From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 7/7] xen/arm: set the system time in Xen via the XENPF_settime64 hypercall
Date: Tue, 10 Nov 2015 13:39:44 +0100 [thread overview]
Message-ID: <4039287.QS1nrAMb0E@wuerfel> (raw)
In-Reply-To: <1447156675-7418-7-git-send-email-stefano.stabellini@eu.citrix.com>
On Tuesday 10 November 2015 11:57:55 Stefano Stabellini wrote:
> + op.u.settime64.nsecs = now.tv_nsec;
> + op.u.settime64.system_time = arch_timer_read_counter() * (u64)NSEC_PER_SEC;
> + do_div(op.u.settime64.system_time, arch_timer_get_rate());
NSEC_PER_SEC is a large number, doesn't that multiplication overflow the
64-bit system_time variable?
> + printk("GTOD: Setting to %llu.%u at %llu\n",
%llu.%09u
so you get the leading zeroes.
> + op.u.settime64.secs,
> + op.u.settime64.nsecs,
> + op.u.settime64.system_time);
> + (void)HYPERVISOR_platform_op(&op);
Arnd
next prev parent reply other threads:[~2015-11-10 12:39 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-10 11:56 [PATCH v2 0/7] Xen wallclock on arm and arm64 Stefano Stabellini
2015-11-10 11:57 ` [PATCH v2 1/7] timekeeping: introduce __current_kernel_time64 Stefano Stabellini
2015-11-10 12:22 ` Peter Zijlstra
2015-11-10 14:34 ` Stefano Stabellini
2015-11-10 12:29 ` Arnd Bergmann
2015-11-10 15:10 ` Stefano Stabellini
2015-11-10 15:26 ` John Stultz
2015-11-10 15:31 ` Thomas Gleixner
2015-11-10 15:41 ` John Stultz
2015-11-10 15:55 ` Thomas Gleixner
2015-11-11 11:51 ` Stefano Stabellini
2015-11-11 13:31 ` Arnd Bergmann
2015-11-10 11:57 ` [PATCH v2 2/7] xen: rename dom0_op to platform_op Stefano Stabellini
2015-11-10 11:57 ` [PATCH v2 3/7] xen/arm: introduce HYPERVISOR_platform_op on arm and arm64 Stefano Stabellini
2015-11-10 11:57 ` [PATCH v2 4/7] xen: introduce XENPF_settime64 Stefano Stabellini
2015-11-10 12:32 ` Arnd Bergmann
2015-11-10 14:43 ` Stefano Stabellini
2015-11-10 14:47 ` Arnd Bergmann
2015-11-10 11:57 ` [PATCH v2 5/7] arm: extend pvclock_wall_clock with sec_hi Stefano Stabellini
2015-11-10 11:57 ` [PATCH v2 6/7] xen/arm: introduce xen_read_wallclock Stefano Stabellini
2015-11-10 12:35 ` Arnd Bergmann
2015-11-10 11:57 ` [PATCH v2 7/7] xen/arm: set the system time in Xen via the XENPF_settime64 hypercall Stefano Stabellini
2015-11-10 12:39 ` Arnd Bergmann [this message]
2015-11-10 15:58 ` Stefano Stabellini
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