This patch series is intended for use alongside the Implement MODVERSIONS for RUST [1] series as a replacement for the symbol name hashing approach used there 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. If you are testing this patch alongside RUST by manually removing the !MODVERSIONS restriction (this series doesn't remove it, because the CRCs don't mean what we'd want them to yet, we need the DWARF patch for that) and have kernel hardening enabled, you may need the CPU Mitigations [5] series. Without it, the foo.mod.o file produced by the C compiler will reference __x86_return_thunk, but foo.o will not. This means that the version table will not contain a version for __x86_return_thunk, but foo.ko will reference it, which will result in a version check failure. This series depends upon the module verification refactor patches [6] that were split off of v5. [1] https://lore.kernel.org/all/20240617175818.58219-17-samitolvanen@xxxxxxxxxx/ [2] https://lore.kernel.org/lkml/20240605032120.3179157-1-song@xxxxxxxxxx/ [3] https://lore.kernel.org/lkml/ZoxbEEsK40ASi1cY@xxxxxxxxxxxxxxxxxxxxxx/ [4] https://lore.kernel.org/lkml/0b2697fd-7ab4-469f-83a6-ec9ebc701ba0@xxxxxxxx/ [5] https://lore.kernel.org/all/20240725183325.122827-1-ojeda@xxxxxxxxxx/ [6] https://lore.kernel.org/linux-modules/20241015231651.3851138-1-mmaurer@xxxxxxxxxx/T/#t Changes in v6: - 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@xxxxxxxxxx/ - 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@xxxxxxxxxx/ - 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@xxxxxxxxxx/ - Add loading/verification refactor before modifying, per Luis's request v1: https://lore.kernel.org/rust-for-linux/20231115185858.2110875-1-mmaurer@xxxxxxxxxx/ 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
