[lkml]   [2018]   [Mar]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: arm crypto .S_shipped files sometimes get rebuilt randomly
2018-03-08 4:25 GMT+09:00 Leonard Crestez <>:
> Hello,
> I am using a toolchain with a broken/old version of perl which doesn't
> include 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)/
> $(call cmd,perlasm)
> If a decision to rerun the rule is made based on their relative
> timestamps but both .S_shipped and 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)/
$(call cmd,perlasm)

$(obj)/sha512-core.S: $(src)/
$(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

$(src)/sha256-core.S_shipped: $(src)/
$(call cmd,perlasm)

$(src)/sha512-core.S_shipped: $(src)/
$(call cmd,perlasm)

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

 \ /
  Last update: 2018-03-08 07:18    [W:0.077 / U:0.692 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site