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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Fri, 7 Jun 2019 07:47:10 +0100 Received: from b01ledav002.gho.pok.ibm.com (b01ledav002.gho.pok.ibm.com [9.57.199.107]) by b01cxnp23034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x576l9Ts37093632 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 7 Jun 2019 06:47:09 GMT Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 69B55124052; Fri, 7 Jun 2019 06:47:09 +0000 (GMT) Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B7BB2124055; Fri, 7 Jun 2019 06:47:07 +0000 (GMT) Received: from skywalker.in.ibm.com (unknown [9.124.35.207]) by b01ledav002.gho.pok.ibm.com (Postfix) with ESMTP; Fri, 7 Jun 2019 06:47:07 +0000 (GMT) From: "Aneesh Kumar K.V" To: npiggin@gmail.com, paulus@samba.org, mpe@ellerman.id.au, oohall@gmail.com Subject: [PATCH] powerpc/scm: Use a specific endian format for storing uuid from the device tree Date: Fri, 7 Jun 2019 12:17:05 +0530 X-Mailer: git-send-email 2.21.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19060706-0064-0000-0000-000003EB0F74 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011227; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01214407; UDB=6.00638362; IPR=6.00995492; MB=3.00027216; MTD=3.00000008; XFM=3.00000015; UTC=2019-06-07 06:47:11 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19060706-0065-0000-0000-00003DC9A67D Message-Id: <20190607064705.29043-1-aneesh.kumar@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-06-07_03:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906070048 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Aneesh Kumar K.V" , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" We used uuid_parse to convert uuid string from device tree to two u64 components. We want to make sure we look at the uuid read from device tree in an endian-neutral fashion. For now, I am picking little-endian to be format so that we don't end up doing an additional conversion. The reason to store in a specific endian format is to enable reading the namespace created with a little-endian kernel config on a big-endian kernel. We do store the device tree uuid string as a 64-bit little-endian cookie in the label area. When booting the kernel we also compare this cookie against what is read from the device tree. For this, to work we have to store and compare these values in a CPU endian config independent fashion. Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/platforms/pseries/papr_scm.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c index 80fbab118ef1..c8ec670ee924 100644 --- a/arch/powerpc/platforms/pseries/papr_scm.c +++ b/arch/powerpc/platforms/pseries/papr_scm.c @@ -373,8 +373,15 @@ static int papr_scm_probe(struct platform_device *pdev) /* We just need to ensure that set cookies are unique across */ uuid_parse(uuid_str, (uuid_t *) uuid); - p->nd_set.cookie1 = uuid[0]; - p->nd_set.cookie2 = uuid[1]; + /* + * cookie1 and cookie2 are not really little endian + * we store a little endian representation of the + * uuid str so that we can compare this with the label + * area cookie irrespective of the endian config with which + * the kernel is built. + */ + p->nd_set.cookie1 = cpu_to_le64(uuid[0]); + p->nd_set.cookie2 = cpu_to_le64(uuid[1]); /* might be zero */ p->metadata_size = metadata_size; -- 2.21.0