From: Arnd Bergmann <arnd@arndb.de>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"benh@kernel.crashing.org" <benh@kernel.crashing.org>,
"chris@zankel.net" <chris@zankel.net>,
"cmetcalf@tilera.com" <cmetcalf@tilera.com>,
"davem@davemloft.net" <davem@davemloft.net>,
"deller@gmx.de" <deller@gmx.de>,
"dhowells@redhat.com" <dhowells@redhat.com>,
"geert@linux-m68k.org" <geert@linux-m68k.org>,
"heiko.carstens@de.ibm.com" <heiko.carstens@de.ibm.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"jcmvbkbc@gmail.com" <jcmvbkbc@gmail.com>,
"jesper.nilsson@axis.com" <jesper.nilsson@axis.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"monstr@monstr.eu" <monstr@monstr.eu>,
"paulmck@linux.vnet.ibm.com" <paulmck@linux.vnet.ibm.com>,
"rdunlap@infradead.org" <rdunlap@infradead.org>,
"sam@ravnborg.org" <sam@ravnborg.org>
Subject: Re: [PATCH v3 00/17] Cross-architecture definitions of relaxed MMIO accessors
Date: Thu, 25 Sep 2014 21:17:19 +0200 [thread overview]
Message-ID: <201409252117.19754.arnd@arndb.de> (raw)
In-Reply-To: <54243395.902@linaro.org>
On Thursday 25 September 2014, Daniel Thompson wrote:
> > +
> > +#ifndef readq_relaxed
> > +#define readq_relaxed readq
> > +#endif
>
> Not really sure if it matters but this gives a rather surprising
> behaviour to #ifdef readq_relaxed given that readq may not be defined.
>
It was intentional. I could have written this as
#if !defined(readq_relaxed) && defined(readq)
but the effect would be almost the same, and the version I picked looks
simpler. Note that 32-bit architectures could provide readq, it's just
the generic code that doesn't, because most you typically don't get
atomic 64-bit accesses from dereferencing a 64-bit pointer as the
generic readq() function does.
Arnd
WARNING: multiple messages have this Message-ID (diff)
From: Arnd Bergmann <arnd@arndb.de>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"benh@kernel.crashing.org" <benh@kernel.crashing.org>,
"chris@zankel.net" <chris@zankel.net>,
"cmetcalf@tilera.com" <cmetcalf@tilera.com>,
"davem@davemloft.net" <davem@davemloft.net>,
"deller@gmx.de" <deller@gmx.de>,
"dhowells@redhat.com" <dhowells@redhat.com>,
"geert@linux-m68k.org" <geert@linux-m68k.org>,
"heiko.carstens@de.ibm.com" <heiko.carstens@de.ibm.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"jcmvbkbc@gmail.com" <jcmvbkbc@gmail.com>,
"jesper.nilsson@axis.com" <jesper.nilsson@axis.com>,
"mingo@redhat.com" <mingo@redhat.com>,
"monstr@monstr.eu" <monstr@monstr.eu>,
"paulmck@linux.vnet.ibm.com" <paulmck@linux.vnet.ibm.com>,
"rdunlap@infradead.org" <rdunlap@infradead.org>,
"sam@ravnborg.org" <sam@ravnborg.org>,
"schwidefsky@de.ibm.com" <schwidefsky@de.ibm.com>,
"starvik@axis.com" <starvik@axis.com>,
"takata@linux-m32r.org" <takata@linux-m32r.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"tony.luck@intel.com" <tony.luck@intel.com>,
"broonie@linaro.org" <broonie@linaro.org>,
"linux@arm.linux.org.uk" <linux@arm.linux.org.uk>,
"thierry.reding@gmail.com" <thierry.reding@gmail.com>
Subject: Re: [PATCH v3 00/17] Cross-architecture definitions of relaxed MMIO accessors
Date: Thu, 25 Sep 2014 21:17:19 +0200 [thread overview]
Message-ID: <201409252117.19754.arnd@arndb.de> (raw)
Message-ID: <20140925191719.ASK2nF9QmD7cSabk9g4pt-YUA5euh-3kpb3nkEI1eHs@z> (raw)
In-Reply-To: <54243395.902@linaro.org>
On Thursday 25 September 2014, Daniel Thompson wrote:
> > +
> > +#ifndef readq_relaxed
> > +#define readq_relaxed readq
> > +#endif
>
> Not really sure if it matters but this gives a rather surprising
> behaviour to #ifdef readq_relaxed given that readq may not be defined.
>
It was intentional. I could have written this as
#if !defined(readq_relaxed) && defined(readq)
but the effect would be almost the same, and the version I picked looks
simpler. Note that 32-bit architectures could provide readq, it's just
the generic code that doesn't, because most you typically don't get
atomic 64-bit accesses from dereferencing a 64-bit pointer as the
generic readq() function does.
Arnd
next prev parent reply other threads:[~2014-09-25 19:19 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-24 17:17 [PATCH v3 00/17] Cross-architecture definitions of relaxed MMIO accessors Will Deacon
2014-09-24 17:17 ` [PATCH v3 01/17] asm-generic: io: implement relaxed accessor macros as conditional wrappers Will Deacon
2014-09-25 10:32 ` Arnd Bergmann
2014-09-25 10:32 ` Arnd Bergmann
2014-09-25 10:38 ` Will Deacon
2014-09-25 10:38 ` Will Deacon
2014-09-25 10:43 ` Arnd Bergmann
2014-09-25 10:43 ` Arnd Bergmann
2014-09-25 11:44 ` Will Deacon
2014-09-25 11:44 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 02/17] microblaze: io: remove dummy relaxed accessor macros Will Deacon
2014-09-24 17:17 ` [PATCH v3 03/17] s390: io: remove dummy relaxed accessor macros for reads Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 04/17] xtensa: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-25 15:22 ` Max Filippov
2014-09-25 15:22 ` Max Filippov
2014-09-24 17:17 ` [PATCH v3 05/17] frv: io: implement dummy relaxed accessor macros for writes Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 06/17] cris: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 07/17] ia64: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 08/17] m32r: " Will Deacon
2014-09-24 17:17 ` [PATCH v3 09/17] m68k: " Will Deacon
2014-09-25 1:05 ` Greg Ungerer
2014-09-25 9:33 ` Will Deacon
2014-09-25 9:33 ` Will Deacon
2014-09-25 9:51 ` Geert Uytterhoeven
2014-09-25 9:51 ` Geert Uytterhoeven
2014-09-25 10:33 ` Will Deacon
2014-09-25 10:33 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 10/17] mn10300: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 11/17] parisc: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-25 20:00 ` Helge Deller
2014-09-24 17:17 ` [PATCH v3 12/17] powerpc: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 13/17] sparc: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 14/17] tile: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 15/17] x86: " Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-24 17:17 ` [PATCH v3 16/17] documentation: memory-barriers: clarify relaxed io accessor semantics Will Deacon
2014-09-24 17:17 ` [PATCH v3 17/17] asm-generic: io: define relaxed accessor macros unconditionally Will Deacon
2014-09-24 17:17 ` Will Deacon
2014-09-25 10:42 ` [PATCH v3 00/17] Cross-architecture definitions of relaxed MMIO accessors Arnd Bergmann
2014-09-25 13:15 ` Arnd Bergmann
2014-09-25 13:15 ` Arnd Bergmann
2014-09-25 14:55 ` Will Deacon
2014-09-25 14:55 ` Will Deacon
2014-09-25 15:07 ` Arnd Bergmann
2014-09-25 15:07 ` Arnd Bergmann
2014-09-25 15:15 ` Arnd Bergmann
2014-09-25 15:15 ` Arnd Bergmann
2014-09-25 15:24 ` Daniel Thompson
2014-09-25 15:24 ` Daniel Thompson
2014-09-25 19:17 ` Arnd Bergmann [this message]
2014-09-25 19:17 ` Arnd Bergmann
2014-09-25 20:17 ` Geert Uytterhoeven
2014-09-25 20:17 ` Geert Uytterhoeven
2014-09-26 8:40 ` Russell King - ARM Linux
2014-09-26 8:40 ` Russell King - ARM Linux
2014-09-26 9:28 ` Arnd Bergmann
2014-09-26 9:28 ` Arnd Bergmann
2014-09-26 8:05 ` Thierry Reding
2014-09-26 8:05 ` Thierry Reding
2014-09-26 13:39 ` Arnd Bergmann
2014-09-26 13:39 ` Arnd Bergmann
2014-09-26 13:46 ` Russell King - ARM Linux
2014-09-26 13:46 ` Russell King - ARM Linux
2014-09-26 21:36 ` Arnd Bergmann
2014-09-26 21:36 ` Arnd Bergmann
2014-09-29 8:23 ` Thierry Reding
2014-09-29 8:23 ` Thierry Reding
2014-09-29 9:50 ` Arnd Bergmann
2014-09-29 9:50 ` Arnd Bergmann
2014-10-01 15:23 ` Thierry Reding
2014-10-01 15:23 ` Thierry Reding
2014-10-01 18:34 ` Arnd Bergmann
2014-10-01 18:34 ` Arnd Bergmann
2014-09-29 9:25 ` Will Deacon
2014-09-29 9:25 ` Will Deacon
2014-09-29 9:48 ` Arnd Bergmann
2014-09-29 9:48 ` Arnd Bergmann
2014-10-30 16:59 ` Will Deacon
2014-10-30 16:59 ` Will Deacon
2014-10-30 20:04 ` Arnd Bergmann
2014-10-30 20:04 ` Arnd Bergmann
2014-10-31 11:09 ` Thierry Reding
2014-10-31 11:09 ` Thierry Reding
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