From 140b361c6ac14976fd7b1d5a0fd21c2e9da3ae61 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= Date: Mon, 14 Feb 2011 21:09:51 -0800 Subject: [PATCH] ARM: etm: Add some missing locks and error checks MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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. Change-Id: I939f76a6ea7546a8fc0d4ddafa2fd2b6f38103bb Signed-off-by: Arve Hjønnevåg --- arch/arm/kernel/etm.c | 57 +++++++++++++++++++++++++++++-------------- 1 file changed, 39 insertions(+), 18 deletions(-) diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c index b5f5aadf6f0a..2dac2bdafeef 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 __devinit etb_probe(struct amba_device *dev, const 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 __devinit etb_probe(struct amba_device *dev, const 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 __devinit etb_probe(struct amba_device *dev, const 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 __devinit etm_probe(struct amba_device *dev, const 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"); -- 2.39.5