Message-ID: <20241030-extended-modversions-v8-0-93acdef62ce8@google.com>
Date: Wed, 30 Oct 2024 23:05:01 +0000
From: Matthew Maurer <mmaurer@...gle.com>
To: Michael Ellerman <mpe@...erman.id.au>, Nicholas Piggin <npiggin@...il.com>, 
	Christophe Leroy <christophe.leroy@...roup.eu>, Naveen N Rao <naveen@...nel.org>, 
	Madhavan Srinivasan <maddy@...ux.ibm.com>, Luis Chamberlain <mcgrof@...nel.org>, 
	Petr Pavlu <petr.pavlu@...e.com>, Sami Tolvanen <samitolvanen@...gle.com>, 
	Daniel Gomez <da.gomez@...sung.com>, Masahiro Yamada <masahiroy@...nel.org>, 
	Nathan Chancellor <nathan@...nel.org>, Nicolas Schier <nicolas@...sle.eu>, Miguel Ojeda <ojeda@...nel.org>, 
	Alex Gaynor <alex.gaynor@...il.com>, Boqun Feng <boqun.feng@...il.com>, 
	Gary Guo <gary@...yguo.net>, 
	"Björn Roy Baron" <bjorn3_gh@...tonmail.com>, Benno Lossin <benno.lossin@...ton.me>, 
	Andreas Hindborg <a.hindborg@...nel.org>, Alice Ryhl <aliceryhl@...gle.com>, 
	Trevor Gross <tmgross@...ch.edu>
Cc: linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org, 
	linux-modules@...r.kernel.org, linux-kbuild@...r.kernel.org, 
	rust-for-linux@...r.kernel.org, Matthew Maurer <mmaurer@...gle.com>
Subject: [PATCH v8 0/3] Extended MODVERSIONS Support

This patch series is intended for use alongside the Implement DWARF
modversions series [1] to enable RUST and MODVERSIONS at the same
time.

Elsewhere, we've seen a desire for long symbol name support for LTO
symbol names [2], and the previous series came up [3] as a possible
solution rather than hashing, which some have objected [4] to.

This series adds a MODVERSIONS format which uses a section per column.
This avoids userspace tools breaking if we need to make a similar change
to the format in the future - we would do so by adding a new section,
rather than editing the struct definition. In the new format, the name
section is formatted as a concatenated sequence of NUL-terminated
strings, which allows for arbitrary length names.

Emitting the extended format is guarded by CONFIG_EXTENDED_MODVERSIONS,
but the kernel always knows how to validate both the original and
extended formats.

Selecting RUST and MODVERSIONS is now possible if GENDWARFKSYMS is
selected, and will implicitly select EXTENDED_MODVERSIONS.

This series depends upon the module verification refactor patches [5]
that were split off of v5, and DWARF-based versions [1].

[1] https://lore.kernel.org/lkml/20241030170106.1501763-21-samitolvanen@google.com/
[2] https://lore.kernel.org/lkml/20240605032120.3179157-1-song@kernel.org/
[3] https://lore.kernel.org/lkml/ZoxbEEsK40ASi1cY@bombadil.infradead.org/
[4] https://lore.kernel.org/lkml/0b2697fd-7ab4-469f-83a6-ec9ebc701ba0@suse.com/
[5] https://lore.kernel.org/linux-modules/20241015231651.3851138-1-mmaurer@google.com/T/#t

Changes in v8:
- Rebased onto latest version of Sami's series, on top of v6.12-rc5
- Pass --stable when KBUILD_GENDWARFKSYMS_STABLE is set.
- Flipped MODVERSIONS/GENDWARFKSYMS order in deps for CONFIG_RUST
- Picked up trailers

v7: https://lore.kernel.org/r/20241023-extended-modversions-v7-0-339787b43373@google.com
- Fix modpost to detect EXTENDED_MODVERSIONS based on a flag
- Drop patches to fix export_report.pl
- Switch from conditional compilation in .mod.c to conditional emission
  in modpost
- Factored extended modversion emission into its own function
- Allow RUST + MODVERSIONS if GENDWARFKSYMS is enabled by selecting
  EXTENDED_MODVERSIONS

v6: https://lore.kernel.org/lkml/20241015231925.3854230-1-mmaurer@google.com/
- Splits verification refactor Luis requested out to a separate change
- Clarifies commits around export_report.pl repairs
- Add CONFIG_EXTENDED_MODVERSIONS to control whether extended
  information is included in the module, per Luis's request.

v5: https://lore.kernel.org/all/20240925233854.90072-1-mmaurer@google.com/
- Addresses Sami's comments from v3 that I missed in v4 (missing early
  return, extra parens)

v4: https://lore.kernel.org/asahi/20240924212024.540574-1-mmaurer@google.com/
- Fix incorrect dot munging in PPC

v3: https://lore.kernel.org/lkml/87le0w2hop.fsf@mail.lhotse/T/
- Split up the module verification refactor into smaller patches, per
  Greg K-H's suggestion.

v2: https://lore.kernel.org/all/20231118025748.2778044-1-mmaurer@google.com/
- Add loading/verification refactor before modifying, per Luis's request

v1: https://lore.kernel.org/rust-for-linux/20231115185858.2110875-1-mmaurer@google.com/

--
2.47.0.rc1.288.g06298d1525-goog

---
Matthew Maurer (2):
      modules: Support extended MODVERSIONS info
      modpost: Produce extended MODVERSIONS information

Sami Tolvanen (1):
      rust: Use gendwarfksyms + extended modversions for CONFIG_MODVERSIONS

 arch/powerpc/kernel/module_64.c | 24 ++++++++++-
 init/Kconfig                    |  3 +-
 kernel/module/Kconfig           | 10 +++++
 kernel/module/internal.h        | 11 +++++
 kernel/module/main.c            | 92 +++++++++++++++++++++++++++++++++++++----
 kernel/module/version.c         | 45 ++++++++++++++++++++
 rust/Makefile                   | 33 ++++++++++++++-
 scripts/Makefile.modpost        |  1 +
 scripts/mod/modpost.c           | 65 +++++++++++++++++++++++++++--
 9 files changed, 267 insertions(+), 17 deletions(-)
---
base-commit: ac746e6156c4d6d7b46ba2102acf644ea2aa4aac
change-id: 20241022-extended-modversions-a7b44dfbfff1
prerequisite-message-id: <20241015231651.3851138-1-mmaurer@...gle.com>
prerequisite-patch-id: 7b7bf0c0c0f484703e29a452dc99dc99711c051b
prerequisite-patch-id: 8cc51bc35ddd4c268b5ccba4c3a74af3dbee8bee
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prerequisite-patch-id: e2f5364a0c5f3c9341aaa183f97fb7544b1c9dba
prerequisite-message-id: <20241030170106.1501763-21-samitolvanen@...gle.com>
prerequisite-patch-id: 08b46e0d1e37c262c08da6db4a87728d7b3047cc
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prerequisite-patch-id: c21f85ffe5c7684c1ffc87af716e2e50498d5c92
prerequisite-patch-id: a372f88626c3dda51eab6c6af132a76141ff20cc
prerequisite-patch-id: 57d2fe708769154a6494fb1fece56911dea00687
prerequisite-patch-id: e5fb35555f6a95bc9953bddebba0612f422146c4
prerequisite-patch-id: 624e6794e5003cff734873894c2343595b45244b

Best regards,
-- 
Matthew Maurer <mmaurer@...gle.com>

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