From patchwork Mon Sep 14 08:36:56 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Amit Daniel Kachhap X-Patchwork-Id: 11773279 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 80AFA618 for ; Mon, 14 Sep 2020 08:39:03 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 3F50B21548 for ; Mon, 14 Sep 2020 08:39:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="08X9z6YC" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F50B21548 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:References:In-Reply-To:Message-Id:Date:Subject:To: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Dmwv1Ty6rCjUtUYsdxcJTRtR9IunkDhYjpOCEI1fWqM=; b=08X9z6YC7HDFc9dbLP6UCVSmqL ZhgwkD237RJItcBGk179joAKsp2l4GXSflKOwa4FDgGX+vtyNZAmcKf6FgE4j+5Zeys/iEN4oKEyT Fu8mxmJDQ8b2zFTKpxtDFZAMtEOBpcPs/2ebpqi6w6sxCw36zR9v8jckip8Nn9Ss33ONwwcS7rgqM 055zSEbKG0HTlbzenA11TW1IYOSjAI1vWZU1G/lLqEdxc6Z62kct5Tt8P9+giUIM9UMPU6aPXml2s 1D5SwEC5i2i+e5Ii7zTwaAkELB1hh2L8X87OvaRg6h4zC+YrXDpXjSwDLhvXUnCmiejeC/2B5NqZ8 jvhGsevA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kHjzi-0004gB-Lk; Mon, 14 Sep 2020 08:37:50 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kHjzP-0004ZU-EE for linux-arm-kernel@lists.infradead.org; Mon, 14 Sep 2020 08:37:32 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 891DB1045; Mon, 14 Sep 2020 01:37:30 -0700 (PDT) Received: from a077416.blr.arm.com (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5ACA53F718; Mon, 14 Sep 2020 01:37:27 -0700 (PDT) From: Amit Daniel Kachhap To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v8 6/6] arm64: kprobe: clarify the comment of steppable hint instructions Date: Mon, 14 Sep 2020 14:06:56 +0530 Message-Id: <20200914083656.21428-7-amit.kachhap@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200914083656.21428-1-amit.kachhap@arm.com> References: <20200914083656.21428-1-amit.kachhap@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200914_043731_584792_E8BFDFA3 X-CRM114-Status: GOOD ( 13.05 ) X-Spam-Score: -2.3 (--) X-Spam-Report: SpamAssassin version 3.4.4 on merlin.infradead.org summary: Content analysis details: (-2.3 points) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at https://www.dnswl.org/, medium trust [217.140.110.172 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Catalin Marinas , Mark Brown , James Morse , Amit Daniel Kachhap , Vincenzo Frascino , Will Deacon , Dave Martin MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org The existing comment about steppable hint instruction is not complete and only describes NOP instructions as steppable. As the function aarch64_insn_is_steppable_hint allows all white-listed instruction to be probed so the comment is updated to reflect this. Signed-off-by: Amit Daniel Kachhap Reviewed-by: Dave Martin --- arch/arm64/kernel/probes/decode-insn.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c index c541fb48886e..104101f633b1 100644 --- a/arch/arm64/kernel/probes/decode-insn.c +++ b/arch/arm64/kernel/probes/decode-insn.c @@ -43,8 +43,10 @@ static bool __kprobes aarch64_insn_is_steppable(u32 insn) != AARCH64_INSN_SPCLREG_DAIF; /* - * The HINT instruction is is problematic when single-stepping, - * except for the NOP case. + * The HINT instruction is steppable only if it is in whitelist + * and the rest of other such instructions are blocked for + * single stepping as they may cause exception or other + * unintended behaviour. */ if (aarch64_insn_is_hint(insn)) return aarch64_insn_is_steppable_hint(insn);