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Date: Thu, 30 Jan 2014 11:11:10 -0500
From: Adrien Vergé <adrienverge@...il.com>
To: Russell King <linux@....linux.org.uk>
Cc: Adrien Vergé <adrienverge@...il.com>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Ben Dooks <ben.dooks@...ethink.co.uk>,
"zhangwei(Jovi)" <jovi.zhangwei@...wei.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Randy Dunlap <rdunlap@...radead.org>,
Mathieu Poirier <mathieu.poirier@...aro.org>,
Christopher Covington <cov@...eaurora.org>,
Dirk Behme <dirk.behme@...bosch.com>,
Michel Dagenais <michel.dagenais@...ymtl.ca>,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH V3 5/5] ARM CoreSight: ETM: Add PID control support
In the same manner as for enabling tracing, an entry is created in
sysfs to set the PID that triggers tracing. This change is effective
only if CONFIG_PID_IN_CONTEXTIDR is set.
When using PID namespaces, the virtual PID given by the user is
converted to the globally unique ID (task_pid_nr) that is present
in the Context ID register.
Signed-off-by: Adrien Vergé <adrienverge@...il.com>
---
arch/arm/include/asm/hardware/coresight.h | 5 ++
arch/arm/kernel/etm.c | 131 ++++++++++++++++++++++++++++--
2 files changed, 129 insertions(+), 7 deletions(-)
diff --git a/arch/arm/include/asm/hardware/coresight.h b/arch/arm/include/asm/hardware/coresight.h
index 8c50cf6..2051af0 100644
--- a/arch/arm/include/asm/hardware/coresight.h
+++ b/arch/arm/include/asm/hardware/coresight.h
@@ -98,6 +98,11 @@
#define ETMR_ADDRCOMP_VAL(x) (0x40 + (x) * 4)
#define ETMR_ADDRCOMP_ACC_TYPE(x) (0x80 + (x) * 4)
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+#define ETMR_CTXIDCOMP_VAL(x) (0x1b0 + (x) * 4)
+#define ETMR_CTXIDCOMP_MASK (0x1bc)
+#endif
+
/* ETM status register, "ETM Architecture", 3.3.2 */
#define ETMR_STATUS (0x10)
#define ETMST_OVERFLOW BIT(0)
diff --git a/arch/arm/kernel/etm.c b/arch/arm/kernel/etm.c
index fa42e32..e8db9e2 100644
--- a/arch/arm/kernel/etm.c
+++ b/arch/arm/kernel/etm.c
@@ -25,6 +25,7 @@
#include <linux/vmalloc.h>
#include <linux/mutex.h>
#include <linux/module.h>
+#include <linux/sched.h>
#include <asm/hardware/coresight.h>
#include <asm/sections.h>
@@ -40,12 +41,17 @@ struct tracectx {
void __iomem *etm_regs;
unsigned long flags;
int naddrcmppairs;
+ int nctxidcmp;
int etm_portsz;
struct device *dev;
struct clk *emu_clk;
struct mutex mutex;
unsigned long addrrange_start;
unsigned long addrrange_end;
+ pid_t pid; /* globally unique PID */
+#ifdef CONFIG_PID_NS
+ pid_t vpid; /* virtual PID as seen in namespace */
+#endif
};
static struct tracectx tracer;
@@ -55,18 +61,42 @@ static inline bool trace_isrunning(struct tracectx *t)
return !!(t->flags & TRACER_RUNNING);
}
+#if defined(CONFIG_PID_IN_CONTEXTIDR) && defined(CONFIG_PID_NS)
+/*
+ * Returns the globally unique ID of a task referenced
+ * with its virtual namespace PID
+ */
+static inline pid_t pid_vnr_to_pid_nr(pid_t vpid)
+{
+ struct task_struct *task = find_task_by_vpid(vpid);
+
+ if (!task) {
+ printk(KERN_WARNING "CoreSight ETM: cannot track PID %d: "
+ "no such PID in current namespace\n",
+ vpid);
+ return -EINVAL;
+ }
+
+ return task_pid_nr(task);
+}
+#endif
+
/*
* Setups ETM to trace only when:
* - address between start and end
* or address not between start and end (if exclude)
+ * - in user-space when process id equals pid,
+ * in kernel-space (if pid == 0),
+ * always (if pid == -1)
* - trace executed instructions
* or trace loads and stores (if data)
*/
-static int etm_setup_address_range(struct tracectx *t, int n,
- unsigned long start, unsigned long end, int exclude, int data)
+static int etm_setup(struct tracectx *t, int n,
+ unsigned long start, unsigned long end, int exclude,
+ pid_t pid,
+ int data)
{
- u32 flags = ETMAAT_ARM | ETMAAT_IGNCONTEXTID | ETMAAT_NSONLY | \
- ETMAAT_NOVALCMP;
+ u32 flags = ETMAAT_ARM | ETMAAT_NSONLY | ETMAAT_NOVALCMP;
if (n < 1 || n > t->naddrcmppairs)
return -EINVAL;
@@ -75,6 +105,23 @@ static int etm_setup_address_range(struct tracectx *t, int n,
* to bits in a word */
n--;
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+ if (pid < 0) {
+ /* ignore Context ID */
+ flags |= ETMAAT_IGNCONTEXTID;
+ } else {
+ flags |= ETMAAT_VALUE1;
+
+ /* Set up the first Context ID comparator.
+ Process ID is found in the 24 first bits of Context ID
+ (provided by CONFIG_PID_IN_CONTEXTIDR) */
+ etm_writel(t, pid << 8, ETMR_CTXIDCOMP_VAL(0));
+ etm_writel(t, 0xff, ETMR_CTXIDCOMP_MASK);
+ }
+#else
+ flags |= ETMAAT_IGNCONTEXTID;
+#endif
+
if (data)
flags |= ETMAAT_DLOADSTORE;
else
@@ -124,8 +171,10 @@ static int trace_start(struct tracectx *t)
return -EFAULT;
}
- etm_setup_address_range(t, 1, t->addrrange_start, t->addrrange_end,
- 0, 0);
+ etm_setup(t, 1,
+ t->addrrange_start, t->addrrange_end, 0,
+ t->pid,
+ 0);
etm_writel(t, 0, ETMR_TRACEENCTRL2);
etm_writel(t, 0, ETMR_TRACESSCTRL);
etm_writel(t, 0x6f, ETMR_TRACEENEVT);
@@ -489,6 +538,7 @@ static ssize_t trace_info_show(struct device *dev,
return sprintf(buf, "Trace buffer len: %d\n"
"Addr comparator pairs: %d\n"
+ "Ctx ID comparators: %d\n"
"ETBR_WRITEADDR:\t%08x\n"
"ETBR_READADDR:\t%08x\n"
"ETBR_STATUS:\t%08x\n"
@@ -497,6 +547,7 @@ static ssize_t trace_info_show(struct device *dev,
"ETMR_STATUS:\t%08x\n",
datalen,
tracer.naddrcmppairs,
+ tracer.nctxidcmp,
etb_wa,
etb_ra,
etb_st,
@@ -569,6 +620,61 @@ static ssize_t trace_addrrange_store(struct device *dev,
DEVICE_ATTR(trace_addrrange, S_IRUGO|S_IWUSR,
trace_addrrange_show, trace_addrrange_store);
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+static ssize_t trace_pid_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+#ifdef CONFIG_PID_NS
+ return sprintf(buf, "%d\n", tracer.vpid);
+#else
+ return sprintf(buf, "%d\n", tracer.pid);
+#endif
+}
+
+static ssize_t trace_pid_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t n)
+{
+ pid_t pid;
+#ifdef CONFIG_PID_NS
+ pid_t vpid;
+#endif
+
+ if (tracer.flags & TRACER_RUNNING)
+ return -EBUSY;
+
+ if (sscanf(buf, "%i", &pid) != 1)
+ return -EINVAL;
+
+#ifdef CONFIG_PID_NS
+ /* the value written to the Context ID register is the global PID */
+ vpid = pid;
+
+ /* -1 means trace everything,
+ 0 means kernel tracing,
+ > 0 process tracing */
+ if (pid > 0) {
+ pid = pid_vnr_to_pid_nr(vpid);
+
+ if (pid < 0)
+ return pid;
+ }
+#endif
+
+ mutex_lock(&tracer.mutex);
+ tracer.pid = pid;
+#ifdef CONFIG_PID_NS
+ tracer.vpid = vpid;
+#endif
+ mutex_unlock(&tracer.mutex);
+
+ return n;
+}
+
+DEVICE_ATTR(trace_pid, S_IRUGO|S_IWUSR, trace_pid_show, trace_pid_store);
+#endif
+
static int etm_probe(struct amba_device *dev, const struct amba_id *id)
{
struct tracectx *t = &tracer;
@@ -598,6 +704,7 @@ static int etm_probe(struct amba_device *dev, const struct amba_id *id)
t->etm_portsz = 1;
t->addrrange_start = (unsigned long) _stext;
t->addrrange_end = (unsigned long) _etext;
+ t->pid = -1; /* trace everything */
etm_unlock(t);
(void)etm_readl(t, ETMMR_PDSR);
@@ -605,6 +712,7 @@ static int etm_probe(struct amba_device *dev, const struct amba_id *id)
(void)etm_readl(&tracer, ETMMR_OSSRR);
t->naddrcmppairs = etm_readl(t, ETMR_CONFCODE) & 0xf;
+ t->nctxidcmp = (etm_readl(t, ETMR_CONFCODE) >> 24) & 0x3;
etm_writel(t, 0x440, ETMR_CTRL);
etm_lock(t);
@@ -612,7 +720,7 @@ static int etm_probe(struct amba_device *dev, const struct amba_id *id)
if (ret)
goto out_unmap;
- /* failing to create any of these three is not fatal */
+ /* failing to create any of these four is not fatal */
ret = device_create_file(&dev->dev, &dev_attr_trace_info);
if (ret)
dev_dbg(&dev->dev, "Failed to create trace_info in sysfs\n");
@@ -625,6 +733,12 @@ static int etm_probe(struct amba_device *dev, const struct amba_id *id)
if (ret)
dev_dbg(&dev->dev, "Failed to create trace_addrrange in sysfs\n");
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+ ret = device_create_file(&dev->dev, &dev_attr_trace_pid);
+ if (ret)
+ dev_dbg(&dev->dev, "Failed to create trace_pid in sysfs\n");
+#endif
+
dev_dbg(t->dev, "ETM AMBA driver initialized.\n");
out:
@@ -655,6 +769,9 @@ static int etm_remove(struct amba_device *dev)
device_remove_file(&dev->dev, &dev_attr_trace_info);
device_remove_file(&dev->dev, &dev_attr_trace_mode);
device_remove_file(&dev->dev, &dev_attr_trace_addrrange);
+#ifdef CONFIG_PID_IN_CONTEXTIDR
+ device_remove_file(&dev->dev, &dev_attr_trace_pid);
+#endif
return 0;
}
--
1.8.5.3
--
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