[aarch64] question about user.h, ucontext.h, procfs.h

[Szabolcs Nagy]

some questions about aarch64 headers:

(1) 32bit greg_t in ucontext.h

i noticed that sysdeps/unix/sysv/linux/aarch64/sys/ucontext.h
defines greg_t as

  typedef int greg_t;

which seems wrong (i'd expect unsigned long and that's how
elf_greg_t is defined).

other archs use greg_t in the definition of mcontext_t, but
aarch64 gets that from the kernel headers (asm/sigcontext.h)

is greg_t used outside of libc?
can i fix it to have more reasonable definition?
is it ok to depend on linux headers in ucontext.h?

(2) 16bit uid, gid in procfs.h

aarch64 elf_prpsinfo struct has

  unsigned short int pr_uid;
  unsigned short int pr_gid;

members, which seems wrong (i'd expect unsigned int like in
the kernel linux/elfcore.h)

the procfs.h header seems to be something that should be
only used by debuggers which probably rely on kernel headers
or define their own instead of using libc headers.
is this correct?
can i fix this?
should this header be removed completely?

(3) __uint128_t in user.h

aarch64 user_fpsimd_struct has

  __uint128_t vregs[32];

member to represent the 128bit floating point registers

is it ok to expose __uint128_t in public headers?

thanks