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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Nick Piggin <npiggin@suse.de>
Cc: linuxppc-dev@ozlabs.org, paulus@samba.org
Subject: Re: [patch 1/2] powerpc: rmb fix
Date: Wed, 21 May 2008 11:27:03 -0400	[thread overview]
Message-ID: <1211383623.8297.197.camel@pasglop> (raw)
In-Reply-To: <20080521141056.GC8897@wotan.suse.de>


On Wed, 2008-05-21 at 16:10 +0200, Nick Piggin wrote:
> Hi,
> 
> I'm sure I've sent these patches before, but I can't remember why they
> weren't merged. They still seem obviously correct to me.

We should already do all that's needed in our IO accessors no ?

> --
> 
> lwsync is explicitly defined not to have any effect on the ordering of
> accesses to device memory, so it cannot be used for rmb(). sync appears
> to be the only barrier which fits the bill.
> 
> Signed-off-by: Nick Piggin <npiggin@suse.de>
> ---
> Index: linux-2.6/include/asm-powerpc/system.h
> ===================================================================
> --- linux-2.6.orig/include/asm-powerpc/system.h
> +++ linux-2.6/include/asm-powerpc/system.h
> @@ -34,7 +34,7 @@
>   * SMP since it is only used to order updates to system memory.
>   */
>  #define mb()   __asm__ __volatile__ ("sync" : : : "memory")
> -#define rmb()  __asm__ __volatile__ (__stringify(LWSYNC) : : : "memory")
> +#define rmb()  __asm__ __volatile__ ("sync" : : : "memory")
>  #define wmb()  __asm__ __volatile__ ("sync" : : : "memory")
>  #define read_barrier_depends()  do { } while(0)
>  
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev

  parent reply	other threads:[~2008-05-21 15:27 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-21 14:10 [patch 1/2] powerpc: rmb fix Nick Piggin
2008-05-21 14:12 ` [patch 2/2] powerpc: optimise smp_wmb Nick Piggin
2008-05-21 15:26   ` Benjamin Herrenschmidt
2008-05-21 15:34     ` Nick Piggin
2008-05-21 15:43       ` Benjamin Herrenschmidt
2008-05-21 15:47         ` Nick Piggin
2008-05-21 16:02           ` Benjamin Herrenschmidt
2008-05-21 20:51             ` Segher Boessenkool
2008-05-21 16:01         ` Nick Piggin
2008-05-21 20:12           ` Segher Boessenkool
2008-05-21 20:44             ` Benjamin Herrenschmidt
2008-05-21 22:07               ` Segher Boessenkool
2008-05-22  0:30             ` Nick Piggin
2008-05-21 20:16   ` Segher Boessenkool
2008-05-21 15:27 ` Benjamin Herrenschmidt [this message]
2008-05-21 15:32   ` [patch 1/2] powerpc: rmb fix Nick Piggin
2008-05-21 15:43     ` Benjamin Herrenschmidt
2008-05-23  2:14     ` Paul Mackerras
2008-05-23  4:40       ` Nick Piggin
2008-05-23  4:53         ` Paul Mackerras
2008-05-23  5:48           ` Nick Piggin
2008-05-23  6:40             ` Paul Mackerras
2008-05-26  1:38               ` Nick Piggin
  -- strict thread matches above, loose matches on Subject: below --
2007-08-21  2:11 Nick Piggin
2007-08-21 19:07 ` Joel Schopp
2007-08-21 19:43   ` Segher Boessenkool
2007-08-21 21:42     ` Linas Vepstas
2007-08-22  1:16     ` Nick Piggin
2007-08-22  3:29       ` Segher Boessenkool
2007-08-22  3:55         ` Nick Piggin
2007-08-23 17:57           ` Segher Boessenkool
2007-08-24  2:47             ` Nick Piggin
2007-08-22  3:15     ` Nick Piggin
2007-08-22  3:33       ` Segher Boessenkool
2007-08-22  4:05         ` Nick Piggin
2007-08-23 17:49           ` Segher Boessenkool

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