schedrelease() syscall for more efficient spinning

kernel/hal/x86_64/intr.c

@@ -17,6 +17,8 @@
 #include "proc/ps2kbproc/ps2kbproc.h"
 #include "rbuf/rbuf.h"
 
+IntrStackFrame *INTR_CURRENT_FRAME;
+
 typedef struct BackTraceFrame {
   struct BackTraceFrame *rbp;
   uint64_t rip;
@@ -196,6 +198,8 @@ void intr_eoi(uint8_t irq) {
 }
 
 void intr_handleintr(IntrStackFrame *frame) {
+  INTR_CURRENT_FRAME = frame;
+
   if (frame->trapnum <= 31) {
     kprintf("ERROR %s, 0x%lX\n", exceptions[frame->trapnum], frame->errnum);
     intr_dumpframe(frame);

kernel/hal/x86_64/intr.h

@@ -35,4 +35,6 @@ typedef struct {
 
 void intr_init(void);
 
+IntrStackFrame *INTR_CURRENT_FRAME;
+
 #endif // HAL_INTR_H_

kernel/syscall/sched.c

@@ -0,0 +1,17 @@
+#include <stdint.h>
+#include "syscall.h"
+#include "sched.h"
+#include "proc/proc.h"
+#include "spinlock/spinlock.h"
+#include "errors.h"
+#include "hal/hal.h"
+
+int32_t SYSCALL0(sys_schedrelease) {
+  spinlock_acquire(&PROCS.spinlock);
+  Proc *proc = PROCS.current;
+  spinlock_release(&PROCS.spinlock);
+
+  proc_sched((void *)INTR_CURRENT_FRAME);
+
+  return E_OK;
+}

kernel/syscall/sched.h

@@ -0,0 +1,9 @@
+#ifndef SYSCALL_SCHED_H_
+#define SYSCALL_SCHED_H_
+
+#include <stdint.h>
+#include "syscall.h"
+
+int32_t SYSCALL0(sys_schedrelease);
+
+#endif // SYSCALL_SCHED_H_

kernel/syscall/syscall.c

@@ -7,6 +7,7 @@
 #include "ioctl.h"
 #include "ipcpipe.h"
 #include "mman.h"
+#include "sched.h"
 
 int32_t SYSCALL1(sys_debugprint, string) {
   char *p = (char *)string;
@@ -21,4 +22,5 @@ SyscallFn SYSCALL_TABLE[SYSCALLS_MAX] = {
   [SYS_IPCPIPE]    = &sys_ipcpipe,
   [SYS_MMAN_MAP]   = &sys_mman_map,
   [SYS_MMAN_UNMAP] = &sys_mman_unmap,
+  [SYS_SCHEDRELEASE] = &sys_schedrelease,
 };