Commit 7bd50ccf authored by Mathieu Poirier's avatar Mathieu Poirier Committed by Greg Kroah-Hartman

coresight: etm3x: Don't use contextID with PID namespaces

Tracers can trigger trace acquisition based on contextID value, something
that isn't useful when PID namespaces are enabled.  Indeed the PID value
of a process has a different representation in the kernel and the PID
namespace, making the feature confusing and potentially leaking internal
kernel information.

As such simply return an error when the feature is being used from a
PID namespace other than the default one.
Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Reviewed-by: default avatarKim Phillips <kim.phillips@arm.com>
Acked-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5151e2b5
...@@ -168,8 +168,6 @@ ...@@ -168,8 +168,6 @@
* @seq_curr_state: current value of the sequencer register. * @seq_curr_state: current value of the sequencer register.
* @ctxid_idx: index for the context ID registers. * @ctxid_idx: index for the context ID registers.
* @ctxid_pid: value for the context ID to trigger on. * @ctxid_pid: value for the context ID to trigger on.
* @ctxid_vpid: Virtual PID seen by users if PID namespace is enabled, otherwise
* the same value of ctxid_pid.
* @ctxid_mask: mask applicable to all the context IDs. * @ctxid_mask: mask applicable to all the context IDs.
* @sync_freq: Synchronisation frequency. * @sync_freq: Synchronisation frequency.
* @timestamp_event: Defines an event that requests the insertion * @timestamp_event: Defines an event that requests the insertion
...@@ -202,7 +200,6 @@ struct etm_config { ...@@ -202,7 +200,6 @@ struct etm_config {
u32 seq_curr_state; u32 seq_curr_state;
u8 ctxid_idx; u8 ctxid_idx;
u32 ctxid_pid[ETM_MAX_CTXID_CMP]; u32 ctxid_pid[ETM_MAX_CTXID_CMP];
u32 ctxid_vpid[ETM_MAX_CTXID_CMP];
u32 ctxid_mask; u32 ctxid_mask;
u32 sync_freq; u32 sync_freq;
u32 timestamp_event; u32 timestamp_event;
......
...@@ -4,6 +4,7 @@ ...@@ -4,6 +4,7 @@
* Author: Mathieu Poirier <mathieu.poirier@linaro.org> * Author: Mathieu Poirier <mathieu.poirier@linaro.org>
*/ */
#include <linux/pid_namespace.h>
#include <linux/pm_runtime.h> #include <linux/pm_runtime.h>
#include <linux/sysfs.h> #include <linux/sysfs.h>
#include "coresight-etm.h" #include "coresight-etm.h"
...@@ -1025,8 +1026,15 @@ static ssize_t ctxid_pid_show(struct device *dev, ...@@ -1025,8 +1026,15 @@ static ssize_t ctxid_pid_show(struct device *dev,
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
struct etm_config *config = &drvdata->config; struct etm_config *config = &drvdata->config;
/*
* Don't use contextID tracing if coming from a PID namespace. See
* comment in ctxid_pid_store().
*/
if (task_active_pid_ns(current) != &init_pid_ns)
return -EINVAL;
spin_lock(&drvdata->spinlock); spin_lock(&drvdata->spinlock);
val = config->ctxid_vpid[config->ctxid_idx]; val = config->ctxid_pid[config->ctxid_idx];
spin_unlock(&drvdata->spinlock); spin_unlock(&drvdata->spinlock);
return sprintf(buf, "%#lx\n", val); return sprintf(buf, "%#lx\n", val);
...@@ -1037,19 +1045,28 @@ static ssize_t ctxid_pid_store(struct device *dev, ...@@ -1037,19 +1045,28 @@ static ssize_t ctxid_pid_store(struct device *dev,
const char *buf, size_t size) const char *buf, size_t size)
{ {
int ret; int ret;
unsigned long vpid, pid; unsigned long pid;
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
struct etm_config *config = &drvdata->config; struct etm_config *config = &drvdata->config;
ret = kstrtoul(buf, 16, &vpid); /*
* When contextID tracing is enabled the tracers will insert the
* value found in the contextID register in the trace stream. But if
* a process is in a namespace the PID of that process as seen from the
* namespace won't be what the kernel sees, something that makes the
* feature confusing and can potentially leak kernel only information.
* As such refuse to use the feature if @current is not in the initial
* PID namespace.
*/
if (task_active_pid_ns(current) != &init_pid_ns)
return -EINVAL;
ret = kstrtoul(buf, 16, &pid);
if (ret) if (ret)
return ret; return ret;
pid = coresight_vpid_to_pid(vpid);
spin_lock(&drvdata->spinlock); spin_lock(&drvdata->spinlock);
config->ctxid_pid[config->ctxid_idx] = pid; config->ctxid_pid[config->ctxid_idx] = pid;
config->ctxid_vpid[config->ctxid_idx] = vpid;
spin_unlock(&drvdata->spinlock); spin_unlock(&drvdata->spinlock);
return size; return size;
...@@ -1063,6 +1080,13 @@ static ssize_t ctxid_mask_show(struct device *dev, ...@@ -1063,6 +1080,13 @@ static ssize_t ctxid_mask_show(struct device *dev,
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
struct etm_config *config = &drvdata->config; struct etm_config *config = &drvdata->config;
/*
* Don't use contextID tracing if coming from a PID namespace. See
* comment in ctxid_pid_store().
*/
if (task_active_pid_ns(current) != &init_pid_ns)
return -EINVAL;
val = config->ctxid_mask; val = config->ctxid_mask;
return sprintf(buf, "%#lx\n", val); return sprintf(buf, "%#lx\n", val);
} }
...@@ -1076,6 +1100,13 @@ static ssize_t ctxid_mask_store(struct device *dev, ...@@ -1076,6 +1100,13 @@ static ssize_t ctxid_mask_store(struct device *dev,
struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent); struct etm_drvdata *drvdata = dev_get_drvdata(dev->parent);
struct etm_config *config = &drvdata->config; struct etm_config *config = &drvdata->config;
/*
* Don't use contextID tracing if coming from a PID namespace. See
* comment in ctxid_pid_store().
*/
if (task_active_pid_ns(current) != &init_pid_ns)
return -EINVAL;
ret = kstrtoul(buf, 16, &val); ret = kstrtoul(buf, 16, &val);
if (ret) if (ret)
return ret; return ret;
......
...@@ -230,10 +230,8 @@ void etm_set_default(struct etm_config *config) ...@@ -230,10 +230,8 @@ void etm_set_default(struct etm_config *config)
config->seq_curr_state = 0x0; config->seq_curr_state = 0x0;
config->ctxid_idx = 0x0; config->ctxid_idx = 0x0;
for (i = 0; i < ETM_MAX_CTXID_CMP; i++) { for (i = 0; i < ETM_MAX_CTXID_CMP; i++)
config->ctxid_pid[i] = 0x0; config->ctxid_pid[i] = 0x0;
config->ctxid_vpid[i] = 0x0;
}
config->ctxid_mask = 0x0; config->ctxid_mask = 0x0;
/* Setting default to 1024 as per TRM recommendation */ /* Setting default to 1024 as per TRM recommendation */
......
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