[PATCH 0/2] make POSIX timers configurable

[Nicolas Pitre]

Many embedded systems don't need the full POSIX timer support.
Configuring them out provides a nice kernel image size reduction.

When POSIX timers are configured out, the PTP clock subsystem should be
left out as well. However a bunch of ethernet drivers currently *select*
it in their Kconfig entries. Therefore some more tweaks were needed to
break that hard dependency for those drivers to still be configured in
if desired.

It was agreed that the best path upstream for those patches is via
John Stultz's timer tree.

Previous itterations of those patches and the discussion threads can be
found here:

  https://lkml.org/lkml/2016/9/14/992

  https://lkml.org/lkml/2016/9/14/803

  https://lkml.org/lkml/2016/9/8/793

diffstat:

 drivers/Makefile                                |   2 +-
 drivers/net/ethernet/adi/Kconfig                |   8 +-
 drivers/net/ethernet/amd/Kconfig                |   2 +-
 drivers/net/ethernet/amd/xgbe/xgbe-main.c       |   6 +-
 drivers/net/ethernet/broadcom/Kconfig           |   4 +-
 drivers/net/ethernet/cavium/Kconfig             |   2 +-
 drivers/net/ethernet/freescale/Kconfig          |   2 +-
 drivers/net/ethernet/intel/Kconfig              |  10 +-
 drivers/net/ethernet/intel/e1000e/ptp.c         |   2 +-
 drivers/net/ethernet/intel/i40e/i40e_ptp.c      |   2 +-
 drivers/net/ethernet/intel/igb/igb_ptp.c        |   2 +-
 drivers/net/ethernet/intel/ixgbe/ixgbe_ptp.c    |   2 +-
 drivers/net/ethernet/mellanox/mlx4/Kconfig      |   2 +-
 drivers/net/ethernet/mellanox/mlx4/en_clock.c   |   2 +-
 drivers/net/ethernet/mellanox/mlx5/core/Kconfig |   2 +-
 .../net/ethernet/mellanox/mlx5/core/en_clock.c  |   2 +-
 drivers/net/ethernet/renesas/Kconfig            |   2 +-
 drivers/net/ethernet/samsung/Kconfig            |   2 +-
 drivers/net/ethernet/sfc/Kconfig                |   2 +-
 drivers/net/ethernet/sfc/ptp.c                  |  14 +--
 drivers/net/ethernet/stmicro/stmmac/Kconfig     |   2 +-
 .../net/ethernet/stmicro/stmmac/stmmac_ptp.c    |   2 +-
 drivers/net/ethernet/ti/Kconfig                 |   2 +-
 drivers/net/ethernet/tile/Kconfig               |   2 +-
 drivers/ptp/Kconfig                             |  14 ++-
 include/linux/posix-timers.h                    |  28 ++++-
 include/linux/ptp_clock_kernel.h                |  59 ++++++---
 include/linux/sched.h                           |  10 ++
 init/Kconfig                                    |  17 +++
 kernel/signal.c                                 |   4 +
 kernel/time/Kconfig                             |   1 +
 kernel/time/Makefile                            |  10 +-
 kernel/time/posix-stubs.c                       | 118 ++++++++++++++++++
 33 files changed, 277 insertions(+), 64 deletions(-)