Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932622AbdHWStJ (ORCPT ); Wed, 23 Aug 2017 14:49:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:51280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932459AbdHWStJ (ORCPT ); Wed, 23 Aug 2017 14:49:09 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 65B7F21A29 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=robh@kernel.org MIME-Version: 1.0 In-Reply-To: References: <20170808110305.2748-1-jszhang@marvell.com> <20170823015108.GA18228@kroah.com> <20170823103420.6ffb5ce7@xhacker> From: Rob Herring Date: Wed, 23 Aug 2017 13:48:47 -0500 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] binder: let ANDROID_BINDER_IPC_32BIT be selectable on 32bit ARM To: John Stultz Cc: Jisheng Zhang , Greg KH , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Riley Andrews , devel@driverdev.osuosl.org, lkml , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2450 Lines: 59 On Tue, Aug 22, 2017 at 9:57 PM, John Stultz wrote: > On Tue, Aug 22, 2017 at 7:56 PM, John Stultz wrote: >> On Tue, Aug 22, 2017 at 7:34 PM, Jisheng Zhang wrote: >>> On Tue, 22 Aug 2017 18:51:08 -0700 Greg KH wrote: >>> >>>> On Tue, Aug 08, 2017 at 07:03:05PM +0800, Jisheng Zhang wrote: >>>> > As noted in commit d0bdff0db809 ("staging: Fix build issues with new >>>> > binder API"), we can add back the choice for 32bit ARM "once a 64bit >>>> > __get_user_asm_* implementation is merged." Commit e38361d032f1 ("ARM: >>>> > 8091/2: add get_user() support for 8 byte types") has added the >>>> > support, so it's time to let ANDROID_BINDER_IPC_32BIT be selectable on >>>> > 32bit ARM >>>> >>>> Ok, but: >>>> >>>> > >>>> > Signed-off-by: Jisheng Zhang >>>> > --- >>>> > drivers/android/Kconfig | 2 +- >>>> > 1 file changed, 1 insertion(+), 1 deletion(-) >>>> > >>>> > diff --git a/drivers/android/Kconfig b/drivers/android/Kconfig >>>> > index 832e885349b1..aca5dc30b97b 100644 >>>> > --- a/drivers/android/Kconfig >>>> > +++ b/drivers/android/Kconfig >>>> > @@ -32,7 +32,7 @@ config ANDROID_BINDER_DEVICES >>>> > therefore logically separated from the other devices. >>>> > >>>> > config ANDROID_BINDER_IPC_32BIT >>>> > - bool >>>> > + bool "Use old (Android 4.4 and earlier) 32-bit binder API" >>>> > depends on !64BIT && ANDROID_BINDER_IPC >>>> >>>> You don't actually change the depends line :( >>>> >>>> Please fix up, and test it, and then resend. >>> >>> IHOM, the dependency is correct: 64bit platforms don't support >>> ANDROID_BINDER_IPC_32BIT. What do you think? >> >> I think this indicates the commit message is unclear. >> >> Part of it is that the config is inverted from the description. The >> patch doesn't enable the 32bit legacy binder ABI on 32bit systems, it >> just allows the option to be unselected, so that the 64bit ABI will be >> used on 32bit systems. >> >> Conceptually I don't have an objection to the change (though maybe try >> to rework the commit message), but I don't have anything to actually >> test it on right now, so I'm hesitant to ack it. > > It might also be good to add some detail as to the motivation for this > change? What benefit does it bring to 32bit platforms to use the newer > 64bit ABI? It allows running the same 32-bit userspace build whether the kernel is 64-bit or 32-bit. Rob