN(sec);
> +	BCD_TO_BIN(min);
> +	BCD_TO_BIN(hour);
> +	BCD_TO_BIN(day);
> +	BCD_TO_BIN(mon);
> +	BCD_TO_BIN(year);
>  
>  /*
>   * This will work up to Dec 31, 2069.
> @@ -326,6 +387,32 @@
>  
>  #define TICK_COUNT 100000000
>  
> +static unsigned int __init hpet_calibrate_tsc(void)
> +{
> +	int tsc_start, hpet_start;
> +	int tsc_now, hpet_now;
> +	unsigned long flags;
> +
> +	local_irq_save(flags);
> +	local_irq_disable();
> +
> +	hpet_start = hpet_readl(HPET_COUNTER);
> +	rdtscl(tsc_start);
> +
> +	do {
> +		local_irq_disable();
> +		hpet_now = hpet_readl(HPET_COUNTER);
> +		sync_core();
> +		rdtscl(tsc_now);
> +		local_irq_restore(flags);
> +	} while ((tsc_now - tsc_start) < TICK_COUNT &&
> +		 (hpet_now - hpet_start) < TICK_COUNT);
> +
> +	return (tsc_now - tsc_start) * 1000000000L
> +		/ ((hpet_now - hpet_start) * hpet_period / 1000);
> +}
> +
> +
>  /*
>   * pit_calibrate_tsc() uses the speaker output (channel 2) of
>   * the PIT. This is better than using the timer interrupt output,
> @@ -339,10 +426,9 @@
>  	unsigned long start, end;
>  	unsigned long flags;
>  
> -	outb((inb(0x61) & ~0x02) | 0x01, 0x61);
> +	spin_lock_irqsave(&i8253_lock, flags);
>  
> -	local_irq_save(flags);
> -	local_irq_disable();
> +	outb((inb(0x61) & ~0x02) | 0x01, 0x61);
>  
>  	outb(0xb0, 0x43);
>  	outb((1193182 / (1000 / 50)) & 0xff, 0x42);
> @@ -353,42 +439,146 @@
>  	sync_core();
>  	rdtscll(end);
>  
> +	spin_unlock_irqrestore(&i8253_lock, flags);
>  
> -	local_irq_restore(flags);
> -	
>  	return (end - start) / 50;
>  }
>  
> +static int hpet_init(void)
> +{
> +	unsigned int cfg, id;
> +
> +	if (!vxtime.hpet_address)
> +		return -1;
> +	set_fixmap_nocache(FIX_HPET_BASE, vxtime.hpet_address);
> +
> +/*
> + * Read the period, compute tick and quotient.
> + */
> +
> +	id = hpet_readl(HPET_ID);
> +
> +	if (!(id & HPET_ID_VENDOR) || !(id & HPET_ID_NUMBER) ||
> +	    !(id & HPET_ID_LEGSUP))
> +		return -1;
> +
> +	hpet_period = hpet_readl(HPET_PERIOD);
> +	if (hpet_period < 100000 || hpet_period > 100000000)
> +		return -1;
> +
> +	hpet_tick = (1000000000L * (USEC_PER_SEC / HZ) + hpet_period / 2) /
> +		hpet_period;
> +
> +/*
> + * Stop the timers and reset the main counter.
> + */
> +
> +	cfg = hpet_readl(HPET_CFG);
> +	cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY);
> +	hpet_writel(cfg, HPET_CFG);
> +	hpet_writel(0, HPET_COUNTER);
> +	hpet_writel(0, HPET_COUNTER + 4);
> +
> +/*
> + * Set up timer 0, as periodic with first interrupt to happen at hpet_tick,
> + * and period also hpet_tick.
> + */
> +
> +	hpet_writel(HPET_T0_ENABLE | HPET_T0_PERIODIC | HPET_T0_SETVAL |
> +		    HPET_T0_32BIT, HPET_T0_CFG);
> +	hpet_writel(hpet_tick, HPET_T0_CMP);
> +	hpet_writel(hpet_tick, HPET_T0_CMP);
> +
> +/*
> + * Go!
> + */
> +
> +	cfg |= HPET_CFG_ENABLE | HPET_CFG_LEGACY;
> +	hpet_writel(cfg, HPET_CFG);
> +
> +	return 0;
> +}
> +
>  void __init pit_init(void)
>  {
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&i8253_lock, flags);
>  	outb_p(0x34, 0x43);		/* binary, mode 2, LSB/MSB, ch 0 */
>  	outb_p(LATCH & 0xff, 0x40);	/* LSB */
>  	outb_p(LATCH >> 8, 0x40);	/* MSB */
> +	spin_unlock_irqrestore(&i8253_lock, flags);
>  }
>  
>  int __init time_setup(char *str)
>  {
> -	hpet_report_lost_ticks = 1;
> +	report_lost_ticks = 1;
>  	return 1;
>  }
>  
> -static struct irqaction irq0 = { timer_interrupt, SA_INTERRUPT, 0, "timer", NULL, NULL};
> +static struct irqaction irq0 = {
> +	timer_interrupt, SA_INTERRUPT, 0, "timer", NULL, NULL
> +};
>  
>  extern void __init config_acpi_tables(void);
>  
>  void __init time_init(void)
>  {
> +	char *timename;
> +
> +#ifdef HPET_HACK_ENABLE_DANGEROUS
> +        if (!vxtime.hpet_address) {
> +		printk(KERN_WARNING "time.c: WARNING: Enabling HPET base "
> +		       "manually!\n");
> +                outl(0x800038a0, 0xcf8);
> +                outl(0xff000001, 0xcfc);
> +                outl(0x800038a0, 0xcf8);
> +                hpet_address = inl(0xcfc) & 0xfffffffe;
> +		printk(KERN_WARNING "time.c: WARNING: Enabled HPET "
> +		       "at %#lx.\n", hpet_address);
> +        }
> +#endif
> +
>  	xtime.tv_sec = get_cmos_time();
>  	xtime.tv_nsec = 0;
>  
> -	pit_init();
> -	printk(KERN_INFO "time.c: Using 1.1931816 MHz PIT timer.\n");
> -	cpu_khz = pit_calibrate_tsc();
> +	if (!hpet_init()) {
> +                vxtime_hz = (1000000000000000L + hpet_period / 2) /
> +			hpet_period;
> +		cpu_khz = hpet_calibrate_tsc();
> +		timename = "HPET";
> +	} else {
> +		pit_init();
> +		cpu_khz = pit_calibrate_tsc();
> +		timename = "PIT";
> +	}
> +
> +	printk(KERN_INFO "time.c: Using %ld.%06ld MHz %s timer.\n",
> +	       vxtime_hz / 1000000, vxtime_hz % 1000000, timename);
>  	printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n",
>  		cpu_khz / 1000, cpu_khz % 1000);
> -	hpet.ticks = cpu_khz * (1000 / HZ);
> -	rdtscll(hpet.last_tsc);
> +	vxtime.mode = VXTIME_TSC;
> +	vxtime.quot = (1000000L << 32) / vxtime_hz;
> +	vxtime.tsc_quot = (1000L << 32) / cpu_khz;
> +	vxtime.hz = vxtime_hz;
> +	rdtscll_sync(&vxtime.last_tsc);
>  	setup_irq(0, &irq0);
> +}
> +
> +void __init time_init_smp(void)
> +{
> +	char *timetype;
> +
> +	if (vxtime.hpet_address) {
> +		timetype = "HPET";
> +		vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick;
> +		vxtime.mode = VXTIME_HPET;
> +		do_gettimeoffset = do_gettimeoffset_hpet;
> +	} else {
> +		timetype = "PIT/TSC";
> +		vxtime.mode = VXTIME_TSC;
> +	}
> +	printk(KERN_INFO "time.c: Using %s based timekeeping.\n", timetype);
>  }
>  
>  __setup("report_lost_ticks", time_setup);
> diff -Nru a/arch/x86_64/kernel/vsyscall.c b/arch/x86_64/kernel/vsyscall.c
> --- a/arch/x86_64/kernel/vsyscall.c	Thu Jun 12 10:44:01 2003
> +++ b/arch/x86_64/kernel/vsyscall.c	Thu Jun 12 10:44:01 2003
> @@ -33,7 +33,7 @@
>   *
>   * Add HPET support (port from 2.4). Still needed?
>   * Nop out vsyscall syscall to avoid anchor for buffer overflows when sysctl off.
> - * 
> + *
>   * These are not urgent things that we need to address only before shipping the first
>   * production binary kernels.
>   */
> @@ -77,14 +77,22 @@
>  
>  	do {
>  		sequence = read_seqbegin(&__xtime_lock);
> -		
> -		sync_core();
> -		rdtscll(t);
> +
>  		sec = __xtime.tv_sec;
>  		usec = (__xtime.tv_nsec / 1000) +
> -			(__jiffies - __wall_jiffies) * (1000000 / HZ) +
> -			(t  - __hpet.last_tsc) * (1000000 / HZ) / __hpet.ticks + __hpet.offset;
> +			(__jiffies - __wall_jiffies) * (1000000 / HZ);
>  
> +		if (__vxtime.mode == VXTIME_TSC) {
> +			sync_core();
> +			rdtscll(t);
> +			usec += ((t - __vxtime.last_tsc) *
> +				 __vxtime.tsc_quot) >> 32;
> +		} else {
> +#if 0
> +			usec += ((readl(fix_to_virt(VSYSCALL_HPET) + 0xf0) -
> +				  __vxtime.last) * __vxtime.quot) >> 32;
> +#endif
> +		}
>  	} while (read_seqretry(&__xtime_lock, sequence));
>  
>  	tv->tv_sec = sec + usec / 1000000;
> @@ -100,7 +108,7 @@
>  static force_inline int gettimeofday(struct timeval *tv, struct timezone *tz)
>  {
>  	int ret;
> -	asm volatile("syscall" 
> +	asm volatile("syscall"
>  		: "=a" (ret)
>  		: "0" (__NR_gettimeofday),"D" (tv),"S" (tz) : __syscall_clobber );
>  	return ret;
> @@ -109,7 +117,7 @@
>  static int __vsyscall(0) vgettimeofday(struct timeval * tv, struct timezone * tz)
>  {
>  	if (unlikely(!__sysctl_vsyscall))
> -	return gettimeofday(tv,tz); 
> +	return gettimeofday(tv,tz);
>  	if (tv)
>  		do_vgettimeofday(tv);
>  	if (tz)
> @@ -119,13 +127,13 @@
>  
>  static time_t __vsyscall(1) vtime(time_t * t)
>  {
> -	struct timeval tv; 
> +	struct timeval tv;
>  	if (unlikely(!__sysctl_vsyscall))
>  		gettimeofday(&tv, NULL);
>  	else
>  		do_vgettimeofday(&tv);
>  	if (t)
> -		*t = tv.tv_sec; 
> +		*t = tv.tv_sec;
>  	return tv.tv_sec;
>  }
>  
> diff -Nru a/arch/x86_64/vmlinux.lds.S b/arch/x86_64/vmlinux.lds.S
> --- a/arch/x86_64/vmlinux.lds.S	Thu Jun 12 10:44:01 2003
> +++ b/arch/x86_64/vmlinux.lds.S	Thu Jun 12 10:44:01 2003
> @@ -50,10 +50,10 @@
>    .xtime_lock : AT ((LOADADDR(.vsyscall_0) + SIZEOF(.vsyscall_0) + 63) & ~(63)) { *(.xtime_lock) }
>    xtime_lock = LOADADDR(.xtime_lock);
>    . = ALIGN(16);
> -  .hpet : AT ((LOADADDR(.xtime_lock) + SIZEOF(.xtime_lock) + 15) & ~(15)) { *(.hpet) }
> -  hpet = LOADADDR(.hpet);
> +  .vxtime : AT ((LOADADDR(.xtime_lock) + SIZEOF(.xtime_lock) + 15) & ~(15)) { *(.vxtime) }
> +  vxtime = LOADADDR(.vxtime);
>    . = ALIGN(16);
> -  .wall_jiffies : AT ((LOADADDR(.hpet) + SIZEOF(.hpet) + 15) & ~(15)) { *(.wall_jiffies) }
> +  .wall_jiffies : AT ((LOADADDR(.vxtime) + SIZEOF(.vxtime) + 15) & ~(15)) { *(.wall_jiffies) }
>    wall_jiffies = LOADADDR(.wall_jiffies);
>    . = ALIGN(16);
>    .sys_tz : AT ((LOADADDR(.wall_jiffies) + SIZEOF(.wall_jiffies) + 15) & ~(15)) { *(.sys_tz) }
> diff -Nru a/include/asm-x86_64/fixmap.h b/include/asm-x86_64/fixmap.h
> --- a/include/asm-x86_64/fixmap.h	Thu Jun 12 10:44:01 2003
> +++ b/include/asm-x86_64/fixmap.h	Thu Jun 12 10:44:01 2003
> @@ -35,6 +35,8 @@
>  enum fixed_addresses {
>  	VSYSCALL_LAST_PAGE,
>  	VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
> +	VSYSCALL_HPET,
> +	FIX_HPET_BASE,
>  #ifdef CONFIG_X86_LOCAL_APIC
>  	FIX_APIC_BASE,	/* local (CPU) APIC) -- required for SMP or not */
>  #endif
> diff -Nru a/include/asm-x86_64/mc146818rtc.h b/include/asm-x86_64/mc146818rtc.h
> --- a/include/asm-x86_64/mc146818rtc.h	Thu Jun 12 10:44:01 2003
> +++ b/include/asm-x86_64/mc146818rtc.h	Thu Jun 12 10:44:01 2003
> @@ -24,6 +24,11 @@
>  outb_p((val),RTC_PORT(1)); \
>  })
>  
> +#ifndef CONFIG_HPET_TIMER
>  #define RTC_IRQ 8
> +#else
> +/* Temporary workaround due to IRQ routing problem. */
> +#define RTC_IRQ 0
> +#endif
>  
>  #endif /* _ASM_MC146818RTC_H */
> diff -Nru a/include/asm-x86_64/timex.h b/include/asm-x86_64/timex.h
> --- a/include/asm-x86_64/timex.h	Thu Jun 12 10:44:01 2003
> +++ b/include/asm-x86_64/timex.h	Thu Jun 12 10:44:01 2003
> @@ -30,6 +30,34 @@
>  
>  extern unsigned int cpu_khz;
>  
> -extern struct hpet_data hpet;
> +/*
> + * Documentation on HPET can be found at:
> + *      http://www.intel.com/ial/home/sp/pcmmspec.htm
> + *      ftp://download.intel.com/ial/home/sp/mmts098.pdf
> + */
> +
> +#define HPET_ID		0x000
> +#define HPET_PERIOD	0x004
> +#define HPET_CFG	0x010
> +#define HPET_STATUS	0x020
> +#define HPET_COUNTER	0x0f0
> +#define HPET_T0_CFG	0x100
> +#define HPET_T0_CMP	0x108
> +#define HPET_T0_ROUTE	0x110
> +
> +#define HPET_ID_VENDOR	0xffff0000
> +#define HPET_ID_LEGSUP	0x00008000
> +#define HPET_ID_NUMBER	0x00000f00
> +#define HPET_ID_REV	0x000000ff
> +
> +#define HPET_CFG_ENABLE	0x001
> +#define HPET_CFG_LEGACY	0x002
> +
> +#define HPET_T0_ENABLE		0x004
> +#define HPET_T0_PERIODIC	0x008
> +#define HPET_T0_SETVAL		0x040
> +#define HPET_T0_32BIT		0x100
> +
> +extern struct vxtime_data vxtime;
>  
>  #endif
> diff -Nru a/include/asm-x86_64/vsyscall.h b/include/asm-x86_64/vsyscall.h
> --- a/include/asm-x86_64/vsyscall.h	Thu Jun 12 10:44:01 2003
> +++ b/include/asm-x86_64/vsyscall.h	Thu Jun 12 10:44:01 2003
> @@ -15,7 +15,7 @@
>  
>  #ifdef __KERNEL__
>  
> -#define __section_hpet __attribute__ ((unused, __section__ (".hpet"), aligned(16)))
> +#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)))
>  #define __section_sys_tz __attribute__ ((unused, __section__ (".sys_tz"), aligned(16)))
> @@ -23,22 +23,24 @@
>  #define __section_xtime __attribute__ ((unused, __section__ (".xtime"), aligned(16)))
>  #define __section_xtime_lock __attribute__ ((unused, __section__ (".xtime_lock"), aligned(L1_CACHE_BYTES)))
>  
> +#define VXTIME_TSC	1
> +#define VXTIME_HPET	2
>  
> -struct hpet_data {
> -	long address;		/* base address */
> +struct vxtime_data {
> +	long hpet_address;	/* HPET base address */
>  	unsigned long hz;	/* HPET clocks / sec */
> -	int trigger;		/* value at last interrupt */
>  	int last;
> -	int offset;
>  	unsigned long last_tsc;
> -	long ticks;
> +	long quot;
> +	long tsc_quot;
> +	int mode;
>  };
>  
>  #define hpet_readl(a)           readl(fix_to_virt(FIX_HPET_BASE) + a)
>  #define hpet_writel(d,a)        writel(d, fix_to_virt(FIX_HPET_BASE) + a)
>  
>  /* vsyscall space (readonly) */
> -extern struct hpet_data __hpet;
> +extern struct vxtime_data __vxtime;
>  extern struct timespec __xtime;
>  extern volatile unsigned long __jiffies;
>  extern unsigned long __wall_jiffies;
> @@ -46,7 +48,7 @@
>  extern seqlock_t __xtime_lock;
>  
>  /* kernel space (writeable) */
> -extern struct hpet_data hpet;
> +extern struct vxtime_data vxtime;
>  extern unsigned long wall_jiffies;
>  extern struct timezone sys_tz;
>  extern int sysctl_vsyscall;


-- 
Vojtech Pavlik
SuSE Labs, SuSE CR