From patchwork Wed Jan 7 11:50:36 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jon Medhurst (Tixy)" X-Patchwork-Id: 5584341 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 [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 150919F443 for ; Wed, 7 Jan 2015 11:59:29 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C62B320263 for ; Wed, 7 Jan 2015 11:59:27 +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 CD7FB201D3 for ; Wed, 7 Jan 2015 11:59:26 +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 1Y8pDq-0007e1-C7; Wed, 07 Jan 2015 11:56:22 +0000 Received: from smarthost01a.mail.zen.net.uk ([212.23.1.1]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Y8p8m-0003mz-H3 for linux-arm-kernel@lists.infradead.org; Wed, 07 Jan 2015 11:51:10 +0000 Received: from [82.69.122.217] (helo=linaro1) by smarthost01a.mail.zen.net.uk with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.80) (envelope-from ) id 1Y8p8G-000GZS-Qa; Wed, 07 Jan 2015 11:50:36 +0000 Message-ID: <1420631436.4044.26.camel@linaro.org> Subject: Re: [PATCH v19 02/11] ARM: kprobes: remove unused ARM decoder actions. From: "Jon Medhurst (Tixy)" To: Wang Nan , David Long Date: Wed, 07 Jan 2015 11:50:36 +0000 In-Reply-To: <1420457354-77099-1-git-send-email-wangnan0@huawei.com> References: <1420457284-76923-1-git-send-email-wangnan0@huawei.com> <1420457354-77099-1-git-send-email-wangnan0@huawei.com> X-Mailer: Evolution 3.12.9-1 Mime-Version: 1.0 X-Originating-smarthost01a-IP: [82.69.122.217] X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150107_035108_819403_21873B93 X-CRM114-Status: GOOD ( 12.37 ) X-Spam-Score: 0.3 (/) Cc: masami.hiramatsu.pt@hitachi.com, lizefan@huawei.com, linux@arm.linux.org.uk, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, T_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 On Mon, 2015-01-05 at 19:29 +0800, Wang Nan wrote: > There are 3 actions which is never used: > > PROBES_MOV_HALFWORD, > PROBES_SEV, > PROBES_WFE, > > This patch removes them. > > Signed-off-by: Wang Nan I think that PROBES_MOV_HALFWORD should be used, for MOVW and MOVT. Currently those instructions use PROBES_DATA_PROCESSING_IMM which, whilst it will work it ends up using a less efficient emulation routine than necessary. The other unused actions, PROBES_SEV and PROBES_WFE, could possibly be removed as redundant, but there are are Thumb equivalents for those which are used, so for symmetry I think we should use them. That will let us remove PROBES_EMULATE_NONE and PROBES_SIMULATE_NOP. So how about the following patch instead... ---------------------------------------------------------------------------- From: Jon Medhurst Date: Wed, 7 Jan 2015 11:42:30 +0000 Subject: [PATCH] ARM: probes: Use correct action types for MOVW, SEV and WFI This doesn't correct any bugs when probing these instructions but makes MOVW slightly faster and makes everything more symmetric with the Thumb instruction cases. We can also remove the now redundant PROBES_EMULATE_NONE and PROBES_SIMULATE_NOP actions. Signed-off-by: Jon Medhurst --- arch/arm/probes/decode-arm.c | 6 +++--- arch/arm/probes/decode-arm.h | 2 -- arch/arm/probes/kprobes/actions-arm.c | 2 -- arch/arm/probes/uprobes/actions-arm.c | 2 -- 4 files changed, 3 insertions(+), 9 deletions(-) diff --git a/arch/arm/probes/decode-arm.c b/arch/arm/probes/decode-arm.c index f46d8fc..f72c33a 100644 --- a/arch/arm/probes/decode-arm.c +++ b/arch/arm/probes/decode-arm.c @@ -370,17 +370,17 @@ static const union decode_item arm_cccc_001x_table[] = { /* MOVW cccc 0011 0000 xxxx xxxx xxxx xxxx xxxx */ /* MOVT cccc 0011 0100 xxxx xxxx xxxx xxxx xxxx */ - DECODE_EMULATEX (0x0fb00000, 0x03000000, PROBES_DATA_PROCESSING_IMM, + DECODE_EMULATEX (0x0fb00000, 0x03000000, PROBES_MOV_HALFWORD, REGS(0, NOPC, 0, 0, 0)), /* YIELD cccc 0011 0010 0000 xxxx xxxx 0000 0001 */ DECODE_OR (0x0fff00ff, 0x03200001), /* SEV cccc 0011 0010 0000 xxxx xxxx 0000 0100 */ - DECODE_EMULATE (0x0fff00ff, 0x03200004, PROBES_EMULATE_NONE), + DECODE_EMULATE (0x0fff00ff, 0x03200004, PROBES_SEV), /* NOP cccc 0011 0010 0000 xxxx xxxx 0000 0000 */ /* WFE cccc 0011 0010 0000 xxxx xxxx 0000 0010 */ /* WFI cccc 0011 0010 0000 xxxx xxxx 0000 0011 */ - DECODE_SIMULATE (0x0fff00fc, 0x03200000, PROBES_SIMULATE_NOP), + DECODE_SIMULATE (0x0fff00fc, 0x03200000, PROBES_WFE), /* DBG cccc 0011 0010 0000 xxxx xxxx ffff xxxx */ /* unallocated hints cccc 0011 0010 0000 xxxx xxxx xxxx xxxx */ /* MSR (immediate) cccc 0011 0x10 xxxx xxxx xxxx xxxx xxxx */ diff --git a/arch/arm/probes/decode-arm.h b/arch/arm/probes/decode-arm.h index a7b0398..b3b80f6 100644 --- a/arch/arm/probes/decode-arm.h +++ b/arch/arm/probes/decode-arm.h @@ -18,8 +18,6 @@ #include "decode.h" enum probes_arm_action { - PROBES_EMULATE_NONE, - PROBES_SIMULATE_NOP, PROBES_PRELOAD_IMM, PROBES_PRELOAD_REG, PROBES_BRANCH_IMM, diff --git a/arch/arm/probes/kprobes/actions-arm.c b/arch/arm/probes/kprobes/actions-arm.c index 1e67839..06988ef 100644 --- a/arch/arm/probes/kprobes/actions-arm.c +++ b/arch/arm/probes/kprobes/actions-arm.c @@ -303,8 +303,6 @@ emulate_rdlo12rdhi16rn0rm8_rwflags_nopc(probes_opcode_t insn, } const union decode_action kprobes_arm_actions[NUM_PROBES_ARM_ACTIONS] = { - [PROBES_EMULATE_NONE] = {.handler = probes_emulate_none}, - [PROBES_SIMULATE_NOP] = {.handler = probes_simulate_nop}, [PROBES_PRELOAD_IMM] = {.handler = probes_simulate_nop}, [PROBES_PRELOAD_REG] = {.handler = probes_simulate_nop}, [PROBES_BRANCH_IMM] = {.handler = simulate_blx1}, diff --git a/arch/arm/probes/uprobes/actions-arm.c b/arch/arm/probes/uprobes/actions-arm.c index 1dd4916..76eb449 100644 --- a/arch/arm/probes/uprobes/actions-arm.c +++ b/arch/arm/probes/uprobes/actions-arm.c @@ -195,8 +195,6 @@ uprobe_decode_ldmstm(probes_opcode_t insn, } const union decode_action uprobes_probes_actions[] = { - [PROBES_EMULATE_NONE] = {.handler = probes_simulate_nop}, - [PROBES_SIMULATE_NOP] = {.handler = probes_simulate_nop}, [PROBES_PRELOAD_IMM] = {.handler = probes_simulate_nop}, [PROBES_PRELOAD_REG] = {.handler = probes_simulate_nop}, [PROBES_BRANCH_IMM] = {.handler = simulate_blx1},