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| author | Masahiro Yamada <masahiroy@kernel.org> | 2022-05-27 19:01:53 +0900 |
|---|---|---|
| committer | Masahiro Yamada <masahiroy@kernel.org> | 2022-06-01 23:07:29 +0900 |
| commit | c6031b1dbbbfec03891bf1baefa2e0803d705601 (patch) | |
| tree | 173a64a7a43628e63041a824f6879811838b3460 /scripts/Makefile.build | |
| parent | cd968b97c49214e6557381bddddacbd0e0fb696e (diff) | |
| download | lwn-c6031b1dbbbfec03891bf1baefa2e0803d705601.tar.gz lwn-c6031b1dbbbfec03891bf1baefa2e0803d705601.zip | |
kbuild: make *.mod rule robust against too long argument error
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>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
Diffstat (limited to 'scripts/Makefile.build')
| -rw-r--r-- | scripts/Makefile.build | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 3c1e20e4a4fc..a1edbfe4310b 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -275,8 +275,10 @@ $(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[$$0]++' > $@ +# To make this rule robust against "Argument list too long" error, +# ensure to add $(obj)/ prefix by a shell command. +cmd_mod = echo $(call real-search, $*.o, .o, -objs -y -m) | \ + $(AWK) -v RS='( |\n)' '!x[$$0]++ { print("$(obj)/"$$0) }' > $@ $(obj)/%.mod: FORCE $(call if_changed,mod) |