From: David Laight <David.Laight@ACULAB.COM>
To: 'Borislav Petkov' <bp@alien8.de>
Cc: Michael Matz <matz@suse.de>, 'Dave Jiang' <dave.jiang@intel.com>,
"vkoul@kernel.org" <vkoul@kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"mingo@redhat.com" <mingo@redhat.com>,
"dan.j.williams@intel.com" <dan.j.williams@intel.com>,
"tony.luck@intel.com" <tony.luck@intel.com>,
"jing.lin@intel.com" <jing.lin@intel.com>,
"ashok.raj@intel.com" <ashok.raj@intel.com>,
"sanjay.k.kumar@intel.com" <sanjay.k.kumar@intel.com>,
"fenghua.yu@intel.com" <fenghua.yu@intel.com>,
"kevin.tian@intel.com" <kevin.tian@intel.com>,
"dmaengine@vger.kernel.org" <dmaengine@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v5 1/5] x86/asm: Carve out a generic movdir64b() helper for general usage
Date: Thu, 24 Sep 2020 11:25:27 +0000 [thread overview]
Message-ID: <ba7e555d0dea42eb97d8b08df69b3191@AcuMS.aculab.com> (raw)
In-Reply-To: <20200924110207.GE5030@zn.tnic>
> > No, that just says the asm uses the value of the pointer.
> > Not what it points to.
>
> Err, no, it is *exactly* what it points to that is important here and
> you're telling the compiler that the instruction will read that much
> memory through the pointer.
You need to use an "m" constraint for that.
A 'register' constraint just requires the value of the address
to be valid.
Look at the asm output from the example code I posted.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2020-09-24 11:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <160090233730.44288.4446779116422752486.stgit@djiang5-desk3.ch.intel.com>
2020-09-23 23:10 ` [PATCH v5 3/5] dmaengine: idxd: Add shared workqueue support Dave Jiang
2020-09-23 23:11 ` [PATCH v5 4/5] dmaengine: idxd: Clean up descriptors with fault error Dave Jiang
2020-09-23 23:11 ` [PATCH v5 5/5] dmaengine: idxd: Add ABI documentation for shared wq Dave Jiang
[not found] ` <160090264332.44288.7575027054245105525.stgit@djiang5-desk3.ch.intel.com>
2020-09-24 8:24 ` [PATCH v5 1/5] x86/asm: Carve out a generic movdir64b() helper for general usage David Laight
2020-09-24 10:15 ` Borislav Petkov
2020-09-24 10:42 ` David Laight
2020-09-24 11:02 ` Borislav Petkov
2020-09-24 11:25 ` David Laight [this message]
2020-09-24 14:07 ` Michael Matz
2020-09-24 13:07 ` Borislav Petkov
2020-09-24 13:27 ` David Laight
2020-09-24 15:07 ` Dave Jiang
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