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, 08 Oct 2013 12:10:12 +0800 [thread overview]
Message-ID: <525385A4.5050200@asianux.com> (raw)
In-Reply-To: <524F594B.1070106@asianux.com>
Excluding current discussion, the 2 patches (patch 1/2, patch 2/2) for
arm are both OK?
Thanks.
On 10/05/2013 08:11 AM, Chen Gang wrote:
> On 10/05/2013 07:55 AM, Chen Gang wrote:
>> On 10/04/2013 11:42 PM, Will Deacon wrote:
>>> On Fri, Oct 04, 2013 at 04:37:42PM +0100, Will Deacon wrote:
>>>> On Fri, Oct 04, 2013 at 10:51:56AM +0100, Chen Gang wrote:
>>>>> On 10/04/2013 12:32 AM, Will Deacon wrote:
>>>>>> The problem with arm64 is that we're using *unsigned long* for 32-bit
>>>>>> clear_mask, which is definitely wrong because it's 64-bit (another patch to
>>>>>> fix this!).
>>>>>>
>>>>>
>>>>> At least, that is not a bug.
>>>>
>>>> Sure it is. What if the adjacent 32-bit value was being accessed by another
>>>> CPU under a spinlock?
>>>
>>> (Oh, ok, that would still work on arm because of the way the exclusive
>>> monitor is implemented, but we shouldn't rely on that).
>>>
>>
>> Hmm... in my opinion, we need divide atomic_*_mask() into 32-bit and
>> 64-bit versions. We already have demands to only use 32-bit value to
>> express mask (can save size), and may have demands to use 64-bit too.
>>
>> If so, can easily standard all atomic_*_mask() which are in asm-generic
>> and various architectures: use atomic_*_mask() for 32-bit mask, and use
>> atomic64_*_mask() for 64-bit mask (can delayed before get real demands).
>>
>> Since it is about API, so it is related with asm-generic and all other
>> architectures interfaces, it is better to consider about them firstly
>> before the fix under arm64.
>>
>>
>> And also, excuse me, I am not quite familiar with "exclusive monitor",
>> could you please provide more details about it?
>>
>
> If in arm64 with allmodconfig, we only need atomic_*_mask() for 32-bit
> mask, don't need 64-bit, we can use 'unsigned int' instead of 'unsigned
> long' (need not consider about asm-generic and other architectures).
>
>
>
>>
>>> Will
>>>
>>>
>>
>>
>> Thanks.
>>
>
>
--
Chen Gang
next prev parent reply other threads:[~2013-10-08 4:10 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
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 [this message]
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
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