linux-kernel - x86: udelay: Use this_cpu_read to avoid address calculation

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: <alpine.DEB.2.00.1012161214040.21588@router.home>
Date:	Thu, 16 Dec 2010 12:14:43 -0600 (CST)
From:	Christoph Lameter <cl@...ux.com>
To:	Tejun Heo <htejun@...il.com>
cc:	"H. Peter Anvin" <hpa@...or.com>,
	Eric Dumazet <eric.dumazet@...il.com>,
	akpm@...ux-foundation.org, Pekka Enberg <penberg@...helsinki.fi>,
	linux-kernel@...r.kernel.org,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Subject: x86: udelay: Use this_cpu_read to avoid address calculation

The code will use a segment prefix instead of doing the lookup and calculation.

Signed-off-by: Christoph Lameter <cl@...ux.com>

---
 arch/x86/lib/delay.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6/arch/x86/lib/delay.c
===================================================================
--- linux-2.6.orig/arch/x86/lib/delay.c	2010-12-16 11:45:12.000000000 -0600
+++ linux-2.6/arch/x86/lib/delay.c	2010-12-16 11:45:37.000000000 -0600
@@ -121,7 +121,7 @@ inline void __const_udelay(unsigned long
 	asm("mull %%edx"
 		:"=d" (xloops), "=&a" (d0)
 		:"1" (xloops), "0"
-		(cpu_data(raw_smp_processor_id()).loops_per_jiffy * (HZ/4)));
+		(this_cpu_read(cpu_info.loops_per_jiffy) * (HZ/4)));

 	__delay(++xloops);
 }

--
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/