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From: Joseph Myers <joseph@codesourcery.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Will Deacon <will.deacon@arm.com>, carlos <carlos@redhat.com>,
	Florian Weimer <fweimer@redhat.com>,
	Szabolcs Nagy <szabolcs.nagy@arm.com>,
	libc-alpha <libc-alpha@sourceware.org>,
	Thomas Gleixner <tglx@linutronix.de>, Ben Maurer <bmaurer@fb.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Dave Watson <davejwatson@fb.com>, Paul Turner <pjt@google.com>,
	Rich Felker <dalias@libc.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	linux-api <linux-api@vger.kernel.org>
Subject: Re: [PATCH 1/5] glibc: Perform rseq(2) registration at C startup and thread creation (v8)
Date: Thu, 18 Apr 2019 14:48:34 +0000	[thread overview]
Message-ID: <alpine.DEB.2.21.1904181445550.5356@digraph.polyomino.org.uk> (raw)
In-Reply-To: <1066731871.915.1555593471194.JavaMail.zimbra@efficios.com>

On Thu, 18 Apr 2019, Mathieu Desnoyers wrote:

> The approach above should work for arm32 be8 vs be32 linker weirdness.
> 
> For aarch64, I think we can simply do:
> 
> /*
>  * 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 __ARM_BIG_ENDIAN
> #define RSEQ_SIG_DATA   0x00bc28d4      /* BRK #0x45E0.  */
> #else
> #define RSEQ_SIG_DATA   RSEQ_SIG_CODE
> #endif
> 
> #define RSEQ_SIG        RSEQ_SIG_DATA
> 
> Feedback is most welcome,

You'll also need __ASSEMBLER__ conditionals in the installed sys/rseq.h 
header so that it only defines constants and doesn't include any C 
declarations in that case, if RSEQ_SIG_CODE is meant to be usable in .S 
files rather than just inline asm in C files.

-- 
Joseph S. Myers
joseph@codesourcery.com

  reply	other threads:[~2019-04-18 14:48 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190416173216.9028-1-mathieu.desnoyers@efficios.com>
2019-04-16 17:32 ` [PATCH 1/5] glibc: Perform rseq(2) registration at C startup and thread creation (v8) Mathieu Desnoyers
2019-04-17 15:59   ` Mathieu Desnoyers
2019-04-17 16:17     ` Joseph Myers
2019-04-17 19:56       ` Mathieu Desnoyers
2019-04-18 13:17         ` Mathieu Desnoyers
2019-04-18 14:48           ` Joseph Myers [this message]
2019-04-18 15:37             ` Mathieu Desnoyers
2019-04-18 15:33           ` Szabolcs Nagy
2019-04-18 15:41             ` Mathieu Desnoyers
2019-04-18 16:07               ` Szabolcs Nagy
2019-04-18 17:10                 ` Mathieu Desnoyers
2019-04-18 17:37                   ` Szabolcs Nagy
2019-04-18 18:17                     ` Mathieu Desnoyers
2019-04-23 11:16                       ` Szabolcs Nagy
2019-04-23 11:59                         ` Ramana Radhakrishnan
2019-04-23 12:36                           ` Mathieu Desnoyers
2019-04-16 17:32 ` [PATCH 2/5] glibc: sched_getcpu(): use rseq cpu_id TLS on Linux (v2) Mathieu Desnoyers
2019-04-18 15:33   ` Szabolcs Nagy
2019-04-18 15:45     ` Mathieu Desnoyers

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