mbox series

[v7,0/3] Extended MODVERSIONS Support

Message ID 20241023-extended-modversions-v7-0-339787b43373@google.com (mailing list archive)
Headers show
Series Extended MODVERSIONS Support | expand

Message

Matthew Maurer Oct. 23, 2024, 2:31 a.m. UTC 
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].

linuxppc-dev is requested to look at the ppc-specific munging,
as Luis would like some eyes on there [6].

[1] https://lore.kernel.org/lkml/20241008183823.36676-21-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
[6] https://lore.kernel.org/lkml/ZxahDv5ZKdM__0sZ@bombadil.infradead.org/

Changes in v7:
- 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/

Matthew Maurer (5):
  export_report: Rehabilitate script
  modules: Support extended MODVERSIONS info
  export_report: Tolerate additional `.mod.c` content
  modpost: Produce extended MODVERSIONS information
  export_report: Use new version info format

 arch/powerpc/kernel/module_64.c | 23 ++++++++-
 kernel/module/Kconfig           |  8 +++
 kernel/module/internal.h        | 11 ++++
 kernel/module/main.c            | 92 ++++++++++++++++++++++++++++++---
 kernel/module/version.c         | 45 ++++++++++++++++
 scripts/export_report.pl        | 17 +++---
 scripts/mod/modpost.c           | 41 +++++++++++++++
 7 files changed, 220 insertions(+), 17 deletions(-)

--
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                   | 32 +++++++++++++-
 scripts/Makefile.modpost        |  1 +
 scripts/mod/modpost.c           | 65 +++++++++++++++++++++++++++--
 9 files changed, 266 insertions(+), 17 deletions(-)
---
base-commit: 2295cf87ed5a6da4564034e4f8ebcce0a0a021ed
change-id: 20241022-extended-modversions-a7b44dfbfff1
prerequisite-message-id: <20241008183823.36676-21-samitolvanen@google.com>
prerequisite-patch-id: 08b46e0d1e37c262c08da6db4a87728d7b3047cc
prerequisite-patch-id: 97f307e05ec4b7a653f1ec68f825e8d5bd622b05
prerequisite-patch-id: a4519fb5eef33d692b918529ae094845f822b718
prerequisite-patch-id: e192e2a692c40d96cba919e3baae68c441ab25e4
prerequisite-patch-id: 58359b851618c2b6582e02e11ac54d7cd0375853
prerequisite-patch-id: 4d6a826429c519b581d01215e1d9c7373fdfd8c6
prerequisite-patch-id: 0dcd84187b222adf52696dbcab303d683d087dd2
prerequisite-patch-id: 0abe8634eb844a85e8dc51c1cd3970cf96cc494a
prerequisite-patch-id: c9b1a36f177f5bd25cc5a9236f4839e972c12333
prerequisite-patch-id: b7b61991d74f0a0a0b8f50f7eeb3c306261ee512
prerequisite-patch-id: f6c97ecaaa62cee387d7bb83e3dd6d5fda44cafd
prerequisite-patch-id: 6182973041c913f727b289228e7e3e19de09c999
prerequisite-patch-id: d688fb99eb5d6152fece6068c1b3a434c5750109
prerequisite-patch-id: f09e5d7c8bbba276b0e3a244a89b6bb18f692fa1
prerequisite-patch-id: 66ffe1d8df889b254a0f29992d9c0356676ed489
prerequisite-patch-id: a372f88626c3dda51eab6c6af132a76141ff20cc
prerequisite-patch-id: 57d2fe708769154a6494fb1fece56911dea00687
prerequisite-patch-id: 18ddc778b1a3b263db34e906eb74e9d15602ce68
prerequisite-patch-id: 8297655807a95e5a5522edaa0c082888c8a0286f

Best regards,

Comments

Sami Tolvanen Oct. 24, 2024, 11:07 p.m. UTC | #1 
On Wed, Oct 23, 2024 at 02:31:27AM +0000, Matthew Maurer wrote:
> 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].
> 
> linuxppc-dev is requested to look at the ppc-specific munging,
> as Luis would like some eyes on there [6].
> 
> [1] https://lore.kernel.org/lkml/20241008183823.36676-21-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
> [6] https://lore.kernel.org/lkml/ZxahDv5ZKdM__0sZ@bombadil.infradead.org/
> 
> Changes in v7:
> - Fix modpost to detect EXTENDED_MODVERSIONS based on a flag
> - Drop patches to fix export_report.pl

Unless Luis prefers to deal with this separately, perhaps you can
just include a patch to delete export_report.pl in this series?

Sami
Luis Chamberlain Oct. 25, 2024, 4:53 a.m. UTC | #2 
On Thu, Oct 24, 2024 at 11:07:57PM +0000, Sami Tolvanen wrote:
> > Changes in v7:
> > - Fix modpost to detect EXTENDED_MODVERSIONS based on a flag
> > - Drop patches to fix export_report.pl
> 
> Unless Luis prefers to deal with this separately, perhaps you can
> just include a patch to delete export_report.pl in this series?

Yes, please do the homework to check the history of export_report.pl
and just nuke it if we don't need it. Ignoring it just because it may
not be used is not the right thing.

If you don't find the history on the current tree we have the
history.git tree [0] I often use to go down memory lane pre-git.

[0] https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/

  Luis