From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] ARM: include: asm: use 'long long' instead of 'u64' within atomic.h
Date: Thu, 26 Sep 2013 11:04:23 +0100 [thread overview]
Message-ID: <20130926100422.GE2855@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <5243953E.6010405@asianux.com>
On Thu, Sep 26, 2013 at 03:00:30AM +0100, Chen Gang wrote:
> On 09/26/2013 12:07 AM, Will Deacon wrote:
> > On Wed, Sep 25, 2013 at 03:25:19AM +0100, Chen Gang wrote:
> >> atomic* value is signed value, and atomic* functions need also process
> >> signed value (parameter value, and return value), so 32-bit arm need
> >> use 'long long' instead of 'u64'.
> >>
> >> After replacement, it will also fix a bug for atomic64_add_negative():
> >> "u64 is never less than 0".
> >>
> >> The modifications are:
> >>
> >> in vim, use "1,% s/\<u64\>/long long/g" command.
> >> remove '__aligned(8)' which is useless for 64-bit.
> >> be sure of 80 column limitation after replacement.
> >>
> >>
> >> Signed-off-by: Chen Gang <gang.chen@asianux.com>
> >
> > Looks better to me, thanks. While you're here, we could also replace the use
> > of `unsigned long' with `int' for the 32-bit atomics, then the whole header
> > is consistent with the generic types.
> >
> > Will
> >
> >
>
> Hmm... at least, it seems we can let "use 'int' for 32-bit atomics" in
> another patch.
Sure, it can be a follow-up to this one.
> Firstly, this 'fix' is not belong to API, and either, it has no related
> 'standard' 'demo' in "asm-generic/" (it is architecture independent, so
> no related inline assembly code).
I was simply going by the types of atomic_t and atomic64_t, which are both
constructed using signed types.
> After a random check, another 3 architectures (maybe more) are also may
> using 'unsigned long': "arm64/include/asm/atomic.h",
> "sh/include/asm/atomic-llsc.h", and "xtensa/include/asm/atomic.h".
>
> And as far as I know, for a register related variable, 'unsigned long'
> is also a common using way for both 32-bit and 64-bit (at least, it is a
> simple way to prevent issues).
Maybe, but atomic_t is always 32-bit and atomic64_t is always 64-bit, so I
don't think unsigned long buys you anything with regards to sizing.
Will
next prev parent reply other threads:[~2013-09-26 10:04 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 [this message]
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
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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