From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 14 May 2018 22:57:44 +0200 From: Dominik Brodowski To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, dave.martin@arm.com, james.morse@arm.com, linux-fsdevel@vger.kernel.org, marc.zyngier@arm.com, viro@zeniv.linux.org.uk, will.deacon@arm.com Subject: Re: [PATCH 18/18] arm64: implement syscall wrappers Message-ID: <20180514205744.GC26773@light.dominikbrodowski.net> References: <20180514094640.27569-1-mark.rutland@arm.com> <20180514094640.27569-19-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180514094640.27569-19-mark.rutland@arm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: On Mon, May 14, 2018 at 10:46:40AM +0100, Mark Rutland wrote: > Note that we play games with sys_ni_syscall(). It can't be defined with > SYSCALL_DEFINE0() because we must avoid the possibility of error > injection. Additionally, there are a couple of locations where we need > to call it from C code, and we don't (currently) have a > ksys_ni_syscall(). While it has no wrapper, passing in a redundant > pt_regs pointer is benign per the AAPCS. > > When ARCH_HAS_SYSCALL_WRAPPER is selected, no prototype is define for > sys_ni_syscall(). Since we need to treat it differently for in-kernel > calls and the syscall tables, the prototype is defined as-required. > Largely the wrappers are largely the same as their x86 counterparts, but That's one "Largely" too much. > simplified as we don't have a variety of compat calling conventions that > require separate stubs. Unlike x86, we have some zero-argument compat > syscalls, and must define COMPAT_SYSCALL_DEFINE0(). ... for consistent naming, or is there another reason for that? This patch looks good in any case. Thanks, Dominik