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A TSC packet can slip past MTC packets so that the timestamp appears to
go backwards. One estimate is that can be up to about 40 CPU cycles,
which is certainly less than 0x1000 TSC ticks, but accept slippage an
order of magnitude more to be on the safe side.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Fixes: 79b58424 ("perf tools: Add Intel PT support for decoding MTC packets")
Link: http://lkml.kernel.org/r/20190325135135.18348-1-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Data is copied when the trace is stopped, so packets are never split
between buffers except when processing if the buffer cannot fit in the
address space which can only happen on 32-bit systems. Change the logic
to reflect that.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190206103947.15750-5-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

CYC packet timestamp calculation depends upon CBR which was being
cleared upon overflow (OVF). That can cause errors due to failing to
synchronize with sideband events. Even if a CBR change has been lost,
the old CBR is still a better estimate than zero. So remove the clearing
of CBR.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20190206103947.15750-4-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Auxtrace records might have up to 7 bytes of padding appended. Adjust
the overlap accordingly.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20190206103947.15750-3-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

One cause of decoding errors is un-synchronized side-band data.
Timestamps are needed to debug such cases. TSC packet timestamps are
logged. Log also MTC and CYC timestamps.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/r/20181105073505.8129-3-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Have the Intel PT decoder implement the new Intel PT decoder flags for
trace begin / end.

Previously, the decoder would indicate begin / end by a branch from / to
zero. That hides useful information, in particular when a trace ends
with a call. That happens when using address filters, for example:

  $ perf record -e intel_pt/cyc,mtc_period=0,noretcomp/u --filter='filter main @ /bin/uname ' uname Linux
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.031 MB perf.data ]

Before:

  $ perf script --itrace=cre -Ftime,flags,ip,sym,symoff,addr --ns
   7249.622183310:   tr strt         0 [unknown] =>   401590 main+0x0
   7249.622183311:   call       4015b9 main+0x29 =>        0 [unknown]
   7249.622183711:   tr strt         0 [unknown] =>   4015be main+0x2e
   7249.622183714:   call       4015c8 main+0x38 =>        0 [unknown]
   7249.622247731:   tr strt         0 [unknown] =>   4015cd main+0x3d
   7249.622247760:   call       4015d7 main+0x47 =>        0 [unknown]
   7249.622248340:   tr strt         0 [unknown] =>   4015dc main+0x4c
   7249.622248341:   call       4015e1 main+0x51 =>        0 [unknown]
   7249.622248681:   tr strt         0 [unknown] =>   4015e6 main+0x56
   7249.622248682:   call       4015eb main+0x5b =>        0 [unknown]
   7249.622248970:   tr strt         0 [unknown] =>   4015f0 main+0x60
   7249.622248971:   call       401612 main+0x82 =>        0 [unknown]
   7249.622249757:   tr strt         0 [unknown] =>   401617 main+0x87
   7249.622249770:   call       401847 main+0x2b7 =>        0 [unknown]
   7249.622250606:   tr strt         0 [unknown] =>   40184c main+0x2bc
   7249.622250612:   call       4019bf main+0x42f =>        0 [unknown]
   7249.622256823:   tr strt         0 [unknown] =>   4019c4 main+0x434
   7249.622256863:   call       4019f5 main+0x465 =>        0 [unknown]
   7249.622264217:   tr strt         0 [unknown] =>   4019fa main+0x46a
   7249.622264235:   call       401832 main+0x2a2 =>        0 [unknown]

After:

  $ perf script --itrace=cre -Ftime,flags,ip,sym,symoff,addr --ns
   7249.622183310:   tr strt              0 [unknown] =>   401590 main+0x0
   7249.622183311:   tr end  call    4015b9 main+0x29 =>   401ef0 set_program_name+0x0
   7249.622183711:   tr strt              0 [unknown] =>   4015be main+0x2e
   7249.622183714:   tr end  call    4015c8 main+0x38 =>   4014b0 setlocale@plt+0x0
   7249.622247731:   tr strt              0 [unknown] =>   4015cd main+0x3d
   7249.622247760:   tr end  call    4015d7 main+0x47 =>   4012d0 bindtextdomain@plt+0x0
   7249.622248340:   tr strt              0 [unknown] =>   4015dc main+0x4c
   7249.622248341:   tr end  call    4015e1 main+0x51 =>   4012b0 textdomain@plt+0x0
   7249.622248681:   tr strt              0 [unknown] =>   4015e6 main+0x56
   7249.622248682:   tr end  call    4015eb main+0x5b =>   404340 atexit+0x0
   7249.622248970:   tr strt              0 [unknown] =>   4015f0 main+0x60
   7249.622248971:   tr end  call    401612 main+0x82 =>   401320 getopt_long@plt+0x0
   7249.622249757:   tr strt              0 [unknown] =>   401617 main+0x87
   7249.622249770:   tr end  call    401847 main+0x2b7 =>   401360 uname@plt+0x0
   7249.622250606:   tr strt              0 [unknown] =>   40184c main+0x2bc
   7249.622250612:   tr end  call    4019bf main+0x42f =>   401b10 print_element+0x0
   7249.622256823:   tr strt              0 [unknown] =>   4019c4 main+0x434
   7249.622256863:   tr end  call    4019f5 main+0x465 =>   401340 __overflow@plt+0x0
   7249.622264217:   tr strt              0 [unknown] =>   4019fa main+0x46a
   7249.622264235:   tr end  call    401832 main+0x2a2 =>   401520 exit@plt+0x0
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20180920130048.31432-7-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Some Atom CPUs can produce FUP packets that contain NLIP (next linear
instruction pointer) instead of CLIP (current linear instruction
pointer).  That will result in "Unexpected indirect branch" errors. Fix
by comparing IP to NLIP in that case.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1527762225-26024-5-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

On some platforms, overflows will clear before MTC wraparound, and there
is no following TSC/TMA packet. In that case the previous TMA is valid.
Since there will be a valid TMA either way, stop setting 'have_tma' to
false upon overflow.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1527762225-26024-4-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

It is possible to have a CBR packet between a FUP packet and
corresponding TIP packet. Stop treating it as an error.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1527762225-26024-3-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

timestamp_insn_cnt is used to estimate the timestamp based on the number of
instructions since the last known timestamp.

If the estimate is not accurate enough decoding might not be correctly
synchronized with side-band events causing more trace errors.

However there are always timestamps following an overflow, so the
estimate is not needed and can indeed result in more errors.

Suppress the estimate by setting timestamp_insn_cnt to zero.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1520431349-30689-5-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

When a TIP packet is expected but there is a different packet, it is an
error. However the unexpected packet might be something important like a
TSC packet, so after the error, it is necessary to continue from there,
rather than the next packet. That is achieved by setting pkt_step to
zero.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1520431349-30689-4-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Overlap detection was not not updating the buffer's 'consecutive' flag.
Marking buffers consecutive has the advantage that decoding begins from
the start of the buffer instead of the first PSB. Fix overlap detection
to identify consecutive buffers correctly.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1520431349-30689-2-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

CBR (core-to-bus ratio) packets provide an indication of CPU frequency. A
more accurate measure can be made by counting the cycles (given by CYC
packets) in between other timing packets (either MTC or TSC). Using TSC
packets has at least 2 issues: 1) timing might have stopped (e.g. mwait) or
2) TSC packets within PSB+ might slip past CYC packets. For now, simply do
not use TSC packets for calculating CPU cycles to TSC. That leaves the case
where 2 MTC packets are used, otherwise falling back to the CBR value.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-37-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Add decoder support for informing the tools of changes to the core-to-bus
ratio (CBR).
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-16-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Future proof CBR packet decoding by passing through also the undefined
'reserved' byte in the packet payload.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-15-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Add decoder support for PTWRITE, MWAIT, PWRE, PWRX and EXSTOP packets. This
patch only affects the decoder, so the tools still do not select or consume
the new information. That is added in subsequent patches.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-14-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The kernel now supports the disabling of branch tracing, however the
decoder assumes branch tracing is always enabled. Pass through a parameter
to indicate whether branch tracing is enabled and use it to avoid cases
when the decoder is expecting branch packets. There are 2 such cases.
First, FUP packets which can bind to an IP even when there is no branch
tracing. Secondly, the decoder will try to use branch packets to find an IP
to start decoding or to recover from errors.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-11-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf tools uses __fallthrough. Add missing  __fallthrough to a switch
statement.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1495786658-18063-10-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Sometimes a FUP packet is associated with a TSX transaction and a flag is
set to indicate that. Ensure that flag is cleared on any error condition
because at that point the decoder can no longer assume it is correct.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-9-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The decoder will try to use branch packets to find an IP to start decoding
or to recover from errors. Currently the FUP packet is used only in the
case of an overflow, however there is no reason for that to be a special
case. So just use FUP always when scanning for an IP.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-8-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Intel PT uses IP compression based on the last IP. For decoding purposes,
'last IP' is not updated when a branch target has been suppressed, which is
indicated by IPBytes == 0. IPBytes is stored in the packet 'count', so
ensure never to set 'last_ip' when packet 'count' is zero.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-7-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Intel PT uses IP compression based on the last IP. For decoding
purposes, 'last IP' is considered to be reset to zero whenever there is
a synchronization packet (PSB). The decoder wasn't doing that, and was
treating the zero value to mean that there was no last IP, whereas
compression can be done against the zero value. Fix by setting last_ip
to zero when a PSB is received and keep track of have_last_ip.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-6-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

A value of zero is used to indicate that there is no IP. Ensure the
value is zero when the state is INTEL_PT_STATE_NO_IP.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-5-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The return compression stack must be cleared whenever there is a PSB. Fix
one case where that was not happening.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-4-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The decoder uses its current timestamp in samples. Usually that is a
timestamp that has already passed, but in some cases it is a timestamp
for a branch that the decoder is walking towards, and consequently
hasn't reached. Improve that situation by using the pkt_state to
determine when to use the current or previous timestamp.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-3-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Move decoder error setting into one condition.

Cc'ed to stable because later fixes depend on it.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1495786658-18063-2-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To address new warnings emmited by gcc 7, e.g.::

    CC       /tmp/build/perf/util/intel-pt-decoder/intel-pt-pkt-decoder.o
    CC       /tmp/build/perf/tests/parse-events.o
  util/intel-pt-decoder/intel-pt-pkt-decoder.c: In function 'intel_pt_pkt_desc':
  util/intel-pt-decoder/intel-pt-pkt-decoder.c:499:6: error: this statement may fall through [-Werror=implicit-fallthrough=]
     if (!(packet->count))
        ^
  util/intel-pt-decoder/intel-pt-pkt-decoder.c:501:2: note: here
    case INTEL_PT_CYC:
    ^~~~
    CC       /tmp/build/perf/util/intel-pt-decoder/intel-pt-decoder.o
  cc1: all warnings being treated as errors
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-mf0hw789pu9x855us5l32c83@git.kernel.org

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Change Intel PT and BTS to pass up the length and the instruction
bytes of the decoded or sampled instruction in the perf sample.

The decoder already knows this information, we just need to pass it
up. Since it is only a couple of movs it is not very expensive.

Handle instruction cache too. Make sure ilen is always initialized.

Used in the next patch.

[Adrian: re-base on top (and adjust for) instruction buffer size tidy-up]
[Adrian: add BTS support and adjust commit message accordingly]
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Link: http://lkml.kernel.org/r/1475847747-30994-3-git-send-email-adrian.hunter@intel.com

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The MTC packet provides a 8-bit slice of CTC which is related to TSC by
the TMA packet, however the TMA packet only provides the lower 16 bits
of CTC.  If mtc_shift > 8 then some of the MTC bits are not in the CTC
provided by the TMA packet. Fix-up the last_mtc calculated from the TMA
packet by copying the missing bits from the current MTC assuming the
least difference between the two, and that the current MTC comes after
last_mtc.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v4.3+
Link: http://lkml.kernel.org/r/1475062896-22274-2-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

In cycle-accurate mode, timestamps can be calculated from CYC packets.
The decoder also estimates timestamps based on the number of
instructions since the last timestamp. For that to work in
cycle-accurate mode, the instruction count needs to be reset to zero
when a timestamp is calculated from a CYC packet, but that wasn't
happening, so fix it.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v4.3+
Link: http://lkml.kernel.org/r/1475062896-22274-1-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

When address filters are used, the decoder must detect the end of a
filter region (or a branch into a tracestop region) by matching Packet
Generation Disabled (TIP.PGD) packets against the object code using the
IP given in the packet. However, due to errata SKL014 "Intel PT TIP.PGD
May Not Have Target IP Payload", that IP may not be present.

Enable the decoder to handle that by adding a new callback function
'pgd_ip()' which indicates whether the IP is not traced, in which case
that is the point where the trace was disabled.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: http://lkml.kernel.org/r/1474641528-18776-16-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The June 2015 Intel SDM introduced IP Compression types 4 and 6. Refer
to section 36.4.2.2 Target IP (TIP) Packet - IP Compression.

Existing Intel PT packet decoder did not support type 4, and got type 6
wrong.  Because type 3 and type 4 have the same number of bytes, the
packet 'count' has been changed from being the number of ip bytes to
being the type code.  That allows the Intel PT decoder to correctly
decide whether to sign-extend or use the last ip.  However that also
meant the code had to be adjusted in a number of places.

Currently hardware is not using the new compression types, so this fix
has no effect on existing hardware.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1469005206-3049-1-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The check for the maximum code is off-by-one; the current comparison of
a code that is INTEL_PT_ERR_MAX will cause the strlcpy to perform an out
of bounds array access on the intel_pt_err_msgs array.

Fix this with a >= comparison.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1461524203-10224-1-git-send-email-colin.king@canonical.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

TSC packets contain only 7 bytes of TSC.  The 8th byte is assumed to
change so infrequently that its value can be inferred.  However the
logic must cater for a 7 byte wraparound, which it does by adding 1 to
the top byte.

The existing code was doing that with a while loop even though the
addition should only need to be done once.  That logic won't work (will
loop forever) if TSC wraps around at the 8th byte.  Theoretically that
would take at least 10 years, unless something else went wrong.

And what else could go wrong.  Well, if the chunks of trace data are
processed out of order, it will make it look like the 7-byte TSC has
gone backwards (i.e. wrapped).  If that happens 256 times then stuck in
the while loop it will be.

Fix that by getting rid of the unnecessary while loop.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1443186956-18718-4-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

A TRACESTOP packet is produced when an Intel PT trace enters a defined
region of the address space at which point the tracing stops.

This patch just adds decoder support.

Support for specifying TRACESTOP regions is left until later.

For details refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-25-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

CYC packets provide even finer grain timestamp information than MTC and
TSC packets.  A CYC packet contains the number of CPU cycles since the
last CYC packet.

This patch just adds decoder support.  The CPU frequency can be related
to TSC using the Maximum Non-Turbo Ratio in combination with the CBR
(core-to-bus ratio) packet.  However more accuracy is achieved by simply
interpolating the number of cycles between other timing packets like MTC
or TSC.  This patch takes the latter approach.

Support for a default value and validation of values is provided by a
later patch. Also documentation is updated in a separate patch.

For details refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-23-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

MTC packets provide finer grain timestamp information than TSC packets.
MTC packets record time using the hardware crystal clock (CTC) which is
related to TSC packets using a TMA packet.

This patch just adds decoder support.

Support for a default value and validation of values is provided by a
later patch. Also documentation is updated in a separate patch.

For details refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-21-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

New features have been added to Intel PT which include a number of new
packet definitions.

This patch adds packet definitions for new packets: TMA, MTC, CYC, VMCS,
TRACESTOP and MNT.  Also another bit in PIP is defined.

This patch only adds support for the definitions. Later patches add
support for decoding TMA, MTC, CYC and TRACESTOP which is where those
packets are explained.

VMCS and the newly defined bit in PIP are used with virtualization which
is not supported yet.  MNT is a maintenance packet which the decoder
should ignore.

For details, refer to the June 2015 or later Intel 64 and IA-32
Architectures SDM Chapter 36 Intel Processor Trace.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-19-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

The period on synthesized 'instructions' samples was being set to a
fixed value, whereas the correct value is the number of instructions
since the last sample, which is a value that the decoder can provide.
So do it that way.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-14-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Add support for decoding an Intel Processor Trace.

Intel PT trace data must be 'decoded' which involves walking the object
code and matching the trace data packets.

The decoder requests a buffer of binary data via a get_trace()
call-back, which it decodes using instruction information which it gets
via another call-back walk_insn().
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1437150840-31811-6-git-send-email-adrian.hunter@intel.com

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>