[patch 19/49] x86: dont use tsc_khz to calculate lpj if notsc is passed

Greg KH
2008-11-12T00:33:32Z

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2.6.27-stable review patch. If anyone has any objections, please let us know.

------------------

From: Alok Kataria <akataria@vmware.com>

commit 70de9a97049e0ba79dc040868564408d5ce697f9 upstream

Impact: fix udelay when "notsc" boot parameter is passed

With notsc passed on commandline, tsc may not be used for
udelays, make sure that we do not use tsc_khz to calculate
the lpj value in such cases.

Reported-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Alok N Kataria <akataria@vmware.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/x86/kernel/tsc.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -639,10 +639,6 @@ void __init tsc_init(void)
cpu_khz = calibrate_cpu();
#endif

- lpj = ((u64)tsc_khz * 1000);
- do_div(lpj, HZ);
- lpj_fine = lpj;
-
printk("Detected %lu.%03lu MHz processor.\n",
(unsigned long)cpu_khz / 1000,
(unsigned long)cpu_khz % 1000);
@@ -662,6 +658,10 @@ void __init tsc_init(void)
/* now allow native_sched_clock() to use rdtsc */
tsc_disabled = 0;

+ lpj = ((u64)tsc_khz * 1000);
+ do_div(lpj, HZ);
+ lpj_fine = lpj;
+
use_tsc_delay();
/* Check and install the TSC clocksource */
dmi_check_system(bad_tsc_dmi_table);

--