From: Kees Cook <keescook@chromium.org>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Thomas Lendacky <Thomas.Lendacky@amd.com>,
Sami Tolvanen <samitolvanen@google.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H . Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: Re: [PATCH] x86: Don't discard .exit.text and .exit.data at link-time
Date: Thu, 30 Jan 2020 11:40:44 -0800 [thread overview]
Message-ID: <202001301139.F8859A4@keescook> (raw)
In-Reply-To: <20200130180048.2901-1-hjl.tools@gmail.com>
On Thu, Jan 30, 2020 at 10:00:48AM -0800, H.J. Lu wrote:
> Since .exit.text and .exit.data sections are discarded at runtime, we
> should undefine EXIT_TEXT and EXIT_DATA to exclude .exit.text and
> .exit.data sections from default discarded sections.
This is just a correctness fix, yes? The EXIT_TEXT and EXIT_DATA were
already included before the /DISCARD/ section here, so there's no
behavioral change with this patch, correct?
-Kees
>
> Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
> ---
> arch/x86/kernel/vmlinux.lds.S | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
> index d1b942365d27..fb2c45cb1d1f 100644
> --- a/arch/x86/kernel/vmlinux.lds.S
> +++ b/arch/x86/kernel/vmlinux.lds.S
> @@ -416,6 +416,12 @@ SECTIONS
> STABS_DEBUG
> DWARF_DEBUG
>
> + /* Sections to be discarded. EXIT_TEXT and EXIT_DATA discard at runtime.
> + * not link time. */
> +#undef EXIT_TEXT
> +#define EXIT_TEXT
> +#undef EXIT_DATA
> +#define EXIT_DATA
> DISCARDS
> /DISCARD/ : {
> *(.eh_frame)
> --
> 2.24.1
>
--
Kees Cook
next prev parent reply other threads:[~2020-01-30 19:40 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-30 18:00 [PATCH] x86: Don't discard .exit.text and .exit.data at link-time H.J. Lu
2020-01-30 19:40 ` Kees Cook [this message]
2020-01-30 19:45 ` H.J. Lu
2020-01-30 19:58 ` Kees Cook
2020-01-30 20:06 ` H.J. Lu
2020-01-30 20:47 ` [PATCH] Add RUNTIME_DISCARD_EXIT to generic DISCARDS H.J. Lu
2020-01-30 22:04 ` Kees Cook
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