From: gang.chen@asianux.com (Chen Gang)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] ARM: include: asm: use 'int' instead of 'unsigned long' for normal register variables within atomic.h
Date: Tue, 01 Oct 2013 20:03:44 +0800 [thread overview]
Message-ID: <524ABA20.6060106@asianux.com> (raw)
In-Reply-To: <20131001090119.GA17629@mudshark.cambridge.arm.com>
On 10/01/2013 05:01 PM, Will Deacon wrote:
> On Tue, Oct 01, 2013 at 03:05:27AM +0100, Chen Gang wrote:
>> On 10/01/2013 12:11 AM, Will Deacon wrote:
>>> On Sun, Sep 29, 2013 at 04:52:28AM +0100, Chen Gang wrote:
>>>> "arc/arm" will be never on 64-bit, it is mainly on 32-bit (may also can
>>>> be on 16-bit).
>>>>
>>>> So better to use 'int' instead of 'unsigned long' for normal register
>>>> variable (on 16-bit, 'int' is allowed to be 16-bit, so historically,
>>>> often use 'int' for normal register variables).
>>>
>>> This commit message doesn't make a blind bit of sense! arch/arm/ is a 32-bit
>>> architecture in the sense that int will always be 32-bit there. This patch
>>> is just a cosmetic change, bringing our atomic_t manipulation code inline
>>> with the atomic_t type definition.
>>>
>>
>> OK, thanks. That means: "arm means arm 32-bit, arm64 means arm 64-bit.
>> The current Linux kernel main line does not support arm 16-bit".
>>
>> Since "bringing our atomic_t ... with the atomic_t type definition", can
>> we use 'atomic_t" instead of 'unsigned long'?
>>
>> And can we use 'atomic64_t" instead of 'unsigned long' in atomic64_*()?
>
> That's probably a bit dodgy, since they are typedefs to compound types
> which, if ever extended, would fall to bits if we tried to pack them into a
> single register.
>
Excuse me, my English is not quite well, I guess your meaning is: "in
'atomic.h', for arm/arm64, let register variables type equal to related
atomic type: use 64-bit type if 'atomic64_t', 32-bit type if 'atomic_t'.
If what I guess is correct, please continue reading, or please help
repeat again (not need reading below contents), thanks.
Can we say: "under arm, using 'unsigned long' for register related
variables in atomic64_*() is not suitable (although not a bug), need use
'long long' (which is 'atomic64_t' under arm) instead of"?
And under arm64, can we use 'int' (which is 'atomic_t' under 64-bit arm)
instead of 'unsigned long' for register related variables in atomic_*()?
I feel, if both of them above are correct, your idea sounds reasonable,
or it seems your idea is a little complex (at least, keeping original
implementation no touch is still not a bad idea).
> Will
>
>
Thanks.
--
Chen Gang
next prev parent reply other threads:[~2013-10-01 12:03 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-21 11:06 [PATCH] ARM: include: asm: atomic.h: use type cast 's64' for the return value of atomic64_add_return() Chen Gang
2013-09-24 9:30 ` Will Deacon
2013-09-24 10:27 ` Russell King - ARM Linux
2013-09-24 10:37 ` Chen Gang
2013-09-24 10:30 ` Chen Gang
2013-09-25 2:25 ` [PATCH v2] ARM: include: asm: use 'long long' instead of 'u64' within atomic.h Chen Gang
2013-09-25 16:07 ` Will Deacon
2013-09-26 2:00 ` Chen Gang
2013-09-26 10:04 ` Will Deacon
2013-09-26 11:03 ` Chen Gang
2013-09-27 11:06 ` Will Deacon
2013-09-27 11:36 ` Chen Gang
2013-09-29 3:43 ` [PATCH 0/2] ARM: include: asm: change functions' and variables' types in atomic.h Chen Gang
2013-09-29 3:43 ` [PATCH 1/2] ARM: include: asm: use 'long long' instead of 'u64' within atomic.h Chen Gang
2013-09-29 3:52 ` [PATCH 2/2] ARM: include: asm: use 'int' instead of 'unsigned long' for normal register variables " Chen Gang
2013-09-30 16:11 ` Will Deacon
2013-10-01 2:05 ` Chen Gang
2013-10-01 9:01 ` Will Deacon
2013-10-01 12:03 ` Chen Gang [this message]
2013-10-02 10:41 ` Will Deacon
2013-10-02 15:19 ` Chen Gang
2013-10-03 10:05 ` Chen Gang
2013-10-03 16:32 ` Will Deacon
2013-10-04 9:51 ` Chen Gang
2013-10-04 15:37 ` Will Deacon
2013-10-04 15:42 ` Will Deacon
2013-10-04 23:55 ` Chen Gang
2013-10-05 0:11 ` Chen Gang
2013-10-08 4:10 ` Chen Gang
2013-10-08 10:34 ` Will Deacon
2013-10-08 10:56 ` [PATCH v2 0/2] ARM: include: asm: change functions' and variables' types in atomic.h Chen Gang
2013-10-08 10:57 ` [PATCH v2 1/2] ARM: include: asm: use 'long long' instead of 'u64' within atomic.h Chen Gang
2013-10-08 10:59 ` [PATCH v2 2/2] ARM: include: asm: use 'int' instead of 'unsigned long' for 'oldval' in atomic_cmpxchg() Chen Gang
2013-10-09 10:48 ` Will Deacon
2013-10-10 0:56 ` Chen Gang
2013-10-09 10:46 ` [PATCH v2 1/2] ARM: include: asm: use 'long long' instead of 'u64' within atomic.h Will Deacon
2013-10-08 11:00 ` [PATCH 2/2] ARM: include: asm: use 'int' instead of 'unsigned long' for normal register variables " Chen Gang
2013-10-08 10:33 ` Will Deacon
2013-10-08 11:29 ` Chen Gang
2013-10-08 17:49 ` Will Deacon
2013-10-09 0:18 ` Chen Gang
2013-10-09 1:22 ` Chen Gang
2013-09-30 16:07 ` [PATCH 1/2] ARM: include: asm: use 'long long' instead of 'u64' " Will Deacon
2013-10-01 2:09 ` Chen Gang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=524ABA20.6060106@asianux.com \
--to=gang.chen@asianux.com \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.