Add basic kexec support to Mini-OS for running in x86 PVH mode.

With this series applied it is possible to activate another kernel
from within Mini-OS.

Right now no Xen related teardown is done (so no reset of grant table,
event channels, PV devices). These should be added via kexec callbacks
which are added as a framework.

This is a major building block for support of Xenstore-stubdom live
update (in fact I've tested the kexec path to work using the PVH
variant of Xenstore-stubdom).

Changes in V2:
- addressed comments

Juergen Gross (12):
  add kexec framework
  Mini-OS: add final kexec stage
  mini-os: add elf.h
  mini-os: analyze new kernel for kexec
  mini-os: kexec: finalize parameter location and size
  mini-os: reserve memory below boundary
  mini-os: kexec: build parameters for new kernel
  mini-os: kexec: move used pages away for new kernel
  Mini-OS: mm: change set_readonly() to change_readonly()
  Mini-OS: kexec: switch read-only area to be writable again
  mini-os: kexec: add kexec callback functionality
  mini-os: kexec: do the final kexec step

 Config.mk                  |   1 +
 Makefile                   |   1 +
 arch/x86/kexec.c           | 272 +++++++++++++++++++++++++++++++++
 arch/x86/minios-x86.lds.S  |  17 +++
 arch/x86/mm.c              | 238 ++++++++++++++++++++++-------
 arch/x86/testbuild/all-no  |   1 +
 arch/x86/testbuild/all-yes |   2 +
 arch/x86/testbuild/kexec   |   4 +
 arch/x86/x86_hvm.S         |  46 ++++++
 include/elf.h              | 300 +++++++++++++++++++++++++++++++++++++
 include/kexec.h            |  63 ++++++++
 include/mm.h               |   8 +
 include/x86/os.h           |   5 +
 kexec.c                    | 252 +++++++++++++++++++++++++++++++
 mm.c                       |  89 ++++++++++-
 15 files changed, 1248 insertions(+), 51 deletions(-)
 create mode 100644 arch/x86/kexec.c
 create mode 100644 arch/x86/testbuild/kexec
 create mode 100644 include/elf.h
 create mode 100644 include/kexec.h
 create mode 100644 kexec.c

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2.43.0