From patchwork Thu Aug 30 16:16:04 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 10582271 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6B465920 for ; Thu, 30 Aug 2018 16:28:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5962A2C10F for ; Thu, 30 Aug 2018 16:28:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4DDCB2C11C; Thu, 30 Aug 2018 16:28:35 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 376332C10F for ; Thu, 30 Aug 2018 16:28:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.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=hMQ4sp4+0jI8OhWmXdIA7lvMSLJtEUJ4THNbB+xJ8Zg=; b=LTDQtScCrq3u/7EgfpQsZsavjp rM1ZKjg8+LhNhrL46W7hoVkEET6fMBmg4cJP9kCYP+Dszg8bxcPhKdmZavyi9wVJRwrWrVtM5SfFq ecuc3qLARZJWxLxFCrXJWeMuNgstwZX+7Ei5dLKi6VZU1sJgUazUR+j9QbKInS5qSshystfuFbCFm M/Qg+kATh+lbXJw6fngHFqQmMJniQBkoO0Q4C+A46AOJcO2YHCCVshxIohzJfy0oRtf/hCKvk4gWS SrUrRx5o0Ss//TEWVTZNq7BgKz7CFICYszK3YAJufEhE5iH7sI3geGQykAUqwROUv2xixh5fJ4rtG 3mZ71REA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fvPnv-0003km-Q5; Thu, 30 Aug 2018 16:28:19 +0000 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70] helo=foss.arm.com) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fvPcD-0004iE-66 for linux-arm-kernel@lists.infradead.org; Thu, 30 Aug 2018 16:16:19 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AD37D1D70; Thu, 30 Aug 2018 09:15:58 -0700 (PDT) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 7F1ED3F557; Thu, 30 Aug 2018 09:15:58 -0700 (PDT) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id BCE0E1AE36AF; Thu, 30 Aug 2018 17:16:10 +0100 (BST) From: Will Deacon To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 4/7] arm64: entry: Allow handling of undefined instructions from EL1 Date: Thu, 30 Aug 2018 17:16:04 +0100 Message-Id: <1535645767-9901-5-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1535645767-9901-1-git-send-email-will.deacon@arm.com> References: <1535645767-9901-1-git-send-email-will.deacon@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180830_091613_481111_6B32ED24 X-CRM114-Status: GOOD ( 13.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: marc.zyngier@arm.com, catalin.marinas@arm.com, Will Deacon , christoffer.dall@arm.com, suzuki.poulose@arm.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP Rather than panic() when taking an undefined instruction exception from EL1, allow a hook to be registered in case we want to emulate the instruction, like we will for the SSBS PSTATE manipulation instructions. Signed-off-by: Will Deacon --- arch/arm64/kernel/entry.S | 2 +- arch/arm64/kernel/traps.c | 11 +++++++---- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 09dbea221a27..8556876c9109 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -589,7 +589,7 @@ el1_undef: inherit_daif pstate=x23, tmp=x2 mov x0, sp bl do_undefinstr - ASM_BUG() + kernel_exit 1 el1_dbg: /* * Debug exception handling diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 039e9ff379cc..b9da093e0341 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -310,10 +310,12 @@ static int call_undef_hook(struct pt_regs *regs) int (*fn)(struct pt_regs *regs, u32 instr) = NULL; void __user *pc = (void __user *)instruction_pointer(regs); - if (!user_mode(regs)) - return 1; - - if (compat_thumb_mode(regs)) { + if (!user_mode(regs)) { + __le32 instr_le; + if (probe_kernel_address((__force __le32 *)pc, instr_le)) + goto exit; + instr = le32_to_cpu(instr_le); + } else if (compat_thumb_mode(regs)) { /* 16-bit Thumb instruction */ __le16 instr_le; if (get_user(instr_le, (__le16 __user *)pc)) @@ -407,6 +409,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) return; force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); + BUG_ON(!user_mode(regs)); } void cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused)