From: Nicolas Schier <nicolas@fjasle.eu>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: linux-kbuild@vger.kernel.org, clang-built-linux@googlegroups.com,
linux-kernel@vger.kernel.org, Ard Biesheuvel <ardb@kernel.org>,
Luis Chamberlain <mcgrof@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
linuxppc-dev@lists.ozlabs.org, linux-um@lists.infradead.org,
linux-s390@vger.kernel.org,
Nick Desaulniers <ndesaulniers@google.com>,
Sami Tolvanen <samitolvanen@google.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v3 15/15] kbuild: make *.mod rule robust against too long argument error
Date: Thu, 5 May 2022 22:31:28 +0200 [thread overview]
Message-ID: <YnQ0IHNnQTIsxOxq@fjasle.eu> (raw)
In-Reply-To: <20220505072244.1155033-16-masahiroy@kernel.org>
On Thu, May 05, 2022 at 04:22:44PM +0900 Masahiro Yamada wrote:
> Like built-in.a, the command length of the *.mod rule scales with
> the depth of the directory times the number of objects in the Makefile.
>
> Add $(obj)/ by the shell command (awk) instead of by Make's builtin
> function.
>
> In-tree modules still have some room to the limit (ARG_MAX=2097152),
> but this is more future-proof for big modules in a deep directory.
>
> For example, you can build i915 as a module (CONFIG_DRM_I915=m) and
> compare drivers/gpu/drm/i915/.i915.mod.cmd with/without this commit.
>
> The issue is more critical for external modules because the M= path
> can be very long as Jeff Johnson reported before [1].
>
> [1] https://lore.kernel.org/linux-kbuild/4c02050c4e95e4cb8cc04282695f8404@codeaurora.org/
>
> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
> ---
>
> (no changes since v2)
>
> Changes in v2:
> - New patch
>
> scripts/Makefile.build | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index cea48762299c..e7b3f329d443 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -266,8 +266,8 @@ $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
> $(call if_changed_rule,cc_o_c)
> $(call cmd,force_checksrc)
>
> -cmd_mod = echo $(addprefix $(obj)/, $(call real-search, $*.o, .o, -objs -y -m)) | \
> - $(AWK) -v RS='( |\n)' '!x[$$0]++' > $@
> +cmd_mod = echo $(call real-search, $*.o, .o, -objs -y -m) | \
> + $(AWK) -v RS='( |\n)' '!x[$$0]++ { print("$(obj)/"$$0) }' > $@
>
> $(obj)/%.mod: FORCE
> $(call if_changed,mod)
> --
> 2.32.0
Thanks! At work, some colleagues of mine stumbled over that problem, too.
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
next prev parent reply other threads:[~2022-05-05 20:38 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-05 7:22 [PATCH v3 00/15] kbuild: yet another series of cleanups (modpost, LTO, MODULE_REL_CRCS) Masahiro Yamada
2022-05-05 7:22 ` [PATCH v3 01/15] modpost: mitigate false-negatives for static EXPORT_SYMBOL checks Masahiro Yamada
2022-05-05 19:25 ` Nicolas Schier
2022-05-05 7:22 ` [PATCH v3 02/15] modpost: change the license of EXPORT_SYMBOL to bool type Masahiro Yamada
2022-05-05 13:48 ` Masahiro Yamada
2022-05-05 19:53 ` Nicolas Schier
2022-05-05 7:22 ` [PATCH v3 03/15] modpost: merge add_{intree_flag,retpoline,staging_flag} to add_header Masahiro Yamada
2022-05-05 19:58 ` Nicolas Schier
2022-05-05 7:22 ` [PATCH v3 04/15] modpost: move *.mod.c generation to write_mod_c_files() Masahiro Yamada
2022-05-05 20:06 ` Nicolas Schier
2022-05-05 7:22 ` [PATCH v3 05/15] kbuild: generate a list of objects in vmlinux Masahiro Yamada
2022-05-05 7:22 ` [PATCH v3 06/15] kbuild: record symbol versions in *.cmd files Masahiro Yamada
2022-05-05 7:22 ` [PATCH v3 07/15] modpost: extract symbol versions from " Masahiro Yamada
2022-05-05 20:09 ` Nicolas Schier
2022-05-05 7:22 ` [PATCH v3 08/15] kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS Masahiro Yamada
2022-05-05 7:22 ` [PATCH v3 09/15] kbuild: stop merging *.symversions Masahiro Yamada
2022-05-05 20:19 ` Nicolas Schier
2022-05-05 7:22 ` [PATCH v3 10/15] genksyms: adjust the output format to modpost Masahiro Yamada
2022-05-05 20:22 ` Nicolas Schier
2022-05-05 7:22 ` [PATCH v3 11/15] kbuild: do not create *.prelink.o for Clang LTO or IBT Masahiro Yamada
2022-05-05 7:22 ` [PATCH v3 12/15] modpost: simplify the ->is_static initialization Masahiro Yamada
2022-05-05 20:27 ` Nicolas Schier
2022-05-05 7:22 ` [PATCH v3 13/15] modpost: use hlist for hash table implementation Masahiro Yamada
2022-05-05 7:22 ` [PATCH v3 14/15] kbuild: make built-in.a rule robust against too long argument error Masahiro Yamada
2022-05-05 20:29 ` Nicolas Schier
2022-05-05 20:31 ` Nick Desaulniers
2022-05-05 7:22 ` [PATCH v3 15/15] kbuild: make *.mod " Masahiro Yamada
2022-05-05 20:31 ` Nicolas Schier [this message]
2022-05-05 16:49 ` [PATCH v3 00/15] kbuild: yet another series of cleanups (modpost, LTO, MODULE_REL_CRCS) Masahiro Yamada
2022-05-06 22:45 ` Nathan Chancellor
2022-05-08 18:28 ` Masahiro Yamada
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