[RFC 0/9] Remove legacy platform bits and cleanups

Tue Jun 18 08:55:57 GMT 2024

On 12.06.24 09:50, Stefan Liebler wrote:
> On 11.06.24 14:13, Stefan Liebler wrote:
>> On 10.06.24 15:36, Stefan Liebler wrote:
>>> On 08.06.24 13:09, Florian Weimer wrote:
>>>> * Stefan Liebler:
>>>>
>>>>> This patch series is the result of:
>>>>> "Question regarding platform-bits in ld.so.cache"
>>>>> https://sourceware.org/pipermail/libc-alpha/2024-May/156793.html
>>>>
>>>> This series fails to build on MIPS with:
>>>>
>>>> mips64-glibc-linux-gnu-gcc -mabi=32 ldconfig.c -c -std=gnu11 -fgnu89-inline  -g -O2 -Wall -Wwrite-strings -Wundef -Werror -fmerge-all-constants -frounding-math -fno-stack-protector -fno-common -Wp,-U_FORTIFY_SOURCE -Wstrict-prototypes -Wold-style-definition -fmath-errno -D_TIME_BITS=64 -D_FILE_OFFSET_BITS=64   -fPIE    -Wa,-execstack -D'SYSCONFDIR="/etc"' -D'LIBDIR="/usr/lib"' -D'SLIBDIR="/lib"'       -I../include -I/home/bmg/build/glibcs/mips-linux-gnu/glibc/elf  -I/home/bmg/build/glibcs/mips-linux-gnu/glibc  -I../sysdeps/unix/sysv/linux/mips/mips32/fpu  -I../sysdeps/unix/sysv/linux/mips/mips32  -I../sysdeps/unix/sysv/linux/mips  -I../sysdeps/mips/nptl  -I../sysdeps/unix/sysv/linux/include -I../sysdeps/unix/sysv/linux  -I../sysdeps/nptl  -I../sysdeps/pthread  -I../sysdeps/gnu  -I../sysdeps/unix/inet  -I../sysdeps/unix/sysv  -I../sysdeps/unix/mips/mips32  -I../sysdeps/unix/mips  -I../sysdeps/unix  -I../sysdeps/posix  -I../sysdeps/mips/mips32/fpu  -I../sysdeps/mips/mips32  -I../sysdeps/mips/ieee754  -I../sysdeps/mips/include -I../sysdeps/mips  -I../sysdeps/ieee754/flt-32  -I../sysdeps/ieee754/dbl-64  -I../sysdeps/wordsize-32  -I../sysdeps/mips/fpu  -I../sysdeps/ieee754  -I../sysdeps/generic  -I.. -I../libio -I.   -D_LIBC_REENTRANT -include /home/bmg/build/glibcs/mips-linux-gnu/glibc/libc-modules.h -DMODULE_NAME=ldconfig -include ../include/libc-symbols.h  -DPIC     -DTOP_NAMESPACE=glibc -o /home/bmg/build/glibcs/mips-linux-gnu/glibc/elf/ldconfig.o -MD -MP -MF /home/bmg/build/glibcs/mips-linux-gnu/glibc/elf/ldconfig.o.dt -MT /home/bmg/build/glibcs/mips-linux-gnu/glibc/elf/ldconfig.o
>>>> In file included from ../sysdeps/generic/ldsodefs.h:643,
>>>>                  from ../sysdeps/mips/ldsodefs.h:82,
>>>>                  from ../sysdeps/gnu/ldsodefs.h:46,
>>>>                  from ../sysdeps/unix/sysv/linux/ldsodefs.h:25,
>>>>                  from ../sysdeps/unix/sysv/linux/mips/ldsodefs.h:22,
>>>>                  from ../sysdeps/mips/dl-procinfo.h:22,
>>>>                  from /home/bmg/build/glibcs/mips-linux-gnu/glibc/dl-tunable-list.h:6,
>>>>                  from ../elf/dl-tunables.h:48,
>>>>                  from ./dl-hwcaps.h:25,
>>>>                  from ldconfig.c:44:
>>>> ../sysdeps/unix/sysv/linux/dl-vdso-setup.c:62:22: error: ‘_dl_vdso_clock_getres’ defined but not used [-Werror=unused-variable]
>>>>    62 | PROCINFO_CLASS int (*_dl_vdso_clock_getres) (clockid_t,
>>>>       |                      ^~~~~~~~~~~~~~~~~~~~~
>>>> ../sysdeps/unix/sysv/linux/dl-vdso-setup.c:53:22: error: ‘_dl_vdso_gettimeofday’ defined but not used [-Werror=unused-variable]
>>>>    53 | PROCINFO_CLASS int (*_dl_vdso_gettimeofday) (struct timeval *, void *) RELRO;
>>>>       |                      ^~~~~~~~~~~~~~~~~~~~~
>>>> ../sysdeps/unix/sysv/linux/dl-vdso-setup.c:49:22: error: ‘_dl_vdso_clock_gettime64’ defined but not used [-Werror=unused-variable]
>>>>    49 | PROCINFO_CLASS int (*_dl_vdso_clock_gettime64) (clockid_t,
>>>>       |                      ^~~~~~~~~~~~~~~~~~~~~~~~
>>>> ../sysdeps/unix/sysv/linux/dl-vdso-setup.c:45:22: error: ‘_dl_vdso_clock_gettime’ defined but not used [-Werror=unused-variable]
>>>>    45 | PROCINFO_CLASS int (*_dl_vdso_clock_gettime) (clockid_t,
>>>>       |                      ^~~~~~~~~~~~~~~~~~~~~~
>>>> cc1: all warnings being treated as errors
>>>> make[3]: *** [../o-iterator.mk:9: /home/bmg/build/glibcs/mips-linux-gnu/glibc/elf/ldconfig.o] Error 1
>>>> make[3]: Leaving directory '/home/bmg/src/glibc/elf'
>>>> make[3]: *** Waiting for unfinished jobs....
>>>> make[2]: *** [Makefile:484: elf/others] Error 2
>>>> make[1]: *** [Makefile:9: all] Error 2
>>>>
>>>> Florian
>>>>
>>> Hi Florian,
>>>
>>> thanks for the info. I've take a look. Seems to be related to the
>>> removed sysdeps/mips/dl-procinfo.c with those undefs at the end:
>>> #undef PROCINFO_DECL
>>> #undef PROCINFO_CLASS
>>>
>>> Bye,
>>> Stefan
>>
>> Okay, we have this chain:
>> - elf/ldconfig.c:
>> #define PROCINFO_CLASS static
>> #include <dl-hwcaps.h>
>> -> elf/dl-hwcaps.h
>> -> elf/dl-tunables.h
>> -> <build>/dl-tunable-list.h
>> -> sysdeps/mips/dl-procinfo.h:
>> -> sysdeps/unix/sysv/linux/mips/ldsodefs.h
>> -> sysdeps/unix/sysv/linux/ldsodefs.h:
>> -> sysdeps/gnu/ldsodefs.h
>> -> sysdeps/mips/ldsodefs.h
>> -> sysdeps/generic/ldsodefs.h:
>> ...
>> #include <dl-procinfo.c>
>> ...
>> # define PROCINFO_DECL
>> # ifndef PROCINFO_CLASS
>> #  define PROCINFO_CLASS EXTERN
>> # endif
>> # include <dl-vdso-setup.c>
>> ...
>>
>> Before my patch, sysdeps/mips/dl-procinfo.c contains those undefs at the
>> end:
>> #undef PROCINFO_DECL
>> #undef PROCINFO_CLASS
>> With my patch, the empty sysdeps/generic/dl-procinfo.c is used.
>>
>> Thus we end up in:
>> static int (*_dl_vdso_...) (...) RELRO;
>> vs before:
>> extern int (*_dl_vdso_...) (...) RELRO;
>>
>> The latter builds fine, while the former produces the "defined but not
>> used" warnings.
>>
>>
>> Thus I will adjust my patch to keep sysdeps/mips/dl-procinfo.c with only
>> something like this:
>> /* Note:
>>    When compiling elf/ldconfig.c, PROCINFO_CLASS is defined to static.
>>    This dl-procinfo.c is included in sysdeps/generic/ldsodefs.h.
>>    Afterwards, if not yet defined, PROCINFO_CLASS is defined to EXTERN
>>    just before dl-vdso-setup.c is included.  A "static" _dl_vdso_xyz
>>    function prototype would lead to gcc warnings/errors: defined but
>>    not used.  */
>> #undef PROCINFO_DECL
>> #undef PROCINFO_CLASS
>>
>>
>> My patch also removes sysdeps/alpha/dl-procinfo.c and
>> sysdeps/csky/dl-procinfo.c with those #undef's at the end. But alpha and
>> csky do not define the vdso HAVE_XYZ_VSYSCALL macros and thus do not end
>> up with those errors.
>> (At the end of dl-vdso-setup.c, PROCINFO_DECL and PROCINFO_CLASS are
>> also undefined)
>>
>> I run build-many-glibcs.py from scratch which lasts some time.
>> Afterwards I'll send a V2 series.
>>
>> Thanks,
>> Stefan
> 
> I've successfully run build-many-glibcs.py from scratch - all PASSed -
> and I send a V2 with the MIPS-fix:
> [V2] elf: Remove platform strings in dl-procinfo.c
> https://sourceware.org/pipermail/libc-alpha/2024-June/157391.html
> 
> Adhemerval has already reviewed the remaining patches. As soon as this
> V2 is also reviewed, I can push the series.
> 
> Thanks,
> Stefan

Adhemerval has also reviewed
[V2] elf: Remove platform strings in dl-procinfo.c

Thus I've committed the series.

Thanks,
Stefan