From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C20DAC55193 for ; Thu, 23 Apr 2020 15:35:04 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2F50E2076C for ; Thu, 23 Apr 2020 15:35:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F50E2076C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.vnet.ibm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 497Lw36s05zDqdG for ; Fri, 24 Apr 2020 01:34:59 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=linux.vnet.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=naveen.n.rao@linux.vnet.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.vnet.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 497LMS2cWwzDr1F for ; Fri, 24 Apr 2020 01:10:12 +1000 (AEST) Received: from pps.filterd (m0098410.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 03NF3hJJ065605; Thu, 23 Apr 2020 11:09:40 -0400 Received: from ppma03ams.nl.ibm.com (62.31.33a9.ip4.static.sl-reverse.com [169.51.49.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 30k09wqrxh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 23 Apr 2020 11:09:40 -0400 Received: from pps.filterd (ppma03ams.nl.ibm.com [127.0.0.1]) by ppma03ams.nl.ibm.com (8.16.0.27/8.16.0.27) with SMTP id 03NF6Fdu017128; Thu, 23 Apr 2020 15:09:37 GMT Received: from b06avi18878370.portsmouth.uk.ibm.com (b06avi18878370.portsmouth.uk.ibm.com [9.149.26.194]) by ppma03ams.nl.ibm.com with ESMTP id 30fs6582n2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 23 Apr 2020 15:09:37 +0000 Received: from d06av26.portsmouth.uk.ibm.com (d06av26.portsmouth.uk.ibm.com [9.149.105.62]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 03NF9ZO750921924 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 23 Apr 2020 15:09:35 GMT Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 32565AE051; Thu, 23 Apr 2020 15:09:35 +0000 (GMT) Received: from d06av26.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C3230AE055; Thu, 23 Apr 2020 15:09:33 +0000 (GMT) Received: from naverao1-tp.ibmuc.com (unknown [9.85.73.158]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 23 Apr 2020 15:09:33 +0000 (GMT) From: "Naveen N. Rao" To: Subject: [PATCH 2/3] powerpc/ftrace: Simplify error checking when patching instructions Date: Thu, 23 Apr 2020 20:39:03 +0530 Message-Id: <872c5c3d9cf6db8e52b2abcdd16d7ab61fce8070.1587654213.git.naveen.n.rao@linux.vnet.ibm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.676 definitions=2020-04-23_10:2020-04-23, 2020-04-23 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 suspectscore=1 phishscore=0 clxscore=1015 adultscore=0 mlxlogscore=999 bulkscore=0 impostorscore=0 spamscore=0 mlxscore=0 priorityscore=1501 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004230118 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: Steven Rostedt Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Introduce a macro PATCH_INSN() to simplify instruction patching, and to make the error messages more uniform and useful: - print an error message that includes the original return value - print the function name and line numbers, so that the offending location is clear - always return -EPERM, which ftrace_bug() expects for proper error handling Also eliminate use of patch_branch() since most such uses already call create_branch() for error checking before patching. Instead, use the return value from create_branch() with PATCH_INSN(). Signed-off-by: Naveen N. Rao --- arch/powerpc/kernel/trace/ftrace.c | 69 ++++++++++++++---------------- 1 file changed, 33 insertions(+), 36 deletions(-) diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c index 7ea0ca044b65..5cf84c0c64cb 100644 --- a/arch/powerpc/kernel/trace/ftrace.c +++ b/arch/powerpc/kernel/trace/ftrace.c @@ -31,6 +31,17 @@ #ifdef CONFIG_DYNAMIC_FTRACE +#define PATCH_INSN(addr, instr) \ +do { \ + int rc = patch_instruction((unsigned int *)(addr), instr); \ + if (rc) { \ + pr_err("%s:%d Error patching instruction at 0x%pK (%pS): %d\n", \ + __func__, __LINE__, \ + (void *)(addr), (void *)(addr), rc); \ + return -EPERM; \ + } \ +} while (0) + /* * We generally only have a single long_branch tramp and at most 2 or 3 plt * tramps generated. But, we don't use the plt tramps currently. We also allot @@ -78,8 +89,7 @@ ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new) } /* replace the text with the new text */ - if (patch_instruction((unsigned int *)ip, new)) - return -EPERM; + PATCH_INSN(ip, new); return 0; } @@ -204,10 +214,7 @@ __ftrace_make_nop(struct module *mod, } #endif /* CONFIG_MPROFILE_KERNEL */ - if (patch_instruction((unsigned int *)ip, pop)) { - pr_err("Patching NOP failed.\n"); - return -EPERM; - } + PATCH_INSN(ip, pop); return 0; } @@ -276,8 +283,7 @@ __ftrace_make_nop(struct module *mod, op = PPC_INST_NOP; - if (patch_instruction((unsigned int *)ip, op)) - return -EPERM; + PATCH_INSN(ip, op); return 0; } @@ -322,7 +328,7 @@ static int add_ftrace_tramp(unsigned long tramp) */ static int setup_mcount_compiler_tramp(unsigned long tramp) { - int i, op; + unsigned int i, op; unsigned long ptr; static unsigned long ftrace_plt_tramps[NUM_FTRACE_TRAMPS]; @@ -366,16 +372,14 @@ static int setup_mcount_compiler_tramp(unsigned long tramp) #else ptr = ppc_global_function_entry((void *)ftrace_caller); #endif - if (!create_branch((void *)tramp, ptr, 0)) { + op = create_branch((void *)tramp, ptr, 0); + if (!op) { pr_debug("%ps is not reachable from existing mcount tramp\n", (void *)ptr); return -1; } - if (patch_branch((unsigned int *)tramp, ptr, 0)) { - pr_debug("REL24 out of range!\n"); - return -1; - } + PATCH_INSN(tramp, op); if (add_ftrace_tramp(tramp)) { pr_debug("No tramp locations left\n"); @@ -416,10 +420,7 @@ static int __ftrace_make_nop_kernel(struct dyn_ftrace *rec, unsigned long addr) } } - if (patch_instruction((unsigned int *)ip, PPC_INST_NOP)) { - pr_err("Patching NOP failed.\n"); - return -EPERM; - } + PATCH_INSN(ip, PPC_INST_NOP); return 0; } @@ -557,15 +558,13 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) } /* Ensure branch is within 24 bits */ - if (!create_branch(ip, tramp, BRANCH_SET_LINK)) { + op[0] = create_branch(ip, tramp, BRANCH_SET_LINK); + if (!op[0]) { pr_err("Branch out of range\n"); return -EINVAL; } - if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } + PATCH_INSN(ip, op[0]); return 0; } @@ -603,8 +602,7 @@ __ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) pr_devel("write to %lx\n", rec->ip); - if (patch_instruction((unsigned int *)ip, op)) - return -EPERM; + PATCH_INSN(ip, op); return 0; } @@ -650,11 +648,14 @@ static int __ftrace_make_call_kernel(struct dyn_ftrace *rec, unsigned long addr) return -EINVAL; } - if (patch_branch(ip, tramp, BRANCH_SET_LINK)) { - pr_err("Error patching branch to ftrace tramp!\n"); + op = create_branch(ip, tramp, BRANCH_SET_LINK); + if (!op) { + pr_err("Branch out of range\n"); return -EINVAL; } + PATCH_INSN(ip, op); + return 0; } @@ -748,10 +749,8 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, /* The new target may be within range */ if (test_24bit_addr(ip, addr)) { /* within range */ - if (patch_branch((unsigned int *)ip, addr, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } + op = create_branch((unsigned int *)ip, addr, BRANCH_SET_LINK); + PATCH_INSN(ip, op); return 0; } @@ -776,15 +775,13 @@ __ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, } /* Ensure branch is within 24 bits */ - if (!create_branch((unsigned int *)ip, tramp, BRANCH_SET_LINK)) { + op = create_branch((unsigned int *)ip, tramp, BRANCH_SET_LINK); + if (!op) { pr_err("Branch out of range\n"); return -EINVAL; } - if (patch_branch((unsigned int *)ip, tramp, BRANCH_SET_LINK)) { - pr_err("REL24 out of range!\n"); - return -EINVAL; - } + PATCH_INSN(ip, op); return 0; } -- 2.25.1