Right now we have no users of __get_user_unaligned() outside of
arch/* and only 4 users of __put_user_unaligned() outside of arch/*.
All 4 are in compat_sys_getdents64(). For storing
->d_ino and ->d_off in
struct linux_dirent64 {
u64 d_ino;
s64 d_off;
unsigned short d_reclen;
unsigned char d_type;
char d_name[0];
};
in case 32bit userland has weaker alignment requirements for that thing
and passes us a pointer that would've been aligned for 32bit, but not
for 64bit ABI. Which architecture would that be, though?
arm, mips, powerpc, sparc and s390 have that thing 64bit-aligned
in 32bit ABI (both of them in case of mips). And since native getdents()
does *not* maintain more than that when padding an entry, we'd better have
put_user() of 64bit values work for any 64bit-aligned pointer. I hadn't
checked actual cross-compile for tile, but judging by their compat.h they
are not suffering from that kind of braindamage either.
x86 does, indeed, have weaker alignment in 32bit ABI. It also
has __put_user_unaligned defined as __put_user.
Is there any reason to keep those around? As it is, the only places
that need those are m68k and arm binfmt-flat, and these boil down to "can this
CPU flavour do unaligned access?", with "use __get_user/__put_user" and
"use __copy_from_user/__copy_to_user" as outcomes. Nothing more fancy...
