From patchwork Thu Dec 1 07:56:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christophe Leroy X-Patchwork-Id: 13061028 X-Patchwork-Delegate: bpf@iogearbox.net 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 77789C4708C for ; Thu, 1 Dec 2022 07:57:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229680AbiLAH5H (ORCPT ); Thu, 1 Dec 2022 02:57:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbiLAH5G (ORCPT ); Thu, 1 Dec 2022 02:57:06 -0500 Received: from pegase2.c-s.fr (pegase2.c-s.fr [93.17.235.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 633F551316; Wed, 30 Nov 2022 23:57:05 -0800 (PST) Received: from localhost (mailhub3.si.c-s.fr [172.26.127.67]) by localhost (Postfix) with ESMTP id 4NN7hF2Bj9z9sb3; Thu, 1 Dec 2022 08:57:01 +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 U755w7Mnx6tw; Thu, 1 Dec 2022 08:57:01 +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 4NN7hD3KzMz9sXw; Thu, 1 Dec 2022 08:57:00 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 5D0688B78D; Thu, 1 Dec 2022 08:57:00 +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 HysRZHYumzPh; Thu, 1 Dec 2022 08:57:00 +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 D153E8B787; Thu, 1 Dec 2022 08:56:59 +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 2B17uuGB130806 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Thu, 1 Dec 2022 08:56:56 +0100 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 2B17uuau130794; Thu, 1 Dec 2022 08:56:56 +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 v1 02/10] powerpc: Remove __kernel_text_address() in show_instructions() Date: Thu, 1 Dec 2022 08:56:27 +0100 Message-Id: <96a35025667d6e44f5253f82f61bb49b0a6ecf2a.1669881248.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.38.1 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1669881390; l=1412; s=20211009; h=from:subject:message-id; bh=/zpH2ZZvEoJhCvxUe4ujuN1Lgf9RLeBH5yxOMRR6WTo=; b=VO+bDKToRC6Z5qShLIgfWwHi4YRQyWdYTYB6ld+4YoQvb5mLByEIdDa3Pk7kXIovhVtsg6pGixkz x7bgqbDbBxts/Evn0oZmXOnVq3gJ9+QZTXiuGSLkD57Qv+Byc1IZ 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 e3e1feaa536a..c4e9f090ad22 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1373,8 +1373,7 @@ 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)