linux-kernel - Re: [discuss] [PATCH 4/4 TRY#3] optimize and simplify get_cycles

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 12 Mar 2007 14:45:00 +0100
From:	"Joerg Roedel" <joerg.roedel@....com>
To:	"Michael Matz" <matz@...e.de>
cc:	"Avi Kivity" <avi@...o.co.il>, discuss@...-64.org,
	"Andi Kleen" <ak@...e.de>, linux-kernel@...r.kernel.org
Subject: Re: [discuss] [PATCH 4/4 TRY#3] optimize and simplify
 get_cycles_sync()

On Mon, Mar 12, 2007 at 02:29:43PM +0100, Michael Matz wrote:
> Hi Joerg,
> 
> On Mon, 12 Mar 2007, Joerg Roedel wrote:
> 
> > > >+#define RDTSCP ".byte 0x0f, 0x01, 0xf9"
> > > >+	alternative_io_two("cpuid\nrdtsc",
> > > >+			   "rdtsc", X86_FEATURE_SYNC_RDTSC,
> > > >+			   ".byte 0x0f, 0x01, 0xf9", X86_FEATURE_RDTSCP,
> > > >  
> > > 
> > > why not use the RDTSCP macro here?
> > 
> > Does this macro exist?
> 
> Look carefully at your patch again, or at least the four quoted lines 
> above.  You've added it yourself, in exactly the form you'd need in the 
> alternative_io_two() call :-)

Hmmkay, thanks for opening my eyes :-)
I considered defining this macro while writing this patch, but decided
against this because the X86_FEATURE_RDTSCP on the same line should
documenting the opcode sufficiently. I just forgot to remove that
#define :)

Thanks again,
Joerg

-- 
Joerg Roedel
Operating System Research Center
AMD Saxony LLC & Co. KG


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/