linux-kernel - Re: [PATCH] x86: fix ticket spin lock asm constraints

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:	Sat, 30 Aug 2008 07:28:01 +0200
From:	Nick Piggin <npiggin@...e.de>
To:	Jan Beulich <jbeulich@...ell.com>
Cc:	mingo@...e.hu, tglx@...utronix.de, hpa@...or.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: fix ticket spin lock asm constraints

Hi,

All these ticket lock patches look pretty good to me. Thanks for going over
it so thoroughly.

On Fri, Aug 29, 2008 at 12:54:59PM +0100, Jan Beulich wrote:
> In addition to these changes I doubt the 'volatile' on all the ticket
> lock asm()-s are really necessary.
> 
> Signed-off-by: Jan Beulich <jbeulich@...ell.com>
> Cc: Nick Piggin <npiggin@...e.de>
> 
> ---
>  include/asm-x86/spinlock.h |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> --- linux-2.6.27-rc5/include/asm-x86/spinlock.h	2008-08-21 14:37:34.000000000 +0200
> +++ 2.6.27-rc5-x86-spinlock-constraints/include/asm-x86/spinlock.h	2008-08-19 12:43:22.000000000 +0200
> @@ -101,7 +101,7 @@ static __always_inline int __ticket_spin
>  		     "1:"
>  		     "sete %b1\n\t"
>  		     "movzbl %b1,%0\n\t"
> -		     : "=&a" (tmp), "=Q" (new), "+m" (lock->slock)
> +		     : "=&a" (tmp), "=&Q" (new), "+m" (lock->slock)
>  		     :
>  		     : "memory", "cc");
>  
> @@ -146,7 +146,7 @@ static __always_inline void __ticket_spi
>  		     /* don't need lfence here, because loads are in-order */
>  		     "jmp 1b\n"
>  		     "2:"
> -		     : "+Q" (inc), "+m" (lock->slock), "=r" (tmp)
> +		     : "+r" (inc), "+m" (lock->slock), "=&r" (tmp)
>  		     :
>  		     : "memory", "cc");
>  }
> @@ -166,7 +166,7 @@ static __always_inline int __ticket_spin
>  		     "1:"
>  		     "sete %b1\n\t"
>  		     "movzbl %b1,%0\n\t"
> -		     : "=&a" (tmp), "=r" (new), "+m" (lock->slock)
> +		     : "=&a" (tmp), "=&q" (new), "+m" (lock->slock)
>  		     :
>  		     : "memory", "cc");
>  
> 
> 
--
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/