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Masahiro Yamada 4c56eb33e6 kbuild: keep symbols for symbol_get() even with CONFIG_TRIM_UNUSED_KSYMS 
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 dbacb0ef67 ("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 <torvalds@linux-foundation.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2025-02-06 01:08:58 +09:00
..
.gitignore
devicetable-offsets.c usb: typec: Only use SVID for matching altmodes 2024-12-24 08:56:05 +01:00
empty.c
file2alias.c Merge 6.13-rc7 into usb-next 2025-01-13 06:11:06 +01:00
Makefile Makefile: remove redundant tool coverage variables 2024-05-14 23:35:48 +09:00
mk_elfconfig.c modpost: detect endianness on run-time 2024-09-01 20:33:32 +09:00
modpost.c kbuild: keep symbols for symbol_get() even with CONFIG_TRIM_UNUSED_KSYMS 2025-02-06 01:08:58 +09:00
modpost.h kbuild: keep symbols for symbol_get() even with CONFIG_TRIM_UNUSED_KSYMS 2025-02-06 01:08:58 +09:00
sumversion.c sumversion: Fix a memory leak in get_src_version() 2024-10-23 16:11:13 +09:00
symsearch.c modpost: replace the use of NOFAIL() with xmalloc() etc. 2024-09-01 20:34:48 +09:00