Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] drm/amdgpu: fix clang out-of-range warning
To:     Arnd Bergmann <arnd@kernel.org>,
        Alex Deucher <alexander.deucher@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>
Cc:     Arnd Bergmann <arnd@arndb.de>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Evan Quan <evan.quan@amd.com>,
        Hawking Zhang <Hawking.Zhang@amd.com>,
        Huang Rui <ray.huang@amd.com>, shaoyunl <shaoyun.liu@amd.com>,
        Andrey Grodzovsky <andrey.grodzovsky@amd.com>,
        Jack Zhang <Jack.Zhang1@amd.com>,
        amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev
References: <20210927121958.941637-1-arnd@kernel.org>
From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>
Message-ID: <998000b4-993a-1053-e1f2-b716dc32ae9b@amd.com>
Date:   Mon, 27 Sep 2021 14:26:13 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.13.0
In-Reply-To: <20210927121958.941637-1-arnd@kernel.org>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-US
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?WXEyNjkvM094WDdTeVdMV2hheUpMY2JaWVlNTEYwaUFEb1ZSTFZqTGxuMDJp?=
 =?utf-8?B?Rkgvbi9EZ2ptTTZrOHR0NUxwRGx0M0RsSHFZTGo2dkU5bzhOaVZ3YnhMT0tn?=
 =?utf-8?B?Qm1jUmVkK3laOFRsQVF6QlRWR1dIYTRLRnhvQmYxU2NjRFUzM29QWTlCRWJs?=
 =?utf-8?B?Zlc4QVNwY2RCWE81SlFDRVRlWGRYd3d6a3gwRzdnOTVUdXhscE5GVWtadnVt?=
 =?utf-8?B?bjhUWkRlQlRHYmk4YjVUcUcvVVlYUWlFVHNqenk3cUQ4QlBmaWw0UExyM1k0?=
 =?utf-8?B?dFc0QlBPN0ZKOU5xRWtMZUcxejFQaDFUSHkwS2YzTC9HTXhhMFBvWGZPQmNw?=
 =?utf-8?B?aHpxSnBZSVFMNjlaeVlhcVlVL2lGMld6RCtmbGZsdDczbWVNZjAweWsrMGtp?=
 =?utf-8?B?RFRSd3J1eVh1NmJ2R2VjNFUwVGpYdEtlemlDdE0wUHA3QVpmSTdpRVdydzVI?=
 =?utf-8?B?VUw1ZHBWSzVZNlgzcEVDOE41M0gvRUtTbGIwWVBmRnFTaHliRVRYQ3FKcGpr?=
 =?utf-8?B?S29YTFdBK01QdGZ2M0djdThsSm90R3E3ZWx4SWVuUVBhdDI1aUk0U2UrTGFa?=
 =?utf-8?B?U1U1eWtTV3U3WnJRMmNvT2NDVkNQRUZCMS9rVWtNSFdXTzhDVkt4WjVKUXU3?=
 =?utf-8?B?dDNvU2RaL3N4ZVpSR3l2ZndObmtFWEtNbzRQeGFlVEx3RHBtWTFxTWpDT1JP?=
 =?utf-8?B?amlrWTF3YzNQcm9zNy9mTjIyMlExSXkzZzVSYjRxUFE4dmRyT01mSHBFWmRI?=
 =?utf-8?B?emMraGxZVHZZUDQ2U1pWSkVHSzdsdDN6Y0pWam0zSC9GcHVwTkVtVzVqNGtB?=
 =?utf-8?B?bk9yU0tCSmNpMFdJS25rRlAyVjlZNUtnNkdoUzZVS0ZrSDVsc0RkUEFSYkNL?=
 =?utf-8?B?Q3M0VXQ4d1pQR1FiczhjN1NiVm1XK3o1WS96TlZaWXFqdW1MVkhRYkRTSUh6?=
 =?utf-8?B?NXhQZ0U5dEZweEF0blZyOGk0T2NIOUJzNGQ0eXFzaHRuL1lId2tuaUJxdXBu?=
 =?utf-8?B?d3cwc3dSU3pydEM2UzFQbVB0bzFjYklBOE5DVHNnRVNORm41YWY5Z0piQWFY?=
 =?utf-8?B?ODVNRm85MmJjVlZlWW10eTRqRE4yQy9oV2dHNW1ZRVVCZW1iYmpyRUdrM1BC?=
 =?utf-8?B?ZTg5TzNreGEyYVU2STZQZlFZcit1QlRlREVwb0pWSGRmWkVJZTU3cXZ3b0hh?=
 =?utf-8?B?TGNmeVduNFVLbTY5R1dHNEtWTEd3MjVJUGJtaFJPWHFwSjM4SHNlL3FORjkz?=
 =?utf-8?B?SmZXSUtmV0VCazdnd29YSFM3VS8zSFZtVGprQVZEc2pjb1hQQy94RXBQem9B?=
 =?utf-8?B?VUkxYjVQZGFPM25wdFJtOHV5K0NieFhRSTczMjgyV0FScUxrYTVXSTIrNUpB?=
 =?utf-8?B?R1ZRN3VHY0dQOFVpNGIwa2N3bUxaak9UYklCRnpPNTlMYkdtYWsyNzVXYjBD?=
 =?utf-8?B?ME52cEpBYkN3Mlk4UkJsUFl2eVRtalBsMFhqbWtLL3JkbkZ5Y0Q5OFhkSXN3?=
 =?utf-8?B?Z25WaUdNK2ZVV2xEQXh5c0h4SlJib3NqN3Y1S3huZFdsRzFxWW1Cd2VmTlN5?=
 =?utf-8?B?alVXUm55WWpVSndOTDZuNzJhYURmaytxZzUxYkZHeUJ1TG9WR0huUnZaU2Zn?=
 =?utf-8?B?UHEwVlBtQUpiRldKd1djMXlBNTczbEdjZnlPOTU4elQzb0lXNDdHTU42MU5r?=
 =?utf-8?B?VCtER0tPNExnbnVLaHZ1MjFtYU5tS0d1akN4SElNbmRyV0lQTGgxdUN6T2cv?=
 =?utf-8?Q?7l+pCbWORe9aUmvaELyDRD71MfQy9xIo57m4YbG?=
X-OriginatorOrg: amd.com
X-MS-Exchange-CrossTenant-Network-Message-Id: 84960288-c3c4-4ab8-4a08-08d981b20463
X-MS-Exchange-CrossTenant-AuthSource: MWHPR1201MB0192.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 27 Sep 2021 12:26:22.9252
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: DKlxj6UngwsKJP0rQETm6WSbFVr9dP9AWRpPue67c7tPZIUUAoQvtxkNKCy9HuWB
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MWHPR12MB1453
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

In general that change looks good. But what configuration is that?

Background is that it doesn't make much sense to compile the amdgpu 
driver on systems where resource_size_t is only 32bit.

Christian.

Am 27.09.21 um 14:19 schrieb Arnd Bergmann:
> From: Arnd Bergmann <arnd@arndb.de>
>
> clang-14 points out that comparing an 'unsigned int' against a large
> 64-bit constantn is pointless:
>
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c:1206:18: error: result of comparison of constant 4294967296 with expression of type 'resource_size_t' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
>                      res->start > 0x100000000ull)
>
> Rephrase the comparison using the upper_32_bits() macro, which should
> keep it legible while avoiding the warning.
>
> Fixes: 31b8adab3247 ("drm/amdgpu: require a root bus window above 4GB for BAR resize")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index ab3794c42d36..741a55031ca1 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -1203,7 +1203,7 @@ int amdgpu_device_resize_fb_bar(struct amdgpu_device *adev)
>   
>   	pci_bus_for_each_resource(root, res, i) {
>   		if (res && res->flags & (IORESOURCE_MEM | IORESOURCE_MEM_64) &&
> -		    res->start > 0x100000000ull)
> +		    upper_32_bits(res->start) != 0)
>   			break;
>   	}
>