[PATCH AUTOSEL 5.7 322/388] modpost: fix -i (--ignore-errors) MAKEFLAGS detection

Sasha Levin
2020-06-18T01:17:49Z

From: Masahiro Yamada <masahiroy@kernel.org>

[ Upstream commit 91e6ee581270b8ae970f028b898314d73f16870b ]

$(filter -i,$(MAKEFLAGS)) works only in limited use-cases.

The representation of $(MAKEFLAGS) depends on various factors:
- GNU Make version (version 3.8x or version 4.x)
- The presence of other flags like -j

In my experiments, $(MAKEFLAGS) is expanded as follows:

* GNU Make 3.8x:

* without -j option:
--no-print-directory -Rri

* with -j option:
--no-print-directory -Rr --jobserver-fds=3,4 -j -i

* GNU Make 4.x:

* without -j option:
irR --no-print-directory

* with -j option:
irR -j --jobserver-fds=3,4 --no-print-directory

For GNU Make 4.x, the flags are grouped as 'irR', which does not work.

For the single thread build with GNU Make 3.8x, the flags are grouped
as '-Rri', which does not work either.

To make it work for all cases, do likewise as commit 6f0fa58e4596
("kbuild: simplify silent build (-s) detection").

BTW, since commit ff9b45c55b26 ("kbuild: modpost: read modules.order
instead of $(MODVERDIR)/*.mod"), you also need to pass -k option to
build final *.ko files. 'make -i -k' ignores compile errors in modules,
and build as many remaining *.ko as possible.

Please note this feature is kind of dangerous if other modules depend
on the broken module because the generated modules will lack the correct
module dependency or CRC. Honestly, I am not a big fan of it, but I am
keeping this feature.

Fixes: eed380f3f593 ("modpost: Optionally ignore secondary errors seen if a single module build fails")
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
scripts/Makefile.modpost | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost
index 957eed6a17a5..33aaa572f686 100644
--- a/scripts/Makefile.modpost
+++ b/scripts/Makefile.modpost
@@ -66,7 +66,7 @@ __modpost:

else

-MODPOST += $(subst -i,-n,$(filter -i,$(MAKEFLAGS))) -s -T - \
+MODPOST += -s -T - \
$(if $(KBUILD_NSDEPS),-d $(MODULES_NSDEPS))

ifeq ($(KBUILD_EXTMOD),)
@@ -82,6 +82,11 @@ include $(if $(wildcard $(KBUILD_EXTMOD)/Kbuild), \
$(KBUILD_EXTMOD)/Kbuild, $(KBUILD_EXTMOD)/Makefile)
endif

+# 'make -i -k' ignores compile errors, and builds as many modules as possible.
+ifneq ($(findstring i,$(filter-out --%,$(MAKEFLAGS))),)
+MODPOST += -n
+endif
+
# find all modules listed in modules.order
modules := $(sort $(shell cat $(MODORDER)))

--
2.25.1