From: Mark Rutland <mark.rutland@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>,
Will Deacon <will.deacon@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 17:45:37 +0100 [thread overview]
Message-ID: <20190424164536.GE21101@lakrids.cambridge.arm.com> (raw)
In-Reply-To: <20190424164032.GD21101@lakrids.cambridge.arm.com>
On Wed, Apr 24, 2019 at 05:40:33PM +0100, Mark Rutland wrote:
> On Wed, Apr 24, 2019 at 11:25:00AM -0400, Mathieu Desnoyers wrote:
> > +/*
> > + * 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. */
> > +#else
> > +#define RSEQ_SIG_DATA RSEQ_SIG_CODE
> > +#endif
> > +
> > +#define RSEQ_SIG RSEQ_SIG_DATA
> >
> > #define rseq_smp_mb() __asm__ __volatile__ ("dmb ish" ::: "memory")
> > #define rseq_smp_rmb() __asm__ __volatile__ ("dmb ishld" ::: "memory")
> > @@ -121,7 +134,7 @@ do { \
> >
> > #define RSEQ_ASM_DEFINE_ABORT(label, abort_label) \
> > " b 222f\n" \
> > - " .inst " __rseq_str(RSEQ_SIG) "\n" \
> > + " .inst " __rseq_str(RSEQ_SIG_CODE) "\n" \
>
> I don't think this is right; the .inst directive _should_ emit the value
> in the instruction stream endianness (i.e. LE, regardless of the data
> endianness).
Now I see the RSEQ_CODE value isn't endian-swapped as teh RSEQ_DATA
value is, so the code above is fine.
Sory for the noise.
Thanks,
Mark.
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 [this message]
2019-04-24 16:45 ` Will Deacon
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
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