Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230407070517.204676-1-andrea.righi@canonical.com>
In-Reply-To: <20230407070517.204676-1-andrea.righi@canonical.com>
From:   Eric Curtin <ecurtin@redhat.com>
Date:   Sat, 8 Apr 2023 11:24:41 +0100
Message-ID: <CAOgh=FxE_Y3Chr3wCG5QkoPZW5-BjrVCM9moEZGy=xMkv2fKOA@mail.gmail.com>
Subject: Re: [PATCH] scripts: rust: drop is_rust_module.sh
To:     Andrea Righi <andrea.righi@canonical.com>
Cc:     Miguel Ojeda <ojeda@kernel.org>,
        Alex Gaynor <alex.gaynor@gmail.com>,
        Wedson Almeida Filho <wedsonaf@gmail.com>,
        Boqun Feng <boqun.feng@gmail.com>, Gary Guo <gary@garyguo.net>,
        =?UTF-8?Q?Bj=C3=B6rn_Roy_Baron?= <bjorn3_gh@protonmail.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>, Tom Rix <trix@redhat.com>,
        Martin Rodriguez Reboredo <yakoyoku@gmail.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Neal Gompa <neal@gompa.dev>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        rust-for-linux@vger.kernel.org, linux-kbuild@vger.kernel.org,
        llvm@lists.linux.dev, linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, 7 Apr 2023 at 08:05, Andrea Righi <andrea.righi@canonical.com> wrote:
>
> Commit c1177979af9c ("btf, scripts: Exclude Rust CUs with pahole")
> introduced the constraint "!DEBUG_INFO_BTF || PAHOLE_HAS_LANG_EXCLUDE"
> to enable RUST.
>
> With this constraint we don't need is_rust_module.sh anymore, because
> 'pahole --lang_exclude=rust' already has the capability to exclude Rust
> CUs. If pahole isn't recent enough (< 1.24) to support --lang_exclude,
> then DEBUG_INFO_BTF can't be enabled with RUST and is_rust_module.sh
> isn't used as well.
>
> In any case is_rust_module.sh is obsolete and we can just drop it.
>
> Link: https://lore.kernel.org/lkml/Y+p2xKIN6TJnQinK@righiandr-XPS-13-7390/
> Signed-off-by: Andrea Righi <andrea.righi@canonical.com>

Ran this in an Asahi Fedora build to be sure.

Tested-by: Eric Curtin <ecurtin@redhat.com>
Reviewed-by: Eric Curtin <ecurtin@redhat.com>

Is mise le meas/Regards,

Eric Curtin

> ---
>  rust/macros/module.rs     |  2 +-
>  scripts/Makefile.modfinal |  2 --
>  scripts/is_rust_module.sh | 16 ----------------
>  3 files changed, 1 insertion(+), 19 deletions(-)
>  delete mode 100755 scripts/is_rust_module.sh
>
> diff --git a/rust/macros/module.rs b/rust/macros/module.rs
> index a7e363c2b044..608406f33a70 100644
> --- a/rust/macros/module.rs
> +++ b/rust/macros/module.rs
> @@ -179,7 +179,7 @@ pub(crate) fn module(ts: TokenStream) -> TokenStream {
>              /// Used by the printing macros, e.g. [`info!`].
>              const __LOG_PREFIX: &[u8] = b\"{name}\\0\";
>
> -            /// The \"Rust loadable module\" mark, for `scripts/is_rust_module.sh`.
> +            /// The \"Rust loadable module\" mark.
>              //
>              // This may be best done another way later on, e.g. as a new modinfo
>              // key or a new section. For the moment, keep it simple.
> diff --git a/scripts/Makefile.modfinal b/scripts/Makefile.modfinal
> index 4703f652c009..e6f8fa3c9b8d 100644
> --- a/scripts/Makefile.modfinal
> +++ b/scripts/Makefile.modfinal
> @@ -41,8 +41,6 @@ quiet_cmd_btf_ko = BTF [M] $@
>        cmd_btf_ko =                                                     \
>         if [ ! -f vmlinux ]; then                                       \
>                 printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
> -       elif [ -n "$(CONFIG_RUST)" ] && $(srctree)/scripts/is_rust_module.sh $@; then           \
> -               printf "Skipping BTF generation for %s because it's a Rust module\n" $@ 1>&2; \
>         else                                                            \
>                 LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J $(PAHOLE_FLAGS) --btf_base vmlinux $@; \
>                 $(RESOLVE_BTFIDS) -b vmlinux $@;                        \
> diff --git a/scripts/is_rust_module.sh b/scripts/is_rust_module.sh
> deleted file mode 100755
> index 28b3831a7593..000000000000
> --- a/scripts/is_rust_module.sh
> +++ /dev/null
> @@ -1,16 +0,0 @@
> -#!/bin/sh
> -# SPDX-License-Identifier: GPL-2.0
> -#
> -# is_rust_module.sh module.ko
> -#
> -# Returns `0` if `module.ko` is a Rust module, `1` otherwise.
> -
> -set -e
> -
> -# Using the `16_` prefix ensures other symbols with the same substring
> -# are not picked up (even if it would be unlikely). The last part is
> -# used just in case LLVM decides to use the `.` suffix.
> -#
> -# In the future, checking for the `.comment` section may be another
> -# option, see https://github.com/rust-lang/rust/pull/97550.
> -${NM} "$*" | grep -qE '^[0-9a-fA-F]+ r _R[^[:space:]]+16___IS_RUST_MODULE[^[:space:]]*$'
> --
> 2.39.2
>