Major restructure

kern/proc.h

@@ -1,3 +1,6 @@
+#include <config.h>
+#include <spinlock.h>
+#include <riscv.h>
 #include <stdint.h>
 
 typedef enum {
@@ -37,6 +40,7 @@ struct Cpu {
     int             intena;  // Were interrupts enabled before push_off()?
 };
 
+/** Saved registers for kernel context switches. */
 typedef struct {
     /*   0 */ uint64_t kernel_satp;   // kernel page table
     /*   8 */ uint64_t kernel_sp;     // top of process's kernel stack
@@ -75,3 +79,10 @@ typedef struct {
     /* 272 */ uint64_t t5;
     /* 280 */ uint64_t t6;
 } TrapFrame_t;
+
+struct Cpu *mycpu(void);
+
+extern struct Cpu cpus[NCPU];
+
+/** Per-process state */
+struct Proc {};