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Subject: Re: [PATCH] perf symbol: Add LoongArch case in get_plt_sizes()
To:     Huacai Chen <chenhuacai@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
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Cc:     Leo Yan <leo.yan@linaro.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        linux-perf-users@vger.kernel.org, loongarch@lists.linux.dev,
        linux-kernel@vger.kernel.org, loongson-kernel@lists.loongnix.cn
From:   Tiezhu Yang <yangtiezhu@loongson.cn>
Message-ID: <387463f9-adb0-8e98-1de6-cae7a79a7d03@loongson.cn>
Date:   Mon, 22 May 2023 15:58:55 +0800
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On 05/22/2023 11:50 AM, Huacai Chen wrote:
> Hi, Arnaldo,
>
> On Thu, May 18, 2023 at 8:16 PM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
>>
>> Em Thu, May 18, 2023 at 12:05:53PM +0800, Leo Yan escreveu:
>>> On Thu, May 18, 2023 at 11:57:29AM +0800, Huacai Chen wrote:
>>>> On Thu, May 18, 2023 at 11:21 AM Leo Yan <leo.yan@linaro.org> wrote:
>>>>>
>>>>> On Thu, May 18, 2023 at 11:12:26AM +0800, Huacai Chen wrote:
>>>>>> On Thu, May 18, 2023 at 11:06 AM Leo Yan <leo.yan@linaro.org> wrote:
>>>>>>>
>>>>>>> On Thu, May 18, 2023 at 10:11:27AM +0800, Huacai Chen wrote:
>>>>>>>> Queued, thanks.
>>>>>>>
>>>>>>> The patch is fine for me.
>>>>>>>
>>>>>>> Should not perf patches are to be merged via Arnaldo's tree?
>>>>>>
>>>>>> I think both are OK, if Arnaldo takes this patch, I will drop it.
>>>>>
>>>>> A good practice is to firstly inquiry the maintainers.
>>>>>
>>>>> AFAIK, Arnaldo will test perf patches before sending out pull request;
>>>>> if perf patches are scattered out, it might be out of the testing
>>>>> radar.
>>>> OK, I know, thank you very much.
>>>
>>> You are welcome!
>>>
>>> I found the code base for bfd:
>>> https://github.com/bminor/binutils-gdb/blob/master/bfd/elfnn-loongarch.c
>>>
>>> And this patch is consistent with above link, FWIW:
>>>
>>> Reviewed-by: Leo Yan <leo.yan@linaro.org>
>>
>> Thanks, applied.
> I'm very sorry that this patch breaks cross-build. We need some
> additional modification.
>
> diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
> index 5d409c26a22e..b3dbf6ca99a7 100644
> --- a/tools/perf/util/symbol-elf.c
> +++ b/tools/perf/util/symbol-elf.c
> @@ -35,6 +35,10 @@
>  #define EM_AARCH64     183  /* ARM 64 bit */
>  #endif
>
> +#ifndef EM_LOONGARCH
> +#define EM_LOONGARCH   258
> +#endif
> +
>  #ifndef ELF32_ST_VISIBILITY
>  #define ELF32_ST_VISIBILITY(o) ((o) & 0x03)
>  #endif
>
> Then, drop this patch to get an updated version, or let me send an
> incremental patch?
>

I tested this patch on native LoongArch and x86 system, I did not
hit the build error about undeclared EM_LOONGARCH both on LoongArch
and x86, because EM_LOONGARCH is defined in /usr/include/elf.h

Here is the x86 system info:

[root@fedora yangtiezhu]# cat /etc/fedora-release
Fedora release 38 (Thirty Eight)
[root@fedora yangtiezhu]# uname -m
x86_64
[root@fedora yangtiezhu]# grep -rn -w EM_LOONGARCH /usr/include/
/usr/include/linux/elf-em.h:54:#define EM_LOONGARCH    258    /* 
LoongArch */
/usr/include/linux/audit.h:442:#define AUDIT_ARCH_LOONGARCH32 
(EM_LOONGARCH|__AUDIT_ARCH_LE)
/usr/include/linux/audit.h:443:#define AUDIT_ARCH_LOONGARCH64 
(EM_LOONGARCH|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE)
/usr/include/elf.h:361:#define EM_LOONGARCH    258    /* LoongArch */
[root@fedora yangtiezhu]# rpm -qf /usr/include/elf.h
glibc-headers-x86-2.37-1.fc38.noarch

If I am missing something, please let me know.

Anyway, it is not a bad thing to add the EM_LOONGARCH definition
to avoid the build error on some systems which have no EM_LOONGARCH
in the glibc header.

Thanks,
Tiezhu