From patchwork Fri Oct 14 01:59:56 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhen Lei X-Patchwork-Id: 13006586 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2FA8EC4332F for ; Fri, 14 Oct 2022 02:02:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:CC:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WeQS4RKaVy963uJtBMCmHRxaP7FjtXl8kNyBoALt7Ys=; b=nEQYZ57WmJz7qn 7x8gBdvm0J0nzVnZketqz5t52E9RAf9Lm3lZaGHJ3oQzxNe1Euia4r2w+bPNQix4cCtBl8BGiN3z5 OgHYwYQkXEM+yHnOpovA/S8xhLFlfiH9hUWp0XmlEA9pZCLHlObtnWrHsfrEDulwKCf/00TiGSgDM CdQajeZs+StLlwICoMZngQyhY5d4DiEi+Jd5iudh9fKpJYbdOI92MJcj+VcmZboDbye67xSkaPh3Z UCSYkUgI0H9gI7AZU1mkfqf4PdUWzLwwnwqzqj51A26GEVLlaRp7JC5C/lO+DzLxv+AXmMIWti3in f5fsqnxiBpIsHrz56C9g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ojA0p-00DLTp-SE; Fri, 14 Oct 2022 02:01:23 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ojA0P-00DLJW-S8 for linux-arm-kernel@lists.infradead.org; Fri, 14 Oct 2022 02:01:01 +0000 Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.54]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MpV3G2JHHzHtxF; Fri, 14 Oct 2022 10:00:42 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 14 Oct 2022 10:00:44 +0800 Received: from thunder-town.china.huawei.com (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.31; Fri, 14 Oct 2022 10:00:44 +0800 From: Zhen Lei To: Russell King , Ard Biesheuvel , , CC: Zhen Lei Subject: [PATCH v3 3/3] ARM: Make the dumped instructions are consistent with the disassembled ones Date: Fri, 14 Oct 2022 09:59:56 +0800 Message-ID: <20221014015956.2006-4-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.37.3.windows.1 In-Reply-To: <20221014015956.2006-1-thunder.leizhen@huawei.com> References: <20221014015956.2006-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221013_190058_093568_A603A7C8 X-CRM114-Status: GOOD ( 11.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org In ARM, the mapping of instruction memory is always little-endian, except some BE-32 supported ARM architectures. Such as ARMv7-R, its instruction endianness may be BE-32. Of course, its data endianness will also be BE-32 mode. Due to two negatives make a positive, the instruction stored in the register after reading is in little-endian format. But for the case of BE-8, the instruction endianness is LE, the instruction stored in the register after reading is in big-endian format, which is inconsistent with the disassembled one. For example: The content of disassembly: c0429ee8: e3500000 cmp r0, #0 c0429eec: 159f2044 ldrne r2, [pc, #68] c0429ef0: 108f2002 addne r2, pc, r2 c0429ef4: 1882000a stmne r2, {r1, r3} c0429ef8: e7f000f0 udf #0 The output of undefined instruction exception: Internal error: Oops - undefined instruction: 0 [#1] SMP ARM ... ... Code: 000050e3 44209f15 02208f10 0a008218 (f000f0e7) This inconveniences the checking of instructions. What's worse is that, for somebody who don't know about this, might think the instructions are all broken. So, when CONFIG_CPU_ENDIAN_BE8=y, let's convert the instructions to little-endian format before they are printed. The conversion result is as follows: Code: e3500000 159f2044 108f2002 1882000a (e7f000f0) Signed-off-by: Zhen Lei --- arch/arm/kernel/traps.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c index 182469a5b28a394..8a7f216156675a1 100644 --- a/arch/arm/kernel/traps.c +++ b/arch/arm/kernel/traps.c @@ -186,12 +186,14 @@ static void dump_instr(const char *lvl, struct pt_regs *regs) else bad = get_kernel_nofault(tmp, &((u16 *)addr)[i]); - val = tmp; + val = __mem_to_opcode_thumb16(tmp); } else { if (user_mode(regs)) bad = get_user(val, &((u32 __user *)addr)[i]); else bad = get_kernel_nofault(val, &((u32 *)addr)[i]); + + val = __mem_to_opcode_arm(val); } if (!bad)