[PATCH v4 0/4] makedumpfile/arm64: Add support for ARMv8.2 extensions

[Bhupesh Sharma <bhsharma@redhat.com>]

Changes since v3:
----------------
- v3 can be seen here:
  http://lists.infradead.org/pipermail/kexec/2019-March/022534.html
- Added a new patch (via [PATCH 4/4]) which marks '--mem-usage' option as
  unsupported for arm64 architecture. With the newer arm64 kernels
  supporting 48-bit/52-bit VA address spaces and keeping a single
  binary for supporting the same, the address of
  kernel symbols like _stext, which could be earlier used to determine
  VA_BITS value, can no longer to determine whether VA_BITS is set to 48
  or 52 in the kernel space. Hence for now, it makes sense to mark
  '--mem-usage' option as unsupported for arm64 architecture until
  we have more clarity from arm64 kernel maintainers on how to manage
  the same in future kernel/makedumpfile versions.

Changes since v2:
----------------
- v2 can be seen here:
  http://lists.infradead.org/pipermail/kexec/2019-February/022456.html
- I missed some comments from Kazu sent on the LVA v1 patch when I sent
  out the v2. So, addressing them now in v3.
- Also added a patch that adds a tree-wide feature to read
  'MAX_PHYSMEM_BITS' from vmcoreinfo (if available).

Changes since v1:
----------------
- v1 was sent as two separate patches:
  http://lists.infradead.org/pipermail/kexec/2019-February/022424.html
  (ARMv8.2-LPA)
  http://lists.infradead.org/pipermail/kexec/2019-February/022425.html
  (ARMv8.2-LVA)
- v2 combined the two in a single patchset and also addresses Kazu's
  review comments.

This patchset adds support for ARMv8.2 extensions in makedumpfile code.
I cover the following two cases with this patchset:
 - 48-bit kernel VA + 52-bit PA (LPA)
 - 52-bit kernel VA (LVA) + 52-bit PA (LPA)
 - 48-bit kernel VA + 52-bit user-space VA (LVA)
 - 52-bit kernel VA + 52-bit user-space VA (Full LVA)

This has been tested for the following user-cases:
1. Creating a dumpfile using /proc/vmcore,
2. Creating a dumpfile using /proc/kcore, and
3. Post-processing a vmcore.

I have tested this patchset on the following platforms, with kernels
which support/do-not-support ARMv8.2 features:
1. CPUs which don't support ARMv8.2 features, e.g. qualcomm-amberwing,
   ampere-osprey.
2. Prototype models which support ARMv8.2 extensions (e.g. ARMv8 FVP
   simulation model).

Also a preparation patch has been added in this patchset which adds a
common feature for archs (except arm64, for which similar support is
added via subsequent patch) to retrieve 'MAX_PHYSMEM_BITS' from
vmcoreinfo (if available).

I recently posted two kernel patches (see [0] and [1]) which append
'TCR_EL1.T1SZ' and 'MAX_PHYSMEM_BITS' to vmcoreinfo in the kernel
code, so that user-space code can benefit from the same.

This patchset ensures backward compatibility for kernel versions in
which 'TCR_EL1.T1SZ' and 'MAX_PHYSMEM_BITS' are not available in
vmcoreinfo.

[0]. http://lists.infradead.org/pipermail/kexec/2019-November/023960.html
[1]. http://lists.infradead.org/pipermail/kexec/2019-November/023962.html

Cc: John Donnelly <john.p.donnelly@oracle.com>
Cc: Kazuhito Hagio <k-hagio@ab.jp.nec.com>
Cc: kexec@lists.infradead.org

Bhupesh Sharma (4):
  tree-wide: Retrieve 'MAX_PHYSMEM_BITS' from vmcoreinfo (if available)
  makedumpfile/arm64: Add support for ARMv8.2-LPA (52-bit PA support)
  makedumpfile/arm64: Add support for ARMv8.2-LVA (52-bit kernel VA
    support)
  makedumpfile: Mark --mem-usage option unsupported for arm64

 arch/arm.c     |   8 +-
 arch/arm64.c   | 438 ++++++++++++++++++++++++++++++++++++++++++---------------
 arch/ia64.c    |   7 +-
 arch/ppc.c     |   8 +-
 arch/ppc64.c   |  49 ++++---
 arch/s390x.c   |  29 ++--
 arch/sparc64.c |   9 +-
 arch/x86.c     |  34 +++--
 arch/x86_64.c  |  27 ++--
 makedumpfile.c |   7 +
 makedumpfile.h |   3 +-
 11 files changed, 439 insertions(+), 180 deletions(-)

-- 
2.7.4


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