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authorMasahiro Yamada <masahiroy@kernel.org>2021-05-17 16:03:13 +0900
committerMasahiro Yamada <masahiroy@kernel.org>2021-05-27 04:01:50 +0900
commit174a1dcc96429efce4ef7eb2f5c4506480da2182 (patch)
tree445f80762b34cc19ceef753539c38315252e3872 /scripts/Kbuild.include
parent41eba23efba38b2bc4c33e3c00441e196ebdac55 (diff)
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kbuild: sink stdout from cmd for silent build
When building with 'make -s', no output to stdout should be printed. As Arnd Bergmann reported [1], mkimage shows the detailed information of the generated images. I think this should be suppressed by the 'cmd' macro instead of by individual scripts. Insert 'exec >/dev/null;' in order to redirect stdout to /dev/null for silent builds. [Note about this implementation] 'exec >/dev/null;' may look somewhat tricky, but this has a reason. Appending '>/dev/null' at the end of command line is a common way for redirection, so I first tried this: cmd = @set -e; $(echo-cmd) $(cmd_$(1)) >/dev/null ... but it would not work if $(cmd_$(1)) itself contains a redirection. For example, cmd_wrap in scripts/Makefile.asm-generic redirects the output from the 'echo' command into the target file. It would be expanded into: echo "#include <asm-generic/$*.h>" > $@ >/dev/null Then, the target file gets empty because the string will go to /dev/null instead of $@. Next, I tried this: cmd = @set -e; $(echo-cmd) { $(cmd_$(1)); } >/dev/null The form above would be expanded into: { echo "#include <asm-generic/$*.h>" > $@; } >/dev/null This works as expected. However, it would be a syntax error if $(cmd_$(1)) is empty. When CONFIG_TRIM_UNUSED_KSYMS is disabled, $(call cmd,gen_ksymdeps) in scripts/Makefile.build would be expanded into: set -e; { ; } >/dev/null ..., which causes an syntax error. I also tried this: cmd = @set -e; $(echo-cmd) ( $(cmd_$(1)) ) >/dev/null ... but this causes a syntax error for the same reason. So, finally I adopted: cmd = @set -e; $(echo-cmd) exec >/dev/null; $(cmd_$(1)) [1]: https://lore.kernel.org/lkml/20210514135752.2910387-1-arnd@kernel.org/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'scripts/Kbuild.include')
-rw-r--r--scripts/Kbuild.include7
1 files changed, 6 insertions, 1 deletions
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 82dd1b65b7a8..f247e691562d 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -90,8 +90,13 @@ clean := -f $(srctree)/scripts/Makefile.clean obj
echo-cmd = $(if $($(quiet)cmd_$(1)),\
echo ' $(call escsq,$($(quiet)cmd_$(1)))$(echo-why)';)
+# sink stdout for 'make -s'
+ redirect :=
+ quiet_redirect :=
+silent_redirect := exec >/dev/null;
+
# printing commands
-cmd = @set -e; $(echo-cmd) $(cmd_$(1))
+cmd = @set -e; $(echo-cmd) $($(quiet)redirect) $(cmd_$(1))
###
# if_changed - execute command if any prerequisite is newer than