x86: don't use tsc_khz to calculate lpj if notsc is passed

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>

diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 8f98e9d..de850e9 100644 (file)
--- 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);