From 8dbe438589f373544a1af8b4a859e4da853c0f90 Mon Sep 17 00:00:00 2001 From: Pavel Tatashin Date: Thu, 19 Jul 2018 16:55:45 -0400 Subject: 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 Signed-off-by: Thomas Gleixner 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 --- arch/x86/include/asm/tsc.h | 1 - arch/x86/kernel/tsc.c | 25 +++++++++++++++++++------ arch/x86/kernel/x86_init.c | 2 +- 3 files changed, 20 insertions(+), 8 deletions(-) (limited to 'arch') diff --git a/arch/x86/include/asm/tsc.h b/arch/x86/include/asm/tsc.h index 88140e4f2292..eb5bbfeccb66 100644 --- a/arch/x86/include/asm/tsc.h +++ b/arch/x86/include/asm/tsc.h @@ -39,7 +39,6 @@ extern void mark_tsc_unstable(char *reason); extern int unsynchronized_tsc(void); extern int check_tsc_unstable(void); extern void mark_tsc_async_resets(char *reason); -extern unsigned long native_calibrate_cpu(void); extern unsigned long native_calibrate_cpu_early(void); extern unsigned long native_calibrate_tsc(void); extern unsigned long long native_sched_clock_from_tsc(u64 tsc); 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; diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c index 3ab867603e81..2792b5573818 100644 --- a/arch/x86/kernel/x86_init.c +++ b/arch/x86/kernel/x86_init.c @@ -109,7 +109,7 @@ struct x86_cpuinit_ops x86_cpuinit = { static void default_nmi_init(void) { }; struct x86_platform_ops x86_platform __ro_after_init = { - .calibrate_cpu = native_calibrate_cpu, + .calibrate_cpu = native_calibrate_cpu_early, .calibrate_tsc = native_calibrate_tsc, .get_wallclock = mach_get_cmos_time, .set_wallclock = mach_set_rtc_mmss, -- cgit v1.2.3-59-g8ed1b