From patchwork Wed Feb 1 10:04:23 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 13124009 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D868BC636D3 for ; Wed, 1 Feb 2023 10:05:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231515AbjBAKFA (ORCPT ); Wed, 1 Feb 2023 05:05:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230231AbjBAKE4 (ORCPT ); Wed, 1 Feb 2023 05:04:56 -0500 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC1C4521D9; Wed, 1 Feb 2023 02:04:54 -0800 (PST) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4P6Hb80XZtz9sgV; Wed, 1 Feb 2023 11:04:52 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase2.c-s.fr ([172.26.127.65]) by localhost (pegase2.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id pfKvoLcWp1ya; Wed, 1 Feb 2023 11:04:51 +0100 (CET) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase2.c-s.fr (Postfix) with ESMTP id 4P6Hb75Jwbz9sgS; Wed, 1 Feb 2023 11:04:51 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 9D96F8B778; Wed, 1 Feb 2023 11:04:51 +0100 (CET) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id 9AWk4czKjhj2; Wed, 1 Feb 2023 11:04:51 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (unknown [172.25.230.108]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 708108B774; Wed, 1 Feb 2023 11:04:51 +0100 (CET) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 311A4koj3908564 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Wed, 1 Feb 2023 11:04:46 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 311A4joX3908560; Wed, 1 Feb 2023 11:04:45 +0100 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Michael Ellerman , Nicholas Piggin , "Naveen N. Rao" Cc: Christophe Leroy , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, bpf@vger.kernel.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa Subject: [PATCH v2 1/9] powerpc: Remove __kernel_text_address() in show_instructions() Date: Wed, 1 Feb 2023 11:04:23 +0100 Message-Id: <4fd69ef7945518c3e27f96b95046a5c1468d35bf.1675245773.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.39.1 MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1675245868; l=1412; s=20211009; h=from:subject:message-id; bh=ufuT7Fs0n0E5kHjHlxoLhXc06DUToCzE0Lr3IX5svRY=; b=YUZV2g3JyPlCN28EMk40ZLxbOsMooWZUeumDCP9XNjrtG6a++bpU1H+cxA7VVz9ho6hTLu/2+5kQ EAze5cM2A/h9xHMVCG9O7vVaFPnHR0frBxfOFm5tT0gnQCyKN/9t X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org That test was introducted in 2006 by commit 00ae36de49cc ("[POWERPC] Better check in show_instructions"). At that time, there was no BPF progs. As seen in message of commit 89d21e259a94 ("powerpc/bpf/32: Fix Oops on tail call tests"), when a page fault occurs in test_bpf.ko for instance, the code is dumped as XXXXXXXXs. Allthough __kernel_text_address() checks is_bpf_text_address(), it seems it is not enough. Today, show_instructions() uses get_kernel_nofault() to read the code, so there is no real need for additional verifications. ARM64 and x86 don't do any additional check before dumping instructions. Do the same and remove __kernel_text_address() in show_instructions(). Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/process.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index c22cc234672f..effe9697905d 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1405,8 +1405,7 @@ static void show_instructions(struct pt_regs *regs) for (i = 0; i < NR_INSN_TO_PRINT; i++) { int instr; - if (!__kernel_text_address(pc) || - get_kernel_nofault(instr, (const void *)pc)) { + if (get_kernel_nofault(instr, (const void *)pc)) { pr_cont("XXXXXXXX "); } else { if (nip == pc)