Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754345Ab1BOGMx (ORCPT ); Tue, 15 Feb 2011 01:12:53 -0500 Received: from mail-pz0-f46.google.com ([209.85.210.46]:46533 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752715Ab1BOGL7 (ORCPT ); Tue, 15 Feb 2011 01:11:59 -0500 From: =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= To: linux-arm-kernel@lists.infradead.org Cc: linux-omap@vger.kernel.org, =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= , Russell King , Alexander Shishkin , Jason Wessel , Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: [PATCH 6/8] ARM: etm: Add some missing locks and error checks Date: Mon, 14 Feb 2011 22:11:14 -0800 Message-Id: <1297750276-12475-6-git-send-email-arve@android.com> X-Mailer: git-send-email 1.7.3.1 In-Reply-To: <1296701663-12168-1-git-send-email-arve@android.com> References: <1296701663-12168-1-git-send-email-arve@android.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4421 Lines: 153 It is not safe to call etm_lock or etb_lock without holding the mutex since another thread may also have unlocked the registers. Also add some missing checks for valid etb_regs in the etm sysfs entries. Signed-off-by: Arve Hjønnevåg --- arch/arm/kernel/etm.c | 57 +++++++++++++++++++++++++++++++++--------------- 1 files changed, 39 insertions(+), 18 deletions(-) diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c index 96b1abb..8126beb 100644 --- a/arch/arm/kernel/etm.c +++ b/arch/arm/kernel/etm.c @@ -263,8 +263,13 @@ static void etm_dump(void) static void sysrq_etm_dump(int key) { + if (!mutex_trylock(&tracer.mutex)) { + printk(KERN_INFO "Tracing hardware busy\n"); + return; + } dev_dbg(tracer.dev, "Dumping ETB buffer\n"); etm_dump(); + mutex_unlock(&tracer.mutex); } static struct sysrq_key_op sysrq_etm_op = { @@ -373,6 +378,7 @@ static int __init etb_probe(struct amba_device *dev, struct amba_id *id) if (ret) goto out; + mutex_lock(&t->mutex); t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res)); if (!t->etb_regs) { ret = -ENOMEM; @@ -381,6 +387,16 @@ static int __init etb_probe(struct amba_device *dev, struct amba_id *id) amba_set_drvdata(dev, t); + etb_unlock(t); + t->etb_bufsz = etb_readl(t, ETBR_DEPTH); + dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz); + + /* make sure trace capture is disabled */ + etb_writel(t, 0, ETBR_CTRL); + etb_writel(t, 0x1000, ETBR_FORMATTERCTRL); + etb_lock(t); + mutex_unlock(&t->mutex); + etb_miscdev.parent = &dev->dev; ret = misc_register(&etb_miscdev); @@ -394,25 +410,19 @@ static int __init etb_probe(struct amba_device *dev, struct amba_id *id) else clk_enable(t->emu_clk); - etb_unlock(t); - t->etb_bufsz = etb_readl(t, ETBR_DEPTH); - dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz); - - /* make sure trace capture is disabled */ - etb_writel(t, 0, ETBR_CTRL); - etb_writel(t, 0x1000, ETBR_FORMATTERCTRL); - etb_lock(t); - dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n"); out: return ret; out_unmap: + mutex_lock(&t->mutex); amba_set_drvdata(dev, NULL); iounmap(t->etb_regs); + t->etb_regs = NULL; out_release: + mutex_unlock(&t->mutex); amba_release_regions(dev); return ret; @@ -474,7 +484,10 @@ static ssize_t trace_running_store(struct kobject *kobj, return -EINVAL; mutex_lock(&tracer.mutex); - ret = value ? trace_start(&tracer) : trace_stop(&tracer); + if (!tracer.etb_regs) + ret = -ENODEV; + else + ret = value ? trace_start(&tracer) : trace_stop(&tracer); mutex_unlock(&tracer.mutex); return ret ? : n; @@ -490,18 +503,25 @@ static ssize_t trace_info_show(struct kobject *kobj, u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st; int datalen; - etb_unlock(&tracer); - datalen = etb_getdatalen(&tracer); - etb_wa = etb_readl(&tracer, ETBR_WRITEADDR); - etb_ra = etb_readl(&tracer, ETBR_READADDR); - etb_st = etb_readl(&tracer, ETBR_STATUS); - etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL); - etb_lock(&tracer); + mutex_lock(&tracer.mutex); + if (tracer.etb_regs) { + etb_unlock(&tracer); + datalen = etb_getdatalen(&tracer); + etb_wa = etb_readl(&tracer, ETBR_WRITEADDR); + etb_ra = etb_readl(&tracer, ETBR_READADDR); + etb_st = etb_readl(&tracer, ETBR_STATUS); + etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL); + etb_lock(&tracer); + } else { + etb_wa = etb_ra = etb_st = etb_fc = ~0; + datalen = -1; + } etm_unlock(&tracer); etm_ctrl = etm_readl(&tracer, ETMR_CTRL); etm_st = etm_readl(&tracer, ETMR_STATUS); etm_lock(&tracer); + mutex_unlock(&tracer.mutex); return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n" "ETBR_WRITEADDR:\t%08x\n" @@ -651,7 +671,6 @@ static int __init etm_probe(struct amba_device *dev, struct amba_id *id) amba_set_drvdata(dev, t); - mutex_init(&t->mutex); t->dev = &dev->dev; t->flags = TRACER_CYCLE_ACC | TRACER_TRACE_DATA; t->etm_portsz = 1; @@ -745,6 +764,8 @@ static int __init etm_init(void) { int retval; + mutex_init(&tracer.mutex); + retval = amba_driver_register(&etb_driver); if (retval) { printk(KERN_ERR "Failed to register etb\n"); -- 1.7.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/