This two patch series, tries to introduce an architecture independent
method to calculate the 'info->page_offset' value for x86_64
and arm64 architectures, by reading the VMCOREINFO note in
'/proc/kcore'.
Since linux kernel commit 23c85094fe1895caefdd
["proc/kcore: add vmcoreinfo note to /proc/kcore"]), '/proc/kcore'
contains a new PT_NOTE which carries the VMCOREINFO information.
If the same is available, one can use it in user-land to
retrieve machine specific symbols or strings being appended to the
vmcoreinfo even for live-debugging of the primary kernel as a
standard interface exposed by kernel for sharing machine specific
details with the user-land.
I understand that there might be some reservations about exporting
such machine-specific details in the vmcoreinfo, but to unify
the implementations across user-land and archs, perhaps this would be
good starting point to start a discussion.
Here are brief details of the patches in this patchset:
- PATCH 1/2: Calculates 'info->page_offset' for arm64 arch via
vmcoreinfo note inside '/proc/kcore'.
- PATCH 2/2: Calculates 'info->page_offset' for x86_64 arch via
vmcoreinfo note inside '/proc/kcore', thus fixing a makedumpfile
'--mem-usage' breakage with latest kernels on x86_64.
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Kazuhito Hagio <k-hagio@xxxxxxxxxxxxx>
Bhupesh Sharma (2):
makedumpfile/arm64: Use VMCOREINFO inside '/proc/kcore' (if available)
makedumpfile/x86_64: Add 'page_offset_base' reading capability from
VMCOREINFO
arch/arm64.c | 114 +++++++++++++++++++++++++++++++++++++++++++--------------
arch/x86_64.c | 17 +++++++++
makedumpfile.c | 69 +++++++++++++++++++++++++++++++---
makedumpfile.h | 3 +-
4 files changed, 169 insertions(+), 34 deletions(-)
--
2.7.4
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