From: Arne Georg Gleditsch <arne.gleditsch@dolphinics.no>
To: linux-kernel@vger.kernel.org
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Subject: arch/x86/kernel/vsyscall_64.c: overeager NOP of syscalls
Date: Wed, 20 Feb 2008 14:57:34 +0100 [thread overview]
Message-ID: <kjm4pc3d92p.fsf@pelargir.dolphinics.no> (raw)
Hi,
I'm looking at 2.6.25-rc2. vsyscall_sysctl_change contains code to NOP
out the actual system call instructions of the vsyscall page when
vsyscall64 is enabled. This seems to interact badly with the fallback
code in do_vgettimeofday which tries to call gettimeofday if the
configured clock source does not support vread. (In effect,
gettimeofday() becomes a nop and time() always returns 0. Not very
useful.)
Is there a good reason to keep this? Aren't the instructions in
question avoided (or invoked) according to the vsyscall64 flag by the
surrounding logic anyway?
--
Arne.
next reply other threads:[~2008-02-20 14:26 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-20 13:57 Arne Georg Gleditsch [this message]
2008-02-20 18:08 ` arch/x86/kernel/vsyscall_64.c: overeager NOP of syscalls Thomas Gleixner
2008-02-21 15:58 ` Andi Kleen
2008-02-21 19:45 ` Thomas Gleixner
2008-02-21 20:02 ` john stultz
2008-02-21 20:47 ` Thomas Gleixner
2008-02-21 20:59 ` Thomas Gleixner
2008-02-22 12:55 ` Andi Kleen
2008-02-22 12:49 ` Andi Kleen
2008-02-22 10:38 ` Arne Georg Gleditsch
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