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From:   Brendan Higgins <brendanhiggins@google.com>
Date:   Wed, 15 Jul 2020 01:44:17 -0700
Message-ID: <CAFd5g44Hxhxjqb6WkfaMtaTDKVhs0onnkRaQ0Aq55z6oYTbJbA@mail.gmail.com>
Subject: Re: [PATCH v2 3/3] um: allow static linking for non-glibc implementations
To:     Ignat Korchagin <ignat@cloudflare.com>
Cc:     Jeff Dike <jdike@addtoit.com>, Richard Weinberger <richard@nod.at>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>,
        linux-um <linux-um@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        kernel-team@cloudflare.com
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On Sat, Jul 4, 2020 at 1:52 AM Ignat Korchagin <ignat@cloudflare.com> wrote:
>
> It is possible to produce a statically linked UML binary with UML_NET_VECTOR,
> UML_NET_VDE and UML_NET_PCAP options enabled using alternative libc
> implementations, which do not rely on NSS, such as musl.
>
> Allow static linking in this case.
>
> Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>

One minor issue below. Other than that:

Reviewed-by: Brendan Higgins <brendanhiggins@google.com>

> ---
>  arch/um/Kconfig         | 2 +-
>  arch/um/drivers/Kconfig | 3 ---
>  2 files changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/arch/um/Kconfig b/arch/um/Kconfig
> index 9318dc6d1a0c..af7ed63f9c74 100644
> --- a/arch/um/Kconfig
> +++ b/arch/um/Kconfig
> @@ -67,7 +67,7 @@ config FORBID_STATIC_LINK

Doesn't look like FORBID_STATIC_LINK is used anymore, so you should
probably drop it as well.

With the preceding changes, in this patchset, you can revert my patch
like you did in the RFC - or not, your choice. I am not offended by
people reverting my commits. I just don't like it when people break
allyesconfig. :-)

>  config STATIC_LINK
>         bool "Force a static link"
> -       depends on !FORBID_STATIC_LINK
> +       depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || (!UML_NET_VECTOR && !UML_NET_VDE && !UML_NET_PCAP)
>         help
>           This option gives you the ability to force a static link of UML.
>           Normally, UML is linked as a shared binary.  This is inconvenient for
> diff --git a/arch/um/drivers/Kconfig b/arch/um/drivers/Kconfig
> index 9160ead56e33..72d417055782 100644
> --- a/arch/um/drivers/Kconfig
> +++ b/arch/um/drivers/Kconfig
> @@ -234,7 +234,6 @@ config UML_NET_DAEMON
>  config UML_NET_VECTOR
>         bool "Vector I/O high performance network devices"
>         depends on UML_NET
> -       select FORBID_STATIC_LINK
>         help
>         This User-Mode Linux network driver uses multi-message send
>         and receive functions. The host running the UML guest must have
> @@ -246,7 +245,6 @@ config UML_NET_VECTOR
>  config UML_NET_VDE
>         bool "VDE transport (obsolete)"
>         depends on UML_NET
> -       select FORBID_STATIC_LINK
>         help
>         This User-Mode Linux network transport allows one or more running
>         UMLs on a single host to communicate with each other and also
> @@ -294,7 +292,6 @@ config UML_NET_MCAST
>  config UML_NET_PCAP
>         bool "pcap transport (obsolete)"
>         depends on UML_NET
> -       select FORBID_STATIC_LINK
>         help
>         The pcap transport makes a pcap packet stream on the host look
>         like an ethernet device inside UML.  This is useful for making
> --
> 2.20.1
>