Re: [PATCH] perf symbol: Add LoongArch case in get_plt_sizes()

[Tiezhu Yang]

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@xxxxxxxxxx> 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@xxxxxxxxxx> 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@xxxxxxxxxx> 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@xxxxxxxxxx>
> >
> > 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