[PATCH v2 0/5] MODVERSIONS + RUST Redux

Matthew Maurer
2023-11-18T02:58:07Z

The goal of this patch series is to allow MODVERSIONS and RUST to be
enabled simultaneously. The primary issue with doing this at the moment
is that Rust uses some extremely long symbol names - for those
unfamiliar with Rust, it may be helpful to think of some of the mangled
C++ names you may have seen in binaries in the past.

Previously, Gary Guo attempted to accomplish this by modifying the
existing modversion format [1] to support variable-length symbol names.
This was unfortunately considered to be a potential userspace break
because kmod tools inspect this kernel module metadata. Masahiro Yamada
suggested [2] that this could instead be done with a section per-field.
This gives us the ability to be more flexible with this format in the
future, as a new field or additional information will be in a new
section which userspace tools will not yet attempt to read.

In the previous version of this patchset, Luis Chamberlain suggested [3]
I move validation out of the version checking and into the elf validity
checker, and also add kernel-docs over there. I found
elf_validity_cached_copy to be fairly dense and difficult to directly
describe, so I refactored it into easier to explain pieces. In the
process, I found a few missing checks and added those as well. See
[PATCH 2/5] for more details. If this is too much, I'm more than happy
to drop this patch from the series in favor of just adding the
kernel-doc to the original code, but figured I'd offer it up in case the
added clarity and checks were valuable.

[1] https://lore.kernel.org/lkml/20230111161155.1349375-1-gary@garyguo.net/
[2] https://lore.kernel.org/lkml/CAK7LNATsuszFR7JB5ZkqVS1W=hWr9=E7bTf+MvgJ+NXT3aZNwg@mail.gmail.com/
[3] https://lore.kernel.org/lkml/ZVZNh%2FPA5HiVRkeb@bombadil.infradead.org/

Matthew Maurer (5):
export_report: Rehabilitate script
modules: Refactor + kdoc elf_validity_cached_copy
modpost: Extended modversion support
rust: Allow MODVERSIONS
export_report: Use new version info format

arch/powerpc/kernel/module_64.c | 25 +-
init/Kconfig | 1 -
kernel/module/internal.h | 18 +-
kernel/module/main.c | 663 +++++++++++++++++++++++++-------
kernel/module/version.c | 43 +++
scripts/export_report.pl | 17 +-
scripts/mod/modpost.c | 37 +-
7 files changed, 642 insertions(+), 162 deletions(-)

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2.43.0.rc0.421.g78406f8d94-goog