From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9AAAEECE58D for ; Fri, 11 Oct 2019 20:16:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69AEF218AC for ; Fri, 11 Oct 2019 20:16:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="Jy+yz6cs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729325AbfJKUQK (ORCPT ); Fri, 11 Oct 2019 16:16:10 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:33293 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729087AbfJKUQK (ORCPT ); Fri, 11 Oct 2019 16:16:10 -0400 Received: by mail-pf1-f194.google.com with SMTP id q10so6732384pfl.0 for ; Fri, 11 Oct 2019 13:16:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=PR46YI2RMcoiv8IfiEatQgc8ZaD0QWUbng9pxbLKT2g=; b=Jy+yz6cspKP36E2xWln+kXX+hRDBKhLWAYgzxCz734kBlvsoc9VIusa25mAMklPTjM CGRVYpf1ioSv9f7+fT+hvhHdxgmGqXO2cPhAPSGNWvTKcevKLlnFxEh8pHT5m/v28oXj /n8h7fnbtr0/Y0NfSf5uIU8H6FWYq2NKn2mK9pg+fZ0e6fxC4taVdvdiMQrJb9NukCaL tEYoPdH7J8Pxtx9jcKLwf5U1f53BePopdUr8SwpV/rGTlKek88ROJ562DmbUKQ+E0qN2 7X4+XA73UIIcxTJDul1+A5OjLyPlQsmc0g5IEuSz5U/v67gMJK4fVmS8DQa2p9JVKGot 7F1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=PR46YI2RMcoiv8IfiEatQgc8ZaD0QWUbng9pxbLKT2g=; b=gR0OL3D2GkOGnmTn3CKvalb6k7PvHUmldQrYDbQ5FPLzjPQKDcTAY7tVpeFexDLDxL zD/749hQrHjAkspH2EiZds+me4xfoNK7T+D3L43wdkevyrODCYtBFYBAHDid7nz6m9h/ 8mEUCH5mPOK4RZVP6MuSOhbLWdCEHO4oybAZ0/yd4SnehHWYQkUQXwcC0kRG4tAv7DSO AAaAmyfTSVyBg/GTBWNb8oQQ+JWFgUqgg9lKCnipf2WP3+71yVRn+ORTFKNIZxfwBi6y lp40QVlSZlISgfVKcw3rlbrmC6rL1fnep7LK164GOKReyI7RjzqFxhG3WR7MtUGRRV/x mjGw== X-Gm-Message-State: APjAAAU9uL55U+4l5o5ql1DPUcWaZleDiiD0BQs65ONovJriML6tO+7r 1pCTmikfvJjHSXW5TJ+pw0VriA== X-Google-Smtp-Source: APXvYqwEyiiUYWnxVo/iZMPv/NTiwhPMmTvQy5U8FMYGFAVmjoSfpr6Hd/ZFZ7xV8nl12xFAS0bILA== X-Received: by 2002:a17:90a:1aa9:: with SMTP id p38mr20418659pjp.142.1570824969192; Fri, 11 Oct 2019 13:16:09 -0700 (PDT) Received: from xps15 (S0106002369de4dac.cg.shawcable.net. [68.147.8.254]) by smtp.gmail.com with ESMTPSA id a13sm15525313pfg.10.2019.10.11.13.16.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 11 Oct 2019 13:16:08 -0700 (PDT) Date: Fri, 11 Oct 2019 14:16:06 -0600 From: Mathieu Poirier To: Leo Yan Cc: Arnaldo Carvalho de Melo , Suzuki K Poulose , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mike Leach , Coresight ML , Peter Zijlstra , Ingo Molnar Subject: Re: [PATCH v3 1/6] perf cs-etm: Fix unsigned variable comparison to zero Message-ID: <20191011201606.GC13688@xps15> References: <20191005091614.11635-1-leo.yan@linaro.org> <20191005091614.11635-2-leo.yan@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191005091614.11635-2-leo.yan@linaro.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 05, 2019 at 05:16:09PM +0800, Leo Yan wrote: > If the u64 variable 'offset' is a negative integer, comparison it with > bigger than zero is always going to be true because it is unsigned. > Fix this by using s64 type for variable 'offset'. > > Signed-off-by: Leo Yan > --- > tools/perf/util/cs-etm.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c > index 4ba0f871f086..4bc2d9709d4f 100644 > --- a/tools/perf/util/cs-etm.c > +++ b/tools/perf/util/cs-etm.c > @@ -940,7 +940,7 @@ u64 cs_etm__last_executed_instr(const struct cs_etm_packet *packet) > static inline u64 cs_etm__instr_addr(struct cs_etm_queue *etmq, > u64 trace_chan_id, > const struct cs_etm_packet *packet, > - u64 offset) > + s64 offset) In Suzuki's reply there was two choices, 1) move the while(offset > 0) to while (offset) or change the type of @offset to an s64. Here we know offset can't be negative because of the tidq->period_instructions >= etm->instructions_sample_period in function cs_etm__sample(). As such I think option #1 is the right way to deal with this rather than changing the type of the variable. Mathieu > { > if (packet->isa == CS_ETM_ISA_T32) { > u64 addr = packet->start_addr; > @@ -1372,7 +1372,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, > * sample is reported as though instruction has just been > * executed, but PC has not advanced to next instruction) > */ > - u64 offset = (instrs_executed - instrs_over - 1); > + s64 offset = (instrs_executed - instrs_over - 1); > u64 addr = cs_etm__instr_addr(etmq, trace_chan_id, > tidq->packet, offset); > > -- > 2.17.1 > From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 69B00C47404 for ; Fri, 11 Oct 2019 20:16:14 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 356AD206CD for ; Fri, 11 Oct 2019 20:16:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="osYgot9I"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="Jy+yz6cs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 356AD206CD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ZzoK+iICrNkLRT3DtFwgW27ZaaHjux82gF62uE2eYYs=; b=osYgot9IfxfyoC EfCM8gSSXR5pqDvI/3W8UHfcSDtptqWipQD2pZbAXkwRfY9+UJ9hU4EzUK5n6PErTyWcQAVAxz6lp sgdEmaiByCLmEtVsTbKpyspupHaawTTaNRgipwNnxP8beM7FLrryxdabor3rnNIKNZ5+5krc42g4f HwijqDlxC3aLkq+hXQAWJoQD1JFTddtO5OyGyKsilwqt5A2PEF3arC/oi2KUo9g0dD3Bd5JCkyfxV cidkJl+i52R64uSpdsuuqs4Kc5KMH9oBtOa4bQaaEt/kA3fnL7qJZUr2a7Wr+/ilPbAtl3Lb1PIJQ dUwLFkNUJfduMGldberA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iJ1Kf-0008OC-Oi; Fri, 11 Oct 2019 20:16:13 +0000 Received: from mail-pf1-x444.google.com ([2607:f8b0:4864:20::444]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iJ1Kd-0008NL-Ch for linux-arm-kernel@lists.infradead.org; Fri, 11 Oct 2019 20:16:12 +0000 Received: by mail-pf1-x444.google.com with SMTP id b128so6738547pfa.1 for ; Fri, 11 Oct 2019 13:16:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=PR46YI2RMcoiv8IfiEatQgc8ZaD0QWUbng9pxbLKT2g=; b=Jy+yz6cspKP36E2xWln+kXX+hRDBKhLWAYgzxCz734kBlvsoc9VIusa25mAMklPTjM CGRVYpf1ioSv9f7+fT+hvhHdxgmGqXO2cPhAPSGNWvTKcevKLlnFxEh8pHT5m/v28oXj /n8h7fnbtr0/Y0NfSf5uIU8H6FWYq2NKn2mK9pg+fZ0e6fxC4taVdvdiMQrJb9NukCaL tEYoPdH7J8Pxtx9jcKLwf5U1f53BePopdUr8SwpV/rGTlKek88ROJ562DmbUKQ+E0qN2 7X4+XA73UIIcxTJDul1+A5OjLyPlQsmc0g5IEuSz5U/v67gMJK4fVmS8DQa2p9JVKGot 7F1w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=PR46YI2RMcoiv8IfiEatQgc8ZaD0QWUbng9pxbLKT2g=; b=mKsbwOeKjJtMWxB/0D6zOGk4O7BAlmLfpmxog64PapWyGySWJI9wt7tgNs0lHHcU8C JKj/wuLggwhUS+pcItmcYnQo1wbBqj8rWK2HfiKYwD1TNI8je+hsomHDK5kqHsNooZsz kockuXdwQa0rSAreXMPNihZWNFGGEtEMz5/+hNkLvH5SK2L74mE8t2S3viZBLjWHLctD ee+86CGuRD7UMex56mllSMQ4S9jjaWp830eK6dSE2HVDbLMyFpkR7VTlxz4XzSpiUmBD bfem5oHtmeDmHdEYAUCxdpQX1jYr9Fokli7dmePy7uy3zc0hHigqCoIRmZVHzZIcrD9T X8cg== X-Gm-Message-State: APjAAAWS4+/jpcTTvOyyrzYDy2BptJFW+D50i6IeElGQQxxCrIxhZ7fQ aCcdoAYk8P1EHG26I8OIzDqq4w== X-Google-Smtp-Source: APXvYqwEyiiUYWnxVo/iZMPv/NTiwhPMmTvQy5U8FMYGFAVmjoSfpr6Hd/ZFZ7xV8nl12xFAS0bILA== X-Received: by 2002:a17:90a:1aa9:: with SMTP id p38mr20418659pjp.142.1570824969192; Fri, 11 Oct 2019 13:16:09 -0700 (PDT) Received: from xps15 (S0106002369de4dac.cg.shawcable.net. [68.147.8.254]) by smtp.gmail.com with ESMTPSA id a13sm15525313pfg.10.2019.10.11.13.16.07 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 11 Oct 2019 13:16:08 -0700 (PDT) Date: Fri, 11 Oct 2019 14:16:06 -0600 From: Mathieu Poirier To: Leo Yan Subject: Re: [PATCH v3 1/6] perf cs-etm: Fix unsigned variable comparison to zero Message-ID: <20191011201606.GC13688@xps15> References: <20191005091614.11635-1-leo.yan@linaro.org> <20191005091614.11635-2-leo.yan@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191005091614.11635-2-leo.yan@linaro.org> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191011_131611_434093_F4E87AE7 X-CRM114-Status: GOOD ( 18.13 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Suzuki K Poulose , Alexander Shishkin , Coresight ML , linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Namhyung Kim , Jiri Olsa , linux-arm-kernel@lists.infradead.org, Mike Leach Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Sat, Oct 05, 2019 at 05:16:09PM +0800, Leo Yan wrote: > If the u64 variable 'offset' is a negative integer, comparison it with > bigger than zero is always going to be true because it is unsigned. > Fix this by using s64 type for variable 'offset'. > > Signed-off-by: Leo Yan > --- > tools/perf/util/cs-etm.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c > index 4ba0f871f086..4bc2d9709d4f 100644 > --- a/tools/perf/util/cs-etm.c > +++ b/tools/perf/util/cs-etm.c > @@ -940,7 +940,7 @@ u64 cs_etm__last_executed_instr(const struct cs_etm_packet *packet) > static inline u64 cs_etm__instr_addr(struct cs_etm_queue *etmq, > u64 trace_chan_id, > const struct cs_etm_packet *packet, > - u64 offset) > + s64 offset) In Suzuki's reply there was two choices, 1) move the while(offset > 0) to while (offset) or change the type of @offset to an s64. Here we know offset can't be negative because of the tidq->period_instructions >= etm->instructions_sample_period in function cs_etm__sample(). As such I think option #1 is the right way to deal with this rather than changing the type of the variable. Mathieu > { > if (packet->isa == CS_ETM_ISA_T32) { > u64 addr = packet->start_addr; > @@ -1372,7 +1372,7 @@ static int cs_etm__sample(struct cs_etm_queue *etmq, > * sample is reported as though instruction has just been > * executed, but PC has not advanced to next instruction) > */ > - u64 offset = (instrs_executed - instrs_over - 1); > + s64 offset = (instrs_executed - instrs_over - 1); > u64 addr = cs_etm__instr_addr(etmq, trace_chan_id, > tidq->packet, offset); > > -- > 2.17.1 > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel