Re: [PATCH v2 5/7] perf scripts python cs-etm: Improve arguments

[Leo Yan]

On 9/12/24 16:11, James Clark wrote:
> Make vmlinux detection automatic and use Perf's default objdump
> when -d is specified. This will make it easier for a test to use the
> script without having to provide arguments. And similarly for users.
>
> Signed-off-by: James Clark <james.clark@xxxxxxxxxx>

Reviewed-by: Leo Yan <leo.yan@xxxxxxx>

> ---
>   .../scripts/python/arm-cs-trace-disasm.py     | 63 ++++++++++++++++---
>   1 file changed, 55 insertions(+), 8 deletions(-)
>
> diff --git a/tools/perf/scripts/python/arm-cs-trace-disasm.py b/tools/perf/scripts/python/arm-cs-trace-disasm.py
> index 45f682a8b34d..02e957d037ea 100755
> --- a/tools/perf/scripts/python/arm-cs-trace-disasm.py
> +++ b/tools/perf/scripts/python/arm-cs-trace-disasm.py
> @@ -12,25 +12,48 @@ from os import path
>   import re
>   from subprocess import *
>   import argparse
> +import platform
>
> -from perf_trace_context import perf_set_itrace_options, \
> -       perf_sample_insn, perf_sample_srccode
> +from perf_trace_context import perf_sample_srccode, perf_config_get
>
>   # Below are some example commands for using this script.
> +# Note a --kcore recording is required for accurate decode
> +# due to the alternatives patching mechanism. However this
> +# script only supports reading vmlinux for disassembly dump,
> +# meaning that any patched instructions will appear
> +# as unpatched, but the instruction ranges themselves will
> +# be correct. In addition to this, source line info comes
> +# from Perf, and when using kcore there is no debug info. The
> +# following lists the supported features in each mode:
> +#
> +# +-----------+-----------------+------------------+------------------+
> +# | Recording | Accurate decode | Source line dump | Disassembly dump |
> +# +-----------+-----------------+------------------+------------------+
> +# | --kcore   | yes             | no               | yes              |
> +# | normal    | no              | yes              | yes              |
> +# +-----------+-----------------+------------------+------------------+
> +#
> +# Output disassembly with objdump and auto detect vmlinux
> +# (when running on same machine.)
> +#  perf script -s scripts/python/arm-cs-trace-disasm.py -d
>   #
> -# Output disassembly with objdump:
> -#  perf script -s scripts/python/arm-cs-trace-disasm.py \
> -#              -- -d objdump -k path/to/vmlinux
>   # Output disassembly with llvm-objdump:
>   #  perf script -s scripts/python/arm-cs-trace-disasm.py \
>   #              -- -d llvm-objdump-11 -k path/to/vmlinux
> +#
>   # Output only source line and symbols:
>   #  perf script -s scripts/python/arm-cs-trace-disasm.py
>
> +def default_objdump():
> +       config = perf_config_get("annotate.objdump")
> +       return config if config else "objdump"
> +
>   # Command line parsing.
>   args = argparse.ArgumentParser()
> -args.add_argument("-k", "--vmlinux", help="Set path to vmlinux file")
> -args.add_argument("-d", "--objdump", help="Set path to objdump executable file"),
> +args.add_argument("-k", "--vmlinux",
> +                 help="Set path to vmlinux file. Omit to autodetect if running on same machine")
> +args.add_argument("-d", "--objdump", nargs="?", const=default_objdump(),
> +                 help="Show disassembly. Can also be used to change the objdump path"),
>   args.add_argument("-v", "--verbose", action="store_true", help="Enable debugging log")
>   options = args.parse_args()
>
> @@ -45,6 +68,17 @@ glb_source_file_name = None
>   glb_line_number                = None
>   glb_dso                        = None
>
> +kver = platform.release()
> +vmlinux_paths = [
> +       f"/usr/lib/debug/boot/vmlinux-{kver}.debug",
> +       f"/usr/lib/debug/lib/modules/{kver}/vmlinux",
> +       f"/lib/modules/{kver}/build/vmlinux",
> +       f"/usr/lib/debug/boot/vmlinux-{kver}",
> +       f"/boot/vmlinux-{kver}",
> +       f"/boot/vmlinux",
> +       f"vmlinux"
> +]
> +
>   def get_optional(perf_dict, field):
>          if field in perf_dict:
>                  return perf_dict[field]
> @@ -55,12 +89,25 @@ def get_offset(perf_dict, field):
>                  return "+%#x" % perf_dict[field]
>          return ""
>
> +def find_vmlinux():
> +       if hasattr(find_vmlinux, "path"):
> +               return find_vmlinux.path
> +
> +       for v in vmlinux_paths:
> +               if os.access(v, os.R_OK):
> +                       find_vmlinux.path = v
> +                       break
> +       else:
> +               find_vmlinux.path = None
> +
> +       return find_vmlinux.path
> +
>   def get_dso_file_path(dso_name, dso_build_id):
>          if (dso_name == "[kernel.kallsyms]" or dso_name == "vmlinux"):
>                  if (options.vmlinux):
>                          return options.vmlinux;
>                  else:
> -                       return dso_name
> +                       return find_vmlinux() if find_vmlinux() else dso_name
>
>          if (dso_name == "[vdso]") :
>                  append = "/vdso"
> --
> 2.34.1