From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joseph Myers Subject: Re: Can we drop upstream Linux x32 support? Date: Wed, 12 Dec 2018 18:14:00 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: tg@mirbsd.de, Andy Lutomirski , Linus Torvalds , the arch/x86 maintainers , Linux Kernel Mailing List , Linux API , "H. Peter Anvin" , Peter Zijlstra , Borislav Petkov , Florian Weimer , vapier@gentoo.org, "H.J. Lu" , Rich Felker , x32@buildd.debian.org, Will Deacon , Catalin Marinas List-Id: linux-api@vger.kernel.org On Wed, 12 Dec 2018, Arnd Bergmann wrote: > > MIPS had o32, n32, n64 since like forever. > > o32 and n32 are practically the same, the only difference on the > syscall ABI that I can see are the actual syscall numbers, and > the 'struct sigcontext' definition. And for syscalls that have 64-bit arguments, n32 generally passes those in a single register (like n64), not pairs of registers (like o32). But, yes, userspace structure layout for n32 is generally much closer to o32 than to n64. -- Joseph S. Myers joseph@codesourcery.com