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_