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Rao" , Christophe Leroy , Vasily Gorbik , Jiri Kosina , Joe Lawrence , Josh Poimboeuf , Miroslav Benes , Ingo Molnar , Michael Ellerman , Petr Mladek , Steven Rostedt , "linux-kernel@vger.kernel.org" , "linux-s390@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "live-patching@vger.kernel.org" Subject: Re: [PATCH v2 09/13] powerpc/ftrace: Implement CONFIG_DYNAMIC_FTRACE_WITH_ARGS References: <5831f711a778fcd6eb51eb5898f1faae4378b35b.1640017960.git.christophe.leroy@csgroup.eu> <1644852011.qg7ud9elo2.naveen@linux.ibm.com> <1b28f52a-f8b7-6b5c-e726-feac4123517d@csgroup.eu> <875ypgo0f3.fsf@mpe.ellerman.id.au> <1644930705.g64na2kgvd.naveen@linux.ibm.com> <6dc50f09-4d14-afa2-d2a1-34b72b880edf@csgroup.eu> <5c7b5334-6071-f131-a509-9a49ca3d628c@csgroup.eu> <1644941712.lqdstzo09z.naveen@linux.ibm.com> Date: Wed, 16 Feb 2022 14:27:09 +0100 In-Reply-To: (Heiko Carstens's message of "Wed, 16 Feb 2022 14:04:18 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 4P13vTTY8jUoKkrC9N3P8RbRIK8AStlA X-Proofpoint-ORIG-GUID: Rv68b89V4IpwCICup99AtZAzo4shCls4 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.816,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2022-02-16_06,2022-02-16_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 spamscore=0 clxscore=1011 impostorscore=0 lowpriorityscore=0 phishscore=0 suspectscore=0 mlxlogscore=764 priorityscore=1501 malwarescore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2202160076 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Heiko Carstens writes: > So, the in both variants s390 provides nearly identical data. The only > difference is that for FL_SAVE_REGS the program status word mask is > missing; therefore it is not possible to figure out the condition code > or if interrupts were enabled/disabled. > > Vasily, Sven, I think we have two options here: > > - don't provide sane psw mask contents at all and say (again) that > ptregs contents are identical > > - provide (finally) a full psw mask contents using epsw, and indicate > validity with a flags bit in pt_regs > > I would vote for the second option, even though epsw is slow. But this > is about the third or fourth time this came up in different > contexts. So I'd guess we should go for the slow but complete > solution. Opinions? Given that this only affects ftrace_regs_caller, i would also vote for the second option.