[PATCH 0/2] printk: allow different timestamps for printk.time

[PATCH 0/2] printk: allow different timestamps for printk.time

[Prarit Bhargava]

Over the past years I've seen many reports of bugs that include
time-stamped kernel logs (enabled when CONFIG_PRINTK_TIME=y or
print.time=1 is specified as a kernel parameter) that do not align
with either external time stamped logs or /var/log/messages.  This
also makes determining the time of a failure difficult in cases where
/var/log/messages is unavailable.

For example,

[root@intel-wildcatpass-06 ~]# date; echo "Hello!" > /dev/kmsg ; date
Thu Jul 20 11:38:22 EST 2017
Thu Jul 20 11:38:22 EST 2017

which displays

[83973.768912] Hello!

on the serial console.

Running a script to convert this to the stamped time,

[root@intel-wildcatpass-06 ~]# ./human.sh  | tail -1
[Thu July 17 11:39:45 2017] Hello!

which is already off by 1 minute and 23 seconds off after ~24 hours of
uptime.

This occurs because the printk time stamp is obtained from a call to
local_clock() which (on x86) is a direct call to the hardware.  These
hardware clock reads are not modified by the standard ntp or ptp protocol
The other timestamps are and that results in situations external
time sources are further and further offset from the kernel log
timestamps.

Implement printk.time settings to allow a user to specify the monotonic
or real clocks.  The default is the local clock (hardware clock).

Real clock & 32-bit systems:  Selecting the real clock printk timestamp may
lead to unlikely situations where a timestamp is wrong because the real time
offset is read without the protection of a sequence lock in the call to
ktime_get_log_ts() in printk_get_ts().

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Christoffer Dall <cdall@linaro.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-doc@vger.kernel.org

Prarit Bhargava (2):
  printk: Make CONFIG_PRINTK_TIME an int
  printk: Add boottime and real timestamps

 Documentation/admin-guide/kernel-parameters.txt    |  6 +-
 arch/arm/configs/aspeed_g4_defconfig               |  2 +-
 arch/arm/configs/aspeed_g5_defconfig               |  2 +-
 arch/arm/configs/axm55xx_defconfig                 |  2 +-
 arch/arm/configs/bcm2835_defconfig                 |  2 +-
 arch/arm/configs/colibri_pxa270_defconfig          |  2 +-
 arch/arm/configs/colibri_pxa300_defconfig          |  2 +-
 arch/arm/configs/dove_defconfig                    |  2 +-
 arch/arm/configs/efm32_defconfig                   |  2 +-
 arch/arm/configs/exynos_defconfig                  |  2 +-
 arch/arm/configs/ezx_defconfig                     |  2 +-
 arch/arm/configs/h5000_defconfig                   |  2 +-
 arch/arm/configs/hisi_defconfig                    |  2 +-
 arch/arm/configs/imote2_defconfig                  |  2 +-
 arch/arm/configs/imx_v6_v7_defconfig               |  2 +-
 arch/arm/configs/keystone_defconfig                |  2 +-
 arch/arm/configs/lpc18xx_defconfig                 |  2 +-
 arch/arm/configs/magician_defconfig                |  2 +-
 arch/arm/configs/mmp2_defconfig                    |  2 +-
 arch/arm/configs/moxart_defconfig                  |  2 +-
 arch/arm/configs/mps2_defconfig                    |  2 +-
 arch/arm/configs/multi_v7_defconfig                |  2 +-
 arch/arm/configs/mvebu_v7_defconfig                |  2 +-
 arch/arm/configs/mxs_defconfig                     |  2 +-
 arch/arm/configs/omap2plus_defconfig               |  2 +-
 arch/arm/configs/pxa168_defconfig                  |  2 +-
 arch/arm/configs/pxa3xx_defconfig                  |  2 +-
 arch/arm/configs/pxa910_defconfig                  |  2 +-
 arch/arm/configs/pxa_defconfig                     |  2 +-
 arch/arm/configs/qcom_defconfig                    |  2 +-
 arch/arm/configs/raumfeld_defconfig                |  2 +-
 arch/arm/configs/shmobile_defconfig                |  2 +-
 arch/arm/configs/socfpga_defconfig                 |  2 +-
 arch/arm/configs/stm32_defconfig                   |  2 +-
 arch/arm/configs/sunxi_defconfig                   |  2 +-
 arch/arm/configs/tango4_defconfig                  |  2 +-
 arch/arm/configs/tegra_defconfig                   |  2 +-
 arch/arm/configs/u300_defconfig                    |  2 +-
 arch/arm/configs/u8500_defconfig                   |  2 +-
 arch/arm/configs/vt8500_v6_v7_defconfig            |  2 +-
 arch/arm/configs/xcep_defconfig                    |  2 +-
 arch/arm/configs/zx_defconfig                      |  2 +-
 arch/arm64/configs/defconfig                       |  2 +-
 arch/m68k/configs/amcore_defconfig                 |  2 +-
 arch/mips/configs/ath25_defconfig                  |  2 +-
 arch/mips/configs/bcm47xx_defconfig                |  2 +-
 arch/mips/configs/bmips_be_defconfig               |  2 +-
 arch/mips/configs/bmips_stb_defconfig              |  2 +-
 arch/mips/configs/ci20_defconfig                   |  2 +-
 arch/mips/configs/generic_defconfig                |  2 +-
 arch/mips/configs/lemote2f_defconfig               |  2 +-
 arch/mips/configs/loongson3_defconfig              |  2 +-
 arch/mips/configs/nlm_xlp_defconfig                |  2 +-
 arch/mips/configs/nlm_xlr_defconfig                |  2 +-
 arch/mips/configs/pistachio_defconfig              |  2 +-
 arch/mips/configs/qi_lb60_defconfig                |  2 +-
 arch/mips/configs/rt305x_defconfig                 |  2 +-
 arch/mips/configs/xway_defconfig                   |  2 +-
 arch/parisc/configs/generic-64bit_defconfig        |  2 +-
 arch/powerpc/configs/40x/virtex_defconfig          |  2 +-
 arch/powerpc/configs/44x/fsp2_defconfig            |  2 +-
 arch/powerpc/configs/44x/virtex5_defconfig         |  2 +-
 arch/powerpc/configs/44x/warp_defconfig            |  2 +-
 arch/powerpc/configs/52xx/cm5200_defconfig         |  2 +-
 arch/powerpc/configs/52xx/lite5200b_defconfig      |  2 +-
 arch/powerpc/configs/52xx/motionpro_defconfig      |  2 +-
 arch/powerpc/configs/52xx/tqm5200_defconfig        |  2 +-
 arch/powerpc/configs/gamecube_defconfig            |  2 +-
 arch/powerpc/configs/mpc5200_defconfig             |  2 +-
 arch/powerpc/configs/pasemi_defconfig              |  2 +-
 arch/powerpc/configs/wii_defconfig                 |  2 +-
 arch/s390/configs/default_defconfig                |  2 +-
 arch/s390/configs/gcov_defconfig                   |  2 +-
 arch/s390/configs/performance_defconfig            |  2 +-
 arch/s390/configs/zfcpdump_defconfig               |  2 +-
 arch/sh/configs/edosk7760_defconfig                |  2 +-
 arch/sh/configs/sdk7786_defconfig                  |  2 +-
 arch/sh/configs/se7722_defconfig                   |  2 +-
 arch/sh/configs/sh7785lcr_32bit_defconfig          |  2 +-
 arch/sh/configs/urquell_defconfig                  |  2 +-
 arch/sparc/configs/sparc64_defconfig               |  2 +-
 arch/x86/configs/i386_defconfig                    |  2 +-
 arch/x86/configs/x86_64_defconfig                  |  2 +-
 arch/xtensa/configs/audio_kc705_defconfig          |  2 +-
 arch/xtensa/configs/cadence_csp_defconfig          |  2 +-
 arch/xtensa/configs/generic_kc705_defconfig        |  2 +-
 arch/xtensa/configs/nommu_kc705_defconfig          |  2 +-
 arch/xtensa/configs/smp_lx200_defconfig            |  2 +-
 include/linux/timekeeping.h                        |  1 +
 kernel/printk/printk.c                             | 95 +++++++++++++++++++++-
 kernel/time/timekeeping.c                          | 14 ++++
 lib/Kconfig.debug                                  |  8 +-
 .../selftests/rcutorture/configs/lock/CFcommon     |  2 +-
 .../selftests/rcutorture/configs/rcu/CFcommon      |  2 +-
 .../selftests/rcutorture/configs/rcuperf/CFcommon  |  2 +-
 95 files changed, 206 insertions(+), 98 deletions(-)

-- 
1.8.5.5

[PATCH 1/2] printk: Make CONFIG_PRINTK_TIME an int

[Prarit Bhargava]

CONFIG_PRINTK_TIME is a bool and in order to add timestamp options for
the monotonic and real time clock it must be expanded to an int.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Christoffer Dall <cdall@linaro.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-doc@vger.kernel.org


---
 Documentation/admin-guide/kernel-parameters.txt    |  2 +-
 arch/arm/configs/aspeed_g4_defconfig               |  2 +-
 arch/arm/configs/aspeed_g5_defconfig               |  2 +-
 arch/arm/configs/axm55xx_defconfig                 |  2 +-
 arch/arm/configs/bcm2835_defconfig                 |  2 +-
 arch/arm/configs/colibri_pxa270_defconfig          |  2 +-
 arch/arm/configs/colibri_pxa300_defconfig          |  2 +-
 arch/arm/configs/dove_defconfig                    |  2 +-
 arch/arm/configs/efm32_defconfig                   |  2 +-
 arch/arm/configs/exynos_defconfig                  |  2 +-
 arch/arm/configs/ezx_defconfig                     |  2 +-
 arch/arm/configs/h5000_defconfig                   |  2 +-
 arch/arm/configs/hisi_defconfig                    |  2 +-
 arch/arm/configs/imote2_defconfig                  |  2 +-
 arch/arm/configs/imx_v6_v7_defconfig               |  2 +-
 arch/arm/configs/keystone_defconfig                |  2 +-
 arch/arm/configs/lpc18xx_defconfig                 |  2 +-
 arch/arm/configs/magician_defconfig                |  2 +-
 arch/arm/configs/mmp2_defconfig                    |  2 +-
 arch/arm/configs/moxart_defconfig                  |  2 +-
 arch/arm/configs/mps2_defconfig                    |  2 +-
 arch/arm/configs/multi_v7_defconfig                |  2 +-
 arch/arm/configs/mvebu_v7_defconfig                |  2 +-
 arch/arm/configs/mxs_defconfig                     |  2 +-
 arch/arm/configs/omap2plus_defconfig               |  2 +-
 arch/arm/configs/pxa168_defconfig                  |  2 +-
 arch/arm/configs/pxa3xx_defconfig                  |  2 +-
 arch/arm/configs/pxa910_defconfig                  |  2 +-
 arch/arm/configs/pxa_defconfig                     |  2 +-
 arch/arm/configs/qcom_defconfig                    |  2 +-
 arch/arm/configs/raumfeld_defconfig                |  2 +-
 arch/arm/configs/shmobile_defconfig                |  2 +-
 arch/arm/configs/socfpga_defconfig                 |  2 +-
 arch/arm/configs/stm32_defconfig                   |  2 +-
 arch/arm/configs/sunxi_defconfig                   |  2 +-
 arch/arm/configs/tango4_defconfig                  |  2 +-
 arch/arm/configs/tegra_defconfig                   |  2 +-
 arch/arm/configs/u300_defconfig                    |  2 +-
 arch/arm/configs/u8500_defconfig                   |  2 +-
 arch/arm/configs/vt8500_v6_v7_defconfig            |  2 +-
 arch/arm/configs/xcep_defconfig                    |  2 +-
 arch/arm/configs/zx_defconfig                      |  2 +-
 arch/arm64/configs/defconfig                       |  2 +-
 arch/m68k/configs/amcore_defconfig                 |  2 +-
 arch/mips/configs/ath25_defconfig                  |  2 +-
 arch/mips/configs/bcm47xx_defconfig                |  2 +-
 arch/mips/configs/bmips_be_defconfig               |  2 +-
 arch/mips/configs/bmips_stb_defconfig              |  2 +-
 arch/mips/configs/ci20_defconfig                   |  2 +-
 arch/mips/configs/generic_defconfig                |  2 +-
 arch/mips/configs/lemote2f_defconfig               |  2 +-
 arch/mips/configs/loongson3_defconfig              |  2 +-
 arch/mips/configs/nlm_xlp_defconfig                |  2 +-
 arch/mips/configs/nlm_xlr_defconfig                |  2 +-
 arch/mips/configs/pistachio_defconfig              |  2 +-
 arch/mips/configs/qi_lb60_defconfig                |  2 +-
 arch/mips/configs/rt305x_defconfig                 |  2 +-
 arch/mips/configs/xway_defconfig                   |  2 +-
 arch/parisc/configs/generic-64bit_defconfig        |  2 +-
 arch/powerpc/configs/40x/virtex_defconfig          |  2 +-
 arch/powerpc/configs/44x/fsp2_defconfig            |  2 +-
 arch/powerpc/configs/44x/virtex5_defconfig         |  2 +-
 arch/powerpc/configs/44x/warp_defconfig            |  2 +-
 arch/powerpc/configs/52xx/cm5200_defconfig         |  2 +-
 arch/powerpc/configs/52xx/lite5200b_defconfig      |  2 +-
 arch/powerpc/configs/52xx/motionpro_defconfig      |  2 +-
 arch/powerpc/configs/52xx/tqm5200_defconfig        |  2 +-
 arch/powerpc/configs/gamecube_defconfig            |  2 +-
 arch/powerpc/configs/mpc5200_defconfig             |  2 +-
 arch/powerpc/configs/pasemi_defconfig              |  2 +-
 arch/powerpc/configs/wii_defconfig                 |  2 +-
 arch/s390/configs/default_defconfig                |  2 +-
 arch/s390/configs/gcov_defconfig                   |  2 +-
 arch/s390/configs/performance_defconfig            |  2 +-
 arch/s390/configs/zfcpdump_defconfig               |  2 +-
 arch/sh/configs/edosk7760_defconfig                |  2 +-
 arch/sh/configs/sdk7786_defconfig                  |  2 +-
 arch/sh/configs/se7722_defconfig                   |  2 +-
 arch/sh/configs/sh7785lcr_32bit_defconfig          |  2 +-
 arch/sh/configs/urquell_defconfig                  |  2 +-
 arch/sparc/configs/sparc64_defconfig               |  2 +-
 arch/x86/configs/i386_defconfig                    |  2 +-
 arch/x86/configs/x86_64_defconfig                  |  2 +-
 arch/xtensa/configs/audio_kc705_defconfig          |  2 +-
 arch/xtensa/configs/cadence_csp_defconfig          |  2 +-
 arch/xtensa/configs/generic_kc705_defconfig        |  2 +-
 arch/xtensa/configs/nommu_kc705_defconfig          |  2 +-
 arch/xtensa/configs/smp_lx200_defconfig            |  2 +-
 kernel/printk/printk.c                             | 36 ++++++++++++++++++++--
 lib/Kconfig.debug                                  |  7 +++--
 .../selftests/rcutorture/configs/lock/CFcommon     |  2 +-
 .../selftests/rcutorture/configs/rcu/CFcommon      |  2 +-
 .../selftests/rcutorture/configs/rcuperf/CFcommon  |  2 +-
 93 files changed, 130 insertions(+), 95 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d9c171ce4190..c3b14abf9da4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3189,7 +3189,7 @@
 			Default: ratelimit
 
 	printk.time=	Show timing data prefixed to each printk message line
-			Format: <bool>  (1/Y/y=enable, 0/N/n=disable)
+			Format: <string>  (1/Y/y=enable, 0/N/n=disable)
 
 	processor.max_cstate=	[HW,ACPI]
 			Limit processor to maximum C-state
diff --git a/arch/arm/configs/aspeed_g4_defconfig b/arch/arm/configs/aspeed_g4_defconfig
index cfc2465e8b77..a2eea1ec90a5 100644
--- a/arch/arm/configs/aspeed_g4_defconfig
+++ b/arch/arm/configs/aspeed_g4_defconfig
@@ -162,7 +162,7 @@ CONFIG_JFFS2_FS_XATTR=y
 CONFIG_UBIFS_FS=y
 CONFIG_SQUASHFS=y
 CONFIG_SQUASHFS_XZ=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/arm/configs/aspeed_g5_defconfig b/arch/arm/configs/aspeed_g5_defconfig
index 3c20d93de389..804c353f4cb2 100644
--- a/arch/arm/configs/aspeed_g5_defconfig
+++ b/arch/arm/configs/aspeed_g5_defconfig
@@ -165,7 +165,7 @@ CONFIG_JFFS2_FS_XATTR=y
 CONFIG_UBIFS_FS=y
 CONFIG_SQUASHFS=y
 CONFIG_SQUASHFS_XZ=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/arm/configs/axm55xx_defconfig b/arch/arm/configs/axm55xx_defconfig
index 8e17e7ed1f02..53c5dc35e930 100644
--- a/arch/arm/configs/axm55xx_defconfig
+++ b/arch/arm/configs/axm55xx_defconfig
@@ -231,7 +231,7 @@ CONFIG_NFS_FSCACHE=y
 CONFIG_SUNRPC_DEBUG=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/arm/configs/bcm2835_defconfig b/arch/arm/configs/bcm2835_defconfig
index 3ee9d78c412a..b6b990169fef 100644
--- a/arch/arm/configs/bcm2835_defconfig
+++ b/arch/arm/configs/bcm2835_defconfig
@@ -141,7 +141,7 @@ CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_BOOT_PRINTK_DELAY=y
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
diff --git a/arch/arm/configs/colibri_pxa270_defconfig b/arch/arm/configs/colibri_pxa270_defconfig
index 8995695fc118..b2b498348416 100644
--- a/arch/arm/configs/colibri_pxa270_defconfig
+++ b/arch/arm/configs/colibri_pxa270_defconfig
@@ -144,7 +144,7 @@ CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_FS=y
 CONFIG_DEBUG_KERNEL=y
diff --git a/arch/arm/configs/colibri_pxa300_defconfig b/arch/arm/configs/colibri_pxa300_defconfig
index d282e8b0bf33..9c716b3f7eb9 100644
--- a/arch/arm/configs/colibri_pxa300_defconfig
+++ b/arch/arm/configs/colibri_pxa300_defconfig
@@ -51,7 +51,7 @@ CONFIG_EXT3_FS=y
 CONFIG_NFS_FS=y
 CONFIG_NFS_V3=y
 CONFIG_ROOT_NFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_USER=y
diff --git a/arch/arm/configs/dove_defconfig b/arch/arm/configs/dove_defconfig
index a93cc2fcf791..4d346feafff7 100644
--- a/arch/arm/configs/dove_defconfig
+++ b/arch/arm/configs/dove_defconfig
@@ -118,7 +118,7 @@ CONFIG_NLS_CODEPAGE_850=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_ISO8859_2=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_FS=y
 # CONFIG_SCHED_DEBUG is not set
diff --git a/arch/arm/configs/efm32_defconfig b/arch/arm/configs/efm32_defconfig
index 860d27138e6f..57508965aa77 100644
--- a/arch/arm/configs/efm32_defconfig
+++ b/arch/arm/configs/efm32_defconfig
@@ -92,7 +92,7 @@ CONFIG_EXT2_FS=y
 CONFIG_ROMFS_FS=y
 CONFIG_ROMFS_BACKED_BY_MTD=y
 # CONFIG_NETWORK_FILESYSTEMS is not set
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
diff --git a/arch/arm/configs/exynos_defconfig b/arch/arm/configs/exynos_defconfig
index 25325ed9319e..c8e3e50e11b7 100644
--- a/arch/arm/configs/exynos_defconfig
+++ b/arch/arm/configs/exynos_defconfig
@@ -253,7 +253,7 @@ CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/arm/configs/ezx_defconfig b/arch/arm/configs/ezx_defconfig
index 23660f3d0f7f..0ada33fc3b4c 100644
--- a/arch/arm/configs/ezx_defconfig
+++ b/arch/arm/configs/ezx_defconfig
@@ -363,7 +363,7 @@ CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
 CONFIG_NLS_UTF8=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_FS=y
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_SCHED_DEBUG is not set
diff --git a/arch/arm/configs/h5000_defconfig b/arch/arm/configs/h5000_defconfig
index e90d1dfeb188..b8eeb3746646 100644
--- a/arch/arm/configs/h5000_defconfig
+++ b/arch/arm/configs/h5000_defconfig
@@ -61,7 +61,7 @@ CONFIG_TMPFS=y
 CONFIG_JFFS2_FS=y
 CONFIG_JFFS2_COMPRESSION_OPTIONS=y
 # CONFIG_NETWORK_FILESYSTEMS is not set
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_SCHED_DEBUG is not set
 # CONFIG_DEBUG_BUGVERBOSE is not set
diff --git a/arch/arm/configs/hisi_defconfig b/arch/arm/configs/hisi_defconfig
index b2e340b272ee..4dc0a4a26c2f 100644
--- a/arch/arm/configs/hisi_defconfig
+++ b/arch/arm/configs/hisi_defconfig
@@ -82,7 +82,7 @@ CONFIG_NFS_FS=y
 CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_FS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
diff --git a/arch/arm/configs/imote2_defconfig b/arch/arm/configs/imote2_defconfig
index f204017c26b9..ad64ef5bf1a3 100644
--- a/arch/arm/configs/imote2_defconfig
+++ b/arch/arm/configs/imote2_defconfig
@@ -336,7 +336,7 @@ CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
 CONFIG_NLS_UTF8=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_FS=y
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_SCHED_DEBUG is not set
diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig
index e74de69caeab..7ad72116eea9 100644
--- a/arch/arm/configs/imx_v6_v7_defconfig
+++ b/arch/arm/configs/imx_v6_v7_defconfig
@@ -382,7 +382,7 @@ CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
 # CONFIG_SCHED_DEBUG is not set
diff --git a/arch/arm/configs/keystone_defconfig b/arch/arm/configs/keystone_defconfig
index 1331f6dc456a..51f4a5914059 100644
--- a/arch/arm/configs/keystone_defconfig
+++ b/arch/arm/configs/keystone_defconfig
@@ -200,7 +200,7 @@ CONFIG_NFSD_V3=y
 CONFIG_NFSD_V3_ACL=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_SHIRQ=y
 CONFIG_DEBUG_USER=y
diff --git a/arch/arm/configs/lpc18xx_defconfig b/arch/arm/configs/lpc18xx_defconfig
index 23df2518203d..72db8de33e84 100644
--- a/arch/arm/configs/lpc18xx_defconfig
+++ b/arch/arm/configs/lpc18xx_defconfig
@@ -160,7 +160,7 @@ CONFIG_EXT2_FS=y
 # CONFIG_INOTIFY_USER is not set
 CONFIG_JFFS2_FS=y
 # CONFIG_NETWORK_FILESYSTEMS is not set
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
diff --git a/arch/arm/configs/magician_defconfig b/arch/arm/configs/magician_defconfig
index ec5674c229a3..32ecf552a14d 100644
--- a/arch/arm/configs/magician_defconfig
+++ b/arch/arm/configs/magician_defconfig
@@ -154,7 +154,7 @@ CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_CODEPAGE_1251=m
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_SCHED_DEBUG is not set
 CONFIG_TIMER_STATS=y
diff --git a/arch/arm/configs/mmp2_defconfig b/arch/arm/configs/mmp2_defconfig
index 1eeee7f11d91..b1eb8f2da3a3 100644
--- a/arch/arm/configs/mmp2_defconfig
+++ b/arch/arm/configs/mmp2_defconfig
@@ -74,7 +74,7 @@ CONFIG_NFS_V3=y
 CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_FS=y
 CONFIG_DEBUG_KERNEL=y
diff --git a/arch/arm/configs/moxart_defconfig b/arch/arm/configs/moxart_defconfig
index 2da0d9ee2107..c91605a17074 100644
--- a/arch/arm/configs/moxart_defconfig
+++ b/arch/arm/configs/moxart_defconfig
@@ -123,7 +123,7 @@ CONFIG_EXT3_FS=y
 CONFIG_TMPFS=y
 CONFIG_CONFIGFS_FS=y
 CONFIG_JFFS2_FS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
diff --git a/arch/arm/configs/mps2_defconfig b/arch/arm/configs/mps2_defconfig
index 0bcdec7cc169..ce119cdd1d33 100644
--- a/arch/arm/configs/mps2_defconfig
+++ b/arch/arm/configs/mps2_defconfig
@@ -98,7 +98,7 @@ CONFIG_NFS_V4_1=y
 CONFIG_NFS_V4_2=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
diff --git a/arch/arm/configs/multi_v7_defconfig b/arch/arm/configs/multi_v7_defconfig
index 4d19c1b4b8e7..59e72eeaf7e8 100644
--- a/arch/arm/configs/multi_v7_defconfig
+++ b/arch/arm/configs/multi_v7_defconfig
@@ -929,7 +929,7 @@ CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_LOCKUP_DETECTOR=y
diff --git a/arch/arm/configs/mvebu_v7_defconfig b/arch/arm/configs/mvebu_v7_defconfig
index 69553704f2dc..a9f750c9b162 100644
--- a/arch/arm/configs/mvebu_v7_defconfig
+++ b/arch/arm/configs/mvebu_v7_defconfig
@@ -152,7 +152,7 @@ CONFIG_NLS_CODEPAGE_850=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_ISO8859_2=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/arm/configs/mxs_defconfig b/arch/arm/configs/mxs_defconfig
index e5822ab01b7d..998b3be6d4bf 100644
--- a/arch/arm/configs/mxs_defconfig
+++ b/arch/arm/configs/mxs_defconfig
@@ -167,7 +167,7 @@ CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_CODEPAGE_850=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_ISO8859_15=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_FRAME_WARN=2048
 CONFIG_UNUSED_SYMBOLS=y
diff --git a/arch/arm/configs/omap2plus_defconfig b/arch/arm/configs/omap2plus_defconfig
index a120ae816260..495940dde8fe 100644
--- a/arch/arm/configs/omap2plus_defconfig
+++ b/arch/arm/configs/omap2plus_defconfig
@@ -493,7 +493,7 @@ CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_INFO_SPLIT=y
 CONFIG_DEBUG_INFO_DWARF4=y
diff --git a/arch/arm/configs/pxa168_defconfig b/arch/arm/configs/pxa168_defconfig
index e7c7b91b6de2..3de60f0b5f2c 100644
--- a/arch/arm/configs/pxa168_defconfig
+++ b/arch/arm/configs/pxa168_defconfig
@@ -50,7 +50,7 @@ CONFIG_NFS_V3=y
 CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_DEBUG_PREEMPT is not set
diff --git a/arch/arm/configs/pxa3xx_defconfig b/arch/arm/configs/pxa3xx_defconfig
index bfea6874b0a1..0a579b68c83a 100644
--- a/arch/arm/configs/pxa3xx_defconfig
+++ b/arch/arm/configs/pxa3xx_defconfig
@@ -109,7 +109,7 @@ CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DEBUG_SHIRQ=y
diff --git a/arch/arm/configs/pxa910_defconfig b/arch/arm/configs/pxa910_defconfig
index 3aff71e6dae5..966e606ae100 100644
--- a/arch/arm/configs/pxa910_defconfig
+++ b/arch/arm/configs/pxa910_defconfig
@@ -58,7 +58,7 @@ CONFIG_NFS_V3=y
 CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_DEBUG_PREEMPT is not set
diff --git a/arch/arm/configs/pxa_defconfig b/arch/arm/configs/pxa_defconfig
index 64e3a2a8cede..6a6baf309aa3 100644
--- a/arch/arm/configs/pxa_defconfig
+++ b/arch/arm/configs/pxa_defconfig
@@ -727,7 +727,7 @@ CONFIG_NLS_ASCII=m
 CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 CONFIG_FRAME_WARN=0
diff --git a/arch/arm/configs/qcom_defconfig b/arch/arm/configs/qcom_defconfig
index b02039c712c3..dfc984afc4c7 100644
--- a/arch/arm/configs/qcom_defconfig
+++ b/arch/arm/configs/qcom_defconfig
@@ -231,7 +231,7 @@ CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/arm/configs/raumfeld_defconfig b/arch/arm/configs/raumfeld_defconfig
index e3dc80ead465..f0cf5f178f0f 100644
--- a/arch/arm/configs/raumfeld_defconfig
+++ b/arch/arm/configs/raumfeld_defconfig
@@ -187,7 +187,7 @@ CONFIG_NLS_ISO8859_15=y
 CONFIG_NLS_KOI8_R=y
 CONFIG_NLS_KOI8_U=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_USER=y
diff --git a/arch/arm/configs/shmobile_defconfig b/arch/arm/configs/shmobile_defconfig
index 3c66a422fb4d..ef3a92ebc2fd 100644
--- a/arch/arm/configs/shmobile_defconfig
+++ b/arch/arm/configs/shmobile_defconfig
@@ -218,7 +218,7 @@ CONFIG_NFS_V4_1=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
 # CONFIG_ARM_UNWIND is not set
diff --git a/arch/arm/configs/socfpga_defconfig b/arch/arm/configs/socfpga_defconfig
index 2620ce790db0..25f751956338 100644
--- a/arch/arm/configs/socfpga_defconfig
+++ b/arch/arm/configs/socfpga_defconfig
@@ -155,7 +155,7 @@ CONFIG_NFSD_V3_ACL=y
 CONFIG_NFSD_V4=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DETECT_HUNG_TASK=y
diff --git a/arch/arm/configs/stm32_defconfig b/arch/arm/configs/stm32_defconfig
index 90e5c46913a5..ff2b87638feb 100644
--- a/arch/arm/configs/stm32_defconfig
+++ b/arch/arm/configs/stm32_defconfig
@@ -74,7 +74,7 @@ CONFIG_STM32_ADC=y
 # CONFIG_DNOTIFY is not set
 # CONFIG_INOTIFY_USER is not set
 CONFIG_NLS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
diff --git a/arch/arm/configs/sunxi_defconfig b/arch/arm/configs/sunxi_defconfig
index 0ec1d1ec130f..b5ef2a35dcc5 100644
--- a/arch/arm/configs/sunxi_defconfig
+++ b/arch/arm/configs/sunxi_defconfig
@@ -151,6 +151,6 @@ CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_FS=y
 CONFIG_CRYPTO_DEV_SUN4I_SS=y
diff --git a/arch/arm/configs/tango4_defconfig b/arch/arm/configs/tango4_defconfig
index 68725d4eae45..2c6a9dca57f9 100644
--- a/arch/arm/configs/tango4_defconfig
+++ b/arch/arm/configs/tango4_defconfig
@@ -90,5 +90,5 @@ CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=m
 CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_UTF8=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_CRYPTO_ECHAINIV is not set
diff --git a/arch/arm/configs/tegra_defconfig b/arch/arm/configs/tegra_defconfig
index f0efc854b5a2..4253b642b008 100644
--- a/arch/arm/configs/tegra_defconfig
+++ b/arch/arm/configs/tegra_defconfig
@@ -286,7 +286,7 @@ CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/arm/configs/u300_defconfig b/arch/arm/configs/u300_defconfig
index 36d77406e31b..c4e9fe4529dd 100644
--- a/arch/arm/configs/u300_defconfig
+++ b/arch/arm/configs/u300_defconfig
@@ -62,7 +62,7 @@ CONFIG_VFAT_FS=y
 CONFIG_TMPFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_FS=y
 # CONFIG_SCHED_DEBUG is not set
diff --git a/arch/arm/configs/u8500_defconfig b/arch/arm/configs/u8500_defconfig
index e2151a7aaf49..0566e2732b86 100644
--- a/arch/arm/configs/u8500_defconfig
+++ b/arch/arm/configs/u8500_defconfig
@@ -127,7 +127,7 @@ CONFIG_NFS_FS=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/arm/configs/vt8500_v6_v7_defconfig b/arch/arm/configs/vt8500_v6_v7_defconfig
index 1bfaa7bfc392..d5a2cc807940 100644
--- a/arch/arm/configs/vt8500_v6_v7_defconfig
+++ b/arch/arm/configs/vt8500_v6_v7_defconfig
@@ -84,6 +84,6 @@ CONFIG_NFS_FS=y
 CONFIG_NFS_V3_ACL=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_KERNEL=y
 CONFIG_LOCKUP_DETECTOR=y
diff --git a/arch/arm/configs/xcep_defconfig b/arch/arm/configs/xcep_defconfig
index 2eda24635e65..0b25bff6b928 100644
--- a/arch/arm/configs/xcep_defconfig
+++ b/arch/arm/configs/xcep_defconfig
@@ -79,7 +79,7 @@ CONFIG_NFS_V3=y
 CONFIG_NLS=m
 CONFIG_NLS_DEFAULT="utf8"
 CONFIG_NLS_UTF8=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_SCHED_DEBUG is not set
diff --git a/arch/arm/configs/zx_defconfig b/arch/arm/configs/zx_defconfig
index dfc061d87d2f..fe4fae21ccfa 100644
--- a/arch/arm/configs/zx_defconfig
+++ b/arch/arm/configs/zx_defconfig
@@ -95,7 +95,7 @@ CONFIG_TMPFS_POSIX_ACL=y
 CONFIG_NLS_CODEPAGE_936=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DEBUG_INFO=y
diff --git a/arch/arm64/configs/defconfig b/arch/arm64/configs/defconfig
index 6c7d147eed54..351968d0af49 100644
--- a/arch/arm64/configs/defconfig
+++ b/arch/arm64/configs/defconfig
@@ -548,7 +548,7 @@ CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_VIRTUALIZATION=y
 CONFIG_KVM=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/m68k/configs/amcore_defconfig b/arch/m68k/configs/amcore_defconfig
index 131b4101ae5d..8866b5d622ba 100644
--- a/arch/m68k/configs/amcore_defconfig
+++ b/arch/m68k/configs/amcore_defconfig
@@ -107,7 +107,7 @@ CONFIG_JFFS2_FS=y
 CONFIG_ROMFS_FS=y
 CONFIG_ROMFS_BACKED_BY_BOTH=y
 # CONFIG_NETWORK_FILESYSTEMS is not set
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
 # CONFIG_SECTION_MISMATCH_WARN_ONLY is not set
diff --git a/arch/mips/configs/ath25_defconfig b/arch/mips/configs/ath25_defconfig
index 2c829950be17..8d488cfd5e66 100644
--- a/arch/mips/configs/ath25_defconfig
+++ b/arch/mips/configs/ath25_defconfig
@@ -105,7 +105,7 @@ CONFIG_SQUASHFS_FILE_DIRECT=y
 CONFIG_SQUASHFS_DECOMP_MULTI_PERCPU=y
 # CONFIG_SQUASHFS_ZLIB is not set
 CONFIG_SQUASHFS_XZ=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/mips/configs/bcm47xx_defconfig b/arch/mips/configs/bcm47xx_defconfig
index fad8e964f14c..e4a29db1c416 100644
--- a/arch/mips/configs/bcm47xx_defconfig
+++ b/arch/mips/configs/bcm47xx_defconfig
@@ -74,7 +74,7 @@ CONFIG_USB_HCD_BCMA=y
 CONFIG_USB_HCD_SSB=y
 CONFIG_LEDS_TRIGGER_TIMER=y
 CONFIG_LEDS_TRIGGER_DEFAULT_ON=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_INFO_REDUCED=y
 CONFIG_STRIP_ASM_SYMS=y
diff --git a/arch/mips/configs/bmips_be_defconfig b/arch/mips/configs/bmips_be_defconfig
index a7072a14d396..8133a2809fd6 100644
--- a/arch/mips/configs/bmips_be_defconfig
+++ b/arch/mips/configs/bmips_be_defconfig
@@ -32,7 +32,7 @@ CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 # CONFIG_STANDALONE is not set
 # CONFIG_PREVENT_FIRMWARE_BUILD is not set
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_BRCMSTB_GISB_ARB=y
 CONFIG_MTD=y
 CONFIG_MTD_BCM63XX_PARTS=y
diff --git a/arch/mips/configs/bmips_stb_defconfig b/arch/mips/configs/bmips_stb_defconfig
index 3cefa6bc01dd..44269214aa88 100644
--- a/arch/mips/configs/bmips_stb_defconfig
+++ b/arch/mips/configs/bmips_stb_defconfig
@@ -85,7 +85,7 @@ CONFIG_CIFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_CMDLINE_BOOL=y
diff --git a/arch/mips/configs/ci20_defconfig b/arch/mips/configs/ci20_defconfig
index b42cfa7865f9..f7fbcec8c03a 100644
--- a/arch/mips/configs/ci20_defconfig
+++ b/arch/mips/configs/ci20_defconfig
@@ -147,7 +147,7 @@ CONFIG_NLS_ISO8859_15=y
 CONFIG_NLS_KOI8_R=y
 CONFIG_NLS_KOI8_U=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/mips/configs/generic_defconfig b/arch/mips/configs/generic_defconfig
index 91aacf2ef26d..b077a49e4a41 100644
--- a/arch/mips/configs/generic_defconfig
+++ b/arch/mips/configs/generic_defconfig
@@ -83,7 +83,7 @@ CONFIG_NFS_V4=y
 CONFIG_NFS_V4_1=y
 CONFIG_NFS_V4_2=y
 CONFIG_ROOT_NFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_INFO_REDUCED=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/mips/configs/lemote2f_defconfig b/arch/mips/configs/lemote2f_defconfig
index 1ec8ed8d05d1..ce702017e3d4 100644
--- a/arch/mips/configs/lemote2f_defconfig
+++ b/arch/mips/configs/lemote2f_defconfig
@@ -394,7 +394,7 @@ CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_FRAME_WARN=1024
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/mips/configs/loongson3_defconfig b/arch/mips/configs/loongson3_defconfig
index 324dfee23dfb..770ba1bb6eab 100644
--- a/arch/mips/configs/loongson3_defconfig
+++ b/arch/mips/configs/loongson3_defconfig
@@ -327,7 +327,7 @@ CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_CODEPAGE_936=y
 CONFIG_NLS_ASCII=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_FRAME_WARN=1024
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/mips/configs/nlm_xlp_defconfig b/arch/mips/configs/nlm_xlp_defconfig
index 5720ce23e9aa..8419baf8e993 100644
--- a/arch/mips/configs/nlm_xlp_defconfig
+++ b/arch/mips/configs/nlm_xlp_defconfig
@@ -549,7 +549,7 @@ CONFIG_NLS_ISO8859_14=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_FRAME_WARN=1024
diff --git a/arch/mips/configs/nlm_xlr_defconfig b/arch/mips/configs/nlm_xlr_defconfig
index fea56c535d92..e52af0b225ec 100644
--- a/arch/mips/configs/nlm_xlr_defconfig
+++ b/arch/mips/configs/nlm_xlr_defconfig
@@ -506,7 +506,7 @@ CONFIG_NLS_ISO8859_14=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_UNUSED_SYMBOLS=y
diff --git a/arch/mips/configs/pistachio_defconfig b/arch/mips/configs/pistachio_defconfig
index 7d32fbbca962..03fe8e9c08bb 100644
--- a/arch/mips/configs/pistachio_defconfig
+++ b/arch/mips/configs/pistachio_defconfig
@@ -297,7 +297,7 @@ CONFIG_NLS_DEFAULT="utf8"
 CONFIG_NLS_CODEPAGE_437=m
 CONFIG_NLS_ASCII=m
 CONFIG_NLS_ISO8859_1=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE=0
diff --git a/arch/mips/configs/qi_lb60_defconfig b/arch/mips/configs/qi_lb60_defconfig
index 3f1333517405..4f1a9c550157 100644
--- a/arch/mips/configs/qi_lb60_defconfig
+++ b/arch/mips/configs/qi_lb60_defconfig
@@ -170,7 +170,7 @@ CONFIG_NLS_ISO8859_15=y
 CONFIG_NLS_KOI8_R=y
 CONFIG_NLS_KOI8_U=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_READABLE_ASM=y
diff --git a/arch/mips/configs/rt305x_defconfig b/arch/mips/configs/rt305x_defconfig
index c695b7b1c4ae..2d82dd8a0d65 100644
--- a/arch/mips/configs/rt305x_defconfig
+++ b/arch/mips/configs/rt305x_defconfig
@@ -143,7 +143,7 @@ CONFIG_JFFS2_COMPRESSION_OPTIONS=y
 CONFIG_SQUASHFS=y
 # CONFIG_SQUASHFS_ZLIB is not set
 CONFIG_SQUASHFS_XZ=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_STRIP_ASM_SYMS=y
diff --git a/arch/mips/configs/xway_defconfig b/arch/mips/configs/xway_defconfig
index 4365108bef77..a8dbf51d2dd2 100644
--- a/arch/mips/configs/xway_defconfig
+++ b/arch/mips/configs/xway_defconfig
@@ -151,7 +151,7 @@ CONFIG_JFFS2_COMPRESSION_OPTIONS=y
 CONFIG_SQUASHFS=y
 # CONFIG_SQUASHFS_ZLIB is not set
 CONFIG_SQUASHFS_XZ=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/parisc/configs/generic-64bit_defconfig b/arch/parisc/configs/generic-64bit_defconfig
index c564e6e1fa23..06d6c12d2bae 100644
--- a/arch/parisc/configs/generic-64bit_defconfig
+++ b/arch/parisc/configs/generic-64bit_defconfig
@@ -279,7 +279,7 @@ CONFIG_NLS_ASCII=m
 CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_2=m
 CONFIG_NLS_UTF8=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_STRIP_ASM_SYMS=y
 CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/powerpc/configs/40x/virtex_defconfig b/arch/powerpc/configs/40x/virtex_defconfig
index 65dc084a154c..97619a504281 100644
--- a/arch/powerpc/configs/40x/virtex_defconfig
+++ b/arch/powerpc/configs/40x/virtex_defconfig
@@ -71,7 +71,7 @@ CONFIG_CRC_CCITT=y
 CONFIG_FONTS=y
 CONFIG_FONT_8x8=y
 CONFIG_FONT_8x16=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_CRYPTO_ANSI_CPRNG is not set
diff --git a/arch/powerpc/configs/44x/fsp2_defconfig b/arch/powerpc/configs/44x/fsp2_defconfig
index e8e6a6999852..204af7941cc9 100644
--- a/arch/powerpc/configs/44x/fsp2_defconfig
+++ b/arch/powerpc/configs/44x/fsp2_defconfig
@@ -111,7 +111,7 @@ CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_DEFAULT="n"
 CONFIG_XZ_DEC=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MESSAGE_LOGLEVEL_DEFAULT=3
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
diff --git a/arch/powerpc/configs/44x/virtex5_defconfig b/arch/powerpc/configs/44x/virtex5_defconfig
index ce052064bcbb..5e843f38f170 100644
--- a/arch/powerpc/configs/44x/virtex5_defconfig
+++ b/arch/powerpc/configs/44x/virtex5_defconfig
@@ -70,7 +70,7 @@ CONFIG_CRC_CCITT=y
 CONFIG_FONTS=y
 CONFIG_FONT_8x8=y
 CONFIG_FONT_8x16=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_KERNEL=y
 # CONFIG_CRYPTO_ANSI_CPRNG is not set
diff --git a/arch/powerpc/configs/44x/warp_defconfig b/arch/powerpc/configs/44x/warp_defconfig
index ab932488e68b..0bc1951a2dda 100644
--- a/arch/powerpc/configs/44x/warp_defconfig
+++ b/arch/powerpc/configs/44x/warp_defconfig
@@ -90,7 +90,7 @@ CONFIG_NLS_ISO8859_15=y
 CONFIG_NLS_UTF8=y
 CONFIG_CRC_CCITT=y
 CONFIG_CRC_T10DIF=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/powerpc/configs/52xx/cm5200_defconfig b/arch/powerpc/configs/52xx/cm5200_defconfig
index c1faac800806..87374742d175 100644
--- a/arch/powerpc/configs/52xx/cm5200_defconfig
+++ b/arch/powerpc/configs/52xx/cm5200_defconfig
@@ -72,7 +72,7 @@ CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DETECT_HUNG_TASK=y
 # CONFIG_DEBUG_BUGVERBOSE is not set
 CONFIG_CRYPTO_ECB=y
diff --git a/arch/powerpc/configs/52xx/lite5200b_defconfig b/arch/powerpc/configs/52xx/lite5200b_defconfig
index 9493b02ac660..4f9a8a38c601 100644
--- a/arch/powerpc/configs/52xx/lite5200b_defconfig
+++ b/arch/powerpc/configs/52xx/lite5200b_defconfig
@@ -58,7 +58,7 @@ CONFIG_TMPFS=y
 CONFIG_NFS_FS=y
 CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DETECT_HUNG_TASK=y
 # CONFIG_DEBUG_BUGVERBOSE is not set
diff --git a/arch/powerpc/configs/52xx/motionpro_defconfig b/arch/powerpc/configs/52xx/motionpro_defconfig
index fe8126bc1655..f6ce4414e812 100644
--- a/arch/powerpc/configs/52xx/motionpro_defconfig
+++ b/arch/powerpc/configs/52xx/motionpro_defconfig
@@ -84,7 +84,7 @@ CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DETECT_HUNG_TASK=y
 # CONFIG_DEBUG_BUGVERBOSE is not set
diff --git a/arch/powerpc/configs/52xx/tqm5200_defconfig b/arch/powerpc/configs/52xx/tqm5200_defconfig
index b8b316b884aa..b9fa1bb55560 100644
--- a/arch/powerpc/configs/52xx/tqm5200_defconfig
+++ b/arch/powerpc/configs/52xx/tqm5200_defconfig
@@ -86,7 +86,7 @@ CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DETECT_HUNG_TASK=y
 # CONFIG_DEBUG_BUGVERBOSE is not set
diff --git a/arch/powerpc/configs/gamecube_defconfig b/arch/powerpc/configs/gamecube_defconfig
index c0eec4a5df4e..de0c808c17c1 100644
--- a/arch/powerpc/configs/gamecube_defconfig
+++ b/arch/powerpc/configs/gamecube_defconfig
@@ -89,7 +89,7 @@ CONFIG_CIFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_CRC_CCITT=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_SPINLOCK=y
 CONFIG_DEBUG_MUTEXES=y
 CONFIG_LATENCYTOP=y
diff --git a/arch/powerpc/configs/mpc5200_defconfig b/arch/powerpc/configs/mpc5200_defconfig
index 88336d0df0d6..bd407cc11ebd 100644
--- a/arch/powerpc/configs/mpc5200_defconfig
+++ b/arch/powerpc/configs/mpc5200_defconfig
@@ -126,7 +126,7 @@ CONFIG_NFS_V4=y
 CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DETECT_HUNG_TASK=y
diff --git a/arch/powerpc/configs/pasemi_defconfig b/arch/powerpc/configs/pasemi_defconfig
index fe43ff47bd2f..6471b5f02125 100644
--- a/arch/powerpc/configs/pasemi_defconfig
+++ b/arch/powerpc/configs/pasemi_defconfig
@@ -166,7 +166,7 @@ CONFIG_NFSD_V4=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_CRC_CCITT=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_FS=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
diff --git a/arch/powerpc/configs/wii_defconfig b/arch/powerpc/configs/wii_defconfig
index dcdd51b57783..f06d394d7153 100644
--- a/arch/powerpc/configs/wii_defconfig
+++ b/arch/powerpc/configs/wii_defconfig
@@ -110,7 +110,7 @@ CONFIG_CIFS=m
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_CRC_CCITT=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_SPINLOCK=y
 CONFIG_DEBUG_MUTEXES=y
diff --git a/arch/s390/configs/default_defconfig b/arch/s390/configs/default_defconfig
index 282072206df7..d60240703b87 100644
--- a/arch/s390/configs/default_defconfig
+++ b/arch/s390/configs/default_defconfig
@@ -564,7 +564,7 @@ CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
 CONFIG_DLM=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_INFO_DWARF4=y
diff --git a/arch/s390/configs/gcov_defconfig b/arch/s390/configs/gcov_defconfig
index 3c6b78189fbc..f646d908cc16 100644
--- a/arch/s390/configs/gcov_defconfig
+++ b/arch/s390/configs/gcov_defconfig
@@ -558,7 +558,7 @@ CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
 CONFIG_DLM=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_INFO_DWARF4=y
 CONFIG_GDB_SCRIPTS=y
diff --git a/arch/s390/configs/performance_defconfig b/arch/s390/configs/performance_defconfig
index 653d72bcc007..bd5cd53ad6fe 100644
--- a/arch/s390/configs/performance_defconfig
+++ b/arch/s390/configs/performance_defconfig
@@ -556,7 +556,7 @@ CONFIG_NLS_ISO8859_1=m
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
 CONFIG_DLM=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_INFO_DWARF4=y
 CONFIG_GDB_SCRIPTS=y
diff --git a/arch/s390/configs/zfcpdump_defconfig b/arch/s390/configs/zfcpdump_defconfig
index afa46a7406ea..64fa6b10dbc1 100644
--- a/arch/s390/configs/zfcpdump_defconfig
+++ b/arch/s390/configs/zfcpdump_defconfig
@@ -57,7 +57,7 @@ CONFIG_RAW_DRIVER=y
 CONFIG_CONFIGFS_FS=y
 # CONFIG_MISC_FILESYSTEMS is not set
 # CONFIG_NETWORK_FILESYSTEMS is not set
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DEBUG_INFO=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_PANIC_ON_OOPS=y
diff --git a/arch/sh/configs/edosk7760_defconfig b/arch/sh/configs/edosk7760_defconfig
index e1077a041ac3..e588da2ba566 100644
--- a/arch/sh/configs/edosk7760_defconfig
+++ b/arch/sh/configs/edosk7760_defconfig
@@ -109,7 +109,7 @@ CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_ISO8859_15=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_UNUSED_SYMBOLS=y
diff --git a/arch/sh/configs/sdk7786_defconfig b/arch/sh/configs/sdk7786_defconfig
index 36642ec2cb97..280695c64d3e 100644
--- a/arch/sh/configs/sdk7786_defconfig
+++ b/arch/sh/configs/sdk7786_defconfig
@@ -215,7 +215,7 @@ CONFIG_NLS_ASCII=m
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_UTF8=m
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/sh/configs/se7722_defconfig b/arch/sh/configs/se7722_defconfig
index ae998c7e2ee0..09aac57eddb7 100644
--- a/arch/sh/configs/se7722_defconfig
+++ b/arch/sh/configs/se7722_defconfig
@@ -53,7 +53,7 @@ CONFIG_EXT3_FS=y
 CONFIG_PROC_KCORE=y
 CONFIG_TMPFS=y
 CONFIG_HUGETLBFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_FS=y
diff --git a/arch/sh/configs/sh7785lcr_32bit_defconfig b/arch/sh/configs/sh7785lcr_32bit_defconfig
index 2fce54d9c388..977b6174ece0 100644
--- a/arch/sh/configs/sh7785lcr_32bit_defconfig
+++ b/arch/sh/configs/sh7785lcr_32bit_defconfig
@@ -144,7 +144,7 @@ CONFIG_NFSD_V3=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_CODEPAGE_932=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
diff --git a/arch/sh/configs/urquell_defconfig b/arch/sh/configs/urquell_defconfig
index 01c9a91ee896..79723309fcfa 100644
--- a/arch/sh/configs/urquell_defconfig
+++ b/arch/sh/configs/urquell_defconfig
@@ -142,7 +142,7 @@ CONFIG_ROOT_NFS=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_CODEPAGE_932=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_DEBUG_FS=y
diff --git a/arch/sparc/configs/sparc64_defconfig b/arch/sparc/configs/sparc64_defconfig
index b2e650d1764f..5cb77afd6d20 100644
--- a/arch/sparc/configs/sparc64_defconfig
+++ b/arch/sparc/configs/sparc64_defconfig
@@ -202,7 +202,7 @@ CONFIG_EXT3_FS_SECURITY=y
 CONFIG_PROC_KCORE=y
 CONFIG_TMPFS=y
 CONFIG_HUGETLBFS=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
diff --git a/arch/x86/configs/i386_defconfig b/arch/x86/configs/i386_defconfig
index 6cf79e1a6830..9752adff0949 100644
--- a/arch/x86/configs/i386_defconfig
+++ b/arch/x86/configs/i386_defconfig
@@ -287,7 +287,7 @@ CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 CONFIG_FRAME_WARN=1024
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/x86/configs/x86_64_defconfig b/arch/x86/configs/x86_64_defconfig
index de45f57b410d..7be6f8538cbc 100644
--- a/arch/x86/configs/x86_64_defconfig
+++ b/arch/x86/configs/x86_64_defconfig
@@ -286,7 +286,7 @@ CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ASCII=y
 CONFIG_NLS_ISO8859_1=y
 CONFIG_NLS_UTF8=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 # CONFIG_ENABLE_WARN_DEPRECATED is not set
 CONFIG_MAGIC_SYSRQ=y
 # CONFIG_UNUSED_SYMBOLS is not set
diff --git a/arch/xtensa/configs/audio_kc705_defconfig b/arch/xtensa/configs/audio_kc705_defconfig
index 8d16925765cb..92eb1351e23a 100644
--- a/arch/xtensa/configs/audio_kc705_defconfig
+++ b/arch/xtensa/configs/audio_kc705_defconfig
@@ -123,7 +123,7 @@ CONFIG_ROOT_NFS=y
 CONFIG_SUNRPC_DEBUG=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/xtensa/configs/cadence_csp_defconfig b/arch/xtensa/configs/cadence_csp_defconfig
index f2d3094aa1d1..69aadc4a7c11 100644
--- a/arch/xtensa/configs/cadence_csp_defconfig
+++ b/arch/xtensa/configs/cadence_csp_defconfig
@@ -102,7 +102,7 @@ CONFIG_ROOT_NFS=y
 CONFIG_SUNRPC_DEBUG=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/xtensa/configs/generic_kc705_defconfig b/arch/xtensa/configs/generic_kc705_defconfig
index 744adeaf2945..1d1b4e8a2004 100644
--- a/arch/xtensa/configs/generic_kc705_defconfig
+++ b/arch/xtensa/configs/generic_kc705_defconfig
@@ -110,7 +110,7 @@ CONFIG_ROOT_NFS=y
 CONFIG_SUNRPC_DEBUG=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/arch/xtensa/configs/nommu_kc705_defconfig b/arch/xtensa/configs/nommu_kc705_defconfig
index 78c2529d0459..09dfc089d7df 100644
--- a/arch/xtensa/configs/nommu_kc705_defconfig
+++ b/arch/xtensa/configs/nommu_kc705_defconfig
@@ -107,7 +107,7 @@ CONFIG_ROOT_NFS=y
 CONFIG_SUNRPC_DEBUG=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 # CONFIG_FRAME_POINTER is not set
diff --git a/arch/xtensa/configs/smp_lx200_defconfig b/arch/xtensa/configs/smp_lx200_defconfig
index 14e3ca353ac8..3b4e87f24e75 100644
--- a/arch/xtensa/configs/smp_lx200_defconfig
+++ b/arch/xtensa/configs/smp_lx200_defconfig
@@ -114,7 +114,7 @@ CONFIG_ROOT_NFS=y
 CONFIG_SUNRPC_DEBUG=y
 CONFIG_NLS_CODEPAGE_437=y
 CONFIG_NLS_ISO8859_1=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 CONFIG_MAGIC_SYSRQ=y
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index fc47863f629c..26cf6cadd267 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1202,8 +1202,40 @@ static inline void boot_delay_msec(int level)
 }
 #endif
 
-static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
-module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
+static int printk_time = CONFIG_PRINTK_TIME;
+
+static int printk_time_set(const char *val, const struct kernel_param *kp)
+{
+	char *param = strstrip((char *)val);
+
+	if (strlen(param) != 1)
+		return -EINVAL;
+
+	if (!strncmp("0", param, 1) || !strncmp("n", param, 1) ||
+	    !strncmp("N", param, 1)) {
+		printk_time = 0;
+	} else if (!strncmp("1", param, 1) || !strncmp("y", param, 1) ||
+		   !strncmp("Y", param, 1)) {
+		printk_time = 1;
+	} else {
+		pr_warn("printk: invalid timestamp value %s.\n", param);
+		return -EINVAL;
+	}
+
+	pr_info("printk: timestamp set to %d.\n", printk_time);
+	return 0;
+}
+
+static int printk_time_get(char *buffer, const struct kernel_param *kp)
+{
+	return scnprintf(buffer, PAGE_SIZE, "%d", printk_time);
+}
+
+static struct kernel_param_ops printk_time_ops = {
+	.set = printk_time_set,
+	.get = printk_time_get,
+};
+module_param_cb(time, &printk_time_ops, NULL, S_IRUGO | S_IWUSR);
 
 static size_t print_time(u64 ts, char *buf)
 {
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 98fe715522e8..5b1662ec546f 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1,7 +1,9 @@
 menu "printk and dmesg options"
 
 config PRINTK_TIME
-	bool "Show timing information on printks"
+	int "Show timing information on printks (0-1)"
+	range 0 1
+	default "0"
 	depends on PRINTK
 	help
 	  Selecting this option causes time stamps of the printk()
@@ -10,7 +12,8 @@ config PRINTK_TIME
 
 	  The timestamp is always recorded internally, and exported
 	  to /dev/kmsg. This flag just specifies if the timestamp should
-	  be included, not that the timestamp is recorded.
+	  be included, not that the timestamp is recorded. 0 disables the
+	  timestamp and 1 uses the local clock.
 
 	  The behavior is also controlled by the kernel command line
 	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
diff --git a/tools/testing/selftests/rcutorture/configs/lock/CFcommon b/tools/testing/selftests/rcutorture/configs/lock/CFcommon
index e372dc269254..779f984fb25c 100644
--- a/tools/testing/selftests/rcutorture/configs/lock/CFcommon
+++ b/tools/testing/selftests/rcutorture/configs/lock/CFcommon
@@ -1,2 +1,2 @@
 CONFIG_LOCK_TORTURE_TEST=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/CFcommon b/tools/testing/selftests/rcutorture/configs/rcu/CFcommon
index d2d2a86139db..784fd5d724dd 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/CFcommon
+++ b/tools/testing/selftests/rcutorture/configs/rcu/CFcommon
@@ -1,2 +1,2 @@
 CONFIG_RCU_TORTURE_TEST=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
diff --git a/tools/testing/selftests/rcutorture/configs/rcuperf/CFcommon b/tools/testing/selftests/rcutorture/configs/rcuperf/CFcommon
index a09816b8c0f3..edd5a7bf4b12 100644
--- a/tools/testing/selftests/rcutorture/configs/rcuperf/CFcommon
+++ b/tools/testing/selftests/rcutorture/configs/rcuperf/CFcommon
@@ -1,2 +1,2 @@
 CONFIG_RCU_PERF_TEST=y
-CONFIG_PRINTK_TIME=y
+CONFIG_PRINTK_TIME=1
-- 
1.8.5.5

Re: [PATCH 1/2] printk: Make CONFIG_PRINTK_TIME an int

[Luis R. Rodriguez]

On Tue, Jul 25, 2017 at 08:17:26AM -0400, Prarit Bhargava wrote:
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index fc47863f629c..26cf6cadd267 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -1202,8 +1202,40 @@ static inline void boot_delay_msec(int level)
>  }
>  #endif
>  
> -static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
> -module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
> +static int printk_time = CONFIG_PRINTK_TIME;

You could just use unsigned int but is the reason you went with int to
enable backward compatibility with the old bool =y or =n?

  Luis

Re: [PATCH 1/2] printk: Make CONFIG_PRINTK_TIME an int

[Prarit Bhargava]

On 07/25/2017 08:55 AM, Luis R. Rodriguez wrote:
> On Tue, Jul 25, 2017 at 08:17:26AM -0400, Prarit Bhargava wrote:
>> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
>> index fc47863f629c..26cf6cadd267 100644
>> --- a/kernel/printk/printk.c
>> +++ b/kernel/printk/printk.c
>> @@ -1202,8 +1202,40 @@ static inline void boot_delay_msec(int level)
>>  }
>>  #endif
>>  
>> -static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
>> -module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
>> +static int printk_time = CONFIG_PRINTK_TIME;
> 
> You could just use unsigned int but is the reason you went with int to
> enable backward compatibility with the old bool =y or =n?

Yes, I wanted to preserve backwards compatibility.

P.

[PATCH 2/2] printk: Add boottime and real timestamps

[Prarit Bhargava]

printk.time=1/CONFIG_PRINTK_TIME=Y timestamps printks with an unmodified
hardware clock timestamp.  This clock loses time each day making it
difficult to determine when an issue has occurred in the kernel log.

Modify printk.time to output local, monotonic, or a real timestamp.
Modify the output of /sys/module/printk/parameters/time to output the type
of clock so userspace programs can interpret the timestamp.

Real clock & 32-bit systems:  Selecting the real clock printk timestamp
may lead to unlikely situations where a timestamp is wrong because the
real time offset is read without the protection of a sequence lock in the
call to ktime_get_log_ts() in printk_get_ts().

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Christoffer Dall <cdall@linaro.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-doc@vger.kernel.org


---
 Documentation/admin-guide/kernel-parameters.txt |  6 +-
 include/linux/timekeeping.h                     |  1 +
 kernel/printk/printk.c                          | 77 +++++++++++++++++++++----
 kernel/time/timekeeping.c                       | 14 +++++
 lib/Kconfig.debug                               |  7 ++-
 5 files changed, 89 insertions(+), 16 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c3b14abf9da4..c03240d057b1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3188,8 +3188,10 @@
 			ratelimit - ratelimit the logging
 			Default: ratelimit
 
-	printk.time=	Show timing data prefixed to each printk message line
-			Format: <string>  (1/Y/y=enable, 0/N/n=disable)
+	printk.time=	Show timestamp prefixed to each printk message line
+			Format: <string>
+				(0/N/n = disable, 1/Y/y = local/unadjusted HW,
+				 2 = monotonic, 3 = real)
 
 	processor.max_cstate=	[HW,ACPI]
 			Limit processor to maximum C-state
diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
index ddc229ff6d1e..adb84af42deb 100644
--- a/include/linux/timekeeping.h
+++ b/include/linux/timekeeping.h
@@ -239,6 +239,7 @@ static inline u64 ktime_get_raw_ns(void)
 extern u64 ktime_get_mono_fast_ns(void);
 extern u64 ktime_get_raw_fast_ns(void);
 extern u64 ktime_get_boot_fast_ns(void);
+extern u64 ktime_get_log_ts(u64 *offset_real);
 
 /*
  * Timespec interfaces utilizing the ktime based ones
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 26cf6cadd267..35536369a56d 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -576,6 +576,8 @@ static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len,
 	return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len);
 }
 
+static u64 printk_get_ts(void);
+
 /* insert record into the buffer, discard old ones, update heads */
 static int log_store(int facility, int level,
 		     enum log_flags flags, u64 ts_nsec,
@@ -624,7 +626,7 @@ static int log_store(int facility, int level,
 	if (ts_nsec > 0)
 		msg->ts_nsec = ts_nsec;
 	else
-		msg->ts_nsec = local_clock();
+		msg->ts_nsec = printk_get_ts();
 	memset(log_dict(msg) + dict_len, 0, pad_len);
 	msg->len = size;
 
@@ -1203,26 +1205,60 @@ static inline void boot_delay_msec(int level)
 #endif
 
 static int printk_time = CONFIG_PRINTK_TIME;
+static int printk_time_setting; /* initial setting */
 
+/*
+ * Real clock & 32-bit systems:  Selecting the real clock printk timestamp may
+ * lead to unlikely situations where a timestamp is wrong because the real time
+ * offset is read without the protection of a sequence lock in the call to
+ * ktime_get_log_ts() in printk_get_ts() below.
+ */
 static int printk_time_set(const char *val, const struct kernel_param *kp)
 {
 	char *param = strstrip((char *)val);
+	int _printk_time;
 
 	if (strlen(param) != 1)
 		return -EINVAL;
 
-	if (!strncmp("0", param, 1) || !strncmp("n", param, 1) ||
-	    !strncmp("N", param, 1)) {
-		printk_time = 0;
-	} else if (!strncmp("1", param, 1) || !strncmp("y", param, 1) ||
-		   !strncmp("Y", param, 1)) {
-		printk_time = 1;
-	} else {
-		pr_warn("printk: invalid timestamp value %s.\n", param);
+	switch (param[0]) {
+	case '0':
+	case 'n':
+	case 'N':
+		_printk_time = 0; /* none/disabled */
+		break;
+	case '1':
+	case 'y':
+	case 'Y':
+		_printk_time = 1; /* local unadjusted HW clock */
+		break;
+	case '2':
+		_printk_time = 2; /* boot time */
+		break;
+	case '3':
+		_printk_time = 3; /* real time */
+		break;
+	default:
+		pr_warn("printk: invalid timestamp value\n");
+		return -EINVAL;
+	}
+
+	/*
+	 * Only allow enabling and disabling of the current printk_time
+	 * setting.  Changing it from one setting to another confuses
+	 * userspace.
+	 */
+	if (printk_time_setting == 0) {
+		printk_time_setting = _printk_time;
+	} else if ((printk_time_setting != _printk_time) &&
+		   (_printk_time != 0)) {
+		pr_warn("printk: timestamp can only be set to 0 or %d ",
+			printk_time_setting);
 		return -EINVAL;
 	}
 
-	pr_info("printk: timestamp set to %d.\n", printk_time);
+	printk_time = _printk_time;
+	pr_info("printk: timestamp set to %d.", printk_time);
 	return 0;
 }
 
@@ -1237,6 +1273,21 @@ static int printk_time_get(char *buffer, const struct kernel_param *kp)
 };
 module_param_cb(time, &printk_time_ops, NULL, S_IRUGO | S_IWUSR);
 
+static u64 printk_get_ts(void)
+{
+	u64 mono, offset_real;
+
+	if (printk_time <= 1)
+		return local_clock();
+
+	mono = ktime_get_log_ts(&offset_real);
+
+	if (printk_time == 2)
+		return mono;
+
+	return mono + offset_real;
+}
+
 static size_t print_time(u64 ts, char *buf)
 {
 	unsigned long rem_nsec;
@@ -1675,7 +1726,7 @@ static bool cont_add(int facility, int level, enum log_flags flags, const char *
 		cont.facility = facility;
 		cont.level = level;
 		cont.owner = current;
-		cont.ts_nsec = local_clock();
+		cont.ts_nsec = printk_get_ts();
 		cont.flags = flags;
 	}
 
@@ -2691,6 +2742,10 @@ static int __init printk_late_init(void)
 	struct console *con;
 	int ret;
 
+	/* initialize printk_time settings */
+	if (printk_time_setting == 0)
+		printk_time_setting = printk_time;
+
 	for_each_console(con) {
 		if (!keep_bootcon && con->flags & CON_BOOT) {
 			/*
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index cedafa008de5..96f06a16c51f 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -25,6 +25,7 @@
 #include <linux/stop_machine.h>
 #include <linux/pvclock_gtod.h>
 #include <linux/compiler.h>
+#include <linux/sched/clock.h>
 
 #include "tick-internal.h"
 #include "ntp_internal.h"
@@ -45,6 +46,7 @@
 
 static DEFINE_RAW_SPINLOCK(timekeeper_lock);
 static struct timekeeper shadow_timekeeper;
+static int timekeeping_active;
 
 /**
  * struct tk_fast - NMI safe timekeeper
@@ -477,6 +479,16 @@ u64 notrace ktime_get_boot_fast_ns(void)
 }
 EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
 
+u64 ktime_get_log_ts(u64 *offset_real)
+{
+	*offset_real = ktime_to_ns(tk_core.timekeeper.offs_real);
+
+	if (timekeeping_active)
+		return ktime_get_mono_fast_ns();
+	else
+		return local_clock();
+}
+
 /* Suspend-time cycles value for halted fast timekeeper. */
 static u64 cycles_at_suspend;
 
@@ -1530,6 +1542,8 @@ void __init timekeeping_init(void)
 
 	write_seqcount_end(&tk_core.seq);
 	raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
+
+	timekeeping_active = 1;
 }
 
 /* time in seconds when suspend began for persistent clock */
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 5b1662ec546f..6cd38a25f8ea 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1,8 +1,8 @@
 menu "printk and dmesg options"
 
 config PRINTK_TIME
-	int "Show timing information on printks (0-1)"
-	range 0 1
+	int "Show timing information on printks (0-3)"
+	range 0 3
 	default "0"
 	depends on PRINTK
 	help
@@ -13,7 +13,8 @@ config PRINTK_TIME
 	  The timestamp is always recorded internally, and exported
 	  to /dev/kmsg. This flag just specifies if the timestamp should
 	  be included, not that the timestamp is recorded. 0 disables the
-	  timestamp and 1 uses the local clock.
+	  timestamp and 1 uses the local clock, 2 uses the monotonic clock, and
+	  3 uses real clock.
 
 	  The behavior is also controlled by the kernel command line
 	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
-- 
1.8.5.5

Re: [PATCH 2/2] printk: Add boottime and real timestamps

[Peter Zijlstra]

On Tue, Jul 25, 2017 at 08:17:27AM -0400, Prarit Bhargava wrote:
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 5b1662ec546f..6cd38a25f8ea 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1,8 +1,8 @@
>  menu "printk and dmesg options"
>  
>  config PRINTK_TIME
> -	int "Show timing information on printks (0-1)"
> -	range 0 1
> +	int "Show timing information on printks (0-3)"
> +	range 0 3
>  	default "0"
>  	depends on PRINTK
>  	help
> @@ -13,7 +13,8 @@ config PRINTK_TIME
>  	  The timestamp is always recorded internally, and exported
>  	  to /dev/kmsg. This flag just specifies if the timestamp should
>  	  be included, not that the timestamp is recorded. 0 disables the
> -	  timestamp and 1 uses the local clock.
> +	  timestamp and 1 uses the local clock, 2 uses the monotonic clock, and
> +	  3 uses real clock.
>  
>  	  The behavior is also controlled by the kernel command line
>  	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst


choice
	prompt "printk default clock"
	default PRIMTK_TIME_DISABLE
	help
	 goes here

	config PRINTK_TIME_DISABLE
	bool "Disabled"
	help
	 goes here

	config PRINTK_TIME_LOCAL
	bool "local clock"
	help
	 goes here

	config PRINTK_TIME_MONO
	bool "CLOCK_MONOTONIC"
	help
	 goes here

	config PRINTK_TIME_REAL
	bool "CLOCK_REALTIME"
	help
	 goes here

endchoice

config PRINTK_TIME
	int
	default 0 if PRINTK_TIME_DISABLE
	default 1 if PRINTK_TIME_LOCAL
	default 2 if PRINTK_TIME_MONO
	default 3 if PRINTK_TIME_REAL


Although I must strongly discourage using REALTIME, DST will make
untangling your logs an absolute nightmare. I would simply not provide
it.

Re: [PATCH 2/2] printk: Add boottime and real timestamps

[Mark Salyzyn]

On 07/25/2017 06:00 AM, Peter Zijlstra wrote:
> On Tue, Jul 25, 2017 at 08:17:27AM -0400, Prarit Bhargava wrote:
>> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
>> index 5b1662ec546f..6cd38a25f8ea 100644
>> --- a/lib/Kconfig.debug
>> +++ b/lib/Kconfig.debug
>> @@ -1,8 +1,8 @@
>>   menu "printk and dmesg options"
>>   
>>   config PRINTK_TIME
>> -	int "Show timing information on printks (0-1)"
>> -	range 0 1
>> +	int "Show timing information on printks (0-3)"
>> +	range 0 3
>>   	default "0"
>>   	depends on PRINTK
>>   	help
>> @@ -13,7 +13,8 @@ config PRINTK_TIME
>>   	  The timestamp is always recorded internally, and exported
>>   	  to /dev/kmsg. This flag just specifies if the timestamp should
>>   	  be included, not that the timestamp is recorded. 0 disables the
>> -	  timestamp and 1 uses the local clock.
>> +	  timestamp and 1 uses the local clock, 2 uses the monotonic clock, and
>> +	  3 uses real clock.
>>   
>>   	  The behavior is also controlled by the kernel command line
>>   	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
>
> choice
> 	prompt "printk default clock"
> 	default PRIMTK_TIME_DISABLE
> 	help
> 	 goes here
>
> 	config PRINTK_TIME_DISABLE
> 	bool "Disabled"
> 	help
> 	 goes here
>
> 	config PRINTK_TIME_LOCAL
> 	bool "local clock"
> 	help
> 	 goes here
>
> 	config PRINTK_TIME_MONO
> 	bool "CLOCK_MONOTONIC"
> 	help
> 	 goes here
>
> 	config PRINTK_TIME_REAL
> 	bool "CLOCK_REALTIME"
> 	help
> 	 goes here
>
> endchoice
>
> config PRINTK_TIME
> 	int
> 	default 0 if PRINTK_TIME_DISABLE
> 	default 1 if PRINTK_TIME_LOCAL
> 	default 2 if PRINTK_TIME_MONO
> 	default 3 if PRINTK_TIME_REAL
>
>
> Although I must strongly discourage using REALTIME, DST will make
> untangling your logs an absolute nightmare. I would simply not provide
> it.

I agree with using select, ensures only valid values are landed. It does 
mean that CONFIG_PRINTK_TIME in-effect gets deprecated.

REALTIME is always UTC in the kernel.

What about BOOTTIME?

-- Mark

Re: [PATCH 2/2] printk: Add boottime and real timestamps

[Prarit Bhargava]

On 07/25/2017 09:00 AM, Peter Zijlstra wrote:
> On Tue, Jul 25, 2017 at 08:17:27AM -0400, Prarit Bhargava wrote:
>> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
>> index 5b1662ec546f..6cd38a25f8ea 100644
>> --- a/lib/Kconfig.debug
>> +++ b/lib/Kconfig.debug
>> @@ -1,8 +1,8 @@
>>  menu "printk and dmesg options"
>>  
>>  config PRINTK_TIME
>> -	int "Show timing information on printks (0-1)"
>> -	range 0 1
>> +	int "Show timing information on printks (0-3)"
>> +	range 0 3
>>  	default "0"
>>  	depends on PRINTK
>>  	help
>> @@ -13,7 +13,8 @@ config PRINTK_TIME
>>  	  The timestamp is always recorded internally, and exported
>>  	  to /dev/kmsg. This flag just specifies if the timestamp should
>>  	  be included, not that the timestamp is recorded. 0 disables the
>> -	  timestamp and 1 uses the local clock.
>> +	  timestamp and 1 uses the local clock, 2 uses the monotonic clock, and
>> +	  3 uses real clock.
>>  
>>  	  The behavior is also controlled by the kernel command line
>>  	  parameter printk.time=1. See Documentation/admin-guide/kernel-parameters.rst
> 
> 
> choice
> 	prompt "printk default clock"
> 	default PRIMTK_TIME_DISABLE
> 	help
> 	 goes here
> 
> 	config PRINTK_TIME_DISABLE
> 	bool "Disabled"
> 	help
> 	 goes here
> 
> 	config PRINTK_TIME_LOCAL
> 	bool "local clock"
> 	help
> 	 goes here
> 
> 	config PRINTK_TIME_MONO
> 	bool "CLOCK_MONOTONIC"
> 	help
> 	 goes here
> 
> 	config PRINTK_TIME_REAL
> 	bool "CLOCK_REALTIME"
> 	help
> 	 goes here
> 
> endchoice
> 
> config PRINTK_TIME
> 	int
> 	default 0 if PRINTK_TIME_DISABLE
> 	default 1 if PRINTK_TIME_LOCAL
> 	default 2 if PRINTK_TIME_MONO
> 	default 3 if PRINTK_TIME_REAL
> 
> 

Thanks for the above change.  I can see that makes the code simpler.

> Although I must strongly discourage using REALTIME, DST will make
> untangling your logs an absolute nightmare. I would simply not provide
> it.

I understand your concern, however, I've been in situations where REALTIME
stamping has pointed me in the direction of where a bug was.  Even with the
complicated logs I think it is worthwhile.

P.

Re: [PATCH 2/2] printk: Add boottime and real timestamps

[Thomas Gleixner]

On Fri, 28 Jul 2017, Prarit Bhargava wrote:
> On 07/25/2017 09:00 AM, Peter Zijlstra wrote:
> Thanks for the above change.  I can see that makes the code simpler.
> 
> > Although I must strongly discourage using REALTIME, DST will make
> > untangling your logs an absolute nightmare. I would simply not provide
> > it.
> 
> I understand your concern, however, I've been in situations where REALTIME
> stamping has pointed me in the direction of where a bug was.  Even with the
> complicated logs I think it is worthwhile.

As Mark pointed out. ktime_get_real() and the fast variant return UTC. The
timezone mess plus the DST nonsense are done in user space.

Thanks,

	tglx

Re: [PATCH 2/2] printk: Add boottime and real timestamps

[kbuild test robot]

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Hi Prarit,

[auto build test ERROR on linus/master]
[also build test ERROR on v4.13-rc2]
[cannot apply to next-20170726]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Prarit-Bhargava/printk-allow-different-timestamps-for-printk-time/20170727-104148
config: i386-tinyconfig (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   kernel/printk/printk.c: In function 'printk_late_init':
>> kernel/printk/printk.c:2746:6: error: 'printk_time_setting' undeclared (first use in this function)
     if (printk_time_setting == 0)
         ^~~~~~~~~~~~~~~~~~~
   kernel/printk/printk.c:2746:6: note: each undeclared identifier is reported only once for each function it appears in
>> kernel/printk/printk.c:2747:25: error: 'printk_time' undeclared (first use in this function)
      printk_time_setting = printk_time;
                            ^~~~~~~~~~~

vim +/printk_time_setting +2746 kernel/printk/printk.c

  2724	
  2725	/*
  2726	 * Some boot consoles access data that is in the init section and which will
  2727	 * be discarded after the initcalls have been run. To make sure that no code
  2728	 * will access this data, unregister the boot consoles in a late initcall.
  2729	 *
  2730	 * If for some reason, such as deferred probe or the driver being a loadable
  2731	 * module, the real console hasn't registered yet at this point, there will
  2732	 * be a brief interval in which no messages are logged to the console, which
  2733	 * makes it difficult to diagnose problems that occur during this time.
  2734	 *
  2735	 * To mitigate this problem somewhat, only unregister consoles whose memory
  2736	 * intersects with the init section. Note that code exists elsewhere to get
  2737	 * rid of the boot console as soon as the proper console shows up, so there
  2738	 * won't be side-effects from postponing the removal.
  2739	 */
  2740	static int __init printk_late_init(void)
  2741	{
  2742		struct console *con;
  2743		int ret;
  2744	
  2745		/* initialize printk_time settings */
> 2746		if (printk_time_setting == 0)
> 2747			printk_time_setting = printk_time;
  2748	
  2749		for_each_console(con) {
  2750			if (!keep_bootcon && con->flags & CON_BOOT) {
  2751				/*
  2752				 * Make sure to unregister boot consoles whose data
  2753				 * resides in the init section before the init section
  2754				 * is discarded. Boot consoles whose data will stick
  2755				 * around will automatically be unregistered when the
  2756				 * proper console replaces them.
  2757				 */
  2758				if (init_section_intersects(con, sizeof(*con)))
  2759					unregister_console(con);
  2760			}
  2761		}
  2762		ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL,
  2763						console_cpu_notify);
  2764		WARN_ON(ret < 0);
  2765		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "printk:online",
  2766						console_cpu_notify, NULL);
  2767		WARN_ON(ret < 0);
  2768		return 0;
  2769	}
  2770	late_initcall(printk_late_init);
  2771	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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