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. Emitting the existing format is now guarded by CONFIG_BASIC_MODVERSIONS, but it is enabled by default when MODVERSIONS is enabled and must be explicitly disabled by the user. Disabling CONFIG_BASIC_MODVERSIONS may cause some userspace tools to be unable to retrieve CRCs until they are patched to understand the new location. Even with CONFIG_BASIC_MODVERSIONS enabled, those tools will be unable to read the CRCs for long symbols until they are updated to read the new format. This is not expected to interfere with normal operation, as the primary use for CRCs embedded in the module is load-time verification by the kernel. Recording and monitoring of CRCs is typically done through Module.symvers. Selecting RUST and MODVERSIONS is now possible if GENDWARFKSYMS is selected, and will implicitly select EXTENDED_MODVERSIONS. This series depends upon DWARF-based versions [1]. [1] https://lore.kernel.org/lkml/20241219210736.2990838-20-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/ Changes in v11: - Fixed documentation about where strings are stored per Petr's suggestion. - Rebased on to the latest version of Sami's series on linux-next v10: https://lore.kernel.org/r/20241123-extended-modversions-v10-0-0fa754ffdee3@xxxxxxxxxx - Fixed accidental selects / default confusion in previous patch - Re-ran tests (check for section presence in Y/Y, Y/N, N/Y, N/N, check all module kinds load) v9: https://lore.kernel.org/r/20241123-extended-modversions-v9-0-bc0403f054bf@xxxxxxxxxx - Rebased onto the latest version of Sami's series, on top of linux-next - Added BASIC_MODVERSIONS to allow using *only* EXTENDED_MODVERSIONS - Documented where symbol data is stored and format limitations v8: https://lore.kernel.org/r/20241030-extended-modversions-v8-0-93acdef62ce8@xxxxxxxxxx - 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@xxxxxxxxxx - 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@xxxxxxxxxx/ - 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/ -- 2.47.0.rc1.288.g06298d1525-goog --- Matthew Maurer (4): modules: Support extended MODVERSIONS info modpost: Produce extended MODVERSIONS information modules: Allow extended modversions without basic MODVERSIONS Documentation/kbuild: Document storage of symbol information Sami Tolvanen (1): rust: Use gendwarfksyms + extended modversions for CONFIG_MODVERSIONS Documentation/kbuild/modules.rst | 20 +++++++++ arch/powerpc/kernel/module_64.c | 24 ++++++++++- init/Kconfig | 3 +- kernel/module/Kconfig | 25 +++++++++++ kernel/module/internal.h | 11 +++++ kernel/module/main.c | 92 ++++++++++++++++++++++++++++++++++++---- kernel/module/version.c | 45 ++++++++++++++++++++ rust/Makefile | 34 ++++++++++++++- scripts/Makefile.modpost | 2 + scripts/mod/modpost.c | 70 +++++++++++++++++++++++++++--- 10 files changed, 308 insertions(+), 18 deletions(-) --- base-commit: b2c5bc987160cbc8478b982991f34f53189af909 change-id: 20241022-extended-modversions-a7b44dfbfff1 prerequisite-message-id: <20241219210736.2990838-20-samitolvanen@xxxxxxxxxx> prerequisite-patch-id: 8a6a82b2f1858ee1483f41a1aa72c8cb030559ac prerequisite-patch-id: 5b22bc2e7f592e464d5d1dd4341efa2fb2afb9d0 prerequisite-patch-id: 220585cf1a8d66ec722cf1d6ec474af6dc3b6a02 prerequisite-patch-id: 8ae7cb66d809f902968f81354706edeb99a3d3fa prerequisite-patch-id: 4d6a826429c519b581d01215e1d9c7373fdfd8c6 prerequisite-patch-id: 0dcd84187b222adf52696dbcab303d683d087dd2 prerequisite-patch-id: 0abe8634eb844a85e8dc51c1cd3970cf96cc494a prerequisite-patch-id: 5fabb630792f9304f200b5996314f3c2ae4c83ae prerequisite-patch-id: 2772364d4b2132c9ede451f320162fc40c6f3d09 prerequisite-patch-id: a5cf20d27871bf63be64ac79cc81e5eb9d117b89 prerequisite-patch-id: 930230702709fe769b171a8ae94955e5d1de13ea prerequisite-patch-id: b43c0bc886a312e3b14be04a8fdad25badf4d834 prerequisite-patch-id: 839b0c4859bdc8447d67bfe4b09f762140e747e7 prerequisite-patch-id: 3c55d1e58a1d7aebfc3ea85ef5497a7262022040 prerequisite-patch-id: 5a190c60e140cdf33caf4f4da03186a2bd75a531 prerequisite-patch-id: 57d2fe708769154a6494fb1fece56911dea00687 prerequisite-patch-id: 7e046331b05c61a87e1adc923b763b68a580cd03 prerequisite-patch-id: 91c6131ab67a6f0fd8cf8bc95fa45144a868f095 Best regards, -- Matthew Maurer <mmaurer@xxxxxxxxxx>
