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63ec58b44f
linux/arch/x86/kernel
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Michael Zhivich 63ec58b44f x86/tsc: Respect tsc command line paraemeter for clocksource_tsc_early 
The introduction of clocksource_tsc_early broke the functionality of
"tsc=reliable" and "tsc=nowatchdog" command line parameters, since
clocksource_tsc_early is unconditionally registered with
CLOCK_SOURCE_MUST_VERIFY and thus put on the watchdog list.

This can cause the TSC to be declared unstable during boot:

  clocksource: timekeeping watchdog on CPU0: Marking clocksource
               'tsc-early' as unstable because the skew is too large:
  clocksource: 'refined-jiffies' wd_now: fffb7018 wd_last: fffb6e9d
               mask: ffffffff
  clocksource: 'tsc-early' cs_now: 68a6a7070f6a0 cs_last: 68a69ab6f74d6
               mask: ffffffffffffffff
  tsc: Marking TSC unstable due to clocksource watchdog

The corresponding elapsed times are cs_nsec=1224152026 and wd_nsec=378942392, so
the watchdog differs from TSC by 0.84 seconds.

This happens when HPET is not available and jiffies are used as the TSC
watchdog instead and the jiffies update is not happening due to lost timer
interrupts in periodic mode, which can happen e.g. with expensive debug
mechanisms enabled or under massive overload conditions in virtualized
environments.

Before the introduction of the early TSC clocksource the command line
parameters "tsc=reliable" and "tsc=nowatchdog" could be used to work around
this issue.

Restore the behaviour by disabling the watchdog if requested on the kernel
command line.

[ tglx: Clarify changelog ]

Fixes: aa83c45762 ("x86/tsc: Introduce early tsc clocksource")
Signed-off-by: Michael Zhivich <mzhivich@akamai.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20191024175945.14338-1-mzhivich@akamai.com
2019-11-05 01:24:56 +01:00
..
acpi Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
apic x86/apic/32: Avoid bogus LDR warnings 2019-11-05 00:11:00 +01:00
cpu x86/resctrl: Prevent NULL pointer dereference when reading mondata 2019-11-03 17:51:22 +01:00
fpu Merge branch 'x86-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 17:28:57 -07:00
kprobes Merge branch 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-16 18:47:53 -07:00
.gitignore
alternative.c x86: Correct misc typos 2019-09-02 14:02:59 +02:00
amd_gart_64.c dma-mapping: provide a better default ->get_required_mask 2019-09-04 11:13:19 +02:00
amd_nb.c x86/amd_nb: Add PCI device IDs for family 17h, model 70h 2019-09-03 12:47:17 -07:00
apb_timer.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
aperture_64.c x86/gart: Exclude GART aperture from kcore 2019-03-23 12:11:49 +01:00
apm_32.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 118 2019-05-24 17:39:02 +02:00
asm-offsets_32.c
asm-offsets_64.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-17 12:04:39 -07:00
asm-offsets.c x86/paravirt: Make read_cr2() CALLEE_SAVE 2019-07-17 23:17:37 +02:00
audit_64.c
bootflag.c
check.c x86/headers: Fix -Wmissing-prototypes warning 2018-11-23 07:59:59 +01:00
cpuid.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 142 2019-05-30 11:25:17 -07:00
crash_dump_32.c
crash_dump_64.c fs/core/vmcore: Move sev_active() reference to x86 arch code 2019-08-09 22:52:10 +10:00
crash.c x86/crash: Remove unnecessary comparison 2019-07-24 16:50:15 +02:00
devicetree.c x86/headers: Fix -Wmissing-prototypes warning 2018-11-23 07:59:59 +01:00
doublefault.c
dumpstack_32.c x86/irq/32: Rename hard/softirq_stack to hard/softirq_stack_ptr 2019-04-17 15:24:18 +02:00
dumpstack_64.c x86/dumpstack/64: Don't evaluate exception stacks before setup 2019-11-05 00:51:35 +01:00
dumpstack.c x86/dumpstack: Indicate PREEMPT_RT in dumps 2019-07-31 19:03:36 +02:00
e820.c x86/e820: Use proper booleans instead of 0/1 2019-07-16 23:13:49 +02:00
early_printk.c efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation 2019-02-04 08:27:30 +01:00
early-quirks.c x86/gpu: add TGL stolen memory support 2019-07-17 14:46:21 -07:00
ebda.c
eisa.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 243 2019-06-19 17:09:07 +02:00
espfix_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288 2019-06-05 17:36:37 +02:00
ftrace_32.S x86/stackframe/32: Provide consistent pt_regs 2019-06-25 10:23:47 +02:00
ftrace_64.S x86/stackframe, x86/ftrace: Add pt_regs frame annotations 2019-06-25 10:23:47 +02:00
ftrace.c The main changes in this release include: 2019-07-18 11:51:00 -07:00
head32.c x86/boot: Mostly revert commit ae7e1238e6 ("Add ACPI RSDP address to setup_header") 2018-11-20 09:43:10 +01:00
head64.c x86/boot/64: Make level2_kernel_pgt pages invalid outside kernel area 2019-10-11 18:38:15 +02:00
head_32.S
head_64.S x86/irq/64: Update stale comment 2019-07-22 10:54:27 +02:00
hpet.c x86/hpet: Undo the early counter is counting check 2019-07-25 12:21:32 +02:00
hw_breakpoint.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
i8237.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
i8253.c x86/timer: Skip PIT initialization on modern chipsets 2019-06-29 11:35:35 +02:00
i8259.c
idt.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 11:22:57 -07:00
ima_arch.c Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
io_delay.c x86/io_delay: Define IO_DELAY macros in C instead of Kconfig 2019-05-24 08:46:06 +02:00
ioport.c x86: Lock down IO port access when the kernel is locked down 2019-08-19 21:54:16 -07:00
irq_32.c x86/irq: Move IS_ERR_OR_NULL() check into common do_IRQ() code 2019-08-19 23:19:06 +02:00
irq_64.c x86/irq: Move IS_ERR_OR_NULL() check into common do_IRQ() code 2019-08-19 23:19:06 +02:00
irq_work.c
irq.c x86/irq: Check for VECTOR_UNUSED directly 2019-08-19 23:19:07 +02:00
irqflags.S
irqinit.c x86/irq/32: Handle irq stack allocation failure proper 2019-04-17 15:31:42 +02:00
itmt.c proc/sysctl: add shared variables for range check 2019-07-18 17:08:07 -07:00
jailhouse.c x86: Add "nopv" parameter to disable PV extensions 2019-07-17 08:09:58 +02:00
jump_label.c x86/jump_label: Make tp_vec_nr static 2019-06-25 09:22:14 +02:00
kdebugfs.c Driver Core and debugfs changes for 5.3-rc1 2019-07-12 12:24:03 -07:00
kexec-bzimage64.c Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
kgdb.c x86/apic: Provide and use helper for send_IPI_allbutself() 2019-07-25 16:12:00 +02:00
ksysfs.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
kvm.c * s390: ioctl hardening, selftests 2019-09-18 09:49:13 -07:00
kvmclock.c x86: kvmguest: use TSC clocksource if invariant TSC is exposed 2019-02-20 22:48:52 +01:00
ldt.c x86: Convert some slow-path static_cpu_has() callers to boot_cpu_has() 2019-04-08 12:13:34 +02:00
livepatch.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 13 2019-05-21 11:28:45 +02:00
machine_kexec_32.c x86/mm: Remove set_pages_x() and set_pages_nx() 2019-09-03 09:26:37 +02:00
machine_kexec_64.c Merge branch 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-09 11:52:34 -07:00
Makefile Merge branch 'x86-paravirt-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 17:34:44 -07:00
mmconf-fam10h_64.c
module.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
mpparse.c x86/boot: Fix memory leak in default_get_smp_config() 2019-07-16 23:13:48 +02:00
msr.c x86/msr: Restrict MSR access when the kernel is locked down 2019-08-19 21:54:16 -07:00
nmi_selftest.c
nmi.c x86/hotplug: Silence APIC and NMI when CPU is dead 2019-07-25 16:11:59 +02:00
paravirt_patch.c x86/paravirt: Standardize 'insn_buff' variable names 2019-04-29 16:05:49 +02:00
paravirt-spinlocks.c x86/paravirt: Use a single ops structure 2018-09-03 16:50:35 +02:00
paravirt.c x86/paravirt: Drop {read,write}_cr8() hooks 2019-07-22 10:12:33 +02:00
pci-calgary_64.c dma-mapping: explicitly wire up ->mmap and ->get_sgtable 2019-09-04 11:13:18 +02:00
pci-dma.c x86/dma: Get rid of iommu_pass_through 2019-08-23 10:11:01 +02:00
pci-iommu_table.c
pci-swiotlb.c dma-mapping: fix filename references 2019-09-03 08:36:30 +02:00
pcspeaker.c
perf_regs.c perf/x86/regs: Check reserved bits 2019-06-24 19:19:24 +02:00
platform-quirks.c
pmem.c
probe_roms.c
process_32.c x86/stackframe/32: Provide consistent pt_regs 2019-06-25 10:23:47 +02:00
process_64.c x86/process: Delete useless check for dead process with LDT 2019-07-17 00:42:27 +02:00
process.c add cpuidle-haltpoll driver 2019-07-30 17:27:37 +02:00
process.h x86: Use the correct SPDX License Identifier in headers 2019-10-01 20:31:35 +02:00
ptrace.c x86/ptrace: Mark expected switch fall-through 2019-08-07 15:12:01 +02:00
pvclock.c x86/vdso: Switch to generic vDSO implementation 2019-06-22 21:21:10 +02:00
quirks.c x86/PCI: Remove superfluous returns from void functions 2019-08-20 09:54:36 +02:00
reboot_fixups_32.c
reboot.c x86/apic: Provide and use helper for send_IPI_allbutself() 2019-07-25 16:12:00 +02:00
relocate_kernel_32.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
relocate_kernel_64.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
resource.c
rtc.c
setup_percpu.c x86/irq/64: Split the IRQ stack into its own pages 2019-04-17 15:37:02 +02:00
setup.c dma-mapping: fix filename references 2019-09-03 08:36:30 +02:00
signal_compat.c
signal.c x86: use static_cpu_has in uaccess region to avoid instrumentation 2019-07-12 11:05:42 -07:00
smp.c x86/smp: Move smp_function_call implementations into IPI code 2019-07-25 16:12:01 +02:00
smpboot.c Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-09-17 12:04:39 -07:00
stacktrace.c x86/stacktrace: Prevent access_ok() warnings in arch_stack_walk_user() 2019-07-22 10:42:36 +02:00
step.c
sys_x86_64.c x86/compat: Adjust in_compat_syscall() to generic code under !COMPAT 2018-11-01 12:59:25 +01:00
sysfb_efi.c x86/sysfb_efi: Add quirks for some devices with swapped width and height 2019-07-22 10:47:11 +02:00
sysfb_simplefb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
sysfb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
tboot.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335 2019-06-05 17:37:06 +02:00
tce_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156 2019-05-30 11:26:35 -07:00
time.c Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:59:34 -07:00
tls.c x86/tls: Fix possible spectre-v1 in do_get_thread_area() 2019-06-27 23:48:04 +02:00
tls.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 193 2019-05-30 11:29:21 -07:00
topology.c x86/topology: Make DEBUG_HOTPLUG_CPU0 pr_info() more descriptive 2019-04-19 19:42:57 +02:00
trace_clock.c
tracepoint.c x86/kernel: Fix more -Wmissing-prototypes warnings 2018-12-08 12:24:35 +01:00
traps.c x86/mm, tracing: Fix CR2 corruption 2019-07-17 23:17:38 +02:00
tsc_msr.c x86/cpu: Update init data for new Airmont CPU model 2019-09-06 07:30:40 +02:00
tsc_sync.c
tsc.c x86/tsc: Respect tsc command line paraemeter for clocksource_tsc_early 2019-11-05 01:24:56 +01:00
umip.c x86/umip: Add emulation (spoofing) for UMIP covered instructions in 64-bit processes as well 2019-09-10 08:36:16 +02:00
unwind_frame.c x86/stackframe/32: Provide consistent pt_regs 2019-06-25 10:23:47 +02:00
unwind_guess.c treewide: Add SPDX license identifier for missed files 2019-05-21 10:50:45 +02:00
unwind_orc.c Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-08 16:59:34 -07:00
uprobes.c uprobes/x86: Fix detection of 32-bit user mode 2019-08-26 15:55:09 +02:00
verify_cpu.S treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 230 2019-06-19 17:09:06 +02:00
vm86_32.c signal: Remove task parameter from force_sig 2019-05-27 09:36:28 -05:00
vmlinux.lds.S Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-07-11 13:54:00 -07:00
vsmp_64.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 346 2019-06-05 17:37:08 +02:00
x86_init.c Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00