Merge commit 'v2.6.26-rc8' into x86/xen
[linux-3.10.git] / arch / x86 / xen / time.c
index b3721fd..64f0038 100644 (file)
@@ -12,7 +12,9 @@
 #include <linux/clocksource.h>
 #include <linux/clockchips.h>
 #include <linux/kernel_stat.h>
+#include <linux/math64.h>
 
+#include <asm/pvclock.h>
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
 
 
 static cycle_t xen_clocksource_read(void);
 
-/* These are perodically updated in shared_info, and then copied here. */
-struct shadow_time_info {
-       u64 tsc_timestamp;     /* TSC at last update of time vals.  */
-       u64 system_timestamp;  /* Time, in nanosecs, since boot.    */
-       u32 tsc_to_nsec_mul;
-       int tsc_shift;
-       u32 version;
-};
-
-static DEFINE_PER_CPU(struct shadow_time_info, shadow_time);
-
 /* runstate info updated by Xen */
 static DEFINE_PER_CPU(struct vcpu_runstate_info, runstate);
 
@@ -150,11 +141,7 @@ static void do_stolen_accounting(void)
        if (stolen < 0)
                stolen = 0;
 
-       ticks = 0;
-       while (stolen >= NS_PER_TICK) {
-               ticks++;
-               stolen -= NS_PER_TICK;
-       }
+       ticks = iter_div_u64_rem(stolen, NS_PER_TICK, &stolen);
        __get_cpu_var(residual_stolen) = stolen;
        account_steal_time(NULL, ticks);
 
@@ -166,11 +153,7 @@ static void do_stolen_accounting(void)
        if (blocked < 0)
                blocked = 0;
 
-       ticks = 0;
-       while (blocked >= NS_PER_TICK) {
-               ticks++;
-               blocked -= NS_PER_TICK;
-       }
+       ticks = iter_div_u64_rem(blocked, NS_PER_TICK, &blocked);
        __get_cpu_var(residual_blocked) = blocked;
        account_steal_time(idle_task(smp_processor_id()), ticks);
 }
@@ -217,134 +200,39 @@ unsigned long long xen_sched_clock(void)
 /* Get the CPU speed from Xen */
 unsigned long xen_cpu_khz(void)
 {
-       u64 cpu_khz = 1000000ULL << 32;
-       const struct vcpu_time_info *info =
+       u64 xen_khz = 1000000ULL << 32;
+       const struct pvclock_vcpu_time_info *info =
                &HYPERVISOR_shared_info->vcpu_info[0].time;
 
-       do_div(cpu_khz, info->tsc_to_system_mul);
+       do_div(xen_khz, info->tsc_to_system_mul);
        if (info->tsc_shift < 0)
-               cpu_khz <<= -info->tsc_shift;
-       else
-               cpu_khz >>= info->tsc_shift;
-
-       return cpu_khz;
-}
-
-/*
- * Reads a consistent set of time-base values from Xen, into a shadow data
- * area.
- */
-static unsigned get_time_values_from_xen(void)
-{
-       struct vcpu_time_info   *src;
-       struct shadow_time_info *dst;
-
-       /* src is shared memory with the hypervisor, so we need to
-          make sure we get a consistent snapshot, even in the face of
-          being preempted. */
-       src = &__get_cpu_var(xen_vcpu)->time;
-       dst = &__get_cpu_var(shadow_time);
-
-       do {
-               dst->version = src->version;
-               rmb();          /* fetch version before data */
-               dst->tsc_timestamp     = src->tsc_timestamp;
-               dst->system_timestamp  = src->system_time;
-               dst->tsc_to_nsec_mul   = src->tsc_to_system_mul;
-               dst->tsc_shift         = src->tsc_shift;
-               rmb();          /* test version after fetching data */
-       } while ((src->version & 1) | (dst->version ^ src->version));
-
-       return dst->version;
-}
-
-/*
- * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
- * yielding a 64-bit result.
- */
-static inline u64 scale_delta(u64 delta, u32 mul_frac, int shift)
-{
-       u64 product;
-#ifdef __i386__
-       u32 tmp1, tmp2;
-#endif
-
-       if (shift < 0)
-               delta >>= -shift;
+               xen_khz <<= -info->tsc_shift;
        else
-               delta <<= shift;
-
-#ifdef __i386__
-       __asm__ (
-               "mul  %5       ; "
-               "mov  %4,%%eax ; "
-               "mov  %%edx,%4 ; "
-               "mul  %5       ; "
-               "xor  %5,%5    ; "
-               "add  %4,%%eax ; "
-               "adc  %5,%%edx ; "
-               : "=A" (product), "=r" (tmp1), "=r" (tmp2)
-               : "a" ((u32)delta), "1" ((u32)(delta >> 32)), "2" (mul_frac) );
-#elif __x86_64__
-       __asm__ (
-               "mul %%rdx ; shrd $32,%%rdx,%%rax"
-               : "=a" (product) : "0" (delta), "d" ((u64)mul_frac) );
-#else
-#error implement me!
-#endif
-
-       return product;
-}
+               xen_khz >>= info->tsc_shift;
 
-static u64 get_nsec_offset(struct shadow_time_info *shadow)
-{
-       u64 now, delta;
-       now = native_read_tsc();
-       delta = now - shadow->tsc_timestamp;
-       return scale_delta(delta, shadow->tsc_to_nsec_mul, shadow->tsc_shift);
+       return xen_khz;
 }
 
 static cycle_t xen_clocksource_read(void)
 {
-       struct shadow_time_info *shadow = &get_cpu_var(shadow_time);
+        struct pvclock_vcpu_time_info *src;
        cycle_t ret;
-       unsigned version;
-
-       do {
-               version = get_time_values_from_xen();
-               barrier();
-               ret = shadow->system_timestamp + get_nsec_offset(shadow);
-               barrier();
-       } while (version != __get_cpu_var(xen_vcpu)->time.version);
-
-       put_cpu_var(shadow_time);
 
+       src = &get_cpu_var(xen_vcpu)->time;
+       ret = pvclock_clocksource_read(src);
+       put_cpu_var(xen_vcpu);
        return ret;
 }
 
 static void xen_read_wallclock(struct timespec *ts)
 {
-       const struct shared_info *s = HYPERVISOR_shared_info;
-       u32 version;
-       u64 delta;
-       struct timespec now;
-
-       /* get wallclock at system boot */
-       do {
-               version = s->wc_version;
-               rmb();          /* fetch version before time */
-               now.tv_sec  = s->wc_sec;
-               now.tv_nsec = s->wc_nsec;
-               rmb();          /* fetch time before checking version */
-       } while ((s->wc_version & 1) | (version ^ s->wc_version));
-
-       delta = xen_clocksource_read(); /* time since system boot */
-       delta += now.tv_sec * (u64)NSEC_PER_SEC + now.tv_nsec;
-
-       now.tv_nsec = do_div(delta, NSEC_PER_SEC);
-       now.tv_sec = delta;
+       struct shared_info *s = HYPERVISOR_shared_info;
+       struct pvclock_wall_clock *wall_clock = &(s->wc);
+        struct pvclock_vcpu_time_info *vcpu_time;
 
-       set_normalized_timespec(ts, now.tv_sec, now.tv_nsec);
+       vcpu_time = &get_cpu_var(xen_vcpu)->time;
+       pvclock_read_wallclock(wall_clock, vcpu_time, ts);
+       put_cpu_var(xen_vcpu);
 }
 
 unsigned long xen_get_wallclock(void)
@@ -352,7 +240,6 @@ unsigned long xen_get_wallclock(void)
        struct timespec ts;
 
        xen_read_wallclock(&ts);
-
        return ts.tv_sec;
 }
 
@@ -572,12 +459,23 @@ void xen_setup_cpu_clockevents(void)
        clockevents_register_device(&__get_cpu_var(xen_clock_events));
 }
 
+void xen_timer_resume(void)
+{
+       int cpu;
+
+       if (xen_clockevent != &xen_vcpuop_clockevent)
+               return;
+
+       for_each_online_cpu(cpu) {
+               if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL))
+                       BUG();
+       }
+}
+
 __init void xen_time_init(void)
 {
        int cpu = smp_processor_id();
 
-       get_time_values_from_xen();
-
        clocksource_register(&xen_clocksource);
 
        if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, cpu, NULL) == 0) {