From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: David Howells <dhowells@redhat.com>
Cc: gcc-help@gcc.gnu.org, linuxppc-dev@ozlabs.org,
kernel mailz <kernelmailz@googlemail.com>
Subject: Re: Inline Assembly queries
Date: Tue, 30 Jun 2009 20:43:03 +1000 [thread overview]
Message-ID: <1246358583.31413.11.camel@pasglop> (raw)
In-Reply-To: <30098.1246291036@redhat.com>
On Mon, 2009-06-29 at 16:57 +0100, David Howells wrote:
> kernel mailz <kernelmailz@googlemail.com> wrote:
>
> > asm("sync");
>
> Isn't gcc free to discard this as it has no dependencies, no indicated side
> effects, and isn't required to be kept? I think this should probably be:
>
> asm volatile("sync");
It should also have a "memory" clobber or it's pointless since gcc would
otherwise be free to move load and stores accross that barrier.
Cheers,
Ben.
prev parent reply other threads:[~2009-06-30 10:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-27 19:46 Inline Assembly queries kernel mailz
[not found] ` <abe8a1fd0906271249k479e5a87gfe1ee9c02798a234@mail.gmail.com>
[not found] ` <m3ab3t4623.fsf@google.com>
2009-06-28 4:57 ` kernel mailz
2009-06-29 15:49 ` kernel mailz
2009-06-29 19:27 ` Scott Wood
2009-06-30 5:27 ` kernel mailz
2009-06-30 10:41 ` Benjamin Herrenschmidt
2009-06-29 21:29 ` Ian Lance Taylor
2009-06-30 5:53 ` kernel mailz
2009-06-30 9:30 ` Andrew Haley
2009-06-30 9:52 ` Paul Mackerras
2009-06-29 15:57 ` David Howells
2009-06-29 21:27 ` Ian Lance Taylor
2009-06-30 10:43 ` Benjamin Herrenschmidt [this message]
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