use bootstrap processor as specified by MP table. typically 0, but not

guaranteed.

use bootstrap processor as specified by MP table. typically 0, but not
5cb7877e · kaashoek · f80873e6 · 5cb7877e · 5cb7877e
--- a/main.c
+++ b/main.c
@@ -23,22 +23,24 @@ void
 main0(void)
 {
  int i;
+  int bcpu;
  struct proc *p;
  // clear BSS
  memset(edata, 0, end - edata);
-  // switch to bootstrap processor's stack
-  asm volatile("movl %0, %%esp" : : "r" (cpus[0].mpstack + MPSTACK - 32));
-  asm volatile("movl %0, %%ebp" : : "r" (cpus[0].mpstack + MPSTACK));
  // Prevent release() from enabling interrupts.
  for(i=0; i<NCPU; i++)
    cpus[i].nlock = 1;
  mp_init(); // collect info about this machine
+  bcpu = mp_bcpu();
+  // switch to bootstrap processor's stack
+  asm volatile("movl %0, %%esp" : : "r" (cpus[0].mpstack + MPSTACK - 32));
+  asm volatile("movl %0, %%ebp" : : "r" (cpus[0].mpstack + MPSTACK));
-  lapic_init(mp_bcpu());
+  lapic_init(bcpu);
  cprintf("\ncpu%d: starting xv6\n\n", cpu());

--- a/mp.c
+++ b/mp.c
@@ -191,7 +191,8 @@ mp_init(void)
 int
 mp_bcpu(void)
 {
-  return bcpu-cpus;
+  if (ismp) return bcpu-cpus;
+  else return 0;
 }
 extern void mpmain(void);