Applied, thanks!
Damien Zammit, le lun. 06 mars 2023 07:05:03 +0000, a ecrit:
> Previously the lapic timer was calibrated by one-shot PIT timer2.
> This method can be buggy and generally unused in emulation environments.
> This patch reworks the timer calibration to use a mach timer based
> on regular PIT interrupts to remapped IOAPIC pin.
> This also changes the primary clock source to use PIT timer0 remapped
> to an IOAPIC pin when APIC mode is enabled, instead of a periodic lapic
> timer.
> ---
> i386/i386/apic.h | 3 +-
> i386/i386at/ioapic.c | 81 +++++++++++++++++++++++------------------
> i386/i386at/model_dep.c | 8 +++-
> 3 files changed, 54 insertions(+), 38 deletions(-)
>
> diff --git a/i386/i386/apic.h b/i386/i386/apic.h
> index ac083d26..a79f0ea8 100644
> --- a/i386/i386/apic.h
> +++ b/i386/i386/apic.h
> @@ -243,11 +243,12 @@ void lapic_eoi(void);
> void ioapic_irq_eoi(int pin);
> void lapic_enable(void);
> void lapic_enable_timer(void);
> +void calibrate_lapic_timer(void);
> void ioapic_mask_irqs(void);
> void ioapic_toggle(int pin, int mask);
> void ioapic_configure(void);
>
> -extern int duplicate_pin;
> +extern int timer_pin;
> extern void intnull(int unit);
> extern volatile ApicLocalUnit* lapic;
>
> diff --git a/i386/i386at/ioapic.c b/i386/i386at/ioapic.c
> index d2ea84ad..c6da35e1 100644
> --- a/i386/i386at/ioapic.c
> +++ b/i386/i386at/ioapic.c
> @@ -28,11 +28,13 @@
> #include <i386/pio.h>
> #include <i386/pit.h>
> #include <i386/pic.h> /* only for macros */
> +#include <i386/smp.h>
> #include <mach/machine.h>
> #include <kern/printf.h>
> +#include <kern/timer.h>
>
> static int has_irq_specific_eoi = 1; /* FIXME: Assume all machines have this
> */
> -int duplicate_pin;
> +int timer_pin;
>
> uint32_t lapic_timer_val = 0;
> uint32_t calibrated_ticks = 0;
> @@ -43,7 +45,7 @@ int iunit[NINTR] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
> 12, 13, 14, 15,
> 16, 17, 18, 19, 20, 21, 22, 23};
>
> interrupt_handler_fn ivect[NINTR] = {
> - /* 00 */ intnull, /* install timer later */
> + /* 00 */ (interrupt_handler_fn)hardclock,
> /* 01 */ kdintr, /* kdintr, ... */
> /* 02 */ intnull,
> /* 03 */ intnull, /* lnpoll, comintr, ... */
> @@ -150,32 +152,58 @@ ioapic_toggle_entry(int apic, int pin, int mask)
> ioapic_write(apic, APIC_IO_REDIR_LOW(pin), entry.lo);
> }
>
> +static void timer_expiry_callback(void *arg)
> +{
> + volatile int *done = arg;
> + *done = 1;
> +}
> +
> static uint32_t
> -pit_measure_10x_apic_hz(void)
> +timer_measure_10x_apic_hz(void)
> {
> - volatile int i;
> + volatile int done = 0;
> uint32_t start = 0xffffffff;
> + timer_elt_data_t tmp_timer;
> + tmp_timer.fcn = timer_expiry_callback;
> + tmp_timer.param = (void *)&done;
>
> - /* Prepare accurate delay for 1/hz seconds */
> - pit_prepare_sleep(hz);
> + printf("timer calibration...");
>
> /* Set APIC timer */
> lapic->init_count.r = start;
>
> - /* zZz */
> - for (i = 0; i < 10; i++)
> - pit_sleep();
> + /* Delay for 10 * 1/hz seconds */
> + set_timeout(&tmp_timer, hz / 10);
> + do {
> + cpu_pause();
> + } while (!done);
>
> /* Stop APIC timer */
> lapic->lvt_timer.r |= LAPIC_DISABLE;
>
> + printf(" done\n");
> +
> return start - lapic->cur_count.r;
> }
>
> -void lapic_update_timer(void)
> +void
> +calibrate_lapic_timer(void)
> {
> - /* Timer decrements until zero and then calls this on every interrupt */
> - lapic_timer_val += calibrated_ticks;
> + spl_t s;
> +
> + /* Set one-shot timer */
> + lapic->divider_config.r = LAPIC_TIMER_DIVIDE_2;
> + lapic->lvt_timer.r = IOAPIC_INT_BASE;
> +
> + /* Measure number of APIC timer ticks in 10x 1/hz seconds
> + * but calibrate the timer to expire at rate of hz
> + * divide by 10 because we waited 10 times longer than we needed. */
> + if (!calibrated_ticks) {
> + s = splhigh();
> + spl0();
> + calibrated_ticks = timer_measure_10x_apic_hz() / 10;
> + splx(s);
> + }
> }
>
> void
> @@ -306,16 +334,14 @@ ioapic_configure(void)
> /* Save timer info */
> timer_gsi = gsi;
> } else {
> - /* Disable duplicated timer gsi */
> + /* Remap timer irq */
> if (gsi == timer_gsi) {
> - duplicate_pin = pin;
> - /* Remap this interrupt pin to GSI base
> - * so we don't duplicate vectors */
> + timer_pin = pin;
> + /* Remap GSI base to timer pin so ivect[0] is the timer */
> entry.both.vector = IOAPIC_INT_BASE;
> - ioapic_write_entry(apic, duplicate_pin, entry.both);
> - /* Mask the ioapic pin with deduplicated vector as
> - * we will never use it, since timer is on another gsi */
> - mask_irq(duplicate_pin);
> + ioapic_write_entry(apic, timer_pin, entry.both);
> + /* Mask the duplicate pin 0 as we will be using timer_pin */
> + mask_irq(0);
> }
> }
> }
> @@ -337,20 +363,5 @@ ioapic_configure(void)
> /* Start the IO APIC receiving interrupts */
> lapic_enable();
>
> - /* Set one-shot timer */
> - lapic->divider_config.r = LAPIC_TIMER_DIVIDE_2;
> - lapic->lvt_timer.r = IOAPIC_INT_BASE;
> -
> - /* Measure number of APIC timer ticks in 10x 1/hz seconds
> - * but calibrate the timer to expire at rate of hz
> - * divide by 10 because we waited 10 times longer than we needed */
> - calibrated_ticks = pit_measure_10x_apic_hz() / 10;
> -
> - /* Set up counter later */
> - lapic->lvt_timer.r = LAPIC_DISABLE;
> -
> - /* Install clock interrupt handler on pin 0 */
> - ivect[0] = (interrupt_handler_fn)hardclock;
> -
> printf("IOAPIC 0 configured\n");
> }
> diff --git a/i386/i386at/model_dep.c b/i386/i386at/model_dep.c
> index baff8da1..e8462ba3 100644
> --- a/i386/i386at/model_dep.c
> +++ b/i386/i386at/model_dep.c
> @@ -171,7 +171,7 @@ void machine_init(void)
> #if defined(APIC)
> ioapic_configure();
> #endif
> - startrtclock();
> + clkstart();
>
> #if defined(APIC)
> #warning FIXME: Rather unmask them from their respective drivers
> @@ -593,7 +593,11 @@ void
> startrtclock(void)
> {
> #ifdef APIC
> - lapic_enable_timer();
> + unmask_irq(timer_pin);
> + calibrate_lapic_timer();
> + if (cpu_number() != 0) {
> + lapic_enable_timer();
> + }
> #else
> clkstart();
> unmask_irq(0);
> --
> 2.39.0
>
>
>
--
Samuel
---
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Je soutiens la Commission d'Évaluation de l'Inria.
