linux-kernel - Re: [PATCH] perf parse-events: Use uintptr

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Date:   Thu, 3 Sep 2020 22:31:09 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:     Jin Yao <yao.jin@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Andi Kleen <ak@...ux.intel.com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Jiri Olsa <jolsa@...nel.org>,
        John Garry <john.garry@...wei.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Mark Rutland <mark.rutland@....com>,
        Martin KaFai Lau <kafai@...com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Song Liu <songliubraving@...com>,
        Stephane Eranian <eranian@...gle.com>,
        Yonghong Song <yhs@...com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] perf parse-events: Use uintptr_t when casting numbers to pointers

On Thu, Sep 3, 2020 at 11:44 AM Arnaldo Carvalho de Melo
<acme@...nel.org> wrote:
>
> Hi Ian,
>
>         Please check that this is ok with you,
>
> Thanks,
>
> - Arnaldo

Thanks Arnaldo, this looks good to me! There is a separate issue, the
casts are necessary as we have PE_VALUEs that are supposed to be
numbers but here are list*. It seems error prone to have something
that is a pointer or a number, and so I wonder if we can introduce new
tokens in parse-events.y to handle this. It'd also mean that
yydestructors and the like could clean up error states. I'll try to
take a look.

Thanks,
Ian

> commit 0823f768b800cca2592fad3b5649766ae6bc4eba
> Author: Arnaldo Carvalho de Melo <acme@...hat.com>
> Date:   Thu Sep 3 15:34:20 2020 -0300
>
>     perf parse-events: Use uintptr_t when casting numbers to pointers
>
>     To address these errors found when cross building from x86_64 to MIPS
>     little endian 32-bit:
>
>         CC       /tmp/build/perf/util/parse-events-bison.o
>       util/parse-events.y: In function 'parse_events_parse':
>       util/parse-events.y:514:6: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>         514 |      (void *) $2, $6, $4);
>             |      ^
>       util/parse-events.y:531:7: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>         531 |       (void *) $2, NULL, $4)) {
>             |       ^
>       util/parse-events.y:547:6: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>         547 |      (void *) $2, $4, 0);
>             |      ^
>       util/parse-events.y:564:7: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast]
>         564 |       (void *) $2, NULL, 0)) {
>             |       ^
>
>     Fixes: cabbf26821aa210f ("perf parse: Before yyabort-ing free components")
>     Cc: Adrian Hunter <adrian.hunter@...el.com>
>     Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
>     Cc: Alexei Starovoitov <ast@...nel.org>
>     Cc: Andi Kleen <ak@...ux.intel.com>
>     Cc: Daniel Borkmann <daniel@...earbox.net>
>     Cc: Ian Rogers <irogers@...gle.com>
>     Cc: Jin Yao <yao.jin@...ux.intel.com>
>     Cc: Jiri Olsa <jolsa@...nel.org>
>     Cc: John Garry <john.garry@...wei.com>
>     Cc: Kan Liang <kan.liang@...ux.intel.com>
>     Cc: Mark Rutland <mark.rutland@....com>
>     Cc: Martin KaFai Lau <kafai@...com>
>     Cc: Namhyung Kim <namhyung@...nel.org>
>     Cc: Peter Zijlstra <peterz@...radead.org>
>     Cc: Song Liu <songliubraving@...com>
>     Cc: Stephane Eranian <eranian@...gle.com>
>     Cc: Yonghong Song <yhs@...com>
>     Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
>
> diff --git a/tools/perf/util/parse-events.y b/tools/perf/util/parse-events.y
> index b9fb91fdc5de9177..645bf4f1859fd76b 100644
> --- a/tools/perf/util/parse-events.y
> +++ b/tools/perf/util/parse-events.y
> @@ -511,7 +511,7 @@ PE_PREFIX_MEM PE_VALUE '/' PE_VALUE ':' PE_MODIFIER_BP sep_dc
>         list = alloc_list();
>         ABORT_ON(!list);
>         err = parse_events_add_breakpoint(list, &parse_state->idx,
> -                                       (void *) $2, $6, $4);
> +                                       (void *)(uintptr_t) $2, $6, $4);
>         free($6);
>         if (err) {
>                 free(list);
> @@ -528,7 +528,7 @@ PE_PREFIX_MEM PE_VALUE '/' PE_VALUE sep_dc
>         list = alloc_list();
>         ABORT_ON(!list);
>         if (parse_events_add_breakpoint(list, &parse_state->idx,
> -                                               (void *) $2, NULL, $4)) {
> +                                               (void *)(uintptr_t) $2, NULL, $4)) {
>                 free(list);
>                 YYABORT;
>         }
> @@ -544,7 +544,7 @@ PE_PREFIX_MEM PE_VALUE ':' PE_MODIFIER_BP sep_dc
>         list = alloc_list();
>         ABORT_ON(!list);
>         err = parse_events_add_breakpoint(list, &parse_state->idx,
> -                                       (void *) $2, $4, 0);
> +                                       (void *)(uintptr_t) $2, $4, 0);
>         free($4);
>         if (err) {
>                 free(list);
> @@ -561,7 +561,7 @@ PE_PREFIX_MEM PE_VALUE sep_dc
>         list = alloc_list();
>         ABORT_ON(!list);
>         if (parse_events_add_breakpoint(list, &parse_state->idx,
> -                                               (void *) $2, NULL, 0)) {
> +                                               (void *)(uintptr_t) $2, NULL, 0)) {
>                 free(list);
>                 YYABORT;
>         }