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authorThomas Gleixner <tglx@linutronix.de>2008-05-13 12:31:00 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 14:08:06 +0200
commit9ccc906c97e34fd91dc6aaf5b69b52d824386910 (patch)
treef494f852fbbc4aef95ab92ca45dfdd14c819fc72 /arch/x86/kernel/tsc_32.c
parentb6db80ee1331e7beaeb91b4b3d946dd16c72e388 (diff)
x86: distangle user disabled TSC from unstable
tsc_enabled is set to 0 from the command line switch "notsc" and from the mark_tsc_unstable code. Seperate those functionalities and replace tsc_enable with tsc_disable. This makes also the native_sched_clock() decision when to use TSC understandable. Preparatory patch to solve the sched_clock() issue on 32 bit. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/tsc_32.c')
-rw-r--r--arch/x86/kernel/tsc_32.c20
1 files changed, 10 insertions, 10 deletions
diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c
index e4790728b224..b087d691f165 100644
--- a/arch/x86/kernel/tsc_32.c
+++ b/arch/x86/kernel/tsc_32.c
@@ -14,7 +14,7 @@
#include "mach_timer.h"
-static int tsc_enabled;
+static int tsc_disabled;
/*
* On some systems the TSC frequency does not
@@ -28,8 +28,8 @@ EXPORT_SYMBOL_GPL(tsc_khz);
static int __init tsc_setup(char *str)
{
printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, "
- "cannot disable TSC completely.\n");
- mark_tsc_unstable("user disabled TSC");
+ "cannot disable TSC completely.\n");
+ tsc_disabled = 1;
return 1;
}
#else
@@ -120,7 +120,7 @@ unsigned long long native_sched_clock(void)
* very important for it to be as fast as the platform
* can achive it. )
*/
- if (unlikely(!tsc_enabled && !tsc_unstable))
+ if (unlikely(tsc_disabled))
/* No locking but a rare wrong value is not a big deal: */
return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
@@ -322,7 +322,6 @@ void mark_tsc_unstable(char *reason)
{
if (!tsc_unstable) {
tsc_unstable = 1;
- tsc_enabled = 0;
printk("Marking TSC unstable due to: %s.\n", reason);
/* Can be called before registration */
if (clocksource_tsc.mult)
@@ -336,7 +335,7 @@ EXPORT_SYMBOL_GPL(mark_tsc_unstable);
static int __init dmi_mark_tsc_unstable(const struct dmi_system_id *d)
{
printk(KERN_NOTICE "%s detected: marking TSC unstable.\n",
- d->ident);
+ d->ident);
tsc_unstable = 1;
return 0;
}
@@ -403,8 +402,11 @@ void __init tsc_init(void)
{
int cpu;
- if (!cpu_has_tsc)
+ if (!cpu_has_tsc || tsc_disabled) {
+ /* Disable the TSC in case of !cpu_has_tsc */
+ tsc_disabled = 1;
return;
+ }
cpu_khz = calculate_cpu_khz();
tsc_khz = cpu_khz;
@@ -441,8 +443,6 @@ void __init tsc_init(void)
if (check_tsc_unstable()) {
clocksource_tsc.rating = 0;
clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
- } else
- tsc_enabled = 1;
-
+ }
clocksource_register(&clocksource_tsc);
}