diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2008-05-13 12:31:00 +0200 |
|---|---|---|
| committer | Chris Wright <chrisw@sous-sol.org> | 2008-06-09 11:27:02 -0700 |
| commit | 94aa6550e8668fab1997e2d57a48b22cf68090b2 (patch) | |
| tree | 0ce699538150017d3e4e16b1ed79f3c15de73696 /arch | |
| parent | cf8ec9fd81d2be5cdcd978ca7ca1977d0548d7cb (diff) | |
x86: distangle user disabled TSC from unstable
upstream commit: 9ccc906c97e34fd91dc6aaf5b69b52d824386910
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>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/tsc_32.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/arch/x86/kernel/tsc_32.c b/arch/x86/kernel/tsc_32.c index 68657d8526fb..021723ccd507 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 @@ -121,7 +121,7 @@ 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); @@ -310,7 +310,6 @@ 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) @@ -324,7 +323,7 @@ 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; } @@ -391,8 +390,11 @@ 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; @@ -429,8 +431,6 @@ 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); } |