From patchwork Sat Jul 9 10:57:07 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tixy X-Patchwork-Id: 959812 Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by demeter1.kernel.org (8.14.4/8.14.4) with ESMTP id p69FGQJG016058 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 9 Jul 2011 15:16:49 GMT Received: from canuck.infradead.org ([2001:4978:20e::1]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QfVan-0000X8-R4; Sat, 09 Jul 2011 11:21:02 +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 1QfVOd-0007Kj-Az; Sat, 09 Jul 2011 11:08:27 +0000 Received: from smarthost02.mail.zen.net.uk ([212.23.3.141]) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QfVEO-0004Kg-Bp for linux-arm-kernel@lists.infradead.org; Sat, 09 Jul 2011 10:58:07 +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 1QfVEN-0005hJ-Oq for linux-arm-kernel@lists.infradead.org; Sat, 09 Jul 2011 10:57:51 +0000 Received: from [192.168.2.20] (helo=computer2) by plug1 with esmtp (Exim 4.72) (envelope-from ) id 1QfVEL-0003h5-SS 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-0005U3-Ng 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 20/51] ARM: kprobes: Decode 16-bit Thumb hint instructions Date: Sat, 9 Jul 2011 11:57:07 +0100 Message-Id: <1310209058-20980-21-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 0.7.6 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20110709_065753_049284_FCBDD741 X-CRM114-Status: GOOD ( 16.91 ) X-Spam-Score: 0.0 (/) X-Spam-Report: SpamAssassin version 3.3.1 on canuck.infradead.org summary: Content analysis details: (0.0 points) 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] 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 (demeter1.kernel.org [140.211.167.41]); Sat, 09 Jul 2011 15:16:50 +0000 (UTC) From: Jon Medhurst For hints which may have observable effects, like SEV (send event), we use kprobe_emulate_none which emulates the hint by executing the original instruction. For NOP we simulate the instruction using kprobe_simulate_nop, which does nothing. As probes execute with interrupts disabled this is also used for hints which may block for an indefinite time, like WFE (wait for event). Signed-off-by: Jon Medhurst --- arch/arm/kernel/kprobes.h | 3 +++ arch/arm/kernel/kprobes-common.c | 9 +++++++++ arch/arm/kernel/kprobes-thumb.c | 35 ++++++++++++++++++++++++++++++++++- 3 files changed, 46 insertions(+), 1 deletions(-) diff --git a/arch/arm/kernel/kprobes.h b/arch/arm/kernel/kprobes.h index c00681c..36e0768 100644 --- a/arch/arm/kernel/kprobes.h +++ b/arch/arm/kernel/kprobes.h @@ -95,6 +95,9 @@ static inline unsigned long it_advance(unsigned long cpsr) return cpsr; } +void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs); +void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs); + /* * Test if load/store instructions writeback the address register. * if P (bit 24) == 0 or W (bit 21) == 1 diff --git a/arch/arm/kernel/kprobes-common.c b/arch/arm/kernel/kprobes-common.c index 4074806..84c0c74 100644 --- a/arch/arm/kernel/kprobes-common.c +++ b/arch/arm/kernel/kprobes-common.c @@ -142,6 +142,15 @@ kprobe_check_cc * const kprobe_condition_checks[16] = { }; +void __kprobes kprobe_simulate_nop(struct kprobe *p, struct pt_regs *regs) +{ +} + +void __kprobes kprobe_emulate_none(struct kprobe *p, struct pt_regs *regs) +{ + p->ainsn.insn_fn(); +} + /* * Prepare an instruction slot to receive an instruction for emulating. * This is done by placing a subroutine return after the location where the diff --git a/arch/arm/kernel/kprobes-thumb.c b/arch/arm/kernel/kprobes-thumb.c index 973c3eb..7dcf6df 100644 --- a/arch/arm/kernel/kprobes-thumb.c +++ b/arch/arm/kernel/kprobes-thumb.c @@ -26,6 +26,39 @@ */ #define current_cond(cpsr) ((cpsr >> 12) & 0xf) +static const union decode_item t16_table_1011[] = { + /* Miscellaneous 16-bit instructions */ + + /* + * If-Then, and hints + * 1011 1111 xxxx xxxx + */ + + /* YIELD 1011 1111 0001 0000 */ + DECODE_OR (0xffff, 0xbf10), + /* SEV 1011 1111 0100 0000 */ + DECODE_EMULATE (0xffff, 0xbf40, kprobe_emulate_none), + /* NOP 1011 1111 0000 0000 */ + /* WFE 1011 1111 0010 0000 */ + /* WFI 1011 1111 0011 0000 */ + DECODE_SIMULATE (0xffcf, 0xbf00, kprobe_simulate_nop), + /* Unassigned hints 1011 1111 xxxx 0000 */ + DECODE_REJECT (0xff0f, 0xbf00), + + DECODE_END +}; + +const union decode_item kprobe_decode_thumb16_table[] = { + + /* + * Miscellaneous 16-bit instructions + * 1011 xxxx xxxx xxxx + */ + DECODE_TABLE (0xf000, 0xb000, t16_table_1011), + + DECODE_END +}; + static unsigned long __kprobes thumb_check_cc(unsigned long cpsr) { if (unlikely(in_it_block(cpsr))) @@ -52,7 +85,7 @@ thumb16_kprobe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi) { asi->insn_singlestep = thumb16_singlestep; asi->insn_check_cc = thumb_check_cc; - return INSN_REJECTED; + return kprobe_decode_insn(insn, asi, kprobe_decode_thumb16_table, true); } enum kprobe_insn __kprobes