From patchwork Mon Oct 27 18:40:03 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Punit Agrawal X-Patchwork-Id: 5164621 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 EF1719F318 for ; Mon, 27 Oct 2014 18:43:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 04223200E9 for ; Mon, 27 Oct 2014 18:43:25 +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 16696200E6 for ; Mon, 27 Oct 2014 18:43:24 +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 1XipEF-0001Gw-CE; Mon, 27 Oct 2014 18:41:19 +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 1XipE1-000190-T4 for linux-arm-kernel@lists.infradead.org; Mon, 27 Oct 2014 18:41:07 +0000 Received: from e105922-lin.cambridge.arm.com (e105922-lin.cambridge.arm.com [10.1.195.150]) by cam-smtp0.cambridge.arm.com (8.13.8/8.13.8) with SMTP id s9RIeg7F011654; Mon, 27 Oct 2014 18:40:42 GMT Received: by e105922-lin.cambridge.arm.com (sSMTP sendmail emulation); Mon, 27 Oct 2014 18:40:45 +0000 From: Punit Agrawal To: linux-arm-kernel@lists.infradead.org Subject: [PATCHv3 1/5] arm64: Add support for hooks to handle undefined instructions Date: Mon, 27 Oct 2014 18:40:03 +0000 Message-Id: <1414435207-30240-3-git-send-email-punit.agrawal@arm.com> X-Mailer: git-send-email 2.1.1 In-Reply-To: <1414435207-30240-1-git-send-email-punit.agrawal@arm.com> References: <1414435207-30240-1-git-send-email-punit.agrawal@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141027_114106_309879_9313CAAA X-CRM114-Status: GOOD ( 12.43 ) 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/insn.h | 2 ++ arch/arm64/include/asm/traps.h | 16 ++++++++++ arch/arm64/kernel/insn.c | 5 ++++ arch/arm64/kernel/traps.c | 68 ++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 91 insertions(+) diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index 56a9e63..2bffdc3 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -354,6 +354,8 @@ bool aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn); int aarch64_insn_patch_text_nosync(void *addr, u32 insn); int aarch64_insn_patch_text_sync(void *addrs[], u32 insns[], int cnt); int aarch64_insn_patch_text(void *addrs[], u32 insns[], int cnt); + +bool aarch32_insn_is_wide_instruction(u32 insn); #endif /* __ASSEMBLY__ */ #endif /* __ASM_INSN_H */ 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/insn.c b/arch/arm64/kernel/insn.c index e007714..9766a56 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -959,3 +959,8 @@ u32 aarch64_insn_gen_logical_shifted_reg(enum aarch64_insn_register dst, return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_6, insn, shift); } + +bool aarch32_insn_is_wide_instruction(u32 insn) +{ + return insn >= 0xe800; +} diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index de1b085..16dd73f 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -259,6 +259,71 @@ 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; @@ -268,6 +333,9 @@ 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",