From: Richard Cochran <richardcochran@gmail.com>
To: John Stultz <john.stultz@linaro.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
linux-kernel <linux-kernel@vger.kernel.org>,
Tony Luck <tony.luck@intel.com>,
Paul Mackerras <paulus@samba.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Paul Turner <pjt@google.com>,
Steven Rostedt <rostedt@goodmis.org>,
Prarit Bhargava <prarit@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH 0/6][RFC] Rework vsyscall to avoid truncation/rounding issue in timekeeping core
Date: Wed, 19 Sep 2012 19:03:47 +0200 [thread overview]
Message-ID: <20120919170347.GA2232@netboy.at.omicron.at> (raw)
In-Reply-To: <5059F367.5020104@linaro.org>
On Wed, Sep 19, 2012 at 09:31:35AM -0700, John Stultz wrote:
> On powerpc, I mean magic addresses where userland can find
> structures that it can use to calculate time.
...
> With powerpc, there is no arch specific kernel code involved, its
> just a data structure the kernel exports that is accessible to
> userland. The execution logic lives in userland libraries, or
> sometimes application code itself.
I took a brief look at arch/powerpc/kernel/vdso32/gettimeofday.S and
arch/powerpc/kernel/vdso64/gettimeofday.S, and I see what looks a lot
like functions
$ find arch/powerpc/kernel/vdso* -name gettimeofday.S|xargs grep FUNCTION_BEGIN
arch/powerpc/kernel/vdso32/gettimeofday.S:V_FUNCTION_BEGIN(__kernel_gettimeofday)
arch/powerpc/kernel/vdso32/gettimeofday.S:V_FUNCTION_BEGIN(__kernel_clock_gettime)
arch/powerpc/kernel/vdso32/gettimeofday.S:V_FUNCTION_BEGIN(__kernel_clock_getres)
arch/powerpc/kernel/vdso64/gettimeofday.S:V_FUNCTION_BEGIN(__kernel_gettimeofday)
arch/powerpc/kernel/vdso64/gettimeofday.S:V_FUNCTION_BEGIN(__kernel_clock_gettime)
arch/powerpc/kernel/vdso64/gettimeofday.S:V_FUNCTION_BEGIN(__kernel_clock_getres)
arch/powerpc/kernel/vdso64/gettimeofday.S:V_FUNCTION_BEGIN(__do_get_tspec)
and I wonder whether these could be done in C instead.
Thanks,
Richard
next prev parent reply other threads:[~2012-09-19 17:04 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-17 22:04 John Stultz
2012-09-17 22:04 ` [PATCH 1/6][RFC] time: Move timekeeper structure to timekeeper_internal.h for vsyscall changes John Stultz
2012-09-17 22:04 ` [PATCH 2/6][RFC] time: Move update_vsyscall definitions to timekeeper_internal.h John Stultz
2012-09-27 3:14 ` Paul Mackerras
2012-09-17 22:04 ` [PATCH 3/6][RFC] time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD John Stultz
2012-09-27 3:14 ` Paul Mackerras
2012-09-17 22:04 ` [PATCH 4/6][RFC] time: Introduce new GENERIC_TIME_VSYSCALL John Stultz
2012-09-17 22:05 ` [PATCH 5/6][RFC] time: Only do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD systems John Stultz
2012-09-17 22:05 ` [PATCH 6/6][RFC] time: Convert x86_64 to using new update_vsyscall John Stultz
2012-09-17 23:49 ` [PATCH 0/6][RFC] Rework vsyscall to avoid truncation/rounding issue in timekeeping core Andy Lutomirski
2012-09-18 0:20 ` John Stultz
2012-09-18 0:43 ` Andy Lutomirski
2012-09-18 18:02 ` Richard Cochran
2012-09-18 18:17 ` Andy Lutomirski
2012-09-18 18:29 ` John Stultz
2012-09-19 4:50 ` Richard Cochran
2012-09-19 5:30 ` Andy Lutomirski
2012-09-19 16:31 ` John Stultz
2012-09-19 17:03 ` Richard Cochran [this message]
2012-09-19 17:54 ` John Stultz
2012-09-19 18:26 ` Andy Lutomirski
2012-09-19 20:50 ` Luck, Tony
2012-09-19 21:11 ` John Stultz
2012-09-20 7:36 ` Richard Cochran
2012-09-19 21:15 ` Andy Lutomirski
2012-09-20 14:31 ` Steven Rostedt
2012-09-20 17:32 ` Andy Lutomirski
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