[PATCH] Time changes for x86-64

Some timer updates from Vojtech Pavlik for x86-64.  In theory support
HPET timing now, but the support is disabled.

Would actually need vxtime_lock() macros in the generic timer code to
protect xtime updates, but I'm leaving that out now because it's only
needed for vsyscalls and they're currently disabled.

arch/x86_64/kernel/vsyscall.c

@@ -47,7 +47,7 @@
 
 #define __vsyscall(nr) __attribute__ ((unused,__section__(".vsyscall_" #nr)))
 
-//#define NO_VSYSCALL 1
+#define NO_VSYSCALL 1
 
 #ifdef NO_VSYSCALL
 #include <asm/unistd.h>
@@ -71,51 +71,27 @@ static inline void timeval_normalize(struct timeval * tv)
 
 long __vxtime_sequence[2] __section_vxtime_sequence;
 
+
 static inline void do_vgettimeofday(struct timeval * tv)
 {
-	long sequence;
-	unsigned long usec, sec;
+	long sequence, t;
+	unsigned long sec, usec;
 
 	do {
-		unsigned long eax, edx;
-
 		sequence = __vxtime_sequence[1];
 		rmb();
 		
-		/* Read the Time Stamp Counter */
-		rdtsc(eax,edx);
-
-		/* .. relative to previous jiffy (32 bits is enough) */
-		eax -= __last_tsc_low;	/* tsc_low delta */
-
-		/*
-		 * Time offset = (tsc_low delta) * fast_gettimeoffset_quotient
-		 *             = (tsc_low delta) * (usecs_per_clock)
-		 *             = (tsc_low delta) * (usecs_per_jiffy / clocks_per_jiffy)
-		 *
-		 * Using a mull instead of a divl saves up to 31 clock cycles
-		 * in the critical path.
-		 */
-
-		edx = (eax*__fast_gettimeoffset_quotient) >> 32;
-
-		/* our adjusted time offset in microseconds */
-		usec = __delay_at_last_interrupt + edx;
-
-		{
-			unsigned long lost = __jiffies - __wall_jiffies;
-			if (lost)
-				usec += lost * (1000000 / HZ);
-		}
+		rdtscll(t);
 		sec = __xtime.tv_sec;
-		usec += __xtime.tv_usec;
+		usec = __xtime.tv_usec +
+			(__jiffies - __wall_jiffies) * (1000000 / HZ) +
+			(t  - __hpet.last_tsc) * (1000000 / HZ) / __hpet.ticks + __hpet.offset;
 
 		rmb();
 	} while (sequence != __vxtime_sequence[0]);
 
-	tv->tv_sec = sec;
-	tv->tv_usec = usec;
-	timeval_normalize(tv);
+	tv->tv_sec = sec + usec / 1000000;
+	tv->tv_usec = usec % 1000000;
 }
 
 static inline void do_get_tz(struct timezone * tz)

include/asm-x86_64/timex.h

@@ -36,16 +36,14 @@ extern cycles_t cacheflush_time;
 
 static inline cycles_t get_cycles (void)
 {
-#ifndef CONFIG_X86_TSC
-	return 0;
-#else
 	unsigned long long ret;
 
 	rdtscll(ret);
 	return ret;
-#endif
 }
 
 extern unsigned int cpu_khz;
 
+extern struct hpet_data hpet;
+
 #endif

include/asm-x86_64/vsyscall.h

 #ifndef _ASM_X86_64_VSYSCALL_H_
 #define _ASM_X86_64_VSYSCALL_H_
 
+#include <linux/time.h>
+
 enum vsyscall_num {
 	__NR_vgettimeofday,
 	__NR_vtime,
@@ -13,32 +15,39 @@ enum vsyscall_num {
 
 #ifdef __KERNEL__
 
-#define __section_last_tsc_low	__attribute__ ((unused, __section__ (".last_tsc_low")))
-#define __section_delay_at_last_interrupt	__attribute__ ((unused, __section__ (".delay_at_last_interrupt")))
-#define __section_fast_gettimeoffset_quotient	__attribute__ ((unused, __section__ (".fast_gettimeoffset_quotient")))
-#define __section_wall_jiffies __attribute__ ((unused, __section__ (".wall_jiffies")))
-#define __section_jiffies __attribute__ ((unused, __section__ (".jiffies")))
-#define __section_sys_tz __attribute__ ((unused, __section__ (".sys_tz")))
-#define __section_xtime __attribute__ ((unused, __section__ (".xtime")))
-#define __section_vxtime_sequence __attribute__ ((unused, __section__ (".vxtime_sequence")))
+#define __section_hpet __attribute__ ((unused, __section__ (".hpet"), 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)))
+#define __section_xtime __attribute__ ((unused, __section__ (".xtime"), aligned(16)))
+#define __section_vxtime_sequence __attribute__ ((unused, __section__ (".vxtime_sequence"), aligned(16)))
+
+struct hpet_data {
+	long address;		/* base address */
+	unsigned long hz;	/* HPET clocks / sec */
+	int trigger;		/* value at last interrupt */
+	int last;
+	int offset;
+	unsigned long last_tsc;
+	long ticks;
+};
+
+#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 long __vxtime_sequence[2];
-extern int __delay_at_last_interrupt;
-extern unsigned int __last_tsc_low;
-extern unsigned int __fast_gettimeoffset_quotient;
-extern struct timeval __xtime;
+extern struct hpet_data __hpet;
+extern struct timespec __xtime;
 extern volatile unsigned long __jiffies;
 extern unsigned long __wall_jiffies;
 extern struct timezone __sys_tz;
 
 /* kernel space (writeable) */
-extern unsigned long last_tsc_low;
-extern int delay_at_last_interrupt;
-extern unsigned int fast_gettimeoffset_quotient;
+extern long vxtime_sequence[2];
+extern struct hpet_data hpet;
 extern unsigned long wall_jiffies;
 extern struct timezone sys_tz;
-extern long vxtime_sequence[2];
 
 #define vxtime_lock() do { vxtime_sequence[0]++; wmb(); } while(0)
 #define vxtime_unlock() do { wmb(); vxtime_sequence[1]++; } while (0)