From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 References: <20200228221131.hvtpjrjm42ocbxjo@csclub.uwaterloo.ca> In-Reply-To: <20200228221131.hvtpjrjm42ocbxjo@csclub.uwaterloo.ca> From: Richard Weinberger Date: Fri, 28 Feb 2020 23:16:41 +0100 Message-ID: Subject: Re: 32bit compat mode for arm64 Content-Type: text/plain; charset="UTF-8" List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Lennart Sorensen Cc: xenomai@xenomai.org On Fri, Feb 28, 2020 at 11:11 PM Lennart Sorensen wrote: > > On Fri, Feb 28, 2020 at 10:01:04PM +0100, Richard Weinberger via Xenomai wrote: > > I noticed that running 32bit arm EABI xenomai userspace is currently > > not possible > > on arm64 kernels. > > > > From a quick look I see the following tasks to make it happen: > > - syscall gate adaptations for cobalt arm32 syscalls (they are > > different from regular arm EABI) > > - teach ipipe_root_nr_syscalls() on arm64 about __NR_compat_syscalls > > - Don't use XENOMAI_ABI_REV for compat userspace on arm64 > > - Implement a syscall32-table.h (for COBALT_SYSCALL32emu_DECL() and friends) > > > > Is this something which will be supported sooner or later? > > ...or is there a massive show-stopper I didn't notice so far? > > Even x86 doesn't allow 32 bit userspace xenomai to run on a 64 bit kernel. > I suspect the use case is just so insignificant that noone wants to > bother working on such support. Huh? I currently do so... It was broken but got fixed. -- Thanks, //richard