From: Julien Grall <julien@xen.org>
To: Jan Beulich <jbeulich@suse.com>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Ian Jackson" <iwj@xenproject.org>,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Subject: Re: [PATCH 02/23] lib: move 64-bit div/mod compiler helpers
Date: Wed, 7 Apr 2021 15:06:15 +0100 [thread overview]
Message-ID: <42f74b93-1ef2-a3c5-6718-01efd4ffce2c@xen.org> (raw)
In-Reply-To: <75299b2a-9610-57fb-95a3-c49d926af54b@suse.com>
On 07/04/2021 09:33, Jan Beulich wrote:
> On 06.04.2021 21:34, Julien Grall wrote:
>> Hi Jan,
>>
>> On 01/04/2021 16:23, Jan Beulich wrote:
>>> On 01.04.2021 16:56, Julien Grall wrote:
>>>> On 01/04/2021 11:19, Jan Beulich wrote:
>>>>> --- a/xen/common/lib.c
>>>>> +++ b/xen/lib/divmod.c
>>>>> @@ -40,7 +40,6 @@
>>>>> * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
>>>>> * SUCH DAMAGE.
>>>>> */
>>>>> -#if BITS_PER_LONG == 32
>>>>
>>>> In theory BITS_PER_LONG == 32 is not quite the same as 32-bit arch. Can
>>>> you clarify whether this code is necessary on 64-bit arch where long is
>>>> only 32-bit.
>>>
>>> Likely the compiler can get away without invoking these helpers, so
>>> the code would remain unused. I'm uncertain whether CONFIG_64BIT
>>> ought to be set for such an architecture, as we assume sizeof(long)
>>> == sizeof(void*), and hence pointers would then need to be 32-bit
>>> as well there.
>>
>> This is a fair point. Would you mind to add a sentence explaining that
>> in the commit message?
>
> I've added
>
> "Note that we imply "32-bit arch" to be the same as BITS_PER_LONG == 32,
> i.e. we aren't (not just here) prepared to have a 64-bit arch with
> BITS_PER_LONG == 32. Yet even if we supported such, likely the compiler
> would get away there without invoking these helpers, so the code would
> remain unused in practice."
Sounds fine to me.
>
>> With that:
>>
>> Acked-by: Julien Grall <jgrall@amazon.com>
>
> Thanks. Any chance to also get an ack on patch 1, so at least these two
> (or three, seeing that you also did ack patch 3) could go in before my
> re-posting of the series to add the one line commit message additions
> that you did ask for on all the str* and mem* patches? (Alternatively I
> could take the time and re-order the two.)
I didn't ack #1 because I am not very familiar with the x86 constraints.
If anyone with x86 background (maybe Roger?) is willing to review it,
then I would be happy to give my ack.
Cheers,
--
Julien Grall
next prev parent reply other threads:[~2021-04-07 14:06 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 10:14 [PATCH 00/23] further population of xen/lib/ Jan Beulich
2021-04-01 10:19 ` [PATCH 01/23] lib: move muldiv64() Jan Beulich
2021-04-15 10:00 ` Ping (x86): " Jan Beulich
2021-04-15 12:46 ` Roger Pau Monné
2021-04-01 10:19 ` [PATCH 02/23] lib: move 64-bit div/mod compiler helpers Jan Beulich
2021-04-01 14:56 ` Julien Grall
2021-04-01 15:23 ` Jan Beulich
2021-04-06 19:34 ` Julien Grall
2021-04-07 8:33 ` Jan Beulich
2021-04-07 14:06 ` Julien Grall [this message]
2021-04-01 10:20 ` [PATCH 03/23] string: drop redundant declarations Jan Beulich
2021-04-01 14:59 ` Julien Grall
2021-04-01 10:20 ` [PATCH 04/23] lib: move memset() Jan Beulich
2021-04-01 10:21 ` [PATCH 05/23] lib: move memcpy() Jan Beulich
2021-04-01 10:21 ` [PATCH 06/23] lib: move memmove() Jan Beulich
2021-04-01 10:22 ` [PATCH 07/23] lib: move memcmp() Jan Beulich
2021-04-01 10:22 ` [PATCH 08/23] lib: move memchr() Jan Beulich
2021-04-01 10:23 ` [PATCH 09/23] lib: move memchr_inv() Jan Beulich
2021-04-01 10:23 ` [PATCH 10/23] lib: move strlen() Jan Beulich
2021-04-01 10:23 ` [PATCH 11/23] lib: move strnlen() Jan Beulich
2021-04-01 10:24 ` [PATCH 12/23] lib: move strcmp() Jan Beulich
2021-04-01 10:25 ` [PATCH 13/23] lib: move strncmp() Jan Beulich
2021-04-01 10:25 ` [PATCH 14/23] lib: move strlcpy() Jan Beulich
2021-04-01 10:25 ` [PATCH 15/23] lib: move strlcat() Jan Beulich
2021-04-01 10:25 ` [PATCH 16/23] lib: move strchr() Jan Beulich
2021-04-01 10:26 ` [PATCH 17/23] lib: move strrchr() Jan Beulich
2021-04-01 10:26 ` [PATCH 18/23] lib: move strstr() Jan Beulich
2021-04-01 10:26 ` [PATCH 19/23] lib: move strcasecmp() Jan Beulich
2021-04-01 10:27 ` [PATCH 20/23] lib: move/rename strnicmp() to strncasecmp() Jan Beulich
2021-04-01 10:27 ` [PATCH 21/23] lib: move strspn() Jan Beulich
2021-04-01 10:28 ` [PATCH 22/23] lib: move strpbrk() Jan Beulich
2021-04-01 10:28 ` [PATCH 23/23] lib: move strsep() Jan Beulich
2021-04-01 11:54 ` [PATCH 00/23] further population of xen/lib/ Julien Grall
2021-04-01 13:43 ` Jan Beulich
2021-04-01 14:04 ` Julien Grall
2021-04-01 14:27 ` Jan Beulich
2021-04-01 14:55 ` Julien Grall
2021-04-01 15:25 ` Jan Beulich
2021-04-01 15:32 ` Julien Grall
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