linux-kernel - [PATCH] [26/34] i386: remove xtime_lock'ing around cpufreq notifier

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, 30 Apr 2007 17:49:59 +0200 (CEST)
From:	Andi Kleen <ak@...e.de>
To:	dwalker@...sta.com, ak@...e.de, mingo@...e.hu, tglx@...utronix.de,
	johnstul@...ibm.com, patches@...-64.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] [26/34] i386: remove xtime_lock'ing around cpufreq notifier


From: Daniel Walker <dwalker@...sta.com>

The locking of the xtime_lock around the cpu notifier is unessesary now. 
At one time the tsc was used after a frequency change for timekeeping, but
the re-write of timekeeping no longer uses the TSC unless the frequency is
constant.

The variables that are changed in this section of code had also once been
used for timekeeping, but not any longer ..

Signed-off-by: Daniel Walker <dwalker@...sta.com>
Signed-off-by: Andi Kleen <ak@...e.de>
Cc: Andi Kleen <ak@...e.de>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: john stultz <johnstul@...ibm.com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
---

 arch/i386/kernel/tsc.c |    8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

Index: linux/arch/i386/kernel/tsc.c
===================================================================
--- linux.orig/arch/i386/kernel/tsc.c
+++ linux/arch/i386/kernel/tsc.c
@@ -144,13 +144,10 @@ time_cpufreq_notifier(struct notifier_bl
 {
 	struct cpufreq_freqs *freq = data;
 
-	if (val != CPUFREQ_RESUMECHANGE && val != CPUFREQ_SUSPENDCHANGE)
-		write_seqlock_irq(&xtime_lock);
-
 	if (!ref_freq) {
 		if (!freq->old){
 			ref_freq = freq->new;
-			goto end;
+			return 0;
 		}
 		ref_freq = freq->old;
 		loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
@@ -176,9 +173,6 @@ time_cpufreq_notifier(struct notifier_bl
 			}
 		}
 	}
-end:
-	if (val != CPUFREQ_RESUMECHANGE && val != CPUFREQ_SUSPENDCHANGE)
-		write_sequnlock_irq(&xtime_lock);
 
 	return 0;
 }
-
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/