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author | Pavel Tatashin <pasha.tatashin@oracle.com> | 2018-07-19 16:55:45 -0400 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2018-07-20 00:02:44 +0200 |
commit | 8dbe438589f373544a1af8b4a859e4da853c0f90 (patch) | |
tree | d5677d86892654b28d3db26bae192b3ece2637b3 /arch/x86/kernel/tsc.c | |
parent | 03821f451d2d2d7599061244734245be139014ea (diff) | |
download | linux-stable-8dbe438589f373544a1af8b4a859e4da853c0f90.tar.gz linux-stable-8dbe438589f373544a1af8b4a859e4da853c0f90.tar.bz2 linux-stable-8dbe438589f373544a1af8b4a859e4da853c0f90.zip |
x86/tsc: Make use of tsc_calibrate_cpu_early()
During early boot enable tsc_calibrate_cpu_early() and switch to
tsc_calibrate_cpu() only later. Do this unconditionally, because it is
unknown what methods other cpus will use to calibrate once they are
onlined.
If by the time tsc_init() is called tsc frequency is still unknown do only
pit_hpet_ptimer_calibrate_cpu() to calibrate, as this function contains the
only methods wich have not been called and tried earlier.
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: steven.sistare@oracle.com
Cc: daniel.m.jordan@oracle.com
Cc: linux@armlinux.org.uk
Cc: schwidefsky@de.ibm.com
Cc: heiko.carstens@de.ibm.com
Cc: john.stultz@linaro.org
Cc: sboyd@codeaurora.org
Cc: hpa@zytor.com
Cc: douly.fnst@cn.fujitsu.com
Cc: peterz@infradead.org
Cc: prarit@redhat.com
Cc: feng.tang@intel.com
Cc: pmladek@suse.com
Cc: gnomes@lxorguk.ukuu.org.uk
Cc: linux-s390@vger.kernel.org
Cc: boris.ostrovsky@oracle.com
Cc: jgross@suse.com
Cc: pbonzini@redhat.com
Link: https://lkml.kernel.org/r/20180719205545.16512-27-pasha.tatashin@oracle.com
Diffstat (limited to 'arch/x86/kernel/tsc.c')
-rw-r--r-- | arch/x86/kernel/tsc.c | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 60586779b02c..02e416b87ac1 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -854,7 +854,7 @@ unsigned long native_calibrate_cpu_early(void) /** * native_calibrate_cpu - calibrate the cpu */ -unsigned long native_calibrate_cpu(void) +static unsigned long native_calibrate_cpu(void) { unsigned long tsc_freq = native_calibrate_cpu_early(); @@ -1374,13 +1374,19 @@ unreg: */ device_initcall(init_tsc_clocksource); -static bool __init determine_cpu_tsc_frequencies(void) +static bool __init determine_cpu_tsc_frequencies(bool early) { /* Make sure that cpu and tsc are not already calibrated */ WARN_ON(cpu_khz || tsc_khz); - cpu_khz = x86_platform.calibrate_cpu(); - tsc_khz = x86_platform.calibrate_tsc(); + if (early) { + cpu_khz = x86_platform.calibrate_cpu(); + tsc_khz = x86_platform.calibrate_tsc(); + } else { + /* We should not be here with non-native cpu calibration */ + WARN_ON(x86_platform.calibrate_cpu != native_calibrate_cpu); + cpu_khz = pit_hpet_ptimer_calibrate_cpu(); + } /* * Trust non-zero tsc_khz as authorative, @@ -1419,7 +1425,7 @@ void __init tsc_early_init(void) { if (!boot_cpu_has(X86_FEATURE_TSC)) return; - if (!determine_cpu_tsc_frequencies()) + if (!determine_cpu_tsc_frequencies(true)) return; loops_per_jiffy = get_loops_per_jiffy(); @@ -1431,6 +1437,13 @@ void __init tsc_early_init(void) void __init tsc_init(void) { + /* + * native_calibrate_cpu_early can only calibrate using methods that are + * available early in boot. + */ + if (x86_platform.calibrate_cpu == native_calibrate_cpu_early) + x86_platform.calibrate_cpu = native_calibrate_cpu; + if (!boot_cpu_has(X86_FEATURE_TSC)) { setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); return; @@ -1438,7 +1451,7 @@ void __init tsc_init(void) if (!tsc_khz) { /* We failed to determine frequencies earlier, try again */ - if (!determine_cpu_tsc_frequencies()) { + if (!determine_cpu_tsc_frequencies(false)) { mark_tsc_unstable("could not calculate TSC khz"); setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); return; |