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Sun, 2 Oct 2022 10:43:32 +0000 (GMT) Received: from li-c3569c4c-1ef8-11b2-a85c-ee139cda3133.ibm.com.com (unknown [9.43.71.20]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id C78485204E; Sun, 2 Oct 2022 10:43:28 +0000 (GMT) From: Sathvika Vasireddy To: linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 01/16] powerpc: Fix __WARN_FLAGS() for use with Objtool Date: Sun, 2 Oct 2022 16:12:25 +0530 Message-Id: <20221002104240.1316480-2-sv@linux.ibm.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20221002104240.1316480-1-sv@linux.ibm.com> References: <20221002104240.1316480-1-sv@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-GUID: hZN7-n3UnIU5SopE-_Nwy8nIJ5oVBSSJ X-Proofpoint-ORIG-GUID: rFNe2r87kg1gQrg3tSZFRYC7UCEriNLl X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.528,FMLib:17.11.122.1 definitions=2022-10-01_15,2022-09-29_03,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 mlxscore=0 clxscore=1015 mlxlogscore=911 adultscore=0 priorityscore=1501 malwarescore=0 phishscore=0 suspectscore=0 impostorscore=0 spamscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210020068 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: peterz@infradead.org, npiggin@gmail.com, linux-kernel@vger.kernel.org, aik@ozlabs.ru, mingo@redhat.com, sv@linux.ibm.com, rostedt@goodmis.org, jpoimboe@redhat.com, naveen.n.rao@linux.vnet.ibm.com, mbenes@suse.cz, chenzhongjin@huawei.com Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" Commit 1e688dd2a3d675 ("powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm goto") updated __WARN_FLAGS() to use asm goto, and added a call to 'unreachable()' after the asm goto for optimal code generation. With CONFIG_OBJTOOL enabled, 'annotate_unreachable()' statement in 'unreachable()' tries to note down the location of the subsequent instruction in a separate elf section to aid code flow analysis. However, on powerpc, this results in gcc emitting a call to a symbol of size 0. This results in objtool complaining of "unannotated intra-function call" since the target symbol is not a valid function call destination. Objtool wants this annotation for code flow analysis, which we are not yet enabling on powerpc. As such, expand the call to 'unreachable()' in __WARN_FLAGS() without annotate_unreachable(): barrier_before_unreachable(); __builtin_unreachable(); This still results in optimal code generation for __WARN_FLAGS(), while getting rid of the objtool warning. We still need barrier_before_unreachable() to work around gcc bugs 82365 and 106751: - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82365 - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106751 Reviewed-by: Christophe Leroy Signed-off-by: Sathvika Vasireddy --- arch/powerpc/include/asm/bug.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h index 61a4736355c2..ef42adb44aa3 100644 --- a/arch/powerpc/include/asm/bug.h +++ b/arch/powerpc/include/asm/bug.h @@ -99,7 +99,8 @@ __label__ __label_warn_on; \ \ WARN_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags), __label_warn_on); \ - unreachable(); \ + barrier_before_unreachable(); \ + __builtin_unreachable(); \ \ __label_warn_on: \ break; \