From patchwork Sat Jul 9 10:57:11 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tixy X-Patchwork-Id: 959062 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p69B3Z5o022129 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 9 Jul 2011 11:03:58 GMT Received: from canuck.infradead.org ([2001:4978:20e::1]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QfVIY-0003bb-2t; Sat, 09 Jul 2011 11:02:10 +0000 Received: from localhost ([127.0.0.1] helo=canuck.infradead.org) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QfVIX-0005Vw-E1; Sat, 09 Jul 2011 11:02:09 +0000 Received: from casper.infradead.org ([2001:770:15f::2]) by canuck.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QfVEW-0004PL-Oy for linux-arm-kernel@canuck.infradead.org; Sat, 09 Jul 2011 10:58:00 +0000 Received: from smarthost02.mail.zen.net.uk ([212.23.3.141]) by casper.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QfVEQ-0006Cn-Fm for linux-arm-kernel@lists.infradead.org; Sat, 09 Jul 2011 10:57:59 +0000 Received: from [82.69.122.217] (helo=plug1) by smarthost02.mail.zen.net.uk with esmtpsa (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.63) (envelope-from ) id 1QfVEO-0005hb-BC for linux-arm-kernel@lists.infradead.org; Sat, 09 Jul 2011 10:57:52 +0000 Received: from [192.168.2.20] (helo=computer2) by plug1 with esmtp (Exim 4.72) (envelope-from ) id 1QfVEM-0003hC-4J for linux-arm-kernel@lists.infradead.org; Sat, 09 Jul 2011 11:57:50 +0100 Received: from tixy by computer2 with local (Exim 4.72) (envelope-from ) id 1QfVEL-0005UF-US for linux-arm-kernel@lists.infradead.org; Sat, 09 Jul 2011 11:57:49 +0100 From: Tixy To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 24/51] ARM: kprobes: Decode 16-bit Thumb BX and BLX instructions Date: Sat, 9 Jul 2011 11:57:11 +0100 Message-Id: <1310209058-20980-25-git-send-email-tixy@yxit.co.uk> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1310209058-20980-1-git-send-email-tixy@yxit.co.uk> References: <1310209058-20980-1-git-send-email-tixy@yxit.co.uk> X-Originating-Smarthost02-IP: [82.69.122.217] X-CRM114-Version: 20090807-BlameThorstenAndJenny ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20110709_115754_730648_51B6C668 X-CRM114-Status: GOOD ( 16.34 ) X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.3.2-r929478 on casper.infradead.org summary: Content analysis details: (-1.9 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [212.23.3.141 listed in list.dnswl.org] -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Sat, 09 Jul 2011 11:03:58 +0000 (UTC) From: Jon Medhurst Signed-off-by: Jon Medhurst --- arch/arm/kernel/kprobes-thumb.c | 37 +++++++++++++++++++++++++++++++++++++ 1 files changed, 37 insertions(+), 0 deletions(-) diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c index e1cef82..b457da0 100644 --- a/arch/arm/kernel/kprobes-thumb.c +++ b/arch/arm/kernel/kprobes-thumb.c @@ -26,6 +26,31 @@ */ #define current_cond(cpsr) ((cpsr >> 12) & 0xf) +/* + * Return the PC value for a probe in thumb code. + * This is the address of the probed instruction plus 4. + * We subtract one because the address will have bit zero set to indicate + * a pointer to thumb code. + */ +static inline unsigned long __kprobes thumb_probe_pc(struct kprobe *p) +{ + return (unsigned long)p->addr - 1 + 4; +} + +static void __kprobes +t16_simulate_bxblx(struct kprobe *p, struct pt_regs *regs) +{ + kprobe_opcode_t insn = p->opcode; + unsigned long pc = thumb_probe_pc(p); + int rm = (insn >> 3) & 0xf; + unsigned long rmv = (rm == 15) ? pc : regs->uregs[rm]; + + if (insn & (1 << 7)) /* BLX ? */ + regs->ARM_lr = (unsigned long)p->addr + 2; + + bx_write_pc(rmv, regs); +} + static unsigned long __kprobes t16_emulate_loregs(struct kprobe *p, struct pt_regs *regs) { @@ -132,6 +157,18 @@ const union decode_item kprobe_decode_thumb16_table[] = { DECODE_EMULATE (0xfc00, 0x4000, t16_emulate_loregs_noitrwflags), /* + * Special data instructions and branch and exchange + * 0100 01xx xxxx xxxx + */ + + /* BLX pc 0100 0111 1111 1xxx */ + DECODE_REJECT (0xfff8, 0x47f8), + + /* BX (register) 0100 0111 0xxx xxxx */ + /* BLX (register) 0100 0111 1xxx xxxx */ + DECODE_SIMULATE (0xff00, 0x4700, t16_simulate_bxblx), + + /* * Miscellaneous 16-bit instructions * 1011 xxxx xxxx xxxx */