From 2e16f46da8c53d2a4e22bbc9b31c704a09c03329 Mon Sep 17 00:00:00 2001
From: Jacob Pan <jacob.jun.pan@linux.intel.com>
Date: Tue, 14 May 2019 21:41:34 +0800
Subject: [PATCH] x86/apic: Unify duplicated local apic timer clockevent
initialization
mainline inclusion
from mainline-6eb4f08293e9 undefined
commit 6eb4f08293e9
category: bugfix
bugzilla: 14416
CVE: NA
-------------------------------------------------
Local APIC timer clockevent parameters can be calculated based on platform
specific methods. However the code is mostly duplicated with the interrupt
based calibration. The commit which increased the max_delta parameter
updated only one place and made the implementations diverge.
Unify it to prevent further damage.
[ tglx: Rename function to lapic_init_clockevent() and adjust changelog a bit ]
Fixes: 4aed89d6b515 ("x86, lapic-timer: Increase the max_delta to 31 bits")
Reported-by: Daniel Drake <drake@endlessm.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/1556213272-63568-1-git-send-email-jacob.jun.pan@linux.intel.com
Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
Reviewed-by: Yang Yingliang <yangyingliang@huawei.com>
Reviewed-by: Yao Hongbo <yaohongbo@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
arch/x86/kernel/apic/apic.c | 57 ++++++++++++++++++++-----------------
1 file changed, 31 insertions(+), 26 deletions(-)
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 84132eddb5a8..ae9a60fe7364 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -796,6 +796,24 @@ calibrate_by_pmtimer(long deltapm, long *delta, long *deltatsc)
return 0;
}
+static int __init lapic_init_clockevent(void)
+{
+ if (!lapic_timer_frequency)
+ return -1;
+
+ /* Calculate the scaled math multiplication factor */
+ lapic_clockevent.mult = div_sc(lapic_timer_frequency/APIC_DIVISOR,
+ TICK_NSEC, lapic_clockevent.shift);
+ lapic_clockevent.max_delta_ns =
+ clockevent_delta2ns(0x7FFFFFFF, &lapic_clockevent);
+ lapic_clockevent.max_delta_ticks = 0x7FFFFFFF;
+ lapic_clockevent.min_delta_ns =
+ clockevent_delta2ns(0xF, &lapic_clockevent);
+ lapic_clockevent.min_delta_ticks = 0xF;
+
+ return 0;
+}
+
static int __init calibrate_APIC_clock(void)
{
struct clock_event_device *levt = this_cpu_ptr(&lapic_events);
@@ -804,25 +822,21 @@ static int __init calibrate_APIC_clock(void)
long delta, deltatsc;
int pm_referenced = 0;
- /**
- * check if lapic timer has already been calibrated by platform
- * specific routine, such as tsc calibration code. if so, we just fill
+ if (boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER))
+ return 0;
+
+ /*
+ * Check if lapic timer has already been calibrated by platform
+ * specific routine, such as tsc calibration code. If so just fill
* in the clockevent structure and return.
*/
-
- if (boot_cpu_has(X86_FEATURE_TSC_DEADLINE_TIMER)) {
- return 0;
- } else if (lapic_timer_frequency) {
+ if (!lapic_init_clockevent()) {
apic_printk(APIC_VERBOSE, "lapic timer already calibrated %d\n",
- lapic_timer_frequency);
- lapic_clockevent.mult = div_sc(lapic_timer_frequency/APIC_DIVISOR,
- TICK_NSEC, lapic_clockevent.shift);
- lapic_clockevent.max_delta_ns =
- clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
- lapic_clockevent.max_delta_ticks = 0x7FFFFF;
- lapic_clockevent.min_delta_ns =
- clockevent_delta2ns(0xF, &lapic_clockevent);
- lapic_clockevent.min_delta_ticks = 0xF;
+ lapic_timer_frequency);
+ /*
+ * Direct calibration methods must have an always running
+ * local APIC timer, no need for broadcast timer.
+ */
lapic_clockevent.features &= ~CLOCK_EVT_FEAT_DUMMY;
return 0;
}
@@ -863,17 +877,8 @@ static int __init calibrate_APIC_clock(void)
pm_referenced = !calibrate_by_pmtimer(lapic_cal_pm2 - lapic_cal_pm1,
&delta, &deltatsc);
- /* Calculate the scaled math multiplication factor */
- lapic_clockevent.mult = div_sc(delta, TICK_NSEC * LAPIC_CAL_LOOPS,
- lapic_clockevent.shift);
- lapic_clockevent.max_delta_ns =
- clockevent_delta2ns(0x7FFFFFFF, &lapic_clockevent);
- lapic_clockevent.max_delta_ticks = 0x7FFFFFFF;
- lapic_clockevent.min_delta_ns =
- clockevent_delta2ns(0xF, &lapic_clockevent);
- lapic_clockevent.min_delta_ticks = 0xF;
-
lapic_timer_frequency = (delta * APIC_DIVISOR) / LAPIC_CAL_LOOPS;
+ lapic_init_clockevent();
apic_printk(APIC_VERBOSE, "..... delta %ld\n", delta);
apic_printk(APIC_VERBOSE, "..... mult: %u\n", lapic_clockevent.mult);
--
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