From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1522701367; cv=none; d=google.com; s=arc-20160816; b=SqIngtYgmO4Tbp+1Yr1zt1JUYRRW8/UCibErvD2r2I094hzpSEXt8qvf9rPD0orWaG 65+1/+YQTaFaMSI8jvL/83uAkUtN3QoRJB65TMlHmgjdokRUEcxczKpdvvqCygGLG/xX 2m81ZqQbKMlUrYSiraEu4WrwTlOzq9Z0Ax0EgQxoIDofPbYSYXM4b7hnk40yrWwXo6wR qBLNxRxFYBOLmcfMfL7stqHBBbDpv0FsYQbhjTKoc15byOXEcs+0uZdY6hfNdeR91a5L h4FcGEAsnV6H3SJriKDtZnJTub5ztqJa3BBe6UhwdSMDlsjoILnhdK5TMgeoUshnsK2X ZOXA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature :arc-authentication-results; bh=U+gYwYEsk5Cnl+UDCu4TBUGdDz9cAC2GgRFKIj0Mx48=; b=A1Uqjkj/hVKNIXQKHnIH/VOU4bcod6lPOVDqMi17aAdOXcc222ig3NfKrU+okCgedZ 4+h7TT9frQLKm7o1dh1tRw2mVCUuhX6qLhWQLICTHcrM9yUGl6W7Vq4tdJpvG7XkL95v kaOC9c6IcCMlAI5thmS4wmeMA13+N2yWCq0FeHIGS7+PJX44PEPR1Vk+Gj4OOh1vc8d/ VCnNDOlUoG4kiJ60HPBYjCn1fHdNxMCN1z682lCk9EiFSG5Nedr7DdyUhuay8EdoqxHb q8fFBs9E73ocQjrvmjPRGhXIk7vs8lpfRnUoS6/QLwS2x08eAb+8BU/NILyNZ3a1cS+B OOlw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=Itxg5uSc; spf=pass (google.com: domain of mathieu.poirier@linaro.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=mathieu.poirier@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=Itxg5uSc; spf=pass (google.com: domain of mathieu.poirier@linaro.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=mathieu.poirier@linaro.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org X-Google-Smtp-Source: AIpwx4+U+ooFS55FzRW+rfQ20PoxbRJRuFS10W6Z7Mi3kecYptB0CQeq7tduj78qiFMmM6Lzet5Nvw== Date: Mon, 2 Apr 2018 14:36:04 -0600 From: Mathieu Poirier To: Leo Yan Cc: Jonathan Corbet , Greg Kroah-Hartman , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, coresight@lists.linaro.org, Kim Phillips , Mike Leach Subject: Re: [PATCH v4 4/6] coresight: tmc: Hook callback for panic kdump Message-ID: <20180402203604.GD15452@xps15> References: <1522379724-30648-1-git-send-email-leo.yan@linaro.org> <1522379724-30648-5-git-send-email-leo.yan@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1522379724-30648-5-git-send-email-leo.yan@linaro.org> User-Agent: Mutt/1.5.24 (2015-08-30) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1596330884321271490?= X-GMAIL-MSGID: =?utf-8?q?1596668109933865205?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Fri, Mar 30, 2018 at 11:15:22AM +0800, Leo Yan wrote: > Since Coresight panic kdump functionality has been ready, this patch is > to hook panic callback function for ETB/ETF driver. The driver data > structure has allocated a buffer when the session started, so simply > save tracing data into this buffer when panic happens and update buffer > related info for kdump. > > Signed-off-by: Leo Yan > --- > drivers/hwtracing/coresight/coresight-tmc-etf.c | 30 +++++++++++++++++++++++++ > 1 file changed, 30 insertions(+) > > diff --git a/drivers/hwtracing/coresight/coresight-tmc-etf.c b/drivers/hwtracing/coresight/coresight-tmc-etf.c > index e2513b7..d20d546 100644 > --- a/drivers/hwtracing/coresight/coresight-tmc-etf.c > +++ b/drivers/hwtracing/coresight/coresight-tmc-etf.c > @@ -504,6 +504,35 @@ static void tmc_update_etf_buffer(struct coresight_device *csdev, > CS_LOCK(drvdata->base); > } > > +static void tmc_panic_cb(void *data) I would call the function tmc_kdump_panic_cb()... That way there is absolutely no confusion as to what it does. > +{ > + struct coresight_device *csdev = (struct coresight_device *)data; > + struct tmc_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent); > + unsigned long flags; > + > + if (WARN_ON_ONCE(drvdata->config_type != TMC_CONFIG_TYPE_ETB && > + drvdata->config_type != TMC_CONFIG_TYPE_ETF)) > + return; > + > + if (drvdata->mode == CS_MODE_DISABLED) > + return; This is racy - between the check and acquiring the spinlock someone may beat you to it. > + > + spin_lock_irqsave(&drvdata->spinlock, flags); if (drvdata->mode == CS_MODE_DISABLED) goto out; drvdata->mode = CS_MODE_DISABLED > + > + CS_UNLOCK(drvdata->base); > + > + tmc_flush_and_stop(drvdata); > + tmc_etb_dump_hw(drvdata); > + > + CS_LOCK(drvdata->base); > + > + /* Update buffer info for panic dump */ > + csdev->kdump_buf = drvdata->buf; > + csdev->kdump_buf_sz = drvdata->len; out: > + > + spin_unlock_irqrestore(&drvdata->spinlock, flags); > +} > + > static const struct coresight_ops_sink tmc_etf_sink_ops = { > .enable = tmc_enable_etf_sink, > .disable = tmc_disable_etf_sink, > @@ -512,6 +541,7 @@ static const struct coresight_ops_sink tmc_etf_sink_ops = { > .set_buffer = tmc_set_etf_buffer, > .reset_buffer = tmc_reset_etf_buffer, > .update_buffer = tmc_update_etf_buffer, > + .panic_cb = tmc_panic_cb, > }; > > static const struct coresight_ops_link tmc_etf_link_ops = { > -- > 2.7.4 >