From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH v2 05/19] xen: arm: Add and use r/o+raz and w/o+wi helpers Date: Fri, 8 May 2015 11:16:14 +0100 Message-ID: <1431080174.2660.421.camel@citrix.com> References: <1429279300.25195.330.camel@citrix.com> <1429279315-32143-5-git-send-email-ian.campbell@citrix.com> <553BCBF8.4070107@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <553BCBF8.4070107@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: Julien Grall Cc: julien.grall@linaro.org, tim@xen.org, stefano.stabellini@eu.citrix.com, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Sat, 2015-04-25 at 22:16 +0500, Julien Grall wrote: > Hi Ian, > > On 17/04/2015 19:01, Ian Campbell wrote: > > Signed-off-by: Ian Campbell > > --- > > v2: Move last paramter of a handle_ro_raz call to next patch where it > > belongs. > > --- > > xen/arch/arm/traps.c | 52 ++++++++++++++++++++++++++++++++------------------ > > 1 file changed, 33 insertions(+), 19 deletions(-) > > > > diff --git a/xen/arch/arm/traps.c b/xen/arch/arm/traps.c > > index 8b1846a..b54aef6 100644 > > --- a/xen/arch/arm/traps.c > > +++ b/xen/arch/arm/traps.c > > @@ -1587,6 +1587,34 @@ static void handle_raz_wi(struct cpu_user_regs *regs, > > advance_pc(regs, hsr); > > } > > > > +/* Write only + write ignore */ > > [..] > > > +/* Read only + read as zero */ > > I'm not sure if we finished the discussion on those comment on v1 before > you sent the v2. I think we hadn't. > The "+" is very confusing for me because it indicates two parts: write > only and write ignore (same for the read). Both part doesn't really fit > together. Although this helper clearly choose to implement WO as WI > (resp. RO as RAZ). > I think this should be clearer in order to avoid people think this can > be used for RO but with a different value than 0. For v3 I've made the change I proposed in <1429266891.25195.260.camel@citrix.com> Specifically "Write only as write ignore" and "Read only as read as zero" (essentially s/+/as/) Is that clear enough do you think? Ian.