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    SubjectRe: [GIT PULL] Crypto Fixes for 5.6
    On Thu, Mar 12, 2020 at 4:57 AM Herbert Xu <herbert@gondor.apana.org.au> wrote:
    >
    > This push fixes a build problem with x86/curve25519.

    Pulled.

    I do have a comment, though: this fix matches the existing pattern of
    checking for assembler support, but that existing pattern is
    absolutely horrible.

    Would some enterprising individual please look at making the
    CONFIG_AS_xyz flags use the _real_ config subsystem rather than ad-hoc
    Makefile rules?

    IOW, instead of having

    adx_instr := $(call as-instr,adox %r10$(comma)%r10,-DCONFIG_AS_ADX=1)
    ..
    adx_supported := $(call as-instr,adox %r10$(comma)%r10,yes,no)

    in the makefiles, and silently changing how the Kconfig variables work
    depending on those flags, make that DCONFIG_AS_ADX be a real config
    variable:

    config AS_ADX
    def_bool $(success,$(srctree)/scripts/as-instr.sh "adox %r10,%r10")

    or something like that?

    And then we can make that CRYPTO_CURVE25519_X86 config variable simply have a

    depends on AS_ADX

    in it, and the Kconfig system just takes care of these dependencies on its own.

    Anyway, the crypto change isn't _wrong_, but it does point out an ugly
    little horror in how the crypto layer silently basically changes the
    configuration depending on other things.

    For an example of why this is problematic: it means that if somebody
    sends you their config file, the actual configuration you get may be
    *completely* different from what they actually had, depending on
    tools.

    Added Masahiro to the cc, since he's used to the 'def_bool' model, and
    also is familiar with our existing 'as-instr' Makefile macro.

    So this is basically me throwing out a "I wish somebody would look at
    this". Not meant as a criticism of the commit in question.

    Linus

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