From patchwork Wed Oct 1 13:37:06 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Punit Agrawal X-Patchwork-Id: 5011851 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork1.web.kernel.org (Postfix) with ESMTP id AA99F9F32B for ; Wed, 1 Oct 2014 13:40:23 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 9FB7620211 for ; Wed, 1 Oct 2014 13:40:22 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B61F3201C7 for ; Wed, 1 Oct 2014 13:40:21 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1XZK6T-0001Kh-7d; Wed, 01 Oct 2014 13:38:01 +0000 Received: from fw-tnat.cambridge.arm.com ([217.140.96.21] helo=cam-smtp0.cambridge.arm.com) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1XZK6J-00017V-Hy for linux-arm-kernel@lists.infradead.org; Wed, 01 Oct 2014 13:37:52 +0000 Received: from e102309-lin (e102309-lin.cambridge.arm.com [10.1.195.161]) by cam-smtp0.cambridge.arm.com (8.13.8/8.13.8) with SMTP id s91DbR1c006842; Wed, 1 Oct 2014 14:37:27 +0100 Received: by e102309-lin (sSMTP sendmail emulation); Wed, 01 Oct 2014 14:37:27 +0100 From: Punit Agrawal To: linux-arm-kernel@lists.infradead.org Subject: [PATCHv2 1/5] arm64: Add support for hooks to handle undefined instructions Date: Wed, 1 Oct 2014 14:37:06 +0100 Message-Id: <1412170630-18408-2-git-send-email-punit.agrawal@arm.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1412170630-18408-1-git-send-email-punit.agrawal@arm.com> References: <1412165279-8709-1-git-send-email-punit.agrawal@arm.com> <1412170630-18408-1-git-send-email-punit.agrawal@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141001_063751_942104_9C949A9A X-CRM114-Status: GOOD ( 12.47 ) X-Spam-Score: -2.9 (--) Cc: arnd@arndb.de, catalin.marinas@arm.com, Punit Agrawal , will.deacon@arm.com, ghackmann@google.com, riandrews@google.com X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-2.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add support to register hooks for undefined instructions. The handlers will be called when the undefined instruction and the processor state (as contained in pstate) match criteria used at registration. Signed-off-by: Punit Agrawal --- arch/arm64/include/asm/traps.h | 16 ++++++++++ arch/arm64/kernel/traps.c | 68 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 84 insertions(+) diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h index 10ca8ff..4faaf03 100644 --- a/arch/arm64/include/asm/traps.h +++ b/arch/arm64/include/asm/traps.h @@ -18,6 +18,22 @@ #ifndef __ASM_TRAP_H #define __ASM_TRAP_H +#include + +struct pt_regs; + +struct undef_hook { + struct list_head node; + u32 instr_mask; + u32 instr_val; + u64 pstate_mask; + u64 pstate_val; + int (*fn)(struct pt_regs *regs, u32 instr); +}; + +int register_undef_hook(struct undef_hook *hook); +void unregister_undef_hook(struct undef_hook *hook); + static inline int in_exception_text(unsigned long ptr) { extern char __exception_text_start[]; diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 02cd3f0..bcde9de 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -260,6 +260,71 @@ void arm64_notify_die(const char *str, struct pt_regs *regs, } } +static LIST_HEAD(undef_hook); +static DEFINE_RAW_SPINLOCK(undef_lock); + +int register_undef_hook(struct undef_hook *hook) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&undef_lock, flags); + list_add(&hook->node, &undef_hook); + raw_spin_unlock_irqrestore(&undef_lock, flags); + + return 0; +} + +void unregister_undef_hook(struct undef_hook *hook) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&undef_lock, flags); + list_del(&hook->node); + raw_spin_unlock_irqrestore(&undef_lock, flags); +} + +static int call_undef_hook(struct pt_regs *regs) +{ + struct undef_hook *hook; + unsigned long flags; + u32 instr; + 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)) { + /* 16-bit Thumb instruction */ + if (get_user(instr, (u16 __user *)pc)) + goto exit; + instr = le16_to_cpu(instr); + if (aarch32_insn_is_wide_instruction(instr)) { + u32 instr2; + + if (get_user(instr2, (u16 __user *)(pc + 2))) + goto exit; + instr2 = le16_to_cpu(instr2); + instr = (instr << 16) | instr2; + } + } else { + /* 32-bit ARM instruction */ + if (get_user(instr, (u32 __user *)pc)) + goto exit; + instr = le32_to_cpu(instr); + } + + raw_spin_lock_irqsave(&undef_lock, flags); + list_for_each_entry(hook, &undef_hook, node) + if ((instr & hook->instr_mask) == hook->instr_val && + (regs->pstate & hook->pstate_mask) == hook->pstate_val) + fn = hook->fn; + + raw_spin_unlock_irqrestore(&undef_lock, flags); +exit: + return fn ? fn(regs, instr) : 1; +} + asmlinkage void __exception do_undefinstr(struct pt_regs *regs) { siginfo_t info; @@ -269,6 +334,9 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) if (!aarch32_break_handler(regs)) return; + if (call_undef_hook(regs) == 0) + return; + if (show_unhandled_signals && unhandled_signal(current, SIGILL) && printk_ratelimit()) { pr_info("%s[%d]: undefined instruction: pc=%p\n",