Messages in this thread | | | From | Masahiro Yamada <> | Date | Thu, 8 Mar 2018 14:00:03 +0900 | Subject | Re: arm crypto .S_shipped files sometimes get rebuilt randomly |
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2018-03-08 4:25 GMT+09:00 Leonard Crestez <leonard.crestez@nxp.com>: > Hello, > > I am using a toolchain with a broken/old version of perl which doesn't > include integer.pm and I noticed it triggers occasional build failures > on arch/arm64/crypto/sha512-core.S_shipped. Workarounds are easy, but > if the purpose of the .S_shipped is to avoid the need to have all > dependencies on the build machine then something went wrong? > > This was introduced by commit 7918ecef073f ("crypto: arm64/sha2 - > integrate OpenSSL implementations of SHA256/SHA512"). The makefile > rules are not terribly complicated: > > quiet_cmd_perlasm = PERLASM $@ > cmd_perlasm = $(PERL) $(<) void $(@) > > $(src)/sha512-core.S_shipped: $(src)/sha512-armv8.pl > $(call cmd,perlasm) > > If a decision to rerun the rule is made based on their relative > timestamps but both .S_shipped and sha512-armv8.pl are included in git > then won't the result be essentially random, depending on file checkout > order? > > I see random success/failure by just running something like the > following multiple times: > rm -rf arch/arm64/crypto > git co -f arch/arm64/crypto > make -- arch/arm64/crypto/ > > A reasonable fix might be to simply drop .S_shipped and require a > functional recent version of perl. Then if it fails it will fail > reliably. >
Indeed, this Makefile is weird. We have two choices.
[1] If we intend to generate sha{256,512}-core.S from the perl script during the build, this should be:
$(obj)/sha512-core.S: $(src)/sha512-armv8.pl $(call cmd,perlasm)
$(obj)/sha512-core.S: $(src)/sha512-armv8.pl $(call cmd,perlasm)
[2] If we want to check-in _shipped files and avoid running perl during the build, we can surround unnecessary rules with if-conditional, like
if REGENERATE_ARM64_SHA $(src)/sha256-core.S_shipped: $(src)/sha512-armv8.pl $(call cmd,perlasm)
$(src)/sha512-core.S_shipped: $(src)/sha512-armv8.pl $(call cmd,perlasm) endif
Set REGENERATE_ARM64_SHA=1 from the command line only when you need to update the _shipped files.
This is what commit 7373f4f83c71d50f0aece6d94309ab7fde42180f did.
Recently, Kconfig switched to [1]. So, flex and bison are required to build the kernel.
-- Best Regards Masahiro Yamada
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