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Deepa Dinamani 152194fe9c Input: extend usable life of event timestamps to 2106 on 32 bit systems
The input events use struct timeval to store event time, unfortunately
this structure is not y2038 safe and is being replaced in kernel with
y2038 safe structures.

Because of ABI concerns we can not change the size or the layout of
structure input_event, so we opt to re-interpreting the 'seconds' part
of timestamp as an unsigned value, effectively doubling the range of
values, to year 2106.

Newer glibc that has support for 32 bit applications to use 64 bit
time_t supplies __USE_TIME_BITS64 define [1], that we can use to present
the userspace with updated input_event layout. The updated layout will
cause the compile time breakage, alerting applications and distributions
maintainers to the issue. Existing 32 binaries will continue working
without any changes until 2038.

Ultimately userspace applications should switch to using monotonic or
boot time clocks, as realtime clock is not very well suited for input
event timestamps as it can go backwards (see a80b83b7b8 "Input: evdev -
add CLOCK_BOOTTIME support" by by John Stultz). With monotonic clock the
practical range of reported times will always fit into the pair of 32
bit values, as we do not expect any system to stay up for a hundred
years without a single reboot.

[1] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Acked-by: Peter Hutterer <peter.hutterer@who-t.net>
Patchwork-Id: 10148083
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2018-01-09 16:40:30 -08:00
Documentation Input: silead - add support for capactive home button found on some x86 tablets 2018-01-09 16:38:06 -08:00
arch Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-05 12:14:50 -08:00
block License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
certs License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
crypto License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
drivers Input: extend usable life of event timestamps to 2106 on 32 bit systems 2018-01-09 16:40:30 -08:00
firmware License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fs fs/hugetlbfs/inode.c: fix hwpoison reserve accounting 2017-11-03 07:39:19 -07:00
include Input: extend usable life of event timestamps to 2106 on 32 bit systems 2018-01-09 16:40:30 -08:00
init License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
ipc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kernel Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-05 11:44:39 -08:00
lib License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
mm mm, swap: fix race between swap count continuation operations 2017-11-03 07:39:19 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-03 09:09:21 -07:00
samples License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
scripts Kbuild: don't pass "-C" to preprocessor when processing linker scripts 2017-11-02 14:10:37 -07:00
security License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
sound License cleanup: add SPDX license identifiers to some files 2017-11-02 10:04:46 -07:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-11-05 11:44:39 -08:00
usr initramfs: fix initramfs rebuilds w/ compression after disabling 2017-11-03 07:39:19 -07:00
virt Fixes for interrupt controller emulation in ARM/ARM64 and x86, plus a one-liner 2017-11-04 11:44:55 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap Update MIPS email addresses 2017-11-03 09:02:30 -07:00
COPYING
CREDITS selinux/stable-4.14 PR 20170831 2017-09-12 13:21:00 -07:00
Kbuild License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS MIPS fixes for 4.14 2017-11-04 11:31:02 -07:00
Makefile Linux 4.14-rc8 2017-11-05 13:05:14 -08:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.