Program LAPIC deadline

arch/x86_64/apic.c

@@ -7,6 +7,7 @@
 #include <zinnia/utils.h>
 #include <zinnia/vma.h>
 #include <arch/cpu.h>
+#include <arch/timer.h>
 #include <stdint.h>
 #include <x86_64/apic.h>
 #include <x86_64/asm.h>
@@ -95,17 +96,22 @@ void lapic_init(struct local_apic* lapic) {
     clock_spin_ns(10'000'000);
 
     lapic->ticks_per_10ms = 0xFFFF'FFFF - lapic_read_reg(lapic, APIC_REG_CCR);
-    lapic_write_reg(lapic, APIC_REG_LVT_TR, IDT_IPI_RESCHED | 0x20000);
-    lapic_write_reg(lapic, APIC_REG_ICR_TIMER, lapic->ticks_per_10ms);
+    lapic_write_reg(lapic, APIC_REG_LVT_TR, mmio_field(APIC_LVT_TR_VECTOR, IDT_TIMER));
+    lapic_write_reg(lapic, APIC_REG_ICR_TIMER, 0);
+}
+
+void arch_timer_program(uint64_t deadline_ns) {
+    struct local_apic* lapic = &percpu_ref(arch_data)->lapic;
+    const uint64_t now = clock_get_elapsed_ns();
+    const uint64_t delta = MIN(deadline_ns > now ? deadline_ns - now : 0, 1'000'000'000);
+    const uint64_t ticks = delta * lapic->ticks_per_10ms / 10'000'000;
+    lapic_write_reg(lapic, APIC_REG_ICR_TIMER, MIN(MAX(ticks, 1), 0xFFFF'FFFF));
 }
 
 void lapic_eoi(struct local_apic* lapic) {
     lapic_write_reg(lapic, APIC_REG_EOI, 0);
 }
 
-constexpr uint64_t the_icr =
-    mmio_field(APIC_ICR_VECTOR, 128) | mmio_field(APIC_ICR_DELIVERY_MODE, APIC_DELIVERY_STARTUP);
-
 void lapic_send_ipi(
     struct local_apic* lapic,
     uint32_t target,

include/arch/timer.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#include <stdint.h>
+
+void arch_timer_program(uint64_t deadline_ns);