linux-kernel - Re: [PATCH v4 00/21] Unify <linux/export.h> and <asm/export.h>, remove EXPORT_DATA_SYMBOL(), faster TRIM_UNUSED

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Message-ID: <CAK7LNASDzy9RERN6+q6WgR4ROYZQue=SBqgbcoYuVePByHtk6Q@mail.gmail.com>
Date:   Sun, 14 May 2023 21:43:31 +0900
From:   Masahiro Yamada <masahiroy@...nel.org>
To:     linux-kbuild@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Nicolas Pitre <npitre@...libre.com>,
        Nicolas Schier <nicolas@...sle.eu>
Subject: Re: [PATCH v4 00/21] Unify <linux/export.h> and <asm/export.h>,
 remove EXPORT_DATA_SYMBOL(), faster TRIM_UNUSED_KSYMS

On Sun, May 14, 2023 at 5:45 AM Masahiro Yamada <masahiroy@...nel.org> wrote:
>
>
> This patch set refactors modpost first to make it easier to
> add new code.
>
> Main goals:
>
>  - Refactors EXPORT_SYMBOL, <linux/export.h> and <asm/export.h>.
>    You can still put EXPORT_SYMBOL() in *.S file, very close to the definition,
>    but you do not need to care about whether it is a function or a data.
>    This removes EXPORT_DATA_SYMBOL().
>
>  - Re-implement TRIM_UNUSED_KSYMS in one-pass.
>    This makes the building faster.
>
>  - Move the static EXPORT_SYMBOL check to modpost.
>    This also makes the building faster.
>
> Previous version
> v3: https://lore.kernel.org/all/20220928063947.299333-1-masahiroy@kernel.org/
>



After more testing, I noticed some issues.





- modpost: simplify find_elf_symbol()
  has a regression.
  I will get a wrong name for 'static' symbols.
  I will fix it or drop it.

- modpost: pass struct module pointer to check_section_mismatch()
  causes a build error, (but fixed by the next commit)

- kbuild: generate KSYMTAB entries by modpost
  This causes build errors on ARM.
  I will fix it.


I will send v5.



>
> Masahiro Yamada (21):
>   modpost: remove broken calculation of exception_table_entry size
>   modpost: remove fromsym info in __ex_table section mismatch warning
>   modpost: remove get_prettyname()
>   modpost: squash report_extable_warnings() into
>     extable_mismatch_handler()
>   modpost: squash report_sec_mismatch() into default_mismatch_handler()
>   modpost: clean up is_executable_section()
>   modpost: squash extable_mismatch_handler() into
>     default_mismatch_handler()
>   modpost: pass 'tosec' down to default_mismatch_handler()
>   modpost: pass section index to find_elf_symbol2()
>   modpost: simplify find_elf_symbol()
>   modpost: rename find_elf_symbol() and find_elf_symbol2()
>   modpost: unify 'sym' and 'to' in default_mismatch_handler()
>   modpost: replace r->r_offset, r->r_addend with faddr, taddr
>   modpost: remove is_shndx_special() check from section_rel(a)
>   modpost: pass struct module pointer to check_section_mismatch()
>   kbuild: generate KSYMTAB entries by modpost
>   ia64,export.h: replace EXPORT_DATA_SYMBOL* with EXPORT_SYMBOL*
>   modpost: check static EXPORT_SYMBOL* by modpost again
>   modpost: squash sym_update_namespace() into sym_add_exported()
>   modpost: use null string instead of NULL pointer for default namespace
>   kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion
>
>  .gitignore                        |   1 -
>  Makefile                          |  19 +-
>  arch/ia64/include/asm/Kbuild      |   1 +
>  arch/ia64/include/asm/export.h    |   3 -
>  arch/ia64/kernel/head.S           |   2 +-
>  arch/ia64/kernel/ivt.S            |   2 +-
>  include/asm-generic/export.h      |  83 +----
>  include/asm-generic/vmlinux.lds.h |   1 +
>  include/linux/export-internal.h   |  49 +++
>  include/linux/export.h            | 116 ++-----
>  include/linux/pm.h                |   8 +-
>  kernel/module/internal.h          |  12 +
>  scripts/Makefile.build            |  19 +-
>  scripts/Makefile.modpost          |   7 +
>  scripts/adjust_autoksyms.sh       |  73 ----
>  scripts/basic/fixdep.c            |   3 +-
>  scripts/check-local-export        |  70 ----
>  scripts/gen_ksymdeps.sh           |  30 --
>  scripts/mod/modpost.c             | 534 ++++++++++++------------------
>  scripts/mod/modpost.h             |   1 +
>  scripts/remove-stale-files        |   2 +
>  21 files changed, 317 insertions(+), 719 deletions(-)
>  delete mode 100644 arch/ia64/include/asm/export.h
>  delete mode 100755 scripts/adjust_autoksyms.sh
>  delete mode 100755 scripts/check-local-export
>  delete mode 100755 scripts/gen_ksymdeps.sh
>
> --
> 2.39.2
>


-- 
Best Regards
Masahiro Yamada