On Mon, Apr 3, 2023 at 2:09 AM Samuel Thibault <samuel.thiba...@gnu.org> wrote: > Sergey Bugaev, le dim. 19 mars 2023 18:09:56 +0300, a ecrit: > > While we could/should implement MAP_32BIT for the Hurd port by setting > > all the high bits of mask in a vm_map () call, neither MAP_32BIT nor > > glibc.cpu.prefer_map_32bit_exec exist on the Hurd as of now. Compile > > this code out to fix build failures. > > Rather use defined(MAP_32BIT)? That way it will nicely work for BSD > ports as well, and when hurd eventually supports MAP_32BIT.
Not really. What breaks compilation here is not missing MAP_32BIT, but rather the undefined set_prefer_map_32bit_exec tunable. It is defined declaratively in sysdeps/unix/sysv/linux/x86_64/64/dl-tunables.list (see commit 317f1c0a8a71a862b1e600ff5386b08e02cf4b95); so as-is, it really is x86_64 Linux specific. Is there some way to check if a specific tunable is defined, like #if HAVE_TUNABLE (prefer_map_32bit_exec)? AFAICS the generated dl-tunable-list.h defines the C enum members, but not any checkable preprocessor macros. Alternatively: maybe this part of cpu-features.c should be moved into sysdeps/unix/sysv/linux/x86_64/64/cpu-features.c and #include_next the common cpu-features.c? Sergey
