From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932574AbeEWL1r (ORCPT ); Wed, 23 May 2018 07:27:47 -0400 Received: from mail-wr0-f193.google.com ([209.85.128.193]:35442 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754503AbeEWL1q (ORCPT ); Wed, 23 May 2018 07:27:46 -0400 X-Google-Smtp-Source: AB8JxZp5FL76zJ8Judh1/gIyZ/4pNwnYmayR2kxn5BcTnRt6ucmxsh4RbZLiqjH8o9mQUCCZ4NCjwg== Subject: Re: [PATCH] drm/xen-front: fix pointer casts To: Juergen Gross , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, daniel.vetter@intel.com, boris.ostrovsky@oracle.com Cc: Oleksandr Andrushchenko References: <20180521073912.13510-1-andr2000@gmail.com> <11421e59-3219-b9df-7869-0b249041125b@suse.com> From: Oleksandr Andrushchenko Message-ID: <78259eca-6321-883b-7c1b-8443e24662ad@gmail.com> Date: Wed, 23 May 2018 14:27:43 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <11421e59-3219-b9df-7869-0b249041125b@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/23/2018 02:06 PM, Juergen Gross wrote: > On 23/05/18 12:00, Oleksandr Andrushchenko wrote: >> On 05/23/2018 12:19 PM, Juergen Gross wrote: >>> On 21/05/18 09:39, Oleksandr Andrushchenko wrote: >>>> From: Oleksandr Andrushchenko >>>> >>>> Building for a 32-bit target results in warnings from casting >>>> between a 32-bit pointer and a 64-bit integer. Fix the warnings >>>> by casting those pointers to uintptr_t first. >>>> >>>> Signed-off-by: Oleksandr Andrushchenko >>>> >>>> --- >>>>   drivers/gpu/drm/xen/xen_drm_front.h       | 4 ++-- >>>>   drivers/gpu/drm/xen/xen_drm_front_shbuf.c | 2 +- >>>>   2 files changed, 3 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/drivers/gpu/drm/xen/xen_drm_front.h >>>> b/drivers/gpu/drm/xen/xen_drm_front.h >>>> index 2c2479b571ae..8e15dbebc4ba 100644 >>>> --- a/drivers/gpu/drm/xen/xen_drm_front.h >>>> +++ b/drivers/gpu/drm/xen/xen_drm_front.h >>>> @@ -126,12 +126,12 @@ struct xen_drm_front_drm_info { >>>>     static inline u64 xen_drm_front_fb_to_cookie(struct >>>> drm_framebuffer *fb) >>>>   { >>>> -    return (u64)fb; >>>> +    return (u64)(uintptr_t)fb; >>> Do you really still need the cast to u64? >> Indeed, I can remove (u64) now, thank you >>>>   } >>>>     static inline u64 xen_drm_front_dbuf_to_cookie(struct >>>> drm_gem_object *gem_obj) >>>>   { >>>> -    return (u64)gem_obj; >>>> +    return (u64)(uintptr_t)gem_obj; >>>>   } >>>>     int xen_drm_front_mode_set(struct xen_drm_front_drm_pipeline >>>> *pipeline, >>>> diff --git a/drivers/gpu/drm/xen/xen_drm_front_shbuf.c >>>> b/drivers/gpu/drm/xen/xen_drm_front_shbuf.c >>>> index 8099cb343ae3..47fc93847765 100644 >>>> --- a/drivers/gpu/drm/xen/xen_drm_front_shbuf.c >>>> +++ b/drivers/gpu/drm/xen/xen_drm_front_shbuf.c >>>> @@ -122,7 +122,7 @@ static void guest_calc_num_grefs(struct >>>> xen_drm_front_shbuf *buf) >>>>   } >>>>     #define xen_page_to_vaddr(page) \ >>>> -        ((phys_addr_t)pfn_to_kaddr(page_to_xen_pfn(page))) >>>> +        ((phys_addr_t)(uintptr_t)pfn_to_kaddr(page_to_xen_pfn(page))) >>> phys_addr_t for a virtual address? >> This is because the resulting value is then passed to gnttab_set_map_op/ >> gnttab_set_unmap_op which expects host address to be passed as >> phys_addr_t addr :( > Okay, but this means the compiler should do the necessary cast when > you drop the cast to phys_addr_t in xen_page_to_vaddr(), as the cast > to uintptr_t is already producing an unsigned integer value which can > easily be promoted to more bits, right? Right, so I can safely use:  #define xen_page_to_vaddr(page) \ - ((phys_addr_t)(uintptr_t)pfn_to_kaddr(page_to_xen_pfn(page))) +               ((uintptr_t)pfn_to_kaddr(page_to_xen_pfn(page))) > > Juergen Thank you for your time and comments, Oleksandr