Nothing sets function_trace_stop to disable function tracing anymore.
Remove the check for it in the arch code.

Link: http://lkml.kernel.org/r/53B08317.7010501@gmx.de

Cc: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Nothing sets function_trace_stop to disable function tracing anymore.
Remove the check for it in the arch code.

[ Please test this on your arch ]

Cc: Matt Fleming <matt@console-pimps.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Nothing sets function_trace_stop to disable function tracing anymore.
Remove the check for it in the arch code.

Link: http://lkml.kernel.org/r/20140703.211820.1674895115102216877.davem@davemloft.net

Cc: David S. Miller <davem@davemloft.net>
OKed-to-go-through-tracing-tree-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Nothing sets function_trace_stop to disable function tracing anymore.
Remove the check for it in the arch code.

Cc: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Zhigang Lu<zlu@tilera.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Nothing sets function_trace_stop to disable function tracing anymore.
Remove the check for it in the arch code.

Link: http://lkml.kernel.org/r/53C54D32.6000000@zytor.comAcked-by: H. Peter Anvin <hpa@linux.intel.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

function_trace_stop is no longer used to disable function tracing.
This means that archs are no longer limited if it does not support
checking this variable in the mcount trampoline.

No need to use the list_func for archs that do not support this
obsolete method.
Acked-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

function_trace_stop is no longer used to stop function tracing.
Remove the check from __ftrace_ops_list_func().

Also, call FTRACE_WARN_ON() instead of setting function_trace_stop
if a ops has no func to call.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

When function tracing is being updated function_trace_stop is set to
keep from tracing the updates. This was fine when function tracing
was done from stop machine. But it is no longer done that way and
this can cause real tracing to be missed.

Remove it.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

There are no more kernel users of ftrace_stop() and ftrace_start().
Remove them.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

All archs now use ftrace_graph_is_dead() to stop function graph
tracing. Remove the usage of ftrace_stop() as that is no longer
needed.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing. To do this, the arch code
must call ftrace_graph_is_dead() before it implements function graph.

Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing. To do this, the arch code
must call ftrace_graph_is_dead() before it implements function graph.

Cc: Anton Blanchard <anton@samba.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing. To do this, the arch code
must call ftrace_graph_is_dead() before it implements function graph.

Link: http://lkml.kernel.org/r/53B08317.7010501@gmx.de

Cc: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing. To do this, the arch code
must call ftrace_graph_is_dead() before it implements function graph.

Cc: Ralf Baechle <ralf@linux-mips.org>
Tested-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing. To do this, the arch code
must call ftrace_graph_is_dead() before it implements function graph.

Link: http://lkml.kernel.org/r/53C8D874.9090601@monstr.euTested-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing. To do this, the arch code
must call ftrace_graph_is_dead() before it implements function graph.

Link: http://lkml.kernel.org/r/53C54D18.3020602@zytor.comAcked-by: H. Peter Anvin <hpa@linux.intel.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() is going away as it disables parts of function tracing
that affects users that should not be affected. But ftrace_graph_stop()
is built on ftrace_stop(). Here's another example of killing all of
function tracing because something went wrong with function graph
tracing.

Instead of disabling all users of function tracing on function graph
error, disable only function graph tracing.

A new function is created called ftrace_graph_is_dead(). This is called
in strategic paths to prevent function graph from doing more harm and
allowing at least a warning to be printed before the system crashes.

NOTE: ftrace_stop() is still used until all the archs are converted over
to use ftrace_graph_is_dead(). After that, ftrace_stop() will be removed.
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() and ftrace_start() were added to the suspend and hibernate
process because there was some function within the work flow that caused
the system to reboot if it was traced. This function has recently been
found (restore_processor_state()). Now there's no reason to disable
function tracing while we are going into suspend or hibernate, which means
that being able to trace this will help tremendously in debugging any
issues with suspend or hibernate.

This also means that the ftrace_stop/start() functions can be removed
and simplify the function tracing code a bit.

Link: http://lkml.kernel.org/r/1518201.VD9cU33jRU@vostro.rjw.lanAcked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

ftrace_stop() is used to stop function tracing during suspend and resume
which removes a lot of possible debugging opportunities with tracing.
The reason was that some function in the resume path was causing a triple
fault if it were to be traced. The issue I found was that doing something
as simple as calling smp_processor_id() would reboot the box!

When function tracing was first created I didn't have a good way to figure
out what function was having issues, or it looked to be multiple ones. To
fix it, we just created a big hammer approach to the problem which was to
add a flag in the mcount trampoline that could be checked and not call
the traced functions.

Lately I developed better ways to find problem functions and I can bisect
down to see what function is causing the issue. I removed the flag that
stopped tracing and proceeded to find the problem function and it ended
up being restore_processor_state(). This function makes sense as when the
CPU comes back online from a suspend it calls this function to set up
registers, amongst them the GS register, which stores things such as
what CPU the processor is (if you call smp_processor_id() without this
set up properly, it would fault).

By making restore_processor_state() notrace, the system can suspend and
resume without the need of the big hammer tracing to stop.

Link: http://lkml.kernel.org/r/3577662.BSnUZfboWb@vostro.rjw.lanAcked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The function graph trampoline is called from the function trampoline
and both do a save and restore of registers. The save of registers
done by the function trampoline when only the function graph tracer
is running is a waste of CPU cycles.

As the function graph tracer trampoline in x86 is dependent from
the function trampoline, we can call it directly when a function
is only being traced by the function graph trampoline.
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Currently if an arch supports function graph tracing, the core code will
just assign the function graph trampoline to the function graph addr that
gets called.

But as the old method for function graph tracing always calls the function
trampoline first and that calls the function graph trampoline, some
archs may have the function graph trampoline dependent on operations that
were done in the function trampoline. This causes function graph tracer
to break on those archs.

Instead of having the default be to set the function graph ftrace_ops
to the function graph trampoline, have it instead just set it to zero
which will keep it from jumping to a trampoline that is not set up
to be jumped directly too.

Link: http://lkml.kernel.org/r/53BED155.9040607@nvidia.comReported-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
Tested-by: Tuomas Tynkkynen <ttynkkynen@nvidia.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Needed 099ed151 "tracing: Remove ftrace_stop/start() from
 reading the trace file" for the removal of ftrace_start/stop().

Disabling reading and writing to the trace file should not be able to
disable all function tracing callbacks. There's other users today
(like kprobes and perf). Reading a trace file should not stop those
from happening.

Cc: stable@vger.kernel.org # 3.0+
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

It was missing the description of set_graph_notrace file.  Add it.

Link: http://lkml.kernel.org/p/1402590233-22321-5-git-send-email-namhyung@kernel.orgSigned-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

When there's no entry in set_ftrace_notrace, it'll print nothing, but
it's better to print something like below like set_graph_notrace does:

  #### no functions disabled ####

Link: http://lkml.kernel.org/p/1402644246-4649-1-git-send-email-namhyung@kernel.orgReported-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

When there's no entry in set_graph_notrace, it'll print below message

  #### all functions enabled ####

While this is technically correct, it's better to print like below:

  #### no functions disabled ####

Link: http://lkml.kernel.org/p/1402590233-22321-3-git-send-email-namhyung@kernel.orgReported-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The ftrace_graph_notrace option is for specifying notrace filter for
function graph tracer at boot time.  It can be altered after boot
using set_graph_notrace file on the debugfs.

Link: http://lkml.kernel.org/p/1402590233-22321-2-git-send-email-namhyung@kernel.orgSigned-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Convert pr_warning to standard pr_warn
Define pr_fmt(fmt) fmt to avoid any future default fmt definition

Link: http://lkml.kernel.org/p/1402141388-21144-1-git-send-email-fabf@skynet.beSigned-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

When a filter file is open for writing and O_TRUNC is set, there's no
need to copy and free the filter entries.

Link: http://lkml.kernel.org/p/1402474014-28655-2-git-send-email-namhyung@kernel.orgSigned-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

As struct ftrace_page is managed in a single linked list, it should
free from the start page.

Link: http://lkml.kernel.org/p/1402474014-28655-1-git-send-email-namhyung@kernel.orgSigned-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

It seems like it's a leftover from commit 4104d326 ("ftrace:
Remove global function list and call function directly").  As it
isn't updated at all, checking its value is meaningless.

Let's get rid of it.

Link: http://lkml.kernel.org/p/1402584972-17824-1-git-send-email-namhyung@kernel.orgSigned-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

There's several locations in the kernel that open code the calculation
of the next location in the trace_seq buffer. This is usually done with

  p->buffer + p->len

Instead of having this open coded, supply a helper function in the
header to do it for them. This function is called trace_seq_buffer_ptr().

Link: http://lkml.kernel.org/p/20140626220129.452783019@goodmis.orgAcked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

This fixes checkpatch warning:

"WARNING: debugfs_remove(NULL) is safe this check is probably not required"
Link: http://lkml.kernel.org/p/1403802871-8599-1-git-send-email-fabf@skynet.beSigned-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

trace_seq_reserve() has no users in the kernel, it just wastes space.
Remove it.

Cc: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Currently trace_seq_putmem_hex() can only take as a parameter a pointer
to something that is 8 bytes or less, otherwise it will overflow the
buffer. This is protected by a macro that encompasses the call to
trace_seq_putmem_hex() that has a BUILD_BUG_ON() for the variable before
it is passed in. This is not very robust and if trace_seq_putmem_hex() ever
gets used outside that macro it will cause issues.

Instead of only being able to produce a hex output of memory that is for
a single word, change it to be more robust and allow any size input.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

For using trace_seq_*() functions in NMI context, I posted a patch to move
it to the lib/ directory. This caused Andrew Morton to take a look at the code.
He went through and gave a lot of comments about missing kernel doc,
inconsistent types for the save variable, mix match of EXPORT_SYMBOL_GPL()
and EXPORT_SYMBOL() as well as missing EXPORT_SYMBOL*()s. There were
a few comments about the way variables were being compared (int vs uint).

All these were good review comments and should be implemented regardless of
if trace_seq.c should be moved to lib/ or not.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The trace_seq_*() functions are a nice utility that allows users to manipulate
buffers with printf() like formats. It has its own trace_seq.h header in
include/linux and should be in its own file. Being tied with trace_output.c
is rather awkward.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Simplify ftrace_hash_disable/enable path in ftrace_hash_move
for hardening the process if the memory allocation failed.

Link: http://lkml.kernel.org/p/20140617110442.15167.81076.stgit@kbuild-fedora.novalocalSigned-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Strings should be copied with strlcpy instead of strncpy when they will
later be printed via %s. This guarantees that they terminate with a
NUL '\0' character and do not run pass the end of the allocated string.

This is only for sample code, but it should stil represent a good
role model.

Link: http://lkml.kernel.org/p/51C2E204.1080501@huawei.comSigned-off-by: Zhao Hongjiang <zhaohongjiang@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

The enabled_functions is used to help debug the dynamic function tracing.
Adding what trampolines are attached to files is useful for debugging.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>