Merge tag 'sunxi-fixes-for-4.3' of https://git.kernel.org/pub/scm/linux/kernel/git...

[linux-drm-fsl-dcu.git] / arch / x86 / kernel / tsc.c

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 7437b41f6a47c290e0f26b8933b45e469235ccc4..c3f7602cd0386b2fb0a1a7437263f9c71f27d03c 100644 (file)
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -21,6 +21,7 @@
 #include <asm/hypervisor.h>
 #include <asm/nmi.h>
 #include <asm/x86_init.h>
+#include <asm/geode.h>
 
 unsigned int __read_mostly cpu_khz;    /* TSC clocks / usec, not used here */
 EXPORT_SYMBOL(cpu_khz);
@@ -38,7 +39,7 @@ static int __read_mostly tsc_unstable;
    erroneous rdtsc usage on !cpu_has_tsc processors */
 static int __read_mostly tsc_disabled = -1;
 
-static struct static_key __use_tsc = STATIC_KEY_INIT;
+static DEFINE_STATIC_KEY_FALSE(__use_tsc);
 
 int tsc_clocksource_reliable;
 
@@ -248,7 +249,7 @@ static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
 
        data = cyc2ns_write_begin(cpu);
 
-       rdtscll(tsc_now);
+       tsc_now = rdtsc();
        ns_now = cycles_2_ns(tsc_now);
 
        /*
@@ -274,7 +275,12 @@ done:
  */
 u64 native_sched_clock(void)
 {
-       u64 tsc_now;
+       if (static_branch_likely(&__use_tsc)) {
+               u64 tsc_now = rdtsc();
+
+               /* return the value in ns */
+               return cycles_2_ns(tsc_now);
+       }
 
        /*
         * Fall back to jiffies if there's no TSC available:
@@ -284,16 +290,17 @@ u64 native_sched_clock(void)
         *   very important for it to be as fast as the platform
         *   can achieve it. )
         */
-       if (!static_key_false(&__use_tsc)) {
-               /* No locking but a rare wrong value is not a big deal: */
-               return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
-       }
 
-       /* read the Time Stamp Counter: */
-       rdtscll(tsc_now);
+       /* No locking but a rare wrong value is not a big deal: */
+       return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
+}
 
-       /* return the value in ns */
-       return cycles_2_ns(tsc_now);
+/*
+ * Generate a sched_clock if you already have a TSC value.
+ */
+u64 native_sched_clock_from_tsc(u64 tsc)
+{
+       return cycles_2_ns(tsc);
 }
 
 /* We need to define a real function for sched_clock, to override the
@@ -308,12 +315,6 @@ unsigned long long
 sched_clock(void) __attribute__((alias("native_sched_clock")));
 #endif
 
-unsigned long long native_read_tsc(void)
-{
-       return __native_read_tsc();
-}
-EXPORT_SYMBOL(native_read_tsc);
-
 int check_tsc_unstable(void)
 {
        return tsc_unstable;
@@ -976,7 +977,7 @@ static struct clocksource clocksource_tsc;
  */
 static cycle_t read_tsc(struct clocksource *cs)
 {
-       return (cycle_t)get_cycles();
+       return (cycle_t)rdtsc_ordered();
 }
 
 /*
@@ -1013,15 +1014,17 @@ EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
 static void __init check_system_tsc_reliable(void)
 {
-#ifdef CONFIG_MGEODE_LX
-       /* RTSC counts during suspend */
+#if defined(CONFIG_MGEODEGX1) || defined(CONFIG_MGEODE_LX) || defined(CONFIG_X86_GENERIC)
+       if (is_geode_lx()) {
+               /* RTSC counts during suspend */
 #define RTSC_SUSP 0x100
-       unsigned long res_low, res_high;
+               unsigned long res_low, res_high;
 
-       rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high);
-       /* Geode_LX - the OLPC CPU has a very reliable TSC */
-       if (res_low & RTSC_SUSP)
-               tsc_clocksource_reliable = 1;
+               rdmsr_safe(MSR_GEODE_BUSCONT_CONF0, &res_low, &res_high);
+               /* Geode_LX - the OLPC CPU has a very reliable TSC */
+               if (res_low & RTSC_SUSP)
+                       tsc_clocksource_reliable = 1;
+       }
 #endif
        if (boot_cpu_has(X86_FEATURE_TSC_RELIABLE))
                tsc_clocksource_reliable = 1;
@@ -1210,7 +1213,7 @@ void __init tsc_init(void)
        /* now allow native_sched_clock() to use rdtsc */
 
        tsc_disabled = 0;
-       static_key_slow_inc(&__use_tsc);
+       static_branch_enable(&__use_tsc);
 
        if (!no_sched_irq_time)
                enable_sched_clock_irqtime();