Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Paul Burton <paul.burton@mips.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 <linux-kernel@vger.kernel.org>,
        linux-api <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>,
        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 <shuah@kernel.org>,
        James Hogan <jhogan@kernel.org>,
        Ralf Baechle <ralf@linux-mips.org>,
        linux-mips <linux-mips@linux-mips.org>
Subject: Re: [RFC PATCH for 5.2 10/10] rseq/selftests: mips: use break
 instruction for RSEQ_SIG
Thread-Topic: [RFC PATCH for 5.2 10/10] rseq/selftests: mips: use break
 instruction for RSEQ_SIG
Thread-Index: AQHU+rH+AJnCxtNxUESFNInzrhwEUaZL3nOAYM0M9Xb8+at4gA==
Date:   Wed, 24 Apr 2019 23:17:18 +0000
Message-ID: <20190424231717.os4p6fq7fbx6afxa@pburton-laptop>
References: <20190424152502.14246-1-mathieu.desnoyers@efficios.com>
 <20190424152502.14246-11-mathieu.desnoyers@efficios.com>
 <20190424220609.4kryfcgsv46iu3ds@pburton-laptop>
 <2114325810.1301.1556147523476.JavaMail.zimbra@efficios.com>
In-Reply-To: <2114325810.1301.1556147523476.JavaMail.zimbra@efficios.com>
Accept-Language: en-US
Content-Language: en-US
user-agent: NeoMutt/20180716
x-ms-exchange-messagesentrepresentingtype: 1
x-originating-ip: [67.207.99.198]
x-ms-publictraffictype: Email
x-ms-office365-filtering-correlation-id: 811f4b0f-87b9-474d-778a-08d6c90aff13
x-microsoft-antispam: BCL:0;PCL:0;RULEID:(2390118)(7020095)(4652040)(8989299)(4534185)(4627221)(201703031133081)(201702281549075)(8990200)(5600141)(711020)(4605104)(2017052603328)(7193020);SRVR:MWHPR2201MB1168;
x-ms-traffictypediagnostic: MWHPR2201MB1168:
x-microsoft-antispam-prvs: <MWHPR2201MB1168A3F4FCEE699DD4DBED57C13C0@MWHPR2201MB1168.namprd22.prod.outlook.com>
x-forefront-prvs: 00179089FD
x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(7916004)(136003)(366004)(346002)(396003)(39850400004)(376002)(189003)(199004)(66556008)(14454004)(11346002)(25786009)(3846002)(486006)(316002)(5660300002)(66446008)(6116002)(44832011)(6246003)(476003)(64756008)(54906003)(386003)(256004)(4744005)(4326008)(99286004)(52116002)(446003)(76176011)(58126008)(66476007)(73956011)(2906002)(53936002)(68736007)(186003)(26005)(6506007)(66946007)(1076003)(42882007)(102836004)(71190400001)(66066001)(33716001)(8936002)(7416002)(8676002)(93886005)(81156014)(305945005)(6916009)(97736004)(7736002)(229853002)(478600001)(81166006)(71200400001)(9686003)(6436002)(6486002)(6512007);DIR:OUT;SFP:1102;SCL:1;SRVR:MWHPR2201MB1168;H:MWHPR2201MB1277.namprd22.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1;
received-spf: None (protection.outlook.com: wavecomp.com does not designate
 permitted sender hosts)
x-ms-exchange-senderadcheck: 1
x-microsoft-antispam-message-info: gmg+h0qu0ojPZZOME8OXroHv6vCHsDLgX8V1ND3VEfeatLRrCVBvVF9uhQhHBOc116sqa9zlLPrNyDUVWhk0hTZa1rbwUDhZa1zoFo86gXDCdfu9UDurzQxwiuqKV+EYdizrEgyNBTsLgddg4gGQPcNOvXKvquH9w7RKMCeFtWqgM8CSt0vDrIpp8WZUIBkCh1ma+2a4it5/7MvJ0n6+zAqD/LbDGGj3rr6X1EXe7TsrMefJauJObxNSsEShshZRxsJrG02tznw1qRQ0d7FSW5J0EcvoYUTF6Eie97e7GLv0X9YGTRblxiwStCPd9LnHyLmZD+Ir6+AvkBb1kznRIMqXrki2HizzaPTdozB4yCMA5yZHizl0fybFZ/rXV3O0jUoB0A/WMlpUTB2VUtVfgROF5G/j84I0hp5NloPm0gc=
Content-Type: text/plain; charset="us-ascii"
Content-ID: <A34332AA4ED79447ACBC8144BDE8D8AC@namprd22.prod.outlook.com>
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginatorOrg: mips.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 811f4b0f-87b9-474d-778a-08d6c90aff13
X-MS-Exchange-CrossTenant-originalarrivaltime: 24 Apr 2019 23:17:18.7827
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 463607d3-1db3-40a0-8a29-970c56230104
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR2201MB1168
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi Mathieu,

On Wed, Apr 24, 2019 at 07:12:03PM -0400, Mathieu Desnoyers wrote:
> Does the following comment above the forest of #ifdef work for you ?
>=20
> /*
>  * RSEQ_SIG uses the break instruction. The instruction pattern is:
>  *
>  * On MIPS:
>  *      0350000d        break     0x350
>  *
>  * On nanoMIPS32:
>  *      00100350        break     0x350
>  *
>  * On microMIPS:
>  *      0000d407        break     0x350
>  *
>  * For nanoMIPS32 and microMIPS, the instruction stream is encoded as 16-=
bit
>  * halfwords, so the signature halfwords need to be swapped accordingly f=
or
>  * little-endian.
>  */

I'd probably just say nanoMIPS rather than nanoMIPS32, because when we
get nanoMIPS64 in the future it'll be a superset of nanoMIPS32 & the
break encoding will be the same.

But otherwise it looks good to me :)

Thanks,
    Paul