* [PATCH] perf jit: Fix inaccurate DWARF line table
@ 2020-05-28 5:19 Nick Gasson
2020-05-28 7:44 ` Ian Rogers
0 siblings, 1 reply; 3+ messages in thread
From: Nick Gasson @ 2020-05-28 5:19 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo, Jiri Olsa, Ian Rogers, Peter Zijlstra,
Stephane Eranian
Cc: Nick Gasson, linux-kernel
Fix an issue where addresses in the DWARF line table are offset by
-0x40 (GEN_ELF_TEXT_OFFSET). This can be seen with `objdump -S` on the
ELF files after perf inject.
Signed-off-by: Nick Gasson <nick.gasson@arm.com>
---
tools/perf/util/genelf_debug.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/perf/util/genelf_debug.c b/tools/perf/util/genelf_debug.c
index 30e9f618f6cd..dd40683bd4c0 100644
--- a/tools/perf/util/genelf_debug.c
+++ b/tools/perf/util/genelf_debug.c
@@ -342,7 +342,7 @@ static void emit_lineno_info(struct buffer_ext *be,
*/
/* start state of the state machine we take care of */
- unsigned long last_vma = code_addr;
+ unsigned long last_vma = 0;
char const *cur_filename = NULL;
unsigned long cur_file_idx = 0;
int last_line = 1;
@@ -473,7 +473,7 @@ jit_process_debug_info(uint64_t code_addr,
ent = debug_entry_next(ent);
}
add_compilation_unit(di, buffer_ext_size(dl));
- add_debug_line(dl, debug, nr_debug_entries, 0);
+ add_debug_line(dl, debug, nr_debug_entries, GEN_ELF_TEXT_OFFSET);
add_debug_abbrev(da);
if (0) buffer_ext_dump(da, "abbrev");
--
2.26.2
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] perf jit: Fix inaccurate DWARF line table
2020-05-28 5:19 [PATCH] perf jit: Fix inaccurate DWARF line table Nick Gasson
@ 2020-05-28 7:44 ` Ian Rogers
2020-05-29 16:02 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 3+ messages in thread
From: Ian Rogers @ 2020-05-28 7:44 UTC (permalink / raw)
To: Nick Gasson
Cc: Arnaldo Carvalho de Melo, Jiri Olsa, Peter Zijlstra,
Stephane Eranian, LKML
On Wed, May 27, 2020 at 10:19 PM Nick Gasson <nick.gasson@arm.com> wrote:
>
> Fix an issue where addresses in the DWARF line table are offset by
> -0x40 (GEN_ELF_TEXT_OFFSET). This can be seen with `objdump -S` on the
> ELF files after perf inject.
Without too much knowledge this looks good to me. The original code
came from oprofile's jit support:
https://sourceforge.net/p/oprofile/oprofile/ci/master/tree/opjitconv/debug_line.c#l325
Acked-by: Ian Rogers <irogers@google.com>
> Signed-off-by: Nick Gasson <nick.gasson@arm.com>
> ---
> tools/perf/util/genelf_debug.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/genelf_debug.c b/tools/perf/util/genelf_debug.c
> index 30e9f618f6cd..dd40683bd4c0 100644
> --- a/tools/perf/util/genelf_debug.c
> +++ b/tools/perf/util/genelf_debug.c
> @@ -342,7 +342,7 @@ static void emit_lineno_info(struct buffer_ext *be,
> */
>
> /* start state of the state machine we take care of */
> - unsigned long last_vma = code_addr;
> + unsigned long last_vma = 0;
> char const *cur_filename = NULL;
> unsigned long cur_file_idx = 0;
> int last_line = 1;
> @@ -473,7 +473,7 @@ jit_process_debug_info(uint64_t code_addr,
> ent = debug_entry_next(ent);
> }
> add_compilation_unit(di, buffer_ext_size(dl));
> - add_debug_line(dl, debug, nr_debug_entries, 0);
> + add_debug_line(dl, debug, nr_debug_entries, GEN_ELF_TEXT_OFFSET);
> add_debug_abbrev(da);
> if (0) buffer_ext_dump(da, "abbrev");
>
> --
> 2.26.2
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] perf jit: Fix inaccurate DWARF line table
2020-05-28 7:44 ` Ian Rogers
@ 2020-05-29 16:02 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2020-05-29 16:02 UTC (permalink / raw)
To: Ian Rogers; +Cc: Nick Gasson, Jiri Olsa, Peter Zijlstra, Stephane Eranian, LKML
Em Thu, May 28, 2020 at 12:44:56AM -0700, Ian Rogers escreveu:
> On Wed, May 27, 2020 at 10:19 PM Nick Gasson <nick.gasson@arm.com> wrote:
> >
> > Fix an issue where addresses in the DWARF line table are offset by
> > -0x40 (GEN_ELF_TEXT_OFFSET). This can be seen with `objdump -S` on the
> > ELF files after perf inject.
>
> Without too much knowledge this looks good to me. The original code
> came from oprofile's jit support:
> https://sourceforge.net/p/oprofile/oprofile/ci/master/tree/opjitconv/debug_line.c#l325
>
> Acked-by: Ian Rogers <irogers@google.com>
Thanks, applied and added your comment,
- Arnaldo
> > Signed-off-by: Nick Gasson <nick.gasson@arm.com>
> > ---
> > tools/perf/util/genelf_debug.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/perf/util/genelf_debug.c b/tools/perf/util/genelf_debug.c
> > index 30e9f618f6cd..dd40683bd4c0 100644
> > --- a/tools/perf/util/genelf_debug.c
> > +++ b/tools/perf/util/genelf_debug.c
> > @@ -342,7 +342,7 @@ static void emit_lineno_info(struct buffer_ext *be,
> > */
> >
> > /* start state of the state machine we take care of */
> > - unsigned long last_vma = code_addr;
> > + unsigned long last_vma = 0;
> > char const *cur_filename = NULL;
> > unsigned long cur_file_idx = 0;
> > int last_line = 1;
> > @@ -473,7 +473,7 @@ jit_process_debug_info(uint64_t code_addr,
> > ent = debug_entry_next(ent);
> > }
> > add_compilation_unit(di, buffer_ext_size(dl));
> > - add_debug_line(dl, debug, nr_debug_entries, 0);
> > + add_debug_line(dl, debug, nr_debug_entries, GEN_ELF_TEXT_OFFSET);
> > add_debug_abbrev(da);
> > if (0) buffer_ext_dump(da, "abbrev");
> >
> > --
> > 2.26.2
> >
--
- Arnaldo
^ permalink raw reply [flat|nested] 3+ messages in thread
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