BPF programs, attached to kprobes, provide a safe way to execute
user-defined BPF byte-code programs without being able to crash or
hang the kernel in any way. The BPF engine makes sure that such
programs have a finite execution time and that they cannot break
out of their sandbox.

The user interface is to attach to a kprobe via the perf syscall:

	struct perf_event_attr attr = {
		.type	= PERF_TYPE_TRACEPOINT,
		.config	= event_id,
		...
	};

	event_fd = perf_event_open(&attr,...);
	ioctl(event_fd, PERF_EVENT_IOC_SET_BPF, prog_fd);

'prog_fd' is a file descriptor associated with BPF program
previously loaded.

'event_id' is an ID of the kprobe created.

Closing 'event_fd':

	close(event_fd);

... automatically detaches BPF program from it.

BPF programs can call in-kernel helper functions to:

  - lookup/update/delete elements in maps

  - probe_read - wraper of probe_kernel_read() used to access any
    kernel data structures

BPF programs receive 'struct pt_regs *' as an input ('struct pt_regs' is
architecture dependent) and return 0 to ignore the event and 1 to store
kprobe event into the ring buffer.

Note, kprobes are a fundamentally _not_ a stable kernel ABI,
so BPF programs attached to kprobes must be recompiled for
every kernel version and user must supply correct LINUX_VERSION_CODE
in attr.kern_version during bpf_prog_load() call.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Reviewed-by: NSteven Rostedt <rostedt@goodmis.org>
Reviewed-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1427312966-8434-4-git-send-email-ast@plumgrid.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

add TRACE_EVENT_FL_KPROBE flag to differentiate kprobe type of
tracepoints, since bpf programs can only be attached to kprobe
type of PERF_TYPE_TRACEPOINT perf events.
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Reviewed-by: NSteven Rostedt <rostedt@goodmis.org>
Reviewed-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1427312966-8434-3-git-send-email-ast@plumgrid.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Socket filter code and other subsystems with upcoming eBPF
support should not need to deal with the fact that we have
CONFIG_BPF_SYSCALL defined or not.

Having the bpf syscall as a config option is a nice thing and
I'd expect it to stay that way for expert users (I presume one
day the default setting of it might change, though), but code
making use of it should not care if it's actually enabled or
not.

Instead, hide this via header files and let the rest deal with it.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NAlexei Starovoitov <ast@plumgrid.com>
Reviewed-by: NMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1427312966-8434-2-git-send-email-ast@plumgrid.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

This WIP branch is now ready to be merged.
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

 - Fix 'perf script' pipe mode segfault, by always initializing ordered_events in
   perf_session__new(). (Arnaldo Carvalho de Melo)

 - Fix ppid for synthesized fork events. (David Ahern)

 - Fix kernel symbol resolution of callchains in S/390 by remembering the
   cpumode. (David Hildenbrand)

Infrastructure changes:

 - Disable libbabeltrace check by default in the build system. (Jiri Olsa)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

As these can be obtained from the ordered_events pointer, via
container_of, reducing the cross section of ordered_samples.

These were added to ordered_samples in:

 commit b7b61cbe
 Author: Arnaldo Carvalho de Melo <acme@redhat.com>
 Date:   Tue Mar 3 11:58:45 2015 -0300

    perf ordered_events: Shorten function signatures

    By keeping pointers to machines, evlist and tool in ordered_events.

But that was more a transitional patch while moving stuff out from
perf_session.c to ordered_events.c and possibly not even needed by then,
as we could use the container_of() method and instead of having the
nr_unordered_samples stats in events_stats, we can have it in
ordered_samples.
Based-on-a-patch-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-4lk0t9js82g0tfc0x1onpkjt@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Even when it is not used to actually reorder events, some of its fields
are used, like session->ordered_events->tool, to shorten function
signatures where tool, for instance, was being passed, as the tool is
needed for the ordered_events code, we need it there and might as well
use it for other perf_session needs.

This fixes a problem where 'perf script' had some condition that made
session->ordered_events not to be initialized even with its
script->tool ordered_events related flags asking for it to be, which
looks like another bug and needs to be investigated further.

Always initializing session->ordered_events at least leaves the current
assumptions in place, so do it now.
Reported-by: NDavid Ahern <dsahern@gmail.com>
Reviewed-by: NDavid Ahern <dsahern@gmail.com>
Tested-by: NDavid Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-b1xxk0rwkz2a0gip1uufmjqg@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

363b785f added synthesized fork events and set a thread's parent id to
itself. Since we are already processing /proc/<pid>/status the ppid can
be determined properly. Make it so.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NDon Zickus <dzickus@redhat.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Joe Mario <jmario@redhat.com>
Link: http://lkml.kernel.org/r/1427747758-18510-2-git-send-email-dsahern@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Rather than parsing /proc/pid/status file one line at a time, read it
into a buffer in one shot and search for all strings in one pass.

tgid conversion also simplified -- removing the isspace walk. As noted
by Arnaldo those are not needed for atoi == strtol calls.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Acked-by: NDon Zickus <dzickus@redhat.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Joe Mario <jmario@redhat.com>
Link: http://lkml.kernel.org/r/1427747758-18510-1-git-send-email-dsahern@gmail.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Commit 2e77784b ("perf callchain: Move cpumode resolve code to
add_callchain_ip") promised "No change in behavior.".

As this commit breaks callchains on s390x (symbols not getting resolved,
observed when profiling the kernel), this statement is wrong. The cpumode
must be kept when iterating over all ips, otherwise the default
(PERF_RECORD_MISC_USER) will be used by error.
Signed-off-by: NDavid Hildenbrand <dahi@linux.vnet.ibm.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1427703060-59883-1-git-send-email-dahi@linux.vnet.ibm.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

Disabling libbabeltrace check by default and replacing the
NO_LIBBABELTRACE make variable with LIBBABELTRACE.

Users wanting the libbabeltrace feature need to build via:

  $ make LIBBABELTRACE=1

The reason for this is that the libababeltrace interface we use (version
1.3) hasn't been packaged/released yet, thus the failing feature check
only slows down build and confuses other (non CTF) developers.
Requested-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Acked-by: NIngo Molnar <mingo@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jeremie Galarneau <jgalar@efficios.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20150328103030.GA8431@krava.redhat.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

While thinking on the whole clock discussion it occurred to me we have
two distinct uses of time:

 1) the tracking of event/ctx/cgroup enabled/running/stopped times
    which includes the self-monitoring support in struct
    perf_event_mmap_page.

 2) the actual timestamps visible in the data records.

And we've been conflating them.

The first is all about tracking time deltas, nobody should really care
in what time base that happens, its all relative information, as long
as its internally consistent it works.

The second however is what people are worried about when having to
merge their data with external sources. And here we have the
discussion on MONOTONIC vs MONOTONIC_RAW etc..

Where MONOTONIC is good for correlating between machines (static
offset), MONOTNIC_RAW is required for correlating against a fixed rate
hardware clock.

This means configurability; now 1) makes that hard because it needs to
be internally consistent across groups of unrelated events; which is
why we had to have a global perf_clock().

However, for 2) it doesn't really matter, perf itself doesn't care
what it writes into the buffer.

The below patch makes the distinction between these two cases by
adding perf_event_clock() which is used for the second case. It
further makes this configurable on a per-event basis, but adds a few
sanity checks such that we cannot combine events with different clocks
in confusing ways.

And since we then have per-event configurability we might as well
retain the 'legacy' behaviour as a default.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

An upcoming patch will depend on tai_ns() and NMI-safe ktime_get_raw_fast(),
so merge timers/core here in a separate topic branch until it's all cooked
and timers/core is merged upstream.
Signed-off-by: NIngo Molnar <mingo@kernel.org>

While looking at some fuzzer output I noticed that we do not hold any
locks on leader->ctx and therefore the sibling_list iteration is
unsafe.

Acquire the relevant ctx->mutex before calling into the pmu specific
code.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Link: http://lkml.kernel.org/r/20150225151639.GL5029@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>

perf_pmu_disable() is called before pmu->add() and perf_pmu_enable() is called
afterwards. No need to call these inside of x86_pmu_add() as well.
Signed-off-by: NDavid Ahern <dsahern@gmail.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1424281543-67335-1-git-send-email-dsahern@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NIngo Molnar <mingo@kernel.org>

Because it was the only clock for which we didn't have a _ns()
accessor yet.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Add the NMI safe CLOCK_MONOTONIC_RAW accessor..
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NJohn Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.562746929@infradead.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

In preparation for more tk_fast instances, remove all hard-coded
tk_fast_mono references.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NJohn Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.484279927@infradead.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Introduce tkr_raw and make use of it.

  base_raw -> tkr_raw.base
  clock->{mult,shift} -> tkr_raw.{mult.shift}

Kill timekeeping_get_ns_raw() in favour of
timekeeping_get_ns(&tkr_raw), this removes all mono_raw special
casing.

Duplicate the updates to tkr_mono.cycle_last into tkr_raw.cycle_last,
both need the same value.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NJohn Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.422589590@infradead.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

In preparation of adding another tkr field, rename this one to
tkr_mono. Also rename tk_read_base::base_mono to tk_read_base::base,
since the structure is not specific to CLOCK_MONOTONIC and the mono
name got added to the tk_read_base instance.

Lots of trivial churn.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: NJohn Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20150319093400.344679419@infradead.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

On Broadwell INST_RETIRED.ALL cannot be used with any period
that doesn't have the lowest 6 bits cleared. And the period
should not be smaller than 128.

This is erratum BDM11 and BDM55:

  http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/5th-gen-core-family-spec-update.pdf

BDM11: When using a period < 100; we may get incorrect PEBS/PMI
interrupts and/or an invalid counter state.
BDM55: When bit0-5 of the period are !0 we may get redundant PEBS
records on overflow.

Add a new callback to enforce this, and set it for Broadwell.

How does this handle the case when an app requests a specific
period with some of the bottom bits set?

Short answer:

Any useful instruction sampling period needs to be 4-6 orders
of magnitude larger than 128, as an PMI every 128 instructions
would instantly overwhelm the system and be throttled.
So the +-64 error from this is really small compared to the
period, much smaller than normal system jitter.

Long answer (by Peterz):

IFF we guarantee perf_event_attr::sample_period >= 128.

Suppose we start out with sample_period=192; then we'll set period_left
to 192, we'll end up with left = 128 (we truncate the lower bits). We
get an interrupt, find that period_left = 64 (>0 so we return 0 and
don't get an overflow handler), up that to 128. Then we trigger again,
at n=256. Then we find period_left = -64 (<=0 so we return 1 and do get
an overflow). We increment with sample_period so we get left = 128. We
fire again, at n=384, period_left = 0 (<=0 so we return 1 and get an
overflow). And on and on.

So while the individual interrupts are 'wrong' we get then with
interval=256,128 in exactly the right ratio to average out at 192. And
this works for everything >=128.

So the num_samples*fixed_period thing is still entirely correct +- 127,
which is good enough I'd say, as you already have that error anyhow.

So no need to 'fix' the tools, al we need to do is refuse to create
INST_RETIRED:ALL events with sample_period < 128.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
[ Updated comments and changelog a bit. ]
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1424225886-18652-3-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Add Broadwell support for Broadwell to perf.

The basic support is very similar to Haswell. We use the new cache
event list added for Haswell earlier. The only differences
are a few bits related to remote nodes. To avoid an extra,
mostly identical, table these are patched up in the initialization code.

The constraint list has one new event that needs to be handled over Haswell.

Includes code and testing from Kan Liang.
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1424225886-18652-2-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Haswell offcore events are quite different from Sandy Bridge.
Add a new table to handle Haswell properly.

Note that the offcore bits listed in the SDM are not quite correct
(this is currently being fixed). An uptodate list of bits is
in the patch.

The basic setup is similar to Sandy Bridge. The prefetch columns
have been removed, as prefetch counting is not very reliable
on Haswell. One L1 event that is not in the event list anymore
has been also removed.

- data reads do not include code reads (comparable to earlier Sandy Bridge tables)
- data counts include speculative execution (except L1 write, dtlb, bpu)
- remote node access includes both remote memory, remote cache, remote mmio.
- prefetches are not included in the counts for consistency
  (different from Sandy Bridge, which includes prefetches in the remote node)
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
[ Removed the HSM30 comments; we don't have them for SNB/IVB either. ]
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1424225886-18652-1-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo:

User visible changes:

  - Show the first event with an invalid filter (David Ahern, Arnaldo Carvalho de Melo)

  - Fix garbage output when intermixing syscalls from different threads in 'perf trace' (Arnaldo Carvalho de Melo)

  - Fix 'perf timechart' SIBGUS error on sparc64 (David Ahern)

Infrastructure changes:

  - Set JOBS based on CPU or processor, making it work on SPARC, where
    /proc/cpuinfo has "CPU", not "processor" (David Ahern)

  - Zero should not be considered "not found" in libtraceevent's eval_flag() (Steven Rostedt)
Signed-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Trivial cleanups, to improve the readability of the generic sched_clock() code:

 - Improve and standardize comments
 - Standardize the coding style
 - Use vertical spacing where appropriate
 - etc.

No code changed:

  md5:
    19a053b31e0c54feaeff1492012b019a  sched_clock.o.before.asm
    19a053b31e0c54feaeff1492012b019a  sched_clock.o.after.asm

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Currently it is possible for an NMI (or FIQ on ARM) to come in
and read sched_clock() whilst update_sched_clock() has locked
the seqcount for writing. This results in the NMI handler
locking up when it calls raw_read_seqcount_begin().

This patch fixes the NMI safety issues by providing banked clock
data. This is a similar approach to the one used in Thomas
Gleixner's 4396e058("timekeeping: Provide fast and NMI safe
access to CLOCK_MONOTONIC").
Suggested-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-6-git-send-email-john.stultz@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently update_sched_clock() is marked as notrace but this
function is not called by ftrace. This is trivially fixed by
removing the mark up.
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-5-git-send-email-john.stultz@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently cd.read_data.suspended is read by the hotpath function
sched_clock(). This variable need not be accessed on the
hotpath. In fact, once it is removed, we can remove the
conditional branches from sched_clock() and install a dummy
read_sched_clock function to suspend the clock.

The new master copy of the function pointer
(actual_read_sched_clock) is introduced and is used for all
reads of the clock hardware except those within sched_clock
itself.
Suggested-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-4-git-send-email-john.stultz@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently sched_clock(), a very hot code path, is not optimized
to minimise its cache profile. In particular:

  1. cd is not ____cacheline_aligned,

  2. struct clock_data does not distinguish between hotpath and
     coldpath data, reducing locality of reference in the hotpath,

  3. Some hotpath data is missing from struct clock_data and is marked
     __read_mostly (which more or less guarantees it will not share a
     cache line with cd).

This patch corrects these problems by extracting all hotpath
data into a separate structure and using ____cacheline_aligned
to ensure the hotpath uses a single (64 byte) cache line.
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-3-git-send-email-john.stultz@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Currently the scope of the raw_write_seqcount_begin/end() in
sched_clock_register() far exceeds the scope of the read section
in sched_clock(). This gives the impression of safety during
cursory review but achieves little.

Note that this is likely to be a latent issue at present because
sched_clock_register() is typically called before we enable
interrupts, however the issue does risk bugs being needlessly
introduced as the code evolves.

This patch fixes the problem by increasing the scope of the read
locking performed by sched_clock() to cover all data modified by
sched_clock_register.

We also improve clarity by moving writes to struct clock_data
that do not impact sched_clock() outside of the critical
section.
Signed-off-by: NDaniel Thompson <daniel.thompson@linaro.org>
[ Reworked it slightly to apply to tip/timers/core]
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1427397806-20889-2-git-send-email-john.stultz@linaro.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>

Pull drm refcounting fixes from Dave Airlie:
 "Here is the complete set of i915 bug/warn/refcounting fixes"

* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
  drm/i915: Fixup legacy plane->crtc link for initial fb config
  drm/i915: Fix atomic state when reusing the firmware fb
  drm/i915: Keep ring->active_list and ring->requests_list consistent
  drm/i915: Don't try to reference the fb in get_initial_plane_config()
  drm: Fixup racy refcounting in plane_force_disable

Pull device mapper fix from Mike Snitzer:
 "Fix DM core device cleanup regression -- due to a latent race that was
  exposed by the bdi changes that were introduced during the 4.0 merge"

* tag 'dm-4.0-fix-2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: fix add_disk() NULL pointer due to race with free_dev()

Merge tag 'linux-kselftest-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull kselftest fix from Shuah Khan.

* tag 'linux-kselftest-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests: Fix build failures when invoked from kselftest target

This should cover the final warnings in -rc5 with two more backports
from our development branch (drm-intel-next-queued). They're the ones
from Daniel and Damien, with references to the reports.

This is on top of drm-fixes because of the dependency on the two earlier
fixes not yet in Linus' tree.

There's an additional regression fix from Chris.

* tag 'drm-intel-fixes-2015-03-26' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Fixup legacy plane->crtc link for initial fb config
  drm/i915: Fix atomic state when reusing the firmware fb
  drm/i915: Keep ring->active_list and ring->requests_list consistent

Pull s390 fixes from Martin Schwidefsky:
 "A couple of bug fixes for s390.

  The ftrace comile fix is quite large for a -rc6 release, but it would
  be nice to have it in 4.0"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/smp: reenable smt after resume
  s390/mm: limit STACK_RND_MASK for compat tasks
  s390/ftrace: fix compile error if CONFIG_KPROBES is disabled
  s390/cpum_sf: add diagnostic sampling event only if it is authorized

Guilherme Cox found that:

 There is, however, a potential bug if there is an item with code zero
 that is not the first one in the symbol list, since eval_flag(..)
 returns 0 when it doesn't find anything.

That is, if you have the following enums:

enum {
  FOO_START = 0,
  FOO_GO    = 1,
  FOO_END   = 2
}

and then have:

  __print_symbolic(foo, FOO_GO, "go", FOO_START, "start",
		        FOO_END, "end")

If none of the enums are known to pevent, then eval_flag() will return
zero, and it will match it to the first item in the list, which would be
FOO_GO, which is not zero.

Luckily, in most cases, the first element would be zero, and the parsing
would match out of sheer luck.
Reported-by: NGuilherme Cox <cox@computer.org>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20150324145813.0bfe95ba@gandalf.local.homeSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

 commit e596663e
 Author: Arnaldo Carvalho de Melo <acme@redhat.com>
 Date:   Fri Feb 13 13:22:21 2015 -0300

    perf trace: Handle multiple threads better wrt syscalls being intermixed

Introduced a bug where it considered the number of bytes output directly
to the output file when formatting the syscall entry buffer that is
stored to be finally printed at syscall exit, ending up leaving garbage
at the start of syscalls that appeared while another syscall was being
processed, in another thread. Fix it.

Example of garbage in the output before this patch:

 4280.102 (  0.000 ms): lsmd/763  ... [continued]: select()) = 0 Timeout
 4280.107 (275.250 ms): tuned/852 select(tvp: 0x7f41f7ffde50        ) ...
 4280.109 (  0.002 ms): lsmd/763 Xl��                                ) = -10
 4639.197 (  0.000 ms): systemd-journa/542  ... [continued]: epoll_wait()) = 1
 4639.202 (359.088 ms): lsmd/763 select(n: 6, inp: 0x7ffff21daad0, tvp: 0x7ffff21daac0) ...
 4639.207 (  0.005 ms): systemd-journa/542 Hn��                      ) = 106
 4639.221 (  0.002 ms): systemd-journa/542 uname(name: 0x7ffdbaed8e00) = 0
 4639.271 (  0.008 ms): systemd-journa/542 ftruncate(fd: 11</run/log/journal/60cd52417cf440a4a80107518bbd3c20/system.journal>, length: 50331648) = 0

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-9ckfe8mvsedgkg6y80gz1ul8@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>