Hi Ravi,

This code logic looks good. I just have several small comments for style.

On Tue, 13 Mar 2018 18:26:02 +0530
Ravi Bangoria <ravi.bango...@linux.vnet.ibm.com> wrote:

> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index e1dbc98..2cbe68a 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -1832,6 +1832,12 @@ int parse_probe_trace_command(const char *cmd, struct 
> probe_trace_event *tev)
>                       tp->offset = strtoul(fmt2_str, NULL, 10);
>       }
>  
> +     if (tev->uprobes) {
> +             fmt2_str = strchr(p, '(');
> +             if (fmt2_str)
> +                     tp->ref_ctr_offset = strtoul(fmt2_str + 1, NULL, 0);
> +     }
> +
>       tev->nargs = argc - 2;
>       tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
>       if (tev->args == NULL) {
> @@ -2054,15 +2060,22 @@ char *synthesize_probe_trace_command(struct 
> probe_trace_event *tev)
>       }
>  
>       /* Use the tp->address for uprobes */
> -     if (tev->uprobes)
> -             err = strbuf_addf(&buf, "%s:0x%lx", tp->module, tp->address);
> -     else if (!strncmp(tp->symbol, "0x", 2))
> +     if (tev->uprobes) {
> +             if (tp->ref_ctr_offset)
> +                     err = strbuf_addf(&buf, "%s:0x%lx(0x%lx)", tp->module,
> +                                       tp->address, tp->ref_ctr_offset);
> +             else
> +                     err = strbuf_addf(&buf, "%s:0x%lx", tp->module,
> +                                       tp->address);
> +     } else if (!strncmp(tp->symbol, "0x", 2)) {
>               /* Absolute address. See try_to_find_absolute_address() */
>               err = strbuf_addf(&buf, "%s%s0x%lx", tp->module ?: "",
>                                 tp->module ? ":" : "", tp->address);
> -     else
> +     } else {
>               err = strbuf_addf(&buf, "%s%s%s+%lu", tp->module ?: "",
>                               tp->module ? ":" : "", tp->symbol, tp->offset);
> +     }

What the purpose of this {}?

> +
>       if (err)
>               goto error;
>  
> diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
> index 45b14f0..15a98c3 100644
> --- a/tools/perf/util/probe-event.h
> +++ b/tools/perf/util/probe-event.h
> @@ -27,6 +27,7 @@ struct probe_trace_point {
>       char            *symbol;        /* Base symbol */
>       char            *module;        /* Module name */
>       unsigned long   offset;         /* Offset from symbol */
> +     unsigned long   ref_ctr_offset; /* SDT reference counter offset */
>       unsigned long   address;        /* Actual address of the trace point */
>       bool            retprobe;       /* Return probe flag */
>  };
> diff --git a/tools/perf/util/probe-file.c b/tools/perf/util/probe-file.c
> index 4ae1123..08ba3a6 100644
> --- a/tools/perf/util/probe-file.c
> +++ b/tools/perf/util/probe-file.c
> @@ -701,6 +701,12 @@ static unsigned long long sdt_note__get_addr(struct 
> sdt_note *note)
>                : (unsigned long long)note->addr.a64[0];
>  }
>  
> +static unsigned long long sdt_note__get_ref_ctr_offset(struct sdt_note *note)
> +{
> +     return note->bit32 ? (unsigned long long)note->addr.a32[2]
> +             : (unsigned long long)note->addr.a64[2];
> +}

Could you please introduce an enum for specifying the index by name?

e.g.
enum {
        SDT_NOTE_IDX_ADDR = 0,
        SDT_NOTE_IDX_REFCTR = 2,
};

> +
>  static const char * const type_to_suffix[] = {
>       ":s64", "", "", "", ":s32", "", ":s16", ":s8",
>       "", ":u8", ":u16", "", ":u32", "", "", "", ":u64"
> @@ -776,14 +782,24 @@ static char *synthesize_sdt_probe_command(struct 
> sdt_note *note,
>  {
>       struct strbuf buf;
>       char *ret = NULL, **args;
> -     int i, args_count;
> +     int i, args_count, err;
> +     unsigned long long ref_ctr_offset;
>  
>       if (strbuf_init(&buf, 32) < 0)
>               return NULL;
>  
> -     if (strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
> +     ref_ctr_offset = sdt_note__get_ref_ctr_offset(note);
> +
> +     if (ref_ctr_offset)
> +             err = strbuf_addf(&buf, "p:%s/%s %s:0x%llx(0x%llx)",
>                               sdtgrp, note->name, pathname,
> -                             sdt_note__get_addr(note)) < 0)
> +                             sdt_note__get_addr(note), ref_ctr_offset);
> +     else
> +             err = strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
> +                             sdtgrp, note->name, pathname,
> +                             sdt_note__get_addr(note));

This can be minimized (and avoid repeating) by using 2 strbuf_addf()s, like

        err = strbuf_addf(&buf, "p:%s/%s %s:0x%llx",
                        sdtgrp, note->name, pathname,
                        sdt_note__get_addr(note));
        if (ref_ctr_offset && !err < 0)
                err = strbuf_addf("(0x%llx)", ref_ctr_offset);


> +
> +     if (err < 0)
>               goto error;
>  
>       if (!note->args)
> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> index 2de7705..76c7b54 100644
> --- a/tools/perf/util/symbol-elf.c
> +++ b/tools/perf/util/symbol-elf.c
> @@ -1928,6 +1928,16 @@ static int populate_sdt_note(Elf **elf, const char 
> *data, size_t len,
>               }
>       }
>  
> +     /* Adjust reference counter offset */
> +     if (elf_section_by_name(*elf, &ehdr, &shdr, SDT_PROBES_SCN, NULL)) {
> +             if (shdr.sh_offset) {
> +                     if (tmp->bit32)
> +                             tmp->addr.a32[2] -= (shdr.sh_addr - 
> shdr.sh_offset);
> +                     else
> +                             tmp->addr.a64[2] -= (shdr.sh_addr - 
> shdr.sh_offset);

Here we should use enum above too.

Thank you,

> +             }
> +     }
> +
>       list_add_tail(&tmp->note_list, sdt_notes);
>       return 0;
>  
> diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
> index 70c16741..ad0c4f2 100644
> --- a/tools/perf/util/symbol.h
> +++ b/tools/perf/util/symbol.h
> @@ -384,6 +384,7 @@ struct sdt_note {
>  int cleanup_sdt_note_list(struct list_head *sdt_notes);
>  int sdt_notes__get_count(struct list_head *start);
>  
> +#define SDT_PROBES_SCN ".probes"
>  #define SDT_BASE_SCN ".stapsdt.base"
>  #define SDT_NOTE_SCN  ".note.stapsdt"
>  #define SDT_NOTE_TYPE 3
> -- 
> 1.8.3.1
> 


-- 
Masami Hiramatsu <mhira...@kernel.org>
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