[Crash-utility] [PATCH v4 0/6] Generalize KASLR calculation and use it for KDUMPs

[Sergio Lopez]

Commit 45b74b89530d611b3fa95a1041e158fbb865fa84 added support for
calculating phys_base and kernel offset for KASLR-enabled kernels on
SADUMPs by using a technique developed by Takao Indoh. Originally, the
patchset included support for KDUMPs, but this was dropped in v2, as it
was deemed unnecessary due to the implementation of the vmcoreinfo
device in QEMU.

Sadly, there are many reasons for which the vmcoreinfo device may not be
present in the moment of taking the memory dump from a VM, ranging from
a Host running older QEMU/libvirt versions, to misconfigured VMs or
environments running Hypervisors that doesn't support this device.

This patchset generalizes the kaslr related functions from sadump.c
moving them to kaslr_helper.c, and makes KDUMP analysis fallback to
KASLR offset calculation if vmcoreinfo data is missing.

These changes have been successfully tested with a 3.10.0-830.el7.x86_64
under the following conditions:

 - kdump with KASLR and vmcoreinfo

 - kdump with KASLR but no vmcoreinfo

 - kdump without KASLR ("nokaslr" kernel command line option)

It was also tested that a "crash" patched with these changes still
builds and runs (live and kdump debugging) on an aarch64 machine.

changelog:

v4:
 - Add missing brackets in map_cpus_to_prstatus_kdump_cmprs (thanks
   Dave)
 - Apply coding style suggestions.
 - Add support for VMWARE VMSS dumps (vmware_vmss)
 - Update copyright and authors on kaslr_helper.c and vmware_vmss.c

v3:
 - Merge *get_cr3 and *get_idtr functions and move them to
   kaslr_helper.c
 - diskdump: drop kaslr_phys_base addition and use
   sub_header_kdump->phys_base instead.
 - Unconditionally call x86_64_virt_phys_base after grabbing phys_base

v2:
 - Limit application to QEMU ELF and QEMU COMPRESSED dumps (thanks Dave)
 - Add support for QEMU COMPRESSED dumps (diskdump)

Sergio Lopez (6):
  Move kaslr related functions from sadump.c to kaslr_helper.c
  Move QEMUCPU* structs from netdump.h to defs.h
  netdump: infer kaslr offset for QEMU ELF dumps without vmcoreinfo
  diskdump: infer kaslr offset for QEMU COMPRESSED dumps without
    vmcoreinfo
  vmware_vmss: infer kaslr offset for VMSS dumps
  kaslr_helper/vmware_vmss: update copyright and authors

 Makefile       |   7 +-
 defs.h         |  43 +++++
 diskdump.c     |  66 +++++++-
 kaslr_helper.c | 494 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 netdump.c      |  57 +++++++
 netdump.h      |  24 +--
 sadump.c       | 486 ++++----------------------------------------------------
 symbols.c      |  30 +++-
 vmware_vmss.c  |  32 +++-
 vmware_vmss.h  |   1 +
 x86_64.c       |  34 +++-
 11 files changed, 788 insertions(+), 486 deletions(-)
 create mode 100644 kaslr_helper.c

-- 
2.14.3