From: Andi Kleen <ak@suse.de>
To: cebbert@redhat.com, torvalds@osdl.org, patches@x86-64.org,
linux-kernel@vger.kernel.org
Subject: [PATCH for 2.6.23] [1/3] x86_64: Add missing mask operation to vdso
Date: Tue, 11 Sep 2007 14:02:09 +0200 (CEST) [thread overview]
Message-ID: <20070911120210.0CFFC14EEC@wotan.suse.de> (raw)
In-Reply-To: <20070911202.911586000@suse.de>
vdso vgetns() didn't mask the time source offset calculation, which could
lead to time problems with 32bit HPET. Add the masking.
Thanks to Chuck Ebbert for tracking down.
Cc: cebbert@redhat.com
Signed-off-by: Andi Kleen <ak@suse.de>
Index: linux/arch/x86_64/vdso/vclock_gettime.c
===================================================================
--- linux.orig/arch/x86_64/vdso/vclock_gettime.c
+++ linux/arch/x86_64/vdso/vclock_gettime.c
@@ -34,10 +34,11 @@ static long vdso_fallback_gettime(long c
static inline long vgetns(void)
{
+ long v;
cycles_t (*vread)(void);
vread = gtod->clock.vread;
- return ((vread() - gtod->clock.cycle_last) * gtod->clock.mult) >>
- gtod->clock.shift;
+ v = (vread() - gtod->clock.cycle_last) & gtod->clock.mask;
+ return (v * gtod->clock.mult) >> gtod->clock.shift;
}
static noinline int do_realtime(struct timespec *ts)
next prev parent reply other threads:[~2007-09-11 12:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-11 12:02 [PATCH for 2.6.23] [0/3] More last minute bug fixes for x86 Andi Kleen
2007-09-11 12:02 ` Andi Kleen [this message]
2007-09-11 12:02 ` [PATCH for 2.6.23] [2/3] x86_64: Prevent doing anything from cache_remove_dev() when info setup failed Andi Kleen
2007-09-13 9:32 ` Andi Kleen
2007-09-11 12:02 ` [PATCH for 2.6.23] [3/3] i386: Fix leak of ../kernel from top level Andi Kleen
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