Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Thu, 7 Jan 2021 13:48:36 -0800
From:   Kees Cook <keescook@chromium.org>
To:     Alexander Lobakin <alobakin@pm.me>
Cc:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Arnd Bergmann <arnd@arndb.de>,
        Nathan Chancellor <natechancellor@gmail.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Fangrui Song <maskray@google.com>,
        Huacai Chen <chenhuacai@kernel.org>,
        Pei Huang <huangpei@loongson.cn>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        Ingo Molnar <mingo@kernel.org>,
        Ralf Baechle <ralf@linux-mips.org>,
        Corey Minyard <cminyard@mvista.com>,
        linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arch@vger.kernel.org, stable@vger.kernel.org,
        clang-built-linux@googlegroups.com
Subject: Re: [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation
Message-ID: <202101071348.4BA775344@keescook>
References: <20210107123331.354075-1-alobakin@pm.me>
 <20210107123428.354231-1-alobakin@pm.me>
 <20210107123428.354231-3-alobakin@pm.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210107123428.354231-3-alobakin@pm.me>
Precedence: bulk

On Thu, Jan 07, 2021 at 12:35:01PM +0000, Alexander Lobakin wrote:
> Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added
> -fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler
> from emitting .eh_frame symbols.
> However, as MIPS heavily uses CFI, that's not enough. Use the
> approach taken for x86 (as it also uses CFI) and explicitly put CFI
> symbols into the .debug_frame section (except for VDSO).
> This allows us to drop .eh_frame from DISCARDS as it's no longer
> being generated.
> 
> Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly")
> Suggested-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook