kernel/linux.git/scripts/mod/modpost.h, branch v6.18.21

modpost: Create modalias for builtin modules

2025-09-24T16:10:45+00:00

For some modules, modalias is generated using the modpost utility and the section is added to the module file. When a module is added inside vmlinux, modpost does not generate modalias for such modules and the information is lost. As a result kmod (which uses modules.builtin.modinfo in userspace) cannot determine that modalias is handled by a builtin kernel module. $ cat /sys/devices/pci0000:00/0000:00:14.0/modalias pci:v00008086d0000A36Dsv00001043sd00008694bc0Csc03i30 $ modinfo xhci_pci name: xhci_pci filename: (builtin) license: GPL file: drivers/usb/host/xhci-pci description: xHCI PCI Host Controller Driver Missing modalias "pci:v*d*sv*sd*bc0Csc03i30*" which will be generated by modpost if the module is built separately. To fix this it is necessary to generate the same modalias for vmlinux as for the individual modules. Fortunately '.vmlinux.export.o' is already generated from which '.modinfo' can be extracted in the same way as for vmlinux.o. Signed-off-by: Masahiro Yamada Signed-off-by: Alexey Gladkov Tested-by: Stephen Rothwell Reviewed-by: Nicolas Schier Link: https://patch.msgid.link/28d4da3b0e3fc8474142746bcf469e03752c3208.1758182101.git.legion@kernel.org Signed-off-by: Nathan Chancellor

modpost: introduce get_basename() helper

2025-03-15T12:16:21+00:00

The logic to retrieve the basename appears multiple times. Factor out the common pattern into a helper function. I copied kbasename() from include/linux/string.h and renamed it to get_basename(). Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier

kbuild: keep symbols for symbol_get() even with CONFIG_TRIM_UNUSED_KSYMS

2025-02-05T16:08:58+00:00

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

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: 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

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: replace the use of NOFAIL() with xmalloc() etc.

2024-09-01T11:34:48+00:00

I think x*alloc() functions are cleaner. Signed-off-by: Masahiro Yamada

modpost: detect endianness on run-time

2024-09-01T11:33:32+00:00

Endianness is currently detected on compile-time, but we can defer this until run-time. This change avoids re-executing scripts/mod/mk_elfconfig even if modpost in the linux-headers package needs to be rebuilt for a foreign architecture. Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier