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Rao" Subject: Re: [PATCH 2/2] recordmcount: Handle sections with no non-weak symbols To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, llvm@lists.linux.dev, Michael Ellerman , Nathan Chancellor , Nick Desaulniers References: <1b9566f0e7185fb8fd8ef2535add7a081501ccc8.1651047542.git.naveen.n.rao@linux.vnet.ibm.com> <20220427095415.594e5120@gandalf.local.home> <1651129169.fpixr00hgx.naveen@linux.ibm.com> <20220428100602.7b215e52@gandalf.local.home> In-Reply-To: <20220428100602.7b215e52@gandalf.local.home> MIME-Version: 1.0 User-Agent: astroid/4d6b06ad (https://github.com/astroidmail/astroid) Message-Id: <1651166416.afl3n7tts7.naveen@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: V_3oPaqbt0Lmd6t9nEDoUpTU-Us_FpBk X-Proofpoint-GUID: px6PpEwvTf_aBfqjrNlCpkEXQo8w50Kq X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-04-28_02,2022-04-28_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 lowpriorityscore=0 phishscore=0 spamscore=0 mlxlogscore=495 clxscore=1015 impostorscore=0 priorityscore=1501 suspectscore=0 mlxscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2204280103 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Steven Rostedt wrote: > On Thu, 28 Apr 2022 13:15:22 +0530 > "Naveen N. Rao" wrote: >=20 >> Indeed, plain old -pg will be a problem. I'm not sure there is a generic= =20 >> way to address this. I suppose architectures will have to validate the=20 >> mcount locations, something like this? >=20 > Perhaps another solution is to make the mcount locations after the linkin= g > is done. The main downside to that is that it takes time to go over the > entire vmlinux, and will slow down a compile that only modified a couple = of > files. Yes, and I think that is also very useful with LTO. So, that would be a=20 good one to consider in the longer term. For now, I have posted a v2 of this series with your comments addressed. =20 It is working well in my tests on powerpc in the different=20 configurations, including the older elf abi v1 that uses -pg. If it=20 looks ok to you, we can use this approach for now. Thanks, Naveen