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emacs 26.3 From: Thiago Jung Bauermann To: Hari Bathini Subject: Re: [PATCH v3 07/12] ppc64/kexec_file: add support to relocate purgatory In-reply-to: <6f64a18a-352e-fdec-c902-45aefc31cc0a@linux.ibm.com> Date: Thu, 16 Jul 2020 19:12:04 -0300 Message-ID: <87365rcdor.fsf@morokweng.localdomain> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235, 18.0.687 definitions=2020-07-16_11:2020-07-16, 2020-07-16 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_spam_definite policy=outbound score=100 lowpriorityscore=0 adultscore=0 clxscore=1015 suspectscore=0 mlxscore=100 bulkscore=0 malwarescore=0 priorityscore=1501 impostorscore=0 phishscore=0 spamscore=100 mlxlogscore=-1000 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2007160142 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: kernel test robot , Pingfan Liu , Petr Tesarik , Nayna Jain , Kexec-ml , Mahesh J Salgaonkar , Mimi Zohar , lkml , linuxppc-dev , Sourabh Jain , Andrew Morton , Dave Young , Vivek Goyal , Eric Biederman Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hari Bathini writes: > On 16/07/20 5:50 am, Thiago Jung Bauermann wrote: >> >> Hari Bathini writes: >> >>> So, add support to relocate purgatory in kexec_file_load system call >>> by setting up TOC pointer and applying RELA relocations as needed. >> >> If we do want to use a C purgatory, Michael Ellerman had suggested >> building it as a Position Independent Executable, which greatly reduces >> the number and types of relocations that are needed. See patches 4 and 9 >> here: >> >> https://lore.kernel.org/linuxppc-dev/1478748449-3894-1-git-send-email-bauerman@linux.vnet.ibm.com/ >> >> In the series above I hadn't converted x86 to PIE. If I had done that, >> possibly Dave Young's opinion would have been different. :-) >> >> If that's still not desirable, he suggested in that discussion lifting >> some code from x86 to generic code, which I implemented and would >> simplify this patch as well: >> >> https://lore.kernel.org/linuxppc-dev/5009580.5GxAkTrMYA@morokweng/ >> > > Agreed. But I prefer to work on PIE and/or moving common relocation_add code > for x86 & s390 to generic code later when I try to build on these purgatory > changes. So, a separate series later to rework purgatory with the things you > mentioned above sounds ok? Sounds ok to me. Let's see what the maintainers think, then. -- Thiago Jung Bauermann IBM Linux Technology Center