Now that the default framing protocol is factored out into its own driver,
switch over to using the driver for writing data. To that end, make the
policy code require a valid protocol name (or absence thereof, which is
equivalent to "p_basic").
Also, to make transition easier, make stm class request "p_basic" module
at initialization time.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a helper to write a sequence of bytes as STP data packets. This
is used by protocol drivers to output their metadata, as well as the
actual data payload.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
At the moment, the stm class applies a certain STP framing pattern to
the data as it is written to the underlying STM device. In order to
allow different framing patterns (aka protocols), this patch introduces
the concept of STP protocol drivers, defines data structures and APIs
for the protocol drivers to use.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, if no matching policy node can be found for a trace source,
we'll try to use "default" policy node, then, if that doesn't exist,
we'll pick the first node, in order of creation. If that also fails,
we'll allocate M/C range from the beginning of the device's M/C range.
This makes it difficult to know which node (if any) was used in any
particular case.
In order to make things more deterministic, the new order is as follows:
* if they supply ID string, use that and nothing else,
* if they are a task, use their task name (comm),
* use "default", if it exists,
* return failure, to let them know there is no suitable rule.
This should provide enough convenience with the "default" catch-all node,
while not leaving *everything* to chance. As a side effect, this relaxes
the requirement of using ioctl() for identification with the possibility of
using task names as policy nodes.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit b5e2ced9bf ("stm class: Use vmalloc for the master map") caused
a build error on some arches as vmalloc.h was not explicitly included.
Fix that by adding it to the list of includes.
Fixes: b5e2ced9bf ("stm class: Use vmalloc for the master map")
Reported-by: kbuild test robot <lkp@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fengguang is running into a warning from the buddy allocator:
> swapper/0: page allocation failure: order:9, mode:0x14040c0(GFP_KERNEL|__GFP_COMP), nodemask=(null)
> CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.17.0-rc1 #262
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
> Call Trace:
...
> __kmalloc+0x14b/0x180: ____cache_alloc at mm/slab.c:3127
> stm_register_device+0xf3/0x5c0: stm_register_device at drivers/hwtracing/stm/core.c:695
...
Which is basically a result of the stm class trying to allocate ~512kB
for the dummy_stm with its default parameters. There's no reason, however,
for it not to be vmalloc()ed instead, which is what this patch does.
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
CC: stable@vger.kernel.org # v4.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This adds SPDX GPL-2.0 header to to stm core files and removes the
GPLv2 boilerplate text.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
For reasons unknown, the stm_source removal path uses device_destroy()
to kill the underlying device object. Because device_destroy() uses
devt to look for the device to destroy and the fact that stm_source
devices don't have one (or all have the same one), it just picks the
first device in the class, which may well be the wrong one.
That is, loading stm_console and stm_heartbeat and then removing both
will die in dereferencing a freed object.
Since this should have been device_unregister() in the first place,
use it instead of device_destroy().
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Fixes: 7bd1d4093c ("stm class: Introduce an abstraction for System Trace Module devices")
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The "size" variable comes from the user so we need to verify that it's
large enough to hold an stp_policy_id struct.
Fixes: 7bd1d4093c ("stm class: Introduce an abstraction for System Trace Module devices")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
o STM can hook into the function tracer
o Function filtering now supports more advance glob matching
o Ftrace selftests updates and added tests
o Softirq tag in traces now show only softirqs
o ARM nop added to non traced locations at compile time
o New trace_marker_raw file that allows for binary input
o Optimizations to the ring buffer
o Removal of kmap in trace_marker
o Wakeup and irqsoff tracers now adhere to the set_graph_notrace file
o Other various fixes and clean ups
Note, there are two patches marked for stable. These were discovered
near the end of the 4.9 rc release cycle. By the time I had them tested
it was just a matter of days before 4.9 would be released, and I
figured I would just submit them in the merge window. They are old
bugs and not critical. Nothing non-root could abuse.
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Merge tag 'trace-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This release has a few updates:
- STM can hook into the function tracer
- Function filtering now supports more advance glob matching
- Ftrace selftests updates and added tests
- Softirq tag in traces now show only softirqs
- ARM nop added to non traced locations at compile time
- New trace_marker_raw file that allows for binary input
- Optimizations to the ring buffer
- Removal of kmap in trace_marker
- Wakeup and irqsoff tracers now adhere to the set_graph_notrace file
- Other various fixes and clean ups"
* tag 'trace-v4.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (42 commits)
selftests: ftrace: Shift down default message verbosity
kprobes/trace: Fix kprobe selftest for newer gcc
tracing/kprobes: Add a helper method to return number of probe hits
tracing/rb: Init the CPU mask on allocation
tracing: Use SOFTIRQ_OFFSET for softirq dectection for more accurate results
tracing/fgraph: Have wakeup and irqsoff tracers ignore graph functions too
fgraph: Handle a case where a tracer ignores set_graph_notrace
tracing: Replace kmap with copy_from_user() in trace_marker writing
ftrace/x86_32: Set ftrace_stub to weak to prevent gcc from using short jumps to it
tracing: Allow benchmark to be enabled at early_initcall()
tracing: Have system enable return error if one of the events fail
tracing: Do not start benchmark on boot up
tracing: Have the reg function allow to fail
ring-buffer: Force rb_end_commit() and rb_set_commit_to_write() inline
ring-buffer: Froce rb_update_write_stamp() to be inlined
ring-buffer: Force inline of hotpath helper functions
tracing: Make __buffer_unlock_commit() always_inline
tracing: Make tracepoint_printk a static_key
ring-buffer: Always inline rb_event_data()
ring-buffer: Make rb_reserve_next_event() always inlined
...
If CONFIG_STM_SOURCE_FTRACE is selected, Function trace data can be
writen to sink via STM, all functions that related to writing data
packets to STM should be marked 'notrace' to avoid being traced by
Ftrace, otherwise the program would stall into an endless loop.
Link: http://lkml.kernel.org/r/1479715043-6534-7-git-send-email-zhang.chunyan@linaro.org
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Make sure to drop the reference taken by class_find_device() also on
allocation errors in open().
Signed-off-by: Johan Hovold <johan@kernel.org>
Fixes: 7bd1d4093c ("stm class: Introduce an abstraction for...")
Cc: stable@vger.kernel.org # v4.6+
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Currently, there's no runtime pm in stm class devices, which makes it
harder for the underlying hardware drivers to handle their power
management.
This patch applies the following runtime pm policy to stm class devices,
which their parents can rely on for their power management tracking:
* device is in use during character device writes,
* delayed autosuspend is used to keep it active between adjacent
writes,
* device is in use while mmio regions are mapped,
* device is is use while any stm_source devices are linked to it.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Chunyan Zhang <zhang.chunyan@linaro.org>
Some STM devices adjust software assigned master numbers depending on
the trace source and its runtime state and whatnot. This patch adds
a sysfs attribute to inform the trace-side software that master numbers
assigned to software sources will not match those in the STP stream,
so that, for example, master/channel allocation policy can be adjusted
accordingly.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, stm_register_device() makes the device visible and then
proceeds to initializing spinlocks and other properties, which leaves
a window when the device can already be opened but is not yet fully
operational.
Fix this by reversing the initialization order.
Reported-by: Alan Cox <alan.cox@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
Currently, the error path of stm_register_device() forgets to unregister
the chrdev. Fix this.
Reported-by: Alan Cox <alan.cox@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
No point in explicitly setting something to zero right after we
explicitly checked that it is zero. Fix this.
Reported-by: Alan Cox <alan.cox@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Laurent Fert <laurent.fert@intel.com>
STM device's unlink callback is never actually called from anywhere in
the stm class code.
This patch adds calls to stm driver's unlink method after the unlinking
has succeeded.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There is a window in stm_source_link_drop(), during which the source's
link may change before locks are acquired. When this happens, it throws
a warning, since this is not an expected scenario.
This patch handles the race in such a way that if the link appears to
have changed by the time we took the locks, it will release them and
repeat the whole unlinking procedure from the beginning, unless the
other contender beat us to it.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
STM code takes references to the stm device and its module for the
duration of the character device's existence or the stm_source link.
Dropping these references is not well balanced everywhere, which may
lead to leaks.
This patch balances the acquisition and releasing of these two
references and annotates each site so that it's easier to verify
correctness by reading the code.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It is possible to concurrently assign the same output (a character
device writer or an stm_source device) to different stm devices,
which sets off a strategically placed warning in stm_output_assign().
To avoid this, use a spinlock to serialize (un)assignments between
outputs and stm devices.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If an illegal attempt is made to unlink stm source device from an
stm device, the stm device's link spinlock mistakenly remains locked.
While this really shouldn't happen (there's a warning in place), the
locking should remain in order so that we can still recover from this
situation if it indeed does happen.
This patch unifies the unlocking in the exit path of
__stm_source_link_drop() to fix this.
Reported-by: Laurent Fert <laurent.fert@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
STM drivers provide a callback to generate/send individual STP packets;
it also tells the stm core how many bytes of payload it has consumed.
However, we would also need to use the negative space of this return
value to communicate errors that occur during the packet generation,
in which case the stm core will have to take appropriate action.
For now, we need to account for the possibility that the stm driver may
not support certain combinations of packet type/flags, in which case
it is expected to signal an error.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The device unregister path uses wrong master index range when it tries
to free the allocated masters, it should, as does the rest of the stm
class code, use real master IDs.
This patch fixes the device unregister path to use real master IDs to
avoid memory leaks after unloading the stm driver.
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
[alexander.shishkin@intel.com: re-wrote the commit message]
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The return type "unsigned int" was used by the stm_find_master_chan function
despite of the aspect that it will eventually return a negative error code.
Done with the help of Coccinelle.
Signed-off-by: Lucas Tanure <tanure@linux.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, the character device write method allocates a temporary buffer
for user's data, but the user's data size is not sanitized and can cause
arbitrarily large allocations via kzalloc() or an integer overflow that
will then result in overwriting kernel memory.
This patch trims the input buffer size to avoid these issues.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since both sw_start and sw_end are master indices, the size of array
that holds them is sw_end - sw_start + 1, which the current code gets
wrong, allocating one item less than required.
This patch corrects the allocation size, avoiding potential slab
corruption.
Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
[alexander.shishkin@linux.intel.com: re-wrote the commit message]
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, the list of stm_sources linked to an stm device is protected by
a spinlock, which also means that sources' .unlink() method is called under
this spinlock. However, this method may (and does) sleep, which means
trouble.
This patch slightly reworks locking around stm::link_list so that bits that
might_sleep() are called with a mutex held instead. Modification of this
list requires both mutex and spinlock to be held, while looking at the list
can be done under either mutex or spinlock.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Source device's link is protected with srcu, mark it as such to have
proper build-time validation of accesses to this field. The update
side that's dereferencing it under an update lock also needs an
accessor to dereference this field to keep sparse happy.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A System Trace Module (STM) is a device exporting data in System Trace
Protocol (STP) format as defined by MIPI STP standards. Examples of such
devices are Intel(R) Trace Hub and Coresight STM.
This abstraction provides a unified interface for software trace sources
to send their data over an STM device to a debug host. In order to do
that, such a trace source needs to be assigned a pair of master/channel
identifiers that all the data from this source will be tagged with. The
STP decoder on the debug host side will use these master/channel tags to
distinguish different trace streams from one another inside one STP
stream.
This abstraction provides a configfs-based policy management mechanism
for dynamic allocation of these master/channel pairs based on trace
source-supplied string identifier. It has the flexibility of being
defined at runtime and at the same time (provided that the policy
definition is aligned with the decoding end) consistency.
For userspace trace sources, this abstraction provides write()-based and
mmap()-based (if the underlying stm device allows this) output mechanism.
For kernel-side trace sources, we provide "stm_source" device class that
can be connected to an stm device at run time.
Cc: linux-api@vger.kernel.org
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alexander Shishkin