[v4,0/2] Drivers: hv: Move Hyper-V clock/timer code to separate clocksource driver

Message

Michael Kelley (LINUX) June 28, 2019, 6:33 p.m. UTC

This patch series moves Hyper-V clock/timer code to a separate Hyper-V
clocksource driver. Previously, Hyper-V clock/timer code and data
structures were mixed in with other Hyper-V code in the ISA independent
drivers/hv code as well as in ISA dependent code. The new Hyper-V
clocksource driver is ISA independent, with a just few dependencies on
ISA specific functions. The patch series does not change any behavior
or functionality -- it only reorganizes the existing code and fixes up
the linkages. A few places outside of Hyper-V code are fixed up to use
the new #include file structure.

This restructuring is in response to Marc Zyngier's review comments
on supporting Hyper-V running on ARM64, and is a good idea in general.
It increases the amount of code shared between the x86 and ARM64
architectures, and reduces the size of the new code for supporting
Hyper-V on ARM64. A new version of the Hyper-V on ARM64 patches will
follow once this clocksource restructuring is accepted.

The code is diff'ed against the upstream tip tree:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers/vdso

Changes in v4:
* Revised commit messages
* Rebased to upstream tip tree

Changes in v3:
* Removed boolean argument to hv_init_clocksource(). Always call
sched_clock_register, which is needed on ARM64 but a no-op on x86.
* Removed separate cpuhp setup in hv_stimer_alloc() and instead
directly call hv_stimer_init() and hv_stimer_cleanup() from
corresponding VMbus functions.  This more closely matches original
code and avoids clocksource stop/restart problems on ARM64 when
VMbus code denies CPU offlining request.

Changes in v2:
* Revised commit short descriptions so the distinction between
the first and second patches is clearer [GregKH]
* Renamed new clocksource driver files and functions to use
existing "timer" and "stimer" names instead of introducing
"syntimer". [Vitaly Kuznetsov]
* Introduced CONFIG_HYPER_TIMER to fix build problem when
CONFIG_HYPERV=m [Vitaly Kuznetsov]
* Added "Suggested-by: Marc Zyngier"

Michael Kelley (2):
  Drivers: hv: Create Hyper-V clocksource driver from existing
    clockevents code
  Drivers: hv: Move Hyper-V clocksource code to new clocksource driver

 MAINTAINERS                              |   2 +
 arch/x86/entry/vdso/vma.c                |   2 +-
 arch/x86/hyperv/hv_init.c                |  91 +--------
 arch/x86/include/asm/hyperv-tlfs.h       |   6 +
 arch/x86/include/asm/mshyperv.h          |  81 ++------
 arch/x86/include/asm/vdso/gettimeofday.h |   2 +-
 arch/x86/kernel/cpu/mshyperv.c           |   2 +
 arch/x86/kvm/x86.c                       |   1 +
 drivers/clocksource/Makefile             |   1 +
 drivers/clocksource/hyperv_timer.c       | 321 +++++++++++++++++++++++++++++++
 drivers/hv/Kconfig                       |   3 +
 drivers/hv/hv.c                          | 156 +--------------
 drivers/hv/hyperv_vmbus.h                |   3 -
 drivers/hv/vmbus_drv.c                   |  42 ++--
 include/clocksource/hyperv_timer.h       | 105 ++++++++++
 15 files changed, 483 insertions(+), 335 deletions(-)
 create mode 100644 drivers/clocksource/hyperv_timer.c
 create mode 100644 include/clocksource/hyperv_timer.h