[PATCH v2 00/13] arm64: suspend/resume implementation

Lorenzo Pieralisi lorenzo.pieralisi at arm.com
Mon Oct 14 07:02:57 EDT 2013

This series is v2 of a previous posting:


Patchset depends on M.Rutland arm64 CPU hotplug series:


CPU idle driver and PSCI suspend implementation used for testing are not
published as part of this series since they depend on standardization
of PSCI bindings for C-states; code can be made available on a separate branch
if required.

v2 changes:

- Rebased to 3.12-rc4
- Changed cpu_suspend prototype
- Added macros to save/restore CPU registers
- Improved register/load/store scheduling in context save/restore
- Changed Kconfig option
- Refactored the stack allocation and context struct layout
- Fixed a bug in cpu_suspend return path
- Added tick broadcast support
- Dropped RFC tag

This patch series provides an implementation of suspend/resume and
related CPU PM notifiers for the arm64 architecture. The implementation
has been tweaked and code made a bit more generic wrt ARM 32 bits
version. The cpu_suspend call prototype accepts a single parameter that
is translated by the CPU operations suspend protocol backend into a
series of protocol (eg PSCI) specific parameters and function calls.
This allows for generic suspend-to-RAM and CPU idle drivers, where the
platform complexity is hidden behind the CPU ops suspend protocol

The context restore split between processor specific functions and
generic code has been kept similar to arm32 as well, since this makes
sense from a functionality perspective, even though there is just a
an architecture specific save/restore implementation for arm64, for v8.
Code that deals with turning on the MMU and returning from suspend is kept
in the same file as the the suspend method itself, so that assembly code is
self contained in a single file and separated from the interface.

The CPU register context is allocated on the stack; this behaviour is
the same as in the arm 32-bit port, even though context could have been
allocated statically as a NR_CPUS array of struct and the context
addresses stored once of all in the context pointers array after virtual
to physical conversion. Current solution uses the stack, since there is
no need to allocate additional context space for context that can be
easily saved on the suspend threads stacks, with no additional memory

Cache flushing is kept to a minimum; the cpu_suspend method cleans only the
few bytes of context to DRAM that need to be retrieved with the MMU off,
the remainder of cache cleaning is delegated to suspend finishers.

The series also provides patches to simplify the MPIDR_EL1 management
and MPIDR_EL1 hashing that are integrated to the series but are also useful
as stand alone code.

Code has been tested on AEM v8 models and a simple CPU idle driver that
enables a C-state where CPUs are shutdown when wfi is hit.

KVM CPU PM notifier has been tested using kvm-tools, and by booting a KVM guest
on a host with deep idle states enabled.

HW breakpoint CPU PM notifier has been tested using a simple perf test that
sets up per-cpu watchpoints and checks the proper behaviour when deep idle
states are enabled.

Lorenzo Pieralisi (13):
  arm64: kernel: add MPIDR_EL1 accessors macros
  arm64: kernel: build MPIDR_EL1 hash function data structure
  arm64: kernel: suspend/resume registers save/restore
  arm64: kernel: cpu_{suspend/resume} implementation
  arm64: add CPU PM infrastructure selection
  arm64: kernel: implement fpsimd CPU PM notifier
  arm: kvm: implement CPU PM notifier
  arm64: kernel: implement debug monitors CPU PM notifiers
  arm64: kernel: refactor code to install/uninstall breakpoints
  arm64: kernel: implement HW breakpoints CPU PM notifier
  arm64: enable generic clockevent broadcast
  arm64: kernel: add CPU idle call
  arm64: add CPU power management menu/entries

 arch/arm/kvm/arm.c                     |  30 +++++
 arch/arm64/Kconfig                     |  21 ++++
 arch/arm64/include/asm/cpu_ops.h       |   6 +
 arch/arm64/include/asm/cputype.h       |  10 ++
 arch/arm64/include/asm/hardirq.h       |   2 +-
 arch/arm64/include/asm/proc-fns.h      |   3 +
 arch/arm64/include/asm/smp_plat.h      |  13 +++
 arch/arm64/include/asm/suspend.h       |  36 ++++++
 arch/arm64/include/asm/suspendmacros.h |  75 ++++++++++++
 arch/arm64/kernel/Makefile             |   1 +
 arch/arm64/kernel/asm-offsets.c        |  11 ++
 arch/arm64/kernel/debug-monitors.c     |  38 ++++++
 arch/arm64/kernel/fpsimd.c             |  36 ++++++
 arch/arm64/kernel/hw_breakpoint.c      | 205 ++++++++++++++++++++++++---------
 arch/arm64/kernel/process.c            |   7 +-
 arch/arm64/kernel/setup.c              |  70 +++++++++++
 arch/arm64/kernel/sleep.S              | 191 ++++++++++++++++++++++++++++++
 arch/arm64/kernel/smp.c                |  17 +++
 arch/arm64/kernel/suspend.c            |  93 +++++++++++++++
 arch/arm64/mm/proc.S                   |  30 +++++
 20 files changed, 836 insertions(+), 59 deletions(-)
 create mode 100644 arch/arm64/include/asm/suspend.h
 create mode 100644 arch/arm64/include/asm/suspendmacros.h
 create mode 100644 arch/arm64/kernel/sleep.S
 create mode 100644 arch/arm64/kernel/suspend.c


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