From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH v2 for 4.5] arm32: fix build after 063188f4b3 Date: Tue, 14 Oct 2014 14:06:29 +0100 Message-ID: <543D1FD5.6080002@linaro.org> References: <1413214141-370-1-git-send-email-julien.grall@linaro.org> <1413278157.1497.13.camel@citrix.com> <543D1A86.8010001@linaro.org> <1413291439.10417.48.camel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1Xe1oE-0000pX-3t for xen-devel@lists.xenproject.org; Tue, 14 Oct 2014 13:06:38 +0000 Received: by mail-wi0-f175.google.com with SMTP id d1so10078841wiv.2 for ; Tue, 14 Oct 2014 06:06:36 -0700 (PDT) In-Reply-To: <1413291439.10417.48.camel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: xen-devel@lists.xenproject.org, tim@xen.org, Jan Beulich , stefano.stabellini@citrix.com List-Id: xen-devel@lists.xenproject.org On 10/14/2014 01:57 PM, Ian Campbell wrote: > On Tue, 2014-10-14 at 13:43 +0100, Julien Grall wrote: >> On 10/14/2014 10:15 AM, Ian Campbell wrote: >>> On Mon, 2014-10-13 at 16:29 +0100, Julien Grall wrote: >>> >>>> +GLOBAL(do_smc) >>> >>>> +GLOBAL(do_smc) >>> >>> These should both be ENTRY. >> >> Why? Is it because GLOBAL should be used for variable and ENTRY for >> function? > > Exactly. The practical difference is that ENTRY makes sure the code > entry point is suitably aligned, but semantically ENTRY is the correct > name. Thanks for the explanation. So arm*/debug.S are buggy. I will send a patch to replace GLOBAL by ENTRY. >>>> +int do_smc(register_t function_id, ...); >>> >>> Are you sure that the variadic function calling convention is the same >>> as for a regular function call? I'm not entirely clear having read >>> AAPCS, it says they are marshalled according to "the standard base". >> >> All the parameters fits in a register, so the compiler will effectively >> use the first registers to pass arguments. > > Does it? Even with variadic functions? It's not unheard of for an ABI to > fallback to pushing things onto the stack for such cases, since it works > out far easier in stdargs.h. You are right, it looks like it's compiler depend how variadic function will be called. Regards, -- Julien Grall