[PATCH 1/2] trace: add support for "trace clear"

[Ilias Apalodimas]

Thanks,

Apologies I missed something else as well

On Fri, 13 Dec 2024 at 14:14, Jerome Forissier
<jerome.forissier at linaro.org> wrote:
>
>
>
> On 12/13/24 13:09, Ilias Apalodimas wrote:
> > Hi Jerome
> >
> > On Mon, 9 Dec 2024 at 17:32, Jerome Forissier
> > <jerome.forissier at linaro.org> wrote:
> >>
> >> Implement a "trace clear" command to delete the currently accumulated
> >> trace data. This comes handy when someone needs to trace a particular
> >> command. For example:
> >>
> >>   => trace clear; dhcp; trace pause
> >>   => trace stats
> >>   => trace calls 0x02100000 0x10000000
> >>   => tftpput $profbase $profoffset 192.168.0.16:trace.bin
> >>
> >> Signed-off-by: Jerome Forissier <jerome.forissier at linaro.org>
> >> ---
> >>  cmd/trace.c     | 13 ++++++++++++-
> >>  include/trace.h |  2 ++
> >>  lib/trace.c     | 47 +++++++++++++++++++++++++++++++++--------------
> >>  3 files changed, 47 insertions(+), 15 deletions(-)
> >>
> >> diff --git a/cmd/trace.c b/cmd/trace.c
> >> index 937e6a682ad..e95ac7ca9da 100644
> >> --- a/cmd/trace.c
> >> +++ b/cmd/trace.c
> >> @@ -87,8 +87,18 @@ int do_trace(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
> >>                 trace_set_enabled(0);
> >>                 break;
> >>         case 'c':
> >> -               if (create_call_list(argc, argv))
> >> +               switch (*(cmd + 1)) {
> >> +               case 'a':
> >> +                       if (create_call_list(argc, argv))
> >> +                               return cmd_usage(cmdtp);
> >> +                       break;
> >> +               case 'l':
> >> +                       if (trace_clear())
> >> +                               return CMD_RET_FAILURE;
> >> +                       break;
> >
> > Instead of this, mind changing the command to trace wipe or something similar?
> > Then we can have a discrete case for 'w' rather than scanning for a string
>
> Good idea.
>
> Thanks,
> --
> Jerome
>
> >
> > Cheers
> > /Ilias
> >> +               default:
> >>                         return cmd_usage(cmdtp);
> >> +               }
> >>                 break;
> >>         case 'r':
> >>                 trace_set_enabled(1);
> >> @@ -113,6 +123,7 @@ U_BOOT_CMD(
> >>         "stats                        - display tracing statistics\n"
> >>         "trace pause                        - pause tracing\n"
> >>         "trace resume                       - resume tracing\n"
> >> +       "trace clear                        - clear traces\n"
> >>         "trace funclist [<addr> <size>]     - dump function list into buffer\n"
> >>         "trace calls  [<addr> <size>]       "
> >>                 "- dump function call trace into buffer"
> >> diff --git a/include/trace.h b/include/trace.h
> >> index 763d6d1255a..782eaae2fc2 100644
> >> --- a/include/trace.h
> >> +++ b/include/trace.h
> >> @@ -100,6 +100,8 @@ void trace_set_enabled(int enabled);
> >>
> >>  int trace_early_init(void);
> >>
> >> +int trace_clear(void);
> >> +
> >>  /**
> >>   * Init the trace system
> >>   *
> >> diff --git a/lib/trace.c b/lib/trace.c
> >> index cabbe47b58a..def9f912c92 100644
> >> --- a/lib/trace.c
> >> +++ b/lib/trace.c
> >> @@ -351,14 +351,8 @@ static int get_func_count(void)
> >>         return gd->mon_len / FUNC_SITE_SIZE;
> >>  }
> >>
> >> -/**
> >> - * trace_init() - initialize the tracing system and enable it
> >> - *
> >> - * @buff:      Pointer to trace buffer
> >> - * @buff_size: Size of trace buffer
> >> - * Return:     0 if ok
> >> - */
> >> -int notrace trace_init(void *buff, size_t buff_size)
> >> +static int notrace trace_init_(void *buff, size_t buff_size, bool copy_early,
> >> +                              bool enable)
> >>  {
> >>         int func_count = get_func_count();
> >>         size_t needed;
> >> @@ -368,7 +362,7 @@ int notrace trace_init(void *buff, size_t buff_size)
> >>                 return func_count;
> >>         trace_save_gd();
> >>
> >> -       if (!was_disabled) {
> >> +       if (copy_early) {
> >>  #ifdef CONFIG_TRACE_EARLY
> >>                 ulong used, count;
> >>                 char *end;
> >> @@ -394,9 +388,6 @@ int notrace trace_init(void *buff, size_t buff_size)
> >>                 }
> >>                 puts("\n");
> >>                 memcpy(buff, hdr, used);
> >> -#else
> >> -               puts("trace: already enabled\n");
> >> -               return -EALREADY;
> >>  #endif
> >>         }
> >>         hdr = (struct trace_hdr *)buff;
> >> @@ -419,13 +410,41 @@ int notrace trace_init(void *buff, size_t buff_size)
> >>         hdr->ftrace_size = (buff_size - needed) / sizeof(*hdr->ftrace);
> >>         hdr->depth_limit = CONFIG_TRACE_CALL_DEPTH_LIMIT;
> >>
> >> -       puts("trace: enabled\n");
> >> -       trace_enabled = 1;
> >> +       printf("trace: initialized, %senabled\n", enable ? "" : "not ");
> >> +       trace_enabled = enable;
> >>         trace_inited = 1;
> >>
> >>         return 0;
> >>  }
> >>
> >> +/**
> >> + * trace_init() - initialize the tracing system and enable it
> >> + *
> >> + * @buff:      Pointer to trace buffer
> >> + * @buff_size: Size of trace buffer
> >> + * Return:     0 if ok
> >> + */
> >> +int notrace trace_init(void *buff, size_t buff_size)
> >> +{
> >> +       /* If traces are enabled already, we may have early traces to copy */
> >> +       return trace_init_(buff, buff_size, trace_enabled, true);

This is a global, so you can skip passing it and just check the
trace_enabled in trace_init_()

Thanks
/Ilias
> >> +}
> >> +
> >> +/**
> >> + * trace_clear() - clear accumulated traced data
> >> + *
> >> + * May be called with tracing enabled or disabled.
> >> + */
> >> +int notrace trace_clear(void)
> >> +{
> >> +       bool was_enabled = trace_enabled;
> >> +
> >> +       if (trace_enabled)
> >> +               trace_enabled = 0;
> >> +       return trace_init_(gd->trace_buff, CONFIG_TRACE_BUFFER_SIZE,
> >> +                          false, was_enabled);
> >> +}
> >> +
> >>  #ifdef CONFIG_TRACE_EARLY
> >>  /**
> >>   * trace_early_init() - initialize the tracing system for early tracing
> >> --
> >> 2.43.0
> >>