From: Kees Cook <keescook@chromium.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Yinan Liu <yinan@linux.alibaba.com>,
Steven Rostedt <rostedt@goodmis.org>,
linuxppc-dev@lists.ozlabs.org,
Sachin Sant <sachinp@linux.ibm.com>,
linux-kernel@vger.kernel.org, ardb@kernel.org
Subject: Re: [powerpc] ftrace warning kernel/trace/ftrace.c:2068 with code-patching selftests
Date: Thu, 27 Jan 2022 08:41:38 -0800 [thread overview]
Message-ID: <202201270834.4420E21F6@keescook> (raw)
In-Reply-To: <YfKGKWW5UfZ15kCW@FVFF77S0Q05N>
On Thu, Jan 27, 2022 at 11:46:49AM +0000, Mark Rutland wrote:
> I'm not sure how x86 works here; AFAICT the relocations are performed during
> decompression, but it looks like there's some special build-time processing
> associated with that, and the vmlinux doesn't contain standard ELF relocations.
>
> Kees, IIUC you added the x86_64 support there, can you shed any light on if/how
> this works on x86?
I think Sven beat me to it, and this was answered in
https://lore.kernel.org/lkml/yt9dy231gzae.fsf@linux.ibm.com
but let me know if anything needs further info.
An additional note is that x86 is built with "-2G addressing"
(-mcmodel=kernel). There was some work done to make it actually
PIE, which would allow the KASLR base to move further:
https://github.com/KSPP/linux/issues/38
-Kees
--
Kees Cook
prev parent reply other threads:[~2022-01-27 16:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-24 9:19 [powerpc] ftrace warning kernel/trace/ftrace.c:2068 with code-patching selftests Sachin Sant
[not found] ` <e9422643-a210-b77f-a037-da63a9d2e925@linux.alibaba.com>
[not found] ` <20220124114548.30241947@gandalf.local.home>
[not found] ` <0fa0daec-881a-314b-e28b-3828e80bbd90@linux.alibaba.com>
[not found] ` <YfFclROd+0/61q2d@FVFF77S0Q05N>
2022-01-27 11:46 ` Mark Rutland
2022-01-27 12:03 ` Ard Biesheuvel
2022-01-27 12:20 ` Mark Rutland
2022-01-27 12:22 ` Ard Biesheuvel
2022-01-27 12:59 ` Mark Rutland
2022-01-27 13:07 ` Ard Biesheuvel
2022-01-27 13:24 ` Mark Rutland
2022-01-27 13:59 ` Ard Biesheuvel
2022-01-27 14:54 ` Mark Rutland
2022-01-27 15:01 ` Ard Biesheuvel
2022-01-27 12:04 ` Sven Schnelle
2022-01-27 12:27 ` Mark Rutland
2022-01-27 12:46 ` Steven Rostedt
2022-01-27 13:08 ` Mark Rutland
2022-01-27 13:16 ` Sven Schnelle
2022-01-27 13:33 ` Mark Rutland
2022-01-27 13:55 ` Steven Rostedt
2022-01-27 14:56 ` Mark Rutland
2022-01-27 16:41 ` Kees Cook [this message]
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