[PATCH v3 08/18] perf cs-etm: Use instruction length in disassembly script

[James Clark]

The disassembly script adds four bytes to each branch sample's IP to
include the final instruction in the range. For an exception sample
whose IP identifies a faulting or interrupted instruction, this
incorrectly includes an instruction that did not execute.

Use the decoder-supplied insn_len to calculate the exclusive end
address. This preserves zero-length exception entries, includes executed
syscall instructions and also uses the decoded size for Thumb
instructions.

Signed-off-by: James Clark <james.clark at linaro.org>
---
 tools/perf/python/arm-cs-trace-disasm.py | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/tools/perf/python/arm-cs-trace-disasm.py b/tools/perf/python/arm-cs-trace-disasm.py
index 5a7daf927bea..7cf0af5d2780 100755
--- a/tools/perf/python/arm-cs-trace-disasm.py
+++ b/tools/perf/python/arm-cs-trace-disasm.py
@@ -315,11 +315,12 @@ class TraceDisasm:
         #     [ sample_prev::addr .. sample_next::ip ]
         #
         # sample_prev::addr is stored into cpu_data and read back as
-        # 'start_addr' when the new packet arrives, and sample_next::ip + 4 is
-        # used for 'stop_addr' so objdump includes the branch instruction at
-        # sample_next::ip.
+        # 'start_addr' when the new packet arrives. Add sample_next::insn_len
+        # to sample_next::ip so objdump includes the last executed instruction.
+        # The decoder supplies a zero length for an unexecuted instruction at
+        # an exception entry, excluding it from the range.
         start_addr = self.cpu_data[str(cpu) + 'addr']
-        stop_addr  = ip + 4
+        stop_addr = ip + sample.insn_len
 
         # Record for previous sample packet
         self.cpu_data[str(cpu) + 'addr'] = addr

-- 
2.43.0