linux-kernel - Re: [PATCH 0/7] preempt

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]

Message-ID: <20130913072459.GA15492@chicago.guarana.org>
Date:	Fri, 13 Sep 2013 17:25:00 +1000
From:	Kevin Easton <kevin@...rana.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...nel.org>,
	Andi Kleen <ak@...ux.intel.com>, Peter Anvin <hpa@...or.com>,
	Mike Galbraith <bitbucket@...ine.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 0/7] preempt_count rework -v2

On Thu, Sep 12, 2013 at 04:20:40AM +0200, Peter Zijlstra wrote:
> On Wed, Sep 11, 2013 at 04:02:14PM -0700, Linus Torvalds wrote:
> > On Wed, Sep 11, 2013 at 11:59 AM, Peter Zijlstra <peterz@...radead.org> wrote:
> > >
> > > OK, stripped it down further, I couldn't quite see how to collapse the
> > > unary and binary operator variants though :/
> > 
> > Ok, this looks pretty good. I assume it works too? ;)
> 
> Only compile tested that one.. the below is kvm boot tested until root
> mount -- I'll try on actual hardware when I've gotten some sleep.
> 
> I split the thing up into two macros GEN_UNARY_RMWcc and
> GEN_BINARY_RMWcc which ends up being more readable as well as smaller
> code overall.

If you wanted to collapse the unary and binary variants as you mentioned
upthread, you could do something like (for the CC_HAVE_ASM_GOTO case):

#define GEN_RMWcc(fullop, cc, ...) \
do { \
 asm volatile goto (fullop \
 "j" cc " %l[cc_label]" \
 : : __VA_ARGS__ \
 : "memory" : cc_label); \
 return 0; \
cc_label: \
 return 1; \
} while (0)

#define GEN_UNARY_RMWcc(op, var, arg0, cc) GEN_RMWcc(op " " arg0 ";", cc, "m" (var))
#define GEN_BINARY_RMWcc(op, var, val, arg0, cc) GEN_RMWcc(op " %1, " arg0 ";", cc, "m" (var), "er" (val))

    - Kevin
--
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/