linux/arch
Peter Zijlstra 30c7e5b123 x86/tsc: Allow TSC calibration without PIT
Zhang Rui reported that a Surface Pro 4 will fail to boot with
lapic=notscdeadline. Part of the problem is that that machine doesn't have
a PIT.

If, for some reason, the TSC init has to fall back to TSC calibration, it
relies on the PIT to be present.

Allow TSC calibration to reliably fall back to HPET.

The below results in an accurate TSC measurement when forced on a IVB:

  tsc: Unable to calibrate against PIT
  tsc: No reference (HPET/PMTIMER) available
  tsc: Unable to calibrate against PIT
  tsc: using HPET reference calibration
  tsc: Detected 2792.451 MHz processor

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: len.brown@intel.com
Cc: rui.zhang@intel.com
Link: https://lkml.kernel.org/r/20171222092243.333145937@infradead.org
2018-01-14 20:18:23 +01:00
..
alpha bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
arc bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
arm kernel/exit.c: export abort() to modules 2018-01-04 16:45:09 -08:00
arm64 ARM: SoC fixes for 4.15 2018-01-04 11:14:36 -08:00
blackfin bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
c6x bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
cris bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
frv bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
h8300 bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
hexagon bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
ia64 bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
m32r kernel/exit.c: export abort() to modules 2018-01-04 16:45:09 -08:00
m68k Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-12-08 13:32:44 -08:00
metag bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
microblaze bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
mips Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-12-08 13:32:44 -08:00
mn10300 bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
nios2 bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
openrisc bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
parisc parisc: Reduce thread stack to 16 kb 2017-12-17 21:06:25 +01:00
powerpc kernel/irq: Extend lockdep class for request mutex 2017-12-28 12:26:35 +01:00
riscv RISC-V: Remove unused CONFIG_HVC_RISCV_SBI code 2017-12-11 07:51:09 -08:00
s390 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2018-01-05 12:17:33 -08:00
score bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
sh bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
sparc sparc64: repair calling incorrect hweight function from stubs 2017-12-27 20:29:48 -05:00
tile bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
um Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-23 11:53:04 -08:00
unicore32 kernel/exit.c: export abort() to modules 2018-01-04 16:45:09 -08:00
x86 x86/tsc: Allow TSC calibration without PIT 2018-01-14 20:18:23 +01:00
xtensa bpf: correct broken uapi for BPF_PROG_TYPE_PERF_EVENT program type 2017-12-05 15:02:40 +01:00
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