finished lab Backtrace

.vscode/settings.json

@@ -0,0 +1,5 @@
+{
+    "files.associations": {
+        "proc.h": "c"
+    }
+}

kernel/defs.h

@@ -80,6 +80,7 @@ int             pipewrite(struct pipe*, uint64, int);
 void            printf(char*, ...);
 void            panic(char*) __attribute__((noreturn));
 void            printfinit(void);
+void            backtrace(void);
 
 // proc.c
 int             cpuid(void);

kernel/printf.c

@@ -133,3 +133,16 @@ printfinit(void)
   initlock(&pr.lock, "pr");
   pr.locking = 1;
 }
+
+void
+backtrace(void) // For lab-4 Backtrace
+{
+  uint64 fp /* frame pointer */ = r_fp(),
+         ba /* base addr */ = PGROUNDUP(fp);
+
+  printf("backtrace:\n");
+  while (fp < ba) {
+    printf("%p\n", *(uint64*)(fp-8));
+    fp = *(uint64*)(fp-16);
+  }
+}

kernel/riscv.h

@@ -287,6 +287,14 @@ intr_get()
   return (x & SSTATUS_SIE) != 0;
 }
 
+static inline uint64
+r_fp()
+{
+  uint64 x;
+  asm volatile("mv %0, s0" : "=r" (x) );
+  return x;
+}
+
 static inline uint64
 r_sp()
 {

kernel/sysproc.c

@@ -53,7 +53,7 @@ sys_sleep(void)
 {
   int n;
   uint ticks0;
-
+  backtrace(); // For lab-4 Backtrace
   argint(0, &n);
   if(n < 0)
     n = 0;