{"id":814192,"url":"http://patchwork.ozlabs.org/api/1.2/patches/814192/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20170915100821.7254-1-naveen.n.rao@linux.vnet.ibm.com/","project":{"id":2,"url":"http://patchwork.ozlabs.org/api/1.2/projects/2/?format=json","name":"Linux PPC development","link_name":"linuxppc-dev","list_id":"linuxppc-dev.lists.ozlabs.org","list_email":"linuxppc-dev@lists.ozlabs.org","web_url":"https://github.com/linuxppc/wiki/wiki","scm_url":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git","webscm_url":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/","list_archive_url":"https://lore.kernel.org/linuxppc-dev/","list_archive_url_format":"https://lore.kernel.org/linuxppc-dev/{}/","commit_url_format":"https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id={}"},"msgid":"<20170915100821.7254-1-naveen.n.rao@linux.vnet.ibm.com>","list_archive_url":"https://lore.kernel.org/linuxppc-dev/20170915100821.7254-1-naveen.n.rao@linux.vnet.ibm.com/","date":"2017-09-15T10:08:21","name":"powerpc/kprobes: Update optprobes to use emulate_update_regs()","commit_ref":"8afafa6fba7809c0785018b77c95b19e58b35b94","pull_url":null,"state":"accepted","archived":false,"hash":"2c1f735f851dc3be321739e31131c10769a4c5c5","submitter":{"id":15185,"url":"http://patchwork.ozlabs.org/api/1.2/people/15185/?format=json","name":"Naveen N. Rao","email":"naveen.n.rao@linux.vnet.ibm.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linuxppc-dev/patch/20170915100821.7254-1-naveen.n.rao@linux.vnet.ibm.com/mbox/","series":[{"id":3263,"url":"http://patchwork.ozlabs.org/api/1.2/series/3263/?format=json","web_url":"http://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=3263","date":"2017-09-15T10:08:21","name":"powerpc/kprobes: Update optprobes to use emulate_update_regs()","version":1,"mbox":"http://patchwork.ozlabs.org/series/3263/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/814192/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/814192/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":["patchwork-incoming@ozlabs.org","linuxppc-dev@lists.ozlabs.org"],"Delivered-To":["patchwork-incoming@ozlabs.org","linuxppc-dev@lists.ozlabs.org"],"Received":["from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])\n\t(using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xtrjn39w8z9sxR\n\tfor ;\n\tFri, 15 Sep 2017 20:09:49 +1000 (AEST)","from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3])\n\tby lists.ozlabs.org (Postfix) with ESMTP id 3xtrjn298kzDrnk\n\tfor ;\n\tFri, 15 Sep 2017 20:09:49 +1000 (AEST)","from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com\n\t[148.163.156.1])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256\n\tbits)) (No client certificate requested)\n\tby lists.ozlabs.org (Postfix) with ESMTPS id 3xtrhV440fzDrYB\n\tfor ;\n\tFri, 15 Sep 2017 20:08:41 +1000 (AEST)","from pps.filterd (m0098393.ppops.net [127.0.0.1])\n\tby mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id\n\tv8FA6GkX129567\n\tfor ; Fri, 15 Sep 2017 06:08:39 -0400","from e23smtp08.au.ibm.com (e23smtp08.au.ibm.com [202.81.31.141])\n\tby mx0a-001b2d01.pphosted.com with ESMTP id 2d0a0xqrfv-1\n\t(version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT)\n\tfor ; Fri, 15 Sep 2017 06:08:39 -0400","from localhost\n\tby e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use\n\tOnly! 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Violators will be prosecuted; \n\tFri, 15 Sep 2017 20:08:34 +1000","from d23av05.au.ibm.com (d23av05.au.ibm.com [9.190.234.119])\n\tby d23relay10.au.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id\n\tv8FA8YUl23986304\n\tfor ; Fri, 15 Sep 2017 20:08:34 +1000","from d23av05.au.ibm.com (localhost [127.0.0.1])\n\tby d23av05.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id\n\tv8FA8XMO013101\n\tfor ; Fri, 15 Sep 2017 20:08:34 +1000","from naverao1-tp.ibm.com (naverao1-tp.in.ibm.com [9.124.35.115])\n\tby d23av05.au.ibm.com (8.14.4/8.14.4/NCO v10.0 AVin) with ESMTP id\n\tv8FA8U67013071; Fri, 15 Sep 2017 20:08:31 +1000"],"Authentication-Results":"ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=linux.vnet.ibm.com\n\t(client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com;\n\tenvelope-from=naveen.n.rao@linux.vnet.ibm.com; receiver=)","From":"\"Naveen N. Rao\" ","To":"Michael Ellerman ","Subject":"[PATCH] powerpc/kprobes: Update optprobes to use\n\temulate_update_regs()","Date":"Fri, 15 Sep 2017 15:38:21 +0530","X-Mailer":"git-send-email 2.14.1","X-TM-AS-MML":"disable","x-cbid":"17091510-0048-0000-0000-0000025D1B23","X-IBM-AV-DETECTION":"SAVI=unused REMOTE=unused XFE=unused","x-cbparentid":"17091510-0049-0000-0000-000048138D62","Message-Id":"<20170915100821.7254-1-naveen.n.rao@linux.vnet.ibm.com>","X-Proofpoint-Virus-Version":"vendor=fsecure engine=2.50.10432:, ,\n\tdefinitions=2017-09-15_03:, , signatures=0","X-Proofpoint-Spam-Details":"rule=outbound_notspam policy=outbound score=0\n\tspamscore=0 suspectscore=0\n\tmalwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam\n\tadjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000\n\tdefinitions=main-1709150149","X-BeenThere":"linuxppc-dev@lists.ozlabs.org","X-Mailman-Version":"2.1.24","Precedence":"list","List-Id":"Linux on PowerPC Developers Mail List\n\t","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"Anju T Sudhakar , linuxppc-dev@lists.ozlabs.org","Errors-To":"linuxppc-dev-bounces+patchwork-incoming=ozlabs.org@lists.ozlabs.org","Sender":"\"Linuxppc-dev\"\n\t"},"content":"Optprobes depended on an updated regs->nip from analyse_instr() to\nidentify the location to branch back from the optprobes trampoline.\nHowever, since commit 3cdfcbfd32b9d (\"powerpc: Change analyse_instr so\nit doesn't modify *regs\"), analyse_instr() doesn't update the registers\nanymore. Due to this, we end up branching back from the optprobes\ntrampoline to the same branch into the trampoline resulting in a loop.\n\nFix this by calling out to emulate_update_regs() before using the nip.\nAdditionally, explicitly compare the return value from analyse_instr()\nto 1, rather than just checking for !0 so as to guard against any\nfuture changes to analyse_instr() that may result in -1 being returned\nin more scenarios.\n\nFixes: 3cdfcbfd32b9d (\"powerpc: Change analyse_instr so it doesn't modify *regs\")\nSigned-off-by: Naveen N. Rao \n---\n arch/powerpc/kernel/optprobes.c | 4 +++-\n 1 file changed, 3 insertions(+), 1 deletion(-)","diff":"diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c\nindex 6f8273f5e988..91e037ab20a1 100644\n--- a/arch/powerpc/kernel/optprobes.c\n+++ b/arch/powerpc/kernel/optprobes.c\n@@ -104,8 +104,10 @@ static unsigned long can_optimize(struct kprobe *p)\n \t * and that can be emulated.\n \t */\n \tif (!is_conditional_branch(*p->ainsn.insn) &&\n-\t\t\tanalyse_instr(&op, ®s, *p->ainsn.insn))\n+\t\t\tanalyse_instr(&op, ®s, *p->ainsn.insn) == 1) {\n+\t\temulate_update_regs(®s, &op);\n \t\tnip = regs.nip;\n+\t}\n \n \treturn nip;\n }\n","prefixes":[]}