diff options
| -rw-r--r-- | sys/x86/x86/local_apic.c | 60 |
1 files changed, 47 insertions, 13 deletions
diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c index b044fe9..a580f2a 100644 --- a/sys/x86/x86/local_apic.c +++ b/sys/x86/x86/local_apic.c @@ -56,6 +56,7 @@ __FBSDID("$FreeBSD$"); #include <vm/pmap.h> #include <x86/apicreg.h> +#include <machine/clock.h> #include <machine/cputypes.h> #include <machine/frame.h> #include <machine/intr_machdep.h> @@ -158,6 +159,9 @@ volatile lapic_t *lapic; vm_paddr_t lapic_paddr; static u_long lapic_timer_divisor; static struct eventtimer lapic_et; +#ifdef SMP +static uint64_t lapic_ipi_wait_mult; +#endif static void lapic_enable(void); static void lapic_resume(struct pic *pic, bool suspend_cancelled); @@ -221,6 +225,9 @@ lvt_mode(struct lapic *la, u_int pin, uint32_t value) void lapic_init(vm_paddr_t addr) { +#ifdef SMP + uint64_t r, r1, r2, rx; +#endif u_int regs[4]; int i, arat; @@ -275,6 +282,38 @@ lapic_init(vm_paddr_t addr) lapic_et.et_priv = NULL; et_register(&lapic_et); } + +#ifdef SMP +#define LOOPS 1000000 + /* + * Calibrate the busy loop waiting for IPI ack in xAPIC mode. + * lapic_ipi_wait_mult contains the number of iterations which + * approximately delay execution for 1 microsecond (the + * argument to native_lapic_ipi_wait() is in microseconds). + * + * We assume that TSC is present and already measured. + * Possible TSC frequency jumps are irrelevant to the + * calibration loop below, the CPU clock management code is + * not yet started, and we do not enter sleep states. + */ + KASSERT((cpu_feature & CPUID_TSC) != 0 && tsc_freq != 0, + ("TSC not initialized")); + r = rdtsc(); + for (rx = 0; rx < LOOPS; rx++) { + (void)lapic->icr_lo; + ia32_pause(); + } + r = rdtsc() - r; + r1 = tsc_freq * LOOPS; + r2 = r * 1000000; + lapic_ipi_wait_mult = r1 >= r2 ? r1 / r2 : 1; + if (bootverbose) { + printf("LAPIC: ipi_wait() us multiplier %ju (r %ju tsc %ju)\n", + (uintmax_t)lapic_ipi_wait_mult, (uintmax_t)r, + (uintmax_t)tsc_freq); + } +#undef LOOPS +#endif /* SMP */ } /* @@ -1381,25 +1420,20 @@ SYSINIT(apic_setup_io, SI_SUB_INTR, SI_ORDER_SECOND, apic_setup_io, NULL); * private to the MD code. The public interface for the rest of the * kernel is defined in mp_machdep.c. */ + +/* + * Wait delay microseconds for IPI to be sent. If delay is -1, we + * wait forever. + */ int lapic_ipi_wait(int delay) { - int x; - - /* - * Wait delay microseconds for IPI to be sent. If delay is - * -1, we wait forever. - */ - if (delay == -1) { - while ((lapic->icr_lo & APIC_DELSTAT_MASK) != APIC_DELSTAT_IDLE) - ia32_pause(); - return (1); - } + uint64_t rx; - for (x = 0; x < delay; x += 5) { + for (rx = 0; delay == -1 || rx < lapic_ipi_wait_mult * delay; rx++) { if ((lapic->icr_lo & APIC_DELSTAT_MASK) == APIC_DELSTAT_IDLE) return (1); - DELAY(5); + ia32_pause(); } return (0); } |
