linux-kernel - Re: [PATCH 3/6] x86: Add support for the clwb instruction

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:	Tue, 11 Nov 2014 20:46:21 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Ross Zwisler <ross.zwisler@...ux.intel.com>
Cc:	linux-kernel@...r.kernel.org,
	H Peter Anvin <h.peter.anvin@...el.com>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	David Airlie <airlied@...ux.ie>,
	dri-devel@...ts.freedesktop.org, x86@...nel.org
Subject: Re: [PATCH 3/6] x86: Add support for the clwb instruction

On Tue, Nov 11, 2014 at 12:40:00PM -0700, Ross Zwisler wrote:
> Yep, it's weird, I know.  :)

But sure, saving opcode space, makes sense to me.

Btw, I'd still be interested about this:

> +static inline void clwb(volatile void *__p)
> +{
> +     alternative_io_2(".byte " __stringify(NOP_DS_PREFIX) "; clflush %P0",

Any particular reason for using 0x3e as a prefix to have the insns be
the same size or is it simply because CLFLUSH can stomach it?

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--
--
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/