Merge branches 'x86/mmio', 'x86/delay', 'x86/idle', 'x86/oprofile', 'x86/debug',...

[linux-2.6-omap-h63xx.git] / arch / x86 / kernel / tsc_32.c

diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c
index 068759db63ddebca0ed5561a1306a302dc38f474..6240922e497c30aa9a96a1982fe73a2a698ed5eb 100644 (file)
--- a/arch/x86/kernel/tsc_32.c
+++ b/arch/x86/kernel/tsc_32.c
@@ -1,6 +1,7 @@
 #include <linux/sched.h>
 #include <linux/clocksource.h>
 #include <linux/workqueue.h>
+#include <linux/delay.h>
 #include <linux/cpufreq.h>
 #include <linux/jiffies.h>
 #include <linux/init.h>
@@ -14,7 +15,10 @@
 
 #include "mach_timer.h"
 
-static int tsc_disabled;
+/* native_sched_clock() is called before tsc_init(), so
+   we must start with the TSC soft disabled to prevent
+   erroneous rdtsc usage on !cpu_has_tsc processors */
+static int tsc_disabled = -1;
 
 /*
  * On some systems the TSC frequency does not
@@ -283,7 +287,6 @@ core_initcall(cpufreq_tsc);
 
 /* clock source code */
 
-static unsigned long current_tsc_khz;
 static struct clocksource clocksource_tsc;
 
 /*
@@ -401,26 +404,26 @@ static inline void check_geode_tsc_reliable(void) { }
 void __init tsc_init(void)
 {
        int cpu;
+       u64 lpj;
 
-       if (!cpu_has_tsc || tsc_disabled) {
-               /* Disable the TSC in case of !cpu_has_tsc */
-               tsc_disabled = 1;
+       if (!cpu_has_tsc || tsc_disabled > 0)
                return;
-       }
 
        cpu_khz = calculate_cpu_khz();
        tsc_khz = cpu_khz;
 
        if (!cpu_khz) {
                mark_tsc_unstable("could not calculate TSC khz");
-               /*
-                * We need to disable the TSC completely in this case
-                * to prevent sched_clock() from using it.
-                */
-               tsc_disabled = 1;
                return;
        }
 
+       lpj = ((u64)tsc_khz * 1000);
+       do_div(lpj, HZ);
+       lpj_fine = lpj;
+
+       /* now allow native_sched_clock() to use rdtsc */
+       tsc_disabled = 0;
+
        printk("Detected %lu.%03lu MHz processor.\n",
                                (unsigned long)cpu_khz / 1000,
                                (unsigned long)cpu_khz % 1000);
@@ -441,9 +444,8 @@ void __init tsc_init(void)
 
        unsynchronized_tsc();
        check_geode_tsc_reliable();
-       current_tsc_khz = tsc_khz;
-       clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
-                                                       clocksource_tsc.shift);
+       clocksource_tsc.mult = clocksource_khz2mult(tsc_khz,
+                                                   clocksource_tsc.shift);
        /* lower the rating if we already know its unstable: */
        if (check_tsc_unstable()) {
                clocksource_tsc.rating = 0;