WSL2-Linux-Kernel/arch/x86/xen/time.c

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 17:07:57 +03:00
// SPDX-License-Identifier: GPL-2.0
/*
* Xen time implementation.
*
* This is implemented in terms of a clocksource driver which uses
* the hypervisor clock as a nanosecond timebase, and a clockevent
* driver which uses the hypervisor's timer mechanism.
*
* Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
*/
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 11:04:11 +03:00
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/pvclock_gtod.h>
#include <linux/timekeeper_internal.h>
#include <asm/pvclock.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#include <xen/events.h>
#include <xen/features.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>
#include "xen-ops.h"
/* Minimum amount of time until next clock event fires */
#define TIMER_SLOP 100000
static u64 xen_sched_clock_offset __read_mostly;
/* Get the TSC speed from Xen */
static unsigned long xen_tsc_khz(void)
{
struct pvclock_vcpu_time_info *info =
&HYPERVISOR_shared_info->vcpu_info[0].time;
return pvclock_tsc_khz(info);
}
static u64 xen_clocksource_read(void)
{
struct pvclock_vcpu_time_info *src;
u64 ret;
preempt_disable_notrace();
src = &__this_cpu_read(xen_vcpu)->time;
ret = pvclock_clocksource_read(src);
preempt_enable_notrace();
return ret;
}
static u64 xen_clocksource_get_cycles(struct clocksource *cs)
{
return xen_clocksource_read();
}
static u64 xen_sched_clock(void)
{
return xen_clocksource_read() - xen_sched_clock_offset;
}
static void xen_read_wallclock(struct timespec64 *ts)
{
struct shared_info *s = HYPERVISOR_shared_info;
struct pvclock_wall_clock *wall_clock = &(s->wc);
struct pvclock_vcpu_time_info *vcpu_time;
vcpu_time = &get_cpu_var(xen_vcpu)->time;
pvclock_read_wallclock(wall_clock, vcpu_time, ts);
put_cpu_var(xen_vcpu);
}
static void xen_get_wallclock(struct timespec64 *now)
{
xen_read_wallclock(now);
}
static int xen_set_wallclock(const struct timespec64 *now)
{
return -ENODEV;
}
x86: xen: Sync the CMOS RTC as well as the Xen wallclock Adjustments to Xen's persistent clock via update_persistent_clock() don't actually persist, as the Xen wallclock is a software only clock and modifications to it do not modify the underlying CMOS RTC. The x86_platform.set_wallclock hook is there to keep the hardware RTC synchronized. On a guest this is pointless. On Dom0 we can use the native implementaion which actually updates the hardware RTC, but we still need to keep the software emulation of RTC for the guests up to date. The subscription to the pvclock_notifier allows us to emulate this easily. The notifier is called at every tick and when the clock was set. Right now we only use that notifier when the clock was set, but due to the fact that it is called periodically from the timekeeping update code, we can utilize it to emulate the NTP driven drift compensation of update_persistant_clock() for the Xen wall (software) clock. Add a 11 minutes periodic update to the pvclock_gtod notifier callback to achieve that. The static variable 'next' which maintains that 11 minutes update cycle is protected by the core code serialization so there is no need to add a Xen specific serialization mechanism. [ tglx: Massaged changelog and added a few comments ] Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-6-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-06-27 14:35:48 +04:00
static int xen_pvclock_gtod_notify(struct notifier_block *nb,
unsigned long was_set, void *priv)
{
x86: xen: Sync the CMOS RTC as well as the Xen wallclock Adjustments to Xen's persistent clock via update_persistent_clock() don't actually persist, as the Xen wallclock is a software only clock and modifications to it do not modify the underlying CMOS RTC. The x86_platform.set_wallclock hook is there to keep the hardware RTC synchronized. On a guest this is pointless. On Dom0 we can use the native implementaion which actually updates the hardware RTC, but we still need to keep the software emulation of RTC for the guests up to date. The subscription to the pvclock_notifier allows us to emulate this easily. The notifier is called at every tick and when the clock was set. Right now we only use that notifier when the clock was set, but due to the fact that it is called periodically from the timekeeping update code, we can utilize it to emulate the NTP driven drift compensation of update_persistant_clock() for the Xen wall (software) clock. Add a 11 minutes periodic update to the pvclock_gtod notifier callback to achieve that. The static variable 'next' which maintains that 11 minutes update cycle is protected by the core code serialization so there is no need to add a Xen specific serialization mechanism. [ tglx: Massaged changelog and added a few comments ] Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-6-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-06-27 14:35:48 +04:00
/* Protected by the calling core code serialization */
static struct timespec64 next_sync;
struct xen_platform_op op;
struct timespec64 now;
struct timekeeper *tk = priv;
static bool settime64_supported = true;
int ret;
now.tv_sec = tk->xtime_sec;
now.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
x86: xen: Sync the CMOS RTC as well as the Xen wallclock Adjustments to Xen's persistent clock via update_persistent_clock() don't actually persist, as the Xen wallclock is a software only clock and modifications to it do not modify the underlying CMOS RTC. The x86_platform.set_wallclock hook is there to keep the hardware RTC synchronized. On a guest this is pointless. On Dom0 we can use the native implementaion which actually updates the hardware RTC, but we still need to keep the software emulation of RTC for the guests up to date. The subscription to the pvclock_notifier allows us to emulate this easily. The notifier is called at every tick and when the clock was set. Right now we only use that notifier when the clock was set, but due to the fact that it is called periodically from the timekeeping update code, we can utilize it to emulate the NTP driven drift compensation of update_persistant_clock() for the Xen wall (software) clock. Add a 11 minutes periodic update to the pvclock_gtod notifier callback to achieve that. The static variable 'next' which maintains that 11 minutes update cycle is protected by the core code serialization so there is no need to add a Xen specific serialization mechanism. [ tglx: Massaged changelog and added a few comments ] Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-6-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-06-27 14:35:48 +04:00
/*
* We only take the expensive HV call when the clock was set
* or when the 11 minutes RTC synchronization time elapsed.
*/
if (!was_set && timespec64_compare(&now, &next_sync) < 0)
x86: xen: Sync the CMOS RTC as well as the Xen wallclock Adjustments to Xen's persistent clock via update_persistent_clock() don't actually persist, as the Xen wallclock is a software only clock and modifications to it do not modify the underlying CMOS RTC. The x86_platform.set_wallclock hook is there to keep the hardware RTC synchronized. On a guest this is pointless. On Dom0 we can use the native implementaion which actually updates the hardware RTC, but we still need to keep the software emulation of RTC for the guests up to date. The subscription to the pvclock_notifier allows us to emulate this easily. The notifier is called at every tick and when the clock was set. Right now we only use that notifier when the clock was set, but due to the fact that it is called periodically from the timekeeping update code, we can utilize it to emulate the NTP driven drift compensation of update_persistant_clock() for the Xen wall (software) clock. Add a 11 minutes periodic update to the pvclock_gtod notifier callback to achieve that. The static variable 'next' which maintains that 11 minutes update cycle is protected by the core code serialization so there is no need to add a Xen specific serialization mechanism. [ tglx: Massaged changelog and added a few comments ] Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-6-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-06-27 14:35:48 +04:00
return NOTIFY_OK;
again:
if (settime64_supported) {
op.cmd = XENPF_settime64;
op.u.settime64.mbz = 0;
op.u.settime64.secs = now.tv_sec;
op.u.settime64.nsecs = now.tv_nsec;
op.u.settime64.system_time = xen_clocksource_read();
} else {
op.cmd = XENPF_settime32;
op.u.settime32.secs = now.tv_sec;
op.u.settime32.nsecs = now.tv_nsec;
op.u.settime32.system_time = xen_clocksource_read();
}
ret = HYPERVISOR_platform_op(&op);
if (ret == -ENOSYS && settime64_supported) {
settime64_supported = false;
goto again;
}
if (ret < 0)
return NOTIFY_BAD;
x86: xen: Sync the CMOS RTC as well as the Xen wallclock Adjustments to Xen's persistent clock via update_persistent_clock() don't actually persist, as the Xen wallclock is a software only clock and modifications to it do not modify the underlying CMOS RTC. The x86_platform.set_wallclock hook is there to keep the hardware RTC synchronized. On a guest this is pointless. On Dom0 we can use the native implementaion which actually updates the hardware RTC, but we still need to keep the software emulation of RTC for the guests up to date. The subscription to the pvclock_notifier allows us to emulate this easily. The notifier is called at every tick and when the clock was set. Right now we only use that notifier when the clock was set, but due to the fact that it is called periodically from the timekeeping update code, we can utilize it to emulate the NTP driven drift compensation of update_persistant_clock() for the Xen wall (software) clock. Add a 11 minutes periodic update to the pvclock_gtod notifier callback to achieve that. The static variable 'next' which maintains that 11 minutes update cycle is protected by the core code serialization so there is no need to add a Xen specific serialization mechanism. [ tglx: Massaged changelog and added a few comments ] Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-6-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-06-27 14:35:48 +04:00
/*
* Move the next drift compensation time 11 minutes
* ahead. That's emulating the sync_cmos_clock() update for
* the hardware RTC.
*/
next_sync = now;
next_sync.tv_sec += 11 * 60;
return NOTIFY_OK;
}
static struct notifier_block xen_pvclock_gtod_notifier = {
.notifier_call = xen_pvclock_gtod_notify,
};
static struct clocksource xen_clocksource __read_mostly = {
.name = "xen",
.rating = 400,
.read = xen_clocksource_get_cycles,
.mask = ~0,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
Xen clockevent implementation
Xen has two clockevent implementations:
The old timer_op one works with all released versions of Xen prior
to version 3.0.4. This version of the hypervisor provides a
single-shot timer with nanosecond resolution. However, sharing the
same event channel is a 100Hz tick which is delivered while the
vcpu is running. We don't care about or use this tick, but it will
cause the core time code to think the timer fired too soon, and
will end up resetting it each time. It could be filtered, but
doing so has complications when the ktime clocksource is not yet
the xen clocksource (ie, at boot time).
The new vcpu_op-based timer interface allows the tick timer period
to be changed or turned off. The tick timer is not useful as a
periodic timer because events are only delivered to running vcpus.
The one-shot timer can report when a timeout is in the past, so
set_next_event is capable of returning -ETIME when appropriate.
This interface is used when available.
*/
/*
Get a hypervisor absolute time. In theory we could maintain an
offset between the kernel's time and the hypervisor's time, and
apply that to a kernel's absolute timeout. Unfortunately the
hypervisor and kernel times can drift even if the kernel is using
the Xen clocksource, because ntp can warp the kernel's clocksource.
*/
static s64 get_abs_timeout(unsigned long delta)
{
return xen_clocksource_read() + delta;
}
static int xen_timerop_shutdown(struct clock_event_device *evt)
{
/* cancel timeout */
HYPERVISOR_set_timer_op(0);
return 0;
}
static int xen_timerop_set_next_event(unsigned long delta,
struct clock_event_device *evt)
{
WARN_ON(!clockevent_state_oneshot(evt));
if (HYPERVISOR_set_timer_op(get_abs_timeout(delta)) < 0)
BUG();
/* We may have missed the deadline, but there's no real way of
knowing for sure. If the event was in the past, then we'll
get an immediate interrupt. */
return 0;
}
static struct clock_event_device xen_timerop_clockevent __ro_after_init = {
.name = "xen",
.features = CLOCK_EVT_FEAT_ONESHOT,
.max_delta_ns = 0xffffffff,
.max_delta_ticks = 0xffffffff,
.min_delta_ns = TIMER_SLOP,
.min_delta_ticks = TIMER_SLOP,
.mult = 1,
.shift = 0,
.rating = 500,
.set_state_shutdown = xen_timerop_shutdown,
.set_next_event = xen_timerop_set_next_event,
};
static int xen_vcpuop_shutdown(struct clock_event_device *evt)
{
int cpu = smp_processor_id();
if (HYPERVISOR_vcpu_op(VCPUOP_stop_singleshot_timer, xen_vcpu_nr(cpu),
NULL) ||
HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
NULL))
BUG();
return 0;
}
static int xen_vcpuop_set_oneshot(struct clock_event_device *evt)
{
int cpu = smp_processor_id();
if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
NULL))
BUG();
return 0;
}
static int xen_vcpuop_set_next_event(unsigned long delta,
struct clock_event_device *evt)
{
int cpu = smp_processor_id();
struct vcpu_set_singleshot_timer single;
int ret;
WARN_ON(!clockevent_state_oneshot(evt));
single.timeout_abs_ns = get_abs_timeout(delta);
/* Get an event anyway, even if the timeout is already expired */
single.flags = 0;
ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, xen_vcpu_nr(cpu),
&single);
BUG_ON(ret != 0);
return ret;
}
static struct clock_event_device xen_vcpuop_clockevent __ro_after_init = {
.name = "xen",
.features = CLOCK_EVT_FEAT_ONESHOT,
.max_delta_ns = 0xffffffff,
.max_delta_ticks = 0xffffffff,
.min_delta_ns = TIMER_SLOP,
.min_delta_ticks = TIMER_SLOP,
.mult = 1,
.shift = 0,
.rating = 500,
.set_state_shutdown = xen_vcpuop_shutdown,
.set_state_oneshot = xen_vcpuop_set_oneshot,
.set_next_event = xen_vcpuop_set_next_event,
};
static const struct clock_event_device *xen_clockevent =
&xen_timerop_clockevent;
struct xen_clock_event_device {
struct clock_event_device evt;
char name[16];
};
static DEFINE_PER_CPU(struct xen_clock_event_device, xen_clock_events) = { .evt.irq = -1 };
static irqreturn_t xen_timer_interrupt(int irq, void *dev_id)
{
x86: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Acked-by: H. Peter Anvin <hpa@linux.intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-17 21:30:40 +04:00
struct clock_event_device *evt = this_cpu_ptr(&xen_clock_events.evt);
irqreturn_t ret;
ret = IRQ_NONE;
if (evt->event_handler) {
evt->event_handler(evt);
ret = IRQ_HANDLED;
}
return ret;
}
void xen_teardown_timer(int cpu)
{
struct clock_event_device *evt;
evt = &per_cpu(xen_clock_events, cpu).evt;
if (evt->irq >= 0) {
unbind_from_irqhandler(evt->irq, NULL);
evt->irq = -1;
}
}
void xen_setup_timer(int cpu)
{
struct xen_clock_event_device *xevt = &per_cpu(xen_clock_events, cpu);
struct clock_event_device *evt = &xevt->evt;
int irq;
WARN(evt->irq >= 0, "IRQ%d for CPU%d is already allocated\n", evt->irq, cpu);
if (evt->irq >= 0)
xen_teardown_timer(cpu);
printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu);
snprintf(xevt->name, sizeof(xevt->name), "timer%d", cpu);
irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt,
IRQF_PERCPU|IRQF_NOBALANCING|IRQF_TIMER|
IRQF_FORCE_RESUME|IRQF_EARLY_RESUME,
xevt->name, NULL);
(void)xen_set_irq_priority(irq, XEN_IRQ_PRIORITY_MAX);
memcpy(evt, xen_clockevent, sizeof(*evt));
evt->cpumask = cpumask_of(cpu);
evt->irq = irq;
}
void xen_setup_cpu_clockevents(void)
{
x86: Replace __get_cpu_var uses __get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Acked-by: H. Peter Anvin <hpa@linux.intel.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2014-08-17 21:30:40 +04:00
clockevents_register_device(this_cpu_ptr(&xen_clock_events.evt));
}
void xen_timer_resume(void)
{
int cpu;
if (xen_clockevent != &xen_vcpuop_clockevent)
return;
for_each_online_cpu(cpu) {
if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer,
xen_vcpu_nr(cpu), NULL))
BUG();
}
}
static const struct pv_time_ops xen_time_ops __initconst = {
.sched_clock = xen_sched_clock,
.steal_clock = xen_steal_clock,
};
static struct pvclock_vsyscall_time_info *xen_clock __read_mostly;
static u64 xen_clock_value_saved;
void xen_save_time_memory_area(void)
{
struct vcpu_register_time_memory_area t;
int ret;
xen_clock_value_saved = xen_clocksource_read() - xen_sched_clock_offset;
if (!xen_clock)
return;
t.addr.v = NULL;
ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
if (ret != 0)
pr_notice("Cannot save secondary vcpu_time_info (err %d)",
ret);
else
clear_page(xen_clock);
}
void xen_restore_time_memory_area(void)
{
struct vcpu_register_time_memory_area t;
int ret;
if (!xen_clock)
goto out;
t.addr.v = &xen_clock->pvti;
ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
/*
* We don't disable VCLOCK_PVCLOCK entirely if it fails to register the
* secondary time info with Xen or if we migrated to a host without the
* necessary flags. On both of these cases what happens is either
* process seeing a zeroed out pvti or seeing no PVCLOCK_TSC_STABLE_BIT
* bit set. Userspace checks the latter and if 0, it discards the data
* in pvti and fallbacks to a system call for a reliable timestamp.
*/
if (ret != 0)
pr_notice("Cannot restore secondary vcpu_time_info (err %d)",
ret);
out:
/* Need pvclock_resume() before using xen_clocksource_read(). */
pvclock_resume();
xen_sched_clock_offset = xen_clocksource_read() - xen_clock_value_saved;
}
static void xen_setup_vsyscall_time_info(void)
{
struct vcpu_register_time_memory_area t;
struct pvclock_vsyscall_time_info *ti;
int ret;
ti = (struct pvclock_vsyscall_time_info *)get_zeroed_page(GFP_KERNEL);
if (!ti)
return;
t.addr.v = &ti->pvti;
ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
if (ret) {
pr_notice("xen: VCLOCK_PVCLOCK not supported (err %d)\n", ret);
free_page((unsigned long)ti);
return;
}
/*
* If primary time info had this bit set, secondary should too since
* it's the same data on both just different memory regions. But we
* still check it in case hypervisor is buggy.
*/
if (!(ti->pvti.flags & PVCLOCK_TSC_STABLE_BIT)) {
t.addr.v = NULL;
ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area,
0, &t);
if (!ret)
free_page((unsigned long)ti);
pr_notice("xen: VCLOCK_PVCLOCK not supported (tsc unstable)\n");
return;
}
xen_clock = ti;
pvclock_set_pvti_cpu0_va(xen_clock);
xen_clocksource.archdata.vclock_mode = VCLOCK_PVCLOCK;
}
static void __init xen_time_init(void)
{
struct pvclock_vcpu_time_info *pvti;
int cpu = smp_processor_id();
struct timespec64 tp;
/* As Dom0 is never moved, no penalty on using TSC there */
if (xen_initial_domain())
xen_clocksource.rating = 275;
clocksource_register_hz(&xen_clocksource, NSEC_PER_SEC);
if (HYPERVISOR_vcpu_op(VCPUOP_stop_periodic_timer, xen_vcpu_nr(cpu),
NULL) == 0) {
/* Successfully turned off 100Hz tick, so we have the
vcpuop-based timer interface */
printk(KERN_DEBUG "Xen: using vcpuop timer interface\n");
xen_clockevent = &xen_vcpuop_clockevent;
}
/* Set initial system time with full resolution */
xen_read_wallclock(&tp);
do_settimeofday64(&tp);
setup_force_cpu_cap(X86_FEATURE_TSC);
/*
* We check ahead on the primary time info if this
* bit is supported hence speeding up Xen clocksource.
*/
pvti = &__this_cpu_read(xen_vcpu)->time;
if (pvti->flags & PVCLOCK_TSC_STABLE_BIT) {
pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
xen_setup_vsyscall_time_info();
}
xen_setup_runstate_info(cpu);
xen_setup_timer(cpu);
xen_setup_cpu_clockevents();
xen_time_setup_guest();
if (xen_initial_domain())
pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
}
void __init xen_init_time_ops(void)
{
xen_sched_clock_offset = xen_clocksource_read();
pv_ops.time = xen_time_ops;
x86_init.timers.timer_init = xen_time_init;
x86_init.timers.setup_percpu_clockev = x86_init_noop;
x86_cpuinit.setup_percpu_clockev = x86_init_noop;
x86_platform.calibrate_tsc = xen_tsc_khz;
x86_platform.get_wallclock = xen_get_wallclock;
x86: xen: Sync the CMOS RTC as well as the Xen wallclock Adjustments to Xen's persistent clock via update_persistent_clock() don't actually persist, as the Xen wallclock is a software only clock and modifications to it do not modify the underlying CMOS RTC. The x86_platform.set_wallclock hook is there to keep the hardware RTC synchronized. On a guest this is pointless. On Dom0 we can use the native implementaion which actually updates the hardware RTC, but we still need to keep the software emulation of RTC for the guests up to date. The subscription to the pvclock_notifier allows us to emulate this easily. The notifier is called at every tick and when the clock was set. Right now we only use that notifier when the clock was set, but due to the fact that it is called periodically from the timekeeping update code, we can utilize it to emulate the NTP driven drift compensation of update_persistant_clock() for the Xen wall (software) clock. Add a 11 minutes periodic update to the pvclock_gtod notifier callback to achieve that. The static variable 'next' which maintains that 11 minutes update cycle is protected by the core code serialization so there is no need to add a Xen specific serialization mechanism. [ tglx: Massaged changelog and added a few comments ] Signed-off-by: David Vrabel <david.vrabel@citrix.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: John Stultz <john.stultz@linaro.org> Cc: <xen-devel@lists.xen.org> Link: http://lkml.kernel.org/r/1372329348-20841-6-git-send-email-david.vrabel@citrix.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-06-27 14:35:48 +04:00
/* Dom0 uses the native method to set the hardware RTC. */
if (!xen_initial_domain())
x86_platform.set_wallclock = xen_set_wallclock;
}
#ifdef CONFIG_XEN_PVHVM
static void xen_hvm_setup_cpu_clockevents(void)
{
int cpu = smp_processor_id();
xen_setup_runstate_info(cpu);
/*
* xen_setup_timer(cpu) - snprintf is bad in atomic context. Hence
* doing it xen_hvm_cpu_notify (which gets called by smp_init during
* early bootup and also during CPU hotplug events).
*/
xen_setup_cpu_clockevents();
}
void __init xen_hvm_init_time_ops(void)
{
xen: Revert commits da72ff5bfcb0 and 72a9b186292d Recent discussion (http://marc.info/?l=xen-devel&m=149192184523741) established that commit 72a9b186292d ("xen: Remove event channel notification through Xen PCI platform device") (and thus commit da72ff5bfcb0 ("partially revert "xen: Remove event channel notification through Xen PCI platform device"")) are unnecessary and, in fact, prevent HVM guests from booting on Xen releases prior to 4.0 Therefore we revert both of those commits. The summary of that discussion is below: Here is the brief summary of the current situation: Before the offending commit (72a9b186292): 1) INTx does not work because of the reset_watches path. 2) The reset_watches path is only taken if you have Xen > 4.0 3) The Linux Kernel by default will use vector inject if the hypervisor support. So even INTx does not work no body running the kernel with Xen > 4.0 would notice. Unless he explicitly disabled this feature either in the kernel or in Xen (and this can only be disabled by modifying the code, not user-supported way to do it). After the offending commit (+ partial revert): 1) INTx is no longer support for HVM (only for PV guests). 2) Any HVM guest The kernel will not boot on Xen < 4.0 which does not have vector injection support. Since the only other mode supported is INTx which. So based on this summary, I think before commit (72a9b186292) we were in much better position from a user point of view. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
2017-04-24 22:04:53 +03:00
/*
* vector callback is needed otherwise we cannot receive interrupts
* on cpu > 0 and at this point we don't know how many cpus are
* available.
*/
if (!xen_have_vector_callback)
return;
if (!xen_feature(XENFEAT_hvm_safe_pvclock)) {
pr_info("Xen doesn't support pvclock on HVM, disable pv timer");
return;
}
xen_sched_clock_offset = xen_clocksource_read();
pv_ops.time = xen_time_ops;
x86_init.timers.setup_percpu_clockev = xen_time_init;
x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
x86_platform.calibrate_tsc = xen_tsc_khz;
x86_platform.get_wallclock = xen_get_wallclock;
x86_platform.set_wallclock = xen_set_wallclock;
}
#endif
/* Kernel parameter to specify Xen timer slop */
static int __init parse_xen_timer_slop(char *ptr)
{
unsigned long slop = memparse(ptr, NULL);
xen_timerop_clockevent.min_delta_ns = slop;
xen_timerop_clockevent.min_delta_ticks = slop;
xen_vcpuop_clockevent.min_delta_ns = slop;
xen_vcpuop_clockevent.min_delta_ticks = slop;
return 0;
}
early_param("xen_timer_slop", parse_xen_timer_slop);