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x86: Defer LAPIC calibration until after timecounters are available

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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
This commit is contained in:
Mark Johnston 2021-12-06 10:42:10 -05:00
parent f06f1d1fdb
commit 62d09b46ad
5 changed files with 51 additions and 28 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
sys/x86/include/apicvar.h
View File

@ -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)
{

1
sys/x86/include/clock.h
View File

@ -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.

4
sys/x86/isa/clock.c
View File

@ -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
}

57
sys/x86/x86/local_apic.c
View File

@ -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:

7
sys/x86/xen/xen_apic.c
View File

@ -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,