[PATCH 0/3 v12] printk: Add new timestamps

From: Prarit Bhargava
Date: Mon Sep 18 2017 - 13:52:03 EST

printk.time=1/CONFIG_PRINTK_TIME=1 adds a unmodified local hardware clock
timestamp to printk messages. The local hardware clock loses time each
day making it difficult to determine exactly when an issue has occurred in
the kernel log, and making it difficult to determine how kernel and
hardware issues relate to each other in real time.

Add monotonic, boottime, and real clock timestamps in addition to the existing
local hardware clock timestamp.

Changes from v12: In 1/3 remove typecast. In 3/3, Reword Kconfig names,
simplify timestamp logic and remove recursive code.

Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Mark Salyzyn <salyzyn@xxxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Petr Mladek <pmladek@xxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Christoffer Dall <cdall@xxxxxxxxxx>
Cc: Deepa Dinamani <deepa.kernel@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Joel Fernandes <joelaf@xxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Cc: "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
Cc: Olof Johansson <olof@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: linux-doc@xxxxxxxxxxxxxxx
[jstultz: reworked Kconfig settings to avoid defconfig noise]
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>

Prarit Bhargava (2):
time: Make fast functions return 0 before timekeeping is initialized
printk: Add monotonic, boottime, and realtime timestamps

Thomas Gleixner (1):
timekeeping: Provide NMI safe access to clock realtime

Documentation/admin-guide/kernel-parameters.txt | 6 +-
include/linux/timekeeper_internal.h | 6 +-
include/linux/timekeeping.h | 1 +
kernel/printk/printk.c | 130 +++++++++++++++++++++++-
kernel/time/timekeeping.c | 60 +++++++++--
lib/Kconfig.debug | 48 ++++++++-
6 files changed, 233 insertions(+), 18 deletions(-)