[PATCH v5 0/2] Early boot time stamps for x86

[Pavel Tatashin]

changelog
---------
v4 - v5 - Fix compiler warnings on systems with stable clocks.
v3 - v4
	- Fixed tsc_early_fini() call to be in the 2nd patch as reported
	  by Dou Liyang
	- Improved comment before __use_sched_clock_early to explain why
	  we need both booleans.
	- Simplified valid_clock logic in read_boot_clock64().

v2 - v3
	- Addressed comment from Thomas Gleixner
	- Timestamps are available a little later in boot but still much
	  earlier than in mainline. This significantly simplified this
	  work.
v1 - v2
	In patch "x86/tsc: tsc early":
	- added tsc_adjusted_early()
	- fixed 32-bit compile error use do_div()

Adding early boot time stamps support for x86 machines.
SPARC patches for early boot time stamps are already integrated into
mainline linux.

Sample output
-------------
Before:
https://hastebin.com/jadaqukubu.scala

After:
https://hastebin.com/nubipozacu.scala

As seen above, currently timestamps are available from around the time when
"Security Framework" is initialized. But, 26s already passed until we
reached to this point.
Pavel Tatashin (2):
  sched/clock: interface to allow timestamps early in boot
  x86/tsc: use tsc early

 arch/x86/include/asm/tsc.h  |  4 +++
 arch/x86/kernel/setup.c     | 10 +++++--
 arch/x86/kernel/time.c      | 24 +++++++++++++++++
 arch/x86/kernel/tsc.c       | 47 +++++++++++++++++++++++++++++++++
 include/linux/sched/clock.h |  4 +++
 kernel/sched/clock.c        | 64 ++++++++++++++++++++++++++++++++++++++++++++-
 6 files changed, 150 insertions(+), 3 deletions(-)

-- 
2.14.1