Schedule inside of systick_irq

kernel/amd64/apic.c

@@ -239,12 +239,12 @@ static uint32_t lapic_calibrate (uint32_t us) {
 
   lapic_write (LAPIC_DCR, DIVIDER_VALUE);
 
-  lapic_write (LAPIC_LVTTR, INTR_SCHED_PREEMPT_TIMER | (1 << 16));
+  lapic_write (LAPIC_LVTTR, INTR_SYSTICK | (1 << 16));
   lapic_write (LAPIC_TIMICT, 0xFFFFFFFF);
 
   sleep_micro (us);
 
-  lapic_write (LAPIC_LVTTR, INTR_SCHED_PREEMPT_TIMER | (0 << 16));
+  lapic_write (LAPIC_LVTTR, INTR_SYSTICK | (0 << 16));
   uint32_t ticks = 0xFFFFFFFF - lapic_read (LAPIC_TIMCCT);
   DEBUG ("timer ticks = %u\n", ticks);
 
@@ -254,14 +254,14 @@ static uint32_t lapic_calibrate (uint32_t us) {
 }
 
 /*
- * Starts a Local APIC, configures LVT timer to send interrupts at SCHED_PREEMPT_TIMER.
+ * Starts a Local APIC, configures LVT timer to send interrupts at SYSTICK.
  *
  * ticks - Initial tick count
  */
 static void lapic_start (uint32_t ticks) {
   lapic_write (LAPIC_DCR, DIVIDER_VALUE);
   lapic_write (LAPIC_TIMICT, ticks);
-  lapic_write (LAPIC_LVTTR, INTR_SCHED_PREEMPT_TIMER | (1 << 17));
+  lapic_write (LAPIC_LVTTR, INTR_SYSTICK | (1 << 17));
 }
 
 /*

kernel/amd64/bootmain.c

@@ -7,6 +7,7 @@
 #include <amd64/msr-index.h>
 #include <amd64/msr.h>
 #include <amd64/sse.h>
+#include <amd64/systick.h>
 #include <aux/compiler.h>
 #include <device/device.h>
 #include <device/storage/partitions.h>
@@ -62,7 +63,7 @@ void bootmain (void) {
 
   bsp_cpu->kproc = kproc_create ();
 
-  lapic_init (5000);
+  lapic_init (1000);
 
   __asm__ volatile ("sti");
 
@@ -78,7 +79,7 @@ void bootmain (void) {
   struct device* temp0 = device_find ("temp0");
   vfs_create_volume (thiscpu->kproc, &rctx, "temp", FS_FAT16, temp0, true);
 
-  irq_attach (&proc_irq_sched, NULL, INTR_SCHED_PREEMPT_TIMER);
+  irq_attach (&systick_irq, NULL, INTR_SYSTICK);
   irq_attach (&proc_irq_sched, NULL, INTR_CPU_REQUEST_SCHED);
 
   smp_init ();

kernel/amd64/intr.c

@@ -126,7 +126,7 @@ static void idt_init (void) {
   IDT_ENTRY (40, 2); IDT_ENTRY (41, 2); IDT_ENTRY (42, 2); IDT_ENTRY (43, 2);
   IDT_ENTRY (44, 2); IDT_ENTRY (45, 2); IDT_ENTRY (46, 2); IDT_ENTRY (47, 2);
 
-  IDT_ENTRY (INTR_SCHED_PREEMPT_TIMER, 2);
+  IDT_ENTRY (INTR_SYSTICK, 2);
   IDT_ENTRY (INTR_CPU_REQUEST_SCHED, 2);
   IDT_ENTRY (INTR_CPU_SPURIOUS, 2);
   /* clang-format on */

kernel/amd64/intr_defs.h

@@ -6,8 +6,8 @@
 #define INTR_IDE_DRIVE_SCND 34
 #define INTR_XHCI           35
 
-#define INTR_SCHED_PREEMPT_TIMER 80
-#define INTR_CPU_REQUEST_SCHED   82
-#define INTR_CPU_SPURIOUS        255
+#define INTR_SYSTICK           80
+#define INTR_CPU_REQUEST_SCHED 82
+#define INTR_CPU_SPURIOUS      255
 
 #endif // _KERNEL_AMD64_INTR_DEFS_H

kernel/amd64/intr_stub.S

@@ -91,6 +91,6 @@ make_intr_stub(no_err, 45)
 make_intr_stub(no_err, 46)
 make_intr_stub(no_err, 47)
 
-make_intr_stub(no_err, INTR_SCHED_PREEMPT_TIMER)
+make_intr_stub(no_err, INTR_SYSTICK)
 make_intr_stub(no_err, INTR_CPU_REQUEST_SCHED)
 make_intr_stub(no_err, INTR_CPU_SPURIOUS)

kernel/amd64/smp.c

@@ -100,7 +100,7 @@ static void smp_bootstrap (struct limine_mp_info* mp_info) {
   syscall_init ();
   sse_enable ();
 
-  lapic_init (5000);
+  lapic_init (1000);
 
   DEBUG ("CPU %u is online!\n", thiscpu->id);
 

kernel/amd64/src.mk

@@ -13,7 +13,8 @@ c += amd64/bootmain.c \
 		 amd64/proc.c \
 		 amd64/syscall.c \
 		 amd64/gdt.c \
-		 amd64/stall.c
+		 amd64/stall.c \
+		 amd64/systick.c
 
 S += amd64/intr_stub.S \
 		 amd64/spin.S \
@@ -41,4 +42,5 @@ o += amd64/bootmain.o \
 		 amd64/syscallentry.o \
 		 amd64/gdt.o \
 		 amd64/sse.o \
-		 amd64/stall.o
+		 amd64/stall.o \
+		 amd64/systick.o

kernel/amd64/systick.c

@@ -0,0 +1,12 @@
+#include <libk/std.h>
+#include <proc/reschedule.h>
+#include <sys/smp.h>
+
+static uint32_t systicks = 0;
+
+void systick_irq (void* arg, void* regs, bool user, struct reschedule_ctx* rctx) {
+  systicks++;
+
+  if (systicks % 5 == 0)
+    rctx_insert_cpu (rctx, thiscpu);
+}

kernel/amd64/systick.h

@@ -0,0 +1,9 @@
+#ifndef _KERNEL_AMD64_SYSTICK_H
+#define _KERNEL_AMD64_SYSTICK_H
+
+#include <libk/std.h>
+#include <proc/reschedule.h>
+
+void systick_irq (void* arg, void* regs, bool user, struct reschedule_ctx* rctx);
+
+#endif // // _KERNEL_AMD64_SYSTICK_H