The exception packet appears as one element with 'elem_type' ==
OCSD_GEN_TRC_ELEM_EXCEPTION or OCSD_GEN_TRC_ELEM_EXCEPTION_RET, which is
present for exception entry and exit respectively. The decoder sets the
packet fields 'packet->exc' and 'packet->exc_ret' to indicate the
exception packets; but exception packets don't have a dedicated sample
type and shares the same sample type CS_ETM_RANGE with normal
instruction packets.
As a result, the exception packets are taken as normal instruction
packets and this introduces confusion in mixing different packet types.
Furthermore, these instruction range packets will be processed for
branch samples only when 'packet->last_instr_taken_branch' is true,
otherwise they will be omitted, this can introduce a mess for exception
and exception returning due to not having the complete address range
info for context switching.
To process exception packets properly, this patch introduces two new
sample types: CS_ETM_EXCEPTION and CS_ETM_EXCEPTION_RET; these two types
of packets will be handled by cs_etm__exception(). The function
cs_etm__exception() forces setting the previous CS_ETM_RANGE packet flag
'prev_packet->last_instr_taken_branch' to true, this matches well with
the program flow when the exception is trapped from user space to kernel
space, no matter if the most recent flow has branch taken or not; this
is also safe for returning to user space after exception handling.
After exception packets have their own sample type, the packet fields
'packet->exc' and 'packet->exc_ret' aren't needed anymore, so remove
them.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight ml <coresight@lists.linaro.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-9-git-send-email-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
TRACE_ON element is used at the beginning of trace, it also can be
appeared in the middle of trace data to indicate discontinuity; for
example, it's possible to see multiple TRACE_ON elements in the trace
stream if the trace is being limited by address range filtering.
Furthermore, except TRACE_ON element is for discontinuity, NO_SYNC and
EO_TRACE also can be used to indicate discontinuity, though they are
used for different scenarios for which the trace is interrupted.
This patch renames sample type CS_ETM_TRACE_ON to CS_ETM_DISCONTINUITY,
firstly the new name describes more closely the purpose of the packet;
secondly this is a preparation for other output elements which also
cause the trace discontinuity thus they can share the same one packet
type.
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Robert Walker <robert.walker@arm.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1544513908-16805-6-git-send-email-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Added user space perf functionality to translate CoreSight traces into
instruction events with branch stack.
To invoke the new functionality, use the perf inject tool with
--itrace=il. For example, to translate the ETM trace from perf.data into
last branch records in a new inj.data file:
$ perf inject --itrace=i100000il128 -i perf.data -o perf.data.new
The 'i' parameter to itrace generates periodic instruction events. The
period between instruction events can be specified as a number of
instructions suffixed by i (default 100000).
The parameter to 'l' specifies the number of entries in the branch stack
attached to instruction events.
The 'b' parameter to itrace generates events on taken branches.
This patch also fixes the contents of the branch events used in perf
report - previously branch events were generated for each contiguous
range of instructions executed. These are fixed to generate branch
events between the last address of a range ending in an executed branch
instruction and the start address of the next range.
Based on patches by Sebastian Pop <s.pop@samsung.com> with additional fixes
and support for specifying the instruction period.
Originally-by: Sebastian Pop <s.pop@samsung.com>
Signed-off-by: Robert Walker <robert.walker@arm.com>
Acked-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/1518607481-4059-2-git-send-email-robert.walker@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
