kernel/git/stable/linux.git/scripts/mod/modpost.c, branch linux-6.13.y

kbuild: keep symbols for symbol_get() even with CONFIG_TRIM_UNUSED_KSYMS

2025-03-22T19:56:45+00:00

[ Upstream commit 4c56eb33e603c3b9eb4bd24efbfdd0283c1c37e4 ] Linus observed that the symbol_request(utf8_data_table) call fails when CONFIG_UNICODE=y and CONFIG_TRIM_UNUSED_KSYMS=y. symbol_get() relies on the symbol data being present in the ksymtab for symbol lookups. However, EXPORT_SYMBOL_GPL(utf8_data_table) is dropped due to CONFIG_TRIM_UNUSED_KSYMS, as no module references it in this case. Probably, this has been broken since commit dbacb0ef670d ("kconfig option for TRIM_UNUSED_KSYMS"). This commit addresses the issue by leveraging modpost. Symbol names passed to symbol_get() are recorded in the special .no_trim_symbol section, which is then parsed by modpost to forcibly keep such symbols. The .no_trim_symbol section is discarded by the linker scripts, so there is no impact on the size of the final vmlinux or modules. This commit cannot resolve the issue for direct calls to __symbol_get() because the symbol name is not known at compile-time. Although symbol_get() may eventually be deprecated, this workaround should be good enough meanwhile. Reported-by: Linus Torvalds Suggested-by: Linus Torvalds Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

modpost: work around unaligned data access error

2024-12-28T14:31:09+00:00

With the latest binutils, modpost fails with a bus error on some architectures such as ARM and sparc64. Since binutils commit 1f1b5e506bf0 ("bfd/ELF: restrict file alignment for object files"), the byte offset to each section (sh_offset) in relocatable ELF is no longer guaranteed to be aligned. modpost parses MODULE_DEVICE_TABLE() data structures, which are usually located in the .rodata section. If it is not properly aligned, unaligned access errors may occur. To address the issue, this commit imports the get_unaligned() helper from include/linux/unaligned.h. The get_unaligned_native() helper caters to the endianness in addition to handling the unaligned access. I slightly refactored do_pcmcia_entry() and do_input() to avoid writing back to an unaligned address. (We would need the put_unaligned() helper to do that.) The addend_*_rel() functions need similar adjustments because the .text sections are not aligned either. It seems that the .symtab, .rel.* and .rela.* sections are still aligned. Keep normal pointer access for these sections to avoid unnecessary performance costs. Reported-by: Paulo Pisati Reported-by: Matthias Klose Closes: https://sourceware.org/bugzilla/show_bug.cgi?id=32435 Reported-by: John Paul Adrian Glaubitz Closes: https://sourceware.org/bugzilla/show_bug.cgi?id=32493 Signed-off-by: Masahiro Yamada Tested-by: John Paul Adrian Glaubitz

modpost: distinguish same module paths from different dump files

2024-12-21T03:42:10+00:00

Since commit 13b25489b6f8 ("kbuild: change working directory to external module directory with M="), module paths are always relative to the top of the external module tree. The module paths recorded in Module.symvers are no longer globally unique when they are passed via KBUILD_EXTRA_SYMBOLS for building other external modules, which may result in false-positive "exported twice" errors. Such errors should not occur because external modules should be able to override in-tree modules. To address this, record the dump file path in struct module and check it when searching for a module. Fixes: 13b25489b6f8 ("kbuild: change working directory to external module directory with M=") Reported-by: Jon Hunter Closes: https://lore.kernel.org/all/eb21a546-a19c-40df-b821-bbba80f19a3d@nvidia.com/ Signed-off-by: Masahiro Yamada Tested-by: Jon Hunter

modpost: Add .irqentry.text to OTHER_SECTIONS

2024-12-08T08:11:34+00:00

The compiler can fully inline the actual handler function of an interrupt entry into the .irqentry.text entry point. If such a function contains an access which has an exception table entry, modpost complains about a section mismatch: WARNING: vmlinux.o(__ex_table+0x447c): Section mismatch in reference ... The relocation at __ex_table+0x447c references section ".irqentry.text" which is not in the list of authorized sections. Add .irqentry.text to OTHER_SECTIONS to cure the issue. Reported-by: Sergey Senozhatsky Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org # needed for linux-5.4-y Link: https://lore.kernel.org/all/20241128111844.GE10431@google.com/ Signed-off-by: Masahiro Yamada

modpost: replace tdb_hash() with hash_str()

2024-11-27T23:46:03+00:00

Use a helper available in scripts/include/hash.h. Signed-off-by: Masahiro Yamada

modpost: move strstarts() to modpost.h

2024-11-27T23:46:02+00:00

This macro is useful in file2alias.c as well. Signed-off-by: Masahiro Yamada

modpost: introduce module_alias_printf() helper

2024-11-27T23:42:58+00:00

The generic ->do_entry() handler is currently limited to returning a single alias string. However, this is not flexible enough for several subsystems, which currently require their own implementations: - do_usb_table() - do_of_table() - do_pnp_device_entry() - do_pnp_card_entries() This commit introduces a helper function so that these special cases can add multiple MODULE_ALIAS() and then migrate to the generic framework. Signed-off-by: Masahiro Yamada

kbuild: compile constant module information only once

2024-09-07T08:24:08+00:00

Various information about modules is compiled into the info sections. For that a dedicated .mod.c file is generated by modpost for each module and then linked into the module. However most of the information in the .mod.c is the same for all modules, internal and external. Split the shared information into a dedicated source file that is compiled once and then linked into all modules. This avoids frequent rebuilds for all .mod.c files when using CONFIG_LOCALVERSION_AUTO because the local version ends up in .mod.c through UTS_RELEASE and VERMAGIC_STRING. The modules are still relinked in this case. The code is also easier to maintain as it's now in a proper source file instead of an inline string literal. Signed-off-by: Thomas Weißschuh Signed-off-by: Masahiro Yamada

modpost: simplify modpost_log()

2024-09-01T11:34:50+00:00

With commit cda5f94e88b4 ("modpost: avoid using the alias attribute"), only two log levels remain: LOG_WARN and LOG_ERROR. Simplify this by making it a boolean variable. Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor

modpost: improve the section mismatch warning format

2024-09-01T11:34:49+00:00

This commit improves the section mismatch warning format when there is no suitable symbol name to print. The section mismatch warning prints the reference source in the form of + and the reference destination in the form of . However, there are some corner cases where becomes "(unknown)", as reported in commit 23dfd914d2bf ("modpost: fix null pointer dereference"). In such cases, it is better to print the symbol address. Signed-off-by: Masahiro Yamada