[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <20180626112110.647ff8db@gandalf.local.home>
Date: Tue, 26 Jun 2018 11:21:10 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: Thomas Garnier <thgarnie@...gle.com>
Cc: kernel-hardening@...ts.openwall.com,
Ingo Molnar <mingo@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
James Hogan <jhogan@...nel.org>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>,
nixiaoming <nixiaoming@...wei.com>,
Guenter Roeck <linux@...ck-us.net>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v5 21/27] x86/ftrace: Adapt function tracing for PIE
support
On Mon, 25 Jun 2018 15:39:09 -0700
Thomas Garnier <thgarnie@...gle.com> wrote:
> When using PIE with function tracing, the compiler generates a
> call through the GOT (call *__fentry__@...PCREL). This instruction
> takes 6-bytes instead of 5-bytes with a relative call.
>
> If PIE is enabled, replace the 6th byte of the GOT call by a 1-byte nop
> so ftrace can handle the previous 5-bytes as before.
>
> Position Independent Executable (PIE) support will allow to extend the
> KASLR randomization range 0xffffffff80000000.
>
> Signed-off-by: Thomas Garnier <thgarnie@...gle.com>
Thanks for doing it this way.
Reviewed-by: Steven Rostedt (VMware) <rostedt@...dmis.org>
-- Steve
Powered by blists - more mailing lists