linux.git/arch/sh/kernel/ftrace.c, branch v4.12.4

Merge tag 'trace-v4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

2016-10-06T18:48:41+00:00

Pull tracing updates from Steven Rostedt:
 "This release cycle is rather small.  Just a few fixes to tracing.

  The big change is the addition of the hwlat tracer. It not only
  detects SMIs, but also other latency that's caused by the hardware. I
  have detected some latency from large boxes having bus contention"

* tag 'trace-v4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Call traceoff trigger after event is recorded
  ftrace/scripts: Add helper script to bisect function tracing problem functions
  tracing: Have max_latency be defined for HWLAT_TRACER as well
  tracing: Add NMI tracing in hwlat detector
  tracing: Have hwlat trace migrate across tracing_cpumask CPUs
  tracing: Add documentation for hwlat_detector tracer
  tracing: Added hardware latency tracer
  ftrace: Access ret_stack->subtime only in the function profiler
  function_graph: Handle TRACE_BPUTS in print_graph_comment
  tracing/uprobe: Drop isdigit() check in create_trace_uprobe

tracing: Add NMI tracing in hwlat detector

2016-09-02T16:47:55+00:00

As NMIs can also cause latency when interrupts are disabled, the hwlat
detectory has no way to know if the latency it detects is from an NMI or an
SMI or some other hardware glitch.

As ftrace_nmi_enter/exit() funtions are no longer used (except for sh, which
isn't supported anymore), I converted those to "arch_ftrace_nmi_enter/exit"
and use ftrace_nmi_enter/exit() to check if hwlat detector is tracing or
not, and if so, it calls into the hwlat utility.

Since the hwlat detector only has a single kthread that is spinning with
interrupts disabled, it marks what CPU it is on, and if the NMI callback
happens on that CPU, it records the time spent in that NMI. This is added to
the output that is generated by the hwlat detector as:

 #3     inner/outer(us):    9/9     ts:1470836488.206734548
 #4     inner/outer(us):    0/8     ts:1470836497.140808588
 #5     inner/outer(us):    0/6     ts:1470836499.140825168 nmi-total:5 nmi-count:1
 #6     inner/outer(us):    9/9     ts:1470836501.140841748

All time is still tracked in microseconds.

The NMI information is only shown when an NMI occurred during the sample.

Signed-off-by: Steven Rostedt

ftrace: Add return address pointer to ftrace_ret_stack

2016-08-24T10:15:14+00:00

Storing this value will help prevent unwinders from getting out of sync
with the function graph tracer ret_stack.  Now instead of needing a
stateful iterator, they can compare the return address pointer to find
the right ret_stack entry.

Note that an array of 50 ftrace_ret_stack structs is allocated for every
task.  So when an arch implements this, it will add either 200 or 400
bytes of memory usage per task (depending on whether it's a 32-bit or
64-bit platform).

Signed-off-by: Josh Poimboeuf 
Acked-by: Steven Rostedt 
Cc: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Byungchul Park 
Cc: Denys Vlasenko 
Cc: Frederic Weisbecker 
Cc: H. Peter Anvin 
Cc: Kees Cook 
Cc: Linus Torvalds 
Cc: Nilay Vaish 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/a95cfcc39e8f26b89a430c56926af0bb217bc0a1.1471607358.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar

sh: ftrace: Fix the comments for ftrace_modify_code()

2015-12-23T19:27:24+00:00

There is no need to worry about module and __init text disappearing
case, because that ftrace has a module notifier that is called when
a module is being unloaded and before the text goes away and this
code grabs the ftrace_lock mutex and removes the module functions
from the ftrace list, such that it will no longer do any
modifications to that module's text, the update to make functions
be traced or not is done under the ftrace_lock mutex as well.
And by now, __init section codes should not been modified
by ftrace, because it is black listed in recordmcount.c and
ignored by ftrace.

Link: http://lkml.kernel.org/r/1449367378-29430-5-git-send-email-huawei.libin@huawei.com

Cc: linux-sh@vger.kernel.org
Suggested-by: Steven Rostedt 
Signed-off-by: Li Bin 
Signed-off-by: Steven Rostedt

sh: ftrace: Add call to ftrace_graph_is_dead() in function graph code

2014-07-18T17:56:57+00:00

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 
Signed-off-by: Steven Rostedt

ftrace: Do not pass data to ftrace_dyn_arch_init

2014-03-07T15:06:14+00:00

As the data parameter is not really used by any ftrace_dyn_arch_init,
remove that from ftrace_dyn_arch_init. This also removes the addr
local variable from ftrace_init which is now unused.

Note the documentation was imprecise as it did not suggest to set
(*data) to 0.

Link: http://lkml.kernel.org/r/1393268401-24379-4-git-send-email-jslaby@suse.cz

Cc: Frederic Weisbecker 
Cc: Ingo Molnar 
Cc: linux-arch@vger.kernel.org
Signed-off-by: Jiri Slaby 
Signed-off-by: Steven Rostedt

ftrace: Pass retval through return in ftrace_dyn_arch_init()

2014-03-07T15:06:13+00:00

No architecture uses the "data" parameter in ftrace_dyn_arch_init() in any
way, it just sets the value to 0. And this is used as a return value
in the caller -- ftrace_init, which just checks the retval against
zero.

Note there is also "return 0" in every ftrace_dyn_arch_init.  So it is
enough to check the retval and remove all the indirect sets of data on
all archs.

Link: http://lkml.kernel.org/r/1393268401-24379-3-git-send-email-jslaby@suse.cz

Cc: linux-arch@vger.kernel.org
Signed-off-by: Jiri Slaby 
Signed-off-by: Steven Rostedt

tracing: Unify arch_syscall_addr() implementations

2010-02-17T12:07:21+00:00

Most implementations of arch_syscall_addr() are the same, so create a
default version in common code and move the one piece that differs (the
syscall table) to asm/syscall.h.  New arch ports don't have to waste
time copying & pasting this simple function.

The s390/sparc versions need to be different, so document why.

Signed-off-by: Mike Frysinger 
Acked-by: David S. Miller 
Acked-by: Paul Mundt 
Acked-by: Heiko Carstens 
Cc: Steven Rostedt 
LKML-Reference: <1264498803-17278-1-git-send-email-vapier@gentoo.org>
Signed-off-by: Frederic Weisbecker

sh: ftrace: Fix up syscall tracing build.

2009-12-11T06:25:41+00:00

Syscall tracing metadata was shuffled around, update accordingly.

Signed-off-by: Paul Mundt

sh: ftrace: Make code modification NMI safe.

2009-10-13T07:52:50+00:00

This cribs the x86 implementation of ftrace_nmi_enter() and friends to
make ftrace_modify_code() NMI safe, particularly on SMP configurations.

For additional notes on the problems involved, see the comment below
ftrace_call_replace().

Signed-off-by: Paul Mundt