From: Will Deacon <will.deacon@arm.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Andy Lutomirski <luto@amacapital.net>,
Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Russell King <linux@arm.linux.org.uk>,
Ingo Molnar <mingo@redhat.com>, "H . Peter Anvin" <hpa@zytor.com>,
Andi Kleen <andi@firstfloor.org>, Chris Lameter <cl@linux.com>,
Ben Maurer <bmaurer@fb.com>, Steven Rostedt <rostedt@goodmis.org>,
Josh Triplett <josh@joshtriplett.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Joel Fernandes <joelaf@google.com>, Shuah Khan <shuah@kernel.org>,
linux-kselftest@vger.kernel.org
Subject: Re: [RFC PATCH for 5.2 08/10] rseq/selftests: aarch64 code signature: handle big-endian environment
Date: Wed, 24 Apr 2019 17:45:38 +0100 [thread overview]
Message-ID: <20190424164538.GC18611@fuggles.cambridge.arm.com> (raw)
In-Reply-To: <20190424152502.14246-9-mathieu.desnoyers@efficios.com>
On Wed, Apr 24, 2019 at 11:25:00AM -0400, Mathieu Desnoyers wrote:
> Handle compiling with -mbig-endian on aarch64, which generates binaries
> with mixed code vs data endianness (little endian code, big endian
> data).
>
> Else mismatch between code endianness for the generated signatures and
> data endianness for the RSEQ_SIG parameter passed to the rseq
> registration will trigger application segmentation faults when the
> kernel try to abort rseq critical sections.
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> CC: Peter Zijlstra <peterz@infradead.org>
> CC: Thomas Gleixner <tglx@linutronix.de>
> CC: Joel Fernandes <joelaf@google.com>
> CC: Catalin Marinas <catalin.marinas@arm.com>
> CC: Dave Watson <davejwatson@fb.com>
> CC: Will Deacon <will.deacon@arm.com>
> CC: Shuah Khan <shuah@kernel.org>
> CC: Andi Kleen <andi@firstfloor.org>
> CC: linux-kselftest@vger.kernel.org
> CC: "H . Peter Anvin" <hpa@zytor.com>
> CC: Chris Lameter <cl@linux.com>
> CC: Russell King <linux@arm.linux.org.uk>
> CC: Michael Kerrisk <mtk.manpages@gmail.com>
> CC: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>
> CC: Paul Turner <pjt@google.com>
> CC: Boqun Feng <boqun.feng@gmail.com>
> CC: Josh Triplett <josh@joshtriplett.org>
> CC: Steven Rostedt <rostedt@goodmis.org>
> CC: Ben Maurer <bmaurer@fb.com>
> CC: linux-api@vger.kernel.org
> CC: Andy Lutomirski <luto@amacapital.net>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: Linus Torvalds <torvalds@linux-foundation.org>
> ---
> tools/testing/selftests/rseq/rseq-arm64.h | 17 +++++++++++++++--
> 1 file changed, 15 insertions(+), 2 deletions(-)
>
> diff --git a/tools/testing/selftests/rseq/rseq-arm64.h b/tools/testing/selftests/rseq/rseq-arm64.h
> index b41a2a48e965..200dae9e4208 100644
> --- a/tools/testing/selftests/rseq/rseq-arm64.h
> +++ b/tools/testing/selftests/rseq/rseq-arm64.h
> @@ -6,7 +6,20 @@
> * (C) Copyright 2018 - Will Deacon <will.deacon@arm.com>
> */
>
> -#define RSEQ_SIG 0xd428bc00 /* BRK #0x45E0 */
> +/*
> + * aarch64 -mbig-endian generates mixed endianness code vs data:
> + * little-endian code and big-endian data. Ensure the RSEQ_SIG signature
> + * matches code endianness.
> + */
> +#define RSEQ_SIG_CODE 0xd428bc00 /* BRK #0x45E0. */
> +
> +#ifdef __AARCH64EB__
> +#define RSEQ_SIG_DATA 0x00bc28d4 /* BRK #0x45E0. */
It would be neater to implement swab32 and use that with RSEQ_SIG_CODE,
but either way:
Acked-by: Will Deacon <will.deacon@arm.com>
Will
next prev parent reply other threads:[~2019-04-24 16:45 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-24 15:24 [RFC PATCH for 5.2 00/10] Restartable Sequences selftests updates Mathieu Desnoyers
2019-04-24 15:24 ` [RFC PATCH for 5.2 01/10] rseq/selftests: Add __rseq_exit_point_array section for debuggers Mathieu Desnoyers
2019-04-24 15:24 ` [RFC PATCH for 5.2 02/10] rseq/selftests: Introduce __rseq_cs_ptr_array, rename __rseq_table to __rseq_cs Mathieu Desnoyers
2019-04-24 15:24 ` [RFC PATCH for 5.2 03/10] rseq/selftests: Use __rseq_handled symbol to coexist with glibc Mathieu Desnoyers
2019-04-24 15:24 ` [RFC PATCH for 5.2 04/10] rseq/selftests: s390: use jg instruction for jumps outside of the asm Mathieu Desnoyers
2019-04-24 15:24 ` [RFC PATCH for 5.2 05/10] rseq/selftests: x86: use ud1 instruction as RSEQ_SIG opcode Mathieu Desnoyers
2019-04-24 15:24 ` [RFC PATCH for 5.2 06/10] rseq/selftests: s390: use trap4 for RSEQ_SIG Mathieu Desnoyers
2019-04-24 15:24 ` [RFC PATCH for 5.2 07/10] rseq/selftests: arm: use udf instruction " Mathieu Desnoyers
2019-04-24 15:25 ` [RFC PATCH for 5.2 08/10] rseq/selftests: aarch64 code signature: handle big-endian environment Mathieu Desnoyers
2019-04-24 16:40 ` Mark Rutland
2019-04-24 16:44 ` Will Deacon
2019-04-24 16:45 ` Mark Rutland
2019-04-24 16:45 ` Will Deacon [this message]
2019-04-24 16:51 ` Mark Rutland
2019-04-24 17:00 ` Mathieu Desnoyers
2019-04-24 17:02 ` Mathieu Desnoyers
2019-04-24 15:25 ` [RFC PATCH for 5.2 09/10] rseq/selftests: powerpc code signature: generate valid instructions Mathieu Desnoyers
2019-04-24 15:25 ` [RFC PATCH for 5.2 10/10] rseq/selftests: mips: use break instruction for RSEQ_SIG Mathieu Desnoyers
2019-04-24 22:06 ` Paul Burton
2019-04-24 23:12 ` Mathieu Desnoyers
2019-04-24 23:17 ` Paul Burton
2019-04-24 23:22 ` Mathieu Desnoyers
2019-04-25 14:21 ` Mathieu Desnoyers
2019-04-29 22:31 ` Paul Burton
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190424164538.GC18611@fuggles.cambridge.arm.com \
--to=will.deacon@arm.com \
--cc=akpm@linux-foundation.org \
--cc=andi@firstfloor.org \
--cc=bmaurer@fb.com \
--cc=boqun.feng@gmail.com \
--cc=catalin.marinas@arm.com \
--cc=cl@linux.com \
--cc=davejwatson@fb.com \
--cc=hpa@zytor.com \
--cc=joelaf@google.com \
--cc=josh@joshtriplett.org \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux@arm.linux.org.uk \
--cc=luto@amacapital.net \
--cc=mathieu.desnoyers@efficios.com \
--cc=mingo@redhat.com \
--cc=mtk.manpages@gmail.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
--cc=pjt@google.com \
--cc=rostedt@goodmis.org \
--cc=shuah@kernel.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).