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Wed, 29 Jul 2026 08:13:12 +0000 (GMT) Received: from [9.39.24.31] (unknown [9.39.24.31]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 29 Jul 2026 08:13:11 +0000 (GMT) Message-ID: <93bd50eb-0205-4ed6-a3cb-a29bda61db3d@linux.ibm.com> Date: Wed, 29 Jul 2026 13:43:10 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] ppc/fadump: collect dump if the collected size is lesser than reserved To: Shivang Upadhyay , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Cc: maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, adri.vero.dev@gmail.com, adityag@linux.ibm.com, anushree.mathur@linux.vnet.ibm.com References: <20260714173010.615682-1-shivangu@linux.ibm.com> <446c84c2-8639-4ecb-8a46-1e203a166e46@linux.ibm.com> <72589eca-2e97-4a2f-8665-b2a817a04722@linux.ibm.com> <7618bf3e48f6770a803f8350d0b3b084c23042fa.camel@linux.ibm.com> <7eb8ed5f-0652-4675-9369-913a17463093@linux.ibm.com> <4e7bd9342efa0cbdd162445a994f73c9ad473645.camel@linux.ibm.com> Content-Language: en-US From: Sourabh Jain In-Reply-To: <4e7bd9342efa0cbdd162445a994f73c9ad473645.camel@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: mTZGkNDAx-goU1ZEh5ucpLvuSerr5FDU X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzI5MDA2MiBTYWx0ZWRfXwBQ/+rIjHgC8 xN95o8x1WRiFxG7QtgbHqOo5MIVEV3t+wyTK7KudPOZ9Xmp5uAJmL7cY5thyZTjGYbBevMqrLpr TOR9VohSRLQH17Vic4m4kTNh+N82oax2XXrk2bZvvf+2JKLZlFMRKC6hu+/Co8LLrSHBzrI4OkG Mdb7E6I6YaQOxhaELHelwH9xmVZFGcLgBCrkgTq155rsTMRdT6+Hd7J4hi7qcac/VNVyBc02M0o e/v07YSdrZm15eIoMcOeXwk5vGOZ2rnpBu9AesoLHKsXF1cxIcXeN6UK65RVzzxHs8P5PPLQN9w gA6BNgqf2YKNXm265cjo0p7wKNlQbXsoFHXuN7OZUmjNzMv01pc7kUecyP+NpxX6+W3/iZLKs+c xcuqUYuX2ZqEOeMx4ZiHQVZR53tj4pC/cLsOvc7ApHBwE9BFdbRfwAueh7L2CrdWB1ZaQL3D/1C DRpC7GYtmT6eHyShFdA== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzI5MDA2MiBTYWx0ZWRfX/i+jWj2Cxuzc 7LNQiB4V9c0sGMVbIeyTAt2BwV6Er7xvqYjINVrQzp/VI3wfDCunbn9vaa2MTqXIYRAqIKDAfvg iQvy0Wi1Clc63lRJ/CFHnd/GDZEAMP4= X-Authority-Analysis: v=2.4 cv=AZeB2XXG c=1 sm=1 tr=0 ts=6a69b620 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=kwF1vnAZszKunuOjKt0A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: aXKBVhE0eoDwHzGaPdcNSIgQJIZfZSyP X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-29_03,2026-07-28_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 priorityscore=1501 phishscore=0 adultscore=0 impostorscore=0 clxscore=1015 malwarescore=0 suspectscore=0 lowpriorityscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607290062 On 29/07/26 12:30, Shivang Upadhyay wrote: > On Wed, 2026-07-29 at 11:58 +0530, Sourabh Jain wrote: >>> Yes, I made it this way by reading the dump_bytes and source_len >>> relation. PAPR only says that dumped_bytes should not exceed the >>> source_len. My change reflects the same restriction in sw. Also >>> along >>> with this lengths check, we have firmware reported error flag also, >>> which should take care of overflow (Qemu handles it like this [1]). >> But the firmware not copying the entire Real Mode memory is also a >> problem for >> the kernel, isn't it? >> > I think it should be fine. Firmware will report it status flags, right? I don't know. Does PAPR says anything about the error code corresponds to when memory to not copied completely? > There are these valid flag values. > > Dump Error Flags (set by platform) > Bit mask > 0x8000 = Invalid section data type > 0x4000 = Invalid source address > 0x2000 = Requested section length exceeds source > 0x1000 = Invalid partition destination address > 0x0800 = Partition memory destination too small