git: 62d09b46ad75 - main - x86: Defer LAPIC calibration until after timecounters are available
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Date: Mon, 06 Dec 2021 16:21:49 UTC
The branch main has been updated by markj:
URL: https://cgit.FreeBSD.org/src/commit/?id=62d09b46ad7508ae74d462e49234f0a80f91ff69
commit 62d09b46ad7508ae74d462e49234f0a80f91ff69
Author: Mark Johnston <markj@FreeBSD.org>
AuthorDate: 2021-12-06 15:42:10 +0000
Commit: Mark Johnston <markj@FreeBSD.org>
CommitDate: 2021-12-06 15:42:10 +0000
x86: Defer LAPIC calibration until after timecounters are available
This ensures that we have a good reference timecounter for performing
calibration.
Change lapic_setup to avoid configuring the timer when booting, and move
calibration and initial configuration to a new lapic routine,
lapic_calibrate_timer. This calibration will be initiated from
cpu_initclocks(), before an eventtimer is selected.
Reviewed by: kib, jhb
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D33206
---
sys/x86/include/apicvar.h | 10 +++++++++
sys/x86/include/clock.h | 1 +
sys/x86/isa/clock.c | 4 ++++
sys/x86/x86/local_apic.c | 57 ++++++++++++++++++++++++-----------------------
sys/x86/xen/xen_apic.c | 7 ++++++
5 files changed, 51 insertions(+), 28 deletions(-)
diff --git a/sys/x86/include/apicvar.h b/sys/x86/include/apicvar.h
index f1794afa0bbd..373e7d576426 100644
--- a/sys/x86/include/apicvar.h
+++ b/sys/x86/include/apicvar.h
@@ -229,6 +229,9 @@ struct apic_ops {
void (*disable_vector)(u_int, u_int);
void (*free_vector)(u_int, u_int, u_int);
+ /* Timer */
+ void (*calibrate_timer)(void);
+
/* PMC */
int (*enable_pmc)(void);
void (*disable_pmc)(void);
@@ -376,6 +379,13 @@ apic_free_vector(u_int apic_id, u_int vector, u_int irq)
apic_ops.free_vector(apic_id, vector, irq);
}
+static inline void
+lapic_calibrate_timer(void)
+{
+
+ apic_ops.calibrate_timer();
+}
+
static inline int
lapic_enable_pmc(void)
{
diff --git a/sys/x86/include/clock.h b/sys/x86/include/clock.h
index 86a4541568ed..d492196bac85 100644
--- a/sys/x86/include/clock.h
+++ b/sys/x86/include/clock.h
@@ -27,6 +27,7 @@ extern int smp_tsc;
void i8254_init(void);
void i8254_delay(int);
void clock_init(void);
+void lapic_calibrate(void);
/*
* Driver to clock driver interface.
diff --git a/sys/x86/isa/clock.c b/sys/x86/isa/clock.c
index 568097d18fdf..2eb1c343f4db 100644
--- a/sys/x86/isa/clock.c
+++ b/sys/x86/isa/clock.c
@@ -66,6 +66,7 @@ __FBSDID("$FreeBSD$");
#include <machine/intr_machdep.h>
#include <machine/ppireg.h>
#include <machine/timerreg.h>
+#include <x86/apicvar.h>
#include <x86/init.h>
#include <isa/rtc.h>
@@ -411,6 +412,8 @@ cpu_initclocks(void)
int i;
td = curthread;
+
+ lapic_calibrate_timer();
cpu_initclocks_bsp();
CPU_FOREACH(i) {
if (i == 0)
@@ -425,6 +428,7 @@ cpu_initclocks(void)
sched_unbind(td);
thread_unlock(td);
#else
+ lapic_calibrate_timer();
cpu_initclocks_bsp();
#endif
}
diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c
index 778760be1921..7e8db869a884 100644
--- a/sys/x86/x86/local_apic.c
+++ b/sys/x86/x86/local_apic.c
@@ -221,7 +221,6 @@ SYSCTL_INT(_hw_apic, OID_AUTO, ds_idle_timeout, CTLFLAG_RWTUN,
#endif
static void lapic_calibrate_initcount(struct lapic *la);
-static void lapic_calibrate_deadline(struct lapic *la);
/*
* Use __nosanitizethread to exempt the LAPIC I/O accessors from KCSan
@@ -373,6 +372,7 @@ static void native_apic_enable_vector(u_int apic_id, u_int vector);
static void native_apic_free_vector(u_int apic_id, u_int vector, u_int irq);
static void native_lapic_set_logical_id(u_int apic_id, u_int cluster,
u_int cluster_id);
+static void native_lapic_calibrate_timer(void);
static int native_lapic_enable_pmc(void);
static void native_lapic_disable_pmc(void);
static void native_lapic_reenable_pmc(void);
@@ -412,6 +412,7 @@ struct apic_ops apic_ops = {
.enable_vector = native_apic_enable_vector,
.disable_vector = native_apic_disable_vector,
.free_vector = native_apic_free_vector,
+ .calibrate_timer = native_lapic_calibrate_timer,
.enable_pmc = native_lapic_enable_pmc,
.disable_pmc = native_lapic_disable_pmc,
.reenable_pmc = native_lapic_reenable_pmc,
@@ -804,21 +805,18 @@ native_lapic_setup(int boot)
LAPIC_LVT_PCINT));
}
- /* Program timer LVT. */
+ /*
+ * Program the timer LVT. Calibration is deferred until it is certain
+ * that we have a reliable timecounter.
+ */
la->lvt_timer_base = lvt_mode(la, APIC_LVT_TIMER,
lapic_read32(LAPIC_LVT_TIMER));
la->lvt_timer_last = la->lvt_timer_base;
lapic_write32(LAPIC_LVT_TIMER, la->lvt_timer_base);
- /* Calibrate the timer parameters using BSP. */
- if (boot && IS_BSP()) {
- lapic_calibrate_initcount(la);
- if (lapic_timer_tsc_deadline)
- lapic_calibrate_deadline(la);
- }
-
- /* Setup the timer if configured. */
- if (la->la_timer_mode != LAT_MODE_UNDEF) {
+ if (boot)
+ la->la_timer_mode = LAT_MODE_UNDEF;
+ else if (la->la_timer_mode != LAT_MODE_UNDEF) {
KASSERT(la->la_timer_period != 0, ("lapic%u: zero divisor",
lapic_id()));
switch (la->la_timer_mode) {
@@ -909,6 +907,25 @@ lapic_update_pmc(void *dummy)
}
#endif
+static void
+native_lapic_calibrate_timer(void)
+{
+ struct lapic *la;
+ register_t intr;
+
+ intr = intr_disable();
+ la = &lapics[lapic_id()];
+
+ lapic_calibrate_initcount(la);
+
+ intr_restore(intr);
+
+ if (lapic_timer_tsc_deadline && bootverbose) {
+ printf("lapic: deadline tsc mode, Frequency %ju Hz\n",
+ (uintmax_t)tsc_freq);
+ }
+}
+
static int
native_lapic_enable_pmc(void)
{
@@ -999,27 +1016,11 @@ lapic_calibrate_initcount(struct lapic *la)
count_freq = value;
}
-static void
-lapic_calibrate_deadline(struct lapic *la __unused)
-{
-
- if (bootverbose) {
- printf("lapic: deadline tsc mode, Frequency %ju Hz\n",
- (uintmax_t)tsc_freq);
- }
-}
-
static void
lapic_change_mode(struct eventtimer *et, struct lapic *la,
enum lat_timer_mode newmode)
{
-
- /*
- * The TSC frequency may change during late calibration against other
- * timecounters (HPET or ACPI PMTimer).
- */
- if (la->la_timer_mode == newmode &&
- (newmode != LAT_MODE_DEADLINE || et->et_frequency == tsc_freq))
+ if (la->la_timer_mode == newmode)
return;
switch (newmode) {
case LAT_MODE_PERIODIC:
diff --git a/sys/x86/xen/xen_apic.c b/sys/x86/xen/xen_apic.c
index 01dae36de2e8..b553e5248716 100644
--- a/sys/x86/xen/xen_apic.c
+++ b/sys/x86/xen/xen_apic.c
@@ -223,6 +223,12 @@ xen_pv_apic_free_vector(u_int apic_id, u_int vector, u_int irq)
XEN_APIC_UNSUPPORTED;
}
+static void
+xen_pv_lapic_calibrate_timer(void)
+{
+
+}
+
static void
xen_pv_lapic_set_logical_id(u_int apic_id, u_int cluster, u_int cluster_id)
{
@@ -420,6 +426,7 @@ struct apic_ops xen_apic_ops = {
.enable_vector = xen_pv_apic_enable_vector,
.disable_vector = xen_pv_apic_disable_vector,
.free_vector = xen_pv_apic_free_vector,
+ .calibrate_timer = xen_pv_lapic_calibrate_timer,
.enable_pmc = xen_pv_lapic_enable_pmc,
.disable_pmc = xen_pv_lapic_disable_pmc,
.reenable_pmc = xen_pv_lapic_reenable_pmc,