Revert "print kernel stacktrace for exceptions in kernel"

This reverts commit eff1369cab.

This was in a working branch and I only intended to commit
exception.c. But I committed the exact inverse. Sorry.

kernel/system/do_fork.c

@@ -65,13 +65,10 @@ PUBLIC int do_fork(struct proc * caller, message * m_ptr)
 #if (_MINIX_CHIP == _CHIP_INTEL)
   rpc->p_seg.p_ldt_sel = old_ldt_sel;	/* restore descriptors */
   rpc->p_fpu_state.fpu_save_area_p = old_fpu_save_area_p;
-  if(proc_used_fpu(rpp)) {
-  	fpu_verifychecksum(rpp);
+  if(proc_used_fpu(rpp))
 	memcpy(rpc->p_fpu_state.fpu_save_area_p,
 	       rpp->p_fpu_state.fpu_save_area_p,
 	       FPU_XFP_SIZE);
-  	fpu_verifychecksum(rpc);
-  }
 #endif
   if(++gen >= _ENDPOINT_MAX_GENERATION)	/* increase generation */
 	gen = 1;			/* generation number wraparound */

kernel/system/do_mcontext.c

@@ -86,7 +86,6 @@ PUBLIC int do_setmcontext(struct proc * caller, message * m_ptr)
 	rp->p_misc_flags |= MF_FPU_INITIALIZED;
 	memcpy(rp->p_fpu_state.fpu_save_area_p, &(mc.mc_fpu_state),
 								FPU_XFP_SIZE);
-	fpu_makechecksum(rp);
   } else
 	rp->p_misc_flags &= ~MF_FPU_INITIALIZED;
   /* force reloading FPU in either case */

kernel/system/do_sigreturn.c

@@ -56,10 +56,8 @@ PUBLIC int do_sigreturn(struct proc * caller, message * m_ptr)
 #if (_MINIX_CHIP == _CHIP_INTEL)
   if(sc.sc_flags & MF_FPU_INITIALIZED)
   {
-	fpu_verifychecksum(rp);
 	memcpy(rp->p_fpu_state.fpu_save_area_p, &sc.sc_fpu_state,
 		FPU_XFP_SIZE);
-	fpu_makechecksum(rp);
 	rp->p_misc_flags |=  MF_FPU_INITIALIZED; /* Restore math usage flag. */
 	/* force reloading FPU */
 	release_fpu(rp);